ML061780088

Comment (1) of Matthew Brock on Behalf of Massachusetts Attorney General Thomas F. Reilly, on the Proposed Scope of the Supplemental Generic Environmental Impact Statement (Supplemental GEIS) for the Renewal of the Vermont Yankee Nuclear Pl

ML061780088
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/15/2006
From:	Brock M Harmon, Curran, Harmon, Curran, Spielberg & Eisenberg, LLP
To:	NRC/ADM/DAS/RDB
References
71FR20733 00001
Download: ML061780088 (357)

Text

HARMON, CURRAN, SPIELBERG EISENBERG, LLP 1726 M Street, NW, Suite 600 Washington, DC 20036 202) 328-3500 (202) 328-6918 fax

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0 rri June 15, 2006 C, 7) j.-i-.I BY FEDERAL EXPRESS Chief, Rules and Directives Branch ~T1 4=

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Division of Administrative Services rri Cr)

Office of Administration Room T-6D59 Two White Flint North 11545 Rockville Pike Rockville, MD 20952 301-415-1590

SUBJECT:

EIS Scoping Processfor Vermont Yankee NuclearPlantLicense Renewal, 71 Fed.Reg. 20,733 (April 21, 2006)

Dear Madam/Sir:

On behalf of Massachusetts Attorney General Thomas F. Reilly, we are writing to submit comments on the proposed scope of the supplemental Generic Environmental Impact Statement ("Supplemental GEIS") for the renewal of the Vermont Yankee nuclear power plant operating license. The Attorney General seeks consideration in the Supplemental GEIS of the environmental impacts of a severe accident in the Vermont Yankee fuel pool, including accidents caused by equipment failures, natural disasters, and intentional malicious acts. The Attorney General also seeks consideration of a reasonable array of alternatives for avoiding or mitigating the impacts of a severe pool fire, including combined low-density pool storage and dry storage of spent fuel.

The technical grounds for the Attorney General's request are discussed in detail in the enclosed Hearing Request, submitted to the Commission on May 26, 2006.1 The Hearing Request also discusses the basis for the Attorney General's position that the analysis he seeks is required by U.S. Nuclear Regulatory Commission ("NRC") regulations and the National Environmental Policy Act ("NEPA").

In addition, we wish to draw your attention to a recent decision by the U.S. Court of Appeals for the Ninth Circuit, in which the Court ruled that the Commission's rationale i Massachusetts Attorney General's Request for a Hearing and Petition to Intervene With Respect to Entergy Nuclear Operations Inc.'s Application for Renewal of the Vermont Yankee Nuclear Plant Operating License, etc. (May 26, 2006) ("Hearing Request"). The Hearing Request is now pending before the Atomic Safety and Licensing Board. - . 7. , ,

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HARMON, CURRAN, SPIELBERG ,EISENBERG, LLP Chief, Rules and Directives Branch June 15, 2006 Page 2 for refusing to consider the environmental impacts of intentional malicious attacks against nuclear facilities, as set forth in PrivateFuel Storage (Independent Spent Fuel Storage Installation), CLI-02-25, 56 NRC 340 (2002) ("PFS"), fails to meet NEPA's reasonableness standard. San Luis ObispoMothersfor Peace v. NuclearRegulatory Commission, No. 03-74628 (June 2, 2006) ("Mothersfor Peace"). A copy of the decision is enclosed. The Mothersfor Peace decision constitutes a significant precedent that supports including the environmental impacts of intentional malicious attacks on the Vermont Yankee pool within the scope of the Supplemental EIS.

Sincerely, ine Curran Matthew Brock, Assistant Attorney General Environmental Protection Division Office of the Attorney General One Ashburton Place Boston, MA 02108

Enclosure:

As stated

FOR PUBLICATION UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT SAN Luis OBISPO MOTHERS FOR PEACE; SANTA LUCIA CHAPTER OF THE SIERRA CLUB; PEG PINARD, Petitioners, No. 03-74628 PACIFIC GAS AND ELECTRIC NRC No.

COMPANY, CLI-03-01; Intervenor, CLI-02-23 V. OPINION NUCLEAR REGULATORY COMMISSION; UNITED STATES OF AMERICA, Respondents.

On Petition for Review of an Order of the Nuclear Regulatory Commission Argued and Submitted October 17, 2005-San Francisco, California Filed June 2, 2006 Before: Stephen Reinhardt and Sidney R. Thomas, Circuit Judges, and Jane A. Restani,* Chief Judge, United States Court of International Trade Opinion by Judge Thomas

• The Honorable Jane A. Restani, Chief Judge, United States Court of International Trade, sitting by designation.

6063

SAN Luis OBISPO MOTHERS V. NRC 6067 COUNSEL Diane Curran, Harmon, Curran, Spielberg & Eisenberg, L.L.P., Washington, D.C., for the petitioners.

Charles E. Mullins, United States Nuclear Regulatory Com-mission, Washington, D.C., for the respondents.

David A. Repka, Winston & Strawn, L.L.P., Washington, D.C., for respondent-intervenor PG&E.

Sheldon L. Trubatch, Esq., Offices of Robert K. Temple, Esq., Chicago, Illinois, for amicus San Luis Obispo County.

Kevin James, California Department of Justice, Oakland, Cal-ifornia, for amicus States of California, Massachusetts, Utah and Washington.

Jay E. Silberg, Shaw Pittman, L.L.P., Washington, D.C., for amicus Nuclear Energy Institute.

OPINION THOMAS, Circuit Judge:

This ease presents the question, inter alia, as to whether the likely environmental consequences of a potential terrorist

6068 SAN Luis OBIsPO MOTHERS V. NRC attack on a nuclear facility must be considered in an environ-mental review required under the National Environmental Policy Act. The United States Nuclear Regulatory Commis-sion ("NRC") contends that the possibility of a terrorist attack on a nuclear facility is so remote and speculative that the potential consequences of such an attack need not be consid-ered at all in such a review. The San Luis Obispo Mothers for Peace and other groups disagree and petition for review of the NRC's approval of a proposed Interim Spent Fuel Storage Installation. We grant the petition in part and deny it in part.

I The NRC is an independent federal agency established by the Energy Reorganization Act of 1974 to regulate the civilian use of nuclear materials. Intervenor Pacific Gas and Electric Company ("PG&E") filed an application with the NRC under 10 C.F.R. Part 72 for a license to construct and operate an Interim Spent Fuel Storage Installation ("Storage Installation" or "ISFSI") at PG&E's Diablo Canyon Power Plant ("Diablo Canyon") in San Luis Obispo, California. The NRC granted the license. The question presented by this petition for review is whether, in doing so, the NRC complied with federal stat-utes including the National Environmental Policy Act of 1969

("NEPA"), 42 U.S.C. §§ 4321-4437, the Atomic Energy Act of 1954 ("AEA"), 42 U.S.C. §§ 2011-2297g, and the Admin-istrative Procedure Act ("APA"), 5 U.S.C. §§ 551-706.

NEPA establishes a "national policy [to] encourage produc-tive and enjoyable harmony between man and his environ-ment," and was intended to reduce or eliminate environmental damage and to promote "the understanding of the ecological systems and natural resources important to" the United States.

Dept. of Transp. v. Pub. Citizen, 541 U.S. 752, 756 (2004)

(quoting 42 U.S.C. § 4321). The Supreme Court has identified NEPA's "twin aims" as "plac[ing] upon an agency the obliga-tion to consider every significant aspect of the environmental impact of a proposed action[, and] ensur[ing] that the agency

SAN Luis OBISPO MOTHERS V. NRC 6069 will inform the public that it has indeed considered environ-mental concerns in its decisionmaking process." Baltimore Gas & Elec. Co. v. Natural Res. Def. Counsel, Inc., 462 U.S.

87, 97 (1983).

Rather than mandating particular results, NEPA imposes on federal agencies procedural requirements that force consider-ation of the environmental consequences of agency actions.

Pub. Citizen, 541 U.S. at 756. At NEPA's core is the require-ment that federal agencies prepare an environmental impact statement ("EIS"), or:

include in every recommendation or report on pro-posals for legislation and other major Federal actions significantly affecting the quality of the human envi-ronment, a detailed statement by the responsible offi-cial on-(i) the environmental impact of the proposed action, (ii) any adverse environmental effects which cannot be avoided should the proposal be implemented, (iii) alternatives to the proposed action, (iv) the relationship between local short-term uses of man's environment and the maintenance and enhancement of long-term productivity, and (v) any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.

Id. at 757 (quoting 42 U.S.C. § 4332(2)(C)).

As an alternative to the EIS, an agency may prepare a more limited environmental assessment (EA"). concluding in a "Finding of No Significant Impact" ("FONSI"), briefly pre-senting the reasons why the action will not have a significant impact on the human environment. Id. at 757-58 (citing 40 C.F.R. §§ 1501.4(e), 1508.13).,If, however, the EA does not lead to the conclusion that a FONSI is warranted, the agency remains obligated to prepare an EIS. Id. at 757.

A 6070 SAN Luis OBISPO MOTHERS V. NRC While NEPA requires the NRC to consider environmental effects of its decisions, the AEA is primarily concerned with setting minimum safety standards for the licensing and opera-tion of nuclear facilities. The NRC does not contest that the two statutes impose independent obligations, so that compli-ance with the AEA does not excuse the agency from its NEPA obligations. The AEA lays out the process for consid-eration of the public health and safety aspects of nuclear power plant licensing, and requires the NRC to determine whether the licensing and operation of a proposed facility is "in accord with the common defense and security and will provide adequate protection to the health and safety of the public." 42 U.S.C. § 2232(a).

The NRC is not, however, required to make this deternina-tion without assistance; federal law provides a framework for hearings on material issues that interested persons raise by specific and timely petition. 42 U.S.C. § 2239(a); 10 C.F.R.

§§ 2.308-.348; 5 U.S.C. §§ 551-706. The initial hearing is held before a three-person Atomic Safety and Licensing Board ("Licensing Board"). 10 C.F.R. § 2.321. The Licensing Board's findings and decision constitute the agency's initial determination, although a party may file a petition for review with the Commission within 15 days of the Licensing Board's decision. 10 C.F.R. § 2.341. If the petition is granted, the Commission specifies the issues to be reviewed and the par-ties to the review proceedings, 10 C.F.R. § 2.341(c)(1), and renders a final decision. 10 C.F.R. § 2.344. A party may then petition this court for review of the Commission's final deci-sion. 28 U.S.C. § 2344.

II With this general statutory background, we turn to the facts underlying the petition for review. On December 21, 2001, PG&E applied to the NRC pursuant to 10 C.F.R. Part 72 for a license to construct and operate a Storage Installation at Diablo Canyon. The Storage Installation would permit the

SAN Luis OBISPO MOTHERS v. NRC 6071 necessary and on-site storage of spent fuel, the byproduct of the two nuclear reactors at that site. PG&E expects to fill its existing spent fuel storage capacity at Diablo Canyon some-time this year. Therefore, Unless additional spent fuel storage capacity is created, the Diablo Canyon reactors cannot con-tinue to function beyond 2006.

PG&E proposes to build a dry cask storage facility. The basic unit of the storage system is the Multi-Purpose Canister

("Canister"), a stainless steel cylinder that is filled with radio-active waste materials and welded shut. The Canisters are loaded into concrete storage overpacks that are designed to permit passive cooling via the circulation of air. The storage casks, or the filled Canisters loaded into overpacks, are then placed on one of seven concrete pads. The Storage Installation would house a total of 140 storage casks, 2 more than the 138 projected to be required for storage of spent fuel generated at Diablo Canyon through 2025.

On April 22, 2002, the NRC published a Notice of Oppor-tunity for Hearing. Under the regulatory scheme, interested parties could then request a hearing or petition for leave to intervene. 10 C.F.R. § 2.309(a). A written hearing request, which must contain the contentions the party wants litigated at the hearing, will be granted if the petitioner has standing, and has posed at least one admissible contention.1 Id.

On July 19, 2002, the San Luis Obispo Mothers for Peace, a non-profit corporation concerned with Diablo Canyon's 1

in order to be admissible, a contention must: be set forth with particu-larity, 10 C.F.R. § 2.309(0(1); provide a specific statement of the disputed issue of law or fact, 10 C.F.R. § 2.309(0(1)(i); provide the basis for the contention, 10 C.F.R. § 2.309(0(1)(ii); demonstrate that the issue is within the scope of the proceeding, 10 C.F.R. § 2.309(0(1)(iii); demonstrate that the issue is material to the findings the NRC must make, 10 C.F.R.

§ 2.309(0(1)(iv); provide supporting references and expert opinions, 10 C.F.R. § 2.309(0(1)(v); and provide sufficient information to show the existence of a genuine issue of law or fact, 10 C.F.R. § 2.309(f)(1)(vi).

6072 SAN LUIs OBISPO MOTHERS V. NRC local impact, the Sierra Club, a non-profit corporation con-cerned with national environmental policy, and Peg Pinard, an individual citizen, (collectively "Petitioners") submitted a hearing request and a petition to intervene, asserting conten-tions for admission.

In Licensing Board Proceeding LBP-02-23, 56 NRC 413

("LBP 02-23"), the Atomic Safety and Licensing Board addressed the admissibility of the July 19 petition's five Tech-nical and three Environmental Contentions.2 One Technical Contention, TC-1, dealing with the state of PG&E's finances, was deemed admissible; the acceptance of at least one conten-tion meant that the petition was granted. Although the Licens-ing Board deemed two Environmental Contentions, EC-1, dealing with the failure to address environmental impacts of terrorist or other acts of malice or insanity, and EC-3, dealing with the failure to evaluate environmental impacts of trans-portation of radioactive materials3 inadmissible, the Licensing Board nonetheless referred the final ruling as to the admissi-bility of these two contentions to the NRC, "in light of the 2

Technical Contention Number One ("TC-l") alleged Inadequate Seis-mic Analysis. TC-2 alleged PG&E's Financial Qualifications Are Not Demonstrated. TC-3 alleged PG&E May Not Apply for a License for a Third Party. TC-4 alleged Failure to Establish Financial Relationships Between Parties Involved in Construction and Operation of Installation.

TC-5 alleged Failure to Provide Sufficient Description of Construction and Operation Costs. Environmental Contention Number One ("EC-I")

alleged Failure to Address Environmental Impacts of Destructive Acts of Malice or Insanity. EC-2 alleged Failure to Fully Describe Purposes of Proposed Action or to Evaluate All Reasonably Associated Environmental Impacts and Alternatives. EC-3 alleged Failure to Evaluate Environmental Impacts of Transportation.

'Because the Storage Installation is not a permanent repository, this contention assumes the eventual transport of the materials stored there to a permanent site. Among the materials submitted to support the contention were some dealing with possible terrorist or other malicious attacks on the spent fuel while in transit. The ruling on the contention was "referr[ed]

... to the Commission to the extent terrorism and sabotage matters are proffered in support of its admission." 56 NRC at 453.

a SAN Luis OBISPO MOTHERS V. NRC 6073 Commission's ongoing 'top to bottom' review of the agency's safeguards and physical security programs." 56 NRC at 448.

In a memorandum and order, CLI-03-1, 57 NRC 1 ("CLI 03-01"), the NRC accepted the Licensing Board's referral of its decision to reject the environmental contentions related to terrorism. Although the Commission affirmed the Licensing Board's rejection of the contentions, it based its decision on a different rationale. The NRC relied on four prior decisions in which it held that the NEPA does not require a terrorism review. 4 These decisions, most particularly PrivateFuel Stor-age, CLI-02-25, 56 NRC 340 (2002), outlined four reasons for this holding: (1) the possibility of terrorist attack is too far removed from the natural or expected consequences of agency action to require study under NEPA; (2) because the risk of a terrorist attack cannot be determined, the analysis is likely to be meaningless; (3) NEPA does not require a "worst-case" analysis; and (4) NEPA's public process is not an appropriate forum for sensitive security issues. The NRC concluded:

Our decision today rests entirely on our understand-ing of NEPA and of what means are best suited to dealing with terrorism. Nonetheless, our conclusion comports with the practical realities of spent fuel storage and the congressional policy to encourage utilities to provide for spent fuel storage at reactor sites pending construction of a permanent repository.

Storage of spent fuel at commercial reactor sites offers no unusual technological challenges. Indeed, it has been occurring at Diablo Canyon for many 4Those cases include: PrivateFuelStorage,L.L. C., CLI-02-25, 56 NRC 340 (2002) (Storage Installation); Duke Cogema Stone & Webster (Mixed Oxide Fuel Fabrication Facility), CLI-02-24, 56 NRC 335 (2002); Domin-ion Nuclear Connecticut, Inc. (Nuclear Power Station), CLI-02-27, 56 NRC 367 (2002); and Duke Energy Corp. (Nuclear Power Station), CLI-02-26, 56 NRC 358 (2002). All four cases were decided on December 18, 2002.

i 6074 SAN Luis OISPO MOTHERS V. NRC years and will continue whether or not we license the proposed Installation.

57 NRC at 7.

In September of 2002, prior to the NRC's decision on the first petition, Petitioners submitted a second petition, this time requesting suspension of the Storage Installation licensing proceeding pending comprehensive review of the adequacy of Diablo Canyon's design and operation measures for protec-tion against terrorist attack and other acts of malice or insan-ity. Unlike the July 19 petition, this one addressed security measures for the entire Diablo Canyon complex, not merely the Storage Installation. Petitioners explained that 10 C.F.R.

§ 2.335, which prohibits challenges to any NRC rule or regu-lation in an adjudicatory proceeding involving initial or renewal licensing, prevented the raising of contentions con-testing the adequacy of NRC safety requirements protecting against terrorist or other malicious attacks on the entire com-plex in the July 19 Petition. Petitioners also stated that 10 C.F.R. § 72.32 prevented them from raising emergency plan-ning contentions in the earlier petition. Thus, Petitioners insisted that the second petition "d[id] not constitute a request for rulemaking, nor.., for enforcement action," and instead defined it, without reference to any particular hearing-granting provision of the regulations, as "a request for actions that are necessary to ensure that any licensing decision made by the Commission with respect to the proposed Diablo Can-yon Installation complies with the Commission's statutory obligations under the Atomic Energy Act."

In a memorandum and order, CLI-02-23, 56 NRC 230

("CLI 02-23"), the NRC denied the September 2002 petition.

Because the petition did not, according to the NRC, "fit com-fortably in any specific category, [the Commission] treat[ed]

it as a general motion brought under the procedural require-ments of 10 C.F.R. § 2.730."5 In rejecting the petition, the 5Since renumbered as 10 C.F.R. § 2.323, this regulation provides, sim-ply, for "motions".

SAN Luis OBISPO MOTHERS V. NRC 6075 Commission reasoned that by not suspending operating licenses at installations and power plants following the Sep-tember 11, 2001 terrorist attacks, it had demonstrated its implicit conclusion that the continued operation of these facil-ities neither posed an imminent risk to the public health, nor was inimical to the common defense. Further, the Commis-sion concluded that because it had already initiated a thorough review of its safeguards and physical security program, there was no reason to suspend the Diablo Canyon licensing pro-ceeding to address the terrorism-related concerns raised by the Petitioners. It stated that "[t]here certainly is no reason to believe that any danger to public health and safety would result from mere continuation of this adjudicatory proceed-ing," given that the proceeding was in its initial stages, that construction was not scheduled to begin for several years, and that the Petitioners would be able to comment on any changes in the rules resulting from the Commission's ongoing review of terrorism-related matters if and when they were to occur.

In a memorandum and order, CLI-03-12, 58 NRC 185 (2003) ("CLI 03-02"), the NRC denied the petitions for agency review of the Licensing Board's decisions that "cumu-latively, rejected challenges to [the PG&E] Installation appli-cation." This denial thus became a final order, reviewable by this court on petition for review. 28 U.S.C. § 2344.

In October of 2003, the Spent Fuel Project Office of the NRC's Office of Material Safety and Safeguards released its Environmental Assessment Related to the Construction and Operation of the Diablo Canyon Independent Spent Fuel Stor-age Installation. The 26-page document contains the NRC's conclusion "that the construction, operation, and decommis-sioning of the Diablo Canyon Installation will not result in significant impact to the environment," and therefore that "an

[EIS] is not warranted for the proposed action, and pursuant to 10 C.F.R. [§] 51.31, a Finding of No Significant Impact is appropriate."

6076 SAN Luis OBISPO MOTHERS v. NRC The EA is not devoid of discussion of terrorist attacks.

Indeed, the document contains the Commission's response to a comment submitted by the California Energy Commission in response to an earlier draft that "there is no discussion in the EA of the potential destruction of the casks or blockage of air inlet ducts as the result of sabotage or a terrorist attack

.. . [nor is there] a description of how decisions are being made regarding the configuration, design and spacing of the casks, the use of berms, and the location of the ISFSI to mini-mize the vulnerability of the ISFSI to potential attack." The NRC responded:

In several recent cases, ... the Commission has determined that an NRC environmental review is not the appropriate forum for the consideration of terror-ist acts. The NRC staff considers the security of spent fuel as part of its safety review of each applica-tion for an ISFSI license. In addition to reviewing an ISFSI application against the requirements of 10 CFR Part 72, the NRC staff evaluates the proposed security plans and facility design features to deter-mine whether the requirements in 10 CFR Part 73, "Physical Protection of Plants and Materials," are met. The details of specific security measures for each facility are Safeguards Information, and as such, can not be released to the public.

The NRC has also initiated several actions to fur-ther ensure the safety of spent fuel in storage. Addi-tional security measures have been put in place at nuclear facilities, including ISFSIs currently storing spent fuel. These measures include increased secur-ity patrols, augmented security forces and weapons, additional security posts, heightened coordination with law enforcement and military authorities, and additional limitations on vehicular access. Also, as part of its comprehensive review of its security pro-gram, the NRC is conducting several technical

SAN Luis OBIsPo MOTHERS V. NRC 6077 studies to assess potential vulnerabilities of spent fuel storage facilities to a spectrum of terrorist acts.

The results of these studies will be used to determine if revisions to the current NRC security requirements are warranted.

Petitioners argue that, in denying their petitions, the NRC violated the AEA, the APA, and NEPA. Although we reject the AEA and APA claims, we agree with Petitioners that the agency has failed to comply with NEPA. We have jurisdiction over those final orders of the NRC made reviewable by 42 U.S.C. § 2239, which includes final orders entered in licens-ing proceedings, under 28 U.S.C. § 2342(4).

III We turn first to Petitioners' AEA argument. Specifically, Petitioners argue that the NRC violated its regulations imple-menting the AEA, as well as the AEA's hearing provisions, when it denied Petitioners a hearing on whether NEPA required consideration of the environmental impact of a ter-rorist attack on the Storage Installation; they also argue that the NRC violated the AEA's hearing provisions in denying Petitioners a hearing on post-September 11 th security mea-sures for the entire Diablo Canyon complex. Both of these challenges fail.

A

[1] The NRC did not violate the AEA or its implementing regulations when it failed to explain its rejection of Petition-ers' contentions by addressing each of their arguments. Noth-ing in the regulations or the AEA requires the NRC to provide such an explanation.

Section 189(a) of the AEA grants public hearing rights "upon the request of any person whose interest may be affect-ed" by an NRC licensing proceeding. 42 U.S.C. § 2239. The

6078 SAN Luis OBISPO MOTHERS V. NRC NRC public hearing regulations, at 10 C.F.R. § 2.309, "pro-mulgated pursuant to the AEC's 6 power to make, promulgate, issue, rescind, and amend such rules and regulations as may be necessary to carry out the purposes of" the AEA, 12 U.S.C.

§ 2201(p), specify the procedures required of both petitioners and the NRC in making and deciding hearing petitions.

121 Petitioners correctly observe that the NRC, in its deci-sion, did not discuss whether Petitioners satisfied the regula-tory standard. They are mistaken, however, in their unsupported contention that this omission amounts to the agency's failure to follow its own regulations and thus is "re-versible error." The regulations simply do not require the NRC to explain its decisions in any particular manner.

Although the NRC regulations are specific and demanding in what they require of petitioners, they demand far less of the NRC in responding to a petition: the regulations require only a timely "decision." See 10 C.F.R. § 2.714(i) ("Decision on request/petition. The presiding officer shall, within 45 days after the filing of answers and replies .. . issue a decision on each request for hearing/petition to intervene."). Because Peti-tioners do not claim that the NRC violated this requirement, we must reject this challenge.

B 131 The NRC's denial of a hearing on whether NEPA requires consideration of the environmental effects of a terror-ist attack on the Storage Installation did not violate the AEA's hearing provisions.

[41 Petitioners contend that the NRC relied on an improper ground in denying their request for a hearing on whether 6in 1974, Congress eliminated the Atomic Energy Commission

("AEC"). Regulatory functions went to the NRC, and promotional func-tions to the Energy Research and Development Administration. See Energy Reorganization Act of 1974, 42 U.S.C. § 5814.

SAN Luis OBISPO MOTHERS V. NRC 6079 NEPA requires the Commission to consider the environmen-tal impacts of terrorism - namely, the ground that it had determined in earlier decisions that NEPA imposes no such obligation. Thus, Petitioners do not challenge the substantive validity or coherence of those earlier opinions in making their' AEA claim, but rather the reliance upon a prior determination of the merits in order to reject a petition presenting the same issues. As such, Sierra Club v. NRC, 862 F.2d 222 (9th Cir.

1988), on which Petitioners rely, does not apply. In that case, the NRC rejected the petitioners' contentions as lacking in reasonable specificity, and yet went on to analyze the merits of those supposedly unacceptable contentions. Id. at 228.

Here, however, where the agency is rejecting the contentions as contrary to a prior decision, the "merits" and the reason for the inadmissibility of the contention collapse. Put differently, the NRC did not reach the merits of the petition as much as it assessed the issues raised against issues resolved by prior decisions. We hold that in doing so, the Commission com-plied fully with the AEA. To hold otherwise would unduly restrict the agency's evaluation of hearing petitions, by requir-ing it to grant a hearing on issues it has already resolved whenever a petitioner claims to have new evidence. We can find, and Petitioners point to, nothing in the AEA that would require this result.

C

[51 The NRC's denial of a hearing on security measures for Diablo Canyon as a whole also did not violate the AEA. Peti-tioners argue that the AEA requires the NRC to grant petition-ers a hearing on all issues of material fact, including the security of the entire Diablo Canyon complex. Petitioners therefore conclude, citing Union of Concerned Scientists v.

NRC, 735 F.2d 1437 (D.C. Cir. 1984), that the NRC violated the AEA when it denied a hearing on that issue.

Petitioners' argument misreads Union of ConcernedScien-tists, in which the D.C. Circuit held only that the agency can-

J 6080 SAN Luis OBISPO MOTHERS V. NRC not by rule presumptively eliminate a material issue from consideration in a hearing petition. Union of Concerned Sci-entists requires the agency to consider a petition; it does not require that the agency grant it.

The NRC in CLI 02-23 did not deny that security require-ments for the entire complex might need to be upgraded, but rather maintained that a licensing proceeding hearing (and one regarding an installation, not the entire complex) was not the correct forum in which to address the issue. The Commission directed Petitioners to participate in a rulemaking or to raise their concerns in a hearing then pending before the Licensing Board. Petitioners contend that these alternative fora are illu-sory, and that rejection of their petition amounted to the denial of any opportunity to participate in the consideration of post-9/11 security measures for the Diablo Canyon complex.

Petitioners argue "[i]f the NRC were going to resolve Peti-tioners' concerns that grossly inadequate security made the Diablo Canyon facility vulnerable to terrorist attacks generi-cally, through a rulemaking, such a rulemaking would have been initiated as a result of the 'comprehensive security review' undertaken by the NRC." Thus, Petitioners argue that it would have been futile to submit a rulemaking petition.

This argument must fail, as Petitioners did not use the avail-able procedures for initiating a rulemaking. Petitioners cannot complain that NRC failed to institute a rulemaking they never requested.

16J Given that rulemaking may have been an avenue for Petitioners' participation, had they chosen to pursue it, their argument that they had no forum in which to raise their con-tentions loses its force. However, even were Petitioners cor-rect in their assertion that they were unfairly denied the opportunity to participate in a rulemaking proceeding, the argument that the Licensing Board hearing was similarly illu-sory would fail. In fact, Petitioners were attempting to use the present Storage Installation licensing proceeding as a means

SAN Luis OBISPO MOTHERS V. NRC 6081 of launching a much broader challenge to the Diablo Canyon complex. The NRC correctly observes that a petition alleging that existing NRC regulations are "grossly inadequate to pro-tect against terrorist attack, and therefore must be supple-mented by additional requirements" cannot in fact be raised before the Licensing Board, which cannot hear challenges to NRC rules. The limited scope of licensing proceedings does not, however, amount to the arbitrary denial of a forum, as Petitioners claim. While Petitioners could have raised site-specific issues "relating to the 'common defense and securi-ty' " that were not controlled by existing rules or regulations to the Licensing Board, they are not entitled to expand those proceedings to include the entire complex, and issues already covered by agency rules.

D In short, the NRC did not violate the AEA in denying the petitions for a hearing. Neither the AEA nor its implementing regulations required the NRC to grant Petitioners a hearing on whether NEPA required a consideration of the environmental impact of a terrorist attack on the Storage Installation or the security measures adopted for the entire Diablo Canyon com-plex.

IV

[7] The NRC's reliance on its own prior opinions in its decision in this case does not violate the APA's notice and comment provisions. Petitioners argue that the decisions in CLI 03-01 and PFS amount to the announcement "of a gen-eral policy of refusing to consider the environmental impacts of terrorist attacks in Environmental Impact Statements." Peti-tioners rely on Mada-Luna v. Fitzpatrick, 813 F.2d 1006, 1014 (9th Cir. 1987) to claim that this policy depends on fac-tual determinations not found subsequent to an evidentiary proceeding, and constitutes a "binding substantive norm," the promulgation of which, without a public hearing, violates the

Y 6082 SAN Luis OBISPO MOTHERS V. NRC APA notice and comment provisions contained in 5 U.S.C.

§§ 553(b), (c).' The flaw in Petitioners' argument is the mis-taken assertion that the NRC's decisions were factual and not legal. If the NRC's conclusion that terrorism need not be examined under NEPA were factual, then Petitioners would be correct that its determination would have to comply with APA rulemaking requirements, including notice and com-ment, or else the agency would have to permit petitioners to challenge it in every proceeding where it was disputed.

[81 That NEPA does not require consideration of the envi-ronmental impacts of terrorism is a legal, and not a factual, conclusion. Cf. GreenpeaceAction v. Franklin, 14 F.3d 1324, 1331 (9th Cir. 1993) (reasoning that a challenge to the ade-quacy of an EA turned on factual, not legal, principles where both NEPA's applicability and the requirements it imposed were uncontested); see also Alaska Wilderness Recreation &

Tourism Ass'n v. Morrison, 67 F.3d 723, 727 (9th Cir. 1995)

(noting that although "challenges to agency actions which raise predominantly legal, rather than technical questions, are rare," the court was there required to address "just such a challenge"). Petitioners' analysis is therefore inapposite. The agency has the discretion to use adjudication to establish a binding legal norm. See Sec. & Exch. Commn' v. Chenery, 332 U.S. 194, 199-203 (1947) ("[T]he choice made between proceeding by general rule or by individual, ad hoc litigation, is one that lies primarily in the informed discretion of the administrative agency."). We therefore agree with the NRC's characterization in its brief to this court: having come to the legal conclusion that NEPA does not require consideration of the environmental consequences of terrorist attacks, "[w]hen 7U.S.C. § 553(b) states that "[g]eneral notice of proposed rulemaking shall be published in the Federal Register," and outlines the requirements that such notice must meet. 5 U.S.C. § 553(c) states that after such notice has been given, "the agency shall give interested persons an opportunity to participate in the rulemaking through submission of written data, views, or arguments with or without opportunity for oral presentation."

T-SAN Luis OBIsPo MOTHERS V. NRC 6083 petitioners in this case presented a proposed contention seek-ing an EIS that analyzed the impacts of possible terrorist acts at the proposed Diablo Canyon Installation, the NRC reason-ably concluded that this request was sufficiently similar to the request in PFSto justify the application of that decision here."

V Although we hold that the agency did not violate the APA when it relied on the prior resolution of a legal issue through adjudication, we come to a different conclusion as to that determination's compliance with NEPA. Because the issue whether NEPA requires consideration of the environmental impacts of a terrorist attack is primarily a legal one, we review the NRC's determination that it does not for reason-ableness. See Alaska Wilderness Recreation & Tourism Ass 'n, 67 F.3d at 727 (reviewing predominately legal issue for rea-sonableness because "it makes sense to distinguish the strong level of deference we accord an agency in deciding factual or technical matters from that to be accorded in disputes involv-ing predominately legal questions"); Ka Makani'o Kohala Ohana, Inc. v. Water Supply, 295 F.3d 955, 959 n.3 (9th Cir.

2002) ("Because this case involved primarily legal issues...

based on undisputed historical facts, we conclude that the

'reasonableness' standard should apply to this case.").

Here, the NRC decided categorically that NEPA does not require consideration of the environmental effects of potential terrorist attacks. In making this determination, the NRC relied on PFS,where it "consider[ed] in some detail the legal ques-tion whether NEPA requires an inquiry into the threat of ter-rorism at nuclear facilities." 56 NRC 340, 343 (2002). In that case, intervenor State of Utah filed a contention claiming that the September 11 terrorist attacks "had materially changed the circumstances under which the Board had rejected previously proffered terrorism contentions by showing that a terrorist attack is both more likely and potentially more dangerous than previously thought." Id. at 345. The NRC concluded that

6084 SAN Luis OBISPO MOTHERS v. NRC even following the September 11th attacks, NEPA did not impose such a requirement, reasoning:

In our view, an EIS is not an appropriate format to address the challenges of terrorism. The purpose of an EIS is to inform the decisionmaking authority and the public of a broad range of environmental impacts that will result, with a fair degree of likelihood, from a proposed project, rather than to speculate about

'worst-case' scenarios and how to prevent them.

Id. at 347.

The NRC determined that four grounds "cut[ ] against using the NEPA framework" to consider the environmental effects of a terrorist attack: (1) the possibility of a terrorist attack is far too removed from the natural or expected conse-quences of agency action; (2) because the risk of a terrorist attack cannot be determined, the analysis is likely to be mean-ingless; (3) NEPA does not require a "worst-case" analysis; and (4) NEPA's public process is not an appropriate forum for sensitive security issues. Id. at 348. We review each of these four grounds for reasonableness, and conclude that these grounds, either individually or collectively, do not support the NRC's categorical refusal to consider the environmental effects of a terrorist attack.

A

[9] The Commission relied first on finding that the possibil-ity of a terrorist attack is too far removed from the natural or expected consequences of agency action. Id. at 347. Section 102 of NEPA requires federal agencies to prepare "a detailed statement... on the environmental impact" of any proposed major federal action "significantly affecting the quality of the human environment." 42 U.S.C. § 4332(l)(C)(i). The ques-tion thus becomes whether a given action "significantly affects" the environment.

SAN Luis OBISPO MOTHERS V. NRC 6085 The NRC claims that the appropriate analysis of Section 102 is that employed by the Supreme Court in Metropolitan Edison Co. v. People Against Nuclear Power, 460 U.S. 766, 773 (1983). In MetropolitanEdison, the Court noted that "[t]o determine whether Section 102 requires consideration of a particular effect, we must look to the relationship between that effect and the change in the physical environment caused by the major federal action at issue," looking for "a reason-ably close causal relationship .. . like the familiar doctrine of proximate cause from tort law." 460 U.S. at 774. The Com-mission claims that its conclusion that the environmental impacts of a possible terrorist attack on an NRC-licensed facility is beyond a "reasonably close causal relationship" was a reasonable application of this "proximate cause" analogy.

The problem with the agency's argument, however, is that Metropolitan Edison and its proximate cause analogy are inapplicable here. In Metropolitan Edison, the petitioners argued that NEPA required the NRC to consider the potential risk of psychological damage upon reopening the Three Mile Island nuclear facilities to those in the vicinity. Noting that NEPA is an environmental statute, the Supreme Court held that the essential analysis must focus on the "closeness of the relationship between the change in the environment and the

'effect' at issue." 460 U.S. at 772.

The appropriate analysis is instead that developed by this court in NoGwen Alliance v. Aldridge, 855 F.2d 1380 (9th Cir. 1988). In NoGwen, the plaintiffs argued that NEPA required the Air Force to consider the threat of nuclear war in the implementation of the Ground Wave Emergency Network

("GWEN"). We held "that the nexus between construction of GWEN and nuclear war is too attenuated to require discussion of the environmental impacts of nuclear war in an [EA] or

[EIS]." 855 F.2d at 1386.

1101 The events at issue here, as well as in Metropolitan Edison and NoGwen, form a chain of three events: (1) a major

S. . 1 6086 SAN Luis OBISPO MOTHERS V. NRC federal action; (2) a change in the physical environment; and (3) an effect. Metropolitan Edison was concerned with the relationship between events 2 and 3 (the change in the physi-cal environment, or increased risk of accident resulting from the renewed operation of a nuclear reactor, and the effect, or the decline in the psychological health of the human popula-tion). The Court in Metropolitan Edison explicitly distin-guished the case where the disputed relationship is between events I and 2: "we emphasize that in this case we are consid-ering effects caused by the risk of accident. The situation where an agency is asked to consider effects that will occur if a risk is realized, for example, if an accident occurs ... is an entirely different case." Id. at 775 n.9. In NoGwen, we fol-lowed the Court's admonition and, in addressing the relation-ship between events 1 and 2, we held that the Metropolitan Edison analysis did not apply "because it discusse[d] a differ-ent type of causation than that at issue in this case... [which]

require[d] us to examine the relationship between the agency action and a potential impact on the environment." Id. at 1386. NoGWEN relied on our decision in Warm Springs Dam Task Force v. Gribble, 621 F.2d 1017, 1026 (9th Cir. 1980),

which held that "an impact statement need not discuss remote and highly speculative consequences." Applying that standard to the plaintiffs' claims that the military GWEN system's installation would "increase the probability of nuclear war,"

and "that GWEN would be a primary target in a nuclear war,"

we held both propositions to be "remote and highly specula-tive," and, therefore, NEPA did not require their consider-ation.

1111 In the present case, as in NoGwen, the disputed rela-tionship is between events 1 and 2 (the federal act, or the licensing of the Storage Installation, and the change in the physical environment, or the terrorist attack). The appropriate inquiry is therefore whether such attacks are so "remote and highly speculative" that NEPA's mandate does not include consideration of their potential environmental effects.

• r SAN Luis OBISPO MOTHERS V. NRC 6087

[12] The NRC responds by simply declaring without sup-port that, as a matter of law, "the possibility of a terrorist attack.., is speculative and simply too far removed from the natural or expected consequences of agency action to require a study under NEPA." 56 NRC at 349. In doing so, the NRC failed to address Petitioners' factual contentions that licensing the Storage Installation would lead to or increase the risk of a terrorist attack because (1) the presence of the Storage Installation would increase the probability of a terrorist attack on the Diablo Canyon nuclear facility, and (2) the Storage Installation itself would be a primary target for a terrorist attack. We conclude that it was unreasonable for the NRC to categorically dismiss the possibility of terrorist attack on the Storage Installation and on the entire Diablo Canyon facility as too "remote and highly speculative" to warrant consider-ation under NEPA.

[13] In so concluding, we also recognize that the NRC's position that terrorist attacks are "remote and highly specula-tive," as a matter of law, is inconsistent with the government's efforts and expenditures to combat this type of terrorist attack against nuclear facilities. In the PFS opinion, the NRC emphasized the agency's own post-September I Ith efforts against the threat of terrorism:

At the outset, however, we stress our determination, in the wake of the horrific September 1 th terrorist attacks, to strengthen security at facilities we regu-late. We currently are engaged in a comprehensive review of our security regulations and programs, act-ing under our AEA-rooted duty to protect "public health and safety" and the "common defense and security." We are reexamining, and in may cases have already improved, security and safeguards mat-ters such as guard force size, physical security exer-cises, clearance requirements and background investigations for key employees, and fitness-for-duty requirements. More broadly, we are rethinking

6088 SAN Luis OBISPO MOTHERS v. NRC the NRC's threat assessment framework and design basis threat. We also are reviewing our own infra-structure, resources, and communications.

Our comprehensive review may also yield perma-nent rule or policy changes that will apply to the pro-posed PFS facility and to other NRC-related facilities. The review process is ongoing and cumu-lative. It has already resulted in a number of security-related actions to address terrorism threats at both active and defunct nuclear facilities.

56 NRC at 343. Among these actions is the establishment of an Office of Nuclear Security and Incident Response, "re-sponsible for immediate operational security and safeguards issues as well as for long-term policy development[,] work[-

ing] closely with law enforcement agencies and the Office of Homeland Security[,] ... coordinat[ing] the NRC's ongoing comprehensive security review." Id. at 344-45.

We find it difficult to reconcile the Commission's conclu-sion that, as a matter of law, the possibility of a terrorist attack on a nuclear facility is "remote and speculative," with its stated efforts to undertake a "top to bottom" security review against this same threat. Under the NRC's own formulation of the rule of reasonableness, it is required to make determina-tions that are consistent with its policy statements and proce-dures. Here, it appears as though the NRC is attempting, as a matter of policy, to insist on its preparedness and the serious-ness with which it is responding to the post-September 11 th terrorist threat, while concluding, as a matter of law, that all terrorist threats are "remote and highly speculative" for NEPA purposes.!

'The view that a terrorist attack is too speculative to be a required part of NEPA review would seem to be inconsistent with the NRC's pre-9/l I security procedures. Since 1977, the NRC has required licensed plants to have a security plan that is designed to protect against a "design basis

• r 1 SAN Luis OBisPo MOTHERS V. NRC 6089

[141 In sum, in considering the policy goals of NEPA and the rule of reasonableness that governs its application, the possibility of terrorist attack is not so "remote and highly speculative" as to be beyond NEPA's requirements.

B f151 The NRC's reliance upon the second PFS factor, that the Risk of a Terrorist Attack Cannot be Adequately Deter-mined, 56 NRC at 350, is also not reasonable. First, the NRC's dismissal of the risk of terrorist attacks as "unquantifi-able" misses the point. The numeric probability of a specific attack is not required in order to assess likely modes of attack, weapons, and vulnerabilities of a facility, and the possible impact of each of these on the physical environment, includ-ing the assessment of various release scenarios. Indeed, this is precisely what the NRC already analyzes in different con-texts. It is therefore possible to conduct a low probability-high consequence analysis without quantifying the precise proba-bility of risk. The NRC itself has recognized that consider-ation of uncertain risks may take a form other than quantitative "probabilistic" assessment. In its "Proposed Pol-icy Statement on Severe Accidents and Related Views on Nuclear Reactor Regulation," 48 Fed.Reg. 16,014 (1983), the Commission stated that:

threat" for radiological sabotage. See General Accounting Office, Nuclear Regulatory Commission: Oversight of Security at Commercial Nuclear Power Plants Needs to be Strengthened, GAO-030752 (2003) at 6. "The design basis threat characterizes the elements of a postulated attack, including the number of attackers, their training, and the weapons and tac-tics they are capable of using." Id.

Thus, the NRC-even before the terrorist attacks of 9/11--did not con-sider such attacks too "remote and speculative" to be considered in agency planning. To the contrary, the agency has long required analysis of means and methods of hypothetical attacks against specific facilities, with the goal of establishing effective counter-measures.

6090 SAN Luis OBISPO MOTHERS v. NRC In addressing potential accident initiators (including earthquakes, sabotage, and multiple human errors) where empirical data are limited and residualuncer-tainty is large, the use of conceptual modeling and scenario assumptions in Safety Analysis Reports will be helpful. They should be based on the best quali-fiedjudgments of experts, either in the form of sub-jective numerical probability estimates or qualitative assessments of initiating events and casual [sic]

linkages in accident sequences.

48 Fed.Reg. at 16,020 (emphasis added).

[161 No provision of NEPA, or any other authority cited by the Commission, allows the NRC to eliminate a possible envi-ronmental consequence from analysis by labeling the risk as "unquantifiable." See Limerick Ecology Action, Inc. v. NRC, 869 F.2d 719, 754 (3rd Cir. 1989) (J. Scirica, dissenting)

(finding no "statutory provision, no NRC regulation or policy statement, and no case law that permits the NRC to ignore any risk found to be unquantifiable"). If the risk of a terrorist attack is not insignificant, then NEPA obligates the NRC to take a "hard look" at the environmental consequences of that risk. The NRC's actions in other contexts reveal that the agency does not view the risk of terrorist attacks to be insig-nificant. Precise quantification is therefore beside the point.

Even if we accept the agency's argument, the agency fails to adequately show that the risk of a terrorist act is unquantifi-able. The agency merely offers the following analysis as to the quantifiability of a potential terrorist attack:

The horrors of September 11 notwithstanding, it remains true that the likelihood of a terrorist attack being directed at a particular nuclear facility is not quantifiable. Any attempt at quantification or even qualitative assessment would be highly speculative.

In fact, the likelihood of attack cannot be ascertained

.6 It-SAN Luis OBISPO MOTHERS V. NRC 6091 with confidence by any state-of-the-art methodology.

That being the case, we have no means to assess, usefully, the risks of terrorism at the PFS facility.

56 NRC at 350. The agency nonetheless has simultaneously shown the ability to conduct a "top to bottom" terrorism review. This leaves the Commission in the tenuous position of insisting on the impossibility of a meaningful, i.e. quantifi-able, assessment of terrorist attacks, while claiming to have undertaken precisely such an assessment in other contexts.

Further, as we have noted, the NRC has required site-specific analysis ofsuch threats, involving numerous recognized scenar-ios.

1171 Thus, we conclude that precise quantification of a risk is not necessary to trigger NEPA's requirements, and even if it were, the NRC has not established that the risk of a terrorist attack is unquantifiable.

C The NRC's third ground, that it is not required to conduct a "worst-case" analysis, is a non sequitur. Although it is a true statement of the law, the agency errs in equating an assess-ment of the environmental impact of terrorist attack with a demand for a worst-case analysis.

The Council on Environmental Quality ("CEQ") regula-tions, 40 C.F.R. §§ 1500.1 - 1518.4, promulgated with the "purpose [of] tell[ing] federal agencies what they must do to comply with [NEPA] procedures and achieve the goals of OThe NRC's assertion that a risk of terrorism cannot be quantified is also belied by the very existence of the Department of Homeland Security Advisory System, which provides a general assessment of the risk of ter-rorist attacks. See, e.g., World Market Research Centre, Global Terrorism Index 2003/4 (offering a probabilistic risk assessment of terrorist activities over a 12-month period).

, .-6 6092 SAN Luis OBISPO MOTHERS v. NRC

[NEPA]," have been interpreted by the Supreme Court as "en-titled to substantial deference." Robertson v. Methow Valley Citizens Council, 490 U.S. 332, 355 (citing Andrus v. Sierra Club, 442 U.S. 347, 358 (1979)). These regulations mandated worst-case analyses until 1986, when CEQ replaced the for-mer 40 C.F.R. § 1502.22, requiring an agency, when relevant information was either unavailable or too costly to obtain, to include in the EIS a "worst-case analysis and an indication of the probability or improbability of its occurrence," with the new and current version of the regulation, which requires an agency to instead deal with uncertainties by including within the EIS "a summary of existing credible scientific evidence which is relevant to evaluating the reasonable foreseeable sig-nificant adverse impacts on the human environment, and...

the agency's evaluation of such impacts based upon theoreti-cal approaches or research methods generally accepted in the scientific community." 40 C.F.R. §§ 1502.22(b)(3), (4). The current requirement applies to those events with potentially catastrophic consequences "even if their probability of occur-rence is low, provided that the analysis of impacts is sup-ported by credible scientific evidence, is not based on pure conjecture, and is within the rule of reason." 40 C.F.R.

§ 1502.22 (b)(4). The Supreme Court held in Robertson that the amendment of the regulations had nullified the worst-case analysis requirement. 490 U.S. at 355; Edwardsen v. U.S.

Dep't of Interior,268 F.3d 781, 785 (9th Cir. 2001).

The Commission is therefore correct when it argues that NEPA does not require a worst-case analysis. It is mistaken, however, when it claims that "Petitioners' request for an anal-ysis of [the environmental effects of] a successful terrorist attack at the Diablo Canyon ISFSI approximates a request for a 'worst-case' analysis that has long since been discarded by the CEQ regulations . . . and discredited by the Federal courts." According to the NRC, "[m]aking the various assumptions required by [P]etitioners' scenario requires the NRC to venture into the realm of 'pure conjecture.' "We dis-agree.

i - T A1 SAN Luis OBISPO MOTHERS V. NRC 6093

[18] An indication of what CEQ envisioned when it imposed the worst-case analysis requirement can be gleaned from a 1981 CEQ memorandum, Forty Most Asked Questions Concerning CEQ's National Environmental Policy Act Regu-lations, reprinted at 46 FR 18026-01 (March 23, 1981). CEQ answered one of those questions, "[w]hat is the purpose of a worst-case analysis? How is it formulated and what is the scope of the analysis?" with the following:

The purpose of the analysis is to . . . cause agencies to consider th[ ]e potential consequences [of agency decisions] when acting on the basis of scientific uncertainties or gaps in available information. The analysis is formulated on the basis of available infor-mation, using reasonable projections of the worst possible consequences of a proposed action.

For example, if there are scientific uncertainty and gaps in the available information concerning the numbers of juvenile fish that would be entrained in a cooling water facility, the responsible agency must disclose and consider the possibility of the loss of the commercial or sport fishery. In addition to an analysis of a low probability/catastrophic impact event, the worst-case analysis should also include a spectrum of events of higher probability but less drastic impact.

46 FR 18026, 18032. While it is true that the agency is not required to consider consequences that are "speculative,""1 the 1

"Because we disagree with the agency's interpretation of worst-case analysis, we do not reach the agency's characterization of the possibility of terrorist attack as "speculative." We note, however, that this character-ization stands out as contrary to the vigilant stance that Americans are encouraged to take by the Department of Homeland Security. See www.dhs.gov/dhspublic/display?theme=29 (urging that "[a]ll Americans should continue to be vigilant" and noting that "[tlhe country remains at an elevated risk ... for terrorist attack.")

A t 6094 SAN Luis OBisPo MOTHERS V. NRC NRC's argument wrongly labels a terrorist attack the worst-case scenario because of the low or indeterminate probability of such an attack. The CEQ memo, by including as worst-case scenarios events of both higher and lower probability, reveals that worst-case analysis is not defined solely by the low prob-ability of the occurrence of the events analyzed, but also by the range of outcomes of those events. See also Greater Yel-lowstone Coalition v. Flowers, 321 F.3d 1250, 1260 (10th Cir. 2003) (citing a witness's testimony that the loss of bald eagle nesting sites was both "likely" and "a worst-case sce-nario"). Petitioners do not seek to require the NRC to analyze the most extreme (i.e., the "worst") possible environmental impacts of a terrorist attack. Instead, they seek an analysis of the range of environmental impacts likely to result in the event of a terrorist attack on the Storage Installation. We reject the Commission's characterization of this request as a demand for a worst-case analysis.

D 1191 The NRC's reliance on the fourth PFS factor, that it cannot comply with its NEPA mandate because of security risks, is also unreasonable. There is no support for the use of security concerns as an excuse from NEPA's requirements.

While it is true, as the agency claims, that NEPA's require-ments are not absolute, and are to be implemented consistent with other programs and requirements, this has never been interpreted by the Supreme Court as excusing NEPA's appli-cation to a particularly sensitive issue. See Weinberger v.

Catholic Action ofHawaii, 454 U.S. 139 (1981) (holding that the Navy was required to perform a NEPA review and to fac-tor its results into decisionmaking even where the sensitivity of the information involved meant that the NEPA results could not be publicized or adjudicated). Weinberger can sup-port only the proposition that security considerations may per-mit or require modification of some of the NEPA procedures, not the Commission's argument that sensitive security issues result in some kind of NEPA waiver.

' 1 A SAN Luis OBISPO MOTHERS V. NRC 6095 The application of NEPA's requirements, under the rule of reason relied on by the NRC, is to be considered in light of the two purposes of the statute: first, ensuring that the agency will have and will consider detailed information concerning significant environmental impacts; and, second, ensuring that the public can both contribute to that body of information, and can access the information that is made public. Pub. Citizen, 541 U.S. at 768. To the extent that, as the NRC argues, certain information cannot be publicized, as in Weinberger, other statutory purposes continue to mandate NEPA's application.

For example, that the public cannot access the resulting infor-mation does not explain the NRC's determination to prevent the public from contributinginformation to the decisionmak-ing process. The NRC simply does not explain its unwilling-ness to hear and consider the information that Petitioners seek to contribute to the process, which would fulfill both the information-gathering and the public participation functions of NEPA. These arguments explain why a Weinberger-style limited proceeding might be appropriate, but cannot support the NRC's conclusion that NEPA does not apply. As we stated in NoGWEN: "There is no 'national defense' exception to NEPA . . . 'The Navy, just like any federal agency, must carry out its NEPA mandate to the fullest extent possible and this mandate includes weighing the environmental costs of the

[project] even though the project has serious security implica-tions.'" 855 F.2d at 1384 (quoting ConcernedAbout Trident

v. Rumsfeld, 555 F.2d 817, 823 (D.C. Cir. 1977)).

E 1201 In sum, none of the four factors upon which the NRC relies to eschew consideration of the environmental effects of a terrorist attack satisfies the standard of reasonableness. We must therefore grant the petition in part and remand for the agency to fulfill its responsibilities under NEPA.

[21] Our identification of the inadequacies in the agency's NEPA analysis should not be construed as constraining the

I. ,.~

6096 SAN Luis OBISPO MOTHERS V. NRC NRC's consideration of the merits on remand, or circumscrib-ing the procedures that the NRC must employ in conducting its analysis. There remain open to the agency a wide variety of actions it may take on remand, consistent with its statutory and regulatory requirements. We do not prejudge those alter-natives. Nor do we prejudge the merits of the inquiry. We hold only that the NRC's stated reasons for categorically refusing to consider the possibility of terrorist attacks cannot withstand appellate review based on the record before us.

We are also mindful that the issues raised by the petition may involve questions of national security, requiring sensitive treatment on remand. However, the NRC has dealt with our nation's most sensitive nuclear secrets for many decades, and is well-suited to analyze the questions raised by the petition in an appropriate manner consistent with national security.

VI We deny the petition as to the claims under the AEA and the APA. However, because we conclude that the NRC's determination that NEPA does not require a consideration of the environmental impact of terrorist attacks does not satisfy reasonableness review, we hold that the EA prepared in reli-ance on that determination is inadequate and fails to comply with NEPA's mandate. We grant the petition as to that issue and remand for further proceedings consistent with this opin-ion.

PETITION GRANTED IN PART; DENIED IN PART; REMANDED.

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE COMMISSION In the Matter of )

)

Entergy Nuclear Operations, Inc. ) Docket No. 50-293

)

(Vermont Yankee Nuclear Power Station) )

MASSACHUSETTS ATTORNEY GENERAL'S REQUEST FOR A HEARING AND PETITION FOR LEAVE TO INTERVENE WITH RESPECT TO ENTERGY NUCLEAR OPERATIONS INC.'S APPLICATION FOR RENEWAL OF THE VERMONT YANKEE NUCLEAR POWER PLANT OPERATING LICENSE AND PETITION FOR BACKFIT ORDER REQUIRING NEW DESIGN FEATURES TO PROTECT AGAINST SPENT FUEL POOL ACCIDENTS By Massachusetts Attorney General Thomas F. Reilly Through his Attorneys, Diane Curran Harmon Curran, Spielberg & Eisenberg, L.L.P.

1726 M Street N.W., Suite 600 Washington, D.C. 20036 202/328-3500 dcurran(@harmoneurran.com Matthew Brock, Assistant Attorney General Environmental Protection Division Office of the Attorney General One Ashburton Place Boston, MA 02108 617/727-2200 matthew.brock@ago.state.ma.us May 26, 2006

TABLE OF CONTENTS

1. INTRODUCTION AND EXECUTIVE

SUMMARY

.............................. I II. THE MASSACHUSETTS ATTORNEY GENERAL HAS STANDING TO INTERVENE IN THIS PROCEEDING AND REQUEST A BACKFIT ORDER ................................................................... 4 III. STATUTORY AND REGULATORY FRAMEWORK ........................... 5 A. Atomic Energy Act Safety Requirements .................................... 6

1. AEA requirements for protection of public safety .................. 6

2. NRC requirements for protection against design-basis Accidents ................................................................. 7

3. Standard for license renewal .......................................... 8 B. NEPA Statutory and Regulatory Requirements ............................. 9

1. General NEPA requirements .......................................... 9

a. NEPA requirement to prepare an EIS ...................... 9

b. NEPA requirement to supplement an EIS ................ 10 C. NEPA requirement that an EIS must consider reasonably foreseeable impacts of nuclear accidents ................. 10

2. NRC's procedures for preparation of ER and EIS ................ 11

3. NRC's NEPA procedures for license renewal ................... 12

a. NRC reliance on License Renewal GElS in individual license renewal proceedings ............................... 12

b. NRC discussion of accident impacts in License Renewal G EIS ............................................................ 13

c. NRC requirement to supplement License Renewal G EIS ............................................................ 15

d. NRC requirement to consider alternatives in site-specific ER and EIS ..................................... 15 C. Atomic Energy Act Public Hearing Requirements for License Renewal D ecisions ................................................................ 16 IV. FACTUAL AND PROCEDURAL BACKGROUND ................................ 18 A. Vermont Yankee Nuclear Power Plant ...................................... 18

1. Pool Storage of Spent Fuel at Vermont Yankee .................. 18

2. Availability of dry storage as an alternative to pool storage ....... 20 ii

B. Vermont Yankee license renewal application ............................. 20 V. CONTENTION: THE ENVIRONMENTAL REPORT FOR THE VERMONT YANKEE NUCLEAR POWER PLANT FAILS TO SATISFY NEPA BECAUSE IT DOES NOT ADDRESS THE ENVIRONMENTAL IMPACTS OF SEVERE SPENT FUEL POOL ACCIDENTS .................. 21 A. Contention .......................................................................... 21 B. Basis for Contention .......................................................... 23

1. The potential for a pool fire has not been considered in any previous EIS ............................................................ 24

a. The EIS for original Vermont Yankee license and other nuclear power plant licenses did not consider impacts of pool accidents ................................................. 25

b. The 1979 Sandia Report showed risks of high-density pool storage ................................................... 26

c. The 1979 GEIS did not address pool fire risks ....... 26

d. The 1990 Waste Confidence rulemaking ignored the risk of pool fires ................................................... 27

c. The License Renewal GElS merely repeated the inadequate analysis in the 1990 Waste Confidence rulemaking ........ 28

2. Only the 1979 GElS has evaluated the environmental Impacts of deliberate and malicious acts against spent fuel pools ............................................................... 29

3. Significant new information shows the reasonably foreseeable potential for a pool fire, and that the consequences are high ....... 30

a. Significant new information shows that fuel of any age will bum if uncovered ............................. 30

b. Significant new information shows the credibility of events leading to a fuel pool accident .................. 32

i. Accidents caused by human error, equipment failure, and natural forces are credible ............... 32 iii

ii. Accidents caused by intentional malicious acts are credible .......................................... 33 iii. Fuel pools are vulnerable to attack ................. 36 C. The NRC has adequate qualitative tools to evaluate the potential for intentional malicious acts against the Vermont Yankee plant ....................................... 37

d. Other GElS grounds for refusing to address impacts of deliberate and malicious acts are invalid ................. 40

e. NRC's policy rationales in PFSH and Diablo Canyon are not supported ............................................. 42

4. The consequences of a pool fire are different and potentially more serious than the consequences of a reactor accident ..... 47

5. The ER and EIS should consider the SAMA of combined low-density pool storage and dry storage ............................... 47 VI. PETITION FOR IMPOSITION OF BACKFIT ORDER ............................. 48 VII. CONCLUSION .......................................................................... 50 iv

TABLE OF AUTHORITIES Judicial Decisions Citizensfor Safe Power v. NRC, 524 F.2d 1291(D.C. Cir. 1975) ........................ 5 FlintRidge Development Corp. v. Scenic Rivers Association of Oklahoma, 426 U.S. 776 (1976) .................................................... 44 Hodges v. Abraham, 300 F.3d 432 (4th Cir. 2002) .......................................... 24 Hughes River Watershed Conservancy v. Agriculture Dept.,

81 F.3d 437 (4th Cir. 1996) ........................................................................ 27 Idaho ConservationLeague v. Mumma, 956 F.2d 1508 (9" Cir. 1992) ............ 47 Limerick Ecology Action v. NRC, 869 F.2d 719, 729-30 (3 rd Cir. 1989) ............... passim Marsh v. Oregon NaturalResources Council, 490 U.S. 374 (1989) .......... 2, 4, 10, 15, 27 MetropolitanEdison Co. v. People Against Nuclear Energy, 460 U.S. 766 (1983) ....... 43 Power Reactor Development Corp. v. InternationalUnion ofElectrical Radio and Machine Workers, 367 U.S. 396 (1961) ....................................... 6, 8,48 Public Service Co. of New Hampshirev. NRC, 582 F.2d 77 (1"t Cir.),

cert. denied,439 U .S. 1046 (1978) ............................................................... 44 Robertson v. Methow Valley Citizens Council (Robertson), 490 U.S. 332 (1989)..'....8, 26 Sierra Club v. NRC, 862 F.2d 222 (9b Cir. 1988) .......................................... 42 Southwest Center v. U.S. ForestService, 100 F.3d 1443 (9h Cir. 1996) ............... 42 Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U.S. 519 (1978) ................................................. 10 NRC Decisions Amergen Energy Company, L.L.C. (License Renewal for Oyster Creek Nuclear Generating Station), LBP-06-07, __ NRC _ (February 27, 2006) ............................ 4 CarolinaPower & Light Co. (Shearon Harris Nuclear Power Plant),

CLI-01-11, 53 N RC 370 (2001), .............................................................. 11,24 CarolinaPower & Light Co. (Shearon Harris Nuclear Power Plant),

LBP-00-19, 52 NRC 85 (2000), affirmed on other grounds, V

CLI-01-1 1, 53 NRC 370 (2001) ............................................................... 23 CarolinaPower & Light Co. (Shearon Harris Nuclear Power Plant),

LBP-01-09, 53 NRC239 (2000), affirmed, CLI-01-1 1, 53 NRC 370 (2001) ............ 24 Consumers Power Co. (Big Rock Point Plant), LBP-84-32, 20 NRC 601 (1984) ........... 7 Dominion Nuclear Connecticut,Inc. (Millstone Nuclear Power Station,Unit 1, CLI 27, 56 NRC 367 (2002) .......................................................................... 15 Duke CogemaStone and Webster (Savannah River Mixed Oxide Fuel Fabrication Facility), CLI-02-24, 56 NRC 335 (2002) ....................................................... 34 Duke Cogema Stone and Webster (Savannah River Mixed Oxide Fuel Fabrication Facility), LBP-01-35, 54 NRC 403 (2001), reversed, CLI-02-24, 56 NRC 335 (2002) .......................................................... 15, 33-34 Duke Energy Corp.*(McGuire Nuclear Station, Units I and 2), Catawba Nuclear Station, Units 1 and 2), CLI-02-26, 56 NRC 358 (2002) ............................................. 15 Duke Energy Corporation(McGuire Nuclear Station, Units I and 2; Catawba Nuclear Station, Units 1 and 2), CLI-02-14, 55 NRC 278 (2002) ............. 14 Duke Power Co. (Catawba Nuclear Station, Units I and 2), CLI-83-19, 17 NRC 1041 (1983) ............................................................................ 12 FloridaPower & Light Co. (Turkey Point Nuclear Generating Plant, Units 3 and 4), CLI-01-17, 54 NRC 3 (2001) ............................................... 13 MetropolitanEdison Co. (Three Mile Island Nuclear Station, Unit 2),

ALAB-692, 16 NRC 921 (1982) ............................................................... 7 Pacific Gas & Electric Company (Diablo Canyon Nuclear Power Plant),

ALAB-410, 5 NRC 1398, 1405 (1977) ...................................................... 45 Pacific Gas & Electric Company (Diablo Canyon ISFSI),

CLI-03-12, 58 NRC 185 (2003)...................................................... 13-14,41-43 Petitionfor Emergency and Remedial Action, CLI-78-6, 7 N RC 400 (1978).............................................................................. 4, 8, 48 PhiladelphiaElectric Co. (Limerick Generating Station, Units 1 and 2),

ALAB-819, 22 NRC 681(1985) ("LimerickAppeal BoardDecision'),

aff'd on this ground and rev 'd on othergrounds, Limerick Ecology Action v. NRC, 869 F.2d 719, 743-44 (3"' Cir. 1989) ...................................... 14 PrivateFuel Storage, L.L.C. (Independent Spent Fuel Storage Installation),

Vi

CLI-01-22, 54 NRC 255 (2001) ....................................................... 7, 33, 48, 49 PrivateFuel Storage, L.L.C. (Independent Spent Fuel Storage Installation, CLI-02-25, 56 NRC 340 (2002) ...................................................... 13, 35, 41-43 Vermont Yankee Nuclear Power Corp. (Vermont Yankee Nuclear Power Station), CLI-90-7, 32 NRC 129 (1990) ............................................. 10 Vermont Yankee Nuclear Power Corp. (Vermont Yankee Nuclear Power Station), CLI-90-4, 31 NRC 333 (1990) ...................................................... 7 Vermont Yankee Nuclear Power Corporation (Vermont Yankee Nuclear Power Station), LBP-87-7, 25 NRC 116 (1987) ............. 5 Statutes Atomic Energy Act 42 U.S.C. § 2133(c) ............................................................ 8 42 U.S.C. § 2133(d) ........................................................ 6, 50 42 U.S.C. 2239(a)(1) .................................................. 1, 4, 16, 45 NEPA, 42 U.S.C. § 4332 ............................................................ passim Nuclear Waste Policy Act 42 U.S.C. § 10152 ................................................................. 47 Regulations 10 C.F.R. § 2.309 ..................................................................... 1, 5, 17 10 C.F.R. § 2.315 .................................... ..................... ............ 5 10 C.F.R. § 2.335 ........................................................................ 17 10 C.F.R. § 2.744(e) ........................................................................ 45 10 C.F.R. Part 2, Subpart I ................................................................ 45 10 C.F.R. § 50.34(a)(4) ................................................................. 6 10 C.F.R. § 50.109 ............................................................... 2, 9, 49 10 C.F.R. § 51.45(c) ..................................................................... 15 vii

10 C.F.R. § 51.53(c)(2) ................................................................. 12 10 C.F.R. § 5153(c)(3)(i) ............................................................. 12, 13 10 C.F.R. § 5153(c)(3)(iii) ............................................................ 15,22 10 C.F.R. § 5153(c)(3)(iv) ................................................... 15, 21, 23, 33 10 C.F.R. § 51.53(c)(4) ................................................................. 15 10 C .F.R. § 51.71 .................................................................. 11-13,38 10 C .F.R . § 51.71(d) ................................................................... 5, 16 10 C .F.R. § 51.91 ...................................................................... 11, 15 10 C.F.R. § 51.95 ...................................................................... 13 10 C.F.R. Part 51, Table B-1 of Appendix B to Subpart A ............. 12,13, 14,29 40 C.F.R. § 1500.1 ...................................................................... 9 40 C.F.R. § 1502.22(b)(1) ............................................................ 10, 37 Federal Register Notices 36 Fed. Reg. 22,851 ................................................................................. 11 Entergy Nuclear Operations, Inc., Vermont Yankee Nuclear Power Station; Notice of Acceptance for Docketing of the Application and Notice of Opportunity for Hearing Regarding Renewal of Facility Operating License No. DPR-35 for an Additional 20-Year Period, 71 Fed. Reg. 15,222 (March 27, 2006) ........................................................ 1 Final Rule, Environmental Review for Renewal of Nuclear Power Plant Operating Licenses, 61 Fed. Reg. 28,467 (June 5, 1996) .................................. 16 Final Rule, Environmental Review for Renewal of Nuclear Power Plant Operating Licenses, 61 Fed. Reg. 66,537, 66,538, (December 18, 1996) .................. 29 Final Rule, Nuclear Power Plant License Renewal, 56 Fed. Reg. 64,943 (December 13, 1991) ........................... 8, 9, 48 Final Rule, Protection Against Malevolent Use of Vehicles at Nuclear Power Plants, 59 Fed. Reg. 38,889 (August 1, 1994) ................... 34, 35, 38-40 viii

Policy Statement on Severe Accidents Regarding Future Designs and Existing Plants, 50 Fed. Reg. 32,138 (August 8, 1985) .................................. 7-8 Proposed Rule, Nuclear Power Plant License Renewal, 55 Fed. Reg. 29,043 (July 17, 1990) .......................................................... 17 Review and Final Revision of Waste Confidence Decision, 55 Fed. Reg. 38,474 (September 18, 1990) ............................................. 21, 28, 30 Statement of Interim Policy, Nuclear Power Plant Accident Considerations Under the National Environmental Policy Act of 1969, 45 Fed. Reg. 40,101 (1980) .............. 11 NRC Documents Final Environmental Statement Related to Operation of Vermont Yankee Nuclear Power Station, Boston Edison Company, Docket No. 50-293 (May 1972) ............. 21-22 NRC Regulatory Issue Summary 2002-12A, Power Reactors, NRC Threat Advisory and Protective Measures System (August 19, 2002) ................ 35 NUREG-0575, Handling and Storage of Spent Light Water Power Reactor Fuel (1979) ......................................................................... 14, 21, 26, 27,28 NUREG-1 150, Severe Accident Risks for Five U.S. Nuclear Pow er Plants (1990) ............................................................................ 13,49 NUREG-1353, Regulatory Analysis for the Resolution of Generic Issue 82, "Beyond Design-basis Accidents in Spent Fuel Pools" (April 1989)25, 26, 28 NUREG-1437, Generic Environmental Impact Statement for License Renewal of Nuclear Plants (1996)passim NUREG-1555, Environmental Standard Review Plan for Environmental Review for Nuclear Power Plants (October 1999) ........................................................ 42 NUREG- 1738, FinalTechnicalStudy of Spent Fuel PoolAccident Risk and DecommissioningNuclear PowerPlants (January 2001) ........................... 21, 24, 30 NUREG/CR-0649, Spent Fuel Heatup FollowingLoss of Water During Storage (M arch 1979)................................................................. 21, 26, 27, 28 NUREG/CR-4982, Severe Accidents in Spent Fuel Pools in Support of GenericIssue 82 (1987) ....................... I................................................. 28 NUREG/CR-5176, Seismic Failureand Cask DropAnalysis of the Spent Fuel Pools at Two Representative NuclearPower Plants (1989) ................. 28 ix

NUREG/CR-528 1, Value/Impact Analysis ofAccident Preventative and Mitigative Optionsfor Spent FuelPools (1989) ........................................... 28 Remarks by NRC Chairman Nils J. Diaz to the Joint NRC/DHS State Security Outreach Workshop (June 17, 2003) ............................................... 35 SECY-01-0100, Memorandum to the Commissioners from William D. Travers, Executive Director for Operations ("EDO") re: Policy Issues Related to Safeguards, Insurance, and Emergency Preparedness Regulations at Decommissioning Nuclear Power Plants Storing Spent Fuel in Spent Fuel Pools (WITS 200000126) (June 4, 2001) ...................................... 36 WASH-1400, Reactor Safety Study (1975) ................................................. 25 Miscellaneous William Branigan, In Afghan Jail,a Terrorist Who Won't Surrender, Washington Post, October 30, 2001 .............................................................. 35 DOE/EIS-0250F, Final Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada (February 2002) ............................................. 46 DOE/EIS-236-S2, Draft Supplemental Programmatic Environmental Impact Statement on Stockpile Stewardship and Management for a Modern Pit Facility, Vol. II (M ay 2003) .............................................................................. 46 DOE/EIS-0161, Final Programmatic Environmental Impact Statement for Tritium Supply and Recycling, Vol. I (October 1995) ................................................... 46 DOE/EIS-0319, Final Environmental Impact Statement for the Proposed Relocation of Technical Area 18 Capabilities and Materials at the Los Alamos National Laboratory (August 2002) ...................................................................... 46 Robert S. Mueller, Testimony before the Senate Committee on Intelligence of the United States Senate (February 16, 2005) .......................... 35 NAS Committee on the Safety and Security of Commercial Spent Nuclear Fuel Storage, Safety and Security of CommercialSpent Nuclear Fuel Storage (The National Academies Press: 2006) ...................... 22, 24, 30, 31, 37 National Strategy for the Physical Protection of Critical Infrastructures and Key Assets (February 2003) ............................................................. 35 NRC Regulatory Issue Summary 2002-12A, Power Reactors, NRC Threat Advisory and Protective Measures System (August 19, 2002) ............ 35 x

I. INTRODUCTION AND EXECUTIVE

SUMMARY

On behalf of the Commonwealth of Massachusetts, Attorney General Thomas F.

Reilly ("Massachusetts Attorney General" or "Petitioner") petitions to intervene and requests the U.S. Nuclear Regulatory Commission ("NRC" or "Commission") to grant an adjudicatory hearing on Entergy Nuclear Operations, Inc.'s ("Entergy's") application for renewal of its license to operate the Vermont Yankee nuclear power plant. He files this petition pursuant to the notice of opportunity for a hearing published at 71 Fed. Reg.

15,222 (March 27, 2006), Section 189a of the Atomic Energy Act ("AEA") [42 U.S.C. § 2239(a)], and 10 C.F.R. § 2.309.

Through its application, Entergy seeks approval to operate the Vermont Yankee plant an additional 20 years past its expiration date of 2012. As a general matter the Attorney General does not oppose Entergy's renewal application, and he acknowledges that nuclear power provides an important component of the New England energy supply.

At the same time, however, he wants to ensure that the NRC does not grant the license renewal before Entergy and the NRC address the risk of a severe accident in the Vermont Yankee spent fuel pool and comply with federal laws for the protection of public health, safety, and the environment.

As detailed below in the Petitioner's contention (see Section V below), Entergy's license renewal application fails to comply with the National Environmental Policy Act's

("NEPA's") requirement that it address significant new information bearing on the environmental impacts of operating the Vermont Yankee nuclear power plant during a license renewal term. That new information, not addressed in any previous Environmental Impact Statement ("EIS") for the Vermont Yankee nuclear plant or any I

other nuclear power plant, demonstrates that continued storage of spent fuel in high-density storage racks in the Vermont Yankee pool poses a significant and reasonably foreseeable environmental risk of a severe fire and offsite release of a large amount of radioactivity. Entergy's failure to take account of this new information is inconsistent with NEPA's major requirement that environmental decisions must take new information into account if the information shows that a proposed action will affect the quality of the human environment "in a significant manner or to a significant extent not already considered." Marsh v. Oregon NaturalResources Council,490 U.S. 360, 374 (1989)

("Marsh").

Entergy's application also fails to satisfy the AEA's fundamental requirement to ensure safe operation of the Vermont Yankee plant during the license renewal term because it does not include adequate design measures to prevent the occurrence of a pool fire or to reduce its consequences. Therefore, pursuant to 10 C.F.R. § 50.109(a)(5), the Attorney General petitions the Commission to require that Entergy backfit the Vermont Yankee design to eliminate or substantially mitigate the risk of a pool fire. The choice of design measure for the backfit should be informed by the consideration of backfit design alternatives in an EIS.

The Attorney General's hearing request and backfit petition arise from the safety and environmental risks posed by Entergy's plan to continue to use "high-density" racks for storage of spent fuel in the Vermont Yankee fuel pool. When the Vermont Yankee plant was originally licensed in 1972, "low-density" racks were used to store spent fuel in the pool. The open construction of these racks allowed cooling fluid to flow freely all around and over the spent fuel assemblies stored in the pool. Under several license 2

amendments granted between 1972 and 1994, the NRC has allowed Entergy to pack fuel more and more densely into the pool, using "high-density" storage racks. By the time the current license term expires in 2012, Entergy will have accumulated some three thousand fuel assemblies in the Vermont Yankee fuel pool, amounting to approximately forty million curies of radioactive isotopes. If the fuel pool were to suffer a loss of water sufficient to uncover the tops of the fuel assemblies, the dense configuration of the high-density racks would inhibit the flow of water, air or steam over the fuel assemblies, causing some of the fuel to ignite within hours. The fire could then propagate within the pool, and the burning of fuel assemblies could lead to a large atmospheric release of radioactive isotopes, contaminating a large land area for decades and at a heavy cost to public health and the economy.

While such a catastrophic accident is unlikely, its probability falls within the range that NRC considers reasonably foreseeable. Therefore it is not a speculative or worst-case event. Pool water could also be lost if the pool were the subject of an intentional attack, a risk that can no longer be ignored after the attacks of September 11, 2001. Yet, neither Entergy nor the NRC has addressed the safety and environmental impacts of a pool fire in any EIS, nor is the Vermont Yankee plant designed to avoid a pool fire accident.

Although it has long been known that high-density pool storage of spent fuel could potentially lead to a serious accident, the scientific information on such risks has continued to develop in recent years, including through technical studies by the Commission's own staff, independent expert analyses, and a study by the National Academies of Sciences. Increased appreciation for the potential for an intentional attack 3

if" on nuclear facilities has also changed our consideration of that risk. Despite the NRC's acknowledgment of concern about such a risk, and despite the known vulnerability of fuel pools to fire if they are intentionally drained, the agency has not addressed the potential safety and environmental impacts of attacks involving fuel pools. Marsh and NRC regulations require that prior to licensing Vermont Yankee, the NRC must prepare an EIS that addresses significant new information regarding the safety and environmental impacts of a pool fire. This information was not available to the NRC when earlier EISs relevant to license renewal were prepared. Under NEPA, the EIS must also weigh reasonably available alternatives for avoiding or mitigating a pool fire, such as combined low-density pool storage and dry storage of spent fuel.

The AEA also requires the NRC to protect against the unreasonable risk of a pool fire in its license renewal decision for Vermont Yankee. Petitionfor Emergency and RemedialAction, CLI-78-6, 7 NRC 400, 404 (1978) ("Petitionfor Emergency and RemedialAction"). Therefore, the NRC must not only assess the impacts of pool fires in an EIS, it must require Entergy to change the design or operations of the plant to prevent a pool fire from occurring.

II. THE MASSACHUSETTS ATTORNEY GENERAL HAS STANDING TO INTERVENE IN THIS PROCEEDING AND REQUEST A BACKFIT ORDER.

Section 189a of the AEA, 42 U.S.C. § 2239(a)(1), provides that:

In any proceeding under this Act, for the granting, suspending, revoking, or amending of any license.., the Commission shall grant a hearing upon the request of any person whose interest may be affected by the proceeding, and shall admit any person as a party to such a proceeding.

As previously established, the Attorney General has standing to intervene in a proceeding involving the safety of pool storage of spent fuel at Vermont Yankee.

4

Vermont Yankee Nuclear Power Corporation(Vermont Yankee Nuclear Power Station),

LBP-87-7, 25 NRC 116, 118 (1987) ("Vermont Yankee").'

The Attorney General is concerned that Entergy and the NRC have not adequately informed the public regarding the risks of a severe accident in the Vermont Yankee spent fuel pool during the license renewal term, nor have they implemented adequate design measures to avoid such an accident. Therefore, the Attorney General seeks enforcement of federal laws requiring the preparation of an EIS regarding the risks of storing spent fuel in the Vermont Yankee pool, as well as the imposition of design measures for avoiding those accidents. If granted, this relief would improve the level of protection of 2

the environment and public health and safety of the residents of Massachusetts.

III. STATUTORY AND REGULATORY FRAMEWORK The two statutes that govern this hearing request and backfit petition are NEPA and the AEA. The AEA sets minimum standards for safe and secure operation of nuclear facilities, while NEPA requires NRC to consider and attempt to avoid or mitigate significant adverse environmental impacts of licensing those facilities. Although the statutes have some overlapping concerns, they establish independent requirements.

Limerick Ecology Action v. NRC, 869 F.2d 719, 729-30 (3 rd Cir. 1989). NEPA goes I The Attorney General satisfies the requirements of 10 C.F.R. § 2.309(d) for demonstrating standing. The Attorney General has an interest in this proceeding because the Vermont Yankee nuclear power plant lies within ten miles of the Commonwealth of Massachusetts. An accidental offsite release of radioactivity from the Vermont Yankee fuel pool during the proposed license renewal term could affect the health and well-being of Massachusetts residents, the integrity of the environment, and the economic welfare of the Commonwealth.

2 As an elected representative of the citizens of the Commonwealth of Massachusetts, the Attorney General also has the right to participate in this proceeding as a representative of an interested State. 10 C.F.R. § 2.315(c). See also Vermont Yankee, 25 NRC at 118.

5

It beyond the AEA, requiring the consideration of alternatives to reduce or avoid adverse environmental impacts of NRC licensing actions. Id., citing 10 C.F.R. § 51.71 (d).3 A. Atomic Energy Act Safety Requirements

1. AEA requirements for protection of public safety The AEA prohibits the NRC from issuing a license to operate a nuclear power plant if it would be "inimical to the common defense and security or to the health and safety of the public." 42 U.S.C. § 2133(d). Public safety is "the first, last, and a permanent consideration in any decision on the issuance of a construction permit or a license to operate a nuclear facility." Petitionfor Emergency and Remedial.Action, 7 NRC at 404, citing Power Reactor Development Corp. v. InternationalUnion of ElectricalRadio and Machine Workers, 367 U.S. 396, 402 (1961) ("PowerReactor Development Corp.").

2. NRC requirements for protection against design-basis accidents NRC regulations for implementation of the AEA provide that a nuclear power plant must be designed against accidents that are "anticipated during the life of the facility." See 10 C.F.R. § 50.34(a)(4), which provides that a construction permit application for a nuclear power plant must include:

a preliminary analysis and evaluation of the design and performance of structures, systems, and components of the facility with the objective of assessing the risk to public health and safety resulting from operation of the facility and including determination of the margins of safety during normal operations and transient conditions anticipated during the life of the facility, and the adequacy of 3 As the Court observed in Limerick, it is "unreasonable to suppose that

[environmental] risks are automatically acceptable, and may be imposed upon the public by virtue of the AEA, merely because operation of a facility will conform to the Commission's basic health and safety standards." Id. quoting Citizensfor Safe Power v.

NRC, 524 F.2d 1291, 1299 (D.C. Cir. 1975).

6

structures, systems, and components provided for the prevention of accidents and the mitigation of the consequences of accidents.

These "anticipated" accidents, against which nuclear power plants must be designed, are called "design-basis accidents." See NUREG-1437, Generic Environmental Impact Statement for License Renewal of Nuclear Plants at 5-1 (1996) ("License Renewal GELS"). Design-basis accidents include low-frequency but credible events. Id. at 5-2.

In determining which types of accidents constitute design-basis accidents and therefore must be protected against in a nuclear plant's design, the NRC sets a "threshold" based on probability of the accident. The NRC has held that reactor core accidents with a "realistic probability" (i.e., a non-conservative probability) of at least 4

one in ten million per year (10-7) must be included in the design-basis.

The NRC designates accidents that are more complex and less likely than design-basis accidents as "severe accidents." License Renewal GEIS at 5-1 (severe accidents are "those involving multiple failures of equipment or function and, therefore, whose likelihood is generally lower than design-basis accidents but whose consequences may be higher"). Although severe accidents are "beyond the substantial coverage of design-basis events," they constitute "the major risk to the public associated with radioactive releases from nuclear power plant accidents." Policy Statement on Severe Accidents Regarding 4 PrivateFuel Storage, L.L.C. (Independent Spent Fuel Storage Installation),

CLI-01-22, 54 NRC 255, 259-60 (2001) ("PFSI"), citing MetropolitanEdison Co.

(Three Mile Island Nuclear Station, Unit 2), ALAB-692, 16 NRC 921 (1982); Consumers Power Co. (Big Rock Point Plant), LBP-84-32, 20 NRC 601, 639-52 (1984).

But see Vermont Yankee Nuclear Power Corp. (Vermont Yankee Nuclear Power Station),

CLI-90-4, 31 NRC 333, 334 (1990), in which the Commission refused to rule out NEPA consideration of an accident probability of 10 4 per year as remote and speculative.

Under the PFSIruling, an accident with a probability of 10.4 would be well within the range of a design-basis accident. Therefore, not only should it have been considered credible for purposes of preparing an EIS, but it should have been included in the design-basis for the facility.

7

Future Designs and Existing Plants, 50 Fed. Reg. 32,138, 32,139 (August 8, 1985)

("Severe Accident Policy Statement").

The Commission has made a generic determination that nuclear plants can be operated safely, despite the potential for severe accidents. Severe Accident Policy Statement, 50 Fed. Reg. at 32,13940. See also Final Rule, Nuclear Power Plant License Renewal, 56 Fed. Reg. 64,943, 64,948-49 (December 13, 1991). Nevertheless, the Commission has an ongoing program to address severe accidents in the context of its regulatory program for protection of public health and safety under the Atomic Energy Act, and pledges to act upon any new information that calls the safety finding into question. Id. As provided by the Severe Accident Policy Statement:

Should significant new safety information become available, from whatever source, to question the conclusion of 'no undue risk,' then the technical issues thus identified would be resolved by the NRC under its backfit policy and other existing procedures, including the possibility of generic rulemaking where this is justified.

50 Fed. Reg. at 32,139.

3. Standard for license renewal Section 2133(c) of the Atomic Energy Act allows the NRC to renew nuclear power licenses. Although the AEA does not set a safety standard for license renewal, the Commission generally interprets the AEA to require that it "must have 'reasonable assurance' that public health and safety are not endangered by its licensing actions."

Petitionfor Emergency and Remedial Action, 7 NRC at 404, citing Power Reactor Development Corp., 367 U.S. at 402.

In the license renewal rulemaking, the Commission made a determination that:

With the exception of age-related degradation unique to license renewal and possibly some few other issues related to safety only during extended operation, 8

the regulatory process is adequate to ensure that the licensing bases of all currently operating plants provide and maintain an acceptable level of safety for operation so that operation will not be inimical to public health and safety or common defense and security.

56 Fed. Reg. at 64,946. Thus, other than with respect to aging issues, the NRC does not inquire into safety issues in the license renewal process.

If significant new information becomes available with respect to a safety issue unrelated to the aging of the plant, the NRC does not permit it to be raised in the license renewal hearing. Preamble to Final License Renewal Rule, 56 Fed. Reg. at 64,946.

Instead, the NRC requires that the issue must be addressed under the NRC policy for backfitting the design of operating reactors in 10 C.F.R. § 50.109, or under "other existing procedures, including the possibility of generic rulemaking." Id.5 B. NEPA Statutory and Regulatory Requirements

1. General NEPA requirements

a. NEPA requirement to prepare an EIS NEPA is the "basic charter for protection of the environment." 40 C.F.R. § 1500.1. Its fundamental purpose is to "help public officials make decisions that are based on understanding of environmental consequences, and take decisions that protect, restore and enhance the environment." ld. NEPA requires federal agencies to examine the environmental consequences of their actions before taking those actions, in order to ensure "that important effects will not be overlooked or underestimated only to be discovered after resources have been committed or the die otherwise cast." Robertson v.

Methow Valley Citizens Council (Robertson), 490 U.S. 332, 349 (1989).

5 Among these options the Massachusetts Attorney General has elected to request a backfit to design the Vermont Yankee plant against pool fires. See Section VI. below.

9

The primary method by which NEPA ensures that its mandate is met is the "action-forcing" requirement for preparation of an EIS, which assesses the environmental impacts of the proposed action and weighs the costs and benefits of alternative actions.

Id., 490 U.S. at 350-51. An EIS must be rigorous, providing a "hard look" at the environmental consequences of the proposed action. Id. at 349; Marsh, 490 U.S. at 374.

b. NEPA requirement to supplement an EIS The completion of an EIS for a proposed action does not end an agency's responsibility to weigh the environmental impacts of a proposed action. Marsh, 490 U.S.

at 371-72. As the Supreme Court recognized in Marsh, it would be incongruous with NEPA's "action-forcing" purpose to allow an agency to put on "blinders to adverse environmental effects," just because the EIS has been completed. Id. Accordingly, up until the point when the agency is ready to take the proposed action, it must supplement the EIS if there is new information showing that the remaining federal action will affect the quality of the human environment "in a significant manner or to a significant extent not already considered." 490 U.S. at 374.

C. NEPA requirement that an EIS must consider reasonably foreseeable impacts of nuclear accidents.

The environmental impacts that must be considered in an EIS include "reasonably foreseeable" impacts which have "catastrophic consequences, even if their probability of occurrence is low." 40 C.F.R. § 1502.22(b)(1). The Commission has held that probability is the "key" to determine whether an accident is "reasonably foreseeable" or 6

whether it is "remote and speculative" and therefore need not be considered in an EIS.

6 Vermont Yankee Nuclear Power Corp. (Vermont Yankee Nuclear Power Station), CLI-90-7, 32 NRC 129, 131 (1990). See also Limerick Ecology Action v. NRC, 10

In the spectrum of accidents that might be considered in an EIS for a nuclear power plant license, there is no dispute that "design-basis accidents," i.e., accidents against which a nuclear plant must be designed under the AEA's requirement to protect public health and safety against "undue risk," are reasonably foreseeable and therefore must be considered.

Thus, almost since the passage of NEPA the NRC has included consideration of the environmental impacts of design-basis accidents in its EISs. Limerick Ecology Action v.

NRC, 869 F.2d 719, 726 (3rd Cir. 1989), citing 36 Fed. Reg. 22,851 (1971).

In 1980, following the Three Mile Island accident, the Commission also began to consider the environmental impacts of severe or "beyond design-basis" accidents in its EISs. Id., citing Statement of Interim Policy, Nuclear Power Plant Accident Considerations Under the National Environmental Policy Act of 1969, 45 Fed. Reg.

40,101 (1980). In contested cases the Commission has required intervenors to address the quantitative probability of severe accidents for which they seek consideration in an EIS. See, e.g., CarolinaPower & Light Co. (Shearon Harris Nuclear Power Plant), CLI-01-11, 53 NRC 370, 387 (2001) ("Harris"). While the Commission has not established a threshold for the level of accident probability considered "reasonably foreseeable," in Harristhe Commission affirmed a decision by the ASLB approving the NRC Staff's probability estimate of 10"7 for a particular accident scenario and ruling that the accident was "remote and speculative." Id. at 388 n.8. (But see Section III.A.2 above.)

2. NRC's procedures for preparation of ER and EIS NRC's NEPA procedures require the NRC to prepare an EIS for any major licensing action significantly affecting the quality of the human environment. 10 C.F.R.

869 F.2d at 745, citing Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, Inc., 435 U.S. 519, 551 (1978).

I1

§§ 51.71, 51.91. Before the EIS is prepared, however, the NRC's regulations require that the license applicant must prepare what amounts to a first draft of the EIS, i.e., the environmental report ("ER"). 10 C.F.R. § 51.53(c)(2), Duke Power Co. (Catawba Nuclear Station, Units I and 2), CLI-83-19, 17 NRC 1041, 1049 (1983) (noting that "as a practical matter, much of the information in an Applicant's ER is used in the [Draft EIS]"). The ER generally must address all the same impacts, alternatives, and other environmental issues that will be addressed later in the NRC's EIS. Compare 10 C.F.R.

§ 51.53(c)(2) with 10 C.F.R. § 51.71.

3. NRC's NEPA procedures for license renewal

a. NRC reliance on License Renewal GEIS in individual license renewal proceedings NRC regulations for the implementation of NEPA do not require the preparation of a complete ER and EIS for every nuclear power plant license renewal application.

Instead, the NRC relies on the License Renewal GEIS, prepared in 1996, to evaluate most of the environmental impacts of license renewal. See 10 C.F.R. §§ 51.53(c)(3)(i),

51.71(d).

The License Renewal GEIS and NRC's environmental regulations for license renewal-related NEPA issues separate environmental impacts, including accidents, into two major categories: Category I or "generic" impacts, and Category 2 or "plant-specific" impacts. Duke Energy Corporation(McGuire Nuclear Station, Units 1 and 2; Catawba Nuclear Station, Units I and 2), CLI-02-14, 55 NRC 278, 290 (2002)

("McGuire/Catawba"). Environmental impacts are listed according to their category in Table B-i of Appendix B to Subpart A of 10 C.F.R. Part 51.

For Category I impacts, the NRC considers the License Renewal GEIS analysis 12

sufficient, and no further analysis is required in the Environmental Report and EIS that are prepared at the time of the license renewal application. 10 C.F.R. §§ 51.53(c)(3)(i),

51.71, 51.95(c). For Category 2 impacts, the NRC has determined that impacts and alternatives cannot be fully addressed in the Generic EIS and therefore must be addressed in the site-specific ER and EIS. McGuire/Catawba,55 NRC at 290; FloridaPower &

Light Co. (Turkey Point Nuclear Generating Plant, Units 3 and 4), CLI-0 1-17, 54 NRC 3, 12 (2001).

b. NRC discussion of accident'impacts in License Renewal GEIS The License Renewal GEIS purports to address both design-basis accidents and severe accidents. With respect to design-basis accidents, the GEIS provides a brief statement that the impacts of design-basis accidents were considered in the original EIS for each nuclear power plant, and that the design was found adequate to "accommodate" those accidents. License Renewal GElS at 5-11. Moreover, the GEIS asserts that the consequences of design-basis accidents are not expected to change significantly as a result of aging of the plant. Id. Therefore, the GEIS does not provide a further discussion of design-basis accidents. Id. These impacts are also classified as "Category I in Table B-1 of Appendix B to Subpart A of 10 C.F.R. Part 51.

With respect to severe or beyond design-basis accidents, the License Renewal GEIS discusses the potential consequences of an array of severe accidents identified in various studies, primarily the NRC's most recent and comprehensive probabilistic analysis of nuclear power plant accidents, NUREG-1 150, Severe Accident Risks for Five U.S. Nuclear Power Plants (1990). While recognizing the possibility that the likelihood of some severe accidents may be so low as to be "remote and speculative" and therefore 13

not necessary to discuss in an EIS, the License Renewal GElS does not exclude any severe accidents on the ground of their estimated probability. Severe accidents are classified as "Category 2" impacts in Table B-1 of Appendix B to Subpart A of 10 C.F.R.

Part 51.

The License Renewal GElS does not include any discussion of how deliberate and malicious attacks on nuclear power plants may increase the likelihood or consequences of severe accidents. The NRC declines to address the topic on the grounds that (a) NRC security regulations provide reasonable assurance that the risk from sabotage is small; (b) although their probability is not quantifiable, acts of sabotage are "not reasonably expected"; and (c) even if such an event were to occur, resultant core damage and radiological releases would be "no worse than those expected from internally initiated events." License Renewal GEIS at 5-18.7 The License Renewal GETS is consistent with the NRC's long-established policy of refusing to examine the environmental impacts of deliberate malicious acts on the ground that it could not make a "meaningful assessment of the risks of sabotage."

PhiladelphiaElectric Co. (Limerick Generating Station, Units I and 2), ALAB-819, 22 NRC 681, 697-701 (1985) ("Limerick Appeal BoardDecision'), aff'd on this ground and rev'd on other grounds, Limerick EcologyAction v. NRC, 869 F.2d 719, 743-44 (3rd Cir.

1989). Even the attacks of September 11, 2001, did not cause the NRC to change this policy, which it reiterated in PrivateFuel Storage,L.L.C. (Independent Spent Fuel 7 The NRC's failure to discuss impacts of deliberate and malicious acts in the License Renewal GETS is a departure from the 1979 GELS, in which the NRC examined the impacts of attacks on spent fuel pools, albeit not in light of significant new information about the risks of pool fires, NUREG-0575, Handling and Storage of Spent Light Water Power Reactor Fuel (1979) ("1979 GELS"). See discussion in Section V.B.1.c, below.

14

Storage Installation, CLI-02-25, 56 NRC 340 (2002) ("PFSI1") and Pacific Gas &

Electric Company (Diablo Canyon ISFSI), CLI-03-12, 58 NRC 185 (2003) ("Diablo Canyon ,).8 Diablo Canyon has been appealed to the U.S. Court of Appeals for the 9th Circuit, where a decision is pending. Moreover, to the extent that PFS H and Diablo Canyon are based on factual determinations that should be re-evaluated in a new EIS in light of significant new information, the policy is subject to challenge in this proceeding.

10 C.F.R. § 51.53(c)(3)(iv). See discussion below in Section III.B.3.c.

c. NRC requirement to supplement License Renewal GEIS Consistent with Marsh, 490 U.S. at 374, NRC regulation 10 C.F.R. § 51.53(c)(3)(iv) requires that an environmental report "must contain any new and significant information regarding the environmental impacts of license renewal of which the applicant is aware." Thus, the conclusions of the License Renewal GElS are subject to modification in individual license renewal proceedings if new and significant information, not evaluated in the License Renewal GEIS, shows that the environmental impacts of license renewal are greater than concluded in the License Renewal GEIS.

d. NRC requirement to consider alternatives in site-specific ER and EIS For any environmental impacts that do not fall into Category 1, a license renewal applicant must consider "alternatives for reducing adverse impacts," including severe accidents. 10 C.F.R. § 51.53(c)(3)(iii), citing 10 C.F.R. § 51.45(c). This requirement 8 For other decisions applying the NRC's policy against considering the environmental impacts of terrorism and sabotage, see Duke Cogema Stone & Webster (Savannah River Mixed Oxide Fuel Fabrication Facility), CLI-02-24, 56 NRC 335 (2002); Dominion Nuclear Connecticut, Inc. (Millstone Nuclear Power Station, Unit 1),

CLI-02-27, 56 NRC 367 (2002); Duke Energy Corp. (McGuire Nuclear Station, Units I and 2), Catawba Nuclear Station, Units I and 2), CLI-02-26, 56 NRC 358 (2002).

15

also applies to the draft and final EIS for each individual license renewal application. 10 C.F.R. § 51.71(d), 51.91.

As the Commission explained in the preamble to the final rule for environmental review of license renewal applications, the alternatives that must be considered include severe accident mitigation alternatives ("SAMAs"). Final Rule, Environmental Review for Renewal of Nuclear Power Plant Operating Licenses, 61 Fed. Reg. 28,467, 28,480-81 (June 5, 1996). This requirement is:

based on the Commission's NEPA regulations that require a review of severe

[accident] mitigation alternatives in its environmental impact statements (EISs) and supplements to EISs, as well as a previous court decision that required review of severe mitigation alternatives (referred to as SAMDAs) at the operating license stage. See, Limerick Ecology Action v. NRC, 869 F.2d 719 (3d Cir. 1989).

61 Fed. Reg. at 28,481. In addition, the Commission noted that while each licensee was in the process of performing an individual plant examination ("IPE") to "look for plant vulnerabilities to internally initiated events" and a separate IPE "for externally initiated events (IPEEE)," the program had not been completed in time to include the results in an EIS or supplemental EIS. Id. Thus, the ER and EIS for each individual license renewal application must include consideration of SAMAs. Id.

C. Atomic Energy Act Public Hearing Requirements for License Renewal Decisions.

Section 189a of the AEA requires the NRC to provide interested members of the public with a prior opportunity for a hearing on any decision regarding the issuance or amendment of a nuclear facility license. 42 U.S.C. § 2239(a)(1)(A). While the AEA does not establish a specific right to a hearing for license renewal proceedings, the Commission has determined that a hearing should be granted because renewal of an 16

operating license "is essentially the granting of a license." Proposed Rule, Nuclear Power Plant License Renewal, 55 Fed. Reg. 29,043, 29,052 (July 17, 1990).

In order to be admitted as an intervenor to an NRC adjudicatory licensing proceeding, including a license renewal proceeding, a petitioner must file "contentions" that provide "sufficient information to show that a genuine dispute exists with the applicant/licensee on a material issue of law or fact." 10 C.F.R. § 2.309(f)(vi).

Contentions raising questions of compliance with NRC safety requirements must be based on the application, and contentions raising questions of compliance with NEPA must be based on the applicant's ER. 10 C.F.R. § 2.309(f.

Pursuant to 10 C.F.R. § 2.335, contentions may not challenge NRC regulations.

However, factual determinations codified in NRC NEPA regulations may be challenged under regulations and judicial precedents requiring the consideration of significant new information that undermines those determinations. See discussion above in Sections III.B. L.b and III.B.3.c. In addition, contentions may challenge fact-based statements of NRC policy that were established without notice or opportunity for public comment.

Limerick Ecology Action v. NRC, 869 F.2d at 733-39.9 9 In the Limerick proceeding, which took place in the 1980s, the Intervenor submitted a contention challenging the NRC's pronouncement in an EIS that it would not consider the environmental impacts of sabotage against a proposed nuclear plant because it lacked any meaningful method of assessing the likelihood of sabotage events at a proposed nuclear power plant. 849 F.2d at 743. The Court upheld the NRC's holding that the Intervenor "failed to produce any credible evidence or theory that would 'cast any serious doubt' on the Commission's conclusion that sabotage risk analysis is beyond current probabilistic risk assessment methods and that there is no current basis by which to measure such risk." Id. Thus, the court recognized the Intervenor's right to challenge the NRC's policy pronouncement regarding consideration of intentional attacks on a nuclear facility in the specific licensing proceeding in which it had intervened. While the Third Circuit upheld the Commission's ruling that the Limerick Intervenor failed to present enough evidence to challenge the factual basis for the policy, that is not the case here. In its contention below, the Attorney General presents a significant body of evidence 17

IV. FACTUAL AND PROCEDURAL BACKGROUND A. Vermont Yankee Nuclear Power Plant

1. Pool Storage of Spent Fuel at Vermont Yankee At the Vermont Yankee nuclear power plant, electricity is generated by fission reactions in radioactive "fuel rods" in the plant's reactor. Fuel rods are grouped together in "assemblies." After a fuel assembly is "spent" in the sense that it no longer can be used to generate power, it is discharged from the reactor. However, at this point in its life the assembly is much more dangerous than when it entered the reactor. It emits heat and intense radiation, and contains a large inventory of radioactive material. Gordon Thompson, Risks and Risk-Reducing Options Associated with Pool Storage of Spent Nuclear Fuel at the Pilgrim and Vermont Yankee Nuclear Power Plants, § 2 (May 25, 2006) ("Thompson Report").' 0 The Vermont Yankee plant has a fuel storage pool through which fresh fuel assemblies pass during their placement in the reactor, and where spent fuel is stored after it is removed from the reactor core. When Vermont Yankee and other plants in the present generation of nuclear power plants first began operation in the 1970s, their spent fuel pools were equipped with low-density, open-frame racks. These racks allowed free circulation of water around the fuel assemblies. If water were lost from a pool equipped with open-frame racks, air or steam could circulate freely through the fuel assemblies, cooling the assemblies. As a result, the fuel cladding would ignite, if at all, only in rare conditions. Thompson Report, § 8.

showing that the NRC's policy is unfounded.

10 A copy of Dr. Thompson's report is attached to the Declaration of Dr.

Gordon Thompson in Support of Massachusetts Attorney General's Contention and Petition for Backfit Order (May 25, 2006, which is included as Exhibit I to this pleading.

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Over the past three decades, spent fuel inventories have mounted because of the lack of other means of spent fuel management. Plant licensees have responded to this problem by substantially increasing the density at which fuel is stored in the existing spent fuel pools. In order to increase the density of storage, licensees have been obliged to use racks in which each fuel assembly is surrounded by solid, neutron-absorbing panels, which are needed to suppress criticality or a runaway chain reaction. The panels limit the flow of coolant (water, air or steam) to a mode of circulation in which the coolant enters each rack cell from below, rises vertically through the cell, and leaves the cell at its top.

The Vermont Yankee license has been amended several times to permit storage of an ever-increasing volume of spent fuel in high-density storage racks. Currently, all racks in the Vermont Yankee pool are high-density. During the requested period of license extension, the Vermont Yankee fuel pool will contain about 2,600 fuel assemblies with a radioactive inventory of about 39 million curies of cesium-137. Thompson Report, Table 3-4.

If water is lost from a pool equipped with high-density racks, the circulation of coolant over the fuel assemblies will be inhibited, and the fuel will ignite over a wide range of conditions. Thompson Report, § 2. See also discussion below in Section V.B.3.

A pool fire at Vermont Yankee could release between 3.9 and 39 million curies of radioactive cesium, contaminating a large land area with radioactive cesium-137 for decades, at a cost of many billions of dollars. Thompson Report, § 5; Jan Beyea, Report to the Massachusetts Attorney General on the Potential Consequences of a Spent-fuel Pool Fire at the Pilgrim or Vermont Yankee Nuclear Plant at 21-24 (May 25, 2006) 19

a.

("Beyea Report")."1

2. Availability of dry storage as an alternative to pool storage Dry storage is an alternative to wet storage that involves placement of the spent fuel in containers (casks or canisters) that are filled with a noncorrosive gas such as helium. Cooling is achieved by convective (i.e., passive) circulation of air over the fuel containers. In comparison with high-density pool storage, dry storage is more expensive because it requires the purchase and installation of new equipment. However, dry storage eliminates the potential for a pool fire and, if properly executed, dramatically reduces the potential for other modes of release of the radioactive material in spent fuel. Thompson Report, § 8. Thus, the expense is well-justified. Id., § 9; Beyea Report, Tables 4 and 5.

To this date, Entergy has not implemented dry storage at the Vermont Yankee nuclear power plant.

B. Vermont Yankee license renewal application Entergy's license for the Vermont Yankee nuclear power plant is due to expire in 2012. On January 25, 2006, Entergy submitted an application to the NRC for renewal of its operating license for an addition 20-year term, or until 2032. Entergy License Renewal Application, Vermont Yankee Nuclear Power Station ("License Renewal Application"). As required by 10 C.F.R. § 51.53(c), the license renewal application included an ER, which purported to address the site-specific environmental impacts of the proposed operation during the renewal term and other related issues. Vermont Yankee License Renewal Application, Appendix E, Applicant's Environmental Report

("Vermont Yankee ER"). The Vermont Yankee ER addresses the environmental impacts 11 A copy of Dr. Beyea's report is attached to the Declaration of Dr. Jan Beyea in Support of Massachusetts Attorney General's Contention and Petition for Backfit Order (DATE), which is included as Exhibit 2 to this pleading.

20

6.

of accidents in Section 4, relying to a significant extent on the License Renewal GEIS for the evaluation of environmental impacts. See ER at 4-1, 4-41. In response to its regulatory obligation to identify "new and significant" information regarding the environmental impacts of license renewal, Entergy also states that it is aware of none.

ER at 5-2, citing 10 C.F.R. § 51.53(c)(3)(iv).

V. CONTENTION: THE ENVIRONMENTAL REPORT FOR RENEWAL OF THE VERMONT YANKEE NUCLEAR POWER PLANT FAILS TO SATISFY NEPA BECAUSE IT DOES NOT ADDRESS THE ENVIRONMENTAL IMPACTS OF SEVERE SPENT FUEL POOL ACCIDENTS.

A. Contention The Vermont Yankee ER does not satisfy the requirements of 10 C.F.R. § 51.53(c)(3)(iv) and NEPA, 42 U.S.C. § 4332 etseq., because it fails to address new and significant information regarding the reasonably foreseeable potential for a severe accident involving nuclear fuel stored in high-density storage racks in the Vermont Yankee fuel pool. Although an NRC-sponsored study conducted as early as 1979 raised the potential for a severe accident in a high-density fuel storage pool if water is partially lost from the pool (NUREG/CR-0649, Spent Fuel Heatup FollowingLoss of Water DuringStorage (March 1979) ("1979 Sandia Report")), the NRC has failed to take that risk into account in every EIS it has prepared, including the 1979 GElS on the environmental impacts of fuel storage; the 1990 Waste Confidence rulemaking (Review and Final Revision of Waste Confidence Decision, 55 Fed. Reg. 38,474, 38,481 (September 18, 1990) ("1990 Waste Confidence Rulemaking"); and the 1996 License Renewal GEIS on which the Vermont Yankee license renewal application relies.

Moreover, the environmental impacts of a pool accident were not considered in the 1972 21

EIS issued in support of the original operating license for the Vermont Yankee nuclear power plant (Final Environmental Statement Related to Operation of Vermont Yankee Nuclear Power Station, Boston Edison Company, Docket No. 50-293 (May 1972) ("1972 Vermont Yankee EIS")).

Significant new information now firmly establishes that (a) if the water level in a fuel storage pool drops to the point where the tops of the fuel assemblies are uncovered, the fuel will bum, (b) the fuel will burn regardless of its age, (c) the fire will propagate to other assemblies in the pool, and (c) the fire may be catastrophic. See Thompson Report and Beyea Report. This new information has also been confirmed by the NRC Staff in NUREG-1738, FinalTechnical Study of Spent Fuel PoolAccident Risk and DecommissioningNuclear Power Plants (January 2001) ("NUREG-l 738"), and by the National Academies of Sciences. See NAS Committee on the Safety and Security of Commercial Spent Nuclear Fuel Storage, Safety and Security of CommercialSpent Nuclear Fuel Storage at 53-54 (The National Academies Press: 2006) ("NAS Report").12 Moreover, significant new information, including the attacks of September 11, 2001 and the NRC's response to those attacks, shows that the environmental impacts of intentional destructive acts against the Vermont Yankee fuel pool are reasonably foreseeable. Taken together, the potential for severe pool accidents caused by intentional malicious acts and by equipment failures and natural disasters such as earthquakes is not only reasonably foreseeable, but is likely enough to qualify as a "design-basis accident,"

i.e., an accident that must be designed against under NRC safety regulations. Thompson Report, §§ 6,7,9.

12 Relevant excerpts of NUREG-1738 and the NAS Report are attached as Exhibits 3 and 4, respectively.

22

The ER also fails to satisfy 10 C.F.R. § 51.53(c)(3)(iii) because it does not consider reasonable alternatives for avoiding or reducing the environmental impacts of a severe spent fuel accident, i.e., SAMAs. Alternatives that should be considered include re-racking the fuel pool with low-density fuel storage racks and transferring a portion of the fuel to dry storage.

This contention is supported by the expert declarations and reports of Drs. Gordon Thompson and Jan Beyea regarding the likelihood and consequences of spent fuel pool accidents at the Vermont Yankee nuclear power plant. See Exhibits I and 2.

B. Basis for Contention NEPA requires that new and significant information, not considered in any prior EIS for a proposed action, must be considered in a supplemental EIS if(a) the new information arises before the final action is taken, and (b) the new information shows that the environmental impacts of the proposed action would be significantly different than the impacts presented in the EIS. Marsh, supra; 10 C.F.R. § 51.53(c)(3)(iv). Here, significant new information, not previously considered by the NRC in any EIS, shows that the impact of high-density spent fuel pool storage at Vermont Yankee would be significantly greater than contemplated in prior EISs. Therefore the NRC must consider the environmental impacts of a pool accident in a supplemental EIS for the Vermont Yankee license renewal decision.

This contention also meets the standard established in Harrisfor pleading an admissible contention seeking consideration of a severe accident in an EIS, because it presents sufficient information to create a "genuine material dispute of fact or law adequate to warrant further inquiry" into the question of whether the likelihood of a pool 23

fire falls within the range of probability considered reasonably foreseeable by the NRC.

CarolinaPower & Light Co. (Shearon Harris Nuclear Power Plant), LBP-00-19, 52 NRC 85, 97-98 (2000), affirmed on other grounds, CLI-01-1 1, 53 NRC 370 (2001).2 In addition, it meets the standard established in Limerick Ecology Action v. NRC, that a party may litigate the question of whether NEPA requires consideration of the environmental impacts of intentional and malicious acts against a nuclear facility by presenting sufficient evidence to challenge the factual basis for the policy against such consideration. See note 9 above.

1. The potential for a pool fire has not been considered in any previous EIS.

As discussed above in the contention, new information regarding the potential for a pool fire is presented in NUREG-1738, the NAS Report, and the Thompson Report.

All of these documents were written after the issuance of the License Renewal GEIS, and therefore they qualify as "new information" for purposes of requiring a supplemental EIS. As the Court recognized in Hodges v. Abraham, 300 F.3d 432, 447 (41h Cir. 2002),

an agency may review and consider previously issued NEPA documents in determining 13 While the ASLB later ruled that the one accident scenario it selected for litigation in the Harriscase was "remote and speculative" [LBP-01-09, 53 NRC 239, 271], that decision is not dispositive here, by virtue of significant factual differences, including differences in the plants' designs. While Harris is a pressurized water reactor

("PWR"), Vermont Yankee is a boiling water reactor ("BWR"). As a PWR, Harris has two major design features which render it less vulnerable than Vermont Yankee to a pool fire: first, the fuel pools are partially below ground, and second, the pools are in a separate building from the reactor building. In contrast, the pool at Vermont Yankee is above ground, and therefore it is more vulnerable to a breach in the pool wall or floor.

NAS Report at 33. Unlike Harris, the Vermont Yankee pool is also located in the same building as the reactor. Given an early release from the Vermont Yankee reactor as part of a core-melt accident, hot gases and radioactive material from the reactor would spread throughout the building. The radiation field and the thermal environment would be more extreme than would be the case in the Harris pool building if two of the pools in that building were to suffer fires. Thompson Report, § 6.

24

whether to supplement an EIS. Here, the history of NRC's NEPA consideration of spent fuel storage risks shows that although the NRC has been aware of the risks of high-density fuel pool fires for many years, it has not publicly disclosed or analyzed that risk in any EIS. Nor has the NRC updated the License Renewal GElS to address the additional information about the risks of pool fires that has accumulated over the years since publication of the License Renewal GELS. Thus, the NRC has failed to take the "hard look" required by NEPA. Marsh, 490 U.S. at 374.

a. The EIS for the original Vermont Yankee license and other nuclear power plant licenses did not consider impacts of pool accidents.

Since the early 1980's, the EISs for the licensing of all U.S. nuclear plants have considered the potential for severe accidents. This consideration has been based on the findings of the Reactor Safety Study (WASH-1400) (1975). As later summarized by the NRC, the Reactor Safety Study concluded that the risks of beyond design-basis accidents in the low-density spent fuel storage pools in use at that time were "orders of magnitude" below the risks of reactor core accidents, because of the "simplicity of the spent fuel storage pool design." NUREG-1353, Regulatory Analysis for the Resolution of Generic Issue 82, "Beyond Design-basis Accidents in Spent Fuel Pools" at ES-i (April 1989)

("NUREG-1353"). The simple features of low-density spent fuel storage were:

(1) the coolant is at atmospheric pressure, (2) the spent fuel is always subcritical and the heat source is low, (3) there is no piping which can drain the pool and (4) there are no anticipated operational transients that could interrupt cooling or cause criticality.

Id. at ES-1. Thus, the 1972 EIS for the Vermont Yankee plant, where spent fuel initially was stored in low-density racks, had no reason to address the environmental impacts of pool accidents.

25

Shortly after WASH-1400 was published, then-President Carter cancelled the national program for reprocessing of spent fuel, and licensees began to use high-density racks to store an ever-increasing inventory of spent fuel at nuclear power plant sites.

This decision to store an increasing volume of spent fuel onsite led to the use of high-density storage racks, which "results in a larger inventory of fission products in the pool, a greater heat load on the pool cooling system, and less distance between adjacent fuel assemblies." NUREG-1353 at ES-1.

b. The 1979 Sandia Report showed risks of high-density pool storage.

In March of 1979, the NRC published a report by one of its contractors, Sandia National Laboratories, showing that in the case of total, instantaneous drainage of water from a pool, densely packed spent fuel, even a year after discharge, would likely heat up to the point where its zircaloy cladding would burst and then catch fire. Analysis in the report also showed that partial drainage would be a more severe condition, causing older fuel to ignite. 1979 Sandia Report. See Thompson Report, § 2.

c. The 1979 GEIS did not address pool fire risks.

In August of 1979, several months after publishing the 1979 Sandia Report, the NRC issued the 1979 GEIS, which constitutes the only EIS the NRC ever prepared for the specific purpose of evaluating spent fuel storage impacts. Using the assumption that all pool storage space as originally designed had been expanded by re-racking with medium-density or high-density storage racks (see 1979 GEIS at 3-2), the GEIS examined the impacts of fuel storage in pools and found that storage of fuel in pools "has an insignificant impact on the environment." Id.at 8-2.

26

Despite the recent publication of the 1979 Sandia Report, the GEIS made no mention of the potential for a pool fire in high-density fuel storage pools. The GELS' only reference to the 1979 Sandia Report was to cite it as a footnote to the following statement:

Assuming that the spent fuel stored at an independent spent fuel storage installation is at least one year old, calculations have been performed to show that loss of water should not result in fuel failure due to high temperatures ifproper rack design is employed.28

28. "Spent Fuel Heatup Following Loss of Water During Storage," Report NUREG/CR-0649, March 1979.

1979 GElS at 4-21 (emphasis added). But the GEIS did not mention the fact that the only rack design that could have been deemed "proper" by the authors of the 1979 Sandia Report was a low-density rack design, because Sandia had found that fuel stored in a high-density rack would bum if water were lost from the pool.

Thus, the 1979 GElS purported to take account of the 1979 Sandia Study, but actually did not address the known, significant risk implications of the study, thereby failing to satisfy the "hard look" standard for an EIS. Robertson, 490 U.S. at 349; Marsh, 490 U.S. at 374. See also HughesRiver WatershedConservancy v. AgricultureDept.,

81 F.3d 437, 446 (4th Cir. 1996) (holding that in order for an EIS to serve its functions of informing decision-makers and the public, it is "essential" that the EIS not be based on "misleading" assumptions).

d. The 1990 Waste confidence rulemaking ignored the risk of pool fires.

The NRC next addressed the environmental risks of spent fuel storage in the 1990 revision to the Waste Confidence rulemaking, where the agency examined the 27

environmental impacts of storing spent fuel at reactor sites for an additional 30 years pending the opening of a final repository. 1990 Waste Confidence Rulemaking Notice, 55 Fed. Reg. 38474. In response to comments on the potential for spent fuel pool accidents, the Commission asserted that it had spent "several years" studying "in detail" the "catastrophic loss of reactor spent fuel pool water possibly resulting in a fuel fire in a dry pool." 55 Fed. Reg. at 38,481.'4 The NRC made no mention of the 1979 Sandia Report, however, which had found that partial loss of water from a pool posed a more serious risk than complete and instantaneous drainage.

Moreover, while the NRC cited NUREG-1353 (id. at 38,481), it failed to note the observation in NUREG-1353 that: "some laboratory studies have provided evidence of the possibility of fire propagation between assemblies in an air cooled environment."

NUREG-1353 at ES-1. Nor did the NRC respond to the recommendation of NUREG-1353 that the NRC undertake a "re-examination" of the risks of spent fuel pool accidents.

NUREG-1353 at ES-1.

Finally, the NRC asserted that BWR fuel aged over six months would not bum, although NUREG-1353 considered only low- and medium-density BWR racks, not high-density racks (see pp 4-9 to 4-11 of NUREG-1353).

c. The License Renewal GElS merely repeated the inadequate analysis in the 1990 Waste Confidence rulemaking.

14 The NRC also cited a set of technical studies, all of which evaluated a total and instantaneous loss of water from the pool rather than partial water loss:

NUREG/CR-4982, Severe Accidents in Spent FuelPools in Support of GenericIssue 82 (1987); NUREG/CR-5176, Seismic FailureandCask Drop Analysis ofthe Spent Fuel Pools at Two Representative NuclearPower Plants (1989); NUREG/CR-528 1, Value/Impact Analysis ofAccident PreventativeandMitigative Optionsfor Spent Fuel Pools; NUREG-1353, Regulatory Analysisfor the Resolution of Generic Issue 82, Beyond Design-basisAccidents in Spent Fuel Pools (1989). See Thompson Report, § 2.

28

In the rulemaking notice for the license renewal rule, the Commission claimed to have generically considered the environmental impacts of on-site spent fuel storage in the context of the NRC's GETS for license renewal. Final Rule, Environmental Review for Renewal of Nuclear Power Plant Operating Licenses, 61 Fed. Reg. 66,537, 66,538, (December 18, 1996). According to the GETS, the environmental impacts of pool storage of spent fuel are very small. As summarized in an appendix to the NRC's regulations for implementation of NEPA:

The expected increase in the volume of spent fuel from an additional 20 years of operation can be safely accommodated on a site with small environmental effects through dry or pool storage at all plants if a permanent repository or monitored retrievable storage area is not available.

Table B-I of 10 CFR 51, Subpart A, Appendix B to 10 C.F.R. Part 51. See also License Renewal GEIS at 6-83.

The License Renewal GEIS also states that "[c]urrent and potential environmental impacts from spent-fuel storage have been studied extensively and are well understood."

1d. at 6-8 3. But the License Renewal GETS contains no new analysis of thepotential for spent fuel pool accidents, and appears to rely entirely on the 1990 Waste Confidence rulemaking. Id. (referring to "generic determination of no significant environmental impact in [NRC] regulations at 10 CFR 51.23," which was promulgated in the Waste Confidence rulemaking.

2. Only the 1979 GElS has evaluated the environmental impacts of deliberate and malicious acts against spent fuel pools.

The 1979 GEIS contains an appendix which discusses the potential impacts of a deliberate attack on a fuel pool. Id., Appendix J. The GElS postulated an attack by up to 83 adversaries, and damage to between one and 1,000 fuel assemblies by high-explosive 29

charges. But the analysis was insufficient to address the environmental impacts of a deliberate attack on the fuel because it underestimated the potential for a pool fire if the explosives succeeded in lowering the pool's water level.

Since the 1979 GEIS was published, the NRC has declined to consider the impacts of deliberate or malicious acts against fuel pools or any other aspect of nuclear facilities in an EIS, including the License Renewal GEIS. See License Renewal GEIS at 5-18 and discussion above in Section III.B.3.b.

3. Significant new information shows the reasonably foreseeable potential for a pool fire, and that the consequences are high.

Significant new information, not considered by the NRC in any previous EIS, shows that the potential for a severe fire in Vermont Yankee's high-density fuel storage pool is significant and that the consequences of such a fire would be extreme.

a. Significant new information shows that fuel of any age will burn if uncovered.

Significant new information, consisting primarily of the attached Thompson Report and two government-sponsored studies -- NUREG-1738 and the NAS Report --

undermines the conclusion of the NRC's previous EISs that (1) only recently discharged fuel will burn, and (2) complete drainage of a fuel pool is a more severe case than partial drainage. See 1990 Waste Confidence Rulemaking Notice, 55 Fed. Reg. at 38,481. Total or partial loss of water from a fuel pool containing high-density racks will initiate either an air-zirconium reaction or a steam-zirconium exothermic reaction within hours.

Thompson Report, § 2. Once initiated, this reaction could spread to nearby, previously uninvolved, fuel assemblies. A significant fraction of the pool's inventory of radioactive isotopes, notably cesium-137, could be released to the atmosphere and would then travel 30

downwind as a plume, causing extensive environmental contamination. See Beyea Report.

In NUREG-1738, the NRC Staff also reached the conclusion that regardless of the age of the fuel in a pool, the fuel will burn shortly after the tops of the fuel assemblies are uncovered. Id. at 2 2-2. As summarized in the report, adiabatic heatup of the fuel, caused by disruption of the passive cooling process, may cause a radioactive release within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the fuel assemblies are uncovered, even for fuel aged five years. Id.

at 2-2.

In a subsequent study which focused on the vulnerability of fuel pools to attack, a committee of the National Academies of Sciences ("NAS"), which included former NRC official Robert Bernemo, reviewed NUREG-1738 and other more recent studies that followed on the work done in NUREG-1738. While a significant portion of the report was classified, the unclassified portion of the report reported the committee's general conclusions that:

For some scenarios, the fuel could be air cooled within a relatively short time after its removal from the reactor. If a loss-of-coolant event took place before the fuel could be air cooled, however, a zirconium cladding fire could be initiated if no mitigative actions were taken. Such fires could release some of the fuel's radioactive material inventory to the environment in the form of aerosols.

For a partial-loss-of-pool-coolant event, the analysis indicates that the potential for zirconium cladding fires would exist for an even greater time (compared to the complete-loss-of-pool-coolant event) after the spent fuel was discharged from the reactor because air circulation can be blocked by water at the bottom of the pool.

Thermal coupling between circulation can be blocked by water at the bottom of the pool. However, this heat transfer model has been modeled simplistically in the MELCOR runs performed by Sandia.

If the water level is above the top of the fuel racks, decay heat in the fuel could cause the pool water to boil. Once water levels fall below a certain level in the fuel assembly, the exposed portion of the fuel cladding might heat up sufficiently to ignite if no mitigative actions were taken. This could result in the release of a 31

substantial fraction of the cesium inventory to the environment in the form of aerosols.

NAS Report at 53-54 (footnote omitted).

Thus, new information shows the existence of a class of severe pool accident scenarios that have not been previously evaluated or that have been evaluated improperly, either generically or for the Vermont Yankee site.

b. Significant new information shows the credibility of events leading to a fuel pool accident Significant new information also shows that total or partial loss of water from a fuel pool, either through equipment failure or deliberate malicious acts, is not a remote or speculative event. For a variety of scenarios, including external and internal events and deliberate and malicious acts, a severe pool accident is a credible and reasonably foreseeable event. Indeed, the estimated probability for a number of scenarios is within the range considered by the NRC to constitute a design-basis accident, which must not only be discussed in an ER and EIS, but which must be designed against under NRC safety regulations. See Section VII. below.

i. Accidents caused by human error, equipment failure, and natural forces are credible.

As discussed in Section 6 of the attached Thompson report, a number of credible scenarios may lead to a severe accident in the Vermont Yankee fuel pool. Many reactor core melt scenarios would involve the interruption of cooling to the pool. Moreover, the high-radiation field produced by a reactor core accident could initiate or exacerbate a pool fire by precluding the presence and functioning of operating personnel. Making the reasonable assumption that the conditional probability of a pool fire accompanying an early containment release is 50%, the overall estimated likelihood of a pool fire, 32

excluding acts of malice, is on the order of two per 100,000 years (2 x 10-5). This level of probability is well within the range that NRC considers to qualify as a design-basis accident under the PFSl standard, and therefore is cognizable under NEPA.

ii. Accidents caused by intentional malicious acts are credible.

The License Renewal GEIS offers two principal bases for the NRC's refusal to consider the environmental impacts of sabotage, terrorist attacks and other intentional malicious acts in its NEPA review for license renewal: their likelihood is not quantifiable, and that in any event this type of accident is "not reasonably expected."

License Renewal GEIS at 5-18. The position taken by the Commission in the GEIS is consistent with other pronouncements by the NRC. See discussion in Section III.B.3.b above.

Significant new information shows that the Commission's factual basis for refusing to consider the environmental impacts of deliberate and malicious acts in the License Renewal GEIS is no longer viable, and therefore may be challenged in this proceeding under 10 C.F.R. § 51.53(c)(3)(iv). Most significantly, the NRC's assertion that deliberate malicious acts are not "foreseeable" for purposes of preparing an EIS is contradicted by the agency's own response to the events of September 11, which shows not only that the NRC considers terrorist attacks on nuclear facilities to be foreseeable, but that that defending against them is an extremely high priority.

As of September 11, 2001, it is now clear that terrorists are both capable of and intent upon causing major damage to life and property in the United States. As observed by the ASLB in a 2001 decision:

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Regardless of how foreseeable terrorist attacks that could cause a beyond-design-basis accident were prior to the terrorist attacks of September 11, 2001, involving the deliberate crash of hijacked jumbo jets into the twin towers of the World Trade Center in New York City and the Pentagon in the Nation's capital, killing thousands of people, it can no longer be argued that terrorist attacks of heretofore unimagined scope and sophistication against previously unimaginable targets are not reasonably foreseeable. Indeed, the very fact that these terrorist attacks occurred demonstrates that massive and destructive terrorist acts can and do occur and closes the door, at least for the immediate future, on qualitative arguments that such terrorist attacks are always remote and speculative and not reasonably foreseeable.

Duke Cogema Stone and Webster (Savannah River Mixed Oxide Fuel Fabrication Facility), LBP-01-35, 54 NRC 403, 446 (2001), reversed,CLI-02-24, 56 NRC 335 (2002)."

Moreover, as the NRC itself has recognized, the September 11 events were by no means the first sub-national attacks on major strategic targets. Two events in 1993 -- the bombing of the World Trade Center parking garage and the intrusion into the Three Mile Island security area and turbine building by a station wagon - had already prompted the NRC to promulgate a rule protecting nuclear power plants against vehicle bombs. See Final Rule, Protection Against Malevolent Use of Vehicles at Nuclear Power Plants, 59 Fed. Reg. 38,889, 38,891 (August 1, 1994).16 15 In that case, the ASLB admitted a contention seeking NEPA consideration of the environmental impacts of a terrorist attack on a proposed factory for fabrication of plutonium-based nuclear power plant fuel. Although the Commission later reversed the ASLB's decision, the ASLB's comment remains trenchant.

16 Other events of the last two decades include the 1983 bombing of the Marine barracks in Beirut; the 1995 bombing of the Federal Courthouse in Oklahoma City; the 1993 plot to bomb the United Nations Building, FBI offices in New York City, the Lincoln Tunnel, the Holland Tunnel, and the George Washington Bridge; the 1995 release of SARIN nerve gas in the Tokyo subway; the 1998 bombing of the U.S.

embassies in Tanzania and Kenya; the 2002 bombing of the U.S.S. Cole; and the 2004 bombing of commuter trains in Madrid, Spain.

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Since September 11, the NRC has only increased its level of vigilance and preparedness against attacks on nuclear facilities. As summarized by the Chairman of the NRC:

awareness, resources, and vigilance were there [before September 11], but all went to a higher level when 9/11 showed the determination of enemies of the United States to attack our people and our way of life.

Remarks by NRC Chairman Nils J. Diaz to the Joint NRC/DHS State Security Outreach Workshop (June 17, 2003). Thus, in cooperation with the Department of Homeland Security ("DHS"), the NRC established a series of graded threat levels and associated protective measures, whose purpose was to keep the government in a state of readiness to 7

respond to a threat that was now perceived as persistent.'

Moreover, leaders of adversarial sub-national groups have openly admitted that nuclear power stations are near the top of their lists as targets for attacks on civilians in the United States. On October 30, 2001, for example, the Washington Post reported on an interview with a jailed disciple of Osama bin Laden who said there are "more important places, like atomic plants and reactors" that may have been more appropriate targets than the World Trade Center. William Branigan, In Afghan Jail, a TerroristWho Won't Surrender,Washington Post, October 30, 2001.

17 NRC Regulatory Issue Summary 2002-12A, Power Reactors, NRC Threat Advisory and Protective Measures System (August 19, 2002). Notably, the President also has identified nuclear power plants as "key assets" that are "most critical in terms of national-level public health and safety, governance, economic and national security, and public confidence consequences." National Strategy for the Physical Protection of Critical Infrastructures and Key Assets at vii, xii (February 2003). This report can be found on the internet at http://Avwv.whitehouse.gov/pcipb/physical.htmI Other federal agencies have also acknowledged that nuclear power plants are particularly attractive targets because of the widespread health and economic damage they can cause if successfully attacked. As summarized by former FBI Director Robert S. Mueller:

... America is awash in desirable targets- those that are symbolic like the U.S.

Capitol and the White House - as well as the many infrastructural targets, lie nuclear power plants, mass transit systems, bridges, and tunnels, shipping and port facilities, financial centers, and airports - that if successfully hit, would cause both mass casualties and a crippling effect on our economy."

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Thus, after September 11, the NRC began to treat attacks by sub-national adversaries as an inevitable and constant threat requiring perpetual vigilance and preparedness. The NRC's efforts undermine its claim that the potential for such attacks is "remote and speculative." See PFSII,56 NRC at 348-350.

iii. Fuel pools are vulnerable to attack.

A range of means is available to intentionally initiate a pool fire at the Vermont Yankee plant. Thompson Report, § 7 and Table 7-1. Moreover, both the NRC Staff and the National Academies of Sciences have found that spent fuel storage pools are vulnerable to intentional damage. As the NRC Staff conceded in a 2001 memorandum to the Commissioners:

Until recently, the staff believed that the DBT [design-basis threat] of radiological sabotage could not cause a zirconium fire. However, NUREG-1738 does not support the assertion of a lesser hazard to the public health and safety, given the possible consequences of sabotage-included uncovery of the fuel in the SFP when a zirconium-fire potential exists.

SECY-01-0100, Memorandum to the Commissioners from William D. Travers, Executive Director for Operations ("EDO") re: Policy Issues Related to Safeguards, Insurance, and Emergency Preparedness Regulations at Decommissioning Nuclear Power Plants Storing Spent Fuel in Spent Fuel Pools (WITS 200000126) (June 4, 2001),

attachment at 13.Is The memorandum went on to say that the NRC is "conducting detailed analyses of the effects of the DBT of radiological sabotage on SFPs," and that it will "use the results of these analyses to determine, on a plant-specific basis, whether Testimony before the Senate Committee on Intelligence of the United States Senate (February 16, 2005).

18 A zirconium-induced fire potential exists in virtually any high-density spent fuel pool that is filled with fuel, or even partially filled, as is the case at the Vermont Yankee nuclear plant. Thompson Report, § 2.

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radiological sabotage can result in conditions which could lead to zirconium fires at a decommissioning plant." Id. Thus, by embarking on its own investigation into the vulnerability of spent fuel pools to sabotage-included fires, the Staff has effectively conceded that acts of malice against spent fuel are credible and worthy of consideration in the NRC's NEPA decision-making process.

The NAS Report also reports a similar conclusion:

A terrorist attack that either disrupted the cooling system for the spent fuel pool or damaged or collapsed the pool itself could potentially lead to a loss-of-pool-coolant event. The cooling system could be disrupted by disabling or damaging the system that circulates water from the pool to heat exchangers to remove decay heat. This system would not likely be a primary target of a terrorist attack, but it could be damaged as the result of an attack on the spent fuel pool or other targets at the plant (e.g., the power for the pumps could be interrupted.) The loss of cooling capacity would be of much greater concern were it to occur during or shortly after a reactor offloading operation, because the pool would contain a large amount of decay heat.

NAS Report at 48. The NAS committee also evaluated studies of aircraft crashes and assaults on fuel pools using explosives, and reported that:

• .. there are some scenarios that could lead to the partial failure of the spent fuel pool wall, thereby resulting in the partial or complete loss of pool coolant. A zirconium cladding fire could result if timely mitigative actions to cool the fuel were not taken.

NAS Report at 49. Notably, the NAS was not able to give any details in support of its conclusion, but referred instead to a classified report for that information. Id.

c. The NRC has adequate qualitative tools to evaluate the potential for intentional malicious acts against the Vermont Yankee plant.

In the License Renewal GEIS, the NRC asserts its inability to quantify the likelihood of sabotage as a rationale for refusing to address its impacts in an EIS. GEIS at 5-18. The fact that the risk of sabotage may not be easily quantifiable is not an excuse 37

for failing to address it in an EIS, however. As provided in the Council on Environmental Quality's regulations implementing NEPA, 40 C.F.R. § 1502.22, the agency must make an attempt to evaluate reasonably foreseeable significant adverse effects if the costs of obtaining the information are not exorbitant. Even if the costs of obtaining the information are exorbitant, the agency must acknowledge that the information exists but is unavailable, make a statement of the relevance of the information to the evaluation of impacts in the EIS, summarize existing relevant and credible scientific evidence, and provide the agency's evaluation of the impacts based on generally accepted theoretical approaches or research methods. See also 10 C.F.R. § 51.71 ("To the extent that there are important qualitative considerations or factors that cannot be quantified, these considerations or factors will be discussed in qualitative terms.").

In fact, the Commission has already shown itself capable of qualitatively analyzing the potential for intentional destructive acts against nuclear facilities. By proceeding with the 1994 vehicle bomb rulemaking, which was directly responsive to the World Trade Center bombing and the Three Mile Island vehicle intrusion incident, the Commission abandoned its previous position that the difficulty of quantifying the probability of such events means that they can be ignored. While the Vehicle Bomb rule was promulgated under the AEA rather than NEPA, the rationale for the rule is relevant here because it demonstrates that the NRC has the capacity and information necessary to perform a qualitative analysis of the potential for deliberate and malicious acts. In that instance, the NRC performed a "conditional probabilistic risk analysis" to assess the vulnerability of a nuclear power plant to a vehicle bomb. Vehicle Bomb Rule, 59 Fed.

38

Reg. at 38,891. In using the findings of this analysis to develop the vehicle-bomb rule, the NRC took a qualitative approach to assessing the probability of a vehicle-bomb event.

In the preamble to the rule, the Commission explicitly recognized that even if the likelihood of malicious or insane acts cannot be quantified, they may not be ignored:

Over the past several years, a number of National Intelligence Estimates have been produced addressing the likelihood of nuclear terrorism. The analyses and conclusions are not presented in terms of quantified probability but recognize the unpredictable nature of terrorist activity in terms of likelihood. The NRC continues to believe that, although in many cases considerations of probabilities can provide insight into the relative risk of an event, in some cases it is not possible, with current knowledge and methods, to usefully quantify the probability of a specific vulnerability threat.

The NRC notes that, although not quantified, its regulatory analysis recognizes the importance of the perception of the likelihood of an attempt to create radiological sabotage in assessing whether to redefine adequate protection. The NRC's assessment that there is no indication of an actual vehicle threat against the domestic commercial nuclear industry was an important consideration in concluding that neither the Three Mile Island intrusion nor the World Trade Center bombing demonstrated a need to redefine adequate protection.

The NRC does not agree that quantifying the probability of an actual attack is necessary to a judgment of a substantial increase in overall protection of the public health and safety (a less stringent test of the justification of for a rule change). Inherent in the NRC's currentregulationsis apolicy decision that the threat,although not quantified, is likely in a range that warrantsprotection againsta violent external assaultas a matter ofprudence.

59 Fed. Reg. at 38,890-9 (emphasis added). The NRC further elaborated on what it meant by it use of the term "likely," by identifying several factors that make up the "domestic threat environment" and noting the degree to which it had changed in recent years:

The vehicle bomb attack on the World Trade Center represented a significant change to the domestic threat environment that ... eroded [our prior] basis for concluding that vehicle bombs could be excluded from any consideration of the domestic threat environment. For the first time in the United States, a conspiracy with ties to Middle East extremists clearly demonstrated the capability and motivation to organize, plan and successfully conduct a major vehicle bomb 39

attack. Regardless of the motivations or connections of the conspirators, it is significant that the bombing was organized within the United States and implemented with materials obtained on the open market in the United States.

Accordingly, the Commission believes that the threat characterized in the final rule is appropriate.

Id., 59 Fed. Reg. at 38891. These same considerations continue to apply in the post-September 11 environment, and indeed are all the more persuasive of a sea change in the "domestic threat environment." Thus, motive, capacity, and the pattern of past incidents are relevant to a qualitative analysis.

Thus the circumstances of this case satisfy the NRC's qualitative standard for determining that deliberate and destructive acts against the Vermont Yankee spent fuel pool are reasonably foreseeable.

d. Other GEIS grounds for refusing to address impacts of deliberate malicious acts are invalid.

As additional grounds for refusing to consider the environmental impacts of intentional destructive acts, the GEIS asserts that NRC security regulations provide reasonable assurance that the risk from sabotage is small, and that the consequences of an intentionally caused accident would be "no worse than" the consequences of internally initiated events. Id. at 5-18. These rationales are invalid.

First, NEPA's procedural requirements are independent of the AEA, and must be satisfied regardless of an applicant's compliance with NRC regulations for implementation of the AEA. Limerick EcologyAction v. NRC, 869 F.2d at 730.

Second, the radiological consequences of a pool fire would be quite different from the consequences of a reactor accident, and in some respects worse. The principal radioactive isotopes released in a severe reactor accident are generally short-lived, and thus the most important concern in avoiding or mitigating those impacts is to evacuate 40

people as quickly as possible from the area. In contrast, the principal radioactive isotope released by a pool fire consists of cesium-137, which has a half-life of 30 years.19 Immediate evacuation is still an important consideration, but long-term land contamination is an additional factor that must be planned for. The land area affected by a radiological release from a pool fire could be contaminated for decades, requiring permanent relocation of entire communities and their associated businesses, farms and institutions.

Moreover, the area of land contaminated by a release could be much larger for a pool fire than a reactor accident because the inventory of radioactivity that may be released from a pool is so much larger than the inventory of radioactivity that may be released from the core. As demonstrated in Table 3-3 of the Thompson Report, much more radioactive material is held in the pool than in the core.

In any event, even assuming for purposes of argument that the consequences of a reactor accident and a pool accident were the same, the SAMAs appropriate for each type of accident would be different. In considering the environmental impacts of sabotage, it is particularly important to consider SAMAs which could mitigate the impacts of sabotage. Using a combination of low-density wet storage and dry storage would virtually eliminate the vulnerability of the Vermont Yankee fuel pool to attack. See Thompson Report, § 8. Thus, NEPA requires a discussion of the environmental impacts of a pool fire, regardless of whether a pool fire's impacts would be bounded by the impacts of a reactor accident.

19 While the reactor core contains cesium-137, the quantity is much smaller than the quantity of cesium-137 contained in the pool. Thompson Report, § 3.

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e. NRC's policy rationales in PFSII and Diablo Canyon are not supported.

In the PFSHI and Diablo Canyon decisions, the Commission gave a number of policy and fact-based rationales for refusing to consider the environmental impacts of deliberate and malicious acts in its NEPA decisions. Petitioner will respond to them in this section of the contention.

In Diablo Canyon and PFSH,the Commission argued that the possibility of a terrorist attack is "too far removed from the natural or expected consequences of agency action to require a study under NEPA." Diablo Canyon, 57 NRC at 6-7, quoting PFS II, 56 NRC at 349. This argument must be rejected because it "runs counter to the evidence before the agency." Southwest Center v. U.S. ForestService, 100 F.3d 1443, 1448 (9th Cir. 1996). In particular, the argument ignores the federal government's own determinations that nuclear facilities are highly attractive targets to terrorists, as well as the NRC's own actions demonstrating how seriously it takes the threat.

The Commission's ruling also is inconsistent with the agency's own long-established policy and practice of addressing the environmental impacts of external events in accident analyses conducted under NEPA. Sierra Club v. NRC, 862 F.2d 222, 228 (9 th Cir. 1988) (reversing a decision that was "contrary to the NRC's own policy (and one that accords with common sense)"). Under its own NEPA guidance, NRC considers accidents caused or exacerbated by a range of initiating events, including internal events (such as equipment failure) and external events (such as tornados, floods, earthquakes, and explosions at adjacent facilities). NUREG-1555, Environmental Standard Review Plan for Environmental Review for Nuclear Power Plants at 7.2-3 (October 1999). None of these external events would constitute "natural" consequences of operation of the 42

Vermont Yankee nuclear power plant. If they were to occur while the plant is operating, however, they could cause an accidental release of radioactivity to the environment, which would not have occurred had the nuclear facility not been licensed.20 In Diablo Canyon and PFSII,the Commission also argued that inquiries into the environmental impacts of terrorist attacks are not "manageable." Diablo Canyon, 57 NRC at 6-7, and PFSII, 56 NRC at 349 and note 33, quoting MetropolitanEdison Co. v.

People Against NuclearEnergy, 460 U.S. 766, 776 (1983). According to the NRC, those who seek a NEPA evaluation of the environmental impacts of terrorist attacks effectively seek an open-ended, "worst-case" analysis that has "no stopping point." PFS11, 56 NRC at 354.

The Commission's citation to MetropolitanEdison Co. v. People Against Nuclear Energy is completely inapposite. In that case, the Supreme Court ruled that psychological effects posed by the risk of an accident at the Three Mile Island nuclear power plant were "too remote from the physical environment" to warrant preparation of an EIS. 460 U.S. at 774. The Supreme Court "emphasize[d]" that it was considering, in that case, "the effects caused by the risk of an accident." Id. (emphasis added). Here, in contrast, Petitioner is concerned about actual physical environmental effects in the event 20 In a footnote to PFSII,the Commission attempted to distinguish "natural" events from terrorist attacks on the ground that natural events are "closely linked to the natural environment of the area within which a facility will be located, and are reasonably predictable by examining weather patterns and geological data for that region." 56 NRC at 347, note 18. Attacks on nuclear facilities, however, are also "closely linked" to those facilities, in the sense that they are desirable targets. Furthermore, the Commission's argument that natural events are "reasonably predictable" amounts to a reprise of the claim that environmental impacts must be quantifiable in order to be cognizable. See Limerick Appeal BoardDecision, 22 NRC at 701. As discussed above in Section V.B.3.c, the Commission itself disavowed this position in the Vehicle Bomb Rule.

Finally, the Commission's position is inconsistent with 10 C.F.R. § 51.71, which requires a discussion of qualitative factors that cannot be quantified.

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of a terrorist attack on the Vermont Yankee fuel pool. As the Court recognized in MetropolitanEdison, "[t]he situation where an agency is asked to consider effects that will occur if a risk is realized, for example, if an accident occurs at TMI-1, is an entirely different case," where its holding would not apply. Id. at 775.

In any event, the Commission's argument is directly contradicted by the agency's own pragmatic approach to evaluating the potential for specific types of terrorist attacks, as outlined in the 1994 Vehicle Bomb Rule. The Vehicle Bomb Rule demonstrates that it is possible to evaluate the potential for and credibility of attack scenarios, and to identify a range of reasonable alternatives for avoiding or mitigating the impacts of such attacks.

Here, the Attorney General seeks a hearing on whether just such an analysis is required for the Vermont Yankee license renewal decision, including a full discussion of the potential consequences of a range of credible events involving destructive intentional acts against the Vermont Yankee spent fuel pool. The Attorney General also seeks an evaluation of a range of reasonable alternatives to the proposed action, including combined low-density pool storage and dry storage. It is only common sense that the analysis requested by Petitioner is no more open-ended than the analysis the NRC performed in promulgating the Vehicle Bomb Rule.

In the Diablo Canyon decision, the Commission also attempted to justify its exclusion of the Petitioners' environmental contentions on the ground that "NEPA's public process is not an appropriate forum for considering sensitive security issues."

CLI-03-01, 57 NRC at 7. The Commission cited no legal basis, however, that would excuse it from compliance with NEPA. Without a specific and conflicting statutory basis, the mere sensitivity of information does not provide an excuse for noncompliance 44

with NEPA. Compliance with NEPA is required "unless specifically excluded by statute or existing law makes compliance impossible." Limerick Ecology Action v. NRC, 869 F.2d at 729, citing Public Service Co. ofNew Hampshire v. NRC, 582 F.2d 77, 81 (1st Cir.), cert. denied, 439 U.S. 1046 (1978). See also FlintRidge Development Corp. v.

Scenic Rivers Association of Oklahoma, 426 U.S. 776, 787-88 (1976).

Moreover, to the extent that the Commission is bound by legal requirements to protect sensitive information, the Commission has failed to demonstrate that those requirements render it "impossible" to consider the environmental impacts of deliberate and malicious against the Vermont Yankee fuel pool. In fact, the Commission's position is inconsistent with its own practice under another public participation statute, Section 189a of the AEA. 42 U.S.C. § 2239. The NRC has never denied a licensing hearing simply because sensitive, proprietary, or safeguards information may be discussed in the hearing. Instead, it implements procedures that limit access to sensitive information to parties who have signed confidentiality agreements.21 The NRC can also use these procedures to limit access to sensitive information regarding the vulnerability of the Vermont Yankee fuel pool to the parties and interested government participants. The Commission also failed to recognize that it can solicitpublic comment, even if it does not disclose all the details of its environmental analysis. State and local governments, which have expertise in and responsibility for implementing back-up security and emergency response measures, also have valuable contributions to make to the decision-making 21 See, e.g, 10 C.F.R. §§ 2.744(e) (procedures for handling safeguards information in NRC hearings), 10 C.F.R. Part 2 Subpart I (procedures for handling classified information in NRC hearings); Pacific Gas & Electric Company (Diablo Canyon Nuclear Power Plant), ALAB-410, 5 NRC 1398, 1405 (1977) (granting intervenor's security expert access to confidential security plans during the operating license proceeding for Diablo Canyon).

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process.

Finally, the NRC ignores the fact that in numerous instances, other agencies such as the U.S. Department of Energy ("DOE") have prepared EISs containing information that was not accessible to the general public.2 2 In none of these instances did the DOE refuse to prepare an EIS because it would involve the discussion of sensitive information.

Instead, the publicly available version of the EIS redacted sensitive information. By following appropriate procedures and obtaining appropriate clearances, interested citizens and state and local governments may gain access to the information.

Finally, in Diablo Canyon, the Commission asserted that its refusal to prepare an EIS on the environmental impacts of a terrorist attack "comports with the practical 22 For instance, the DOE has restricted circulation of some sensitive information, and withheld other information under the classification of "Official Use Only."For example, Appendix H of the DOE's EIS for the proposed Yucca Mountain high-level radioactive waste repository, which discusses consequences of accidents at the repository, is not in the hard copy of the EIS that was circulated to the public, nor is it on the internet. DOE/EIS-0250F, Final Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada at H-i (February 2002). Instead, it was placed in Volume 4 of the Final EIS, which must be specially ordered from the DOE. Id., Readers Guide at 3.

Another EIS prepared by the DOE contains an air transportation accident analysis that is not published in the publicly available version of the EIS, but is contained in an "Official Use Only document." DOE/EIS-236-S2, Draft Supplemental Programmatic Environmental Impact Statement on Stockpile Stewardship and Management for a Modern Pit Facility, Vol. II at C-15 and Tables C.4-I, C.4-2, C.4-3 (May 2003).

The DOE has also prepared EISs containing highly sensitive classified information. See, e.g., DOE/EIS-0161, Final Programmatic Environmental Impact Statement for Tritium Supply and Recycling, Vol. I at 2-1 (October 1995) (evaluating environmental impacts of recycling and production of tritium for nuclear weapons);

DOE/EIS-0319, Final Environmental Impact Statement for the Proposed Relocation of Technical Area 18 Capabilities and Materials at the Los Alamos National Laboratory at iii, 5-1 (August 2002) (evaluating environmental impacts of sabotage on a DOE research facility).

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realities of spent fuel storage and the congressional policy to encourage utilities to provide for spent fuel storage at reactor sites pending construction of a permanent repository." CLI-03-01, 57 NRC at 7. Nothing in the Nuclear Waste Policy Act, however, exempts spent fuel storage from the requirements of NEPA. In fact, the statute specifically requires that the Commission's actions must be consistent with NEPA. 42 U.S.C. § 10152.

4. The consequences of a pool fire are different and potentially more severe than the consequences of a reactor accident.

It is important to consider the environmental impacts of a pool fire, because pool fire impacts are fundamentally different than the impacts of a reactor accident, and therefore have different implications for the consideration of alternatives. See discussion above in Section V.B.3.b.iv.

5. The ER and the EIS must discuss reasonable and feasible alternatives for avoiding or mitigating a pool fire.

As discussed above in Sections III.B. L.c and I1I.B.3.d, NEPA and the NRC's implementing regulations require the consideration of reasonable alternatives to the proposed action, including SAMAs for avoiding or mitigating the consequences of severe accidents. A range of options is available for reducing or avoiding the impacts of a pool fire, including returning the plant to its original design configuration of low-density pool storage of spent fuel and placing excess spent fuel in dry storage. Thompson Report, § 8.

This option would allow the pool to survive a loss of water without damage to the fuel, thus avoiding a pool fire. Id. The technologies of low-density storage and dry storage are reasonable and feasible, and therefore should be considered. Idaho Conservation League v. Mumma, 956 F.2d 1508, 1519-20 (9th Cir. 1992).

47

.¸ I I VI. PETITION FOR IMPOSITION OF BACKFIT ORDER As discussed above in Section III.A.1, the AEA, implementing regulations, and NRC precedents require the NRC to ensure that operation of the Vermont Yankee nuclear power plant does not pose an undue risk to public health and safety during the license renewal term. As the Commission observed in the preamble to the final license renewal rule, the purpose of the rule is to "ensure that operation during the period of extended operation is not inimical to the public health and safety." 56 Fed. Reg. at 64,945. See also Petitionfor Emergency and Remedial Action, 7 NRC at 404, citing Power Reactor Development Corp., 367 U.S. at 402.

One of the NRC's key measures for ensuring adequate protection of the public is to require that its licensed facilities be designed against "design-basis accidents." See discussion above in section III.A.2. The NRC requires that reactor core accidents with a "realistic probability" (i.e., a non-conservative probability) of at least one in ten million per year (10"7) must be included in the design-basis. PFS1,54 NRC at 259-60. By the reasoning of PFSI, the same threshold of probability should be set for pool accidents, because they also have a large source term (i.e., inventory of radioactive material) that may be released by the driving force of the high heat of a fire.2 3 As discussed above in 23 In the PFSldecision, the Commission chose a "threshold" probability of 10.6 for a design-basis accident at an independent spent fuel storage installation, rather than the 10.7 factor used for nuclear power plants. As the Commission explained, the difference in threshold probabilities for design-basis accidents for these two types of facilities is based on the significant difference in the potential consequences of an accident:

The Commission has previously recognized that the 'public health and safety risks posed by ISFSI storage.., are very different from the risks posed by the safe irradiation of the fuel assemblies in a commercial nuclear reactor, which requires the adequate protection of the public ... in the conditions of high temperature and pressures under which the reactor operates.' ... This is because 48

I (~ )

Section V.B.3.b and as demonstrated in the Thompson Report, §§ 6, 7, and 9, the frequencies for a range of spent fuel pool accident precursors fall well above the estimated probability level considered by the NRC to establish the "threshold" for a design-basis event. PFSI, 54 NRC at 259-60.24 There was no need to design against pool fire accidents at the time of initial licensing of Vermont Yankee in 1972, when the former licensee used open low-density racks to store a much smaller quantity of spent fuel. Now that the Vermont Yankee pool has been re-designed to include high-density storage racks, the design of the Vermont Yankee plant poses an undue safety risk of a pool fire. Therefore, pursuant to 10 C.F.R.

§ 50.109(a)(5), the Commission should require the backfitting of the Vermont Yankee nuclear plant by returning the pool to its original low-density storage configuration and using dry storage for any excess fuel.

While current NRC regulations do not appear to provide for an adjudicatory hearing on the adequacy of any design changes ordered by the NRC, it is a subject on the danger presented by irradiated fuel 'is largely determined by the presence of a driving force behind dispersion,' such as heat and pressure neither of which is present in an ISFSI. .... Moreover, the radiological source term is lower at an ISFSI than at a reactor both because the spent fuel has decayed over time prior to placement in an ISFSI and because there are fewer fuel assemblies in an individual cask than in reactor.

54 NRC at 265. [footnotes omitted]. As with a reactor accident, the "driving force," of the heat from a pool fire may disperse a very large amount of radioactive material into the environment. See Thompson Report, § 2. Thus, a pool accident is comparable to, and may in some cases be more severe than, the consequences of a reactor core melt accident.

24 In fact, the majority of accidents analyzed in NUREG-1150 fall well within the range of probabilities considered by the NRC to qualify as design-basis accidents.

See Figure 8.6 of NUREG-1 150, for example, which shows that both the median and the average core damage frequency for internal and external events at the Peach Bottom nuclear power plant (a BWR like Vermont Yankee) fall between 10"3 and 10"5. This core damage frequency is at least two orders of magnitude above the NRC's threshold probability for a design-basis accident at a nuclear plant.

49

.A , I I.

which the NRC should take comment from the interested public because a variety of potential measures for reducing spent fuel pool fire risks are available, with varying degrees of effectiveness. See Thompson Report, § 8. Thus, the Attorney General seeks a discretionary hearing on the adequacy of the design modifications proposed by the 25 Commission.

The choice of design measures could also have a significant impact on the quality of the human environment if the NRC chooses a design measure that is not adequate to prevent the risk of a fire. Thus, the Commission must comply with NEPA by publishing its proposed design measures in the draft EIS for renewal of the Vermont Yankee license.

Such design measures are required by the Atomic Energy Act in order to ensure that during the license renewal term operation of the Vermont Yankee nuclear plant and associated fuel pool poses no undue risk to public health and safety. 42 U. 42 U.S.C. § 2133(d).

VII. CONCLUSION For these reasons, the Commission should grant Petitioner a hearing regarding the issues raised in his contention. In addition, the Commission should initiate a proceeding for the backfitting of the Vermont Yankee nuclear power plant to protect against a design-basis accident involving a fire in the fuel pool.

25 In contrast, the Attorney General has the statutory right under NEPA to a hearing on the environmental contention raised in Section V of this pleading.

50

. P '01 Respectfully submitted, COMMONWEALTH OF MASSACHUSETTS By its Attorneys, THOMAS F. REILLY ATTORNEY GENERAL jane Curran Harmon Curran, Spielberg & Eisenberg, L.L.P.

1726 M Street N.W., Suite 600 Washington, D.C. 20036 202/328-3500 dcurran(iharmoncurran.com Matthew Brock, Assistant Attorney General Environmental Protection Division Office of the Attorney General One Ashburton Place Boston, MA 02108 617/727-2200 matthew.brock(aago.state.ma.us May 26, 2006 51

.4.

• CERTIFICATE OF SERVICE I certify that on May 26, 2005, copies of the foregoing request for hearing, petition to intervene, and petition for a backfit order, were served on the following in the manner described below:

BY HAND:

Office of the Secretary U.S. Nuclear Regultory Commission 11555 Rockville Pike Rockville, MD 20852 Office of the General Counsel U.S. Nuclear Regultory Commission 11555 Rockville Pike Rockville, MD 20852 BY FEDERAL EXPRESS:

Terence A. Burke, Esq.

Entergy Nuclear 1340 Echolon Parkway Mail-Stop M-ECH-62 Jackson, MS 39213 iane Curran

A .

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE COMMISSION In the Matter of )

)

Entergy Nuclear Operations, Inc. ) Docket No. 50-271

)

(Vermont Yankee )

Nuclear Power Station) )

DECLARATION OF DR. GORDON THOMPSON IN SUPPORT OF MASSACHUSETTS ATTORNEY GENERAL'S CONTENTION AND PETITION FOR BACKFIT ORDER I, Gordon Thompson, declare as follows:

1. I am the executive director of the Institute for Resource and Security Studies (IRSS), a nonprofit, tax-exempt corporation based in Massachusetts. Our office is located at 27 Ellsworth Avenue, Cambridge, MA 02139. IRSS was founded in 1984 to conduct technical and policy analysis and public education, with the objective of promoting peace and international security, efficient use of natural resources, and protection of the environment. I am also a research professor at the George Perkins Marsh Institute, Clark University, Worcester, Massachusetts.

2. In support of the Massachusetts Attorney General's request for a hearing, petition to intervene, and backfit petition with respect to the license renewal proceeding for the Vermont Yankee nuclear power plant, I have prepared a report entitled "Risks and Risk-Reducing Options Associated with Pool Storage of Spent Nuclear.Fuel at the Pilgrim and Vermont Yankee Nuclear Power Plants" (25 May 2006). In preparing my report, I reviewed the 25 January 2006 license renewal application filed by Entergy Nuclear Operations, Inc. (Entergy). I have also reviewed various correspondence and technical documents relating to the proposed license amendment and to risks of spent fuel storage, which are identified in the Attorney General's contention and in my Report.

3. The technical factual statements in my report are true and correct to the best of my knowledge, and the technical opinions expressed therein are based on my best professional judgment.

4. I am an expert in the area of technical safety, security and environmental analysis related to nuclear facilities. My Curriculum Vitae is provided here as Attachment A.

5. I received an undergraduate education in science and mechanical engineering at the

2 University of New South Wales, in Australia. Subsequently, I pursued graduate studies at Oxford University and received from that institution a Doctorate of Philosophy in mathematics in 1973, for analyses of plasmas undergoing thermonuclear fusion. During my graduate studies I was associated with the fusion research program of the UK Atomic Energy Authority. My undergraduate and graduate work provided me with a rigorous education in the methodologies and disciplines of science, mathematics, and engineering.

6. Since 1977, a significant part of my work has consisted of technical analyses of safety, security and environmental issues related to nuclear facilities. These analyses have been sponsored by a variety of nongovernmental organizations and local, state and national governments, predominantly in North America and western Europe. Drawing upon these analyses, I have provided expert testimony in legal and regulatory proceedings, and have served on committees advising US and UK government agencies. To illustrate my expertise, I provide more detailed information on my experience below.

7. I have conducted, directed, and/or participated in a number of studies that evaluated aspects of the design and operation of nuclear power plants with respect to severe accident probabilities and consequences. These include general studies and studies of individual plants. For instance, with respect to general studies, in 1986, I participated in the preparation of a study by the Union of Concerned Scientists of the potential for escape of radioactive material during a reactor core-melt accident (Sholly and Thompson, 1986). In the late 1980s, I was part of a team of four scientists which prepared a comprehensive critique of the state of the art of probabilistic risk assessment (PRA) for Greenpeace International (Hirsch et al, 1989). I published two chapters on the relevance of PRA to emergency planning in a book entitled Preparingfor NuclearPowerPlant Accidents (Golding, et al., 1995). All of these studies required me to be highly familiar with the design and operation of nuclear power plants, as well as the characteristics of probabilistic risk assessment.

8. I have also done considerable work on the risks posed by individual nuclear facilities.

In addition to performing the studies described elsewhere in this Declaration, I have studied the risks posed by the Seabrook and Harris plants (U.S.), the La Hague facility (France), and the Darlington and Pickering Stations (Canada). All of these studies required me to become familiar with the relevant details of the design and operation of the facilities involved.

9. To a significant degree, my work has been accepted or adopted by the governmental agencies involved. During the period 1978-1979, for example, I served on an international review group commissioned by the government of Lower Saxony (a state in Germany) to evaluate a proposal for a nuclear fuel cycle center at Gorleben. I led the subgroup that examined accident and security risks and alternative options with lower risk. One of the risk issues that I identified and analyzed was the potential for an exothermic reaction of fuel cladding in a high-density fuel pool if water is lost. I identified partial loss of water as a more severe condition than total loss of water. I identified and described alternative fuel storage options with lower risk. The Lower Saxony government accepted my findings and ruled that high-density pool storage was not an acceptable option at

a - L 3

Gorleben. As a direct result, policy throughout Germany has been to use dry storage, rather than high-density pool storage, for away-from-reactor storage of spent fuel.

10. My work has also influenced decision making by safety officials in the U.S.

Department of Energy (DOE). During the period 1986-1991, I was commissioned by environmental groups to assess the safety of the military production reactors at the Savannah River Site, and to identify and assess alternative options for the production of tritium for the US nuclear arsenal. Initially, much of the relevant information was classified or otherwise inaccessible to the public. Nevertheless, I addressed safety issues through analyses that were recognized as accurate by nuclear safety officials at DOE. I eventually concluded that the Savannah River reactors could not meet the safety objectives set for them by DOE. DOE subsequently reached the same conclusion. The current national policy for tritium production is to employ commercial reactors, an option that I had concluded was technically attractive but problematic from the perspective of nuclear weapons proliferation.

11. In 1977, and again during the period 1996-2000, I examined the safety of nuclear fuel reprocessing and liquid high-level waste management facilities at the Sellafield site in the UK. My investigation in the latter period was supported by a consortium of local governments in Ireland and the UK, and my findings were presented at briefings in the UK and Irish parliaments. I identified safety issues that were not addressed in any publicly available literature about the Sellafield site. As a direct result of my investigation, the UK Nuclear Installations Inspectorate (NII) required the operator of the Sellafield site to conduct extensive safety analyses. These analyses confirmed the significance of the safety issues that I identified, and the NII imposed a schedule for run-down of the Sellafield inventory of liquid high-level waste.

11. In 2000, the NRC Staff accepted my view that older fuel in a spent-fuel pool is more vulnerable to ignition in a state of partial drainage than in a state of total drainage, because convective heat transfer is suppressed by the presence of residual water at the base of the fuel assemblies. Although the NRC Staff previously ignored or disparaged my opinion, the Staff eventually confirmed the validity of my expert opinion on the matter.

12. I am prepared to testify as an expert witness on behalf of the Massachusetts Attorney General with respect to the facts and opinions set forth in my Report.

a -

4 I declare, under penalty of perjury, that the foregoing facts provided in my Declaration are true and correct to the best of my knowledge and belief, and that the opinions expressed herein are based on my best professional judgment.

Executed on 25 May 2006.

Gordon Thompson

I - L.

Curriculum Vitae for Gordon R. Thompson November 2005 Professional expertise

• Technical and policy analyst in the fields of energy, environment, sustainable development, and international security.

Current appointments

• Executive director, Institute for Resource & Security Studies (IRSS), Cambridge, Massachusetts (since 1984).

• Research Professor, George Perkins Marsh Institute, Clark University, Worcester, Massachusetts (since 2002).

Education "D.Phil., applied mathematics, Oxford University (Balliol College), 1973.

"B.E., mechanical engineering, University of New South Wales, Sydney, Australia, 1967.

- B.Sc., mathematics & physics, University of New South Wales, 1966.

Proiect sponsors and tasks (selected)

- California Energy Commission, 2005: conducted technical analysis and participated in expert workshop regarding safety and security of commercial nuclear facilities.

- Committee on Radioactive Waste Management (a committee appointed by the UK government), 2005: provided expert advice on safety and security of radioactive waste management.

• Legal Resources Centre, Cape Town, South Africa, 2004-2005: conducted technical analysis regarding the proposed South African pebble bed modular reactor.

• STAR Foundation, New York, 2002-2004: reviewed planning and actions for decommissioning of research reactors at Brookhaven National Laboratory.

- Attorney General of Utah, 2003: conducted technical analysis and prepared expert testimony regarding a proposed national storage facility for spent nuclear fuel.

• Mothers for Peace, California, 2002-2004: analyzed risk issues and prepared expert testimony associated with the Diablo Canyon nuclear power plant.

• Citizens Awareness Network, Massachusetts, 2002-2003: conducted analysis on robust storage of spent nuclear fuel.

- Tides Center, California, 2002-2004: conducted analysis for the Santa Susana Field Laboratory (SSFL) Advisory Panel regarding the history of releases of radioactive material from the SSFL.

Curriculhm Vitaefor Gordon R. Thompson November 2005 Page 2 Orange County, North Carolina, 1999-2002: assessed risk issues associated with the Harris nuclear power plant, identified risk-reduction options, and prepared expert testimony.

• William and Flora Hewlett Foundation and other sponsors, 1999-2005: performed research and project development for conflict-management projects, through IRSS's International Conflict Management Program.

- STAR Foundation, New York, 2000-2001: assessed risk issues associated with the Millstone nuclear power plant, identified risk-reduction options, and prepared expert testimony.

- Massachusetts Water Resources Authority, 2000: evaluated risks associated with water supply and wastewater systems that serve greater Boston.

- Canadian Senate, Energy & Environment Committee, 2000: reviewed risk issues associated with the Pickering Nuclear Generating Station.

- Greenpeace International, Amsterdam, 2000: reviewed impacts associated with the La Hague nuclear complex in France.

• Government of Ireland, 1998-2001: developed framework for assessment of impacts and alternative options associated with the Sellafield nuclear complex in the UK.

- Clark University, Worcester, Massachusetts, 1998-1999: participated in confidential review of outcomes of a major foundation's grants related to climate change.

- UN High Commissioner for Refugees, 1998: developed a strategy for conflict management in the CIS region.

- General Council of County Councils (Ireland), W. Alton Jones Foundation (USA), and Nuclear Free Local Authorities (UK), 1996-2000: assessed safety and economic issues of nuclear fuel reprocessing in the UK; assessed alternative options.

- Environmental School, Clark University, Worcester, Massachusetts, 1996: session leader at the Summer Institute, "Local Perspectives on a Global Environment".

• Greenpeace Germany, Hamburg, 1995-1996: a study on war, terrorism and nuclear power plants.

• HKH Foundation, New York, and Winston Foundation for World Peace, Washington, DC, 1994-1996: studies and workshops on preventive action and its role in US national security planning.

• Carnegie Corporation of New York, Winston Foundation for World Peace, Washington, DC, and others, 1995: collaboration with the Organization for Security and Cooperation in Europe to facilitate improved coordination of activities and exchange of knowledge in the field of conflict management.

• World Bank, 1993-1994: a study on management of data describing the performance of projects funded by the Global Environment Facility (joint project of IRSS and Clark University).

- International Physicians for the Prevention of Nuclear War, 1993-1994: a study on the international control of weapons-usable fissile material.

- Government of Lower Saxony, Hannover, Germany, 1993: analysis of standards for radioactive waste disposal.

• University of Vienna (using funds supplied by the Austrian government), 1992: review of radioactive waste management at the Dukovany nuclear power plant, Czech Republic.

Curriculum Vitaefor GordonR. Thompson November 2005 Page 3

• Sandia National Laboratories, 1992-1993: advice to the US Department of Energy's Office of Foreign Intelligence.

• US Department of Energy and Battelle Pacific Northwest Laboratories, 1991-1992:

advice for the Intergovernmental Panel on Climate Change regarding the design of an information system on technologies that can limit greenhouse gas emissions (joint project of IRSS, Clark University and the Center for Strategic and International Studies).

• Winston Foundation for World Peace, Boston, Massachusetts, and other funding sources, 1992-1993: development and publication of recommendations for strengthening the International Atomic Energy Agency.

- MacArthur Foundation, Chicago, Illinois, W. Alton Jones Foundation, Charlottesville, Virginia, and other funding sources, 1984-1993: policy analysis and public education on a "global approach" to arms control and disarmament.

• Energy Research Foundation, Columbia, South Carolina, and Peace Development Fund, Amherst, Massachusetts, 1988-1992: review of the US government's tritium production (for nuclear weapons) and its implications.

• Coalition of Environmental Groups, Toronto, Ontario (using funds supplied by Ontario Hydro under the direction of the Ontario government), 1990-1993: coordination and conduct of analysis and preparation of testimony on accident risk of nuclear power plants.

• Greenpeace International, Amsterdam, Netherlands, 1988-1990: review of probabilistic risk assessment for nuclear power plants.

• Bellerive Foundation, Geneva, Switzerland, 1989-1990: planning for a June 1990 colloquium on disarmament and editing of proceedings.

• Iler Research Institute, Harrow, Ontario, 1989-1990: analysis of regulatory response to boiling-water reactor accident potential.

- Winston Foundation for World Peace, Boston, Massachusetts, and other funding sources, 1988-1989: analysis of future options for NATO (joint project of IRSS and the Institute for Peace and International Security).

• Nevada Nuclear Waste Project Office, Carson City, Nevada (via Clark University),

1989-1990: analyses of risk aspects of radioactive waste management and disposal.

- Ontario Nuclear Safety Review (conducted by the Ontario government), Toronto, Ontario, 1987: review of safety aspects of CANDU reactors.

- Washington Department of Ecology, Olympia, Washington, 1987: analyses of risk aspects of a proposed radioactive waste repository at Hanford.

- Natural Resources Defense Council, Washington, DC, 1986-1987: preparation of expert testimony on hazards of the Savannah River Plant, South Carolina.

• Lakes Environmental Association, Bridgton, Maine, 1986: analysis of federal regulations for disposal of radioactive waste.

• Greenpeace Germany, Hamburg, 1986: participation in an international study on the hazards of nuclear power plants.

• Three Mile Island Public Health Fund, Philadelphia, Pennsylvania, 1983-1989: studies related to the Three Mile Island nuclear power plant and emergency response planning.

• Attorney General, Commonwealth of Massachusetts, 1984-1989: analyses of the safety of the Seabrook nuclear power plant, preparation of expert testimony.

- Union of Concerned Scientists, Cambridge, Massachusetts, 1980-1985: studies on energy demand and supply, nuclear arms control, and the safety of nuclear installations.

Curriculum Vitae for GordonR. Thompson November 2005 Page 4

- Conservation Law Foundation of New England, Boston, Massachusetts, 1985:

preparation of expert testimony on cogeneration potential at a Maine paper mill.

• Town & Country Planning Association, London, UK, 1982-1984: coordination and conduct of a study on safety and radioactive waste implications of the proposed Sizewell nuclear power plant, testimony to the Sizewell Public Inquiry.

• US Environmental Protection Agency, Washington, DC, 1980-1981: assessment of the cleanup of Three Mile Island Unit 2 nuclear power plant.

• Center for Energy & Environmental Studies, Princeton University, Princeton, New Jersey, and Solar Energy Research Institute, Golden, Colorado, 1979-1980: studies on the potentials of renewable energy sources.

- Government of Lower Saxony, Hannover, Federal Republic of Germany, 1978-1979:

coordination and conduct of studies on safety and security aspects of the proposed Gorleben nuclear fuel cycle center.

Other experience (selected)

• Principal investigator, project on "Exploring the Role of 'Sustainable Cities' in Preventing Climate Disruption", involving IRSS and three other organizations, 1990-1991.

"Visiting fellow, Peace Research Centre, Australian National University, 1989.

"Principal investigator, Three Mile Island emergency planning study, involving IRSS, Clark University and other partners, 1987-1989.

• Co-leadership (with Paul Walker) of a study group on nuclear weapons proliferation, Institute of Politics, Harvard University, 1981.

• Foundation (with others) of an ecological political movement in Oxford, UK, which contested the 1979 Parliamentary election.

- Conduct of cross-examination and presentation of expert testimony, on behalf of the Political Ecology Research Group, at the 1977 Public Inquiry into proposed expansion of reprocessing capacity at Windscale, UK.

• Conduct of research on plasma theory (while a D.Phil candidate), as an associate staff member, Culham Laboratory, UK Atomic Energy Authority, 1969-1973.

• Service as a design engineer on coal-fired power plants,.New South Wales Electricity Commission, Sydney, Australia, 1968.

Publications (selected)

• Reasonably ForeseeableSecurity Events: Potentialthreats to optionsfor long-term management of UK radioactivewaste, a report for the UK Committee on Radioactive Waste Management, 2 November 2005.

• "Plasma, policy and progress", The AustralianMathematicalSociety Gazette, Volume 32, Number 3, 2005, pp 162-168.

• "A Psychosocial-Healing Approach to Post-Conflict Reconstruction" (with Paula Gutlove), Mind & Human Interaction,Volume 14, Number 1, 2005, pp 35-63.

• "Designing Infrastructure for New Goals and Constraints", Proceedings of the conference, Working Together: R&D Partnershipsin HomelandSecurity, Boston,

Curriculum Vitae for GordonR. Thompson November 2005 Page 5 Massachusetts, 27-28 April 2005, sponsored by the US Department of Homeland Security. (A version of this paper has also been published as CRS Discussion Paper 2005-02, Center for Risk and Security, George Perkins Marsh Institute, Clark University, Worcester, Massachusetts.)

- "Potential Radioactive Releases from Commercial Reactors and Spent Fuel",

Proceedings of the conference, Working Together: R&D Partnershipsin Homeland Security, Boston, Massachusetts, 27-28 April 2005, sponsored by the US Department of Homeland Security. (A version of this paper has also been published as CRS Discussion Paper 2005-03, Center for Risk and Security, George Perkins Marsh Institute, Clark University, Worcester, Massachusetts.)

• Safety of the ProposedSouth African Pebble Bed Modular Reactor,a report for the Legal Resources Centre, Cape Town, South Africa, 12 January 2005.

- Decommissioningof ResearchReactors at Brookhaven NationalLaboratory:Status, Future Options andHazards,a report for STAR Foundation, East Hampton, New York, April 2004.

- "Psychosocial Healing and Post-Conflict Social reconstruction in the Former Yugoslavia" (with Paula Gutlove), Medicine, Conflict and Survival, Volume 20, Number 2, April-June 2004, pp 136-150.

• "Reducing the Hazards from Stored SpentPower-Reactor Fuel in the United States" (with Robert Alvarez, Jan Beyea, Klaus Janberg, Jungmin Kang, Ed Lyman, Allison Macfarlane and Frank N. von Hippel), Science and GlobalSecurity, Volume 11, 2003, pp 1-51.

- "Health, Human Security, and Social Reconstruction in Afghanistan" (with Paula Gutlove and Jacob Hale Russell), in John D. Montgomery and Dennis A. Rondinelli (eds), Beyond Reconstructionin Afghanistan, Palgrave Macmillan, 2004.

- PsychosocialHealing:A Guidefor Practitioners,basedon programsof the Medical Network for SocialReconstruction in the Former Yugoslavia (with Paula Gutlove), IRS S, Cambridge, Massachusetts and OMEGA Health Care Center, Graz, Austria, May 2003.

- A CallforAction to Protect the Nation Against Enemy Attack on Nuclear Power Plants andSpent Fuel, and a Supporting Document, Mothers for Peace, San Luis Obispo, California, April 2003 and May 2003.

• "Human Security: Expanding the Scope of Public Health" (with Paula Gutlove),

Medicine, Conflict andSurvival, Volume 19, 2003, pp 17-34.

- SocialReconstruction in Afghanistan through the Lens of Health and Human Security (with Paula Gutlove and Jacob Hale Russell), IRSS, Cambridge, Massachusetts, May 2003.

• Robust Storage ofSpent Nuclear Fuel:A Neglected Issue of HomelandSecurity, a report commissioned by Citizens Awareness Network, Shelburne Falls, Massachusetts, January 2003.

• MedicalNetworkfor Social Reconstructionin the Former Yugoslavia: A Survey of Participants'Views on the Network's Goals andAchievements, IRSS, Cambridge, Massachusetts, September 2001.

- The Potentialfor a Large,Atmospheric Release of Radioactive MaterialfromSpent Fuel Pools at the HarrisNuclearPower Plant: The Case of a PoolRelease Initiatedby a

Curriculum Vitaefor GordonR. Thompson November 2005 Page 6 Severe Reactor Accident, a report for Orange County, North Carolina, 20 November 2000.

- A Review of the Accident Risk Posedby the Pickering 'A'NuclearGeneratingStation, a report for the Standing Committee on Energy, Environment and Natural Resources, Canadian Senate, August 2000.

- High-Level Radioactive Liquid Waste at Sellafield: An UpdatedReview, a report for the UK Nuclear Free Local Authorities, June 2000.

- HazardPotentialof the La Hague Site: An InitialReview, a report for Greenpeace International, May 2000.

- A Strategyfor Conflict Management:IntegratedAction in Theory andPractice (with Paula Gutlove), IRSS, Cambridge, Massachusetts, March 1999.

- Risks andAlternative OptionsAssociated with Spent Fuel Storage at the Shearon HarrisNuclearPower Plant, a report for Orange County, North Carolina, February 1999.

- High Level Radioactive Liquid Waste at Sellafield: Risks, Alternative Options and Lessons for Policy,IRSS, Cambridge, Massachusetts, June 1998.

- "Science, democracy and safety: why public accountability matters", in F. Barker (ed),

Management of Radioactive Wastes: Issuesfor local authorities,Thomas Telford, London, 1998.

• "Conflict Management and the OSCE" (with Paula Gutlove), OSCE/ODIHRBulletin, Volume 5, Number 3, Fall 1997.

- Safety of the Storage ofLiquidHigh-Level Waste at Sellafield (with Peter Taylor),

Nuclear Free Local Authorities, UK, November 1996.

- Assembling Evidence on the Effectiveness of Preventive Actions, their Benefits, and their Costs: A Guidefor PreparationofEvidence, IRSS, Cambridge, Massachusetts, August 1996.

• War, Terrorism andNuclearPower Plants,Peace Research Centre, Australian National University, Canberra, October 1996.

- "The Potential for Cooperation by the OSCE and Non-Governmental Actors on Conflict Management" (with Paula Gutlove), Helsinki Monitor,Volume 6 (1995), Number 3.

• "Potential Characteristics of Severe Reactor Accidents at Nuclear Plants", "Monitoring and Modelling Atmospheric Dispersion of Radioactivity Following a Reactor Accident" (with Richard Sclove, Ulrike Fink and Peter Taylor), "Safety Status of Nuclear Reactors and Classification of Emergency Action Levels", and "The Use of Probabilistic Risk Assessment in Emergency Response Planning for Nuclear Power Plant Accidents" (with Robert Goble), in D. Golding, J. X. Kasperson and R. E. Kasperson (eds), Preparingfor Nuclear Power PlantAccidents, Westview Press, Boulder, Colorado, 1995.

- A DataManagerfor the Global EnvironmentFacility (with Robert Goble),

Environment Department, The World Bank, June 1994.

- PreventiveDiplomacy andNationalSecurity (with Paula Gutlove), Winston Foundation for World Peace, Washington, DC, May 1994.

• OpportunitiesforInternationalControl of Weapons- Usable Fissile Material, International Physicians for the Prevention of Nuclear War, Cambridge, Massachusetts, January 1994.

• "Article III and IAEA Safeguards", in F. Barnaby and P. Ingram (eds), Strengthening the Non-ProliferationRegime, Oxford Research Group, Oxford, UK, December 1993.

Curriculum Vitae for Gordon R. Thompson November 2005 Page 7

• Risk Implicationsof PotentialNew NuclearPlants in Ontario (prepared with the help of eight consultants), a report for the Coalition of Environmental Groups, Toronto, submitted to the Ontario Environmental Assessment Board, November 1992 (3 volumes).

• Strengtheningthe InternationalAtomic EnergyAgency, IRSS, Cambridge, Massachusetts, September 1992.

- Design of an Information System on Technologies that can Limit Greenhouse Gas Emissions (with Robert Goble and F. Scott Bush), Center for Strategic and International Studies, Washington, DC, May 1992.

• ManagingNuclearAccidents: A Model Emergency Response Planfor Power Plants and Communities (with six other authors), Westview Press, Boulder, CO, 1992.

• "Let's X-out the K" (with Steven C. Sholly), Bulletin of the Atomic Scientists, March 1992, pp 14-15.

0 "A Worldwide Programme for Controlling Fissile Material", and "A Global Strategy for Nuclear Arms Control", in F. Barnaby (ed), Plutonium and Security, Macmillan Press, UK, 1992.

• No Restartfor K Reactor (with Steven C. Sholly), IRSS, Cambridge, Massachusetts, October 1991.

- Regulatory Response to the Potentialfor ReactorAccidents: The Example of Boiling-Water Reactors, IRSS, Cambridge, Massachusetts, February 1991.

• Peace by Piece:New Optionsfor InternationalArmsControlandDisarmament,IRSS, Cambridge, Massachusetts, January 1991.

• Developing PracticalMeasures to Prevent Climate Disruption (with Robert Goble),

CENTED Research Report No. 6, Clark University, Worcester, Massachusetts, August 1990.

" "Treaty a Useful Relic", Bulletin ofthe Atomic Scientists, July/August 1990, pp 32-33.

• "Practical Steps for the 1990s", in Sadruddin Aga Khan (ed), Non-Proliferationin a DisarmingWorld, Proceedings of the Groupe de Bellerive's 6th International Colloquium, Bellerive Foundation, Geneva, Switzerland, 1990.

- A GlobalApproach to ControllingNuclear Weapons, IRSS, Cambridge, Massachusetts, October 1989.

- IAEA Safety Targets andProbabilisticRiskAssessment (with three other authors),

Greenpeace International, Amsterdam, August 1989.

- New Directionsfor NATO (with Paul Walker and Pam Solo), published jointly by IRSS and the Institute for Peace and International Security (both of Cambridge, Massachusetts), December 1988.

- "Verifying a Halt to the Nuclear Arms Race", in F. Bamaby (ed), A Handbook of Verification Procedures,Macmillan Press, UK, 1990.

• "Verification of a Cutoff in the Production of Fissile Material", in F.Bamaby (ed), A Handbook of Verification Procedures,Macmillan Press, UK, 1990.

• "Severe Accident Potential of CANDU Reactors," Consultant's Report in The Safety of Ontario'sNuclear Power Reactors, Ontario Nuclear Safety Review, Toronto, February 1988.

"Nuclear-FreeZones (edited with David Pitt), Croom Helm Ltd, Beckenham, UK, 1987.

• Risk Assessment Review For the SocioeconomicimpactAssessment ofthe Proposed High-Level Nuclear Waste Repository at HanfordSite, Washington (edited; written with

Curriculum Vitae for Gordon R. Thompson November 2005 Page 8 five other authors), prepared for the Washington Department of Ecology, December 1987.

- The NuclearFreeze Revisited (with Andrew Haines), Nuclear Freeze and Arms Control Research Project, Bristol, UK, November 1986. Variants of the same paper have appeared as Working Paper No. 18, Peace Research Centre, Australian National University, Canberra, February 1987, and inADIUReport, University of Sussex, Brighton, UK, Jan/Feb 1987, pp 6-9.

• InternationalNuclear Reactor HazardStudy (with fifteen other authors), Greenpeace, Hamburg, Federal Republic of Germany (2 volumes), September 1986.

• "What happened at Reactor Four" (the Chernobyl reactor accident), Bulletin of the Atomic Scientists,August/September 1986, pp 26-3 1.

• The Source Term Debate: A Report by the Union of ConcernedScientists (with Steven C. Sholly), Union of Concerned Scientists, Cambridge, Massachusetts, January 1986.

- "Checks on the spread" (a review of three books on nuclear proliferation), Nature, 14 November 1985, pp 127-128.

- Editing of Perspectiveson Proliferation,August 1985, published by the Proliferation Reform Project, IRSS.

- "A Turning Point for the NPT ?", ADIUReport, University of Sussex, Brighton, UK, Nov/Dee 1984, pp 1-4.

- "Energy Economics", in J. Dennis (ed), The NuclearAlmanac, Addison-Wesley, Reading, Massachusetts, 1984.

• "The Genesis of Nuclear Power", in J. Tirman (ed), The Militarizationof High Technology, Ballinger, Cambridge, Massachusetts, 1984.

- A Second Chance:New Hampshire'sElectricityFuture as a Modelfor the Nation (with Linzee Weld), Union of Concerned Scientists, Cambridge, Massachusetts, 1983.

• Safety and Waste ManagementImplicationsof the Sizewell PWR (prepared with the help of six consultants), a report to the Town & Country Planning Association, London, UK, 1983.

- Utility-Scale ElectricalStorage in the USA: The ProspectsofPumped Hydro, CompressedAir,and Batteries,Princeton University report PU/CEES #120, 1981.

- The Prospectsfor Wind and Wave Power in North America, Princeton University report PU/CEES # 117, 198 1.

• HydroelectricPower in the USA: Evolving to Meet New Needs, Princeton University report PU/CEES # 115, 1981.

- Editing and part authorship of "Potential Accidents & Their Effects", Chapter III of Report of the Gorleben InternationalReview, published in German by the Government of Lower Saxony, FRG, 1979; Chapter III published in English by the Political Ecology Research Group, Oxford, UK.

-A Study of the Consequences to the Public of a Severe Accident at a CommercialFBR locatedat Kalkar, West Germany, Political Ecology Research Group, 1978.

Expert presentations and testimony (selected)

• Presentation, "Are Nuclear Installations Terrorist Targets?", at the conference, Nuclear Energy: Does it Have a Future?,Drogheda, County Louth, Ireland, 10-11 March 2005.

Curriculum Vitaefor Gordon R. Thompson November 2005 Page 9 Presentation at the session, "UN Security Council Resolution 1244 and Final Status for Kosovo", at the conference, Lessons Learnedfrom the Balkan Conflicts, Boston College, Chestnut Hill, Massachusetts, 16-17 October 2004.

- California Public Utilities Commission, 2004: testimony regarding the nature and cost of potential measures for enhanced defense of the Diablo Canyon nuclear power plant.

- European Parliament, 2003: invited presentation to EP members regarding safety and security issues at the Sellafield nuclear site in the UK, and broader implications.

- US Congress, 2002 and 2003: invited presentations at member-sponsored staff briefings on vulnerabilities of nuclear-power facilities to attack and options for improved defenses.

- Numerous public forums in the USA, 2001-2005: invited presentations to public officials and general audiences regarding vulnerabilities of nuclear-power facilities to attack and options for improved defenses.

- UK Consensus Conference on Radioactive Waste Management, 1999: invited testimony on information and decision-making.

- Joint Committee on Public Enterprise and Transport, Irish Parliament, 1999: invited testimony on nuclear fuel reprocessing and international security.

- UK and Irish Parliaments, 1998: invited presentations to members on risks and alternative options associated with nuclear fuel reprocessing in the UK.

• Center for Russian Environmental Policy, Moscow, 1996: invited presentation at a forum in parallel with the G-7 Nuclear Safety Summit.

• Lacey Township Zoning Board, New Jersey, 1995: testimony regarding radioactive waste management.

- Ontario Court of Justice, Toronto, Ontario, 1993: testimony regarding Canada's Nuclear Liability Act.

- Oxford Research Group, seminar on "The Plutonium Legacy", Rhodes House, Oxford, UK, 1993: invited presentation on nuclear safeguards.

• Defense Nuclear Facilities Safety Board, Washington, DC, 1991: testimony regarding the proposed restart of K-reactor, Savannah River Site.

- Conference to consider amending the Partial Test Ban Treaty, United Nations, New York, 1991: presentation on a global approach to arms control and disarmament.

- US Department of Energy, hearing on draft EIS for new production reactor capacity, Columbia, South Carolina, 1991: testimony on tritium need and implications of tritium production options.

- Society for Risk Analysis, 1990 annual meeting, New Orleans, special session on nuclear emergency planning: presentation on real-time techniques for anticipating emergencies.

• Parliamentarians' Global Action, 11th Annual Parliamentary Forum, United Nations, Geneva, 1990: invited presentation on the potential for multilateral nuclear arms control.

- Advisory Committee on Nuclear Facility Safety, Washington, DC, 1989: testimony on public access to information and on government accountability.

• Peace Research Centre, Australian National University, seminar on "Australia and the Fourth NPT Review Conference", Canberra, 1989: invited presentation regarding a universal nuclear weapons non-proliferation regime.

Curricuuhm Vitae for GordonR. Thompson November 2005 Page 10 Carnegie Endowment for International Peace, Conference on "Nuclear Non-Proliferation and the Role of Private Organizations", Washington, DC, 1989: invited presentation on options for reform of the non-proliferation regime.

- US Department of Energy, EIS scoping hearing, Columbia, South Carolina, 1988:

testimony on appropriate scope of an EIS for new production reactor capacity.

- International Physicians for the Prevention of Nuclear War, 6th and 7th Annual Congresses, Koln, FRG, 1986 and Moscow, USSR, 1987: invited presentations on relationships between nuclear power and the threat of nuclear war.

- County Council, Richland County, South Carolina, 1987: testimony on implications of severe reactor accidents at the Savannah River Plant.

- Maine Land Use Regulation Commission, 1985: testimony on cogeneration potential at facilities of Great Northern Paper Company.

- Interfaith Hearings on Nuclear Issues, Toronto, Ontario, 1984: invited presentations on options for Canada's nuclear trade and Canada's involvement in nuclear arms control.

- Sizewell Public Inquiry, UK, 1984: testimony on safety and radioactive waste implications of the proposed Sizewell nuclear power plant.

- New Hampshire Public Utilities Commission, 1983: testimony on electricity demand and supply options for New Hampshire.

• Atomic Safety & Licensing Board, US Nuclear Regulatory Commission, 1983:

testimony on use of filtered venting at the Indian Point nuclear power plant.

• US National Advisory Committee on Oceans and Atmosphere, 1982: testimony on implications of ocean disposal of radioactive waste.

• Environmental & Energy Study Conference, US Congress, 1982: invited presentation on implications of radioactive waste management.

Miscellaneous

• Married, two children.

• Extensive experience in public speaking and interviews by mass media.

• Author of numerous essays and letters in newspapers and magazines.

Contact information Institute for Resource and Security Studies 27 Ellsworth Avenue, Cambridge, Massachusetts 02139, USA Phone: 617-491-5177 Fax: 617-491-6904 E-mail: gthompson@irss-usa.org

• al.

INSTITUTE FOR RESOURCE AND SECURITY STUDIES 27 Ellsworth Avenue, Cambridge, Massachusetts 02139, USA Phone: 617-491-5177 Fax: 617-491-6904 Email: info@irss-usa.org Risks and Risk-Reducing Options Associated with Pool Storage of Spent Nuclear Fuel at the Pilgrim and Vermont Yankee Nuclear Power Plants by Gordon R. Thompson 25 May 2006 A report for Office of the Attomey General Commonwealth of Massachusetts Abstract This report addresses some of the risks associated with the future operation of the Pilgrim and Vermont Yankee nuclear power plants. The risks that are addressed here arise from the storage of spent nuclear fuel in a water-filled pool adjacent to the reactor at each plant. Both pools are now equipped with high-density, closed-form storage racks.

Options are available to reduce spent-fuel-pool risks. The option that would achieve the largest risk reduction at each plant, during operation within a license extension period, would be to re-equip the pool with low-density, open-frame storage racks. That option would return the plant to its original design configuration. This report describes risks and risk-reducing options, and relevant analysis that is required from the licensee and the Nuclear Regulatory Commission in the context of license extension applications for the Pilgrim and Vermont Yankee plants.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page2 About the Institute for Resource and Security Studies The Institute for Resource and Security Studies (IRSS) is an independent, nonprofit, Massachusetts corporation, founded in 1984. Its objective is to promote sustainable use of natural resources and global human security. In pursuit of this mission, IRSS conducts technical and policy analysis, public education, and field programs. IRSS projects always reflect a concern for practical solutions to resource and security problems.

About the Author Gordon R. Thompson is the executive director of IRSS and a research professor at Clark University, Worcester, Massachusetts. He studied and practiced engineering in Australia, and received a doctorate in applied mathematics from Oxford University in 1973, for analyses of plasma undergoing thermonuclear fusion. Dr. Thompson has been based in the USA since 1979. His professional interests encompass a range of technical and policy issues related to international security and protection of natural resources. He has conducted numerous studies on the environmental and security impacts of nuclear facilities and options for reducing these impacts.

Dr. Thompson independently identified the potential for a spent-fuel-pool fire, and articulated alternative options for lower-risk storage of spent fuel, during his work for the German state government of Lower Saxony in 1978-1979. His findings were accepted by that government after a public hearing. Since that time, Thompson has conducted several other studies on spent-fuel-storage risk, alone and with colleagues. Findings of these studies have been confirmed by a 2005 report by the National Academy of Sciences, prepared at the request of the US Congress.

Acknowledgements This report was prepared by IRSS for the Office of the Attorney General, Commonwealth of Massachusetts. Gordon R. Thompson is solely responsible for the content of the report.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page3 Contents

1. Introduction

2. Recognition of the Spent-Fuel Hazard

3. Characteristics of the Pilgrim and Vermont Yankee Plants and their Spent Fuel

4. Trends in Management of Spent Fuel

5. Technical Understanding of Spent-Fuel-Pool Fires

6. Initiation of a Pool Fire by an Accident Not Involving Malice

7. Initiation of a Pool Fire by Malicious Action

8. Options to Reduce the Risks of Pool Fires

9. An Integrated View of Risks and Risk-Reducing Options

10. Analysis Required From Entergy and the Nuclear Regulatory Commission

11. Conclusions

12. Bibliography Tables (See next page)

Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page4 List of Tables (Tables are located at the end of the report.)

Table 3-1: Selected Characteristics of the Pilgrim and Vermont Yankee Plants Table 3-2: Selected Characteristics of the Spent-Fuel Pools at the Pilgrim and Vermont Yankee Plants Table 3-3: Estimation of Cesium-137 Inventory in a Spent-Fuel Assembly and the Reactor Core, for the Pilgrim and Vermont Yankee Plants Table 3-4: Estimated Future Inventory and Selected Characteristics of Spent Fuel in Pools at the Pilgrim and Vermont Yankee Plants Table 3-5: Illustrative Inventories of Cesium-137 Table 4-1: Estimated Duration of Phases of Implementation of the Yucca Mountain Repository Table 4-2: Potential Emplacement Area of the Yucca Mountain Repository for Differing Spent-Fuel Inventories and Operating Modes Table 4-3: Estimated Number of Radioactive-Waste Shipments to the Yucca Mountain Site Table 4-4: Characteristics of BWR-Spent-Fuel Storage Canisters or Disposal Packages Proposed for Use at the Monticello or Skull Valley ISFSIs, or at Yucca Mountain Table 5-1: Estimated Source Term for Atmospheric Release from Spent-Fuel-Pool Fire at the Pilgrim or Vermont Yankee Plant Table 6-1: Licensee Estimates of Core Damage Frequency and Radioactive Release Frequency, Pilgrim Plant Table 6-2: Licensee Estimates of Core Damage Frequency and Radioactive Release Frequency, Vermont Yankee Plant Table 6-3: Categories of Release to Atmosphere by Core-Damage Accidents at Pilgrim and Vermont Yankee Nuclear Plants Table 7-1: Potential Sabotage Events at a Spent-Fuel-Storage Pool, as Postulated in the NRC's August 1979 GEIS on Handling and Storage of Spent LWR Fuel

Risks ofpool storageof spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 5 Table 7-2: Potential Modes and Instruments of Attack on a Nuclear Power Plant Table 8-1: Selected Options to Reduce Risks of Spent-Fuel-Pool Fires at the Pilgrim and Vermont Yankee Plants Table 8-2: Selected Approaches to Protecting US Critical Infrastructure From Attack by Sub-National Groups, and Some of the Strengths and Weaknesses of these Approaches Table 8-3: Estimation of Cost to Offload Spent Fuel from Pools at the Pilgrim and Vermont Yankee Plants After 5 Years of Decay Table 9-1: Provisional Estimate of the Probability of a Spent-Fuel-Pool Fire at the Pilgrim or Vermont Yankee Plant Table 9-2: Present Value of Cumulative (20-year) Economic Risk of a Potential Release of Radioactive Material

Risks ofpool storage ofspentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 6

1. Introduction Applications have been submitted for 20-year extensions of the operating licenses of the Pilgrim and Vermont Yankee nuclear power plants. These plants began operating in 1972, and their current operating licenses expire in 2012. The designs of the two plants are broadly similar, and both are operated by Entergy Nuclear Operations Inc. (Entergy).

Each plant features a boiling-water reactor (BWR) with a Mark I containment. The US Nuclear Regulatory Commission (NRC) has announced that interested persons can petition to intervene in the license extension proceedings for these plants. In that context, the Office of the Attorney General, Commonwealth of Massachusetts, has requested the preparation of this report.

This report addresses a particular set of risks associated with the future operation of the Pilgrim and Vermont Yankee plants. These risks arise from the storage of spent nuclear fuel in water-filled pools. Each plant's nuclear reactor periodically discharges fuel that is "spent" in the sense that the fuel is no longer suitable for power generation. The spent fuel contains a large amount of radioactive material, and is stored in a water-filled pool adjacent to the reactor. In this report, the word "risk" applies to the potential for a release of radioactive material from nuclear fuel to the atmosphere. Other risks arise from the operation of nuclear power plants, but are not addressed here. The concept of risk encompasses both the consequences and probability of an event. However, risk is not simply the arithmetic product of consequence and probability numbers, as is sometimes assumed.

Although this report focuses on the risks arising from pool storage of spent fuel, the report necessarily considers some aspects of the risks arising from operation of the reactor at each plant. Such consideration is necessary because the pool and the reactor are in close physical proximity within the same building, and some of their essential support systems are shared. Thus, an incident involving a release of radioactive material from the pool could be initiated or exacerbated by an incident at the reactor, or vice versa, or parallel incidents at the pool and the reactor could have a common cause.

Scope of this analysis This report does not purport to provide a comprehensive assessment of the risks arising from pool storage of spent fuel at the Pilgrim and Vermont Yankee plants. As discussed in Section 10, below, preparation of such an assessment is a duty of Entergy and the NRC. Neither party has performed this duty. In the absence of a comprehensive assessment, this report provides illustrative analysis of selected issues. Assumptions of the analysis are stated, and the author would be pleased to engage in open technical debate regarding his analysis. A companion report, prepared independently by Dr. Jan Beyea, examines the offsite consequences of releases of radioactive material. Findings in that report are consistent with scientific knowledge and experience in the field of

Risks ofpool storage ofspentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 7 radiological consequence assessment. Questions about the analysis in that report should be directed to Dr. Beyea.

Five major purposes are pursued in this report. The focus throughout is on the Pilgrim and Vermont Yankee plants and their license extension applications, but much of the report's discussion has wider application. First, the potential for a release of radioactive material from a spent-fuel pool is described. Second, options for reducing the probability and/or consequences of such a release are described. These descriptions provide a general picture of the risks and risk-reducing options associated with pool storage of spent fuel. Third, an integrated view of these risks and risk-reducing options is provided.

Fourth, the state of knowledge about these risks and risk-reducing options is reviewed.

Fifth, the technical analysis required from Entergy and the NRC to improve this state of knowledge is described.

Two classes of event could lead to a release of radioactive material from a spent-fuel pool. One class of events, typically described as "accidents", includes human error, equipment failure and/or natural forces such as earthquakes. A second class encompasses deliberate, malicious acts. Some events, which involve harmful acts by insane but cognitively functioning persons, fall into both classes. This report considers the full range of initiating events, including human error, equipment failure, natural forces, malice, and/or insanity.

Protectionofsensitive information Any responsible analyst who discusses potential acts of malice at nuclear power plants is careful about making statements in public settings. The author of this report exercises such care. The author has no access to classified information, and this report contains no such information. However, a higher standard of discretion is necessary. An analyst should not publish detailed information that will assist potential attackers, even if this information is publicly available from other sources. On the other hand, if a plant's design and operation leave the plant vulnerable to attack, and the vulnerability is not being addressed appropriately, then a responsible analyst is obliged to publicly describe the vulnerability in general terms.

This report exemplifies the balance of responsibility described in the preceding paragraph. Vulnerabilities of the Pilgrim and Vermont Yankee plants are described here in general terms. Detailed information relating to those vulnerabilities .is withheld here, although that information has been published elsewhere or could be re-created by many persons with technical education and/or military experience. For example, this report does not provide cross-section drawings of the Pilgrim and Vermont Yankee plants, although such drawings have been published for many years and are archived around the world. NRC license proceedings provide potential forums at which sensitive information can be discussed without concern about disclosure to potential attackers. Rules and practices are available so that the parties to a license proceeding can discuss sensitive information in a protected setting.

Risks ofpool storage ofspentfitel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 8 Structure of this report The remainder of this report has eleven sections. Section 2 outlines the hazard posed by storage of spent fuel in a high-density configuration in pools at nuclear power plants, and describes the history of attention to this issue. The hazard arises from the potential for a self-ignited fire in a spent-fuel pool if water is lost from the pool. Technical aspects of this hazard are discussed in greater detail in subsequent sections of the report.

Characteristics of the Pilgrim and Vermont Yankee plants and their spent fuel are described in Section 3. National trends in the management of spent nuclear fuel are described in Section 4, providing evidence that spent fuel is likely to remain at the Pilgrim and Vermont Yankee sites for at least several decades, and potentially for more than a century. The risks of spent-fuel storage will continue to accumulate over that period.

Section 5 reviews the state of technical knowledge about potential spent-fuel-pool fires.

Scenarios for such a fire at the Pilgrim or Vermont Yankee plants are discussed in the two following sections. Section 6 discusses scenarios initiated by accidents not involving malice, while Section 7 discusses scenarios initiated by malicious action. Options to reduce the risks of spent-fuel-pool fires at the Pilgrim and Vermont Yankee plants are described in Section 8. An integrated view of risks and risk-reducing options at these plants is set forth in Section 9.

In Section 5 and elsewhere, this report discusses the state of technical knowledge about risks and risk-reducing options associated with spent-fuel pools. There are substantial deficiencies in present knowledge. Section 10 describes the technical analysis required from Entergy and the NRC to correct these deficiencies in the context of license extension applications for Pilgrim and Vermont Yankee. Conclusions are set forth in Section 11, and a bibliography is provided in Section 12. All documents cited in the text of this report are listed in the bibliography.

2. Recognition of the Spent-Fuel Hazard From the earliest years of the nuclear-technology era, analysis and experience have shown that a nuclear reactor can undergo an accident in which the reactor's fuel is damaged. This damage can lead to a release of radioactive material within the reactor and, potentially, from the reactor to the external environment. An early illustration of this accident potential occurred in the UK in 1957, when an air-cooled reactor at Windscale caught fire and released radioactive material to the atmosphere. At that time, spent fuel was not perceived as a significant hazard.

When the Pilgrim and Vermont Yankee plants began operating in 1972, there was limited technical understanding of the potential for severe accidents at commercial reactors. In this context, "severe" means that the reactor core is severely damaged, which typically involves melting of some fraction of the core materials. The environmental impact

Risks ofpool storage ofspentfiel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page9 statements (EISs) related to the operation of Pilgrim and Vermont Yankee did not consider severe reactor accidents.' Knowledge about the potential for such accidents was improved by completion of the Reactor Safety Study (WASH-1400) in 1975.2 More knowledge has accumulated from analysis and experience since that time.3 Until 1979 it was widely assumed that stored spent fuel did not pose risks comparable to those associated with reactors. This assumption arose because a spent fuel assembly does not contain short-lived radioactivity, and therefore produces less radioactive decay heat than does a similar fuel assembly in an operating reactor. However, that factor was counteracted by the introduction of high-density, closed-form storage racks into spent-fuel pools, beginning in the 1970s. Initially, pools were designed so that each held only a small inventory of spent fuel, with the expectation that spent fuel would be stored briefly and then taken away for reprocessing. Low-density, open-frame storage racks were used.

Cooling fluid can circulate freely through such a rack. When reprocessing was abandoned in the United States, spent fuel began to accumulate in the pools. Excess spent fuel could have been offloaded to other storage facilities, allowing continued use of low-density racks. Instead, as a cost-saving measure, high-density racks were introduced, allowing much larger amounts of spent fuel to be stored in the pools.

The potentialfor a poolfire Unfortunately, the closed-form configuration of the high-density racks would create a major problem if water were lost from a spent-fuel pool. The flow of air through the racks would be highly constrained, and would be almost completely cut off if residual water or debris were present in the base of the pool. As a result, removal of radioactive decay heat would be ineffective. Over a broad range of water-loss scenarios, the temperature of the zirconium fuel cladding would rise to the point (approximately 1,000 degrees C) where a self-sustaining, exothermic reaction of zirconium with air or steam would begin. Fuel discharged from the reactor for I month could ignite in less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, and fuel discharged for 3 months could ignite in about 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.4 Once initiated, the fire would spread to adjacent fuel assemblies, and could ultimately involve all fuel in the pool. A large, atmospheric release of radioactive material would occur. For simplicity, this potential disaster can be described as a "pool fire".

Water could be lost from a spent-fuel pool through leakage, boiling, siphoning, pumping, displacement by objects falling into the pool, or overturning of the pool. These modes of water loss could arise from events, alone or in combination, that include: (i) acts of malice by persons within or outside the plant boundary; (ii) an accidental aircraft impact; (iii) an earthquake; (iv) dropping of a fuel cask; (v) accidental fires or explosions; and (vi) a severe accident at an adjacent reactor that, through the spread of radioactive 1AEC, 1972a; AEC, 1972b.

2NRC, 1975.

3 Relevant experience includes the Three Mile Island reactor accident of 1979 and the Chernobyl reactor accident of 1986.

4This sentence assumes adiabatic conditions.

Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 10 material and other influences, precludes the ongoing provision of cooling and/or water makeup to the pool.

These events have differing probabilities of occurrence. None of them is an everyday event. Nevertheless, they are similar to events that are now routinely considered in planning and policy decisions related to commercial nuclear reactors. To date, however, such events have not been given the same attention in the context of spent-fuel pools.

Some people have found it counter-intuitive that spent fuel, given its comparatively low decay heat and its storage under water, could pose a fire hazard. This perception has slowed recognition of the hazard. In this context, a simple analogy may be helpful. We all understand that a wooden house can stand safely for many years but be turned into an inferno by a match applied in an appropriate location. A spent-fuel pool equipped with high-density racks is roughly analogous, but in this case ignition would be accomplished by draining water from the pool. In both cases, a triggering event would unleash a large amount of latent chemical energy.

The sequence ofstudies relatedto poolfires Two studies completed in March 1979 independently identified the potential for a fire in a drained spent-fuel pool equipped with high-density racks. One study was by members of a scientific panel assembled by the German state government of Lower Saxony to review a proposal for a nuclear fuel cycle center at Gorleben.s After a public hearing, the Lower Saxony government ruled in May 1979, as part of a broader decision,'that high-density pool storage of spent fuel would not be acceptable at Gorleben. The second study was done by Sandia Laboratories for the NRC.6 In light of knowledge that has accumulated since 1979, the Sandia report generally stands up well, provided that one reads the report in its entirety. However, the report's introduction contains an erroneous statement that complete drainage of the pool is the most severe situation. The body of the report clearly shows that partial drainage can be a more severe case, as was recognized in the Gorleben context. Unfortunately, the NRC continued, until October 2000, to employ the erroneous assumption that complete drainage is the most severe case.

The NRC has published various documents that discuss aspects of the potential for a spent-fuel-pool fire. Several of these documents are discussed in Section 5, below. Only three of the various documents are products of processes that provided an opportunity for formally structured public comment and, potentially, for in-depth analysis of risks and alternatives. One such document is the August 1979 Generic Environmental Impact Statement (GELS) on handling and storage of spent fuel (NUREG-0575). 7 The second document is the May 1996 GEIS on license renewal (NUREG-1437). 8 These two documents purported to provide systematic analysis of the risks and relative costs and 5Thompson et al, 1979.

6 Benjamin et al, 1979.

7NRC, 1979.

'NRC, 1996.

Risks ofpool storage ofspentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 11 benefits of alternative options. The third document is the NRC's September 1990 review (55 FR 38474) of its Waste Confidence Decision. 9 That document did not purport to provide an analysis of risks and alternatives.

NUREG-0575 addresses the potential for a spent-fuel-pool 0 fire in a single sentence that cites the 1979 Sandia report. The sentence reads:1 Assuming that the spent fuel stored at an independent spent fuel storage installation is at least one year old, calculations have been performed to show that loss of water should not result in fuel failure due to high temperatures if proper rack design is employed.

Although this sentence refers to pool storage of spent fuel at an independent spent fuel storage installation, NUREG-0575 regards at-reactor pool storage as having the same properties. This sentence misrepresents the findings of the Sandia report. The sentence does not define "proper rack design". It does not disclose Sandia's findings that high-density racks promote overheating of exposed fuel, and that overheating can cause fuel to self-ignite and burn. The NRC has never corrected this deficiency in NUREG-0575.

NUREG-1437 also addresses the potential for a spent-fuel-pool fire in a single sentence, which in this instance states:"1 NRC has also found that, even, under the worst probable cause of a loss of spent-fuel pool coolant (a severe seismic-generated accident causing a catastrophic failure of the pool), the likelihood of a fuel-cladding fire is highly remote (55 FR 38474).

The parenthetic citation is to the NRC's September 1990 review of its Waste Confidence Decision. Thus, NUREG-1437's examination of pool fires is totally dependent on the September 1990 review. In turn, that review bases its opinion about pool fires on the following four NRC documents:12 (i) NUREG/CR-4982;' (ii) NUREG/CR-5176;'4 (iii)

NUREG-1353;1 5 and (iv) NUREG/CR-528 1.16 These documents are discussed in Section 5, below. That discussion reveals substantial deficiencies in the documents' analysis of the potential for a pool fire.

Thus, neither of the two GEISs (NUREG-0575 and NUREG-1437), nor the September 1990 review of the Waste Confidence Decision, provides a technically defensible 9

NRC, 1990a.

1oNRC, 1979, page 4-21.

" NRC, 1996, pp 6-72 to 6-75.

12NRC, 1990a, page 38481.

13Sailor et al, 1987.

" Prassinos et a], 1989.

15Throm, 1989.

16 Jo et a], 1989.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 12 examination of spent-fuel-pool fires and the associated risks and alternatives. The statements in each document regarding pool fires are inconsistent with the findings of subsequent, more credible studies discussed below.

The most recent published NRC technical study on the potential for a pool fire is an NRC Staff study, originally released in October 2000 but formally published in February 2001, that addresses the risk of a pool fire at a nuclear power plant undergoing decommissioning. 7 This author submitted comments on the study to the NRC Commissioners in February 2001.18 The study was in several respects an improvement on previous NRC documents that addressed pool fires. It reversed the NRC's longstanding, erroneous position that total, instantaneous drainage of a pool is the most severe case of drainage. However, it did not consider acts of malice. Nor did it add significantly to the weak base of technical knowledge regarding the propagation of a fire from one fuel assembly to another. Its focus was on a plant undergoing decommissioning. Therefore, it did not address potential interactions between pools and operating reactors, such as the interactions discussed in Section 6, below.

In 2003, eight authors, including the present author, published a paper on the risks of spent-fuel-pool fires and the options for reducing these risks.19 That paper aroused vigorous comment, and its findings were disputed by NRC officials and others. Critical comment was also directed to a related report by this author.20 In an effort to resolve this controversy, the US Congress requested the National Academy of Sciences (NAS) to conduct a study on the safety and security of spent-fuel storage. The NAS submitted a classified report to Congress in July 2004, and released an unclassified version in April 2005.21 Press reports described considerable tension between the NAS22 and the NRC regarding the inclusion of material in the unclassified NAS report.

Since September 2001, the NRC has not published any document that contains technical analysis related to the potential for a pool fire. The NRC claims that it is conducting further analysis in a classified setting. The scope of information treated as secret by the NRC is questionable. Much of the relevant analysis would address issues such as heat transfer and fire propagation. Calculations and experiments on such subjects should be performed and reviewed in the public domain. Classification is appropriate for other information, such as specific points of vulnerability of a spent-fuel pool to attack.

3. Characteristics of the Pilgrim and Vermont Yankee Plants and their Spent Fuel Basic data about the Pilgrim and Vermont Yankee plants are set forth in Table 3-1. Data and estimates about storage of spent fuel at these plants are set forth in Tables 3-2

.17 Collins and Hubbard, 2001 1 Thompson, 2001 a.

19Alvarez et al, 2003.

20 Thompson, 2003.

21NAS, 2006.

2 Wald, 2005.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 13 through 3-5. In regard to the latter tables, publicly available information is incomplete and inconsistent. Therefore, assumptions are made at various points in the tables, as is readily evident. In addition, the estimates set forth in Tables 3-3 through 3-5 involve a number of simplifying assumptions, which are also evident from the tables.

The scope and accuracy of Tables 3-1 through 3-5 could be improved using information that is held by Entergy and the NRC. Given this information, a more sophisticated analysis could be conducted to estimate the inventories and other characteristics of the Pilgrim and Vermont Yankee spent-fuel pools during the requested period of license extension. These improvements would not alter the basic findings of this report.

At the Pilgrim plant, the present configuration of the storage racks in the spent-fuel pool reflects a license amendment approved by the NRC in 1994. A report submitted by the licensee in support of that license amendment states that the existing racks in the pool and the proposed new racks had a center-to-center distance of about 6.3 inches in both directions. The new racks would, when fully installed, fill the pool tightly, wall-to-wall.2 3 Equivalent detail is not available regarding the present configuration of racks in the Vermont Yankee pool. However, from the data provided in Table 3-2 regarding the capacities, inventories and dimensions of both pools, it24is evident that the Vermont Yankee pool configuration is similar to that at Pilgrim.

Entergy has announced its intention to establish an independent spent fuel storage installation (ISFSI) at the Vermont Yankee site, and for this purpose has requested a Certificate of Public Good from the Vermont Public Service Board. The ISFSI would store fuel in dry-storage modules. Entergy has described its planned schedule for transferring spent fuel from the pool to the ISFSI. 25 From this schedule, it is evident that Entergy plans to use the spent-fuel pool at nearly its full capacity, storing the overflow from that capacity in the ISFSI.

Extension of the Pilgrim operating license would imply the establishment of an ISFSI at the Pilgrim site. Entergy has not yet announced a plan to establish such an ISFSI. Given the continuing accumulation of spent fuel in the Pilgrim pool, and the time required to establish an ISFSI, it can reasonably be presumed that Entergy plans to use the Pilgrim spent-fuel pool at nearly its full capacity, storing the overflow from that capacity in a future ISFSI.

Inventories ofcesium-137 The radioactive isotope cesium-137 provides a useful indicator of the hazard potential of the Pilgrim and Vermont Yankee spent-fuel pools. This isotope, which has a half-life of 23Holtec, 1993.

24 Hoffman, 2005, states that the present Vermont Yankee racks have a center-to-center distance of 6.2 inches.

25 Hoffman, 2005.

Risks ofpool storageofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 14 30 years, is a volatile element that would be liberally released during a pool fire.26 Table 3-4 shows the estimated inventory of cesium-137 in the Pilgrim and Vermont Yankee spent-fuel pools during the period of license extension. This table shows that the pools will hold about 1.6 million TBq (Pilgrim) and 1.4 million TBq (Vermont Yankee) of cesium-137. For comparison, Tables 3-3 and 3-5 provide licensee estimates showing that the Pilgrim and Vermont Yankee reactor cores will hold 190,000 TBq and 179,000 TBq, respectively, of cesium-137. Thus, each pool will hold about 8 times as much cesium-137 as will be present in the adjacent reactor.

4. Trends in Management of Spent Fuel Risks arising from storage of spent fuel will accumulate over time. Thus, it is important to estimate the time period during which spent fuel will be stored at the Pilgrim or Vermont Yankee site, whether in a pool or an onsite ISFSI. In testimony before the Vermont Public Service Board, an Entergy witness has stated that the US Department of Energy (DOE) could begin accepting spent fuel from Vermont Yankee as27early as 2015, for emplacement in the proposed repository in Yucca Mountain, Nevada.

Some decision makers have advocated a revival of spent-fuel reprocessing as an alternative to placing intact spent fuel in a repository. Reprocessing was the national strategy for spent-fuel management when the Pilgrim and Vermont Yankee plants were built, but was abandoned in the 1970s. If reprocessing were to resume, it would provide an option for removal of spent fuel from reactor sites.

This author has testified before the Vermont Public Service Board regarding the prospects for the Yucca Mountain repository, reprocessing, and other options for removal of spent fuel from the Vermont Yankee site. He concluded that spent fuel is likely to remain at the site for at least several decades, and potentially for more than a century.28 The same arguments apply to the Pilgrim site. Here, selected arguments are summarized, to illustrate the factors that will hinder removal of spent fuel from each site.

Current national policy for long-term management of spent fuel is to establish a repository inside Yucca Mountain. Progress with this project has been slow, and many observers believe that it will be cancelled. Even if the repository does open, there will be a delay before fuel can be shipped to Yucca Mountain and emplaced in the repository.

Table 4-1 shows a schedule projection by DOE, indicating that the emplacement process could occupy five decades.

2 6 A study by the US Department of Energy (DOE, 1987) shows that cesium-137 accounts for most of the offsite radiation exposure that is attributable to the 1986 Chernobyl reactor accident, and for about half of the radiation exposure that is attributable to fallout from nuclear weapons tests in the atmosphere. Note that the particular mechanisms of the Chernobyl accident could not occur in the Pilgrim or Vermont Yankee pool.

27 Hoffman, 2005.

28 Thompson, 2006.

Risks ofpool storageof spentfiel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 15 The US fleet of commercial reactors will probably produce more than 80,000 MgU of spent fuel if each reactor operates to the end of its initial 40-year license period. If each reactor received a 20-year license extension, the fleet could eventually produce a total of about 120,000 MgU of spent fuel. Yet, the capacity of Yucca Mountain is limited by federal statute to 63,000 MgU of spent fuel. DOE has investigated the option of placing 105,000 MgU of spent fuel in Yucca Mountain, which assumes a statute amendment.

However, Table 4-2 shows that emplacement of 105,000 MgU of fuel could require an emplacement area of up to 3,800 acres if a lower-temperature operating mode is selected.

Licensing considerations are likely to favor the selection of a lower-temperature operating mode, and there may not be enough space in the mountain to allow a total emplacement area of 3,800 acres. Thus, the physical capacity of Yucca Mountain could be less than 105,000 MgU of fuel.

As Table 4-3 shows, operation of the Yucca Mountain repository would involve a large number of spent-fuel shipments. This potential traffic poses a security concern, because there is evidence that shipping casks are more vulnerable to attack by sub-national groups than DOE has previously assumed.2 9 Spent-fuel shipments could be comparatively attractive targets because they cannot be protected to the same extent as nuclear power plants.

A further impediment to shipping spent fuel to Yucca Mountain is that DOE has announced that it will receive fuel in standard canisters that are inserted, unopened, into waste packages prior to emplacement in the repository. Yet, as Table 4-4 shows, the concept of a standard canister is incompatible with the present configurations of dry-storage canisters and the proposed configurations of Yucca Mountain disposal packages.

There is no clear path to resolution of this problem.

5. Technical Understanding of Spent-Fuel-Pool Fires Section 2, above, introduces the concept of a pool fire and describes the history of analysis of pool-fire risks. There is a body of technical literature on these risks, containing documents of varying degrees of completeness and accuracy. Current opinions about the risks vary widely, but the differences of opinion may be more about the probabilities of pool-fire scenarios than about the physical characteristics of these scenarios. In turn, differing opinions about probabilities lead to differing support for risk-reducing options. This situation is captured in a comment by Allan Benjamin on a paper (Alvarez et al, 2003) by this author and seven colleagues. 30 Benjamin's comment is quoted in the unclassified NAS report as follows:31 29 The term "sub-national group" is used in security analysis to describe a human group that is larger and more capable than an isolated individual, but is not an arm of a national government. This distinction has strategic significance because deterrence, a potentially effective means of influencing a national government, may not influence a sub-national group.

30 Allan Benjamin was one of the authors of: Benjamin et al, 1979.

31 NAS, 2006, page 45.

Risks ofpool storage of spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 16 In a nutshell, [Alvarez et al] correctly identify a problem that needs to be addressed, but they do not adequately demonstrate that the proposed solution is cost-effective or that it is optimal.

The "proposed solution" to which Benjamin refers is the re-equipment of spent-fuel pools with low-density, open-frame racks, transferring excess spent fuel to onsite dry storage.

In fact, however, the [Alvarez et al] authors had not claimed to complete the level of analysis, especially site-specific analysis, that risk-reducing 32 options should receive in an Environmental Report or EIS. These authors stated:

Finally, all of our proposals require further detailed analysis and some would involve risk tradeoffs that also would have to be further analyzed. Ideally, these analyses could be embedded in an open process in which both analysts and policy makers can be held accountable.

The paper by Alvarez et al is consistent with current knowledge of pool-fire phenomena, including the findings set forth in the unclassified NAS report. The same cannot be said for all of the NRC documents that were cited in the NRC's September 1990 review of its Waste Confidence Decision. As discussed in Section 2, above, four NRC documents were cited to support that review's finding regarding the risks of pool fires. 33 In turn, the May 1996 GEIS on license renewal (NUREG-1437) relied on the September 1990 review for its position on the risks of pool fires. The four NRC documents are discussed in the following paragraphs.

NUREG/CR-4982 was prepared at Brookhaven National Laboratory to provide "an assessment of the likelihood and consequences of a severe accident in a spent fuel storage pool". 34 The postulated accident involved complete, instantaneous loss of water from the pool, thereby excluding important phenomena from consideration. The Brookhaven authors employed a simplistic model to examine propagation of a fire from one fuel assembly to another. That model neglected important phenomena including slumping and bum-through of racks, slumping of fuel assemblies, and the accumulation of a debris bed at the base of the pool. Each of these neglected phenomena would promote fire propagation. The study ignored the potential for interactions between a pool fire and a reactor accident. It did not consider acts of malice. Overall, this study did not approach the completeness and quality needed to support consideration of a pool fire in an EIS.

NUREG/CR-5176 was prepared at Lawrence Livermore National Laboratory. 35 It examined the potential for earthquake-induced failure of the spent-fuel pool and the pool's support systems at the Vermont Yankee and Robinson Unit 2 plants. It also considered the effect of dropping a spent-fuel shipping cask on a pool wall. Overall, this study appears to have been a competent exercise within its stated assumptions. With 2Alvarez et al, 2003, page 35.

33 NRC, 1990a, page 38481.

34 Sailor et al, 1987.

35 Prassinos et al, 1989.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 17 appropriate updating, NUREG/CR-5176 could contribute to the larger body of analysis that would be needed to support consideration of a pool fire in an EIS.

NUREG-1353 was prepared by a member of the NRC Staff to support resolution of NRC Generic Issue 82.36 It postulated a pool accident involving complete, instantaneous loss of water from the pool, thereby excluding important phenomena from consideration. It relied on the fire-propagation analysis of NUREG/CR-4982. As discussed above, that analysis is inadequate. In considering heat transfer from BWR fuel after water loss, NUREG-1353 assumed that a high-density rack configuration would involve a 5-inch open space between each row of fuel assemblies. That assumption is inappropriate and non-conservative. Modem, high-density BWR racks have a center-to-center distance of about 6 inches in both directions. Thus, NUREG-1353 under-estimated the potential for ignition of BWR fuel. Overall, NUREG-1353 did not approach the completeness and quality needed to support consideration of a pool fire in an EIS.

NUREG/CR-5281 was prepared at Brookhaven National Laboratory to evaluate options for reducing the risks of pool fires." It took NUREG/CR-4982 as its starting point, and therefore shared the deficiencies of that study.

Clearly, these four NRC documents do not provide an adequate technical basis for an EIS that addresses the risks of pool fires. The knowledge that they do provide could be supplemented from other documents, including the unclassified NAS report, the paper by Alvarez et al, and the NRC Staff study (NUREG-1738) on pool-fire risk at a plant undergoing decommissioning.38 However, this combined body of information would be inadequate to support the preparation of an EIS. For that purpose, a comprehensive, integrated study would be required, involving analysis and experiment. The depth of investigation would be similar to that involved in preparing the NRC's December 1990 study on the risks of reactor accidents (NUREG-1 150).31 A pool-fire "sourceterm" The incompleteness of the present knowledge base is evident when one needs a "source term" to estimate the radiological consequences of a pool fire. The concept of a source term encompasses the magnitude, timing and other characteristics of a release of radioactive material. Present knowledge does not allow theoretical or empirically-based prediction of the source term for a postulated pool-fire scenario. Instead, informed judgment must be used.

Table 5-1 provides two versions of a source term for a pool fire at Pilgrim or Vermont Yankee. Each version assumes that a high-density pool would be almost full of spent 36 Throm, 1989.

37 Jo et al, 1989.

3'Collins and Hubbard, 2001.

39 NRC, 1990b.

Risks ofpool storage of spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 18 fuel, which is the expected mode of operation of each plant during the period of license extension.

One version of the source term involves a release of 100 percent of the cesium-137 in a pool. That is an upper limit. In practice, the cesium-137 release fraction would be less than 100 percent, but there is no way to determine if the largest achievable release fraction would be 90 percent or 95 percent or some other number. In any event, this large source term implies that all or most of the zirconium in the pool would oxidize. Table 5-1 assumes that the oxidation occurs over a period of 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. The second version of the source term involves a release of 10 percent of the cesium-137 in the pool, with oxidation of 10 percent of the zirconium over a period of 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.

Given present knowledge, the approximately 100-percent release and the 10-percent release are equally probable for a typical pool fire. A prudent decision maker could, therefore, reasonably use the 100-percent release to assess risks and risk-reducing options.

6. Initiation of a Pool Fire by an Accident Not Involving Malice Section 2, above, provides a general description of the potential for a spent-fuel-pool fire.

Such a fire could be caused by a variety of events. Here, accidental events not involving malice are considered, with a focus on the Pilgrim and Vermont Yankee plants. Section 7, below, considers events that involve malicious action.

At Pilgrim or Vermont Yankee, non-malicious events at the plant that could lead to a pool fire include: (i) an accidental aircraft impact, with or without an accompanying fuel-air explosion or fire; (ii) an earthquake; (iii) dropping of a fuel transfer cask or shipping cask; (iv) a fire inside or outside the plant building; and (v) a severe accident at the adjacent reactor.

Given the major consequences of a pool fire, analysis should have been performed to examine pool-fire scenarios across a full range of initiating events. The NRC has devoted substantial attention and resources to the examination of reactor-core-melt scenarios, through studies such as NUREG-1 150.40 Neither the NRC nor the nuclear industry has conducted a comparable study of pool fires. In the absence of such a study, this report provides illustrative analysis.

40NRC, 1990b.

Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 19 A poolfire accompaniedby a reactoraccident As mentioned in Section 1, above, at Pilgrim and Vermont Yankee the pool and the reactor are in close physical proximity within the same building, and some of their essential support systems are shared. These plants are, therefore, comparatively likely to experience a pool fire that is accompanied by a reactor accident.

This combination of accidents is the focus of discussion here. The pool fire and the reactor accident might have a common cause. For example, a severe earthquake could cause leakage of water from the pool, while also damaging the reactor and its supporting systems to such an extent that a core-melt accident occurs. In some scenarios, the high radiation field produced by a pool fire could initiate or exacerbate an accident at the reactor by precluding the presence and functioning of operating personnel. In other scenarios, the high radiation field produced by a core-melt accident could initiate or exacerbate a pool-fire scenario, again by precluding the presence and functioning of operating personnel. Many core-melt scenarios would involve the interruption of cooling to the pool.

By focusing on a pool fire accompanied by a reactor accident, this report does not imply that other pool-fire scenarios make a smaller contribution to pool-fire risks at Pilgrim and Vermont Yankee. Such a conclusion could come only from a comprehensive assessment of pool-fire risks, and no such assessment has ever been performed.

Tables 6-1 and 6-2 provide licensee estimates of core-damage frequency (probability) and radioactive-release frequency for the Pilgrim and Vermont Yankee reactors. Some of these estimates are from the Independent Plant Examination (IPE) and the Independent Plant Examination for External Events (IPEEE) that have been performed for each plant.42 The remaining estimates are from the Environmental Report (Appendix E of the license renewal application) for each plant. In this report, the IPE and IPEEE estimates are used instead of the 43 ER estimates, because the studies underlying the latter are not available for review.

Estimates shown in Tables 6-1 and 6-2 that are of particular relevance to this report are the estimates of the probability (frequency) of an early release of radioactive material from the reactor. Table 6-3 provides a definition of "early" and other terms that are used to categorize potential radioactive releases. "High" and "medium" release scenarios, as defined in Table 6-3, are often "early" and vice versa.

4! For present purposes, core damage is equivalent to core melt.

42 Boston Edison, 1992; Boston Edison, 1994; VYNPS, 1993; VYNPS, 1998.

43 NRC Public Document Room staff informed Diane Curran that the recent reactor-accident studies referenced in the Environmental Reports for Pilgrim and Vermont Yankee could not be located within the NRC.

Risks ofpool storage ofspentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 20 Lessons from a license-amendmentproceedingforthe Harrisplant This report assumes that the conditional probability of a spent-fuel-pool fire, given an early release from the adjacent reactor, is 50 percent. That assumption is reasonable -

and not necessarily conservative - for the Pilgrim or Vermont Yankee plant because the pool and the reactor are in close physical proximity within the same building, and some of their essential support systems are shared. Support for this assumption is provided by technical studies and opinions submitted to the Atomic Safety and Licensing Board (ASLB) in a license-amendment proceeding in regard to the expansion of spent-fuel-pool capacity at the Harris nuclear power plant. All three parties to the proceeding - the NRC Staff, Carolina Power and Light (CP&L), and Orange County - reached the same conclusion on an issue that is relevant to the above-stated conditional probability of 50 percent.

The Harris plant has one reactor and four pools. The reactor - a PWR - is in a cylindrical, domed containment building. The four pools are in a separate, adjacent building that was originally intended to serve four reactors. Only one reactor was built.

Two pools were in use at high density prior to the proceeding, and the proceeding addressed the activation of the two remaining pools, also at high density.

During the proceeding, the ASLB determined that the potential for a pool fire should be considered, and ordered the three parties to analyze a single scenario for such a fire.44 In the postulated scenario, a severe accident at the Harris reactor would contaminate the Harris site with radioactive material to an extent that would preclude actions needed to supply cooling and makeup to the Harris pools. Thereafter, the pools would boil and dry out, and fuel within the pools would burn. Following the ALSB's order, Orange County submitted a report by this author.4 5 The NRC Staff submitted an affidavit by members of the Staff.46 CP&L47

- the licensee - submitted a document prepared by ERIN Engineering.

Orange County's analysis found that the minimum value for the best estimate of a pool fire, for the ASLB's postulated scenario, is 1.6 per 100 thousand reactor-years. This estimate did not account for acts of malice, degraded standards of plant operation, or gross errors in design, construction or operation. The NRC Staff estimated, for the same scenario, that the probability of a pool fire is on the order of 2 per 10 million reactor-years. The ASLB accepted the Staffs estimate, thereby concluding that, for the particular configuration of the Harris plant, the postulated scenario is "remote and speculative"; the 44 ASLB, 2000.

45 Thompson, 2000.

46 Parry et al, 2000.

4' ERIN, 2000.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 21 48 ASLB then terminated the proceeding without conducting an evidentiary hearing.

Elsewhere, the author has described deficiencies in the ASLB's ruling.4 9 A major reason for the difference in the probability estimates proffered by Orange County and the NRC Staff was their differing assessments of the spread of radioactive material from the reactor containment building to the separate, adjacent pool building.

However, the Staff agreed with Orange County on some other matters. For example, the Staff reversed its previous position that comparatively long-discharged fuel will not ignite in the event of water loss from a high-density pool. Staff members stated that loss of water from pools containing fuel aged less than 5 years "would almost certainly result in an exothermic reaction", and also stated: "Precisely how old the fuel has to be to prevent a fire is still not resolved."50 Moreover, the Staff assumed that a fire would be inevitable if the water level fell to the top of the racks.

Most importantly for present purposes, the technical submissions of all three parties agreed that the onset of a pool fire in two of the pools in the Harris pool building would preclude the provision of cooling and water makeup to the other two pools. This effect would arise from the spread of hot gases and radioactive material throughout the pool building, which would preclude access by operating personnel. Thus, the pools not involved in the initial fire would boil and dry out, and their fuel would bum.

The Pilgrim and Vermont Yankee plants have a different configuration than the Harris plant, because at Pilgrim and Vermont Yankee the reactor and the pool are within the same building whereas at Harris they are in different buildings. Thus, the Pilgrim and Vermont Yankee plants are analogous to the Harris pool building. Given an early release from the Pilgrim or Vermont Yankee reactor as part of a core-melt accident, hot gases and radioactive material from the reactor would spread throughout the building that encloses both. Provision of cooling and water makeup to the pool would be precluded, the radiation field and the thermal environment being even more extreme than in the Harris situation. The pool would boil and dry out, and its fuel would bum.

Thus, the three parties' agreement in the Harris proceeding implies their agreement that a pool fire would inevitably follow an early release as part of a core-melt accident at Pilgrim or Vermont Yankee. Against that background, this report's assumption of a conditional probability of 50 percent for a pool fire, given an early release, is reasonable.

7. Initiation of a Pool Fire by Malicious Action The NRC's August 1979 Generic Environmental Impact Statement on handling and storage of spent fuel (NUREG-0575) considered potential sabotage events at a spent-fuel pool. 5' Table 7-1 describes the postulated events, which encompassed the detonation of 4

' ASLB, 2001.

49 Thompson, 2001 b.

50 Parry et al, 2000, paragraph 29.

" NRC, 1979, Section 5 and Appendix J.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 22 explosive charges in the pool, breaching of the walls of the pool building and the pool floor by explosive charges or other means, and takeover of the central control room for one half-hour. Involvement of up to 80 adversaries was implied.

NUREG-0575 did not, however, recognize the potential for an attack with these attributes to cause a fire in the pool. 52 Technically-informed attackers operating within this envelope of attributes could cause a fire in a pool at Pilgrim, Vermont Yankee or other plants. Informed attackers could use explosives, and their command of the control room for one half-hour, to drain water from the pool and release radioactive material from the reactor.53 The radiation field from the reactor release would preclude personnel access, thus precluding recovery actions if command of the plant were returned to the operators after one half-hour.

The potential for a maliciously-induced pool fire at Pilgrim or Vermont Yankee is influenced by several factors. Here, the following factors are considered: (i) the present level of protection of nuclear power plants and spent fuel; (ii) options for providing greater protection; (iii) available means of attack; and (iv) motives for attack. In the context of an EIS, the first, third and fourth of these factors relate to the probability of a successful attack, and the second factor relates to alternatives.

The present level ofprotection of nuclearpower plants and spentfuel Site-security measures mandated by the NRC have made access to a nuclear power plant more difficult for attackers approaching on foot or by land vehicle than was the case in 1979.54 Nevertheless, as discussed below, a successful attack could be mounted today using resources of the scale assumed in NUREG-0575 or employed to attack the United States on 11 September 2001. In light of information now available, the NRC could prepare a supplement to NUREG-0575 that updates its sabotage analysis. This supplement could employ a classified appendix to prevent public disclosure of sensitive information.

The consideration of sabotage events in NUREG-0575 is an exception. As a general rule, the NRC does not consider malicious acts in the context of license proceedings or environmental impact statements. The NRC's policy on this matter is illustrated by a September 1982 ruling by the Atomic Safety and Licensing Board in the operating-license proceeding for the Harris nuclear power plant. An intervenor, Wells Eddleman, had proffered a contention alleging, in part, that the plant's safety analysis was deficient because it did not consider the "consequences of terrorists commandeering a very large airplane55..... and diving it into the containment." In rejecting this contention the ASLB stated:

52 The sabotage events postulated in NUREG-0575 yielded comparatively small radioactive releases.

53In some areas of the Pilgrim or Vermont Yankee reactor building, one explosive charge could potentially breach the pool wall, the reactor containment, and the reactor vessel.

5 NRC, 2004; Thompson, 2004.

55 ASLB, 1982.

Risks ofpool storage of spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by MRSS, May 2006 Page 23 This part of the contention is barred by 10 CFR 50.13. This rule must be read in parimateria with 10 CFR 73.1 (a)(1), which describes the "design basis threat" against which commercial power reactors are required to be protected. Under that provision, a plant's security plan must be designed to cope with a violent external assault by "several persons," equipped with light, portable weapons, such as hand-held automatic weapons, explosives, incapacitating agents, and the like.

Read in the light of section 73.1, the principal thrust of section 50.13 is that military style attacks with heavier weapons are not a part of the design basis threat for commercial reactors. Reactors could not be effectively protected against such attacks without turning them into virtually impregnable fortresses at much higher cost. Thus Applicants are not required to design against such things as artillery bombardments, missiles with nuclear warheads, or kamikaze dives by large airplanes, despite the fact that such attacks would damage and may well destroy a commercial reactor.

As indicated by the ASLB, the NRC's basic policy on protecting nuclear facilities from attack is laid down in the regulation 10 CFR 50.13. This regulation was promulgated in September 1967 by the US Atomic Energy Commission (AEC) - which preceded 5 6 the NRC - and was upheld by the US Court of Appeals in August 1968. It states:

An applicant for a license to construct and operate a production or utilization facility, or for an amendment to such license, is not required to provide for design features or other measures for the specific purpose of protection against the effects of (a) attacks and destructive acts, including sabotage, directed against the facility by an enemy of the United States, whether a foreign government or other person, or (b) use or deployment of weapons incident to US defense activities.

Pursuant to 10 CFR 50.13, licensees are not required to design or operate nuclear facilities to resist enemy attack. However, events have obliged the NRC to progressively modify this position, so as to require greater protection against malicious or insane acts by sub-national groups. A series of events, including the 1993 bombing of the World Trade Center in New York, persuaded the NRC to introduce, in 1994, regulations requiring licensees to defend nuclear power plants against vehicle bombs. The attacks of 11 September 2001 led the NRC to require additional measures.

The NRC requires its licensees to defend against a design basis threat (DBT), a postulated attack that has become more severe over time. The present DBT was promulgated in April 2003. Prior to February 2002 the DBT was published, but not thereafter.57 The NRC has described the present DBT for nuclear power plants as follows:

56 Federal Register, Vol. 32, 26 September 1967, page 13445.

37 NRC Press Release No.03-053, 29 April 2003.

Risks ofpool storage of spentfitel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 24 The Order that imposes revisions to the Design Basis Threat requires power plants to implement additional protective actions to protect against sabotage by terrorists and other adversaries. The details of the design basis threat are safeguards information pursuant to Section 147 of the Atomic Energy Act and will not be released to the public. This Order builds on the changes made by the Commission's February 25, 2002 Order. The Commission believes that this DBT represents the largest reasonable threat against which a regulated private security force should be expected to defend under existing law. It was arrived at after extensive deliberation and interaction with cleared stakeholders from other Federal agencies, State governments and industry.

From this statement, and from other published information, it is evident that the NRC requires a comparatively light defense for nuclear power plants and their spent fuel. The scope of the defense does not reflect a full spectrum of threats. Instead, it reflects a consensus about the level of threat that licensees can "reasonably" be expected to resist. 58 A rationale for the present level of protection of nuclear facilities was articulated by the NRC chair, Richard Meserve, in 2002:59 If we allow terrorist threats to determine what we build and what we operate, we will retreat into the past - back to an era without suspension bridges, harbor tunnels, stadiums, or hydroelectric dams, let alone skyscrapers, liquid-natural-gas terminals, chemical factories, or nuclear power plants. We cannot eliminate the terrorists' targets, but instead we must eliminate the terrorists themselves. A strategy of risk avoidance -

the elimination of the threat by the elimination of potential targets - does not reflect a sound response.

Optionsforproviding greaterprotection Chairman Meserve's statement does not consider another approach - designing new infrastructure elements or modifying existing elements so that they are more robust against attack. It has been known for decades that nuclear power plants could be designed to be more robust against attack. For example, in the early 1980s the reactor vendor ASEA-Atom developed a preliminary design for an "intrinsically safe" commercial reactor known as the PIUS reactor. Passive-safety design principles were used. The design basis for the PIUS reactor included events such as equipment failures, operator errors and earthquakes, but also included: (i) takeover of the plant for one operating shift by knowledgeable saboteurs equipped with large amounts of explosives; (ii) aerial bombardment with 1,000-pound bombs; and (iii) abandonment of the plant by the operators for one week.6° 58 59 Fertel, 2006; Wells, 2006; Brian, 2006.

Meserve, 2002, page 22.

6Hannerz, 1983.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 25 As explained in Section 8, below, the spent-fuel pools at the Pilgrim and Vermont Yankee plants would be more robust against attack if they were re-equipped with low-density, open-frame storage racks. This step would restore the pools to their original design configuration.

Available means of attack In considering the potential for a future attack on the Pilgrim or Vermont Yankee spent-fuel pool, it is necessary to consider both means and motives. Table 7-2 provides some general information about means. This table shows that nuclear power plants are vulnerable to attack by means available to sub-national groups. For example, one of the potential instruments of attack shown in Table 7-2 is an explosive-laden smaller aircraft.

In this connection, note that the US General Accounting Office (GAO) expressed concern, in September 2003 testimony to Congress,6 about the potential for malicious use of general-aviation aircraft. The testimony stated: 1 Since September 2001, TSA [the Transportation Security Administration]

has taken limited action to improve general aviation security, leaving it far more open and potentially vulnerable than commercial aviation. General aviation is vulnerable because general aviation pilots are not screened before takeoff and the contents of general aviation planes are not screened at any point. General aviation includes more than 200,000 privately owned airplanes, which are located in every state at more than 19,000 airports. Over 550 of these airports also provide commercial service. In the last 5 years, about 70 aircraft have been stolen from general aviation airports, indicating a potential weakness that could be exploited by terrorists.

Sub-national groups could obtain explosive devices that would be effective instruments of attack on a nuclear power plant. 62 Assistance from a government or access to classified information would not be required. Designs for sophisticated explosive devices capable of exploiting the vulnerabilities of the Pilgrim or Vermont Yankee spent-fuel pools are publicly available from sources including the web. Means for delivery of such devices to the target are also readily available. 63 Motivesfor attack Understanding the factors that could motivate a sub-national group to attack a civilian nuclear facility in the USA is a difficult task. Multiple, competing factors will be in play, and will affect different groups in different ways. An attacking group might be foreign, as was the case in New York and Washington in September 2001, or domestic, as was the case in Oklahoma City in April 1995 and London in July 2005. As we try to understand 61 Dillingham, 2003, page 14.

62 Walters, 2003.

63 For example: Raytheon, 2004; the website www.aircraftdealer.com, accessed 6 November 2004.

Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 26 the complex issue of motives, one requirement is clear. We must set aside our own perspectives, and attempt to understand the perspectives of those who might attack us.

That understanding will help us to assess risks and prepare countermeasures.

One insight from experience is that an attack by a sub-national group could be part of an action-reaction cycle. 64 Former CIA Director Stansfield Turner has recounted how the October 1983 truck bombing of a US Marine barracks in Beirut was part of such a cycle. 65 A high-level task force convened by the Council on Foreign Relations recognized the potential for an action-reaction effect in the context of US military operations with counterterrorism objectives. They recommended that this effect be offset by greater protection of domestic targets. An October 2002 report of the task force stated:66 Homelandsecurity measures have deterrence value:

US counterterrorism initiatives abroad can be reinforced by making the US homeland a less tempting target. We can transform the calculations of would-be terrorists by elevating the risk that (1) an attack on the United States will fail, and (2) the disruptive consequences of a successful attack will be minimal. It is especially critical that we bolster this deterrent now since an inevitable consequence of the US government's stepped-up military and diplomatic exertions will be to elevate the incentive to strike back before these efforts have their desired effect.

Probabilityofattack For policy and planning purposes, it would be useful to have an estimate of the probability of an attack-induced spent-fuel-pool fire. The record of experience does not allow a statistically valid estimate of this probability. A decision maker or risk analyst must, therefore, rely on prudent judgment.67 In the case of an attack-induced spent-fuel-pool fire in the USA, prudent judgment indicates that a probability of at least one per century is a reasonable assumption for policy purposes.

8. Options to Reduce the Risks of Pool Fires Various options are available to reduce the probability and/or magnitude of an atmospheric release from a spent-fuel-pool fire at Pilgrim or Vermont Yankee. A useful option must achieve one or more of the following five effects: (i) reduce the probability of a loss of water; (ii) reduce the potential for ignition of fuel following a loss of water; (iii) reduce the potential for fire propagation following ignition of one or more fuel 64Davis, 2006.

65 Turner, 1991.

6Hart et al, 2002, pp 14-15.

67 The NRC has used qualitative judgment about the probability of attack as a basis for the 1994 vehicle-bomb rule and the present design basis threat.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 27 assemblies; (iv) reduce the inventory of spent fuel in the pool; or (v) suppress a fire in the pool.

The fifth effect - fire suppression - would be extremely difficult to achieve. Spraying water on a fire could feed a zirconium-steam reaction. In principle, an air-zirconium reaction in the pool could be smothered, perhaps by spreading large amounts of a non-reactive powder. In practice, the high radiation field surrounding the pool would preclude the approach of firefighters. Here, the focus is on the first four effects.

Table 8-1 describes selected risk-reducing options that could, to some degree, achieve one or more of the first four effects. This table does not purport to identify a comprehensive set of risk-reducing options, or to provide a complete assessment of the listed options. Instead, this table illustrates the range of options and their properties.

The option that would achieve the largest risk reduction, during plant operation within a license extension period, would be to re-equip the pool with low-density, open-frame storage racks. Implementation of this option would return the plant to its original design configuration. Excess spent fuel would be placed in dry storage at the plant site. This option would not reduce the probability of a loss of water. Instead, it would allow the pool to survive a loss of water without damage to the fuel. It would prevent ignition of fuel in almost all scenarios of water loss. For the few, unlikely scenarios that would remain, it would inhibit fire propagation across the pool. By reducing the inventory of radioactive material in the pool, this option would limit the magnitude of the greatest possible release.

Re-equipping a spent-fuel pool with low-density, open-frame racks would be an entirely passive measure of risk reduction. Successful functioning of this option would not require electricity, a water supply, the presence of personnel, or any other active function.

Passive risk-reduction measures of this type represent good practice in nuclear engineering design. Reactor vendors are seeking to use passive-safety principles in the design of new commercial reactors.

Nuclear power plants are important elements of the nation's critical infrastructure. Other "elements of that infrastructure also offer opportunities to use passive measures of risk reduction. Passive measures can be highly reliable and predictable in their effectiveness.

They can substitute for other measures to protect critical infrastructure, as shown in Table 8-2, yielding monetary and non-monetary benefits.

Table 8-3 provides an estimated cost for offloading spent fuel from the Pilgrim or Vermont Yankee pool, to allow the pool to be re-equipped with low-density, open-frame racks. There would be an additional, smaller cost for replacing the racks, which is neglected here. Note that Table 8-3 does not purport to provide a definitive specification for re-equipment of the pools, or a final estimate of the cost of this option. The analysis presented in Table 8-3 is illustrative. A more sophisticated analysis would not alter the basic findings of this report.

Risks ofpool storage of spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 28 From Table 8-3 one sees that the estimated cost of a transition to low-density, open-frame racks would be $54-109 million at Pilgrim and $43-87 million at Vermont Yankee.

Approximately the same cost would otherwise be incurred during decommissioning of the plant, when spent fuel would be offloaded from the pool to dry storage. The net additional cost of the option would reflect the comparative present values of approximately equal expenditures now or two decades in the future.

9. An Integrated View of Risks and Risk-Reducing Options Preceding sections of this report have discussed particular aspects of the risks and risk-reducing options associated with pool storage of spent nuclear fuel. To produce useful policy findings, these separate discussions must be integrated.

Section 6 of this report provides, in Tables 6-1 and 6-2, licensee estimates of the probability of an early release as part of a severe reactor accident - of non-malicious origin - at Pilgrim or Vermont Yankee. Also, Section 6 develops the reasonable assumption that the conditional probability of a spent-fuel-pool fire, given an early release from the reactor, is 50 percent. Section 7 sets forth a judgment that the probability of a successful, attack-induced spent-fuel-pool fire in the USA can be assumed, for policy purposes, to be at least one per century. Section 8 provides an estimate that the cost of a transition to low-density, open-frame racks in a spent-fuel pool would be $54-109 million at Pilgrim and $43-87 million at Vermont Yankee.

Table 9-1 combines the findings of Sections 6 and 7, yielding an estimate that the total probability of a pool fire at Pilgrim or Vermont Yankee is 1.2 per 10,000 years at each plant. A number of simplifying assumptions are employed in Table 9-1, as is evident from the table. A more sophisticated analysis would not alter the general findings of this report.

Entergy's Environmental Reports for Pilgrim and Vermont Yankee present a cost-versus-benefit analysis as a means of evaluating Severe Accident Mitigation Alternatives. Table 9-2 illustrates this type of analysis. The table shows that an investment of$110-200 million (depending on discount rate) is justified to prevent a radioactive release with a probability of one per 10,000 years and a consequence cost of $100 billion.

A companion report by Dr. Jan Beyea shows that the consequence cost attributable to a spent-fuel-pool fire at Pilgrim or Vermont Yankee would exceed $100 billion across a range of release scenarios.6 8 This report estimates that the probability of a pool fire at Pilgrim or Vermont Yankee is more than one per 10,000 years at each plant. Re-equipping the Pilgrim or Vermont Yankee pool with low-density, open-frame racks would substantially reduce the probability of a pool fire and the magnitude of its 6 The findings in Dr. Beyea's companion report are consistent with previous analysis provided in: Beyea et al, 2004.

Risks ofpool storage ofspentffuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 29 consequences. To a first-order approximation, re-equipping a pool in this manner would eliminate the risk of a pool fire. The cost of re-equipping a pool would be less than $110 million. Thus, a SAMA-type analysis shows that re-equipping both pools with low-density, open-frame racks is justified.

The analysis underlying this conclusion does not purport to be comprehensive. This analysis is, however, sufficient to show that Entergy and the NRC are obliged to perform new studies, as described in Section 10, below.

Probabilistic analysis, of the type that is used in Table 9-1 and in Entergy's Environmental Reports, should not be the only means of evaluating Severe Accident Mitigation Alternatives. People who are unfamiliar with probabilistic risk assessment may place unwarranted faith in the numerical values that it generates. A closer look at probabilistic risk assessment for nuclear power plants shows that its findings are plagued by incompleteness and uncertainty. 69 These findings cannot substitute for prudent, informed judgment. In exercising that judgment, decision makers should be aware of strategic considerations, such as those addressed in Table 8-2.

10. Analysis Required From Entergy and the Nuclear Regulatory Commission Entergy's Environmental Reports for the Pilgrim and Vermont Yankee plants do not examine the potential for a radioactive release from a fire in a spent-fuel pool. Nor do they consider SAMA-type options that could reduce the probability and/or magnitude of such a release. Similarly, the NRC does not consider such options in its GEIS for re-licensing of nuclear power plants.

Yet, the NRC has determined that the potential for a reactor core-melt accident must be considered in a re-licensing EIS. Moreover, a spent-fuel-pool fire at Pilgrim or Vermont Yankee has, according to this report, a probability comparable to the probability of a reactor core-melt accident. Finally, the offsite radiological impact of the pool fire could be substantially greater than the impact of the core-melt accident, because the pool has a larger inventory of cesium-137. Therefore, the potential for a pool fire should be' considered in an Environmental Report or EIS for re-licensing. Such studies should use at least the depth of analysis that is employed to consider the potential for a core-melt accident.

Entergy should withdraw, revise and re-submit its Environmental Reports. In addressing the potential for pool fires, each revised ER should consider the full range of potential initiating events, including acts of malice. Options for reducing the risks of pool fires should be considered to at least the depth of analysis that is employed for SAMAs in the context of reactor accidents.

69 Hirsch et al, 1989.

Risks ofpool storageof spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by MRSS, May 2006 Page 30 The NRC should prepare generic supplements to its August 1979 Generic Environmental Impact Statement on handling and storage of spent fuel (NUREG-0575), and its May 1996 GEIS on license renewal (NUREG-1437). These supplements should address the risks of spent-fuel-pool fires to at least the depth of analysis and experiment that was conducted to prepare the NRC's December 1990 study on the risks of reactor accidents (NUREG-1 150).70 In addition, the supplements should identify a range of options to reduce the risks of pool fires, and should comprehensively assess the benefits and costs of these options. An EIS prepared for re-licensing of Pilgrim or Vermont Yankee should incorporate the findings of the new, generic supplements to NUREG-0575 and NUREG-1437.

11. Conclusions Discussions in preceding sections of this report lead to the following major conclusions:

C1. At the Pilgrim and Vermont Yankee plants, large amounts of spent nuclear fuel are stored in water-filled pools equipped with high-density, closed-form storage racks.

Entergy plans to continue this practice during the period of license extension, operating the pools at near to full capacity.

C2. The radioactive isotope cesium-137 provides a useful indicator of the hazard potential of the Pilgrim and Vermont Yankee spent-fuel pools. During the period of license extension, it is likely that these pools will hold about 1.6 million TBq (Pilgrim) and 1.4 million TBq (Vermont Yankee) of cesium-137. Each pool will hold about 8 times as much cesium-137 as will be present in the adjacent reactor.

C3. Various studies by the NRC and other bodies have shown that loss of water from a spent-fuel pool equipped with high-density, closed-form storage racks would, over a range of scenarios, lead to self-ignition of some of the fuel assemblies in the pool, leading to a fire that could propagate across the pool. Burning of fuel assemblies would lead to a large atmospheric release of cesium-137 and other radioactive isotopes. These findings have been confirmed by a 2005 report prepared by the National Academy of Sciences at the request of the US Congress.

C4. Entergy has submitted an Environmental Report (ER) as part of each license extension application. Each ER examines potential reactor accidents involving damage to the reactor core and release of radioactive material to the atmosphere. That examination supports the ER's evaluation of Severe Accident Mitigation Alternatives (SAMAs) - options that could reduce the probability and/or magnitude of a radioactive release from the reactor. Neither ER examines the potential for a radioactive release from a fire in a spent-fuel pool, or considers SAMA-type options that could reduce the probability and/or magnitude of such a release.

7 oNRC, 1990b.

4 4 Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 31 C5. The NRC has published various documents that discuss aspects of the potential for a spent-fuel-pool fire. Only three of these documents are products of processes that provided an opportunity for formally structured public comment and, potentially, for in-depth analysis of risks and alternatives. One document is the August 1979 Generic Environmental Impact Statement (GEIS) on handling and storage of spent fuel (NUREG-0575). The second document is the May 1996 GEIS on license renewal (NUREG-1437).

These two documents purported to provide systematic analysis of the risks and relative costs and benefits of alternative options. The third document is a September 1990 review (55 FR 38474) of the NRC's Waste Confidence Decision. That document did not purport to provide an analysis of risks and alternatives. None of the three documents provides a technically defensible examination of spent-fuel-pool fires and the associated risks and alternatives. The findings in each document are inconsistent with the more recent and more credible findings of the National Academy of Sciences, set forth in its 2005 report, and the findings of other studies conducted since 1996.

C6. The August 1979 GElS (NUREG-0575) considered potential sabotage events at a spent-fuel pool. The GEIS did not recognize the potential for an attack with the postulated attributes to cause a fire in the pool. Technically-informed attackers operating within this envelope of attributes could, with high confidence, cause an unstoppable fire in a pool.

C7. Site-security measures mandated by the NRC have made access to a nuclear power plant more difficult for attackers approaching on foot or by land vehicle than was the case in 1979. Nevertheless, a successful attack could be mounted using resources of the scale assumed in NUREG-0575 or employed to attack the United States on 1 September 2001. The NRC has not prepared any environmental impact statement or comparable study that updates the sabotage analysis set forth in NUREG-0575.

C8. The record of experience does not allow a statistically valid estimate of the probability of an attack-induced spent-fuel-pool fire in the USA. Prudentjudgment indicates that a probability of at least one per century is a reasonable assumption for policy purposes. This translates to a probability of one per 10,000 years at Pilgrim or Vermont Yankee, which is comparable to the estimated probability of a reactor core-melt accident according to probabilistic risk studies done for these plants.

C9. Probabilistic risk studies done by licensees for the Pilgrim and Vermont Yankee plants can support an estimate of the probability of a spent-fuel-pool fire that is caused by or accompanies a core-melt accident at the adjacent reactor. The connection between these events is particularly strong at these plants because the pool and the reactor are in close physical proximity within the same building, and some of their essential support systems are shared. A provisional estimate of the probability of a spent-fuel-pool fire associated with a core-melt accident, not involving malice, is about two per -100,000 years at each plant.

Risks ofpool storage ofspentfiel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 32 CIO. Options are available to reduce the probability and/or magnitude of an atmospheric release from a spent-fuel-pool fire at Pilgrim or Vermont Yankee. The option that would achieve the largest risk reduction, during plant operation within a license extension period, would be to re-equip the pool with low-density, open-frame racks. This step would return the plant to its original design configuration. Excess spent fuel would be placed in dry storage at the plant site. The estimated cost of this option would be $54-109 million at Pilgrim and $43-87 million at Vermont Yankee. Approximately the same cost would otherwise be incurred during decommissioning of the plant, when spent fuel would be offloaded from the pool to dry storage. The net additional cost of the option would reflect the comparative present values of approximately equal expenditures now or two decades in the future.

C11. Re-equipping a spent-fuel pool with low-density, open-frame racks would be a passive measure that would eliminate most scenarios for a pool fire and greatly reduce the atmospheric release for the few, unlikely scenarios that would remain. Passive risk-reduction measures of this type represent good practice in nuclear engineering design.

Substantial benefits, both monetary and non-monetary, could arise from the deployment of passive risk-reduction measures at nuclear power plants and other elements of critical infrastructure.

C12. Entergy's Environmental Reports present a cost-versus-benefit analysis as a means of evaluating Severe Accident Mitigation Alternatives. This type of analysis should not be the only basis for evaluating SAMAs, but can provide useful information. The analysis shows that an investment of $110-200 million (depending on discount rate) is justified to prevent a radioactive release with a probability of one per 10,000 years and a consequence cost of $100 billion. A companion report by Dr. Jan Beyea shows that the consequence cost attributable to a spent-fuel-pool fire at Pilgrim or Vermont Yankee would exceed $100 billion across a range of release scenarios. Given the pool-fire probability found in this report (at least one per 10,000 years), and the estimated cost of re-equipping the Pilgrim or Vermont Yankee pool with low-density, open-frame racks (less than $110 million), re-equipment of both pools in this manner is justified.

C13. The NRC has determined that the potential for a reactor core-melt accident must be considered in an environmental impact statement for the re-licensing of a nuclear power plant. Thus, the NRC has determined that such an accident is neither remote nor speculative. A spent-fuel-pool fire at Pilgrim or Vermont Yankee has, by estimation in this report, a probability comparable to the probability of a reactor core-melt accident.

The offsite radiological impact of the pool fire could be substantially greater than the impact of the core-melt accident. Therefore, the potential for a pool fire should be considered in a re-licensing EIS to at least the depth accorded the consideration of a core-melt accident.

C14. Entergy should withdraw, revise and re-submit its Environmental Reports for Pilgrim and Vermont Yankee. The revised ERs should address the potential for pool fires to at least the depth of analysis that is employed for reactor accidents. The pool-fire

Risks ofpool storage ofspentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 33 analysis should consider the full range of potential initiating events, including acts of malice. Options for reducing the risks of pool fires should be considered to at least the depth of analysis that is employed for SAMAs in the context of reactor accidents.

C 15. The NRC should prepare supplements to its August 1979 Generic Environmental Impact Statement on handling and storage of spent fuel (NUREG-0575), and its May 1996 GEIS on license renewal (NUREG-1437). These supplements should address the risks of spent-fuel-pool fires to at least the depth of analysis and experiment that was conducted to prepare the NRC's December 1990 study on the risks of reactor accidents (NUREG-1 150). Acts of malice should be considered. In addition, the supplements should identify a range of options to reduce the risks of pool fires, and should comprehensively assess the benefits and costs of these options.

Risks ofpool storage ofspentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 34

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William Walters, "An Overview of the Shaped Charge Concept", paper presented at the 11th Annual ARL/USMA Technical Symposium, 5 and 7 November 2003. (This symposium was sponsored by the Mathematical Sciences Center of Excellence at the US Military Academy (USMA) and hosted by the US Army Research Laboratory (ARL) and USMA.)

(Wells, 2006)

Jim Wells, US Government Accountability Office, testimony before the Subcommittee on National Security, Emerging Threats and International Relations, US House Committee on Government Reform, "Nuclear Power Plants Have Upgraded Security, but the Nuclear Regulatory Commission Needs to Improve Its Process for Revising the Design Basis Threat", 4 April 2006.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 40 Table 3-1 Selected Characteristics of the Pilgrim and Vermont Yankee Plants Characteristic Pilgrim Vermont Yankee Reactor type BWR Mark 3 BWR Mark 4 Containment type Mark 1: Drywell and free- Mark 1: Drywell and free-standing torus standing torus Rated power 2,028 MWt 1,593 MWt; application pending for 20% uprate to 1,912 MWt Number of fuel assemblies 580 368 in reactor core Date of first commercial December 1972 November 1972 operation Date of expiration of June 2012 March 2012 present operating license Heat sink Ocean Connecticut River and/or cooling towers Inventory of cesium-137 in 1.90E+17 Bq 1.79E+17 Bq reactor core (Assumed power: 2,028 (Assumed power: 1,912 MWt) MWt)

Sources:

(a) Jay R. Larson, System Analysis Handbook,NUREG/CR-4041, USNRC, November 1985.

(b) License renewal application, Appendix E (for each plant).

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 41 Table 3-2 Selected Characteristics of the Spent-Fuel Pools at the Pilgrim and Vermont Yankee Plants Characteristic Pilgrim Vermont Yankee Licensed capacity 3,859 fuel assemblies

• In 1988: 2,870 fuel assemblies; unused floor space could hold racks with potential additional capacity of about 360 assemblies

• At present: 3,355 fuel assemblies, incl. temporary, 266-cell rack in cask position Inventory at end of 2002 2,274 fuel assemblies 2,671 fuel assemblies Capacity needed for full- 580 fuel assemblies. 368 fuel assemblies core discharge Floor dimensions 40 ft 4 in by 30 ft 6 in; 40 ft 0 in by 26 ft 0 in; 5 ft 8 in thick 5 ft 0 in thick including 11 in of grout Depth 38 ft 9 in 38 ft 9 in Wall thicknesses Reactor shield wall forms Reactor shield wall forms one face; thicknesses of one face; thicknesses of other walls range from 4 ft other walls range from 4 ft I in to 6 ft I in. 6 in to 6 ft 0 in.

Typical spent fuel assembly General Electric 8x8; General Electric 8x8; 210 kgU per assembly 210 kgU per assembly Sources:

(a) USNRC documentation of Amendment No. 155, Pilgrim operating license.

(b) USNRC documentation of Amendment No. 104, Vermont Yankee operating license.

(c) P. G. Prassinos et al, Seismic Failureand Cask DropAnalyses of the Spent FuelPools at Two RepresentativeNuclear Power Plants,NUREG/CR-5176,USNRC, January 1989.

(d) Vermont Yankee Nuclear Power Corporation, Vermont Yankee Spent Fuel Storage Rack Replacement Report, April 1986.

(e) Holtec International, PilgrimNuclearPower Station Spent Fuel Storage Capacity Expansion, 5 January 1993..

(f) USNRC, GenericEIS on Handlingand Storage of Spent Light Water Power Reactor Fuel,NUREG-0575, August 1979.

(g) Anthony Andrews, Spent Nuclear Fuel Storage Locations andInventory, CRS Report for Congress, 21 December 2004.

(h) John Hoffman, pre-filed testimony to Vermont Public Service Board on behalf of Entergy Nuclear Vermont Yankee, LLC, 16 June 2005.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 42 Table 3-3 Estimation of Cesium-137 Inventory in a Spent-Fuel Assembly and the Reactor Core, for the Pilgrim and Vermont Yankee Plants Estimation Step Pilgrim Vermont Yankee Fuel burnup at discharge B MWt-days per kgU B MWt-days per kgU Discharge burnup assuming 21OxB MWt-days per 2lOxB MWt-days per each fuel assembly has a assembly assembly mass of 210 kgU Reactor characteristics

• Rated power: 2,028 MWt

• Rated power: 1,912 MWt

- 580 fuel assemblies

• 368 fuel assemblies Av. rated power per 2,028/580 = 3.50 MWt 1,912/368 = 5.20 MWt assembly Av. full-power days per 21OxB/3.50 = 60.OxB days 21OxB/5.20 = 40.4xB days assembly Av. full-power days per 1,800 days = 4.93 yr 1,212 days = 3.32 yr assembly, assuming B = 30 Av. actual days of exposure 2,000 days = 5.48 yr 1,347 days = 3.69 yr per assembly, assuming plant capacity factor = 0.90 Cesium-137 inventory in 7.24E+14 Bq 7.39E+14 Bq av. fuel assembly at completion of exposure Approx. core inventory of ((7.24E+14)/2)x580 = ((7.39E+14)/2)x368 =

cesium-137 2.10E+17 Bg 1.36E+17 Bg Core inventory of cesium- 1.90E+17 Bq 1.79E+17 Bq 137 as reported in Appendix E of license renewal application Notes:

Here, calculation of the cesium-137 inventory in an average fuel assembly assumes steady-state fission of uranium-235 with an energy yield of 200 MeV per fission and a cesium-137 fission yield of 6.2 percent, over the actual days of exposure with a constant power level of 0.90 times the rated power level.

Risks ofpool storage ofspentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 43 Table 3-4 Estimated Future Inventory and Selected Characteristics of Spent Fuel in Pools at the Pilgrim and Vermont Yankee Plants Estimation Step Pilgrim Vermont Yankee Licensed capacity 3,859 fuel assemblies 3,089 fuel assemblies (Not including temporary, 266-cell rack in cask position)

Capacity needed for full- 580 fuel assemblies 368 fuel assemblies core discharge Assumed periodic offload Offload to fill 3 modules, Offload to fill 3 modules, of older fuel assemblies to each of 68-assembly each of 68-assembly onsite dry-storage modules capacity: 204 assemblies capacity: 204 assemblies Average inventory of spent 3,859 - 580 - 204/2 = 3,089 - 368 - 204/2 =

fuel, assuming pool used at 3,177 fuel assemblies 2,619 fuel assemblies near-full capacity Av. period of exposure of 5.48 yr 3.69 yr assembly in core, assuming burnup of 30 MWt-days per kgU and plant capacity factor of 0.90 Av. age of fuel assemblies (3,177/(580/5.48))/2 (2,619/(368/3.69))/2 =

after discharge to pool 15.0 yr 13.1 yr Cesium-137 in av. fuel 7.24E+14 Bq 7.39E+14 Bq assembly at discharge Cesium-137 in pool, 1.63E+18 Bq 1.43E+18 Bq assuming all assemblies at (44.1 MCi) (38.6 MCi) average age Mass of zirconium in pool, 191,000 kg 157,000 kg assuming 60 kg per fuel assembly Notes:

Data on a General Electric 8x8 fuel assembly are provided in Table G.4 of: USNRC, Generic EIS on Handlingand Storage ofSpent Light Water Power Reactor Fuel, NUREG-0575, August 1979. The total mass of an assembly is 275 kg and the mass of uranium is 210 kg. If all non-U mass were Zr, then the mass ratio of Zr to U would be 0.31. For comparison, masses of U and Zr in the core of the Peach Bottom BWR are provided in Table 4.7 of: M. Silberberg et al, Reassessment of the Technical Basesfor Estimating Source Terms, NUREG-0956, USNRC, July 1986. The U mass is 138 Mg and the Zr mass is 64.1 Mg. Thus, the mass ratio of Zr to U in the core is 0.46. In the table above, it is assumed that each fuel assembly contains 60 kg of Zr, representing a Zr-to-U mass ratio of 0.29.

Risks ofpool storage of spentfitel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 44 Table 3-5 Illustrative Inventories of Cesium-137 Case Inventory of Cesium-137 (TBq)

Produced during detonation of a 10-kilotonne 67 fission weapon Released to atmosphere during Chernobyl reactor 89,000 accident of 1986 Released to atmosphere during nuclear-weapon tests, 740,000 primarily in the 1950s and 1960s (Fallout was non-uniformly distributed across the planet, mostly in the Northern hemisphere.)

In Pilgrim spent-fuel pool during period of license 1,630,000 extension In Vermont Yankee spent-fuel pool during period of 1,430,000 license extension In Pilgrim reactor core 190,000 In Vermont Yankee reactor core 179,000 Notes:

(a) I Tbq = 1.0E+12 Bq = 27.0 Ci (b) Inventories in the first three rows are from Table 3-2 of: Gordon Thompson, Reasonably ForeseeableSecurity Events: Potentialthreats to optionsfor long-term management of UK radioactive waste, A report for the UK government's Committee on Radioactive Waste Management, IRSS, 2 November 2005.

(c) Inventories in the fourth and fifth rows are author's estimates set forth in this report.

(d) Inventories in the sixth and seventh rows are from Appendix E of the license renewal application for each plant.

Risks ofpool storageof spentfiel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by MRSS, May 2006 Page 45 Table 4-1 Estimated Duration of Phases of Implementation of the Yucca Mountain Repository Phase of Repository Duration of Phase (years)

Implementation If Yucca Mountain If Yucca Mountain Total Inventory of Total Inventory of Commercial Spent Commercial Spent Fuel = 63,000 MgU Fuel = 105,000 MgU Construction phase 5 5 Operation and Development 22 36 monitoring phases Emplacement 24-50 38-51 Monitoring 76-300 62-300 Closure phase 10-17 12-23 Notes:

(a) These estimates are from the Final EIS for Yucca Mountain, DOE/EIS-0250F, Volume 1,February 2002, pages 8-8 and 2-18.

(b) The Development and Emplacement phases would begin on the same date. Other phases would be sequential.

(c) The Construction phase would begin with issuance of construction authorization, and end with issuance of a license to receive and dispose of radioactive waste.

Risks ofpool storage of spentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 46 Table 4-2 Potential Emplacement Area of the Yucca Mountain Repository for Differing Spent-Fuel Inventories and Operating Modes Total Inventory of Emplacement Area (acres)

Commercial Spent Fuel in Higher-Temperature Lower-Temperature Repository (MgU) Operating Mode Operating Modes 63,000 1,150 1,600 to 2,570 105,000 1,790 2,480 to 3,810 Source: Final EIS for Yucca Mountain, DOE/EIS-0250F, Volume 1,February 2002, page 8-9.

Table 4-3 Estimated Number of Radioactive-Waste Shipments to the Yucca Mountain Site Source: Final EIS for Yucca Mountain, DOE/EIS-0250F, Volume I, February 2002, page 8-8.

Risks ofpool storageof spentfiel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 47 Table 4-4 Characteristics of BWR-Spent-Fuel Storage Canisters or Disposal Packages Proposed for Use at the Monticello or Skull Valley ISFSIs, or at Yucca Mountain Category Characteristics of Storage Canister or Disposal Package NUHOMS 61BT HI-STORM 100 Proposed Disposal Storage Canister MPC-68 Storage Package for (proposed for Canister (proposed Emplacement in Monticello ISFSI) for Skull Valley) Yucca Mountain Vendor Transnuclear West Holtec Unknown Capacity 61 68 24 or 44 (number of BWR fuel assemblies)

Wall thickness 0.5 in. 0.5 in. 2.0 in.

(stainless steel) (stainless steel) (stainless steel) plus 0.8 in. outer layer (Alloy 22)

Length 196.0 in. 190.3 in. 201.0 in. (for 24 assemblies) or 203.3 in. (for 44 assemblies)

Diameter 67.2 in. 68.4 in. 51.9 in. (for 24 assemblies) or 65.9 in. (for 44 assemblies)

Neutron absorber Boral Boral Borated stainless material steel Fill gas Helium Helium Helium Presence of No No No for 24 aluminum thermal assemblies, shunts to transfer Yes for 44 interior heat to wall assemblies of vessel ?

Notes:

(a) NUHOMS data are from: Xcel Energy's Application to the Minnesota PUC for a Certificate of Need to Establish an ISFSI at the Monticello Generating Plant, 18 January 2005, Section 3.7; and Transnuclear West's FSAR for the Standardized NUHOMS system, Revision 6, non-proprietary version, October 2001.

(b) HI-STORM data are from Holtec's FSAR for the HI-STORM 100 system, Holtec Report HI-2002444, Revision 1.

(c) Characteristics of the Yucca Mountain package are from the Yucca Mountain Science and Engineering Report, DOE/RW-0539, May 2001, Section 3.

Risks ofpool storageof spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 48 Table 5-1 Estimated Source Term for Atmospheric Release from Spent-Fuel-Pool Fire at the Pilgrim or Vermont Yankee Plant Indicator Pilgrim Vermont Yankee

• • Large Release **

Release to atmosphere of 1.63E+18 Bq 1.43E+18 Bq 100% of cesium-137 in pool Thermal power of fire, 191,000x12.1/(5x60x60) = 157,000x12.l/(5x60x60) assuming oxidation of 128 MW 106 MW 100% of Zr over 5 hrs I

• • SmallerRelease **

Release to atmosphere of 1.63E+17 Bq 1.43E+17 Bq 10% of cesium-137 in pool Thermal power of fire, 19,100x12.1/(0.5x60x60) = 15,700x12.1/(0.5x60x60)=

assuming oxidation of 10% 128 MW 106 MW of Zr over 0.5 hrs Notes:

(a) Pool inventories of cesium-137 and zirconium are from Table 3-4.

(b) The heat of reaction of Zr with oxygen or water is provided in table 3-1 of: Louis Baker Jr. and Robert C. Liimatainen, "Chemical Reactions", Chapter 17 in T. J.

Thompson and J. G. Beckerley (editors), The Technology of Nuclear Reactor Safety, MIT Press, 1973. The heat of reaction with oxygen is 12.1 MJ/kg, and the heat of reaction with water (steam) is 6.53 MJ/kg. In the table above, it is assumed that Zr reacts with air (oxygen).

Risks ofpool storage of spentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 49 Table 6-1 Licensee Estimates of Core Damage Frequency and Radioactive Release Frequency, Pilgrim Plant Indicator Source of Estimate Estimated Est. Frequency Frequency Adjusted (by factor of 6) to Account for External Events &

Uncertainty Core damage freq. License renewal 6.4E-06 per yr 3.8E-05 per yr (internal events) application, App. E Core damage License renewal 1.9E-05 per yr Not relevant frequency (fires) application, App. E Core damage freq. License renewal 3.2E-05 per yr Not relevant (earthquakes) application, App. E Large, early release License renewal 1.1 E-07 per yr 6.8E-07 per yr frequency (internal application, App. E events)

Medium, early License renewal 6.5E-08 per yr 3.9E-07 per yr release frequency application, App. E (internal events)

Core damage IPE, September 5.8E-05 per yr This adjustment not frequency (internal 1992 used in this source events)

Core damage IPEEE, July 1994 2.2E-05 per yr Not relevant frequency (fires)

Core damage IPEEE, July 1994 5.8E-05 per yr Not relevant frequency (EPRI)

(earthquakes) 9.4E-05 per yr (LLNL)

Early release IPE, September 1.3E-05 per yr This adjustment not frequency (internal 1992 used in this source events)

Early release IPEEE, July 1994 1.6E-05 per yr Not relevant frequency (EPRI)

(earthquakes) 3.2E-05 per yr (LLNL)

Risks ofpool storage of spentfiel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 50 Table 6-2 Licensee Estimates of Core Damage Frequency and Radioactive Release Frequency, Vermont Yankee Plant Indicator Source of Estimate Estimated Est. Frequency Frequency Adjusted (by factor of 10) to Account for External Events &

Uncertainty Core damage License renewal 5.OE-06 per yr 5.0E-05 per yr frequency (internal application, App. E events)

Core damage License renewal 5.613-05 per yr Not relevant frequency (fires) application, App. E Core damage License renewal Not estimated in this Not relevant frequency application, App. E source or in JPEEE (earthquakes) of June 1998 Large, early release License renewal 1.6E-06 per yr 1.613-05 per yr frequency (internal application, App. E events)

Medium, early License renewal 2.11E-06 per yr 2.1 E-05 per yr release frequency application, App. E (internal events)

Core damage IPE, December 4.3E-06 per yr This adjustment not frequency (internal 1993 used in this source events except intl.

floods)

Core damage IPEEE, June 1998 9.013-06 per yr Not relevant frequency (internal floods)

Core damage IPEEE, June 1998 3.8E-05 per yr Not relevant frequency (fires)

Large, early release IPE, December 9.4E-07 per yr This adjustment not frequency (internal 1993 used in this source events except intl.

floods)

Medium, early IPE, December 8.0E-07 per yr This adjustment not release frequency 1993 used in this source (internal events except intl. floods)

Risks ofpool storage ofspentfitel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 51 Table 6-3 Categories of Release to Atmosphere by Core-Damage Accidents at Pilgrim and Vermont Yankee Nuclear Plants Release Magnitude Release Timing Category Release of Cesium Category Timing of Release from Reactor Core Initiation After to Atmosphere Accident Begins High Greater than 10% Early Less than 6 hrs Medium 1% to 10%

Low 0.1% to 1% Intermediate 6 hrs to 24 hrs Low-Low 0.001% to 0.1%

Negligible Less than 0.001% Late Greater than 24 hrs Notes:

These release categories are set forth in Appendix E of the license renewal application for Vermont Yankee. In the license renewal application for Pilgrim, the same categories are used except that: (i) the Early and Intermediate categories shown in the table above are combined into one category designated as 'Early'; and (ii) the Low and Low-Low categories are combined into one category designated as 'Low'.

Risks ofpool storage ofspentfuel at Pilgrim and Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 52 Table 7-1 Potential Sabotage Events at a Spent-Fuel-Storage Pool, as Postulated in the NRC's August 1979 GEIS on Handling and Storage of Spent LWR Fuel Event Designator General Description of Event Additional Details Mode I

• Between I and 1,000 fuel

• One adversary can carry 3 assemblies undergo extensive charges, each of which can damage by high-explosive damage 4 fuel assemblies charges detonated under water

• Damage to 1,000 assemblies

° Adversaries commandeer the (i.e., by 83 adversaries) is a central control room and hold it "worst-case bounding estimate" for approx. 0.5 hr to prevent the ventilation fans from being turned off Mode 2

• Identical to Mode 1 except that, in addition, an adversary enters the ventilation building and removes or ruptures the HEPA filters Mode 3

• Identical to Mode 1 within the

• Adversaries enter the central pool building except that, in control room or ventilation addition, adversaries breach two building and turn off or disable opposite walls of the building the ventilation fans by explosives or other means Mode 4

• Identical to Mode I except that, in addition, adversaries use an additional explosive charge or other means to breach the pool liner and 5-ft-thick concrete floor of the pool Notes:

(a) Information in this table is from Appendix J of: USNRC, GenericEIS on Handling and Storageof Spent Light Water Power Reactor Fuel,NUREG-0575, August 1979.

(b) The postulated fuel damage ruptures the cladding of each rod in an affected fuel assembly, releasing "contained gases" (gap activity) to the pool water, whereupon the released gases bubble to the water surface and enter the air volume above that surface.

Risks ofpool storage of spentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by 1RSS, May 2006 Page 53 Table 7-2 Potential Modes and Instruments of Attack on a Nuclear Power Plant Mode of Attack Characteristics Present Defense Commando-style attack

• Could involve heavy Alarms, fences and lightly-weapons and sophisticated armed guards, with offsite tactics backup

- Successful attack would require substantial planning and resources Land-vehicle bomb

• Readily obtainable Vehicle barriers at entry

- Highly destructive if points to Protected Area detonated at target Anti-tank missile

• Readily obtainable None if missile launched

- Highly destructive at point from offsite of impact Commercial aircraft

• More difficult to obtain None than pre-9/1 I

- Can destroy larger, softer targets Explosive-laden smaller

• Readily obtainable None aircraft - Can destroy smaller, harder targets I0-kilotonne nuclear

• Difficult to obtain None weapon

• Assured destruction if detonated at target Notes:

This table is adapted from a table, supported by analysis and citations, in: Gordon Thompson, Robust Storage ofSpent Nuclear Fuel: A Neglected Issue ofHomeland Security, IRSS, January 2003. Later sources confirming this table include:

(a) Gordon Thompson, testimony before the California Public Utilities Commission regarding Application No. 04-02-026, 13 December 2004.

(b) Jim Wells, US Government Accountability Office, testimony before the Subcommittee on National Security, Emerging Threats and International Relations, US House Committee on Government Reform, 4 April 2006.

(c) Marvin Fertel, Nuclear Energy Institute, testimony before the Subcommittee on National Security, Emerging Threats and International Relations, US House Committee on Government Reform, 4 April 2006.

(d) Danielle Brian, Project on Government Oversight, letter to NRC chair Nils J. Diaz, 22 February 2006.

(e) National Research Council, Safety and Security of CommercialSpent Nuclear Fuel Storage: PublicReport, National Academies Press, 2006.

Risks ofpool storageofspentfuel at Pilgrimand Vermont Yankee A reportforthe Mass. A-G by IRSS, May 2006 Page 54 Table 8-1 Selected Options to Reduce Risks of Spent-Fuel-Pool Fires at the Pilgrim and Vermont Yankee Plants Option Passive Does Option Comments or Address Fire Active? Scenarios Arising From:

Malice? Other Events?

Re-equip pool with low- Passive Yes Yes

• Will substantially reduce density, open-frame racks pool inventory of radioactive material

• Will prevent auto-ignition of fuel in almost all cases Install emergency water Active Yes Yes

• Spray system must be sprays above pool highly robust

• Spraying water on overheated fuel can feed Zr-steam reaction Mix hotter (younger) and Passive Yes Yes

• Can delay or prevent colder (older) fuel in pool auto-ignition in some cases

• Will be ineffective if debris or residual water block air flow

• Can promote fire propagation to older fuel Minimize movement of Active No Yes - Can conflict with spent-fuel cask over pool (Most adoption of low-density, cases) open-frame racks Deploy air-defense system Active Yes No - Implementation requires (e.g., Sentinel and presence of US military at Phalanx) at plant plant Develop enhanced onsite Active Yes Yes

• Requires new equipment, capability for damage staff and training control

• Personnel must function in extreme environments

Risks ofpool storage ofspentfitel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by IRSS, May 2006 Page 55 Table 8-2 Selected Approaches to Protecting US Critical Infrastructure From Attack by Sub-National Groups, and Some of the Strengths and Weaknesses of these Approaches Approach Strengths Weaknesses Offensive military

• Can deter or prevent

• Can promote growth of operations internationally governments from sub-national groups hostile supporting sub-national to the USA, and build groups hostile to the USA sympathy for these groups in foreign populations

• Can be costly in terms of lives, money and national reputation International police

• Can identify and intercept

• Implementation can be cooperation within a legal potential attackers slow and/or incomplete framework

• Requires ongoing international cooperation Surveillance and control of

• Can identify and intercept

• Can destroy civil liberties, the domestic population potential attackers leading to political, social and economic decline of the nation Active defense of

• Can stop attackers before

• Can involve higher infrastructure elements they reach the target operating costs

• Requires ongoing vigilance Passive defense of

• Can allow target to

• Can involve higher capital infrastructure elements survive attack without costs damage

• Can substitute for other approaches, avoiding their costs

Risks ofpool storage ofspentfuel at.Pilgrimand Vermont Yankee A reportfor the Mass. A-G by MRSS, May 2006 Page 56 Table 8-3 Estimation of Cost to Offload Spent Fuel from Pools at the Pilgrim and Vermont Yankee Plants After 5 Years of Decay Estimation Step Pilgrim Vermont Yankee Present licensed capacity of 3,859 fuel assemblies 3,089 fuel assemblies pool Pool capacity needed for 580 fuel assemblies 368 fuel assemblies full-core discharge Anticipated av. pool 3,177 fuel assemblies 2,619 fuel assemblies inventory of spent fuel during period of license extension Av. period of exposure of 5.48 yr 3.69 yr fuel assembly in core Av. annual discharge of fuel 580/5.48 = 106 fuel 368/3.69 = 100 fuel from reactor assemblies assemblies Pool capacity needed to 106x5xl.1 = 583 fuel lOOx5xl.l = 550 fuel store fuel for 5-yr decay, assemblies assemblies incl. 10% buffer Total pool capacity needed 580 + 583 = 1,163 fuel 368 + 550 = 918 fuel for full-core discharge and assemblies assemblies 5-yr decay Fuel requiring offload if 3,177 - 583 = 2,594 fuel 2,619 - 550 = 2,069 fuel pool storage is limited to assemblies assemblies fuel undergoing 5-yr decay Capital cost to offload fuel, $54-109 million $43-87 million assuming 210 kgU per assembly and capital cost of

$100-200 per kgU for dry storage Notes:

A capital cost of $100-200 per kgU for dry storage of spent fuel is used by Robert Alvarez et al in their paper in Science and Global Security, Volume 11, 2003, pp 1-5 1.

Risks ofpool storage ofspentfuel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by 1RSS, May 2006 Page 57 Table 9-1 Provisional Estimate of the Probability of a Spent-Fuel-Pool Fire at the Pilgrim or Vermont Yankee Plant Estimation Step Pilgrim Vermont Yankee CDF (internal events) 2.8E-05 per yr 4.3E-06 + 9.OE-06 =

1.3E-05 per yr CDF (fires + earthquakes) 2.2E-05 + (5.8E-05 + 3.8E-05 + (5.8E-05 +

9.4E-05)/2 = 9.8E-05 per yr 9.4E-05)/2 = 1.1E-04 per yr CDF (internal events + fires 1.3E-04 per yr 1.2E-04 per yr

+ earthquakes)

Early release frequency 1.3E-05 + (1.3/5.8)x2.2E-05 1.7E-06 + (1.7/4.3)x(9.OE-(internal events + fires + + (1.6E-05 + 3.2E-05)/2 = 06 + 3.8E-05) + (1.6E-05 +

earthquakes) 4.2E-05 per yr 3.2E-05)/2 = 4.4E-05 per yr Conditional probability of a 0.5 0.5 pool fire, given an early (Author's assumption) (Author's assumption) release from the reactor (internal events + fires +

earthquakes)

Probability of a pool fire (4.2E-05)x0.5 = (4.4E-05)xO.5 initiated by events not 2.1E-05 per yr 2.2E-05 per yr including malice Probability of a I per 100 yr I per 100 yr maliciously-induced pool (Author's assumption) (Author's assumption) fire in the USA (99 pools)

Probability of a 1.OE-04 per yr L.OE-04 per yr maliciously-induced pool fire at this plant Total probability of a pool 2.1E-05 + 1.OE-04 2.2E-05 + 1.OE-04 =

fire at this plant 1.2E-04 per yr 1.2E-04 per yr Notes:

(a) CDF = core damage frequency (b) Estimates in the first four rows are drawn from the IPEs and IPEEEs for each plant, except that the Pilgrim internal-events CDF is drawn from: Willard Thomas et al, Pilgrim Technical EvaluationReport on the IndividualPlantExaminationFrontEndAnalysis, Science and Engineering Associates, prepared for the USNRC, 9 April 1996. Earthquake findings shown for Pilgrim are the average of the EPRI and LLNL values, and are used for both plants. The conditional probability of an early release, given core damage, is assumed to be the same for events initiated by fires and by internal events including internal flooding.

(c) The probability of a maliciously-induced pool fire in the USA is assumed to be uniformly distributed across all pools.

Risks ofpool storage ofspentfitel at Pilgrimand Vermont Yankee A reportfor the Mass. A-G by 1RSS, May 2006 Page 58 Table 9-2 Present Value of Cumulative (20-year) Economic Risk of a Potential Release of Radioactive Material Selected Characteristics of the Present (Initial) Value of Cumulative.(20-year)

Potential Release Economic Risk, for various Discount Rates (D)

Economic Cost Probability of D=7%peryr D=3%peryr D=0%peryr of the Release the Release

$100 billion 1.0E-03 per yr $1.1 billion $1.5 billion $2 billion 1.01E-04 per yr $110 million $150 million $200 million 1.0E-05 per yr $11 million $15 million $20 million 1 1.0E-06 per yr $1.1 million $1.5 million $2 million Notes:

(a) The discounted cumulative-value function is: (1-exp(-DT))/D, where T = 20.

(b) The present values shown in the table can be scaled linearly for alternative values of the economic cost or probability of the potential release.

J. t I Estimates of losses in property value. It is assumed that an area exists around the "main portion" of the plume, where potential property buyers would be concerned about residual risk. (The main portion of the plume is defined as the area where remediation or demolition takes place.) Outside the main plume, contamination would still be measurable. Lack of trust in statements by government would translate into loss in property values. All things being equal, persons would wish to live as far away from contaminated areas as possible.

Note that radioactive deposition would extend into these non-remediated areas, both from the immediate release and from resuspension in the weeks and years after the release and from subsequent demolition and remediation efforts. People would be accumulating long-term radiation doses, which government sources would say are too trivial to worry about. Expert opinion would differ on the seriousness of the long-term exposures. Confidence in government would likely drop over time based on revelations of government failings. If past patterns are followed, government leaders would early on feel compelled to downplay the true situation to prevent panic. Although it is hard to see how they could act otherwise, it is also hard to see how citizens enthusiasm for purchasing property in the vicinity of the main plume would not be weakened.

How much would property values decline? Based on expert reports filed in litigation concerning the Rocky Flats nuclear weapons facility, and the jury decision favorable to plaintiffs in that litigation (2006), I assume a 5% loss in property value for property lying within measurable contours of contamination. This is quite conservative, since the jury accepted Plaintiffs' expert assessment that residential values dropped by 7%,13 vacant land by 30%, and commercial land by 53%. For the calculations in this report, I define the main, remediated plume as a 0.24 wedge extending out to 250 miles for the 10% release and 700 miles for the -100% release.

Areas where property damage loss is assumed to take place extends outward from the plume to 1000 miles, which is where the damage calculations stop in (Beyea et al. 2004a). In addition, property in areas to the side of the plume are also expected to suffer a 5% loss in value. Because I have no firm basis for determining the distance to which property loss would extend, I have picked a ten-fold range.

At the low end, as many people outside the main plume are assume to be affected as live in the main plume. At the high end, I pick ten times as many persons.

13 The "residential" figure appears to be some sort of compromise. It's within a range reported by expert Radke's year-by-year multiple regressions for 1988-95, but it's less than the 10% that expert Hunsperger ultimately estimated. Personal commuication, 2006, Peter Nordberg, Berger and Montague.

23

) ft .

MACCS2 accounts for inhalation of resuspended material at the location where radioactivity is deposited (Chanin et al. 2004), Section 2, page 6-14. However, MACCS2 does not allow for redistribution of resuspended material to new locations. Yet, 10% of radioactivity deposited on 4 5 vegetation may be blown off in the first few weeks,1 with additional resuspension over decades,'

increased dramatically by anthropogenic activity during clean up and remediation (Schershakov 1997).

I adopt a net resuspension factor for Cesium-137 of 10% over the long term, which should be a conservative choice in this context. 16 To account for the latent cancers that would be caused by this redistribution of radioactivity, I have made the approximation that no such re-deposited material would be high enough to generate remediation. (If this assumption is violated, the number of latent cancers from redistributed radioactivity would go down, but it would then be necessary to increase clean-up costs.)

Based on wedge model calculations, I know that remediation reduces latent cancers by a factor of 10 or more. Thus, the contribution from redistributed radiation to total cancers, under the assumptions I have made, should be more than the direct contribution from the remediated plume (10%

X 10 = 100%). A more precise calculation could be obtained by running MACCS2 in a special way, even though MACCS2 does not directly handle redistributed radioactivity. (MACCS2 only allows straight-line plume segments and does not allow wind trajectories (Chanin et al. 2004), Section 5, page 1-4.) However, MACCS2 does allow multiple straight-line segments with different starting times (Chanin et al. 2004), Section 2, page 6-14. If MACCS2 was run with extra plume segments added on to the end of a standard release sequence, with varying delay times, and a total added release equal to 14 (NUREG 1975), Appendix VI. Radioiodine after weapons fallout shows very rapid decline over periods of days, some of which must be due to wind action (NCI 1997), Table 4.8. The half-life for small particles is longer, about 14 days (Prohl et al. 1995?. Resuspensionfactors in the early days after the Chernobyl accident have shown very high values, including 2.4 E-04 m" at one day after deposition (Schershakov 1997). Such a high rate could not be maintained without completely exhausting the surface concentration in a very short time. The resuspension factor has been estimated to drop as an inverse power of time in days, with an exponent of 0.5-to-1.67 (Schershakov 1997). At issue is the size of the resuspended material, because some radioactivity might deposit on relatively large particles on vegetation that are easily removed by wind.

15 Resuspension rates measured for Chernobyl radiocesium are also high (1E-08 s-1 ) (Schershakov 1997). When such a high uplift rate is totaled for periods of years, a 10% net loss is quite reasonable, although resuspension rates were measured to decrease by an order of magnitude over time (Schershakov 1997). Studies by my colleagues and I have indicated that underground material is brought to the surface by animal burrowing (Morrison et al. 1997; Smallwood et al. 1998), where it is subject to wind resuspension. Thus, movement into the soil of radiocesium does not keep it away from the surface forever. Smallwood has estimated from his measurements in California and Colorado that about 0.5 % of underground radioactivity should be brought to the surface each year by animal burrowing, including ant burrowing (Smallwood, personal communication, 1998). How relevant this number is to the East Coast is not known.

Because of lack of data on particle sizes, analysts may differ as to how much resuspended material would be in particle sizes large enough to travel outside the main plume before remediation. However, most land area would not be remediated.

In any case, it will be important for the field of contamination consequence analysis to have debates on this subject.

24

the assumed resuspension fraction times the initial release, then MACCS2 will produce as output the mathematical equivalent of resuspended material being carried in directions different from the main plume.

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Hatch M, Beyea J, Nieves J, Susser M. 1990. Cancer Near the Three Mile Island Nuclear Plant:

Radiation Emissions. Am J Epidemiol 132(3):397-412.

Hatch MC, Wallenstein S, Beyea J, Nieves JW, Susser M. 1991. Cancer rates after the Three Mile Island nuclear accident and proximity of residence to the plant. Am J Public Health 81(6):719-724.

Helton JC, Johnson JD, Rollstin JA, Shiver W, Sprung JL. 1995. Uncertainty and Sensitivity Analysis of Chronic Exposure Results with the MACCS Reactor Accident Consequence Model NUREG/CR-6134/SAND93-2370. Albuquerque: Sandia National Laboratories.

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Sensitivity and uncertainty studies of the CRAC2 computer code. Risk Anal 7(4):497-507.

Krestinina LY, Preston DL, Ostroumova EV, Degteva MO, Ron E, Vyushkova OV, et al. 2005.

Protracted radiation exposure and cancer mortality in the Techa River cohort. Radiat Res 164(5):602-611.

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Lubin JH. 1998. On the discrepancy between epidemiologic studies in individuals of lung cancer and residential radon and Cohen's ecologic regression [comment] [see comments]. Health Phys 75(1):4-10.

Lubin JH, Boice JD, Jr., Edling C, Hornung RW, Howe GR, Kunz E, et al. 1995. Lung cancer in radon-exposed miners and estimation of risk from indoor exposure. J Natl Cancer Inst 87(11):817-827.

McKay MD, Beckman RJ. 1994. A procedure for assessing uncertainty in models LA-UR 3548.

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Morrison ML, Smallwood KS, Beyea J. 1997. Monitoring the Dispersal of Contaminants by Wildlife at Nuclear Weapons and Waste Storage Facilities, USA. The Environmentalist 17:289-295.

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Nie J, Beyea J, Bonner MR, Han D, Vena JE, Rogerson P, et al. 2005. Environmental exposure to traffic polycyclic aromatic hydrocarbons (PAHs) and risk of breast cancer, American Association for Cancer Research Annual Meeting. Anaheim, April 18. Proc Amer Assoc Cancer Res: 46:[Abstract #2183].

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29

4 1 'T I Figure 1.

30

• I r Figure 2.

31

If f- ')

Figure 3. Calculated with the SECPOP 2000 computer code (Bixler et al. 2003).

Vermont Yankee cumulative population in 22.5f sectors N

-n-NNE NE

...ENE

-*- E

-- ESE SE

-- SSE 0.

0.

--o-SS SSW o SW

--5 WSW

-x-WSW

--- WNW 0 200 400 600 800 1000 1200 .NW NNW Miles MEAN 32

9 1t a Figure 4. Calculated with the SECPOP 2000 computer code (Bixler et al. 2003).

Cumulative population at Pilgrim (in 22.5 sectors)

N 70000000- -- NNE 60000000- NE ENE AA 50000000 A A YX--- E

. 40000000- AL SE Ux

• 2.Cx30000000 A - SSE AS X, x.. -

o -.X ElSS z 20000000 A A gSSw

. ,,,_.v** AWSW 10000000- A MSW 0 - .=-

""" " " " * ° " ° °" *, WNW

-10000000 -- 200 400 600 800 1000 1200 ,N N Miles NNW MEAN 33

q I- ! (

Figure 5: In the wind rose below for Pilgrim, an excess frequency beyond the 4% circle is shown for winds coming from the Southwest, which would blow out over the ocean. Ignoring return flows, such excess flows would not contribute to damage. The excess beyond the 4% circles is about 33% of the total year. Removing this excess leaves a roughly axially-symmetric flow, which matches the assumptions used in the paper by Beyea, Lyman, and von Hippel.

34

'"- 1. "

-w UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE COMMISSION In the Matter of )

)

Entergy Nuclear Operations, Inc. ) Docket No. 50-271

)

(Vermont Yankee )

Nuclear Power Station) )

.)

DECLARATION OF DR. JAN BEYEA IN SUPPORT OF MASSACHUSETTS ATTORNEY GENERAL'S CONTENTION AND PETITION FOR BACKFIT ORDER 1,Jan, Beyea, declare as follows:

1. I am senior scientist at Consulting in the Public Interest, providing scientific assistance to not-for-profits, universities, government, and injured plaintiffs.

2. In support of the Massachusetts Attorney General's request for hearing, petition to intervene and backfit petition respect to the license renewal proceeding for the Vermont Yankee nuclear power plant, I have prepared a report entitled "report to the Massachusetts Attorney General on the Potential Consequences of a Spent-Fuel Pool Fire at the Pilgrim or Vermont Yankee Nuclear Plant (May 25, 2006). In preparing my report, I reviewed the environmental report, the 1972 EIS, the FSAR, and the NRC's 1996 generic relicensing EIS. In addition, I reviewed technical documents relating to risks of spent fuel storage at this facility, which are identified in my Report. One of those documents was the report of Gordon Thompson, Ph.D.

3. The technical factual statements in my report are true and correct to the best of my knowledge, and the technical opinions expressed therein are based on my best professional judgment.

4. I am an expert regarding the consequences of both real and hypothetical nuclear accidents, as well as strategies for mitigation. I also have expertise in technical safety and environmental analysis related to nuclear facilities. My Curriculum Vitae is provided here as Attachment A.

F130M : rray wn  : Mau_ 25 200 7:17PM PA 2

5. 1 am a regular member of panels and boards of the National Research Council of the National Academy of Sciences and an advisor to the Division of Engineering and Physical Sciences.

6. After receiving my Ph.D. in nuclear physics from Columbia University, I taught environmental studies at Holy Cross College. Next, I did research at Princeton's Center For Energy and Environmental Studies modeling the consequences of nuclear accidents.

I then spent 15 years at the National Audubon Society as Senior Policy Scientist, and ultimately as Chief Scientist and Vice President

7. 1 am the author of over 100 articles and reports that span a diverse range of topics. I am a regular peer reviewer of articles for scientifiojournals. One of my specialties is geographic exposure modeling of toxic releases. My reconstruction of exposures following the TMI accident has been used in radiation epidemiologic studies. My reconstnrctions of historical exposures to traffic pollution are being used in two ongoing epidemiologic studies of breast cancer. I am a co-author of studies on risks and consequences of spent-fuel-pool fires. I presented a briefing on this work to a committee oftheNational Research Council that was studying risks of spent fuel.

8. I am prepared to testify as an expert witness on behalf of the Massachusetts Attorney GCneral with respect to the facts and opinions set forth in my Report.

I declare, under penalty of pedjuy, that the foregoing facts provided in my Declaration are true and correct to the best of my knowledge and belief, and that the opinions expressed herein are based on my b~tprofessional judgment.

Executed on 25 May 2006.

I I Jan Beyea (609-397-2370), jbeyea@cipi.com EDUCATION:

Ph.D., Columbia University, 1970 (Nuclear Physics).

B.A., Amherst College, 1962.

PROFESSIONAL EXPERIENCE:

1968 to 1970 Research Associate, Columbia University Physics Department.

1970 to 1976 Assistant Professor of Physics, Holy Cross College.

1976 to 1980 Research Staff, Ctr. for Energy & Env. Studies, Princeton Univ.

1980 to 1991 Senior Scientist, National Audubon Society, NY. NY.

1992 to 1995 Chief Scientist &Vice President, National Audubon Society, NY, NY 1996 to date Senior Scientist, Consulting in the Public Interest, Lambertville, NJ ADVISORY ACTIVITIES & APPOINTMENTS:

Current:

-Member, Committee on Alternatives to Indian Point, National Research Council

-Nat. Academies of Science, Division Advisor (Division on Engineering and Physical Sciences).

-Consultant on human exposure assessment to 1) Columbia U., 2) NCI's Radiation Division, 3) U Buffalo Dept. of Social & Preventive Med., and 4) UNC Epidemiology Dep't.

-Consultant to law firm of Berger & Montague on dose and health effects reconstruction from the Hanford and Rocky Flats nuclear weapons complexes.

-Consultant to the National Audubon Society on forest habitat research.

Past:

-Peer reviewer for the American Journal of Public Health, Environmental Health Perspectives, Environmental Toxicology and Chemistry, Bioscience, Atmospheric Chemistry and Physics, and various Boards of the National Research Council, including the Board on Radioactive Waste

-Nat. Research Council (Nat. Academies of Science), Committee on Alternatives for the Release of Solid Materials from Nuclear Regulatory Commission-Licensed Facilities, 2001-2002. Chair of technical committee.

-Member, Technical Advisory Committee on Forest Health Monitoring, Assessment and Evaluation, New York State Department of Environmental Conservation, 2001-2002

- Nat. Research Council, Comm. on DOE'S Fine Particulate Research Program, 1999

- Nat. Research Council, Board on Energy and Environmental Systems, 1993-1998.

- Nat. Research Council, Committee on "Linking Sci. & Tech. to Society's Environ. Goals."

- Board Member, Recycling Advisory Council, sponsored by the EPA, 1994-1996

- Composting Committee, Coalition of Northeastern Governors (co-chair) 1994-1996

- Member, Source Reduction Task Force, Coalition of Northeastern Governors 1991-1995

- Secretary of Energy's Advisory Board, Task Force on Economic Modeling, 1991

- National Research Council, Comm. on Alternative Energy R&D Strategies, 1990-1991

- Office of Technology Assessment, Advisor to various studies, 1984-1988 I

I Articles, reports and testimony related to nuclear radiation Issues

'Damages from a Major Release of 137Cs into the Atmosphere of the United States," (Beyea, Lyman, von Hippel), Science and Global Security, 2004: 12:125-136. (Addendum to next paper.)

"Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States," (Alvarez, Beyea, Janberg, Kang, Lyman, Macfarlane, Thompson, von Hippel), Science and Global Security, 11:1-51,2003.

"Response by the Authors to the NRC Review of 'Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States,' (Alvarez, Beyea, Janberg, Kang, Lyman, Macfarlane, Thompson, and von Hippel), Science and Global Security, 2003: 11:213-223."

"Recent developments in the scientific literature concerning radiation and disease." Report to the Public Advocate of the Nuclear Claims Tribunal of the Marshall Islands, September, 2003 "The Disposition Dilemma: Controlling the Release of Solid Materials from USNRC-Licensed Facilities," (With Richard McGee et al.), National Research Council, National Academy Press, 2002.

"The Association Between Radiation and Non-Neoplastic Thyroid Disease: a Brief Review of the Literature," Presentation at the Workshop on Targeted Screening for Thyroid and Parathyroid Disease in a Higher-Risk Population Exposed to Iodine-131, Department of Health and Human Services, Advisory Committee on Energy-Related Epidemiologic Research (ACERER), Columbia, Maryland, June 8, 2000.

"Geographic exposure modeling: A valuable extension of Geographic Information Systems for use in Environmental Epidemiology," (Beyea and Hatch), Environmental Health Perspectives 107, Supplement 1:181-190,1999 "The importance of specifying the underlying biologic model in estimating the probability of causation," (Beyea and Greenland), Health Physics 76: 269-274, 1999.

"Animal Burrowing Attributes Affecting Hazardous Waste Management," (Smallwood, Morrison, Beyea), Environmental Management, 22(6): 931-847, 1998.

"Issues in the Dose-response Analysis of the Mayak Case-Control Study," Health Physics (letter),

74(6): 726-727, 1998.

"Fallout exposures from US weapon tests: Were the doses high enough to cause autoimmune thyroid diseases?" Statement prepared for the Institute of Medicine's Committee on "Exposure of the American People to 1-131 from Nevada Atomic-Bomb Tests" "Monitoring the Dispersal of Contaminants by Wildlife at Nuclear Weapons and Waste Storage Facilities, USA." (Morrison, Smallwood, Beyea) The Environmentalist, 17: 289-295, 1997.

"Fallout Exposures from US Weapon Tests: Health Effects other than Thyroid Cancer," Before the Appropriations Committee on Labor, Health and Human Services and Education, US Senate, Oct. 1, 1997 "Plutonium distribution in the environs of Rocky Flats." (With Milton Hoenig),Health Physics (letter) 73(1), 271-272 (1997)

"Comments on 'A Reevaluation of Cancer Incidence near the Three Mile Island Nuclear Plant'

"(with Hatch and Susser), Environ Health Perspectives 105(1), 12 (1997) 2

The Use of Film Badge Data to Estimate Radioactive Releases from Nuclear Facilities (with V.

Harms), TMI Public Health Fund, August 1993.

"Nuclear Energy", (with Valerie Harms), Environment, April 1991.

"Cancer Rates after the Three Mile Island Nuclear Accident and Proximity of Residence to the Plant", (Hatch, Wallenstein, Beyea, Nieves, Susser), American Journal of Public Health, 18(6), 719-724 June 1991.

"Cancer Near the Three Mile Island Nuclear Plant: Radiation Emissions", (Hatch, Beyea, Nieves, Susser), American Journal of Epidemioloqy., 32(3), 397-412, Sept. 1990.

"Childhood Cancer Near Three Mile Island: Nuclear Plant Emissions and Background Radiation,"

(Hatch, Wallenstein, Beyea, Susser), Columbia University, New York, Sept. 1990.

Re-Estimating the Noble Gas Releases from the Three Mile Island Accident (with J. DeCicco),

TMI Public Health Fund, August 1990.

"Nuclear Power - Only as a Last Resort to Stave Off Global Warming", Forum for Applied Research and Public Poligy." Sept. 1990.

"A Realistic Agenda for Second Generation Nuclear Reactors", before the Subcommittee on Energy and the Environment of the Committee on Interior and Insular Affairs, U.S. Senate, May 10, 1990.

"Is There Any Role for Nuclear Power in Preventing Climate Disruption?", Hearing before the Subcommittee on Energy and Power, House of Representatives, Serial No. 101-17, March, 1989.

"On Potential Radiation Dosage Consequences of the Accidents that Form the Basis for the NRC Emergency Planning Rules," on behalf of the Attomey General of Massachusetts in the matter of Public Service Company of New Hampshire (Seabrook Station, Units 1 and 2) [with Steven C. Sholly, Gordon Thompson, Jennifer Leaning.] September, 1987. Also, "Sheltering at Seabrook", (with Gordon Thompson and Robert Goble), June 16, 1988.

"Responses to the Chemobyl Accident", before the Committee on Energy and Natural Resources, U. S. Senate, June 19, 1986.

Notes on Long-Range Issues in Nuclear Regulation, in "Regulation and the Nuclear Option,"

Institute for Energy Analyses, Oak Ridge Associated Universities, 1986.

Proceedings of the Workshop on Three Mile Island Dosimetry, Three Mile Island Public Health Fund, 1622 Locust Street, Phila., Pa., Dec., 1985.

Review of Dose Assessments at Three Mile Island and Recommendations for Future Research, Report to the Three Mile Island Public Health Fund, August 1984. [See also, "Author Challenges Review", Health Physics Newsletter, March, 1985; and "TMI-Six Years Later", Nuclear Medicine, 26, p.

1345, 1985.]

"Containment of a Reactor Meltdown", (with Frank von Hippel), Bulletin of Atomic Scientists, 38,

p. 52, August/September, 1982.

"Second Thoughts (about Nuclear Safety)", in Nuclear Power Both Sides, W. W. Norton and Co.

(New York, 1982).

"Some Consequences of Catastrophic Accidents at Indian Point and Their Implications for 3

Emergency Planning," testimony and cross-examination before the Nuclear Regulatory Commission's Atomic Safety and Licensing Board, on behalf of the New York State Attorney General and others, July, 1982.

"Future Prospects for Commercial Nuclear Power in the United States", before the Subcommittee on Oversight and Investigations, Committee on Interior and Insular Affairs, U. S. House of Representatives, October 23, 1981.

"Stockpiling of Potassium Iodide for the General Public as a Condition for Restart of TMI Unit No.

1", testimony and cross-examination before the Atomic Safety and Licensing Board on behalf of the Anti-Nuclear Group Representing York, April, 1981.

"Emergency Planning for Reactor Accidents", Bulletin of Atomic Scientists, 36, p. 40, December, 1980. (An earlier version of the article appeared in German as Chapter 3 in Im Ernstfall Hilflos. E. R.

Koch, Fritz Vahrenholt, editors, Keipenheuer &Witsch, Cologne, 1980.)

Some Long-Term Consequences of Hypothetical Major Releases of Radioactivity to the Atmosphere from Three Mile Island, Report to the President's Council on Environmental Quality, December, 1980.

Decontamination of Krypton 85 from Three Mile Island Nuclear Plant, (with Kendall et al), Report of the Union of Concerned Scientists to the Governor of Pennsylvania, May 15, 1980.

Some Comments on Consequences of Hypothetical Reactor Accidents at the Philippines Nuclear Power Plant (with Gordon Thompson), Audubon EPAD Report #3, April, 1980.

Nuclear Reactor Accidents: The Value of Improved Containment, (with Frank von Hippel), Center for Energy and Environmental Studies Report PU/CEES 94, Princeton University, January, 1980.

"Dispute at Indian Point", Bulletin of Atomic Scientists, 36, p. 63, May, 1980.

"Nuclear Reactors: How Safe Are They?", panel discussion sponsored by the Academy Forum of the National Academy of Sciences, Wash., D.C., May 5, 1980.

"Advice and Recommendations Concerning Changes in Reactor Design and Safety Analysis which should be Required in Light of the Accident at Three Mile Island", statement to the Nuclear Regulatory Commission concerning the proposed rulemaking hearing on degraded cores, December 29, 1980.

"The Crisis of Nuclear Energy", Subject No. 367 on William Buckley's Firing Line, P.B.S.

Television. Transcript printed by Southern Education Communications Assoc., 928 Woodrow Street, P.

0. Box 5966, Columbia, S.C., 1979.

The Effects of Releases to the Atmosphere of Radioactivity from Hypothetical Large-Scale Accidents at the Proposed Gorleben Waste Treatment Facility, report to the Government of lower Saxony, Federal Republic of Germany, as part of the Gorleben International Review, February, 1979.

"Alternatives to the Indian Point Nuclear Reactors", statement before the Environmental Protection Committee of the New York City Council, December 14, 1979. Also before the Committee, "The Impact on New York City of Reactor Accidents at Indian Point", June 11, 1979. Also "Consequences of a Catastrophic Reactor Accident", statement to the New York City Board of Health, August 12, 1976 (with Frank von Hippel).

Reactor Safety Research at the Large Consequence End of the Risk Spectrum, presented to the Experts' Meeting on Reactor Safety Research in the Federal Republic of Germany, Bonn, September 1, 4

1978.

"Emergency Planning for a Catastrophic Reactor Accident", testimony before the California Energy Resources and Development Commission, Emergency Response and Evacuation Plans Hearings, p. 171, November 4, 1978.

A Study of Some of the Consequences of Hypothetical Reactor Accidents at Barseback, report to the Swedish Energy Comm., Stockholm, DS 11978:5, 1978.

"Consequences of Catastrophic Accidents at Jamesport", testimony before the N.Y. State Board on Electric Generation Siting and the Environment in the Matter of Long Island Lighting Co. (Jamesport Nuclear Power Station), May, 1977.

"Short-Term Effects of Catastrophic Accidents on Communities Surrounding the Sundesert Nuclear Installation", testimony before the California Energy Resources and Development Commission, December 3, 1976.

"Comments on WASH-1400," Statement to the Subcommittee on Energy and the Environment, Oversight Hearings on Reactor Safety, June 11, 1976, Serial No. 94-61, p. 210.

"Upper Limit Calculations of Deaths from Nuclear Reactors," Bulletin of American Physics Sociely, 21, III 1976.

Presentations and articles related to non-radioactive pollutants "Validation And Calibration Of A Model Used To Reconstruct Historical Exposure To Polycyclic Aromatic Hydrocarbons For Use In Epidemiologic Studies." (Beyea, Hatch et al.), Environ Health Perspect 114:0003000 (2006). doi:10.1289/ehp.8659 available via http:lldx.doi.org/ [Online 13 March 20061

.Traffic Polycyclic Aromatic Hydrocarbons (PAHs), Genetic Susceptibility and Risk of Breast Cancer." (Nie, Beyea, Bonner, Han, Vena, Rogerson, Vito, Muti, Trevisan, Shields, and Freudenheim).

3rd International Congress of Developmental Origins of Health and Disease, November 16-19, 2005, Toronto.

"Residential environmental exposures and other characteristics associated with detectable PAH-DNA adducts in peripheral mononuclear cells in a population-based sample of adult females."

Shantakumar S, et al., J Expo Anal Environ Epidemiol advance online publication, 27 April 2005; doi:1 0.1 038/sj.jea.7500426.

"Emissions of polycyclic aromatic hydrocarbons from US gasoline-powered vehicles from 1960 to 1995 for use in epidemiologic studies." (Beyea, Hatch, Stellman, Gammon). Submitted.

"Environmental exposure to traffic polycyclic aromatic hydrocarbons (PAHs) and risk of breast cancer." (Nie,. Beyea, Bonner, Han, Vena, Rogerson, Freudenheim, et al.) American Association for Cancer Research Annual Meeting. Anaheim, April 18, 2005.

"Polycyclic aromatic hydrocarbons (PAH)-DNA'adducts and breast cancer: a pooled analysis,"

(Gammon MD, Sagiv SK, et al.), Archives of Environmental Health, 2004; December, in press.

"Development of a traffic model for predicting airborne PAH exposures since 1960 on Long Island, New York," Beyea, Hatch et al., Report to the National Cancer Institute and the National Institute 5

of Environmental Health Sciences for work completed under USPHS Grant U01-CNES-66572.

http://www.cipi.com/pdf/beyea2005trafficpahmodel.pdf "The Long Island Breast Cancer Study Project: Description of a multi-institutional collaboration to identify environmental risk factors for breast cancer," (Gammon et al.), Breast Cancer Res Treat, 2002:

74:235-254 "Historical reconstruction of exposure to polycyclic aromatic hydrocarbons and model validation:

examples from the Long Island Breast Cancer Study Project." (Beyea, Hatch, Stellman, Gammon et al.)

Invited paper to be presented at the Joint Conference of the International Society of Exposure Analysis and the International Society for Environmental Epidemiology, Vancouver, August 2002.

"Validation of airborne PAH exposure opportunity estimates for a large-scale epidemiologic study using soil samples collected at subjects' homes." (Stellman, Beyea, Hatch et al.) Meeting of the International Society of Exposure Analysis, poster, Charleston, 2001.

"Spatial distribution of polycyclic aromatic hydrocarbons in 500 residential soils samples collection on Long Island, NY in relation to traffic patterns." (Beyea, Stellman, Hatch et al.) 2 2 nd Annual Meeting of the Society for Environmental Toxicology and Chemistry, poster, Baltimore, Nov. 12-15, 2001.

"Potential Toxic and Carcinogenic Chemical Contaminants in Source-Separated Municipal Solid Waste Composts: Review of Available Data and Recommendations," (with Jim Cook), Toxicological and Environmental Chemistry, 67:27-69, 1998.

Articles and reports related to urban and community design Audubon House: Building the Environmentally Responsible, Enerqy-Efficient Office, John Wiley &

Sons, NY, 1994 (with Shaw, Baumgarten, Lee, Croxton, Childs)

"Audubon House," Nat. Inst. of Standards and Technology Special Publication 863, Proceedings of the U.S. Green Building Conference, 1994.

"The Minnesota Source-Separated Composting Project," Interim Report (with rest of project team), July 1995.

"A Vision for Composting," in Proceedings of the 6th Annual Waste Reduction, Prevention, Recycling, and Composting Symposium, Solid Waste Association of North America, Feb. 27- March 1, 1995.

"The Santa Barbara County Pilot Waste Collection Project," (with rest of project team), April 1994.

"Wet Bag Composting Trial Yields Promising Results", (with Lauren DeChant, Margaret Conditt, and Bruce Jones), Biocycle, April 1993.

"Composting Plus Recycling Equals 70 Percent Diversion", (with Lauren DeChant, Bruce Jones, Margaret Conditt), Biocycle, May 1992.

The Power of Composting, The Power of Partnership (with W. Greggs), Proceedings of the Solid Waste Association of North America, August 1993.

Wet Bag Composting Report (with M. Conditt, et al), Audubon and Procter & Gamble Report, September 1993.

6

t "The Power of Composting, The Power of Partnership", speeches for the National Recycling Confernece, Oct. 1993, GMA/FMI environmental conference, March 1993, the U.S. Conference of Mayors, April 1993, and the Biocycle conference, May 1993.

"Paper Versus Plastic" in The Plastic Waste Primer, The League of Women Voters/Handbook for Citizens, Lyons & Burford, Oct. 1992.

The Audubon Proposal for Solid Waste Management in Jefferson County and the City of Louisville, Kentucky, Dec. 1991. Also Review of Proposed Resource Recovery Agreement Between the City of Louisville and Louisville Energy and Environment.

Solid Solutions for Solid Waste, NAS Guidebook for the Community Solid Waste Management Program, (Beyea, Bolze, Lee, Lathan, Hansell), (draft).

"The Great Paper Versus Plastic Debate", Audubon Activist, p. 5, March/April, 1989.

Plastics vs. Paper: Some Environmental Considerations, Audubon Report, 1989.

"Indoor Air Pollution", Bulletin of Atomic Scientists, 37, p. 63, Feb., 1981.

Articles and reports related to energy efficiency "Green Grocers Mean Energy-Efficient grocers," Store Equipment & Design (with Alys Campaign), April 1995.

"Global Warming", (with Eric Fischer), before the Public Service Commission of Wisconsin, Jan.

13,1992.

Energy Policy and Global Warming", in Global Climate Change and Life on Eath. Chapman &

Hall, New York, 1991.

"The C02 Diet for a Greenhouse Planet: Assessing Individual Actions for Slowing Global Warming." In Energy Efficiency and the Environment: Forging the Link. American Council for an Energy-Efficient Economy; Washington, DC. (Also: "The C02 Diet for a Greenhouse Planet: A Citizen's Guide for Slowing Global Warming." National Audubon Society Report). 1991; and "The Audubon Activist Carbon Dioxide Diet", Audubon Activist. p. 8-9, January/February, 1990.) (All with with DeCicco, Cook, and Bolze.)

Confronting Climate Change: Strategies for Energy Research and Development, (Morrison, Beyea, et al), National Research Council, National Academy Press, Washington D.C., Oct. 1990.

"U.S. Appliance Efficiency Standards", (Rollin and Beyea), Enercy Po.icy, 13, p. 425, 1985.

The Audubon Energy Plan, (Beyea et al), 2nd Ed., July 1984 (1st Ed., 1981) [See also, Intro. to Special Issue on Legal Issues Arising From The Audubon Energy Plan 1984, Columbia Journal of Environmental Law, 11 p. 251, 1986].

"Dealing with Uncertainties in Projections of Electricity Consumption", before the Committee on Energy and Natural Resources, U. S. Senate, July 25, 1985.

"Computer Modeling for Energy Policy Analysis", (Medsker, Beyea, and Lyons), Proceedings of the 15th Annual Modeling and Simulation Conference, Pittsburgh, PA, 15, part 3, p. 1111, 1984.

"Comments on Energy Forecasting", material submitted for the record at Hearings before the 7

Subcommittee on Oversight and Investigations of the House Committee on Science and Technology; Committee Print No. 14, June 1-2, 1981.

"Locating and Eliminating Obscure but Major Energy Losses in Residential Housing", (Harrje, Duff, and Beyea), ASHRAE Transactions, 85, Part II, 1979. (Winner of ASHRAE outstanding paper award.)

"Attic Heat Loss and Conservation Policy", (Dutt, Beyea, and Sinden). ASME Technology and Society Division Paper 78-TS-5, Houston, Texas, 1978.

"Critical Significance of Attics and Basements in the Energy Balance of Twin Rivers Townhouses", (Beyea et al), Enegy and Buildings, Vol. 1(1977), p. 261. Also Chapter 3 of Saving Energy in the Home, Ballinger, 1978.

"The Two-Resistance Model for Attic Heat Flow: Implications for Conservation Policy", (Woteki, Dutt, Beyea), Energy-The Intl. Journal, 3, 657, 1978.

"Comments on the Proposed FTC Trade Regulation Rule on Labeling and Advertising of Thermal Insulation", (Beyea and Dutt), before the Federal Trade Commission, 1978.

Articles, reports and speeches related to watershed and river protection "Long-Term Threats to Canada's James Bay from Hydroelectric Development", Information North, Arctic Institute of North America, Alberta, Canada, Sept. 1990.

Long-Term Threats to Canada's James Bay From Human Development, (Rosenthal and Beyea),

Audubon EPAD Report #29, July, 1989.

"The New York Connection to Hydro-Quebec's James Bay Project", speech given for the NYC Bar Association/The Americas Society Debate, January 1992.

National Audubon Society's Direct Testimony Before the Vermont Public Service Board on the Environmental Impacts of the Proposed Contract with Hydro-Quebec on Vermont Wildlife, (with Susan Drennan), December, 1989.

"The Citizens' Acid Rain Monitoring Network", (Bolze and Beyea), Environmental Science &

Technology, 23(6), June, 1989.

"Citizens' Acid Rain Monitoring Network", (Bolze, Martyr, and Beyea), presented at a National Workshop on 'The Role of Citizen Volunteers in Environmental Monitoring", held at the University of Rhode Island, May, 1988.

Threats to Wildlife and the Platte River, (Safina, Rosenbluth, Pustmueller, Strom, Klataske, Lee, and Beyea), Audubon EPAD Report #33, March, 1989.

Articles and reports on resolving scientific uncertainties through partnership "Guidelines to Sustain Biodiversity in Northeastern Pennsylvania Forests", (with T.S.

Fredericksen, W. Hoffman, B.N. Johnson, and M.B. Lester), A Partnership Project with the Procter &

Gamble Co., Poster at Mid-Atlantic Highlands Assessment Conference, Davis, WVA. October, 1995.

8

Report To The Massachusetts Attorney General On The Potential Consequences Of A Spent-Fuel-Pool Fire At The Pilgrim Or Vermont Yankee Nuclear Plant.

Jan Beyea, Ph.D.

May 25, 2006 Consulting in the Public Interest 53 Clinton Street Lambertville, NJ 08530 I

Personal Background. I am a nuclear physicist who has studied the consequences of both real and hypothetical nuclear accidents, as well as strategies for mitigation. I am a regular member of panels and boards of the National Research Council of the National Academy of Sciences and an advisor to the Division of Engineering and Physical Sciences. After receiving my Ph.D. in nuclear physics from Columbia University, I taught environmental studies at Holy Cross College. Next, I did research at Princeton's Center For Energy and Environmental Studies modeling the consequences of nuclear accidents. I then spent 15 years at the National Audubon Society as Senior Policy Scientist, and ultimately as Chief Scientist and Vice President. Currently, I am senior scientist at Consulting in the Public Interest, providing scientific assistance to not-for-profits, universities, government, and injured plaintiffs.

I am the author of over 100 articles and reports that span a diverse range of topics. I am a regular peer reviewer of articles for scientific journals. One of my specialties is geographic exposure modeling of toxic releases (Beyea and Hatch 1999). My reconstruction of exposures following the TMI accident has been used in radiation epidemiologic studies (Hatch et al. 1990; Hatch et al. 1991).

My reconstructions of historical exposures to traffic pollution (Beyea et al.; Beyea et al. 2005) are being used in two ongoing epidemiologic studies of breast cancer (Gammon et al. 2002), (Nie et al.

2005). I am a co-author of studies on risks and consequences of spent-fuel-pool fires (Alvarez et al.

2003a), (Beyea et al. 2004a), (Beyea 1979). I presented a briefing on this work to a committee of the National Research Council that was studying risks of spent fuel.

Introduction I have been asked by the Office of the Attorney General, Commonwealth of Massachusetts, to consider the consequences of releases of radioactivity from spent-fuel-pool fires at the Pilgrim and Vermont Yankee nuclear plants, as part of a relicensing proceeding. In my report I consider important new information on the consequences of releases of radioactivity, in general, and spent-fuel-pool fires, in particular, that was not available to the analysts who prepared earlier documents that are relevant to these proceedings. For example, this new information, which deals with damage costs and radiation risks, was not available prior to the publication of the Environmental Reports for Pilgrim and Vermont Yankee; it was not available prior to the publication of the generic relicensing environmental impact statement (NUREG 1996); and, some of it was not available prior to the filing of Entergy's license renewal application. Consequently, these earlier documents are incomplete from the scientific perspective.

2

I have addressed the consequences of releases from spent-fuel pools prior to these proceedings (Alvarez et al. 2003a), (Beyea et al. 2004a), (Beyea 1979), in some cases in collaboration with Gordon Thompson, Ph.D., who is filing a separate report in these proceedings. The work we have done has led to a study of the National Research Council' and has generated considerable debate and commentary (Alvarez et al. 2003b; Alvarez et al. 2003c; Beyea et al. 2004b)). We have revised our calculations to account for criticisms we thought were valid and easily addressable. In particular, Edwin Lyman, Frank von Hippel and I, in our most recent published work (Beyea et al. 2004a), which forms the backbone of this report on Pilgrim and Vermont Yankee, have specifically responded to criticisms by NRC staff concerning the use of constant population densities around nuclear plants (Alvarez et al.

2003c). In this report, I have addressed additional limitations that raised concerns about our earlier work in some circles. Although critiques of our independent work indicate that there are differences among analysts on the quantity of radioactivity that might be released in a spent-fuel-pool fire and the probability of such releases, there is a consensus among the technical community that this problem needs to be addressed.' 3 For my report, I have considered releases of 10% and 100% of the pool inventory, using methodologies outlined in (Alvarez et al. 2003a) and (Beyea et al. 2004a). I have also provided 1 For a discussion of the relationship between our study and the National Research Council's report (NatRC 2005), see remarks of Kevin Crowley before the Council on Foreign Relations (Crowley 2005).

2 Allan Benjamin, lead author of the original 1979 spent-fuel paper from Sandia Laboratory, was a reviewer of our 2003 paper in SG&S. He provided a public commentary on it, in which he stated, "In summary, the authors are to be commended for identifying a problem that needs to be addressed, and for scoping the boundaries of that problem. However, they fall short of demonstrating that their proposed solution is cost effective or that it is optimal." (Benjamin 2003). Whether or not we "fell short" in demonstrating cost effectiveness or optimality is not the issue at this stage in the relicensing proceedings.

3 It was in 2005, after the relicensing GEIS was completed, that the National Research Council (NatRC) released its study on risks of spent-fuel-pool fires.

"The committee judges that successful terrorist attacks on spent fuel pools, though difficult, are possible.

... If an attack leads to a propagating zirconium cladding fire, it could result in the release of large amounts of radioactive material.

... Additional analyses are needed to understand more fully the vulnerabilities and consequences of events that could lead to propagating zirconium cladding fires.

... it appears to be feasible to reduce the likelihood of a zirconium cladding fire by rearranging spent fuel assemblies in the pool and making provision for water-spray systems that would be able to cool the fuel, even it the pool or overlying building were severely damaged.

...Dry cask storage has inherent security advantages over spent fuel pool storage, but it can only be used to store older spent fuel.

The committee judges, however, that further engineering analyses and cost-benefit studies would be needed before decisions on this and other mitigative measures are taken." (NatRC 2005)

I note that such engineering analyses and cost-benefit studies have not been published by the applicants.

3

additional calculations that a) fill in some gaps left in earlier work, and b) take into account new information that has recently become available. 10% and 100% are the release fractions recommended for consideration by Gordon Thompson in his report. I have read his report and find it consistent with my knowledge of this field. These release fractions match earlier published work by Thompson, myself, and co-authors (Alvarez et al. 2003a), (Beyea et al. 2004a). They also are consistent in order of magnitude with values considered appropriate by the analyst who did the original work on releases from spent-fuel pools. 4 In addition to a 10% and 100% release fraction, I have also considered (briefly) a smaller release. I have presented general formulas that can be used to estimate consequences for a wide range of releases, other than 10% or 100%.

Thompson finds the inventory of Cesium-137 to be somewhat higher at Pilgrim and Vermont Yankee than the default inventory for a generic reactor considered in (Alvarez et al. 2003a). The differences are not major. I have reviewed Thompson's analysis and find his values reasonable for me to use.

Thompson has estimated the heat rate of a spent-fuel-pool fire to be higher at Pilgrim and Vermont Yankee than estimated for a generic spent-fuel pool in (Alvarez et al. 2003a). The difference in resulting plume rise is within one standard deviation for plume rise, using standard formulas, so it has not been necessary for me to modify my calculations with respect to plume rise.

Before submitting a report on consequences of a 10% and 100% release, I have made an independent assessment to assure myself that such releases are probable enough to be more than a mathematical exercise. I have already noted that many analysts have found that the generic, spent-fuel-pool problem needs to be addressed. In addition, I have reviewed the treatment of release probabilities in the companion report of Gordon Thompson, Ph.D. I find his analysis reasonable and conservative. I am certainly comfortable relying on his plant-specific probability numbers for this proceeding. I note that his estimate of the probability of a release caused by a malicious act increases his total probability estimate by only a factor of 6. A factor of 6 increase is modest, given the ingenuity that terrorists have shown in the past. Thompson's plant-specific numbers are consistent with generic probability analyses that were part of a scoping cost-benefit analysis that my colleagues and I made in 2003 (Alvarez et al.

4 Allan Benjamin, lead author of the original 1979 paper from Sandia Laboratory, was a reviewer of our 2003 paper in SG&S. He provided a public commentary on it, in which he stated,. "Although there is clear evidence that some of the fuel would melt in such a situation, we don't know how much. Since we don't, it is conservative and appropriate to assume that a large fraction of the fission product inventory could become released to the environment. Whether that fraction is 0.20 or 1.00 doesn't change the fact that the release would be unacceptable." (Benjamin 2003) 4

2003a). Our analysis suggests that even using older probability numbers, and without considering threats of terrorism or new data on radiation risks to be discussed later, moving older fuel to dry cask storage is nearly cost-effective.5 The Nuclear Regulatory Commission's response to the issues raised by the report of the National Research Council (NatRC 2005) and our paper in Science and Global Security (SG&S)(Alvarez et al. 2003a) is discussed in (Dorman 2005). The NRC does not appear to be addressing the scenarios of most concern to me, such as those addressed by Thompson in his report for Pilgrim and Vermont Yankee. The Commission essentially sees the spent-fuel pool problem as a non-issue that is diverting resources from more important areas. However, the basis for the Commission's overall judgment is secret, presenting a challenge in relicensing proceedings to independent scientists like myself, who are not allowed to review the secret analysis. Should I simply accept the Commission's judgment without review and remain silent to avoid any chance of providing useful information to terrorists? The problem with such a stance is that I do not believe the Commission (or any government agency) can best protect the public against terrorism in the absence of vigorous pressure from, and critical analysis by, a range of stakeholders. It would be irresponsible to say nothing, but equally irresponsible to say too much. I hope the balance I have struck in this report is the right one. I certainly conclude from all of the analysis carried out, both by me, Thompson, and others, and the lack of response by the NRC to date, that computing the consequences of large releases of Cesium-137 in regulatory proceedings is responsible and in the public interest.

Another reason that I find it important to make consequence calculations in these proceedings is that the NRC's own Inspector General has observed that the NRC appears to have informally established an unreasonably high burden of requiring absolute proof of a safety problem (IG 2003).

Considerable evidence is available that a correspondingly high barrier has been set for alternatives to pool storage at reactors, based on comments by NRC staff on our 2003 paper and by my reading of (Dorman 2005). Thus, independent analysts may be the only vehicle for computing state-of-the-art consequences, if the NRC is reluctant to commission such calculations or require applicants to make them.

Consequences of a release. The first realistic study of the economic and land use consequences of 5 The approach I took for our 2003 report, when it came to dealing with terrorism, was to think of scenarios that a terrorist group might come up with using the technical means I thought would be reasonably available to them. Since at least one of those generic scenarios I came up with seemed plausible, I considered at the time, and still do, that we need to understand the consequences of spent-fuel-pool fires.

5

i releases of long-lived radioactivity that tried to go beyond bounding calculations was published in 1996 (Chanin and Murfin 1996). This work appeared in the same year of publication of the relicensing GEIS (NUREG 1996), so would not likely have been considered in the GEIS. More recently, in 2003 and 2004, estimates of the long-term health consequences of releases from spent-fuel fires were published by our group of independent analysts, as noted above. Some NRC Commissioners have referred to staff analyses refuting our published results, but such analyses have never been made public, as far as I am aware. If the new staff analysis does exist, it was also prepared after the GEIS and so should be incorporated into the EIS for Pilgrim and Vermont Yankee. The staff analysis that has been published is sobering and only applies specifically to decommissioning (Collins and Hubbard 2001).

For this report, components of damage costs not previously considered at other sites have been included. For instance, new damage cost and latent cancer calculations have been made to extend the work by Beyea, Lyman, and von Hippel to areas contaminated by resuspension. Results from "wedge model" calculations (discussed below) have been used for this purpose. Loss of property value outside remediated areas have also been considered, again with reliance on the wedge model. Approximate correction has been made for wind-rose effects, something that was not done in (Beyea et al. 2004a).

In addition, I have made cost and latent cancer estimates, assuming that the latest radiation mortality studies are used in the calculations. As for the standard components of damage calculations, I have scaled, interpolated or extrapolated from values computed for other sites as reported in (Beyea et al.

2004a). Since the MACCS2 model was run in the paper by Beyea, Lyman, and von Hippel, with the parameter values listed there, the results in this report on Pilgrim and Vermont Yankee are based on the MACCS2 model.

The models included in the MACCS2 code are based largely on methodologies originally developed for the 1975 Reactor Safety Study (NUREG 1975); as refined in the CRAC2 code (Kocher et al. 1987; Ritchie et al. 1984). See (Young and Chanin 1996). A simpler approach to consequence analysis (wedge model) was developed by an American Physical Society group that reviewed the Reactor Safety Study (APS 1975). The wedge-model provides quick estimates of consequences that usually gives similar results to more detailed models, such as MACCS2, provided one uses appropriate effective parameters. The wedge model may underestimate acute consequences in situations where changing weather classes dominates health effects, but that is not a major issue for releases of cesium-137, where the risk is from long-term exposure.

Details of the calculations made for this report are given in Appendix I. Tables with 6

A quantitative results appear in a subsequent section. Reliance on output from the MACCS2 computer code or the wedge model to estimate consequences from releases of Cesium-137 in this report does not necessarily imply endorsement of the use of these methodologies in other contexts, nor endorsements of the parameter sets that applicants or others may use with them. All models have strengths and weaknesses that must not be forgotten by modelers. MACCS2 does not appear to have undergone extensive field validation (Young and Chanin 1997), but sensitivity studies have been undertaken (Helton et al. 1995; McKay and Beckman 1994), (Neymotin 1994) and a large number of expert elicitations have been carried out that provide uncertainty distribution for input parameters (Goossens et al. 1997; Harper et al. 1993; Little et al. 1997; USNRC 1995). The model has been used in a limited number of peer-reviewed publications. Edwin Lyman, who ran the MACCS2 code for (Beyea et al.

2004a) has probably the greatest number of peer-reviewed papers using MACCS2.

For late health effects, which are of interest in this report, the deposition velocity has been found to be a major parameter affecting MACCS results (Helton et al. 1995). Because the uncertainty distribution for deposition velocity is quite broad (USNRC 1995), the variance in the MACCS2 predictions for cancers (and damage costs) could be large. When possible, I prefer to rely on exposure models that have been tested against field data, such as those I have developed in recent years (Beyea et al.). However, by relying on results from MACCS2 in these proceedings with respect to consequences from releases of Cesium-137, I hope to avoid distracting debate over models.

In the next section, I present results of consequence calculations using standard cancer risk coefficients. In subsequent sections, I discuss major new studies on cancer risks from radiation that suggest the risk coefficients used in most versions of MACCS2 are way too low. I then present consequence calculations using higher cancer coefficients and discuss some of the implications for cost benefit analyses. Finally, I discuss some new developments in dispersion modeling at coastal sites. I suggest that the applicant at Pilgrim should undertake sensitivity studies using appropriate computer codes to see if this new knowledge of meteorology modifies cost-benefit computations.

Quantitative damage estimates for releases from Pilgrim and Vermont Yankee, assuming standard cancer risk coefficients:

This section presents a subset of consequence estimates for hypothetical releases of Cesium-137 from spent-fuel pools at Pilgrim and Vermont Yankee. Estimates are presented for economic costs and latent cancers. Variance in the estimates are not considered for the contention phase. Details of the 7

estimates are given in the Table footnotes and in Appendix I. Political, psychological, and social impacts of hypothetical releases are not considered, although they could obviously be significant. For instance, there appears to exist a "radiation syndrome" that affects a subset of exposed populations, causing debilitating psychiatric symptoms (Vyner 1983). Psychological effects of radiation disasters are expected to be most serious for children (CEH 2003).

Releases of 10% and -100% of the radiocesium in the spent-fuel pools at both Pilgrim and Vermont Yankee are considered. Results are presented in this section using the standard risk coefficients assumed in (Beyea et al. 2004a). Releases lower than 10% of the Cesium-137 inventory, even releases too low to justify remediation, could have costs associated with loss in property value in the range of 10 to 100 billion dollars.

The damage estimates shown in the Tables are much less than the GDP of the US, which is about 12 trillion per year. However, some of the numbers exceed the annual payment on the national debt, which is about 350 billion dollars per year, indicating that government borrowing to cover the damage payments from a spent-fuel-pool fire could represent a major perturbation on the economy.

Thus, significant macroeconomic effects could be expected depending on the state of the economy at the time of any hypothetical release. The regional impacts would be expected to be the most serious.

Estimating such effects are beyond the scope of this report.

The Tables include numbers in some cells to 3-significant figures. This does not imply any comparable level of accuracy.

8

Table 1. Cost estimatesfor a release oflO% ofspent-fuel pool inventory ofradioactive Cesium-137 assuming no change in cancer risk coefficient (billionsof dollars)

Category Pilgrim Vermont Yankee Comment Direct costsa) 49 39 Indirect administrative 49 39 costsb)

Loss in property values 7-74 9-87 adjacent to treated areasc)

Costs associated with  ?? '> Particularly important cleanup or demolition of for Pilgrim, with its downtown business and proximity to Boston commercial districts, heavy industrial areas, or high-rise apartment buildings.d)

Total > 105-171 > 87-165 a) As estimated from computations with MACCS2 at comparable sites with the parameters given in (Beyea et al. 2004a). Reduction by 1/3 rd to account for wind rose effects.

b) Based on Chanin and Murfin. "We believe.., that it might be reasonable to double the cost estimates provided [here] in order to account for indirect costs." (Chanin and Murfin 1996), p. 6-3.

The factor might not be as great in the current case, however, because of economies of scale. We assume that litigation costs offset any economies of scale.

c) Assumes 5% loss in property value for an area surrounding the plume that includes 1 to 10 times as many persons as are in the (0.24 radian) plume extending out to 250 miles (see Appendix I). A similar 5% loss in property value is assumed in the plume from 250-1000 miles. $132,000 in property value assumed per capita (Beyea et al. 2004a). Although not included in this total for the contention phase, loss in property value upon sale by government of remediated property should be included here. MACCS2 assumes no such loss.

d) We have not attempted an estimate for this category in the contention phase.

9

14 1 Table 2. Cost estimatesfor a release of -100% ofspent-fuelpool inventory of Cs-137 assuming no increasein cancer risk coefficient (billionsof dollars)

Category Pilgrim Vermont Yankee Comment Direct costsa) 163 173 Indirect administrative 163 173 costsb)

Loss in property values16-162 17-172 adjacent to treated areasc)

Costs associated with  ??  ?? Particularly important cleanup or demolition of for Pilgrim, with its downtown business and proximity to Boston commercial districts, heavy industrial areas, or high-rise apartment buildings.d)

Total > 342-488 > 364-518 a) As estimated from computations with MACCS2 at comparable sites with the parameters given in (Beyea et al. 2004a). Figures reduced by 1/ 3 rd to account for wind rose effects.

b) Based on Chanin and Murfin. "We believe.., that it might be reasonable to double the cost estimates provided [here] in order to account for indirect costs." (Chanin and Murfin 1996), p. 6-3.

The factor might not be as great in the current case, however, because of economies of scale. We assume that litigation costs offset the economies of scale.

c) Assumes 5% loss in property value for an area including 1 to 10 times as many persons as are in a 0.24 radian plume extending out to 700 miles (see text). A similar 5% loss in property value is assumed in the plume from 700-1000 miles. $132,000 in property value assumed per capita (Beyea et al. 2004a). Although not included in this total for the contention phase, loss in property value upon sale by government of remediated property should be included here. MACCS2 assumes no such loss.

d) We have not attempted an estimate for this category in the contention phase.

10

Note that the latent cancer estimates in Table 3, below, are lower limits, because they only include the cancers from Cesium-137. This approximation ignores shorter isotopes in the fresh fuel in the pool, especially Cesium-134 (Benjamin 2003).

Table 3. Estimatesfor latentcancersfollowing releasesfrom the spent-fuelpools at eitherPilgrim or Vermont Yankee (assumingno increasein cancerrisk number)

Category 10% release -100% release Latent cancers in main plume 1300 4000 path from residual contaminationa)

Latent cancers from deposited 1300 4000 resuspensionb)

Total 2,700 8,000 a) Based on typical numbers for plants analyzed in (Beyea et al. 2004a). Figures reduced by 1/3 rd to account for wind rose effects. Cancers in the direct plume are reduced by more than a factor often from decontamination and deconstruction.

b) Assumes 10% resuspension and redistribution of deposited Cesium-137 resulting from a) wind removal in the first few weeks, and b) remediation/demolition efforts over successive years. It is possible that even the resuspended Cesium would produce concentrations high enough to justify remediation, with a corresponding reduction in projected cancers. However, clean-up costs would be increased.

I have not been able to incorporate new understanding of the flow of air over and around the New England Coastline that has been achieved in recent years. Still, this new knowledge should be taken into account in EISs for coastal facilities. Releases from Pilgrim headed initially out to sea will remain tightly concentrated due to reduced turbulence until winds blow the puffs back over land (Zagar et al.), (Angevine et al. 2006). This can lead to hot spots of radioactivity in unexpected locations (Angevine et al. 2004). Dismissing radioactivity blowing out to sea is inappropriate. Reduction of turbulence on transport from Pilgrim across the water to Boston should also be studied. Although incorporating such meteorological understanding into a PSA or equivalent at Pilgrim would not be likely to make more that a factor of two difference in risk, the change could bring more SAMAs into play and would be significant in an absolute sense, when combined with the increase arising from incorporation of new values of radiation dose conversion coefficients (discussed below). The program 11

CALPUFF (Scire et al. 2000) has the capability to account for reduced turbulence over ocean water and could be used in sensitivity studies to see how important the phenomenon is at Pilgrim.

New cancer risk coefficients There have been increases in the value of the cancer risk assigned to low doses of radiation that should be taken into account in EISs. These increases have been steady since 1972,6 which makes the original EISs out of date. In addition, there has been a marked increase in the value of the cancer mortality risk per unit of radiation at low doses (2-to-3 rem average) as a result of recent studies published on a) radiation workers (Cardis et al. 2005) and b) the Techa River cohort (Krestinina et al. 2005). Both studies give similar values for low dose, protracted exposure, namely about 1 cancer death per Sievert (100 rem).

Worker study: The average dose for the workers was 2-rem. The authors of this large, international study of radiation workers included major figures in the field of radiation studies. The authors state, "On the basis of these estimates, 1-2% of deaths from cancer among workers in this cohort may be attributable to radiation." Although it can be misleading to interpret epidemiologic data in this way (Beyea and Greenland 1999), because it implies to non-experts a single-cause model of cancer, there is no doubt that a 1-2% increase in cancer mortality for a worker population is unusually high.

Techa River Cohort: The results for the Techa River cohort are equally striking, showing a strong linear effect down to a few rads. The average dose was 3 rads. The authors, who once again include major figures in the field of radiation studies, state: "It is estimated that about 2.5% of the solid cancer deaths...are associated with the radiation exposure." As in the worker population, an increase in solid cancer deaths of 2.5% from a dose of 3 rads is extraordinarily high compared to past estimates.

Such high risk coefficients imply that background radiation itself must increase cancer mortality by 3-5%.7 (It has long been known that background radon concentrations may well increase lung cancer rates by 10% or more (Lubin et al. 1995), (Darby et al. 2005).) Critics of studies like those by 6 For instance, there was a large increase in the risk coefficients estimated between the 1980 BEIR III report and the 1990 BEIR V report. See Table 4-4 of (National Research Council 1990), where the lifetime risk estimates increased by a factor of 4.6-19, depending on the risk model.

7 Assuming 0.1 rem per year background, which ignores the "equivalent" dose to the lung from radon. It is more difficult to compare rates of lung cancer, because the interaction of smoking and radiation has been found to lie between a linear and relative model. Therefore, such interactions must be taken into account, before drawing conclusions about area-wide differences, or lack of differences, in lung cancer rates.

12

Cardis et al. and by Krestinina et al. argue that such big effects, if they were real, should show up in cancer statistics in places like Colorado, where background radiation is high, when compared to areas of the country where background radiation is lower. However, crude statistical analysis that does not adjust for covariates at an individual level is unlikely to be very reliable (Lubin 1998). Also, there is an issue of the confounding effect of hypoxia (Weinberg et al. 1987). Hypoxia also varies with altitude.

Because the average dose in these two new studies is so low and so close to background radiation dose, there is no way to escape the linear non-threshold model. Even were a hypothetical hormesis effect to lead to a minimum risk at background levels (5 rem lifetime dose), the risk has to rise again after another 2-3 rem dose, based on the studies by Cardis et al. and Krestinina et al.

Could the increased risk numbers be due to a systematic underestimate or underreporting of doses? Random errors in doses would tend, in most cases, to reduce the strength of associations (Carroll et al. 1998), (Thomas et al. 1993). On the other hand, if dose errors were not random, but were proportionately underestimated or proportionately underreported in the worker studies and the Techa River cohort, then the risk coefficients could be inflated. For this to happen in both studies would be a coincidence. And in the radiation worker study, the results for Hanford do not support the missing-dose hypothesis, even though we know the neutron doses were likely underreported at Hanford (CohenAssociates 2005). In fact, the cancer risk numbers at Hanford were lower than average, not higher (Cardis et al. 2005). Finally, should the Techa River cohort dose estimates be too low that would mean that modem dose reconstruction techniques are underestimating doses, suggesting that other modem dose estimation techniques, such as those used in MACCS2 (Chanin and Young 1997),

the standard NRC consequence code, could well be too low. In that case, an upward adjustment of doses would be required, if the risk coefficients were kept the same. Certainly, from a public health point of view, the arguments are strong for making use of the new risk coefficients, one way or another, with programs like MACCS2 and other consequence codes.

Recent press reports around the anniversary of the Chemobyl accident seemed to suggest that effects of radiation doses were lower than expected. Not at all. The "new" estimates of 4,000 projected fatalities were merely a re-interpretation of a study from the 1990s. No longer were 5,000 projected cancers outside the most highly contaminated regions counted. Also, another 7,000 cancers projected to occur in Europe were not noted by the press (Cardis et al. 2006). A summary of all of these estimates can be found in (Cardis et al. 2006). Were the new risk coefficients discussed earlier applied to the population dose estimates, the projected numbers of fatalities from the Chernobyl releases would 13

climb much higher.

The confusion over the Chernobyl numbers appears to be traceable to a typo in a highly publicized IAEA report (Forum 2005) that relied on a WHO report for its cancer numbers (WHO 2005). TheWHO report stated that the "Expert Group" concluded that there may be up to 4 000 additional cancer deaths among the three highest exposed groups over their lifetime (emphasis added).

This was translated in the IAEA report to, "The total number of people that could have died or could die in the future due to Chomobyl originated exposure over the lifetime of emergency workers and residents of most contaminated areas is estimated to be around 4 000." (Emphasis added.) In fact, in 8

my view, the last clause should have referred to "residents of the most contaminated areas..."

Impact of new cancer risks. As a result of these two radiation studies, all probabilistic safety analyses prepared prior to them need to be revisited. These new studies should change the threshold for adoption of severe accident mitigation alternatives (SAMA). For instance, the current Environmental Report for Pilgrim assigns a value of $2,000 per person rem in deciding whether a proposed SAMA is cost effective. According to the results of the study by Cardis et al., $2,000 per rem implies a valuation of

$200,000 per cancer death before discounting, which is way to low.9 The same low valuation of life would arise from use of the risk numbers derived from the Techa River cohort (Krestinina et al. 2005).

As a result, the SAMA analyses prepared for the Pilgrim and Vermont Yankee facilities need to be redone, even without inclusion of spent-fuel-pool fires as a risk to be addressed. Presumably, a number of additional SAMAs that were previously rejected by the applicant's methodology will now become cost effective. In addition to affecting the existing SAMA calculations, the new cancer risk coefficients make the consideration in an EIS of mitigation measures for spent-fuel-pool fires especially important.

In addition to providing motivation for a reanalysis of past PSAs and SAMA thresholds, the results of these new epidemiologic studies throw into doubt the entire basis of the NRC culture, which maintains thatthe linear non-threshold theory (LNT) is conservative, providing a margin of safety.

Although it has always been known that the dose-response at doses below the 25-rad average dose of the Atomic Bomb survivors could be supralinear, as opposed to sublinear, the possibility has not been 8 Note that the IAEA stands by its original wording, not accepting it as a typo. Personal Communication, 2006, D.

Kinley, IAEA public information, Vienna.

9 $50,000 net present value for a cancer death occurring 20 years from now, based on the 7% per year discount rate assumed in rhe Pilgrim Environmental Report, which leads to a factor of 4 reduction in present value for a cancer induced 20 years from now.

14

given much attention in the radiation protection community until now. 10 This is not the time forpro forma treatment of licensing applications. Whereas it would be unreasonable to require an applicant to redo analysis after every new paper is published in the scientific literature, the increase at low doses is very dramatic in this case. It represents a 5-fold increase over the risk estimated in BEIR VII (NRC 2005). Based on information in (Little 1998), it appears to represent a factor of 10 over the standard value used in the MACCS2 computer code, which is the code on which the applicants' analyses are based. With such a high reported increase, public health considerations have to take precedence over applicant convenience. The paper by Cardis et al., at the very minimum, demands that a thorough analysis be made of mitigation and alternatives to spent-fuel pool storage.

For example, application of the new risk coefficients would drive the risk of spent-fuel-pool accidents during decommissioning (without even considering terrorist threats) above the NRC's safety goal. See Figures ES-1, ES-2 of (Collins and Hubbard 2001).

Quantitative damage estimates for releases from Pilgrim and Vermont Yankee, assuming cancer risk coefficients are increased to accommodate the new epidemiologic studies:

This section presents a subset of consequence estimates for hypothetical releases of Cesium-137 from spent-fuel pools at Pilgrim and Vermont Yankee, assuming a 3-fold increase in cancer risk coefficients to conservatively account for the latest studies on radiation risk at low dose. To account for some weighting of other studies, I have chosen a value lower than the factor of 5-to-10 increase that is suggested by the study of (Cardis et al. 2005)."

As with earlier Tables, estimates are presented for economic costs and latent cancers. Variance in the estimates are not considered for the contention phase. See the Table footnotes and Appendix I for details. Political, psychological, and social impacts of hypothetical releases are not considered, although they could obviously be significant. As stated earlier, there appears to exist a "radiation syndrome" that affects a subset of exposed populations, causing debilitating psychiatric symptoms (Vyner 1983). Psychological effects of radiation disasters are expected to be most serious for children (CEH 2003).

10 There has been some discussion, however, that the A-Bomb survivor data produces low risk coefficients due to a healthy survivor effect (Stewart and Kneale 1993; Stewart and Kneale 1999). In addition, I have always wondered about the lowest dose data in Pierce, which seems to show a supralinear effect below 5 rem (Pierce et al. 1996), page 9.

11 Part of the factor of 5 comes from the use of a dose and dose rate effectiveness factor, which is commonly used with the MACCS2 code, as in (Beyea et al. 2004a).

15

Once again, releases lower than 10% of the Cesium-137 inventory, even releases too low to justify remediation, could have costs associated with loss in property value in the range of 10 to 100 billion dollars.

The damage estimates shown in the Tables are much less than the GDP of the US, which is about 12 trillion per year. However, some of the numbers are considerably larger than the annual payment on the national debt, which is about 350 billion dollars per year, indicating that government borrowing to cover the damage payments from a spent-fuel-pool fire could represent a major perturbation on the economy. Thus, once again, significant macroeconomic effects could be expected depending on the state of the economy at the time of any hypothetical release. The regional impacts would be expected to be the most serious. Estimating such effects are beyond the scope of this report.

The Tables include numbers in some cells to 3-significant figures. This does not imply any comparable level of accuracy.

16

Table 4. Cost estimatesfor a release ofl10% of spent-fuel-pool inventory of Cs-137assuming 3-fold increasein cancerrisk coefficient (billionsof dollars)

Category Pilgrim Vermont Yankee Comment Direct costsa) 89 79 Indirect administrative 89 79 costsb)

Loss in property values > 7-74 > 9-87 adjacent to treated areasc)

Costs associated with  ??  ?? Particularly important cleanup or demolition of for Pilgrim, with its downtown business and proximity to Boston commercial districts, heavy industrial areas, or high-rise apartment buildings.d)

Total > 186-253 > 167-245 a) As estimated from computations with MACCS2 at comparable sites with the parameters given in (Beyea et al. 2004a). An increase in the cancer risk numbers is mathematically equivalent to an increase in release magnitude, which is how the numbers in the Table were computed. Figures reduced by 1/3Td to account for wind rose effects.

b) Based on Chanin and Murfin. "We believe.., that it might be reasonable to double the cost estimates provided [here] in order to account for indirect costs." (Chanin and Murfin 1996), p. 6-3.

The factor might not be as great in the current case, however, because of economies of scale. We assume that litigation costs offset the economies of scale.

c) Assumed to be at least as great as the figures calculated in Table 1, where the cancer risk coefficient was left unchanged. Although not included in this total for the contention phase, loss in property value upon sale by government of remediated property should be included here. MACCS2 assumes no such loss.

d) We have not attempted an estimate for this category in the contention phase.

17

Table 5. Cost estimatesfor a releaseof -100% ofspent-fuel-pool inventory of Cs-137 assuming a three-foldincrease in cancer risk coefficient (billionsof dollars)

Category Pilgrim Vermont Yankee Comment Direct costsa). 283 353 Indirect administrative 283 353 costsb)

Loss in property values16-162 17-172 adjacent to treated areasc)

Costs associated with )? >) Particularly important cleanup or demolition of for Pilgrim, with its downtown business and proximity to Boston commercial districts, heavy industrial areas, or high-rise apartment buildingsd)

Costs due to delays in implementing remediation and deconstructiond)

Total > 582-728 > 723-878 a) As estimated from computations with MACCS2 at comparable sites with the parameters given in (Beyea et al. 2004a). An increase in the cancer risk numbers is mathematically equivalent to an increase in release magnitude, which is how the numbers in the Table were computed. Figures reduced by 1 /3rd to account for wind rose effects.

b) Based on Chanin and Murfin. "We believe.., that it might be reasonable to double the cost estimates provided [here] in order to account for indirect costs." (Chanin and Murfin 1996), p. 6-3.

The factor might not be as great in the current case, however, because of economies of scale. We assume that litigation costs offset the economies of scale.

c) Assumed to be at least as great as the figures calculated in Table 2, where the cancer risk coefficient was left unchanged. Although not included in this total for the contention phase, loss in property value upon sale by government of remediated property should be included here. MACCS2 assumes no such loss.

d) We have not attempted an estimate for this category in the contention phase.

18

Note that the latent cancer estimates in Table 6, below, are lower limits, because they only include the cancers from Cesium-137. This approximation ignores shorter isotopes in the fresh fuel in the pool, especially Cesium-134 (Benjamin 2003).

Table 6. Estimatesfor latent cancersfollowing releasesfrom the spent-fuelpools at either Pilgrim or Vermont Yankee (assuming a 3-fold increase in cancer risk number)

Category 10% release -100% release Latent cancers in main plume 4,000 12,000 path from residual contaminationa)

Latent cancers from deposited 4,000 12,000 resuspension b)

Total 8,000 24,000 a) Based on typical numbers for plants analyzed in (Beyea et al. 2004a) multiplied by a factor of 3.

Figures reduced by 1 /3 rd to account for wind rose effects. Cancers in the direct plume are reduced by more than a factor often from decontamination and deconstruction.

b) Assumes 10% resuspension and redistribution of deposited Cesium-137 resulting from a) wind removal in the first few weeks, and b) remediation/deconstruction efforts over successive years. It is possible that even the resuspended Cesium would produce concentrations high enough to justify remediation, with a corresponding reduction in projected cancers. However, clean-up costs would be increased.

Regulatory implications. The results in Tables 1-6, along with the discussion in the text suggest that:

The applicant should withdraw and revise its Environmental Reports for Pilgrim and Vermont Yankee.

The NRC should prepare supplements to the August 1979 Generic Environmental Impact Statement on handling and storage of spent fuel (NUREG-0575), and the May 1996 GEIS on license renewal (NUREG-1437). The revised documents should consider the new cancer risk coefficients published by Cardis et al. and Kristinina et al. For both reactor accidents and spent-fuel-pool fires, when relevant, the documents should consider loss of property value outside remediated areas. They should consider wind-driven resuspension, especially from remediation activities, that carries radioactivity to new areas in the immediate weeks and years following the release. Although MACCS2 does not directly account 19

for such refinements, it may be possible to mimic their effects in the program.12 In their economic calculations, the revised documents should include administrative and litigation costs associated with clean up and demolition. The ER for Pilgrim should consider the reduced turbulence over ocean water, including transport directly over water to the Boston area. The NUREG supplements should consider the impacts of coastal meteorology for reactors on the East and West Coasts. The program CALPUFF can be used to deal with dispersion over coastal waters.

12 This might be done by adding on extra plume segments to the end of a standard run, with varying delay times, and a total added release equal to the assumed resuspension fraction times the initial release. This will tend to produce the mathematical equivalent of resuspended material being carried indirections different from the main plume.

20

'4 1 1 Appendix I.

Variance in estimates are not considered in this report for the contention phase.

Based on the report of Gordon Thompson, the inventories at Pilgrim and Vermont Yankee are somewhat higher than the 35 MCi considered in (Beyea et al. 2004a). For Pilgrim, Dr. Thompson estimates 44 MCi; for Vermont Yankee, 39 MCi.

Thompson has also estimated a hotter heat rate for releases at Pilgrim and Vermont Yankee than was assumed in the calculations in (Beyea et al. 2004a). 106-128 MW vs 40 MW. Plume rise varies as the 1 13 d power of the heat rate in the standard "Briggs" formula for plume rise (Parks 1997), which implies a 50% greater rise than would have been calculated in the MACCS2 program that was used in the paper by Beyea, Lyman and von Hippel. For the contention phase of these proceedings, this difference has been ignored, since a 50% increase in plume rise is within 1-standard deviation of the value predicted by the formula (Irwin and Hanna 2004).

Rather than make new MACCS2 calculations for the contention phase of these proceedings, the azimuthally-averaged radial population distributions for both Pilgrim and Vermont Yankee have been compared as a function of distance with those for which economic and latent cancer consequences have been calculated in (Beyea et al. 2004a). It is the radial population numbers that drive the economic damage costs and cancer numbers. Figures 1 and 2 show the azimuthally-averaged radial population distributions for Pilgrim and Vermont Yankee for two different maximum distances. The CensusCD computer program (Geolytics 2002) was used to generate these population distributions. The same program was used in (Beyea et al. 2004a) for the five reactors, Catawba, Indian Point, LaSalle, Palo Verde, and TMI.

The effect of variation in wind direction at Pilgrim is to reduce the average damages and latent fatalities. Wind rose data taken from the Pilgrim FSAR shown in Figure 5 for the 300 foot tower suggest a reduction factor of 0.666 for that facility. See caption for Figure 5. I did not find similar data for a high tower in the FSAR for Vermont Yankee, so I have used the 0.666 factor determined for Pilgrim. Wind flows at the surface given in the Vermont Yankee FSAR are not particularly relevant to a hot release during a fire, since the plume will be elevated. The variance with angle appears to be quite large, because the population figures change with release angle, as shown in Figures 3 and 4.

For economic damages from the 10% releases, we are interested in populations out to 250 miles 21

(based on wedge model calculations). For the -100% releases, the corresponding distance is 700 miles.

The Pilgrim population figures best match Catawba out to 250 miles. For Vermont Yankee the population figures best match Lasalle out to 250 miles. Out to 700 miles, both Pilgrim and Vermont Yankee are most similar to Lasalle, although I discount the Lasalle cost figures to account for the lower population values of Pilgrim and Vermont Yankee.

Table 7, shows the relevant costs extracted from Table 3 of (Beyea et al. 2004a) and adjusted as indicated in the Table footnotes. These numbers were then fit to a power law function of release magnitude. The corresponding functions were used to generate costs estimates for the Pilgrim and Vermont Yankee releases estimated by Thompson, which differ somewhat from the releases assumed for a spent-fuel fire in (Beyea et al. 2004a).

Table Z Assigning damage cost estimates in billions ofdollars based on Table 3 of (Beyea et aL 2004a)

Release magnitude Pilgrim Vermont Yankee 3.5 MCi 71a) 54b) 35 MCi 219c) 243d) a) Cost figure for Catawba for a 3.5 MCi release.

b) Cost figure for Lasalle for a 3.5 MCi release.

c) Cost figure for Lasalle for a 35 MCi release reduced by 20%

d) Cost figure for Lasalle for a 35 MCi release reduced by 10%

Extrapolated and interpolated direct damage costs for Pilgrim and Vermont Yankee were computed from the following formulas:

Pilgrim: Damages = 0.66* 35* (release in Mci)°' 5 Vermont Yankee: Damages = 0.66

• 24 * (release in MCi)0 '65 The factor of 0.66 comes from wind-rose effects.

Administrative costs are taken equal to direct costs, following the suggestion of (Chanin and Murfin 1996). Property loss estimates are discussed below.

22

"The Power of Composting; The Power of Partnership," in Proceedings of the International Symposium on "The Science of Composting." 30 May - 2 June, 1995, Bologna, Italy.

"On the Importance of Thinking Like an Ecosystem," in Almanac for the Environment, Grosset/Putnam, NY, 1994.

"Beyond the Politics of Blame", EPRI Journal, July/August 1993 (reprinted in Agricultural Engineering).

Bringing Environmental Damage Costs into the Electricity Marketplace: Gains to be Expected and Pitfalls to be Avoided, presented at the National Conference on Environmental Externalities, Wyoming, Oct. 1990.

"Linking Energy Consumption with GNP", Review of Beyond Oil. Chemical & Engineering News, 64, p. 25-26, Dec. 1, 1986.

Articles and reports related to blomass and forest research:

Managing White-tailed Deer in Forest Habitat From an Ecosystem Perspective: Pennsylvania Case Study. (Latham, Beyea, Benner, Dunn, Fajvan, Freed, Grund, Horsley, Rhoads and Shissler)

Report by the Deer Management Forum for Audubon Pennsylvania and Pennsylvania Habitat Alliance, Harrisburg. xix + 340 pp., 2005 (Accessible at http://pa.audubon.ora/deer forum report main.htm)

"Use of meta-analysis to assign bird species to assemblages indicative of responsiveness to logging intensity in northeastern, hardwood forests." (Beyea, Hartley, Burger), 1 0 th Annual Conference of the Wildlife Society, Burlington, 2003.

"Bird Relationships to Habitat Characteristics Created by Timber Harvesting in Pennsylvania," B.

Ross, M. Morrison, W. Hoffman, T.S. Fredericksen, R.J. Sawicki, E. Ross, M.B. Lester, J. Beyea, B.N.

Johnson, Journal of the Pennsylvania Academy of Sciences, 74: 71-84, 2001 "The Impact of Logging on Wildlife: A Study in Northeastern Pennsylvania," TS Fredericksen, BD Ross, W Hoffman, E. Ross, M.L. Morrison, J. Beyea, MB Lester, BN Johnson, Journal of Forestry, 98(4):

4-10, 2000.

"Bioenergy in the United States: Progress and Possibilities," (with J Cook), Biomass and Bioenergv, 18. 2000.

"Relative Abundance and Species Richness of Herpetofauna in Forest Stands in Pennsylvania,"

(with BD Ross, T Fredericksen, E Ross, W Hoffman, ML. Morrison, MB Lester, BN Johnson, NJ Fredericksen), Forest Science, 46: 139-146, 2000.

"Using the Best Scientific Data for Endangered Species Conservation," (Smallwood, Beyea, Morrison), Environmental Management 24(4):421-435. 1999.

"Short-term understory plant community responses to timber harvesting on non-industrial private forestlands in Pennsylvania," (with TS Fredericksen, BD Ross, W Hoffman, ML. Morrison, BN Johnson, MB Lester, E Ross), Forest Ecology and Management, 116:129-139, 1999.

"Adequacy of Natural Hardwood Regeneration on Forestlands in Northeastern Pennsylvania,"

(with T.S. Fredericksen, B. Ross, W. Hoffman, M. Lester, M. Morrison, B.N. Johnson), Northern Journal of 9

Applied Forestry, 15(3):130-134,1998.

"Ecology of Agricultural Monocultures: Some Consequences for Biodiversity in Biomass Energy Farms," (with W. Hoffman and J. Cook), Proceedings of the 2nd Biomass Conference of the Americas, 1995, pp. 1618-1627.

"National Biofuels Roundtable : Principles and Guidelines for the Development of Biomass Energy Systems," Biomass and Bloenergy (Overend et al., to be published).

"Economic and Environmental Opportunities Through Biomass Development: Report of the CONEG Governors' Biomass Policy Roundtable," August 1995.

"Biomass Power: The Challenge and the Opportunity," Proceedings of the Annual Meeting of the Utility Biomass Energy Commercialization Association, 1994.

Avian Species Diversity and Policy Issues in Large-Scale Short-Rotation Wood Energy Crops:

Annual Reports to the Department of Energy (with Hoffman and Cook). 1992-1994 "Some Ecological Guidelines for Large-scale Biomass Plantations," Proceedings of the First Biomass Conference of the Americas, August 30-September 2, 1993. National Renewable Energy Laboratory. Pp. 33-41. (with Hoffman and Cook)

The Habitat Value of Short-Rotation Poplar Plantations: Avian Population Studies and Management Alternatives (with W. Hoffman, J. Cook), 1993.

Toward Ecological Guidelines for Large-Scale Biomass Energy Development, based on an Audubon/Princeton University Biomass Workshop, 1992.

"Biotechnological Advances in Biomass Energy and Chemical Production: Impacts on Wildlife and Habitat", (with K. Keeler), Critical Reviews in Biotechnology. CRC Press, Florida, February 1991.

"Potential Impacts of Biomass Production in the U.S. on Biological Diversity", (with Jim Cook and Kathleen Keeler), Annual Review of Energy, Calif., 1991. An adaptation appears in Biolopue, Sept. 1991.

"Preserving Biodiversity in the Face of Large Scale Demand for Biofuels", (with K.Keeler and J.Cook), Institute for Gas and Technology, Proceedings of Conference on Energy From Biomass Wastes XV (3/25-29/91), Wash.D.C., 1991.

"Biofuels: Answer to Global Warming or Growing Threat to Biodiversity?" In Forestry and Environment...Engineering Solutions - from a conference held June 5-6, 1991. American Society of Agricultural Engineers; St. Joseph, MI. (with Cook and Keeler)

Other Articles, Reports, and Testimony "Scientific misconceptions among Daubert gatekeepers: the need for reform of expert review procedures." (with Daniel Berger) Law and Contemporary Problems 64: 325-387, 2001.

"Scientists in the Courtroom," Science, 284:1125,1999 (letter).

"International Standard for Calculating Pollution Taxes," (with Michael Italiano), Proceedings of the 9 0 th Annual Meeting of the Air and Waste Management Association, Toronto, July 1997 10

"Avian Issues in Wind Development," in Proceedings of the 1995 Annual Meeting of the American Wind Energy Association, March 1995 "Principles for a National Avian-Wind Power Research Plan," Proceedings of National Avian-Wind Power Planning Meeting, Denver, CO, Department of Energy, February 1995.

"Environmental Concerns Regarding Electric Power Transmission in North American", (with John DeCicco and Stephen Bemow), Energy Policy, Jan. 1992.

Interview of Jan Beyea by Valerie Harms, Annals of Earth, Sept. 1991.

"The Impact of Environmental Issues on Public Support for Fusion Research", Physics and Society. 19(1), p. 6-7, January, 1990.

"Biotechnology's Promise - and Danger", (with J. P. Myers), Lt. Louis Post Dispatch, 1989.

"Physics Pro Bono", letter to Physics Today, (40,10), October 1987. Also, "Physics Pro Bono Redux," response, (41,8) August 1988.

"Protecting the Arctic National Wildlife Refuge," (with Brock Evans) before the Committee on Energy and Natural Resources, U.S. Senate, June 11, 1987.

"Oil and Gas Resources on Federal Lands: Wilderness and Wildlife Refuges", (Stege and Beyea), Annual Review of Energy, II, p. 143, 1986.

"Land Use Issues and the Media", published debate, Center for Communication, NYC, Oct.,

1984.

Implications for Mortality of Weakening the Clean Air Act, (with G. Steve Jordan), Audubon EPAD Report #18, May, 1982.

"In the Matter of Application of Orange and Rockland Counties, Inc. for Conversion to Coal of Lovett Units 4 and 5", testimony and cross-examination on the health impacts of eliminating scrubbers as a requirement for conversion to coal; Department of Environmental Resources, State of N.Y., Nov. 5, 1981.

Supervised Studies:

"The Decision Tree: A partnership for enhancing value on private forests," Matthew Keefer, Brad Ross, Proceedings of the Fragmentation2000 Conference, Anapolis, Maryland, September 17-20, 2000 "Compost and the Regeneration of our Nation's Degraded Lands" (a series of Audubon essays and brochures), 1995.

"Easthampton Residential Compost Pilot," National Audubon Society, 1995 The National Audubon Society's Almanac for the Environment: The Ecology of Everyday Life, Grosset/Putnam, NY, 1994 Alaskan Wildlife Species and Habitats That Are Sensitive to Offshore Oil and Gas Development, by Dorene A. Bolze, EPAD Report #30, January, 1987.

Side Effects of Renewable Energy Sources, by Larry Medsker, Revised Edition, Audubon EPAD Report #15, December, 1982.

11

Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants October 2000

Technical Contributors Group Leaders: Timothy E. Collins, DSSA George Hubbard, DSSA/SPLB Risk Assessment: Glenn Kelly, DSSANSPSB Michael Cheok, DSSA/SPSB Gareth Parry, DSSA Mark Rubin, DSSA/SPSB Robert Palla, DSSA/SPSB Primary Technical Support:

Seismic Goutam Bagchi, DE Robert Rothman, DE/EMEB Criticality Larry Kopp, DSSA/SRXB Anthony Ulses, DSSNSRXB Thermal-hydraulics Joseph Staudenmeier, DSSA/SRXB Walt Jenson, DSSA/SRXB Christopher Boyd, RES/DSARE/SMSAB Consequences Jason Schaperow, RES/DSARE/SMSAB Charles Tinkler, RES/DSARE Heavy Loads Edward Throm, DSSA/SPSB Secondary Technical Support:

Additional Support: Tanya Eaton, DSSAJSPLB David Diec, DSSA/SPLB Diane Jackson, DSSNSPLB John Lehning, DSSA/SPLB Study Preparation: Paula Magnanelli, DSSA

Technical Study of Spent Fuel Pool Accidents at Decommissioning Plants Table of Contents EXECUTIVE

SUMMARY

........................................................ viii

1.0 INTRODUCTION

........................................................ 1-1 2.0 THERMAL-HYDRAULIC ANALYSES ........................................ 2-1 3.0 RISK ASSESSMENT OF SPENT FUEL POOLS AT DECOMMISSIONING PLANTS... 3-1 3.1 Basis and Findings of SFP Risk Assessment ............................. 3-2 3.2 Characteristics of SFP Design and Operations for a Decommissioning Plant ... 3-3 3.3 Estimated Frequencies of Spent Fuel Uncovery and Assumptions That Influence the Results ........................................................ 3-6 3.3.1 Internal and External Initiator Frequency of Spent Fuel Pool Uncovery .... 3-7 3.3.2 Important Assumptions .................. ................ 3-11 3.4 Internal Event Scenarios Leading to Fuel Uncovery ....................... 3-12 3.4.1 Loss of Cooling ............................................. 3-12 3.4.2 Loss of Coolant Inventory ...................................... 3-14 3.4.3 Loss of Offsite Power from Plant-Centered and Grid Related Events ... 3-15 3.4.4 Loss of Offsite Power from Severe Weather Events ................ 3-15 3.4.5 Internal Fire ................................................. 3-16 3.4.6 Heavy Load Drops ........................................... 3-16 3.4.7 Spent Fuel Pool Uncovery Frequency at Times Other Than 1 year After Shutdown .................................................. 3-18 3.5 Beyond Design Basis Spent Fuel Pool Accident Scenarios (External Events) .. 3-18 3.5.1 Seismic Events ............................................. 3-18 3.5.2 Aircraft Crashes ............................................. 3-23 3.5.3 Tornadoes ................................................. 3-24 3.6 Criticality in Spent Fuel Pool ......................................... 3-25 3.7 Consequences and Risks of SFP Accidents ............................ 3-27 3.7.1 Consequences of SFP Accidents ............................... 3-28 3.7.2 Risk Modeling for SFP Accidents ................................ 3-34 3.7.3 Risk Results ................................................ 3-39 4.0 IMPLICATIONS OF SPENT FUEL POOL (SFP) RISK FOR REGULATORY REQUIREMENTS ....................................................... 4-1 4.1 Risk-Informed Decision Making ........................................ 4-1 4.1.1 Increases in Risk ............................................. 4-2 4.1.2 Defense-in-Depth ............................................. 4-6 4.1.3 Safety Margins ............................................... 4-8 4.1.4 , Implementation and Monitoring Program .......................... 4-10 4.2 Implications for Regulatory Requirements for Emergency Preparedness, Security, V October 2000

and Insurance ..................................................... 4-13 4.2.1 Emergency Preparedness ..................................... 4-13 4.2.2 Security ................................................... 4-14 4.2.3 Insurance .................................................. 4-15 5.0

SUMMARY

AND CONCLUSIONS ........................................... 5-1

6.0 REFERENCES

......................................................... 6-1 7.0 ACRONYM S ........................................................... 7-1 List of Figures ES-1 Individual Early Fatality Risk Within 1 Mile ..................................... xi ES-2 Individual Latent Cancer Fatality Risk Within 10 Miles ........................... xii Figure 2.1 Heatup Time From 30 °C to 900 °C .................................... 2-3 Figure 2.2 PWR Heatup Times for Air Cooling and Adiabatic Heatup .................. 2-3 Figure 3.1 Assumed Spent Fuel Pool Cooling System .............................. 3-3 Figure 3.2 Frequency of Spent Fuel Pool Seismically Induced Failure Based on LLNL Estimates and an HCLPF of 1.2 g Peak Spectral Acceleration ............. 3-21 Figure 3.3 Frequency of Spent Fuel Pool Seismically Induced Failure Based on EPRI Estimates and an HCLPF of 1.2 g Peak Spectral Acceleration .............. 3-22 Figure 3.7-1 Early Fatality Consequences for Spent Fuel Pool Source Terms ........ 3-32 Figure 3.7-2 Societal Dose Consequences for Spent Fuel Pool Source Terms ....... 3-33 Figure 3.7-3 Spent Fuel Pool Early Fatality Risk ................................ 3-41 Figure 3.7-4 Spent Fuel Pool Societal Risk .................................... 3-42 Figure 3.7-5 Sensitivity of Early Fatality Risk to Emergency Planning - Cask Drop Event ....................................................... 3-43 Figure 3.7-6 Sensitivity of Societal Risk to Emergency Planning - Cask Drop Event ... 3-44 Figure 3.7-7 Individual Early Fatality Risk Within 1 Mile .......................... 3-47 Figure 3.7-8 Individual Latent Cancer Fatality Risk Within 10 Miles ................. 3-48 List of Tables Table 2.1 Time to Heatup and Boiloff SFP Inventory Down to 3 Feet Above Top of Fuel (60 GW D/MTU) .................................................. 2-1 Table 3.1 Spent Fuel Pool Cooling Risk Analysis - Frequency of Fuel Uncovery ..... 3-9 Table 3.2 Spent Fuel Pool Cooling Risk Analysis - Frequency Partition for Air Flow ... 3-10 Table 3.7-1 Consequences of an SFP Accident With a High Ruthenium Source Term .. 3-29 Table 3.7-2 Consequences of an SFP Accident With a Low Ruthenium Source Term .. 3-30 Table 3.7-3 Frequency of Boil Down Events Leading to Spent Fuel Uncovery .......... 3-35 Table 3.7-4 Mean Frequency of Rapid Draindown Due to Seismic Events ............. 3-37 Table 3.7-5 Frequency of Rapid Draindown Spent Fuel Uncovery Due to Nonseismic Events .................. . .............................. 3-38 Table 4.1-1 Industry Decommissioning Commitments ............................ 4-11 Table 4.1-2 Staff Decommissioning Assumptions ............................... 4-12 Vi October 2000

.) Appendices Appendix 1A Thermal-hydraulics Analysis of Spent Fuel Pool Heatup .............. AlA-1 Appendix 1B Temperature Criteria for Spent Fuel Pool Analysis .................. A1B-1 Appendix 2 Assessment of Spent Fuel Pool Risk at Decommissioning Plants ....... A2-1 Appendix 2B Structural Integrity of Spent Fuel Pools Subject to Seismic Loads ...... A2B-1 Enhanced Seismic Checklist Comments Concerning Seismic Screening And Seismic Risk of Spent Fuel Pools for Decommissioning Plants by Robert P. Kennedy, October 1999 Response to Questions Concerning Spent Fuel Pool Seismic-Induced Failure Modes and Locations and the Expected Level of Collateral Damage Appendix 2C Structural Integrity of Spent Fuel Pool Structures Subject to Heavy Loads Drops ..................................................... A2C-1 Appendix 2D Structural Integrity of Spent Fuel Pool Structures Subject to Aircraft Crashes .................. ........................ A2D-1 Appendix 2E Structural Integrity of Spent Fuel Pool Structures Subject to Tornados ... A2E-1 Appendix 3 Assessment of the Potential for Criticality in Decommissioning Spent Fuel Pool ....................................................... A 3-1 Appendix 4 Consequence Assessment from Zirconium Fire ..................... A4-1 Appendix 4A Risk-informed Requirements for Decommissioning ................. A4A-1 Appendix 4B Effect of Fission Product Inventory Available for Release on Spent Fuel Pool Accident Consequences ................................... A4B-1 Appendix 4C Pool Performance Guideline ................................... A4C-1 Appendix 4D Change in Risk Associated with EP Relaxations ................... A4D-1 Appendix 5 November 12, 1999 Nuclear Energy Institute Commitment Letter ....... A5-1 Appendix 6 Public Comments ............................................. A6-1 Vii October 2000

EXECUTIVE

SUMMARY

This report documents a study of spent fuel pool (SFP) accident risk at decommissioning nuclear power plants. The study was undertaken to support development of a risk-informed technical basis for reviewing exemption requests and a regulatory framework for integrated rulemaking.

The staff published a draft study in February 2000 for public comment and significant comments were received from the public and the Advisory Committee on Reactor Safeguards (ACRS). To address these comments the staff did further analyses and also added sensitivity studies on evacuation timing to assess the risk significance of relaxed offsite emergency preparedness requirements during decommissioning. The staff based its sensitivity assessment on the guidance in Regulatory Guide (RG) 1.174, "An Approach for Using Probabilistic Risk Assessment In Risk-Informed Decisions On Plant-Specific Changes to the Licensing Basis."

The staff's analyses and conclusions apply to decommissioning facilities with SFPs that meet the design and operational characteristics assumed in the risk analysis. These characteristics are identified in the study as industry decommissioning commitments (IDCs) and staff decommissioning assumptions (SDAs). Provisions for confirmation of these characteristics would need to be an integral part of rulemaking.

The results of the study indicate that the risk at SFPs is low and well within the Commission's Quantitative Health Objectives (QHOs). The risk is low because of the very low likelihood of a zirconium fire even though the consequences from a zirconium fire could be serious. The results are shown in Figures ES-1 and ES-2. Because of the importance of seismic events in the analysis, and the considerable uncertainty in seismic hazard estimates, the results are presented for both the Lawrence Livermore National Laboratory (LLNL) and the Electric Power Research Institute (EPRI) seismic hazard estimates. In addition, to address a concern raised by the ACRS, the results also include a sensitivity to a large ruthenium and fuel fines release fraction. As illustrated in the figures, the risk is well below the QHOs for both the individual risk of early fatality and the individual risk of latent cancer fatality.

The study includes use of a pool performance guideline (PPG) as an indicator of low risk at decommissioning facilities. The recommended PPG value for events leading to uncovery of the spent fuel was based on similarities in the consequences from a SFP zirconium fire to the consequences from a large early release event at an operating reactor. A value equal to the large early release frequency (LERF) criterion ( x1 0-5 per year) was recommended for the PPG. By maintaining the frequency of events leading to uncovery of the spent fuel at decommissioning facilities below the PPG, the risk from zirconium fires will be low and consistent with the guidance in RG 1.174 for allowing changes to the plant licensing basis that slightly increase risk. With one exception (the H.B. Robinson site) all Central and Eastern sites which implement the IDCs and SDAs would be expected to meet the PPG regardless of whether LLNL or EPRI seismic hazard estimates are assumed. The Robinson site would satisfy the PPG if the EPRI hazard estimate is applied but not ifthe LLNL hazard is used. Therefore, Western sites and Robinson would need to be considered on a site-specific basis because of important differences in seismically induced failure potential of the SFPs.

Vifi October 2000

) The appropriateness of the PPG was questioned by the ACRS in view of potential effects of the fission product ruthenium, the release of fuel fines, and the effects of revised plume parameters.

The staff added sensitivity studies to its analyses to examine these issues. The consequences of a significant release of ruthenium and fuel fines were found to be notable, but not so important as to render inappropriate the staffs proposed PPG of lx1i05 per year. The plume parameter sensitivities were found to be of lesser significance.

In its thermal-hydraulic analysis, documented in Appendix 1A, the staff concluded that it was not feasible, without numerous constraints, to establish a generic decay heat level (and therefore a decay time) beyond which a zirconium fire is physically impossible. Heat removal is very sensitive to these additional constraints, which involve factors such as fuel assembly geometry and SFP rack configuration. However, fuel assembly geometry and rack configuration are plant specific, and both are subject to unpredictable changes after an earthquake or cask drop that drains the pool. Therefore, since a non-negligible decay heat source lasts many years and since configurations ensuring sufficient air flow for cooling cannot be assured, the possibility of reaching the zirconium ignition temperature cannot be precluded on a generic basis.

The staff found that the event sequences important to risk at decommissioning plants are limited to large earthquakes and cask drop events. For emergency planning (EP) assessments this is an important difference relative to operating plants where typically a large number of different sequences make significant contributions to risk. Relaxation of offsite EP a few months after shutdown resulted in only a "small change" in risk, consistent with the guidance of RG 1.174.

Figures ES-1 and ES-2 illustrate this finding. The change in risk due to relaxation of offsite EP is small because the overall risk is low, and because even under current EP requirements, EP was judged to have marginal impact on evacuation effectiveness in the severe earthquakes that dominate SFP risk. All other sequences including cask drops (for which emergency planning is expected to be more effective) are too low in likelihood to have a significant impact on risk. For comparison, at operating reactors additional risk-significant accidents for which EP is expected to provide dose savings are on the order of lx1i05 per year, while for decommissioning facilities, the largest contributor for which EP would provide dose savings is about two orders of magnitude lower (cask drop sequence at 2x10-7 per year).1 Other policy considerations beyond the scope of this technical study will need to be considered for EP requirement revisions and previous exemptions because a criteria of sufficient cooling to preclude a fire cannot be satisfied on a generic basis.

Insurance does not lend itself to a "small change in risk" analysis because insurance affects neither the probability nor the consequences of an event. As seen in figure ES-2, as long as a zirconium fire is possible, the long-term consequences of an SFP fire may be significant. These long-term consequences (and risk) decrease very slowly because cesium-137 has a half life of approximately 30 years. The thermal-hydraulic analysis indicates that when air flow has been restricted, such as might occur after a cask drop or major earthquake, the possibility of a fire lasts many years and a criterion of "sufficient cooling to preclude a fire" can not be defined on a 1Consistent with PRA limitations and practice, contributions to risk from safeguards events are not included in these frequency estimates. EP might also provide dose savings in such events.

ix October 2000

generic basis. Other policy considerations beyond the scope of this technical study will therefore need to be considered for insurance requirements.

The study also discusses implications for security provisions at decommissioning plants. For security, risk insights can be used to determine what targets are important to protect against sabotage. However, any revisions in security provisions should be constrained by an effectiveness assessment of the safeguards provisions against a design-basis threat. Because the possibility of a zirconium fire leading to a large fission product release cannot be ruled out even many years after final shutdown, the safeguards provisions at decommissioning plants should undergo further review. The results of this study may have implications on previous exemptions at decommissioning sites, devitalization of spent fuel pools at operating reactors and related regulatory activities.

The staff's risk analyses were complicated by a lack of data on severe-earthquake return frequencies, source term generation in an air environment, and SFP design variability. Although the staff believes that decommissioning rulemaking can proceed on the basis of the current assessment, more research may be useful to reduce uncertainties and to provide insights on operating reactor safety. In particular, the staff believes that research may be useful on source term generation in air, which could also be important to the risk of accidents at operating reactors during shutdowns, when the reactor coolant system and the primary containment may both be open.

In summary, the study finds that:

1. The risk at decommissioning plants is low and well within the Commission's safety goals.

The risk is low because of the very low likelihood of a zirconium fire even though the consequences from a zirconium fire could be serious.

2. The overall low risk in conjunction with important differences in dominant sequences relative to operating reactors, results in a small change in risk at decommissioning plants if offsite emergency planning is relaxed. The change is consistent with staff guidelines for small increases in risk.

3. Insurance, security, and emergency planning requirement revisions need to be considered in light of other policy considerations, because a criterion of "sufficient cooling to preclude a fire" cannot be satisfied on a generic basis.

4. Research on source term generation in an air environment would be useful for reducing uncertainties.

X October 2000

2.0 THERMAL-HYDRAULIC ANALYSES Analyses were performed to evaluate the thermal-hydraulic characteristics of spent fuel stored in the spent fuel pools (SFPs) of decommissioning plants and determine the time available for plant operators to take actions to prevent a zirconium fire. These are discussed in Appendix 1A.

The focus was the time available before fuel uncovery and the time available before the zirconium ignites after fuel uncovery. These times were utilized in performing the risk assessment discussed in Section 3.

To establish the times available before fuel uncovery, calculations were performed to determine the time to heat the SFP coolant to a point of boiling and then boil the coolant down to 3 feet above the top of the fuel. As can be seen in Table 2.1 below, the time available to take actions before any fuel uncovery is 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> or more for an SFP in which pressurized-water reactor (PWR) fuel has decayed at least 60 days.

Table 2.1 Time to Heatup and Boiloff SFP Inventory Down to 3 Feet Above Top of Fuel (60 GWD/MTU)

DECAY TIME PWR BWR 60 days 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> (>4 days) 145 hours0.00168 days <br />0.0403 hours <br />2.397487e-4 weeks <br />5.51725e-5 months <br /> (>6 days) 1 year 195 hours0.00226 days <br />0.0542 hours <br />3.224206e-4 weeks <br />7.41975e-5 months <br /> (>8 days) 253 hours0.00293 days <br />0.0703 hours <br />4.183201e-4 weeks <br />9.62665e-5 months <br /> (>10 days) 2 years 272 hours0.00315 days <br />0.0756 hours <br />4.497354e-4 weeks <br />1.03496e-4 months <br /> (>11 days) 337 hours0.0039 days <br />0.0936 hours <br />5.57209e-4 weeks <br />1.282285e-4 months <br /> (>14 days) 5 years 400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> (>16 days) 459 hours0.00531 days <br />0.128 hours <br />7.589286e-4 weeks <br />1.746495e-4 months <br /> (>19 days) 10 years 476 hours0.00551 days <br />0.132 hours <br />7.87037e-4 weeks <br />1.81118e-4 months <br /> (>19 days) 532 hours0.00616 days <br />0.148 hours <br />8.796296e-4 weeks <br />2.02426e-4 months <br /> (>22 days)

The analyses in Appendix 1A determined that the amount of time available (after complete fuel uncovery) before a zirconium fire depends on various factors, including decay heat rate, fuel burnup, fuel storage configuration, building ventilation rates and air flow paths, and fuel cladding oxidation rates. While the February 2000 study indicated that for the cases analyzed a required decay time of 5 years would preclude a zirconium fire, the revised analyses show that it is not feasible, without numerous constraints, to define a generic decay heat level (and therefore decay time) beyond which a zirconium fire is not physically possible. Heat removal is very sensitive to these constraints, and two of these constraints, fuel assembly geometry and spent fuel pool rack configuration, are plant specific. Both are also subject to unpredictable changes as a result of the severe seismic, cask drop, and possibly other dynamic events which could rapidly drain the pool. Therefore, since the decay heat source remains nonnegligible for many years and since configurations that ensure sufficient air flow 2 for cooling cannot be assured, a zirconium 2Although a reduced air flow condition could reduce the oxygen levels to a point where a fire would not be possible, there is sufficient uncertainty in the available data as to when this level would be reached and if it could be maintained. It is not possible to predict when a zirconium fire would not occur because of a lack of oxygen. Blockage of the air flow around the fuel could be 2-1 October 2000

) fire cannot be precluded, although the likelihood may be reduced by accident management measures.

Figure 2.1 plots the heatup time air-cooled PWR and BWR fuel take to heat up from 30 0C to 900 0C versus time since reactor shutdown. The figure shows that after 4 years, PWR fuel could reach the point of fission product release in about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Figure 2.2 shows the timing of the event by comparing the air-cooled calculations to an adiabatic heatup calculation for PWR fuel with a bumup of 60 GWD/MTU. The figure indicates an unrealistic result that until 2 years have passed the air-cooled heatup rates are faster than the adiabatic heatup rates. This is because the air-cooled case includes heat addition from oxidation while the adiabatic case does not. In the early years after shutdown, the additional heat source from oxidation at higher temperatures is high enough to offset any benefit from air cooling. This result is discussed further in Appendix 1A. The results using obstructed airflow (adiabatic heatup) show that at 5 years after shutdown, the release of fission products may occur approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the accident.

In summary, 60 days after reactor shutdown for boildown type events, there is considerable time

(>100 hours) to take action to preclude a fission product release or zirconium fire before uncovering the top of the fuel. However, if the fuel is uncovered, heatup to the zirconium ignition temperature during the first years after shutdown would take less than 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> even with unobstructed air flow. After 5 years, the heatup would take at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> even with obstructed air flow cases. Therefore, a zirconium fire would still be possible after 5 years for cases involving obstructed air flow and unsuccessful accident management measures. These results and how they affect SFP risk and decommissioning regulations are discussed in Sections 3 and 4 of this study.

caused by collapsed structures and/or a partial draindown of the SFP coolant or by reconfiguration of the fuel assemblies during a seismic event or heavy load drop. A loss of SFP building ventilation could also preclude or inhibit effective cooling. As discussed in Appendix 1A, air flow blockage without any recovery actions could result in a near-adiabatic fuel heatup and a zirconium fire even after 5 years.

2-2 October 2000

.4

-,)

Heatup Time to Release (Air Cooling) 40 2.30 0

PWR a)

E 20 BWR CU 1~0 0 - I 0.164 1 2 3 shutdown time (years)

Figure 2.1 Heatup Time From 30 0C to 900 °C PWR Adiabatic vs. Air cooled 30

,~25 C,,

.020 Air Cooled E 15 Adiabatic

.10 cc 0

0.164 1 2 3 4 5 shutdown time (years)

Figure 2.2 PWR Heatup Times for Air Cooling and Adiabatic Heatup 2-3 October 2000

-A-

~1

SAFETY AND SECURITY OF COMMERCIAL SPENT NUCLEAR FUEL STORAGE Public Report Committee on the Safety and ?ecurity of Commercial Spent Nuclear Fuel Storage Board on Radioactive Waste Management Division on Earth and Life Studies NATIONAL RESEARCH COUNCIL OF THE NA7TONAL ACADEMIES THE NATIONAL ACADEMIES PRESS Washington, D.C.

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THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

This study was supported by grant number NRC-04-04-067 between the National Academy of Sciences and the U.S. Nuclear Regulatory Commission. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.

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The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine.

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general polici6s determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and" engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Wm. A. Wulf are chair and vice chair, respectively, of the National Research Council www.national-academies.org

COMMITTEE ON THE SAFETY AND SECURITY OF COMMERCIAL SPENT NUCLEAR FUEL STORAGE LOUIS J. LANZEROTTI, Chair,New Jersey Institute of Technology, Newark, and Lucent Technologies, Murray Hill CARL A. ALEXANDER, Battelle Memorial Institute, Columbus, Ohio ROBERT M. BERNERO, U.S. Nuclear Regulatory Commission (retired), Gaithersburg, Maryland M. QUINN BREWSTER, University of Illinois, Urbana-Champaign GREGORY R. CHOPPIN, Florida State University, Tallahassee NANCY J. COOKE, Arizona State University, Mesa LOUIS ANTHONY COX, Jr.,1 Cox Associates, Inc., Denver, Colorado GORDON R. JOHNSON, Network Computing Services, Minneapolis, Minnesota ROBERT P. KENNEDY, RPK Structural Mechanics Consulting, Escondido, California KENNETH K. KUO, Pennsylvania State University, University Park RICHARD T. LAHEY, Jr., Rensselaer Polytechnic Institute, Troy, New York KATHLEEN R. MEYER, Keystone Scientific, Inc., Fort Collins, Colorado FREDERICK J. MOODY, GE Nuclear Energy (retired), Murphys, California TIMOTHY R. NEAL, Los Alamos National Laboratory, Los Alamos, New Mexico JOHN WREATHALL, 1 John Wreathall &Company, Inc., Dublin, Ohio LORING A. WYLLIE, Jr., Degenkolb Engineers, San Francisco, California PETER D. ZIMMERMAN, King's College London, United Kingdom Staff KEVIN D. CROWLEY, Study Director BARBARA PASTINA, Senior Program Officer MICAH D. LOWENTHAL, Senior Program Officer ELISABETH A. REESE, Program Officer DARLA THOMPSON, Research Associate TONI G. GREENLEAF, Administrative Associate Drs. Cox and Wreathall resigned from the committee on February 26 and March 17, 2004, respectively.

iv

BOARD ON RADIOACTIVE WASTE MANAGEMENT RICHARD A. MESERVE, 1 Chair,Camegie Institution, Washington, D.C.

ROBERT M. BERNERO, U.S. Nuclear Regulatory Commission (retired), Gaithersburg, Maryland SUE B. CLARK, Washington State University, Pullman ALLEN G. CROFF, Oak Ridge National Laboratory (retired), Tennessee DAVID E. DANIEL, University of Illinois, Urbana RODNEY C. EWING, University of Michigan, Ann Arbor ROGER L. HAGENGRUBER, University of New Mexico, Albuquerque KLAUS KOHN, Technische Universitat Clausthal, Germany HOWARD C. KUNREUTHER, University of Pennsylvania, Philadelphia SUSAN M.LANGHORST, Washington University, St. Louis, Missouri NIKOLAI R LAVEROV, Russian Academy of Sciences, Moscow MILTON LEVENSON, Bechtel International (retired), Menlo Park, California PAUL A. LOCKE, Johns Hopkins University, Baltimore, Maryland NORINE E. NOONAN, College of Charleston, South Carolina EUGENE A. ROSA, Washington State University, Pullman ATSUYUKI SUZUKI, Nuclear Safety Commission of Japan, Tokyo Staff KEVIN D. CROWLEY, Director MICAH D. LOWENTHAL, Senior Program Officer BARBARA PASTINA, Senior Program Officer JOHN R. WILEY, Senior Program Officer TONI GREENLEAF, Administrative Associate DARLA J. THOMPSON, Research Associate LAURA D. LLANOS, Senior Program Assistant MARILI ULLOA, Senior Program Assistant JAMES YATES, JR., Office Assistant Dr. Meserve did not participate in the oversight of this study.

V

ACKNOWLEDGMENTS This study would not have been possible without the help of several organizations and individuals who were called upon for information and advice. The committee would like to acknowledge especially the following organizations and individuals for their help:

• Congressional staff members Kevin Cook, Terry Tyborowski, and Jeanne Wilson (retired) for their guidance on the study task.

• Nuclear Regulatory Commission staff Farouk Eltawila, who served as the primary liaison for this study, and Charles Tinkler and Francis (Skip) Young for their support of the committee's information-gathering activities.

" Department of Homeland Security staff member Jon MacLaren, who also served as a liaison to the committee.

• Steve Kraft and John Vincent (deceased) of the Nuclear Energy Institute and staff of Energy Resources International for providing information about spent fuel storage practices in industry.

• ENTERGY Corp., Exelon Corp, and Arizona Public Service Corp. staff for organizing tours of the Braidwood, Dresden, Indian Point, and Palo Verde nuclear generating stations.

• German organizations and individuals who helped organize a tour of spent fuel storage facilities in Germany. These organizations and individuals are explicitly

.acknowledged in Appendix C.

• Speakers (see Appendix A) and participants at committee meetings as well as those who sent written comments for providing their knowledge and perspectives on this important matter.

This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council's Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:

John F. Aheame, Sigma Xi and Duke University Romesh C. Batra, Virginia Polytechnic Institute and State University Robert J. Budnitz, Lawrence Livermore National Laboratory Philip R. Clark, GPU Nuclear Corporation (retired)

Richard L. Garwin, IBM Thomas J. Watson Research Center Roger L. Hagengruber, The University of New Mexico Darleane C. Hoffman, E.O. Lawrence Berkeley National Laboratory Melvin F. Kanninen, MFK Consulting Services Milton Levenson, Bechtel International (retired)

Allison Macfarlane, Massachusetts Institute of Technology Richard A. Meserve, Carnegie Institution of Washington vii

Donald R. Olander, University of California, Berkeley Theofanis G. Theofanous, University of California, Santa Barbara George W. Ulfrich, SAIC Frank N. von Hippel, Princeton University Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the report's conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Chris G. Whipple, ENVIRON International Corporation, and R. Stephen Berry, University of Chicago. Appointed by the National Research Council, they were responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.

viii

CONTENTS Note to Readers, 1 Summary for Congress, 3 Executive Summary, 5

1. Introduction and Background, 12 1.1 Context for this study, 12 1.2 Strategy to address the study charges, 13 1.3 Report roadmap, 16 1.4 Background on spent nuclear fuel and its storage, 16

2. Terrorist Attacks on Spent Fuel Storage, 25 2.1 Eackground on risk, 25.

2.2 T~rrorist attack scenarios, 28 2.3 Risks of terrorist attacks on spent fuel storage facilities, 34 2.4 Findings and recommendations, 36

3. Spent Fuel Pool Storage, 38 3.1 Background on spent fuel pool storage, 40 3.2 Previous studies on safety and security of pool storage, 44 3.3 Evaluation of the potential risks of pool storage, 47 3.4 Findings and recommendations, 57

4. Dry Cask Storage and Comparative Risks, 60 4.1 Backgrouuid on dry cask storage, 61 4.2 Evaluation of potential risks of dry cask storage, 64 4.3 Potential advantbges of dry storage over wet storage, 68 4.4 Findings and recommendations, 69

5. Implementation Issues, 75 5.1 Timing issues, 75 5.2 Communication issues, 75 5.3 Finding and recommendation, 77 References, 79 Appendixes A. Information-gathering sessions, 83 B. Biographical sketches of committee members, 87 C. Tour of selected spent fuel storage-related installations in Germany, 92 D. Historical development of current commercial power reactor fuel operations, 100 E. Glossary, 108 F. Acronyms, 115 ix i'

NOTE TO READERS This report is based on a classified report that was developed at the request of the U.S. Congress with sponsorship from the Nuclear Regulatory Commission and the Department of Homeland Security. This report contains all of the findings and recommendations that appear in the classified report. Some have been slightly reworded and other sensitive information that might allow terrorists to exploit potential vulnerabilities has been redacted to protect national security. Nevertheless, the National Research Council and the authoring committee believe that this report provides an accurate summary of the classified report, including its findings and recommendations.

The authoring committee for this report examined the potential consequences of a large number of scenarios for attacking spent fuel storage facilities at commercial nuclear power plants. Some of these scenarios were developed by the Nuclear Regulatory Commission as part of its ongoing vulnerability analyses, whereas others were developed by the committee based upon the expertise of its members or suggestions from participants at the committee's open meetings. The committee focused its discussions about terrorist attacks on the concept of maximum credible scenarios.These are defined by the committee to be physically realistic classes of attacks that, if carried out successfully, would produce the most serious potential consequences within that class. In a practical sense they can be said to bound the consequences for a given type of attack. Such scenarios could in some cases be very difficult to carry out because they require a high level of skill and knowledge or luck on the part of the attackers. It was nevertheless useful to analyze these scenarios because they provide decision makers with a better understanding of the full range of potential consequences from terrorist attacks.

The committee uses the term potentialconsequences advisedly. It is important to recognize that-a terrorist attack on a spent fuel storage facility would not necessarily result in the release of any radioactivity to the environment. The consequences of such an attack would depend not only on the nature of the attack itself, but also on the construction of the spent fuel storage facility; its location relative to surrounding features that might shield it from the attack; and the ability of the guards and operators at the facility to respond to the attack and/or mitigate its consequences. Facility-specific analyses are required to determfhe the potential vulnerability of a given facility to a given type of terrorist attack.

Congress asked the National Research Council for technical advice related to the vulnerability of spent fuel storage facilities to terrorist attacks, Congress, the Nuclear Regulatory Commission, and the Department of Homeland Security are responsible for translating this advice into policy actions. This will require the balancing of costs, risks, and benefits across the nation's industrial infrastructure. The committee was not asked to examine the potential vulnerabilities of other types of infrastructure to terrorist attacks or the consequences of such attacks. While such comparisons will likely be difficult, they will be essential for ensuring that the nation's limited resources are used judiciously in protecting its citizens from terrorist attacks.

I

SUMMARY

FOR CONGRESS The U.S. Congress asked the National Academies to provide independent scientific and technical advice on the safety and security of commercial spent nuclear fuel storage in the United States, specifically with respect to the following charges:

• Potential safety and security risks of spent nuclear fuel presently stored in cooling pools at commercial nuclear reactor sites.

0 Safety and security advantages, if any, of dry cask storage versus wet pool storage at these reactor sites.

• Potential safety and security advantages, if any, of dry cask storage using various single-, dual-, and multi-purpose cask designs.

• The risks of terrorist attacks on these materials and the risk these materials might be used to construct a radiological dispersal device.

Congress requested that the National Academies produce a classified report that addresses these charges within 6 months and also provide an unclassified summary for unlimited public distribution. The first request was fulfilled in July 2004. This report fulfills the second request.

The highlights of the report are as follows:

(1) Spent fuel pools are necessary at all operating nuclear power plants to store recently discharged fuel.

(2) The committee judges that successful terrorist attacks on spent fuel pools, though difficult, are possible.

(3) Ifan attack leads to a propagating zirconium cladding fire, it could result in the release of large amounts of radioactive material.

(4) Additional analyses are needed to understand more fully the vulnerabilities and consequences of events that could lead to propagating zirconium cladding fires.

(5) It appears to be feasible to reduce the likelihood of a zirconium cladding fire by rearranging spent fuel assemblies in the pool and making provision for water-spray systems that would be able to cool the fuel, even if the pool or overlying-building were severely damaged.

(6) Dry cask storage has inherent security advantages over spent fuel pool storage, but it can only be used to store older spent fuel.

(7) There are no large security differences among different storage-cask designs.

(8) It would be difficult for terrorists to steal enough spent fuel from storage facilities for use in significant radiological dispersal devices (dirty bombs).

The statement of task does not direct the committee to recommend whether the transfer of spent fuel from pool to dry cask storage should be accelerated. The committee judges, however, that further engineering analyses and cost-benefit studies would be needed before decisions on this and other mitigative measures are taken. The report contains detailed recommendations for improving the security of spent fuel storage' regardless of how it is stored.

3

EXECUTIVE

SUMMARY

In the Fiscal Year 2004 Energy and Water Development Conference Report, the U.S. Congress asked the National Academies to provide independent scientific and technical advice on the safety and security1 of commercial spent nuclear fuel storage in the United States, specifically with respect to the following four charges:

(1) Potential safety and security risks of spent nuclear fuel presently stored in cooling pools at commercial reactor sites.

(2) Safety and security advantages, if any, of dry cask storage versus wet pool storage at these reactor sites.

(3) Potential safety and security advantages, if any, of dry cask storage using various single-, dual-, and multi-purpose cask designs.

(4) The risks of terrorist attacks on these materials and the risk these materials might be used to construct a radiological dispersal device.

Congress requested that the National Academies produce a classified report that addresses these charges within 6 months and also provide an unclassified summary for unlimited public distribution. The first request was fulfilled in July 2004. This report fulfills the second request.

Spent nuclear fuel is stored at commercial nuclear power plant sites in two configurations:

• In water-filled pools, referred to as spent fuel pools.

0 In dry casks that are designed either for storage (single-purpose casks) or both storage and transportation (dual-purpose casks). There are two basic cask designs: bare-fuel casks and canister-based casks, which can be licensed for either single- or dual-purpose use, depending on their design.

Spent fuel pools are currently in use at all 65 sites with operating commercial nuclear power reactors, at 8 sites where commercial power reactors have been shut down, and at one site not associated with an operating or shutdown power reactor. Dry-cask storage facilities have been established at 28 operating, shutdown, or decommissioned power plants. The nuclear industry projects that up to three or four nuclear power plants will reach full capacity in their spent fuel pools each year for at least the next 17 years.

The congressional request for this study was prompted by conflicting public claims about the safety and security of commercial spent nuclear fuel storage at nuclear power plants. Some analysts have argued that the dense packing of spent fuel in cooling pools at nuclear power plants does not allow a sufficient safety margin in the event of a loss-of-pool-coolant event from an accident or terrorist attack. They assert that such events could result in the release of large quantities of radioactive material to the environment if the zirconium cladding of the spent fuel overheats and ignites. To reduce the potential for such fires, these Inthe context of this study, safety refers to measures that protect spent nuclear fuel storage facilities against failure, damage, human error, or other'accidents that would disperse radioactivity in the environment. Security refers to measures to protect spent fuel storage facilities against sabotage, attacks, or theft.

5

6 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE analysts have suggested that spent fuel more than five years old be removed from the pool and stored in dry casks, and that the remaining younger fuel be reconfigured in the pool to allow more space for air cooling in the event of a loss-of-pool-coolant event.

The committee that was appointed to perform the present study examined the vulnerability of spent fuel stored in pools and dry casks to accidents and terrorist attacks.

Any event that results in the breach of a spent fuel pool or a dry cask, whether accidental or intentional, has the potential to release radioactive material to the environment. The committee therefore focused its limited time on understanding two issues: (1) Under what circumstances could pools or casks be breached? And (2) what would be the radioactive releases from such breaches?

To address these questions, the committee performed a critical review of the security analyses that have been carried out by the Nuclear Regulatory Commission and its contractors, the Department of Homeland Security, industry, and other independent experts to determine if they are objective, complete, and credible. The committee was unable to examine several important issues related to these questions either because it was unable to obtain needed information from the Nuclear Regulatory Commission or because of time constraints. Details are provided in Chapters 1 and 2.

The committee's findings and recommendations from this analysis are provided below, organized by the four charges of the study task. The ordering of the charges has been rearranged to provide a more logical exposition of results.

CHARGE 4: RISKS OF TERRORIST ATTACKS ON THESE MATERIALS AND THE RISK THESE MATERIALS MIGHT BE USED TO CONSTRUCT A RADIOLOGICAL DISPERSAL DEVICE The concept of risk as applied to terrorist attacks underpins the entire statement of task for this study. Therefore, the committee examined this final charge first to provide the basis for addressing the remainder of the task statement. The committee's examination of Charge 4 is provided in Chapter 2. On the basis of this examination, the committee offers the following findings and recommendations numbered according to the chapters in which they appear:

FINDING 2A: The probability of terrorist attacks on spent fuel storage cannot be assessed quantitatively or comparatively. Spent fuel storage facilities cannot be dismissed as targets for such attacks because it is not possible to predict the behavior and motivations of terrorists, and because of the attractiveness of spent fuel as a terrorist target given the well known public dread of radiation. Terrorists view nuclear power plant facilities as desirable targets because of the large inventories of radioactivity they contain. While it would be difficult to attack such facilities, the committee judges that attacks by knowledgeable terrorists with access to appropriate technical means are possible. It is important to recognize, however, that an attack that damages a power plant or its spent fuel storage facilities would not necessarily result in the release of any radioactivity to the environment. There are potential steps that can be taken to lower the potential consequences of such attacks.

EXECUTIVE

SUMMARY

7 FINDING 2B: The committee judges that the likelihood terrorists could steal enough spent fuel for use in a significant radiological dispersal device is small.

Removal of a spent fuel assembly from the pool or dry cask would prove extremely difficult under almost any terroristattack scenario. Attempts by a knowledgeable insider(s) to remove single rods and related debris from the pool might prove easier, but the amount of material that could be removed would be small. Moreover, superior materials could be stolen or purchased more easily from other sources. Even though the likelihood of spent fuel theft appears to be small, it is nevertheless important that the protection of these materials be maintained and improved as vulnerabilities are identified.

RECOMMENDATION: The Nuclear Regulatory Commission should review and upgrade, where necessary, its security requirements for protecting spent fuel rods not contained in fuel assemblies from theft by knowledgeable insiders, especially in facilities where individual fuel rods or portions of rods are being stored in pools.

FINDING 2C: A number of security improvements at nuclear power plants have been instituted since the events of September 11, 2001. However, the Nuclear Regulatory Commission did not provide the committee with enough information to evaluate' the effectiveness of these procedures for protecting stored spent fuel. Surveillance and other human-factors related security procedures are just as important as the physical barriers in preventing and mitigating terrorist attacks. Although the committee did leam about some of the changes that have been instituted since the September 11, 2001, attacks, it was not provided with enough information to evaluate the effectiveness of procedures now in place.

RECOMMENDATION: Although the committee did not specifically investigate the effectiveness and adequacy of improved surveillance and security measures for protecting stored spent fuel, an assessment of current measures should be performed by an independent2 organization.

CHARGE 1: POTENTIAL SAFETY AND SECURITY RISKS OF SPENT NUCLEAR FUEL STORED IN POOLS The committee's examination of Charge I is provided in Chapter 3. On the basis of this examination, the committee offers the following findings and recommendations:

FINDING 3A: Pool storage is required at all operating commercial nuclear power plants to cool newly discharged spent fuel. Freshly discharged spent fuel generates too much decay heat to be passively air cooled. This fuel must be stored in a pool that has an active heat removal system (i.e., water pumps and heat exchangers) for at least one year before being moved to dry storage. Most dry storage systems are licensed to store fuel that has been out of the reactor for at least five years. Although spent fuel younger than five years could be stored in dry casks, the changes required for shielding and heat-removal 2 That is, independent of the Nuclear Regulatory Commission and the nuclear industry.

8 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE could be substantial, especially for fuel that has been discharged for less than about three years.

FINDING 3B: The committee finds that, under some conditions, a terrorist attack that partially or completely drained a spent fuel pool could lead to a propagating zirconium cladding fire and the release of large quantities of radioactive materials to the environment. Details are provided in the committee's classified report.

FINDING 3C: It appears to be feasible to reduce the likelihood of a zirconium cladding fire following a loss-of-pool-coolant event using readily implemented measures. The following measures appear to have particular merit: Reconfiguring the spent fuel in the pools (i.e., redistribution of high decay-heat assemblies so that they are surrounded by low decay-heat assemblies) to more evenly distribute decay-heat loads and enhance radiative heat transfer; limiting the frequency of offloads of full reactor cores into spent fuel pools, requiring longer shutdowns of the reactor before any fuel is offloaded, and providing enhanced security when such offloads must be made; and development of a redundant and diverse response system to mitigate loss-of-pool-coolant events that would be capable of operation even if the pool or overlying building were severely damaged.

FINDING 3D: The potential vulnerabilities of spent fuel pools to terrorist attacks are plant-design specific. Therefore, specific vulnerabilities can be understood only by examining the characteristics of spent fuel storage at each plant. As described in Chapter 3, there are substantial differences in the designs of spent fuel pools that make them more or less vulnerable to certain types of terrorist attacks.

FINDING 3E: The Nuclear Regulatory Commission and independent analysts have made progress in understanding some vulnerabilities of spent fuel pools to certain terrorist attacks and the consequences of such attacks for releases of radioactivity to the environment. However, additional work on specific issues is needed urgently. The analyses carried out to date provide a general understanding of spent fuel behavior in a loss-of-pool-coolant event and the vulnerability of spent fuel pools to certain terrorist attacks that could cause such events to occur. The work to date, however, has not been sufficient to adequately understand the vulnerabilities and consequences of such events. Additional analyses are needed to fill in the knowledge gaps so that well-informed policy decisions can be made.

RECOMMENDATION: The Nuclear Regulatory Commission should undertake additional best-estimate analyses to more fully understand the vulnerabilities and consequences of loss-of-pool-coolant events that could lead to a zirconium cladding fire. Based on these analyses, the Commission should take appropriate actions to address any significant vulnerabilities that are identified. The committee provides details on additional analyses that should be carried out in its classified report. Cost-benefit considerations will be an important part of such decisions.

RECOMMENDATION: While the work described in the previous recommendation under Finding 3E, above, is being carried out, the Nuclear Regulatory Commission should ensure that power plant operators take prompt and effective measures to reduce the consequences of loss-of-pool.coolant

EXECUTIVE

SUMMARY

9 events in spent fuel pools that could result in propagating zirconium cladding fires. The committee judges that there are at least two such measures that should be implemented promptly:

• Reconfiguring of fuel in the pools so that high decay-heat fuel assemblies are surrounded by low decay-heat assemblies. This will more evenly distribute decay-heat loads, thus enhancing radiative heat transfer in the event of a loss of pool coolant.

• Provision for water-spray systems that would be able to cool the fuel even if the pool or overlying building were severely damaged.

Reconfiguring of fuel in the pool would be a prudent measure that could probably be implemented at all plants at little cost, time, or exposure of workers to radiation. The second measure would probably be more expensive to implement and may not be needed at all plants, particularly plants in which spent fuel pools are located below grade or are protected from external line-of-sight attacks by exterior walls and other structures.

The committee anticipates that the costs and benefits of options for implementing the second measure would be examined to help decide what requirements would be imposed. Further, the committee does not presume to anticipate the best design of such a system-whether it should be installed on the walls of a pool or deployed from a location where it is unlikely to be corn'promised by the same attack-but simply notes the demanding requirements such a system must meet.

CHARGE 3: POTENTIAL SAFETY AND SECURITY ADVANTAGES, IF ANY, OF DIFFERENT DRY CASK STORAGE DESIGNS The third charge to the committee focuses exclusively on the safety and security of dry casks. The committee addressed this charge first in Chapter 4 to provide the basis for the comparative analysis between dry casks and pools as called for in Charge 2.

FINDING 4A: Although there are differences in the robustness of different dry cask designs (e.g., bare-fuel versus canister-based), the differences are not large when measured by-the absolute magnitudes of radionuclide releases in the event of a breach. All storage cask designs are vulnerable to some types of terrorist attacks, but the quantity of radioactive material releases predicted from such attacks is relatively small.

These releases are not easily dispersed in the environment.

FINDING 4B: Additional steps can be taken to make dry casks less vulnerable to potential terrorist attacks. Although the vulnerabilities of current cask designs are already small, additional, relatively simple steps can be taken to reduce them as discussed in Chapter 4.

RECOMMENDATION: The Nuclear Regulatory Commission should consider using the results of the vulnerability analyses for possible upgrades of requirements in 10 CFR 72 for dry casks, specifically to improve their resistance to terrorist attacks. The committee was told by

10 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 10 Nuclear Regulatory Commission staff that such a step is already under consideration.

CHARGE 2: SAFETY AND SECURITY ADVANTAGES, IF ANY, OF DRY CASK STORAGE VERSUS WET POOL STORAGE In Chapter 4, the committee offers the following findings and recommendations with respect to the comparative component of Charge 2:

FINDING 4C: Dry cask storage does not eliminate the need for pool storage at operating commercial reactors. Under present U.S. practices, dry cask storage can only be used to store fuel that has been out of the reactor long enough (generally greater than five years under current practices) to be passively air cooled.

FINDING 4D: Dry cask storage for older, cooler spent fuel has two inherent advantages over pool storage: (1)It is a passive system that relies on natural air circulation for cooling; and (2) it divides the inventory of that spent fuel among a large number of discrete, robust containers. These factors make it more difficult to attack a large amount of spent fuel at one time and also reduce the consequences of such attacks. The robust construction of these casks prevents large-scale releases of radioactivity in all of the attack scenarios examined by the committee in its classified report.

FINDING 4E: Depending on the outcome of plant-specific vulnerability analyses described in the committee's classified report, the Nuclear Regulatory Commission might determine that earlier movements of spent fuel from pools into dry cask storage would be prudent to reduce the potential consequences of terrorist attacks on pools at some commercial nuclear plants. The statement of task directs the committee to examine the risks of spent fuel storage options and alternatives for decision makers, not to recommend whether any spent fuel should be transferred from pool storage to cask storage. Infact, there may be some commercial plants that, because of pool designs or fuel loadings, may require some removal of spent fuel from their pools. Ifthere is a need to remove spent fuel from the pools it should become clearer once the vulnerability and

-consequence analyses described in the classified report are completed. The committee expects that cost-benefit considerations would be a part of these analyses.

IMPLEMENTATION ISSUES Implementation of the recommendations in Chapters 2-4 will require action and cooperation by a large number of parties. The final chapter of the report provides a brief discussion of two implementation issues that the committee believes are of special interest to Congress: Timing Issues: Ensuring that high-quality, expert analyses are completed in a timely manner; and Communications Issues: Ensuring that the results of the analyses are communicated to relevant parties so that appropriate and timely mitigating actions can be taken. This discussion leads to the following finding and recommendation.

FINDING 5A: security restrictions on sharing of information and analyses are hindering progress in addressing potential vulnerabilities of spent fuel storage to

EXECUTIVE

SUMMARY

I1I terrorist attacks. Current classification and security practices appear to discourage information sharing between the Nuclear Regulatory Commission and industry. They impede the review and feedback processes that can enhance the technical soundness of the analyses being carried out; they make it difficult to build support within the industry for potential mitigative measures; and they may undermine the confidence that the industry, expert panels such as this one, and the public place in the adequacy of such measures.

RECOMMENDATION: The Nuclear Regulatory Commission should improve the sharing of pertinent information on vulnerability and consequence analyses of spent fuel storage with nuclear power plant operators and dry cask storage system vendors on a timely basis.

The committee also believes that the public is an important audience for the

• work being carried out to assess and mitigate vulnerabilities of spent fuel storage facilities. While it would be inappropriate to share all information publicly, more constructive interaction with the public and independent analysts could improve the work being carried out and also increase public confidence in Nuclear Regulatory Commission and industry decisions and actions to reduce the vulnerability of spent fuel storage to terrorist threats.

I INTRODUCTION AND BACKGROUND In the Fiscal Year 2004 Energy and Water Development Conference Report, the U.S. Congress asked the National Academies to provide independent scientific and technical advice on the safety and security1 of commercial spent nuclear fuel storage in the.

United States (see Box 1.1). The Nuclear Regulatory Commission and the Department of Homeland Security jointly sponsored this study, as directed by Congress.

Awareness and concerns about the threat of high-impact terrorism have become acute and pervasive since the attacks on September 11, 2001. The information gathered by the committee during this study led it to conclude that there were indeed credible concerns about the safety and security of spent nuclear fuel storage in the current threat environment.

From the outset the committee believed that safety and security issues must be addressed quickly to determine whether additional measures are needed to prevent or mitigate attacks that could cause grave harm to people and cause widespread fear, disruption, and economic loss. The information gathered during this study reinforced that view. Any concern related to nuclear power plants 2 has added stakes: Many people fear radiation more than they fear exposure to other physical insults. This amplifies the concern over a potential terrorist attack involving radioactive materials beyond the physical injuries it might cause, and beyond the economic costs of the cleanup.

1.1 CONTEXT FOR THIS STUDY The congressional request for this study was prompted by conflicting public claims about the.safety. and security of commercial spent nuclear fuel storage at nuclear power plants. Some have argued that the dense packing used for storing spent fuel in cooling pools at nearly every nuclear power plant does not provide a sufficient safety margin in the event of a pool breach and consequent water 'oss from an accident or terrorist attack.3 In such cases, the potential exists for the fuel most recently discharged from a reactor to heat up sufficiently for its zirconium cladding to ignite, possibly resulting in the release of large amounts of radioactivity to the environment (Alvarez et al., 2003a). The Nuclear Regulatory Commission's own analyses have suggested that such zirconium cladding fires and releases of radioactivity are possible (e.g., USNRC, 2001a).

To reduce the potential for such an event, Alvarez et al. (2003a) suggested that spent fuel more than five years old be removed from the pool and stored in dry casks, and 1 In the context of this study, safety refers to measures that protect spent nuclear fuel storage facilities against failure, damage, human error, or other accidents that would disperse radioactivity in the environment. Security refers to measures to protect spent fuel storage facilities against sabotage, attacks, or theft.

2 Safety and security of reactors at nuclear power plants are outside of the committee's statement of task and have been addressed only where they could not be separated from spent fuel storage. The distinctions between spent fuel storage and operating nuclear power reactors are sometimes blurred in public discussions of nuclear and radiological concerns.

3The committee refers to such occurrences as loss-of-pool-coolant events in this report.

12

INTRODUCTIONAND BACKGROUND 13

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that the remaining younger fuel be rearranged in the pool to allow more space for cooling (see also Marsh and Stanford, 2001; Thompson, 2003). The Nuclear Regulatory Commission staff, the nuclear industry, and some others have argued that densely packed pool storage can be carried out both safely and securely (USNRC, 2003a).

Policy actions to improve the safety and security of spent fuel storage could have significant national consequences. Nuclear power plants generate approximately 20 percent of the electricity produced in the United States. The issue of its future availability and use is critical to our nation's present and future energy security. The safety and security of spent fuel storage is an important aspect of the acceptability of nuclear power. Decisions that affect such a large portion of our nation's electricity supply must be considered carefully, wisely, and with a balanced view.

_. 1.2 STRATEGY TO ADDRESS THE STUDY CHARGES Congress directed the National Academies to produce a classified report that addresses the statement of task shown in Box 1.1 within 6 months and an unclassified summary for unlimited public dissemination within 12 months. This report, which has undergone a security review by the Nuclear Regulatory Commission and found to 4 contain-no classified national security or safeguards information, fulfills the second request.`

The National Research Council of the National Academies appointed a committee of 15 experts to carry out this study. Biographical sketches of the committee members are provided in Appendix B. The committee met six times from February to June 2004 to gather information and complete its classified report. The committee met again in August, October, and November 2004 and in January 2005 to develop this public report.

Details on the information-gathering sessions and speakers are provided in Appendix A. Most of the information-gathering sessions were not open to the public because they involved presentations and discussions of classified information. The committee recognized, however, that important contributions to this study could be made by industry representatives, independent analysts, and the public, so it scheduled open, unclassified 4 The classified report was briefed to the agencies and Congress on July 15, 2004.

14 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE sessions at three of its meetings to obtain comments from interested organizations and individuals. Public comments at these meetings were encouraged and considered.

Subgroups of the committee visited several nuclear power plants to learn first-hand how spent fuel is being managed in wet and dry storage: the Dresden and Braidwood Nuclear Generating Stations in Illinois, which are owned and operated by Exelon Nuclear Corp.; the Indian Point Nuclear Generating Station in New York, which is owned and operated by ENTERGY Corp.; and the Palo Verde Nuclear Generating Station in Arizona, which is operated by Arizona Public Service Corp. A subgroup of committee members also traveled to Germany to visit spent fuel storage installations at Ahaus and Lingen and to talk with experts about the safety and security of German spent fuel storage. The German government has been concerned about security for a long time, and the German nuclear industry has made adjustments to spent fuel storage designs and operations that reduce their vulnerability to accidents and terrorist attacks. A summary of the trip to Germany is provided in Appendix C.

The statement of task for this study directed the committee to examine both the safety and the security of spent fuel storage. It is important to recognize that these are two sides of the same coin in the sense that any event that results in the breach of a spent fuel pool or a dry cask, whether accidental or intentional, has the potential to release radioactive material to the environment. The committee therefore focused its limited time on understanding two issues: (1) Under what circumstances could pools or casks be breached?

And (2) what would be the radioactive releases from such breaches?

The initiating events that could lead to the accidentalbreach of a spent fuel pool are well known: A large seismic event or the accidental drop of a cask on the pool wall that could lead to the loss of pool coolant. The condition that could lead to an accidental breach of a dry storage cask is similarly well known: an accidental drop of the cask during handling operations. Current Nuclear Regulatory Commission regulations are designed to prevent such accidental conditions by imposing requirements on the design and operation of spent fuel storage facilities. These regulations have been in place for decades and have so far been effective in preventing accidental releases of radioactive materials from these facilities into the environment.

The initiating events that could lead to the intentionalbreach o6f a spent fuel pool or dry storage cask are not as well understood. The Nuclear Regulatory Commission has had long-standing requirements in place to deal with radiological sabotage (included in the "design basis threat"; see Chapter 2), but the September 11, 2001, terrorist attacks provided a graphic demonstration of a much broader array of potential threats. As described in the following chapters, the Nuclear Regulatory Commission is currently sponsoring studies to better understand the potential consequences of such terrorist attacks on spent fuel storage facilities.

Early on in this study, the committee made a judgment that it should focus most of its attention concerning such initiating events on the security aspects of its task statement.

Many of the phenomena that follow an initiating event (e.g., loss of pool coolant or cask breach) would be the same whether it arose from an accident or terrorist attack, as noted previously. While the mitigation strategies for such events might be similar, they would require different kinds of preparation.

Given the relatively short time frame for this study, the committee focused its efforts

INTRODUCTION AND BACKGROUND 15 on performing a critical review of the security analyses that have been carried out by the NuclearRegulatory Commission and its contractors, the Department of Homeland Security, industry (i.e., EPRI, formerly named the Electric Power Research Institute; ENTERGY Corp.;

and dry cask vendors), and other independent experts to determine if they are objective, complete, and credible. The committee could only perform limited independent safety and security analyses based on the information it gathered.

The committee made many requests for information from the Nuclear Regulatory Commission, its Sandia National Laboratories contractor, and other organizations and individuals, often with little advance notice. For the most part, all parties responded well to these requests. The committee was able to access experts who could answer its technical questions and was pleased with the cooperation and information it received during its visits to spent fuel storage facilities. This cooperation was essential in enabling the committee to complete its task within the requested six-month timeframe.

The committee was forced to circumscribe some aspects of its examinations, however, due to time and/or information constraints. In particular, the committee did not pursue in-depth examinations of the following topics:

" Human factors issues involved in responding to terrorist attacks on spent fuel storage. These include surveillance activities to identify potential threats (both inside and outside the plant); the response of security forces; and the preparation of plant personnel to deploy mitigative measures in the event of an attack..

• The behavior of radioactive material after it enters the environment from a spent fuel pool or dry cask. The committee assumed that any large release of radioactivity from a spent fuel storage facility would be problematic even in the absence of knowledge of how it would disperse in the environment. The committee instead focused its efforts on understanding how much radioactive material would be released, if any, in the case of an attack.

• The economic consequences of potential terrorist attacks, except insofar as noting the possible magnitude of cleanup costs after a catastrophic release of radioactivity.

• The costs of potential measures to mitigate spent fuel storage vulnerabilities. The committee understands that the Nuclear Regulatory Commission would include cost-benefit considerations in decisions to impose any new requirements on industry for such measures.

The committee also did not examine the potential vulnerability of commercial spent fuel while being transported. That topic is not only outside of the committee's task, but there is another National Academies study currently underway to examine transportation issues.5 Because most of the studies on spent fuel storage vulnerabilities undertaken for the Nuclear Regulatory Commission are still in progress, the committee was not able to review completed technical documents. Instead, the committee had to rely on presentations by and discussions with technical experts. The committee does not believe that these difficulties prevented it from developing sound findings and recommendations from the information it 5 Committee on Transportation of Radioactive Waste. See http://national-academies.orgltransportofradwaste. That committee's final report is now planned for completion in the late summer of 2005.

16 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE did receive. The committee was able to draw upon other information sources both domestic and foreignr including the experience and expertise of its members, to fill some of the information gaps.

1.3 REPORT ROADMAP The sections that follow in this chapter provide background on storage of spent nuclear fuel, which may be helpful to non-experts in understanding the issues discussed in the following chapters. The other chapters are organized to explicitly address the four charges of the committee's statement of task:

" Chapter 2 addresses the last charge to the committee to "explicitly consider the risks of terrorist attacks on these materials and the risk these materials might be used to construct a radiological dispersal device."

" Chapter 3 addresses the first charge to the committee to examine the "potential safety and security risks of spent nuclear fuel presently stored in cooling pools at commercial reactor sites."

" Chapter 4 addresses the second and third charges to examine the "safety and security advantages, if any, of dry cask storage versus wet pool storage at these reactor sites" and the "potential safety and security advantages, if any, of dry cask storage using various single-, dual-, and multi-purpose cask designs."

• Chapter 5 concerns implementation of the recommendations in this report, specifically concerning timing and communication issues.

The appendixes provide supporting information, including a glossary and acronym list, descriptions of the committee's meetings, and biographical sketches of the committee members.

1.4 BACKGROUND

ON SPENT NUCLEAR FUEL AND ITS STORAGE This section is provided for readers who are not familiar with the technical features of spent nuclear fuel and its storage. Other readers should skip directly to Chapter 2.

Spent nuclear fuel is fuel that has been irradiated or "burned" in the core of a nuclear reactor. In power reactors, the energy released from fission reactions in the nuclear fuel heats water 7 to produce steam that drives turbines to generate electricity. Spent nuclear fuel from non-commercial reactors (such as research reactors, naval propulsion reactors, and plutonium production reactors) is not considered in this study.

1.4.1 Nuclear Fuel Almost all commercial reactor fuel in the United States is in the form of solid, cylindrical pellets of uranium dioxide. The pellets are about 0.4 to 0.65 inch (1.0 to 1.65 centimeters) in length and about 0.3 to 0.5 inch (0.8 to 1.25 centimeters) in diameter. The For example, the aforementioned visits to Lingen and Ahaus, in Germany.

A different coolant can be used, but all power reactors now operating in the United States are water cooled.

INTRODUCTION AND BACKGROUND 17 pellets are loaded into tubes, called fuel cladding, made of a zirconium metal alloy, called zircaloy. A loaded tube, which is typically 11.5 to 14.75 feet (3.5 to 4.5 meters) in length, is called a fuel rod (also referred to as a fuel pin or fuel element). Fuel rods are bundled together, with a 0.12 to 0.18 inch (0.3 to 0.45 centimeter) space left between each for coolant to flow, to form a square fuel assembly (see FIGURE 1.1) measuring about 6 to 9 inches (15 to 23 centimeters) on a side.

Typical fuel assemblies for.boiling water nuclear reactors (BWRs) hold 49 to 63 fuel rods, and fuel assemblies for pressurized water nuclear reactors (PWRs) hold 164 to 264 8

fuel rods. Depending on reactor design, typically between 190 and 750 assemblies, each weighing from 275 to 685 kg (600 to 1500 pounds), make up a power reactor core. New fuel assemblies (i.e., those that have not been irradiated in a reactor) do not require special cooling or radiation shielding; they can be moved with a crane in open air. Once in the reactor, however, the fuel undergoes nuclear fission and begins to generate the radioactive fission products 'and activation products that require shielding and cooling.

The uranium oxide fuel essentially is composed of two isotopes of uranium: Initially, about 3-5 percent 9 by weight is fissile uranium (uranium-235), which is the component that sustains the fission chain reaction; and about 95-97 percent is uranium-238, which can capture a neutron to produce fissile plutonium and other radioactive heavy isotopes (actinides). Each fission event, whether in uranium or plutonium, releases energy and neutrons as the fissioning nucleus splits into two (and infrequently three) radioactive fragments, called fission products.

When the fissile material has been consumed to a level where it is no longer economically viable. (typically 4.5 to 6 years of operation for current fuel designs), the fuel is considered spent and is removed from the reactor core. Spent fuel assemblies are highly radioactive. The decay of radioactive fission products and other constituents generates heat (called decay heat) and penetrating (gamma and neutron) radiation. Therefore cooling, shielding, and remote handling are required for spent nuclear fuel.

The amount of heat and radiation generated by a spent fuel assembly after its removal from a reactor depends on the number of fissions that have occurred in the fuel, called the burn-up, and the time that has elapsed since the fuel was removed from the reactor. The rate of decay-heat generation by spent reactor fuel and how it will change with time after the fuel is removed from the reactor can be calculated. The results of an example calculation are shown in FIGURE 1.2.

At discharge from the reactor, a spent fuel assembly generates on the order of tens of kilowatts of heat. Decay-heat production diminishes as very short-lived radionuclides decay away, dropping heat generation by a factor of 100 during the first year;, dropping by another factor of 5 between year one and year five; and dropping about 40 percent between year five and year ten (see FIGURE 1.2). Within a year of discharge from the reactor, decay-heat production in spent nuclear fuel is dominated by four radionuclides: Ruthenium-1 06 (with a 372.6-day half-life), cerium-144 (284.4-day half-life), cesium-137 (30.2-year half-life),

8Technical specifications for the fuel assemblies are taken from the American National Standard 1988).

document for pool storage of spent nuclear fuel (American Nuclear Society,

' With only a few exceptions, commercial nuclear power reactors in the United States have been fueled with low-enriched uranium, that is, less than 20 percent of the uranium is uranium-235.

Uranium found in nature has about 0.71 percent uranium-235 by weight.

18 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE

• Fuel element. Fuel a-sembly FIGURE 1.1 Fuel rods, also called fuel pins or elements, are bundled together into fuel assemblies as shown here. This fuel assembly is for a PWR reactor. SOURCE: Duderstadt and Hamilton (1976; Figure 3-7).

and cesium-1 34 (2.1-year half-life) and their short-lived decay products contribute nearly 90 percent of the decay heat from a spent fuel assembly.

Longer-lived radionuclides persist in the spent fuel even as the decay heat drops further. Cesium-1 37 decays to barium-1 37, emitting a beta particle and a high-energy gamma ray. The cesium-1 37 half-life of 30.2 years is sufficiently long to ensure that this radionuclide will persist during storage. It and other materials present in the fuel will form small particles, called aerosols, in a zirconium cladding fire.

Shorter-lived radionuclides decay away rapidly after removal of the spent fuel from the reactor. One of these is iodine-1 31, which is of particular concern in reactor core accidents because it can be taken up in large quantities by the human thyroid. This radionuclide has a half-life of about 8 days and typically persists in significant quantities in spent fuel only on the order of a few months.

INTRODUCTION AND BACKGROUND 19 10000000 e Actinides 1000000.

oAo Fission products Total M 100000 10000.

a.

• 0 1000

,.. 100 10 Time since discharge from reactor FIGURE 1.2 Decay-heat power for spent fuel (measured in watts per metric ton of uranium) plotted on a logarithmic scale as a function of time after reactor discharge. Note that the horizontal axis is a data series, not a scale. SOURCE: Based on data from USNRC (1984).

1.4.2 Storage of Spent Nuclear Fuel Storage. technologies for spent nuclear fuel have three primary objectives:

" Cool the fuel to prevent heat-up to high temperatures from radioactive decay.

• Shield workers and the public from the radiation emitted by radioactive decay in the spent fuel and provide a barrier for any releases of radioactivity.

" Prevent criticality accidents (uncontrolled fission chain reactions).

After the fuel assemblies are unloaded from the reactor they are stored in water pools, called spent fuel pools. The water in the pools provides radiation shielding and cooling and captures all but noble gas radionuclides in case of fuel rod leaks.1' The geometry of the fuel and neutron absorbers (such as boron, hafnium, and cadmium),within the racks that hold the spent fuel or in the cooling water help prevent criticality events.1 1 The water in the pool is circulated through heat exchangers for cooling and ion exchange filters to capture any radionuclides and other contaminants that get into the water. Makeup water is also added to the pool to replace pool water lost to evaporation. The operation of the pumps and heat exchangers is especially important during and immediately after reactor 10 If the cladding in the fuel rods is breached some radioactive materials will be released into the pool.

11 See the Glossary (Appendix E) for a definition of criticality. Most of the fuel's capacity for sustaining criticality is expended in the reactor as the uranium and plutonium are fissioned.

20 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE refueling operations, because this is when larger quantities of higher heat-generating spent fuel are placed into the pool.

Current U.S. regulations require that spent fuel be stored in the power plant's fuel pool for at least one year after its discharge from the reactor before being moved to dry storage. After that time the spent fuel can be moved, but only with active cooling. Active cooling is generally necessary for about three years after the spent fuel is removed from the reactor core (USNRC, 2003b).

When a spent fuel pool is filled to capacity, older fuel, which has lower decay-heat, is moved to other pools or placed into dry casks. Heat generated in the loaded dry casks is removed by air convection and thermal radiation. The cask provides shielding of penetrating radiation and confinement of the radionuclides in the spent fuel. As with pool storage, criticality control is accomplished by placing the fuel in a fixed geometry and separating individual fuel assemblies with neutron absorbers. Standard industry practice is to place in dry storage only spent fuel that has cooled for five years or more after discharge from the reactor.12 Most spent fuel in wet or dry storage is located at nuclear power plant sites (i.e.,

on-site storage).

There are significant differences in the design and construction of wet and dry storage installations at commercial nuclear power plants. The characteristics depend on the type of the nuclear power plant, the age of the spent fuel storage installation, or the type of dry casks used. The design and features of spent fuel pools and dry storage facilities are discussed in Chapters 3 and 4, respectively.

1.4.3 Spent Fuel Inventories As of 2003, approximately 50,000 MTU (metric tons of uranium) of spent fuel have been generated over the past four decades in the United States. A typical nuclear power plant generates about 20 MTU per year. The entire U.S. nuclear industry generates about 2000 MTU per year.

Of the approximately 50,000 MTU of commercial spent fuel in the United States, 43,600 MTU are currently stored in pools and 6200 MTU are in dry storage. Pool storage exists at all 65 sites with operating commercial nuclear power reactors13 and at 8 sites where commercial power reactors are no longer operating (i.e., they have been shut down or decommissioned) (FIGURE 1.3). Additionally, there is an away-from-reactor spent fuel pool operating at the G.E. Morris Facility in Illinois (see Appendix D).

Of the spent fuel in dry storage, 4500 MTU are in storage at 22 sites with operating commercial nuclear power reactors, and 1700 MTU are in storage at 6 sites where the commercial reactors are no longer operating. An additional dry-storage facility is operated by the federal government at the Idaho National Laboratory. It stores most of the damaged fuel from the Three Mile Island Unit 2 reactor accident.

12 Fuel aged as little as three years could be stored in passively cooled casks, but fewer assemblies could be accommodated in each cask because of the higher heat load.

13 There are 103 operating commercial nuclear power reactors in the United States. Many sites have more than one operating reactor.

INTRODUCTION AND BACKGROUND 21 FIGURE 1.3 Locations of spent fuel storage facilities in the United States.

TABLE 1.1 provides a listing of the 30 operating Independent Spent Fuel Storage Installations (ISFSis 14 ) in the United States. These ISFSIs include the dry storage facilities at operating and shutdown commercial power reactor sites as well as the storage facilities at the Morris and Idaho sites, as described above. The committee did not examine the Morris and Idaho facilities as part of this study. At-reactor pool storage is not considered to be an ISFSI because it operates under the power reactor license.

1.4.4 History of Spent Fuel.Storage Spent fuel pools at commercial nuclear power plants were not designed to accommodate all the fuel used during the operating lifetime of the reactors they service.

Most commercial power plants were designed with small pools under the assumption that-.

fuel would be cooled for a short period of time after discharge from the reactor and then be sent offsite for recycling (i.e., reprocessing).' 5 A commercial reprocessing industry never developed, however, for the reasons discussed in Appendix D. Newer power plants were designed with larger pool storage capacities. Even plants with larger-capacity pools will run out of pool space if they operate beyond their initial 40-year licenses. In 2000, the nuclear power industry projected that roughly three or four plants per year would run out of needed storage space in their pools without additional interim storage capacity (see FIGURE 1.4).

Another development that logically could reduce the demand for storage of spent nuclear fuel at the sites of power plants is the availability of a geologic repository for 14 An ISFSI is a facility for storing spent fuel in wet pools or dry casks and is defined in Title.10, Part 72 of the Code of Federal Regulations.

15 Residual uranium-235 and plutonium in the spent fuel would be recovered for the manufacture of new fuel. The waste products in the fuel, principally the fission products, would be immobilized in solid matrices and stored for eventual disposal.

22 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE TABLE 1.1: Operating ISFSIs in the United States as of July 2004 Name Location Palo Verde Arizona Arkansas Nuclear One Arkansas Rancho Seco California San Onofre California Diablo Canyon California Fort St. Vrain 1 Colorado Edwin L. Hatch Georgia DOE-INL 2 Idaho G.E. Morris 3 Illinois Dresden Illinois Duane Arnold Iowa Maine Yankee Maine Calvert Cliffs Maryland Big Rock Point Michigan Palisades Michigan Prairie Island Minnesota Yankee Rowe Massachusetts Oyster Creek New Jersey JA. FitzPatrick New York McGuire North Carolina Davis-Besse Ohio Trojan Oregon Susquehanna Pennsylvania Peach Bottom Pennsylvania Robinson South Carolina Oconee South Carolina North Anna Virginia Surry Virginia Columbia Gen. Station Washington Point Beach Wisconsin NOTES:

!The Fort St. Vrain ISFSI stores fuel from a commercial gas-cooled reactor. The facility is operated by the Department of Energy.

2The DOE-INL facility stores fuel from the Three-Mile Island Unit

. 2 reactor. The facility is operated by the Department of Energy.

3The G.E. Morris ISFSI is a wet storage facility.

SOURCES: Data from the USNRC (2004).

INTRODUCTION AND BACKGROUND 23 60 50.

C 40 0.S o

I.-.

30.4 ro Number of plants affected nsk Cumulatora e total

= 20-z 0

2002 2003 20D4 2005 EDFiTIr1 2006 2007 2008 2009 2010 2011 2013 2015 2016 7i".-,-

2017 2024 Year FIGURE 1.4 Projection of the number of commercial nuclear power plants that will run out of needed space in their spent fuel pools in coming years if they do not add interim storage, These data, looking only at plants that did not already use dry cask storage, were provided to the Nuclear Regulatory Commission in 2000. SOURCE: USNRC (2001b).

disposal of spent nuclear fuel. But a nuclear waste repository is not expectedto be in operation until at least 2010, and even then it will take several decades for all of the spent fuel to be shipped for disposal. .Thus, onsite storage of spent fuel is likely to continue for at least several decades.

Power plant operators have made two changes in spent fuel storage procedures to increase the capacity of onsite storage. First, starting in the late 1970s, plant operators began to install high-density racks that enable more spent fuel to be stored in the pools. This has increased storage capacities in some pools by up to about a factor of five (USNRC, 2003b). Second, as noted above, many plant operators have moved older spent fuel from the pools into dry cask storage systems (see Chapter 4) or into other pools when available to make room for freshly discharged spent fuel and to maintain the capacity for a full-core offload. 16 The original spent fuel racks, sometimes called "open racks," were designed to store spent fuel in an open array, with open vertical and lateral channels between the fuel assemblies to promote water circulation. The high-density storage racks eliminated many of the channels so that the fuel assemblies could be packed closer together (FIGURE 1.5).

This configuration does not allow as much water (or air circulation in loss-of-pool-coolant events) through the spent fuel assemblies as the original open-rack design.

16 Although not required by regulation, it is standard practice in the nuclear industry to maintain enough open space in the spent fuel pool to hold the entire core of the nuclear reactor. This provides an additional margin of safety should the fuel have to be removed from the reactor core in an emergency or for maintenance purposes.

24 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Several nuclear utilities have already submitted license applications to the Nuclear Regulatory Commission to build 16 new ISFSIs. Among the potential new ISFSIs, a consortium of utilities has submitted a license for a private fuel storage facility (PFS) in Utah for interim dry storage of up to 40,000 metric tons of spent fuel.

Most or all pools store some spent fuel that has aged more than five years after discharge from the reactor, and so could be transferred to dry-cask storage. The amount that could be transferred depends on plant-specific information such as pool size and configuration, operating history of the reactor, the enrichment and bum-up level in the fuel, and availability of an ISFSI.

Empty Cell

_BWR Assembly Boraflex Panel in Steel Wrapper Coolant Flow Flow Holes (4)

(Through the rack support footing)

FIGURE 1.5 Dense spent fuel pool storage racks for BWR fuel. This cross-sectional illustration shows the principal elements of the spent fuel rack, which sits on the bottom of the pool. SOURCE: Nuclear Regulatory Commission briefing materials (2004).

2 TERRORIST ATTACKS ON SPENT FUEL STORAGE This chapter addresses the final charge to the committee to "explicitly consider the risks of terrorist attacks on [spent fuel] and the risk these materials might be used to construct a radiological dispersal device." The concept of risk as applied to terrorist attacks underpins the entire statement of task for this study. Therefore, the committee addresses this final charge first to provide the basis for addressing the remainder of the task statement.

The chapter is organized into the following sections:

• Background on risk.

• Terrorist attack scenarios.

" Risks of terrorist attacks on spent fuel storage facilities.

• Findings and recommendations.

2.1 BACKGROUND

ON RISK "Risk" is a function of three factors (Kaplan and Garrick, 1981):

" The scenariodescribing the undesirable event.

• The probabilitythat the scenario will occur.

• The consequences if the scenario should occur.

In the context of the present report, a scenariodescribes the modes and mechanisms of a possible terrorist attack against a spent fuel storage facility. For example, a scenario might involve a suicide attack with a hijacked civilian airliner. Another might involve a ground assault with a truck bomb. Several such scenarios are described later in this chapter and discussed in more detail in the committee's classified report.

Probabilityis a dimensionless quantity that expresses the likelihood that a given scenario will occur over a specified time period. If the occurrence of a scenario is judged to be impossible, it would have a probability of 0.0. On the other hand, if the scenario were judged to be certain, it has a probability of 1.0. A scenario that had a.50 percent chance of occurrence during the period contemplated would have a probability of 0.5.

Consequences describe the undesirable results if the scenario were to occur. For example, a terrorist attack on a spent fuel storage facility could release ionizing radiation to the environment.1 The exposure of the public to this radiation could have both deterministic and stochastic effects. The former would occur from short-term exposures to very high doses of ionizing radiation, the latter to smaller doses that might have no immediate effects 1Terrorist scenarios and consequences are being described here for the sake of illustration. One should not conclude from this description that the committee believes that such consequences would necessarily occur as the result of a terrorist attack on a spent fuel storage facility.

25

26 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE but could result in cancer induction some years or decades later.2 Consequences also could be described in terms of economic damage. These could arise, for example, from the loss of use of the facility and surrounding areas or costs to clean up those areas. There also could be severe psychological consequences that could drive changes in public acceptance of commercial nuclear energy.

The quantitative expression for the risk of a particular scenario, for example a suicide terrorist attack with a hijacked airliner, is Risk airlinerattack =- Probability aidiner attack X Consequences airliner attack (1)

The total risk would be the sum of the risks for all possible independent attack scenarios. For example, if a spent fuel storage facility was determined to be vulnerable to attacks using airliners, truck bombs, and armed assaults, the total risk would be calculated as Risk total "- Risk airliner attack + Risk truck bomb attack + Risk armed assault attack (2)

Such equations are routinely used to calculate the risks of various industrial accidents, including accidents at nuclear power plants, through a process known as probabilisticrisk assessment. Each accident is assigned a numerical probability based on a careful analysis of the sequence of failures (e.g., human or mechanical failures) that could produce the accident. The consequences of such accidents are typically expressed in terms of injuries, deaths, or economic losses.

It is possible to estimate the risks of industrial accidents because there are sufficient experience and data to quantify the probabilities and consequences. This is not the case for terrorist attacks. To date, experts have not found a way to apply these quantitative risk equations to terrorist attacks because of two primary difficulties: The first is to develop a complete set of bounding scenarios for such attacks; the second is to estimate their probabilities. These depend on impossible-to-quantify factors such as terrorist motivations, expertise, and access to technical means. 3 They also depend on the effectiveness of measures that might prevent or mitigate such attacks.

In the absence of quantitative information on risks, one could attempt to make qualitative risk comparisons. Such comparisons could estimate, for example, the relative risks of attacks on spent fuel storage facilities versus attacks on commercial nuclear power reactors or other critical infrastructure such as chemical plants.'Although a comparison of such risks is beyond the scope of this study, the committee recognizes that policy decisions about spent fuel storage may need to take into account such comparative risk issues, 2 Such cancers would likely not be directly traceable to the radiation dose received from a terrorist attack and would likely be indistinguishable from the large population of cancers that result from other causes.

3 Political scientists and counter-terror specialists have argued whether terrorists seek headlines, casualties, or both (e.g., Jenkins 1975, 1985). The September 11, 2001, attacks in the United States and the March 11, 2004, attacks in Spain demonstrate that some terrorists, particularly those of al-Qaida and its allies, intend to commit mass murder and/or mass economic disruption, both of which may have important political consequences. Further information about the motivation of terrorists is provided in NRC (2002).

TERRORIST A TTACKS ON SPENT FUEL STORAGE 27 especially for decisions regarding the expenditure of limited societal resources to address terrorist threats.

The 2002 National Research Council report Making the Nation Safer: The Role of Science and Technology in Countering Terrorismframed this issue as follows (NRC, 2002,

p. 43):

The potential vulnerabilities of NPPs [nuclear power plants] to terrorist attack seem to have captured the imagination of the public and the media, perhaps because of a perception that a successful attack could harm large populations and have severe economic and environmental consequences.

There are, however, many other types of large industrial facilities that are potentially vulnerable to attack, for example, petroleum refineries, chemical plants, and oil and liquefied natural gas supertankers. These facilities do not have the'robust construction and security features characteristic of NPPs, and many are located near highly populated urban areas.

Groups seeking to carry out high-impact terrorism will likely choose targets that have a high probability of being attacked successfully. 4 Ifsuccess is measured by the number of people killed and injured or the permanent destruction of property, then spent fuel storage facilities may not make good terrorist targets owing to their relatively robust construction (see Chapters 1 and 3) and security. Industrialized societies like the United States provide terrorists a large number of "soft" (i.e., unprotected) targets that could be attacked more easily with greater effect than spent fuel storage facilities. These include chemical plants, refineries, transportation systems, and other facilities where large numbers of people gather (see NRC, 2002).

On the other hand, there are other success criteria that might influence a terrorist's decision to attack a "hard" (i.e., robust or well protected) target such as a commercial nuclear power plant and its spent fuel storage facilities. Such attacks could spread panic and shut down the power plant for an extended period of time even with no loss of life.

Moreover, an attack that resulted in the release of radioactive material could threaten the viability of commercial nuclear power.

These considerations led the committee to conclude that it could not address its charge using quantitative and comparative risk assessments. The committee decided instead to examine a range of possible terrorist attack scenarios in terms of (1) their potential for damaging spent fuel pools and dry storage casks; and (2) their potential for radioactive material releases. This allowed the committee to make qualitative judgments about the vulnerability of spent fuel storage facilities to terrorist attacks and potential measures that could be taken to mitigate them.

4 This point was made to the committee in a briefing by the Department of Homeland Security, where "success" means that the terrorist was able to achieve the goals of the attack, whatever they might be.

28 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 2.2 TERRORIST ATTACK SCENARIOS It is possible to imagine a wide range of terrorist attacks against spent fuel storage facilities. Each would have a range of potential consequences depending on the characteristics of the attack and the facility being targeted as well as any post-attack mitigative actions to prevent or reduce the release of radioactive material. The committee focused its discussions about terrorist attacks around the concept of a maximum credible scenario-that is, an attack that is physically possible to carry out and that produces the most serious potential consequences within a given class of attack scenarios.

The following example illustrates the concept: One of the scenario classes considered by the committee in this chapter involves suicide attacks against spent fuel storage facilities with civilian passenger aircraft. The physics of such attacks are well understood: In general, heavier and higher-speed aircraft produce greater impact forces than lighter and slower aircraft, all else being equal. Consequently, the maximum credible scenario for suicide attacks involving civilian passenger aircraft would utilize the largest civilian passenger aircraft widely used in the United States flying at maximum cruising speed and hitting the facility at its most vulnerable point. Such an attack provides an upper bound to the damage that could be inflicted by this type of aircraft attack.

The maximum credible scenario is particularly useful for obtaining a general understanding of the damage that could be inflicted, but it would not necessarily apply to every spent fuel storage facility. To be judged a "credible" scenario, the terrorist must be able to successfully carry it out as designed-for example, to hit a spent fuel storage facility with the largest civilian aircraft at its most vulnerable point. This would rule out attacks that are physically impossible, such as flying a large civilian aircraft into a facility that is located below ground level or protected by surrounding hills or buildings. This also would riule out attacks involving weapons that are not available to terrorists (e.g., aircraft-launched weapons such as "bunker-buster" bombs or nuclear weapons).

This is not intended, however, to rule out attacks that are judged to have a low probability for success simply because terrorists might lack the skill and knowledge or luck to carry them out. In fact, if the consequences of such attacks were severe, policy makers might still decide that prudent mitigating actions should be taken regardless of their low probabilities of occurrence. 5 This might be especially true if quick, inexpensive fixes could be implemented. The main benefit of analyzing the maximum credible scenario is that it provides decision makers with a better characterization of the full range of potential consequences so that sound policy judgments can be made.

The analyses carried out for the Nuclear Regulatory Commission (described in the committee's classified report) do not consider maximum credible scenarios. Instead, the analyses employ reference scenariosthat are based either on the characteristics of previous terrorist attacks or on qualitative judgments of the technical means and methods that might be employed in attacks against spent fuel storage facilities. Although such reference scenarios are useful for gaining insights on potential consequences of terrorist attacks, they The Department of Energy, for example, routinely examines the consequences of very low probability events involving nuclear weapons safety and security; see, for example, AL 56XB Development and Production Manual published by the U.S. Department of Energy, National Nuclear Security Administration. See http://prp.lanI.gov/documents/ldp_manual.asp.

TERRORISTA TTACKS ON SPENT FUEL STORAGE 29 are not necessarily bounding. This becomes important when the reference scenario attack results in damage to a facility that verges on failure.

The committee prefers a maximum credible scenario approach for one important reason: It believes that terrorists who choose to attack hardened facilities like spent fuel storage facilities would choose weapons capable of producing maximum destruction. Of course, once the consequences of such attacks are known, an element of expert judgment is required to determine whether such attacks have a high likelihood of being carried out as designed. Such judgment is especially important when making policy decisions about actions to reduce the vulnerabilities of facilities to such attacks.

The consequences of terrorist attacks can be described in terms of either maximum credible releases or best-estimate releases.The former describes the largest releases of radioactive matdrial following an attack based on quantitative analytical models (e.g., the MELCOR compUter code described in Chapter 3). The latter describes the median estimates from such models. In both cases, the estimates may not account for mitigative actions that could be taken after an attack to reduce or even eliminate releases. The Nuclear Regulatory Commission analyses reviewed by the committee in its classified report are best-estimate releases for various terrorist attack scenarios. The estimates in NUREG-1738 (USNRC, 2001a) and Alvarez et al. (2003a), on the other hand, describe maximum-credible to worst-case releases.6 The committee considered four classes of terrorist attack scenarios in this study:

• Air attacks using large civilian aircraft or smaller aircraft laden with explosives.

" Ground attacks by groups of well-armed and well-trained individuals.

• Attacks involving combined air and land assaults.

• Thefts of spent fuel for use by terrorists (including knowledgeable insiders) in radiological dispersal devices.

The committee devoted time at its meetings discussing these scenarios. It also received briefings on possible scenarios from Nuclear Regulatory Commission staff and suggestions for scenarios from the Department of Homeland Security (DHS), other experts, and the public. Some scenarios were dismissed by the committee as not credible. An example of such a scenario is an attack on a spent fuel storage facility with a nuclear weapon. Such weapons would be relatively difficult7 for terrorists to build or steal. Even if such a weapon could be obtained, the committee can think of no reason that it would be used against a spent fuel storage facility rather than another target. There are easier ways to attack spent fuel storage facilities, as discussed in the classified report, and there are more attractive targets for nuclear weapons, for example, large population centers.

6 Worst-case releases are based on the most unfavorable conditions that could occur in a given scenario, regardless of whether those conditions were physically realistic. For example, a worst-case estimate of the radionuclide releases from an attack on a spent fuel pool might assume that all of the volatile radionuclides contained in the spent fuel would be released, even ifquantitative analytical models showed that such releases were very unlikely to occur.

7Difficult but certainly not impossible. See Chapter 2 in NRC (2002).

30 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Given the experience of September 11, 2001, and the attacks that have occurred in other parts of the world, it is clear to the committee that the ability of the most capable terrorists to carry out attacks is limited only by their access to technical means. It is probably not limited by the ability of terrorist organizations to recruit or train attackers or bring them and any needed equipment into the United States-if indeed they are not already here.

Moreover, the demonstrated willingness of terrorists to carry out suicide attacks greatly expands the scenarios that need to be considered when analyzing potential threats.

As is discussed in some detail in Chapters 3 and 4, the facilities used to store spent fuel at nuclear power plants are very robust. Thus, only attacks that involve the application of large energy impulses or that allow terrorists to gain interior access have any chance of releasing substantial quantities of radioactive material. This further restricts the scenarios that need to be considered. For example, attacks using rocket-propelled grenades (RPGs) of the type that have been carried out in Iraq against U.S. and coalition forces would not likely be successful if the intent of the attack is to cause substantial damage to the facility.

Of course, such an attack would get the public's attention and might even have economic consequences for the attacked plant and possibly the entire commercial nuclear power industry.

The threat scenarios summarized in this chapter are based on documents provided to the committee, briefings received at committee meetings, and the committee's own expert 8

judgment. Further overview and information on nuclear and radiological threats in general can be found in the NRC (2002) report and references therein.

2.2.1 Air Attacks The September 11, 2001, attacks 9 demonstrated that terrorists are capable of successfully attacking fixed infrastructure with large civilian jetliners. The security of civilian passenger airliners has been improved since these attacks were carried out, and the vulnerability of civilian passenger aircraft to highjacking has been reduced. Nevertheless, the committee judges, based on the evidence made available to it during this study, that attacks with civilian aircraft remain a credible threat. Such aircraft are used routinely in freight and charter services, and large numbers of such aircraft enter the United States from other countries each day. Improvements to ground security or cargo inspection would likely not eliminate the threat posed by an air crew willing to stage a suicide attack with a chartered air freighter.

Although the September 11, 2001, attacks utilized Boeing 757 and 767 airliners, larger aircraft (Boeing 747, 777; Airbus 340) are in routine use around the world, and an even larger aircraft (Airbus 380) is entering production. Assaults by such large aircraft could impart enormous energy impulses to spent fuel storage facilities. Additionally, attacks with 8The committee found limited information in the open literature on various scenarios for terrorist attacks on nuclear plants and their spent fuel storage facilities.

9 The al-Qaida terrorist organization hijacked and crashed two Boeing 767 airliners into Towers 1 and 2 of the World Trade Center building in New York and a Boeing 757 airliner into the Pentagon building in Arlington, Virginia. A second Boeing 757, which was believed to be targeted either on the White House or the U.S. Capitol (see National Commission on Terrorist Attacks Upon the United States, Staff Statement No. 16 [Outline of the 9/11 Plot], pages 18-19) crashed in an open field near Jennerstown, Pennsylvania.

TERRORIST A TTACKS ON SPENT FUEL STORAGE 31 aircraft carrying large fuel loads could produce fires that would greatly complicate rescue and recovery efforts.

Previous studies on aircraft crash impacts (Droste et al., 2002; Lange et al., 2002; HSK, 2003; RBR Consultants, 2003; Thomauske, 2003) suggest that the consequences of a heavy aircraft crash on a nuclear installation depend on factors such as the following:

" Type and design of the aircraft.

• Speed of the aircraft.

" Fuel loading of the aircraft and total weight at impact.

• Angle-of-attack and point-of-impact on the facility.

• Construction of the facility.

10

", Location of the target with respect to ground level (i.e., below or above grade).

• The presence of surrounding buildings and other obstacles (e.g., hills, transmission lines) that might block certain potential flight paths into the facility.

In other words, the consequences of such attacks are scenario- and plant-design specific. It is not possible to make any general statements about spent fuel storage facility vulnerabilities to air attacks that would apply to all U.S. commercial nuclear power plants.

U.S. commercial nuclear power plants are not required by the Nuclear Regulatory Commission to defend against air attacks. The Commission believes that it is the responsibility of the U.S. govemment to implement security measures to prevent such attacks. The commercial nuclear industry shares this view. The Nuclear Regulatory Commission staff informed the committee that the Commission has directed power plant operators to take steps to reduce the likelihood of serious consequences should such attacks occur. The staff also informed the committee that the Commission may issue additional directives once the vulnerability analyses it is sponsoring at Sandia National Laboratories are completed. These analyses are described in the committee's classified report (see also Chapters 3 and 4-in this report).

2.2.2 Ground Attacks Ground attacks on a nuclear facility could take three forms: (1) a direct assault on the facility by armed groups, (2) a stand-off attack using appropriate weapons, or (3) an assault having both air and ground components. The direct assault would likely be carried out by a group of well-armed and trained attackers, perhaps working with the assistance of an insider. The objective of such an attack would likely be to gain entry to protected and vital areas of the plant (FIGURE 2.1) to carry out radiological sabotage. The attackers would need to have knowledge of the design, location, and operation of the spent fuel facility to carry out such an attack successfully.

Commercial nuclear power plants are required by the Nuclear Regulatory Commission to maintain a professional guard force at each plant to defend against a Commission-developed design basis threat (DBT), which includes a ground assault. The protective force is a critical part of a nuclear power plant's security system for deterring, 1o All current dry cask storage facilities in the United States are constructed at ground level, whereas spent fuel pools can be located above or below grade, depending on plant design (see Chapter 3).

. 32 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE FIGURE 2.1 Commercial nuclear power plant sites are'demarcated as shown for security purposes. The part of the power plant site over which the plant operator exercises control is referred to as the owner-controlledarea.This usually corresponds to the boundary of the site. Located within this area are one or more protected areasto which access is restricted using guards, fences, and other barriers. Dry cask storage facilities, formally referred to as Independent Spent Fuel Storage Installations (ISFSIs), are located within these areas. The vital area of the plant contains the reactor core, support buildings, and the spent fuel pool. It is the most carefully controlled and guarded part of the plant site. SOURCE: Modified from Nuclear Regulatory Commission briefing materials (2004).

detecting, thwarting, or impeding attacks. The Commission staff declined to provide a formal briefing to the committee on the DBT for radiological sabotage, asserting that the committee did not have a need to know this information. Nevertheless, the committee was able to discern the details of the DBT from a series of presentations made by Nuclear Regulatory Commission staff. Commission staff also provided a fact check of this information as the classified report was being finalized.

Power plant operators are required to demonstrate to the Commission's satisfaction that there is "high assurance" that their guard forces can thwart the Commission-defined DBT assault. This guard force also must be able to provide deterrence against a beyond-DBT attack depending on the adversarial force. Reinforcing forces would be provided by local and state law enforcement aswell as federal forces. The Commission staff also informed the committee that since the September 11, 2001, attacks, the Commission has been working with DHS to improve coordination procedures with federal, state, and local agencies to improve their response capabilities in the event of an attack. DHS also is making grants to local law enforcement agencies around power plant sites to raise their capabilities to respond to requests for assistance.

TERRORIST A TTA CKS ON SPENT FUEL STORAGE 33 Since the September 11, 2001, attacks, the Nuclear Regulatory Commission has issued directives to power plant operators to enhance protection against vehicle bombs. The Commission also has issued directives to power plant operators to enhance protection against insider threats.

The committee does not have enough information to judge whether the measures at power plants are in fact sufficient to defend against either a DBT or a beyond-DBT attack on spent fuel storage. The Nuclear Regulatory Commission declined to provide detailed briefings to the committee on surveillance, security procedures, and security training at commercial nuclear.power plants. Consequently, the committee was unable to evaluate their effectiveness. A recent General Accounting Office report (GAO, 2003) was critical of some of these procedures, but the committee has no basis for judging whether these criticisms were justified. Nevertheless, the committee judges that surveillance and security procedures at commercial nuclear power plants are just as important as physical barriers in preventing successful terrorist attacks and mitigating their consequences.

2.2.3 Attacks Having Both Air and Ground Components Hybrid attacks that combine aspects of both air and ground attacks also could be mounted by terrorists. These could deliver attacking forces directly to a spent fuel 'storage facility, bypassing the security perimeters and security personnel deployed to protect against a ground attack. The committee considered various scenarios for such attacks. The committee judges that some scenarios are feasible. Details are provided in the classified report.

2.2.4 Terrorist Theft of Spent Fuel for Use in a Radiological Dispersal Device (RDD)

An RDD, or so-called dirty bomb, is a device that disperses radioactive material using chemical explosives or other means (NRC, 2002). RDDs do not involve fission-induced explosions of the kind associated with nuclear weapons. While RDD attacks can be carried out witFi any source of radioactivity, this discussion is confined to scenarios that involve the theft of spent fuel for such use.11 A crude RDD device could be fabricated simply by loading stolen spent fuel onto a truck carrying high explosives. The truck could be driven to another location and detonated. The dispersal of radioactivity from such an attack would be unlikely to cause many immediate deaths, but there could be fatalities from the chemical explosion as well as considerable cleanup costs and adverse psychological effects.

It would be difficult for terrorists to steal a large quantity of spent fuel (e.g., a single spent fuel assembly) for use in an RDD for three reasons. First, spent fuel is highly radioactive and therefore requires heavy shielding to handle. Second, the use of heavy equipment would be required to remove spent fuel assemblies from a pool or dry cask.

Third, controls are in place at plants to deter and detect such thefts. Additional details on these controls are provided in the classified report.

Theft and removal of an assembly or individual fuel rods during an assault on the plant might be easier, because the guard force would likely be preoccupied defending the plant. However, the amount of material that could be removed would be small, and getting it

'1 An attack on a spent fuel facility that resulted in the direct release of radioactivity would be an act of radiological sabotage of the kind considered previously in this chapter.

34 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE out of the plant would be time consuming and obvious to the plant defenders and other responding forces.

There are broken fuel rods and other debris, mostly from older assemblies, in storage at many plants. These materials are typically stored along the sides of the spent fuel pools and could be more easily removed from the plant than an entire assembly. Pieces of fuel rods also are sometimes intentionally removed from assemblies for offsite laboratory analysis. Some plants have misplaced fuel rod pieces.12 A knowledgeable insider might be able to retrieve some of this material from the pool, but getting it out of the plant under normal operating conditions would be difficult.

Even the successful theft of a part of a spent fuel rod would provide a terrorist with only a relatively small amount of radioactive material. Superior materials could be obtained from other facilities. This material also can be purchased (Zimmerman and Loeb, 2004).

Moreover, even with explosive dissemination, it is unlikely that much of the spent fuel will be aerosolized unless it is incorporated into a well-designed RDD. More likely, such an event would break up and scatter.the fuel pellets in relatively large chunks, which would not pose an overwhelming cleanup challenge.

Even though the likelihood of spent fuel theft appears to be small, it is nevertheless important that the protection of these materials be maintained and improved as vulnerabilities are identified.

2.3 RISKS OF TERRORIST ATTACKS ON SPENT FUEL STORAGE FACILITIES Nuclear Regulatory Commission staff told the committee that it believes that the consequences of a terrorist attack on a spent fuel pool would likely unfold slowly enough that there would be time to take mitigative actions to prevent a large release of radioactivity.

They also pointed out that since the September 11, 2001, attacks, the Nuclear Regulatory Commission has issued several orders that contain Interim Compensatory Measures that require power plant operators to consider potential mitigative actions in the event of such an attack. The committee received a briefing on some of these measures at one of its meetings. According to Commission staff, such measures provide an additional margin of safety.

The nuclear industry and the Nuclear Regulatory Commission have also asserted13 that the robust construction and stringent security requirements at nuclear power plants make them less vulnerable to terrorist attack than softer targets such as chemical plants and refineries (e.g., Chapin et al., 2002). They argue that scarce resources should be devoted to 12 For example, at the Millstone and Vermont Yankee plants in 2000 and 2003, respectively. Inthe case of Millstone, the Nuclear Regulatory Commission determined on the basis of extensive analysis that these rods were likely disposed of as low-level waste. After the committee's classified report was published, Commission staff informed the committee that Vermont Yankee had accounted for the missing rod segments and that Humbolt Bay had uncovered and is investigating an inventory discrepancy involving spent fuel rod segments.

13 These arguments tend to be generic in nature and do not differentiate spent fuel pools from the rest of the power plant.

TERRORISTATTACKS ON SPENT FUEL STORAGE 35 upgrading security at these other critical facilities rather than at already well-protected nuclear plants.

There are two unstated propositions in the argument that nuclear plants are less vulnerable than other facilities. The first speaks to the probability of terrorist attacks on such facilities; the second speaks to the consequences:

" Proposition 1: Nuclear power plants (and their spent fuel facilities) are less desirable as terrorist targets because they are robust and well protected.

" Proposition2. If attacked, nuclear plants (and their spent fuel storage facilities) are likely to sustain little or no damage because they are robust and well protected.

The committee obtained a briefing from the Department of Homeland Security to address the first proposition. Details are provided in the classified report.

While the committee's classified report was in review, the National Commission on Terrorist Attacks Upon the United States issued a staff paper (Staff Statement No. 16, Outline of the 9/11 Plot, pages 12-13) suggesting that al-Qaida initially included unidentified nuclear plants among an expanded list of targets for the September 11, 2001, attacks.

According to that report, these plants were eliminated from the target list along with several other facilities when the terrorist organization scaled back the number of planned attacks.

Nevertheless, if this information is correct, it provides further indications that commercial-nuclear power plants are of interest to terrorist groups,14 even though softer targets may have a higher priority with many terrorists.

With respect to the first proposition, the committee judges that it is not prudent to dismiss nuclear plants, including their spent fuel storage facilities, as undesirable targets for attacks by terrorists.

As to the second proposition that terrorist attacks are likely to cause little or no damage, a poorly designed attack or an attack by unsophisticated terrorists might produce little physical damage to the plant. There could, however, be severe adverse psychological effects from such an attack that could have considerable economic consequences. On the other hand, attacks by knowledgeable terrorists with access to advanced weapons might cause considerable physical damage to a spent fuel storage facility, especially in a suicide attack.

It is important to recognize that an attack that damages a power plant or its spent fuel facilities would not necessarily result in the release of any radioactivity to the environment. While it may not be possible to deter such an attack, there are many potential mitigation steps that can be taken to lower its potential consequences should an attack occur. These are discussed in some detail in the committee's classified report (see also Chapters 3 and 4 in this report).

14 In another example of concern, police in Toronto, Canada, detained 19 men in August 2003 based on suspicious activities that included surveillance and flying lessons that would take them over a nuclear power plant (Ferguson et al., 2004).

36 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE In summary, the committee judges that the plausibility of an attack on a spent fuel storage facility, coupled with the public fear associated with radioactivity, indicates that the possibility of attacks cannot be dismissed.

2.4 FINDINGS AND RECOMMENDATIONS With respect to the committee's task to "explicitly consider the risks of terrorist attacks on [spent fuel] and the risk these materials might be used to construct a radiological dispersal device," the committee offers the following findings and recommendations:

FINDING 2A: The probability of terrorist attacks on spent fuel storage cannot be assessed quantitatively or comparatively. Spent fuel storage facilities cannot be dismissed as targets for such attacks because it is not possible to predict the behavior and motivations of terrorists, and because of the attractiveness of spent fuel as a terrorist target given the well-known public dread of radiation.

Terrorists view nuclear power plant facilities as desirable targets because of the large inventories of radionuclides they contain. The committee believes that knowledgeable terrorists might choose to attack spent fuel pools because (1) at U.S. commercial power plants, these pools are less well protected structurally than reactor cores; and (2) they typically contain inventories of medium- and long-lived radionuclides that are several times greater than those contained in individual reactor cores.

FINDING 2B: The committee judges that the likelihood terrorists could steal enough spent fuel for use in a significant radiological dispersal device is small.

Spent fuel assemblies in pools or dry casks are large, heavy, and highly radioactive.

They are too large and radioactive to be handled by a single individual. Removal of an assembly from the pool or dry cask would prove extremely difficult under almost any terrorist attack scenario. Attempts by a knowledgeable insider(s) to remove single rods and related debris from the pool might prove easier, but it would likely be very difficult to get it out of the plant under normal operating conditions. Theft and removal during an assault on the plant might be easier because the guard force would likely be occupied defending the plant.

However, the amount of material that could be removed would be small. Moreover, there are other facilities from which highly radioactive material could be more easily stolen, and this material also can be purchased. Even though the likelihood of spent fuel theft appears to be small, it is nevertheless important that the protection of these materials be maintained and improved as vulnerabilities are identified.

RECOMMENDATION: The Nuclear Regulatory Commission should review and upgrade, where necessary, its security requirements for protecting spent fuel rods not contained in fuel assemblies from theft by knowledgeable insiders, especially in facilities where individual fuel rods or portions of rods are being stored in pools.

FINDING 2C: A number of security improvements at nuclear power plants have been instituted since the events of September 11, 2001. The Nuclear Regulatory Commission did not provide the committee with enough information to evaluate the effectiveness of these procedures for protecting stored spent fuel.

TERRORIST A TTA CKS ON SPENT FUEL STORAGE 37 Surveillance and security procedures are just as important as physical barriers in preventing and mitigating terrorist attacks. The Nuclear Regulatory Commission declined to provide the committee with detailed briefings on the surveillance and security procedures that are now in place to protect spent fuel facilities at commercial nuclear power plants against terrorist attacks. Although the committee did learn about some of the changes that have been instituted since the September 11, 2001, attacks, it was not provided with enough information to evaluate the effectiveness of procedures now in place.

RECOMMENDATION: Although the committee did not specifically investigate the effectiveness and adequacy of improved surveillance and security measures for protecting stored spent fuel, an assessment of current measures should be performed by an independent's organization.

15 That is, independent of the Nuclear Regulatory Commission and the nuclear industry.

3 SPENT FUEL POOL STORAGE This chapter addresses the first charge of the committee's statement of task to assess "potential safety and security risks of spent nuclear fuel presently stored in cooling pools at commercial reactor sites."1 As noted in Chapter 1, storage of spent fuel in pools at commercial reactor sites has three primary objectives:

• Cool the fuel to prevent heat-up to high temperatures from radioactive decay.

• Shield workers and the public from the radiation emitted by radioactive decay in the spent fuel and provide a barrier for any releases of radioactivity.

• Prevent criticality accidents.

The first two of these objectives could be compromised by a terrorist attack that partially or completely drains the spent fuel pool. 2 The committee will refer to such scenarios as "loss-of-pool-coolant" events. Such events could have several deleterious consequences:

Most immediately, ionizing radiation levels in the spent fuel building rise as the water level in the pool falls. Once the water level drops to within a few feet (a meter or so) of the tops of the fuel racks, elevated radiation fields could prevent direct access to the immediate areas around the lip of the spent fuel pool building by workers. This might hamper but would not necessarily prevent the application of mitigative measures, such as deployment of fire hoses to replenish the water in the pool.

The ability to remove decay heat from the spent fuel also would be reduced as the water level drops, especially when it drops below the tops of the fuel assemblies. This would cause temperatures in the fuel assemblies to rise, accelerating the oxidation of the zirconium alloy (zircaloy) cladding that encases the uranium oxide pellets. This oxidation reaction can occur in the presence of both air and steam and is strongly exothermic-that is, the reaction releases large quantities of heat, which can further raise cladding temperatures.

The steam reaction also generates large quantities of hydrogen:

Reaction in air: Zr + 02 -) ZrO 2 heat released = 1.2 x 107 joules/kilogram Reaction in steam: Zr + 2H2 0 -4 ZrO2 + 2H2 heat released = 5.8 x 106 joules/kilogram A basic description of pool storage can be found in Chapter 1 and historical background can be found in Appendix D.Section 3.1 provides additional technical details about pool storage.

2 The committee could probably design configurations in which fuel might be deformed or relocated to enable its re-criticality, but the committee judges such an event to be unlikely. Also, the committee notes that while re-criticality would certainly be an undesirable outcome, criticality accidents have happened several times at locations around the world and have not been catastrophic offsite. An accompanying breach of the fuel cladding would still be the chief concern.

38

SPENT FUEL POOL STORAGE3 39 These oxidation reactions can become locally self-sustaining (i.e., autocatalytic 3) at high temperatures (i.e., about a factor of 10 higher than the boiling point of water) if a supply of oxygen and/or steam is available to sustain the reactions. (These reactions will not occur when the spent fuel is under water because heat removal prevents such high temperatures from being reached).The result could be a runaway oxidation reaction-referred to in this report as.a zirconium cladding fire-that proceeds as a burn front (e.g., as seen in a forest fire or a fireworks sparkler) along the axis of the fuel rod toward the source of oxidant (i.e.,

air or steam). The heat released from such fires can be even greater than the decay heat produced in newly discharged spent fuel.

As fuel rod temperatures increase, the gas pressure inside the fuel rod increases and eventually can cause the cladding to balloon out and rupture. At higher temperatures (around 1800"C [approximately 3300"F]), zirconium cladding reacts with the uranium oxide

.fuel to form a complex molten phase containing zirconium-uranium oxide. Beginning with the cladding rupture these events would result in the release of radioactive fission gases and some of the fuel'ý radioactive material in the form of aerosols into the building that houses the spent fuel pool and possibly into the environment. If the heat from one burning assembly is not dissipated, the fire could spread to other spent fuel assemblies in the pool, producing a propagating zirconium cladding fire.

The high-temperature reaction of zirconium and steam has been described quantitatively since at least the early 1960s (e.g., Baker and Just, 1962). The accident at the Three Mile Island Unit 2 reactor and a set of experiments (e.g., CORA, FPT 1-6, CODEX, ORNL-VI, VERCORS) have provided a basis for understanding the phenomena of zirconium cladding fires and fission-product releases from irradiated fuel in a reactor core accident.

This understanding and data from the experiments form the foundation for computer simulations of severe accidents involving nuclear fuel. These experiments and computer simulations are for inside-reactor vessel events rather than events in an open-air spent fuel pool array.

This chlapter examines possible initiating factors for such loss-of-pool-coolant events and the potential consequences of such events. It is organized into the following four main sections:

• Background on spent fuel pool storage.

• Previous studies on safety and security of pool storage.

• Evaluation of the potential risks of pool storage.

• Findings and recommendations.

3That is, the reaction heat will increase temperatures in adjacent areas of the fuel rod, which in turn will accelerate oxidation and release even more heat. Autocatalytic oxidation leading to a "runaway" reaction requires a complex balance of heat and mass transfer, so assigning a specific ignition temperature is not possible. Empirical equations have been developed to predict the reaction rate as a function of temperature when steam and oxygen supply are not limited (see, e.g., Tong and Weisman, 1996, p. 223). Numerous scaled experiments have found that the oxidation reaction proceeds very slowly below approximately 900°C (1700"F).

40 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE

3.1 BACKGROUND

ON SPENT FUEL POOL STORAGE After a power reactor is shut down, its nuclear fuel continues to produce heat from radioactive decay (see FIGURE 1.2). Although only one-third of the fuel in the reactor core is replaced during each refueling cycle, operators commonly offload the entire core (especially at pressurized water reactors [PWRs]) into the pool during refueling 4 to facilitate loading of fresh fuel or for inspection or repair of the reactor vessel and internals. Heat generation in the pool is at its highest point just after the full core has been offloaded.

Pool heat loads can be quite high, as exemplified by a "typical" boiling water reactor (BWR) which was used in some of the analyses discussed elsewhere in this chapter (this BWR is hereafter referred to as the "reference BWR"). This pool has approximately 3800 locations for storage of spent fuel assemblies, about 3000 of which are occupied by four-and-one-third reactor cores (13 one-third-core offloads) in a pool approximately 35 feet wide, 40 feet long, and 39 feet deep (10.7 meters wide, 12.2 meters long, and 11.9 meters deep) with a water capacity of almost 400,000 gallons (1.51 million liters). According to Nuclear Regulatory Commission staff, the total decay heat in the spent fuel pool is 3.9 megawatts (MW) ten days after a one-third-core offload. The vast majority of this heat is from decay in the newly discharged spent fuel. Heat loads would be substantially higher in spent fuel pools that contained a full-core offload.

Although spent fuel pools have a variety of designs, they share one common characteristic: Almost all spent fuel pools are located outside of the containment structure that holds the reactor pressure vessel., In some reactor designs, the spent fuel pools are contained within the reactor building,6 which is typically constructed of about 2 feet of reinforced concrete (see FIGURE 3.1). In other designs, however, one or more walls of the spent fuel pool may be located on the exterior wall of an auxiliary building that is located adjacent to the containment building (see FIGURE 3.2). As described in more detail below, some pools are built at or below grade, whereas others are located at the top of the reactor building.

The enclosing superstructures above the pool are typically steel, industrial-type buildings designed to house cranes that are used to move reactor components, spent fuel, and spent fuel casks. These superstructures above the pool are designed to resist damage from seismic loads but not from large tomado-bome missiles (e.g., cars and telephone

.poles), which would usually impact the superstructures at low angles (i.e., moving horizontally). In contrast, the typical spent fuel pool is robust. The pool walls and the external walls of the building housing the pool (these external walls may incorporate one or more pool walls in some plants) are designed for seismic stability and to resist horizontal

-A 1996 survey by the Nuclear Regulatory Commission (USNRC, 1996) found that the majority of commercial power reactors routinely offload their entire core to the spent fuel pool during refueling outages. The practice is more common among PWRs than BWRs, which tend to offload only that fuel that is to be replaced, but some BWRs do offload the full core. In response to a committee inquiry, an Energy Resources International staff member confirmed that this is still the case today.

5The exceptions in the United States are the Mark III BWRs, which have two pools, one of which is inside the containment. As discussed in Appendix C, spent fuel pools at German commercial nuclear rower plants also are located inside reactor containment structures.

A PWR containment structure is a large, domed building that houses the reactor pressure vessel, the steam generators, and other equipment. Ina BWR, the containment structure houses less equipment, is located closer in to the pressure vessel, and sits inside a building called the reactor building, which also houses the spent fuel pool and safety-related equipment to support the reactor.

SPENT FUEL POOL STORAGE 41 wprs.o Toraus chambet FIGURE 3.1 Schematic section through a G.E. Mark I BWR reactor plant. The spent fuel pool is located in the reactor building well above ground level. This diagram is for a BWR with a reinforced concrete superstructure (roof). Most designs have thin steel superstructures. SOURCE: Lamarsh (1975, Figure 11.3).

strikes of tornado missiles. The superstructures and pools were not, however, specifically designed to resist terrorist attacks.

The typical spent fuel pool is about 40 feet (12 meters) deep and can be 40 or more feet (12 meters) in each horizontal dimension. The pool walls are constructed of reinforced concrete typically having a thickness between 4 and 8 feet (1.2 to 2.4 meters). The pools.

contain a '- to 'A-inch-thick (6 to 13 mm) stainless steel liner, which is attached to the walls with studs embedded in the concrete. The pools also contain vertical storage racks for holding spent and fresh fuel assemblies, and some pools have a gated compartment to hold a spent fuel storage cask while it is being loaded and sealed (see Chapter 4).

The storage racks areabout 13 feet (4 meters) in height and are installed near the bottom of the spent fuel pool. The racks have feet to provide space between their bottoms and the pool floor. There is also space between the sides of the rack and the steel pool liners for circulation of water (FIGURE 3.3). There are about 26 feet (8 meters) of water above the top of thespent fuel racks. This provides substantial radiation shielding even when an assembly is being moved above the rack. Transfers of spent fuel from the reactor core to the spent fuel pool or from the pool to storage casks are carried out underwater to provide shielding and cooling.

The general elevation of the spent fuel pool matches that of the vessel containing the reactor core. Pressurized water reactor designs use comparatively shorter reacto&

42 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE FIGURE 3.2 Schematic section through a PWR reactor plant. The spent fuel pool is located in the fuel-handling building next to the domed reactor containment building at or slightly below ground level. SOURCE: Modified from Duderstadt and Hamilton (1976, Figure 3-4).

vessels closer to ground level (grade) and also have spent fuel pools that are close to grade (FIGURE 3.2). The design shown in this figure is typical of the fuel pool arrangement for PWRs. Nuclear power plant sites that contain two reactors are usually arranged in a mirror-image fashion, with the two spent fuel pools (or a shared pool) located in a common area adjoining both reactor buildings. For single-plant or two-plant arrangements, the building covering the spent fuel pool and crane structures is typically an ordinary steel industrial building. There are 69 PWRs currently in operation in the United States; 6 PWRs have been decommissioned but continue to have active spent fuel pool storage.

In contrast, in boiling water reactor designs, the reactor vessel is at a higher elevation, and the BWR vessels are somewhat taller than PWR vessels. 7 Consequently, BWRs have more elevated spent fuel pools, generally well above grade. FIGURE 3.1 shows the general design for the 22 BWR Mark I plants operating in the United States.

Nuclear Regulatory Commission staff is conducting a survey of the plants to obtain a better understanding of the variations in design of spent fuel pools across the nation. The following information was provided to the committee from that survey:

7The higher elevation accommodates control mechanisms that sit under the reactor, and the extra height accommodates steam separation and drying equipment at the top of the vessel. The fuel is about the same length as PWR fuel.

SPENT FUEL POOL STORAGE4 43 FIGURE 3.3 Example of a section of a PWR spent fuel pool and support facilities. The pool is located to the right in the figure; the support equipment to the left. SOURCE: American Nuclear Society (1988).

PWR spent fuel pools: Spent fuel pools are located in buildings adjoining the reactor containment. buildings at PWR plants (see FIGURE 3.2). Some pools are posif[oned such that their spent fuel is below grade. As shown in Figure 3.2, some pool walls also serve as the external walls of the spent fuel pool buildings.

Some plants have structures surrounding the spent fuel pool building that would provide some shielding of the pools from low-angle line-of-sight attacks. A more complete plant survey would be needed to establish the extent of pool exposure-to such attacks.

• BWR spent fuel pools: MARK I and IIBWR plants are located above grade and are shielded by at least one exterior building wall. Some pools are also shielded by the reactor buildings. Some pools are also shielded by "significant" surrounding structures, and some have supplemental floor, and column supports.

The vulnerability of a spent fuel pool to terrorist attack depends in part on its location with respect to ground level as well as its construction. Pools are potentially susceptible to attacks from above or from the sides depending on their elevation with respect to grade and the presence of surrounding shielding structures.

As noted in Chapter 1, nearly all pools contain high-density spent fuel racks. These racks allow approximately five times as many assemblies to be stored in the pool as would have been possible with the original racks, which had open lateral channels between the fuel assemblies to enhance water circulation.

44 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 3.2 PREVIOUS STUDIES ON SAFETY AND SECURITY OF POOL STORAGE Several reports have been published on the safety of spent fuel pool storage. One of the earliest analyses was contained in the ReactorSafety Study (U.S. Atomic Energy Commission, 1975), which concluded that spent fuel pool safety risks were very much smaller than those involving the cores of nuclear reactors. This conclusion is not surprising:

The cooling system in a spent fuel pool is simple. The coolant is at atmospheric pressure; the spent fuel is in a subcritical configuration and generates little heat relative to that generated in an operating reactor, and the design and location of piping in the pool make a severe loss-of-pool-coolant event unlikely during normal operating conditions. Despite changes in reactor and fuel storage operations, such as longer fuel residence times in the core and higher-density pool storage, the conclusions of that study are still broadly applicable today. It is important to recognize, however, that the Reactor Safety Study did not address the consequences of terrorist attacks.

The Nuclear Regulatory Commission and its contractors have periodically re-analyzed the safety of spent nuclear fuel storage (see Benjamin et al., 1979; BNL, 1987, 1997; USNRC, 1983, 2001a, 2003b). All of these studies suggest that a loss-of-pool-coolant event could trigger a zirconium cladding fire in the exposed spent fuel. The Nuclear Regulatory Commission considered such an accident to be so unlikely that no specific action was warranted, despite changes in reactor operations that have resulted in increased fuel bum-ups and fuel storage operations that have resulted in more densely packed spent fuel pools.

In 2001, the Nuclear Regulatory Commission published NUREG-1738, Technical Study of Spent Fuel PoolAccident Risk at DecommissioningNuclearPower Plants, to provide a technical basis for rulemaking for power plant decommissioning (USNRC, 2001a).

A draft of the study was issued for public comments, including comments by the Advisory Committee on Reactor Safeguards and a quality review of the methods, assumptions, and models used in the analysis was carried out by the Idaho National Engineering and Environmental Laboratory.

The study provided a probabilistic risk assessment that identified severe accident scenarios and estimated their consequences. The analysis determined, for a given set of fuel characteristics, how much time would be required to boil off enough water to allow the fuel rods to reach temperatures sufficient to initiate a zirconium cladding fire.

The analysis suggested that large earthquakes and drops of fuel casks from an overhead crane during transfer operations were the two event initiators that could lead to a loss-of-pool-coolant accident. For cases where active cooling (but not the coolant) has been lost, the thermal-hydraulic analyses suggested that operators would have about 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> (more than four days) to act before the fuel was uncovered sufficiently through boiling of cooling water in the pool to allow the fuel rods to ignite. This time was characterized as an "underestimate" given the simplifications assumed for the loss-of-pool-coolant scenario.

The overall conclusion of the study was that the risk of a spent fuel pool accident leading to a zirconium cladding fire was low despite the large consequences because the predicted frequency of such accidents was very low. The study also concluded, however, that the consequences of a zirconium cladding fire in a spent fuel pool could be serious and, that once the fuel was uncovered, it might take only a few hours for the most recently discharged spent fuel rods to ignite.

SPENT FUEL POOL STORAGE 45 A paper by Alvarez et al. (2003a; see also Thompson, 2003) took the analyses in NUREG-1738 to their logical ends in light of the September 11, 2001, terrorist attacks:

Namely, what would happen if there were a loss-of-pool-coolant event that drained the spent fuel pool? Such an event was not considered in NUREG-1 738, but the analytical results in that study were presented in a manner that made such an analysis possible.

Alvarez and his co-authors concluded that such an event would lead to the rapid heat-up of spent fuel in a dense-packed pool to temperatures at which the zirconium alloy cladding would catch fire and release many of the fuel's fission products, particularly cesium-1 37. They suggested that the fire could spread to the older spent fuel, resulting in long-term contamination consequences that were worse than those from the Chemobyl accident. Citing two reports by Brookhaven National Laboratory (BNL, 1987, 1997), they estimated that between 10 and 100 percent of the cesium-1 37 could be mobilized in the plume from the burning spent fuel pool, which could cause tens of thousands of excess cancer deaths, lot*s of tens of thousands of square kilometers of land, and economic losses in the hundreds of billions of dollars. The excess cancer estimates were revised downward to between 2000 and 6000 cancer deaths in a subsequent paper (Beyea et al., 2004) that more accurately accounted for average population densities around U.S. power plants.

Alvarez and his co-authors recommended that spent fuel be transferred to dry storage within five years of discharge from the reactor. They noted that this would reduce the radioactive inventories in spent fuel pools and allow the remaining fuel to be returned to open-rack storage to allow for more effective coolant circulation, should a loss-of-pool-coolant event occur. The authors also discussed other compensatory measures that could be taken to reduce the consequences of such events.

The Alvarez et al. (2003a) paper received extensive attention and comments, including a comment from the Nuclear Regulatory Commission staff (USNRC, 2003a; see Alvarez et al., 2003b, for a response). None of the commentators challenged the main conclusion of the Alvarez et al. (2003a) paper that a severe loss-of-pool-coolant accident might lead to a-spent fuel fire in a dense-packed pool. Rather, the commentators challenged the likelihood that such an event could occur through accident or sabotage, the assumptions used to calculate the offsite consequences of such an event, and the cost-effectiveness of the authors' proposal to move spent fuel into dry cask storage. One commentator summarized these differences in a single sentence (Benjamin, 2003, p. 53): "In a nutshell,

[Alvarez et al.] correctly identify a problem that needs to be addressed, but they do not adequately demonstrate that the proposed solution is cost-effective or that it is optimal."

The Nuclear Regulatory Commission staff provided a briefing to the committee that provides a further critique of the Alvarez et al. (2003a) analysis that goes beyond the USNRC (2003a) paper. Commission staff told the committee that the NUREG-1738 analyses attempted to provide a bounding analysis of current and conceivable future spent fuel pools at plants undergoing decommissioning and therefore relied on conservative assumptions. The analysis assumed, for example, that the pool contained an equivalent of three-and-one-half reactor cores of spent fuel, including the core from the most recent reactor cycle. The staff also asserted that NUREG-1738 did not provide a realistic analysis of consequences. Commission staff concluded that "the risks and potential societal cost of

[a] terrorist attack on spent fuel pools do not justify the complex and costly measures

46 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE proposed in Alvarez et al. (2003) to move and store 1/3 of spent fuel pools [sic] inventory in dry storage casks."8 The committee provides a discussion of the Alvarez et al. (2003a) analysis in its classified report. The committee judges that some of their release estimates should not be dismissed.

The 2003 Nuclear Regulatory Commission (USNRC, 2003b) staff publication NUREG-0933, A Prioritizationof Generic Safety Issues,9 discusses beyond-design-basis accidents in spent fuel pools. The study draws some of the same consequence conclusions as the Alvarez et al. (2003a) paper. It notes that in a dense-packed pool, a zirconium cladding fire "would probably spread to most or all of the spent fuel pool" (p. 1). This could drive what the report refers to as "borderline aged fuel" into a molten condition leading to the release of fission products comparable to molten fuel in a reactor core.

The NUREG-0933 report (USNRC, 2003b) summarizes technical analyses of the frequencies of severe accidents for three BWR scenarios. The report concludes that the greatest risk is from a beyond-design-basis seismic event. While the consequences of such accidents are considerable, the report concludes that their frequencies are no greater than would be expected for reactor core damage accidents due to seismic events beyond the design basis safe shutdown earthquake.

An analysis of spent fuel. operating experience by the Nuclear Regulatory Commission staff (USNRC, 1997) showed that several accidental partial-loss-of-pool-coolant events have occurred as a result of human error. Two of these involved the loss of more than 5 feet of water from the pool, but none had serious consequences. Nevertheless, Commission staff suggested that plant-specific analyses and corrective actions should be taken to reduce the potential for such events in the future.

It is important to recognize that with the exception of the Alvarez et al. (2003a) paper, all of the previous U.S. work reviewed by the committee has focused on safety risks, not security risks. The Nuclear Regulatory Commission analyses of spent fuel storage vulnerabilities were not completed by the time the committee finalized its information gathering for this report, but the committee did receive briefings on this work. In addition, analyses have been undertaken of external impacts on power plant structures by aircraft for the few commercial power plants that are located close enough to airports to consider hardening of the plant design to resist accidental aircraft crashes. These analyses were done as part of the plants' licensing safety analyses. The committee did not look further into these few plants because the aircraft considered were smaller and the impact velocities considered were much lower than those that might be brought to bear in a well-planned terrorist attack.

The committee did learn about work to assess the risks of spent fuel storage to terrorist attacks in Germany (see Appendix C for a description). However, the details of this work are classified by the German government and therefore are unavailable to the 8The quote is from a PowerPoint presentation made by Nuclear Regulatory Commission staff to the committee at one of its meetings.

9 NUREG-0933 is a historical record that provides a yearly update of generic safety issues. It does not provide any additional technical analysis of these issues.

SPENT FUEL POOL STORAGE 47 committee for review. Consequently, the committee was unable to provide a technical assessment.

3.3 EVALUATION OF THE POTENTIAL RISKS OF POOL STORAGE Prior to the September 11, 2001, terrorist attacks, spent fuel pool analyses by the Nuclear Regulatory Commission were focused almost exclusively on safety. On the basis of these analyses, the Commission concluded that spent fuel storage carried risks that were no greater (and likely much lower) than risks for operating nuclear reactors, as discussed in the previous section of this chapter.

The September 11, 2001, terrorist attacks raised the possibility of a new kind of threat to commercial power plants and spent fuel storage: premeditated, carefully planned, high-impact attacks by terrorists to damage these facilities for the purpose of releasing radiation to the environment and spreading fear and panic among civilian populations. The Commission informed the committee that its conclusions about risks of spent fuel storage are now being reevaluated in light of these new threats.

Prior to September 11, the Nuclear Regulatory Commission viewed the most credible sabotage event as a violent extemal land assault by small groups of well-trained, heavily armed individuals aided by a knowledgeable insider.10 The Commission has long-established requirements for physical protection systems at power plants to thwart such assaults. The committee was told that these requirements have been increased since the September 11,2001, attacks. To the committee's knowledge, there are currently no requirements in place to defend against the kinds of larger-scale, premeditated, skillful attacks that were carried out on September 11, 2001, whether or not a commercial aircraft is involved. Staff from the Nuclear Regulatory Commission and representatives from the nuclear industry repeatedly told the committee that they view detecting, preventing, and thwarting such attacks as the federal government's responsibility.

It is important to recognize that nuclear power plants in the United States and most of the rest of the world" were designed primarily with safety, not security, in mind.12 The reinforced concrete containment buildings that house the reactors were designed to contain internal pressures of up to about 4 atmospheres in case steam is released in the event of..

various hypothetical reactor accidents. These and other plant structures were not specifically designed to resist external terrorist attacks, although their robust construction would certainly provide significant protection against external assaults with airplanes or other types of weapons. Moreover, commercial power plants are substantially more robust than other critical infrastructure such as chemical plants, refineries, and fossil-fuel-fired electrical generating stations.

10 This is known as the "design basis threat" for radiological sabotage of nuclear power plants. See Chapter 2.

11 Spent fuel storage facilities in Germany are designed to survive the impact of a Phantom military jet without a significant release of radiation. Since September 11, 2001, the Germans have also examined the impact of a range of aircraft, including large civilian airliners, on these facilities. A discussion is provided in Appendix C.

12 No nuclear power plant ordered after the mid-1 970s has been built in the United States, so the designs were developed long before domestic terrorism of the kind seen on September 11, 2001, became a concern.

48 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE In the wake of the. September 11, 2001, attacks, a great deal of additional work hias been or is being carried out by government and private entities to assess the security risks posed by terrorist attacks against nuclear power plants and spent fuel storage. The committee provides a discussion of these studies in the following subsections. Some of these studies are still in progress.

The committee's discussion of this work in the following subsections is organized around the following two questions:

(1) Could an accident or terrorist attack lead to a loss-of-pool-coolant event that would partially or completely drain a spent fuel pool?

(2) What would be the radioactive releases if a pool were drained?

3.3.1 Could a Terrorist Attack Lead to a Loss-of-Pool-Coolant Event?

A terrorist attack that either disrupted the cooling system for the spent fuel pool or damaged or collapsed the pool itself could potentially lead to a loss-of-pool-coolant event.

The cooling system could be disrupted by disabling or damaging the system that circulates water from the pool to heat exchangers to remove decay heat. This system would not likely be a primary target of a terrorist attack, but it could be damaged as the result of an attack on the spent fuel pool or other targets at the plant (e.g., the power for the pumps could be interrupted). The loss of cooling capacity would be of much greater concern were it to occur during or shortly after a reactor offloading operation, because the pool would contain a large amount of high decay-heat fuel.

The consequences of a damaged cooling system would be quite predictable: The temperature of the pool water would rise until the pool began to boil. Steam produced by boiling would carry away heat, and the steam would cool as it expanded into the open space above the pool.13 Boiling would slowly consume the water in the pool, and if no additional water were added the pool level would drop. It would likely take several days of continuous boiling to uncover the fuel. Unless physical access to the pool were completely restricted (e.g., by high radiation fields or debris), there would likely be sufficient time to bring in auxiliary water supplies to keep the water level in the pool at safe levels until the cooling system could be repaired. This conclusion presumes, of course, that technical means, trained workers, and a sufficient water supply were available to implement such measures.

The Nuclear Regulatory Commission requires that alternative sources of water be identified and available as an element of each plant's operating license.

The pool-boiling event described above could result in the release of small amounts of radionuclides that are normally present in pool water.14 These radionuclides would likely have little or no offsite impacts given their small concentrations in the steam and their subsequent dilution in air once released to the environment. Moreover, as long as the spent fuel is covered with a steam-water mixture, it would not heat up sufficiently for the cladding to ignite.

A loss-of-pool-coolant event resulting from damage or collapse of the pool could 13 The building above the spent fuel pool contains blow-out panels that could be removed to provide additional ventilation.

14 This contamination may enter the water from damaged fuel or from neutron-activated materials that build up on the external surfbces of the fuel assemblies. The latter material is referred to as "crud."

SPENT FUEL POOL STORAGE 49 have more severe consequences. Severe damage of the pool wall could potentially result from several types of terrorist attacks, for instance:

(1) Attacks with large civilian aircraft.

(2) Attacks with high-energy weapons.

(3) Attacks with explosive charges.

The committee reviewed two independent analyses of aircraft impacts on power plant structures: A study sponsored by EPRI completed in 2002 provides a generic analysis of civilian airliner impacts on commercial power plant structures (EPRI, 2002). A study in progress by Sandia National Laboratories for the Nuclear Regulatory Commission examines the consequences of an aircraft impact on an actual BWR power plant.

The EPRJ and Sandia analyses used different finite element and finite difference codes that are in6common use in research and industry.15 Both sets of analyses attempted to validate the codes against physical tests, such as the Sandia "slug tests" that impacted water barrels into a concrete test wall at high speeds. EPRI's analysis used a Riera impact loading condition, which models the aircraft impact on a rigid structure and is a slightly conservative assumption because the structures are in fact deformable. The Sandia.

analysis was carried out on powerful computers that allowed the aircraft to be included explicitly in the calculations.

The committee also reviewed the preliminary results of Nuclear Regulatory Commission studies on the response of thick reinforced concrete walls such as those used in spent fuel pools to attacks involving simple explosive charges and other high-energy devices. The details of the analyses were not provided and therefore could not be evaluated quantitatively. However, some of these preliminary results are described in the committee's classified report.

The results of these aircraft and assault studies are classified or safeguards information. The committee has concluded that there are some scenarios that could lead to the partial failure of the spent fuel pool wall, thereby resulting in the partial or complete loss of pool coolant. A zirconium cladding fire could result if timely mitigative actions to cool the fuel were not taken. Details are provided in the classified report.

3.3.2 What would be the Radioactive Releases if a Pool Were Drained?

There are two ways in which an attack on a spent fuel pool could spread radioactive contamination: mechanical dispersion and zirconium cladding fires. An explosion or high-energy impact directly on the spent fuel could mechanically pulverize and loft fuel out of the pool. This would contaminate the plant and surrounding site with pieces of spent fuel. Large-15The EPRI analyses used several finite element models (ABAQUS, LS DYNA, ANACAP, and WINFRITH) and Riera impact functions. The Sandia analyses used the CTH finite difference model and the Pronto3D finite element analysis model. The CTH code has been used for a wide range of impact penetration and explosive detonation problems by the Department of Energy, the Department of Defense, and industry during the past decade. CTH results have been compared extensively with experimental results. As an Eulerian code (where material flows through a fixed grid) it can readily handle severe distortions. It also has a variety of computational material models for dynamic (high-strain-rate) conditions, although it is limited in that itdoes not explicitly model structural members, such as rebar and metal liners in the concrete structure, because of computational requirements.

50 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE scale offsite releases of the radioactive constituents would not occur, however, unless they were mobilized by a zirconium cladding fire that melted the fuel pellets and released some of their radionuclide inventory. Such fires would create thermal plumes that could potentially transport radioactive aerosols hundreds of miles downwind under appropriate atmospheric conditions.

The Nuclear Regulatory Commission is now sponsoring work at Sandia National Laboratories to improve upon the analyses in NUREG-1738 (USNRC, 2001a), and in particular to obtain an improved phenomenological understanding of the thermal and hydraulic processes that would occur in a spent fuel pool from a loss-of-pool-coolant event.

The committee received briefings on this work from Commission and Sandia staff during the course of this study. Additionally, the committee received a briefing from ENTERGY Corp.

staff and its consultants under contract to analyze and understand the consequences of a loss-of-pool-coolant event in a spent fuel pool in a PWR plant.

The Sandia analyses were carried out on the reference BWR described in Section 3.1. Sandia's analysis of a PWR spent fuel pool had only just begun by the end of May 2004 and has not yet yielded any results. The committee had less opportunity to examine ENTERGY's approach and results. Because of these limitations, the committee was unable to examine in any detail the effects of the differences between BWR and PWR pools and fuel, except as noted with respect to their locations relative to grade.

The analyses were carried out using several well-established computer codes. The MELCOR code, which was developed by Sandia for use in analyzing severe-reactor core accidents, was used to model fluid flow, heat transfer, fuel cladding oxidation kinetics, and fission product release phenomena associated with spent fuel assemblies. This code has been benchmarked against data from experiments (e.g., the FPT experiments on the Ph~bus test facility, and the VERCORS, CORA, and ORNL VI experiments)16 that involve zirconium oxidation kinetics and fission product release. However, none of the experiments was designed to simulate the physical conditions in a spent fuel pool. Many of the phenomena are not significantly different in a reactor core and in a spent fuel pool, but a few important differences, particularly concerning fire propagation from hotter fuel assemblies to cooler fuel assemblies and nuclear fuel volatilities, warrant more detailed analyses or further experiments. In principle, MELCOR can perform "best-estimate" calculations that address a range of accident evolutions, accounting for temperature, availability of oxidizing air and steam,17 and speciation and transport of radionuclides.

Sandia calculated the decay heat in the assemblies using the ANSI/ANS 5.1 code based on actual characteristics of the spent fuel (i.e., actual fuel ages, bum-ups, and locations) in the reference BWR pool. Flow and mixing behavior in the pool and reactor building enclosing the pool were modeled using a separate computational fluid dynamics (CFD) code.

Two types of analyses were carried out. A "separate effects" analysis was undertaken to examine the thermal responses of a spent fuel assembly (FIGURE 3.4) in a 16 These experiments were designed to examine phenomena that occur in reactor cores during severe accidents. The phenomena include core degradation.

17 Oxygen feeds the zirconium reaction and enhances release and transport of ruthenium-1 06, and the steam reaction releases hydrogen; whereas limited availability of oxygen starves the reaction.

Steam can also entrain released fission products.

SPENT FUEL POOL STORAGE 51 9 x 9 BWR Assemblies 2 Water Rods A 74 Fuel Rods 5 Assemblies

).2 I

Bypass Regions B

Concrete FIGURE 3.4 Configuration of fuel assemblies used for separate effects analysis. (A) Top view of BWR spent fuel assemblies used in the model. (B) Side view showing spent fuel assemblies in the pool. SOURCE: Nuclear Regulatory Commission briefing materials (2004).

52 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE A

B FIGURE 3.5 Two configurations used in the separate effects models shown in FIGURE 3.4:

(A) Center hot spent fuel assembly surrounded by four cold assemblies; and (B) center hot spent fuel assembly surrounded by four hot assemblies. SOURCE: Nuclear Regulatory Commission briefing materials (2004).

loss-of-pool-coolant event. This analysis was used to understand how thermal behavior is influenced by factors such as decay heat in the fuel assembly, heat transfer with adjacent assemblies, and heat transfer to circulating air or steam in a drained spent fuel pool. This analysis was used to guide the development of "global response" models to examine the thermal-hydraulic behavior of an entire spent fuel pool.

The separate effects analysis examined the thermal behavior of a high decay-heat BWR spent fuel assembly surrounded either by four low decay-heat assemblies (FIGURE 3.5A) or four high decay-heat assemblies (FIGURE 3.5B). This analysis showed that the potential for heat build-up in a fuel assembly sufficient to initiate a zirconium cladding fire depends on its decay heat (which is related to its age) and on the rate at which heat can be transferred to adjacent assemblies and to circulating air or steam.

SPENT FUEL POOL STORAGE5 53 In the configuration shown in FIGURE 3.5A, the low decay-heat assemblies act as thermal radiation heat sinks, thereby allowing the more rapid transfer of heat away from the center fuel assembly than would be the case if the center assembly were surrounded by high decay-heat assemblies. The results from this analysis indicate that this configuration can be air cooled sufficiently to prevent the initiation of a zirconium cladding fire within a relatively short time after the center fuel assembly is discharged from the reactor. In the configuration shown in FIGURE 3.5B, heat transfer away from the center assembly is reduced and heat build-up is more rapid. Results indicate that this configuration cannot be air cooled for a significantly longer time after the center fuel assembly is discharged from the reactor.

The global analysis modeled the actual design and fuel loading pattern of the reference BWR spent fuel pool. The pool was divided into seven regions based on fuel age.

.Within each of those seven regions, the model for the fuel racks was subdivided into 16 zones. The grou1i'Ing of assemblies into zones reduced the computational requirements compared to modeling every assembly.1 8 Two scenarios were examined: (1) a complete loss-of-pool-coolant scenario in which the pool is drained to a level below the bottom of spent fuel assemblies; and (2) a partial-loss-of-pool-coolant scenario in which water levels in the pool drain to a level somewhere between the top and bottom of the fuel assemblies. In the former case, a convective air circulation path can beestablished along the entire length of the fuel assemblies, which promotes convective air cooling of the fuel. In the latter case, an effective air circulation path cannot form because the bottom of the assembly is blocked by water. Steam is generated by boiling of the pool water, and the zirconium cladding oxidation reaction produces hydrogen gas. This analysis suggests that circulation blockage has a significant impact on thermal behavior of the fuel assemblies. The specific impact depends on the depth to which the pool is drained.

The global analysis examined the thermal behavior of fuel assemblies in the pool at 1, 3, and 12 months after the offloading of one-third of a core of spent fuel from the reactor.

Sensitivity studies were carried out to assess the importance of radiation heat transfer between different regions of the pool, the effects of building damage on releases of radioactive material to the environment, and the effects of varying the assumed location and size of the hole in the pool wall.

The results of these analyses are provided in the committee's classified report. For.

some scenarios, the fuel could be air cooled within a relatively short time after its removal from the reactor. If a loss-of-coolant event took place before the fuel could be air cooled, however, a zirconium cladding fire could be initiated if no mitigative actions were taken.

Such fires could release some of the fuel's radioactive material inventory to the environment in the form of aerosols.

For a partial-loss-of-pool-coolant event, the analysis indicates that the potential for zirconium cladding fires would exist for an even greater time (compared to the complete-loss-of-pool-coolant event) after the spent fuel was discharged from the reactor because air circulation can be blocked by water at the bottom of the pool. Thermal coupling between adjacent assemblies will be due primarily to radiative rather than convective heat transfer.

However, this heat transfer mode has been modeled simplistically in the MELCOR runs 18 The global-response model runs took between 10 and 12 days on the personal computers used in the Sandia analyses.

54 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE performed by Sandia. 19 If the water level is above the top of the fuel racks, decay heat in the fuel could cause the pool water to boil. Once water levels fall below a certain level in the fuel assembly, the exposed portion of the fuel cladding might heat up sufficiently to ignite if no mitigative actions were taken. This could result in the release of a substantial fraction of the cesium inventory to the environment in the form of aerosols.

A zirconium cladding fire in the presence of steam could generate hydrogen gas over the course of the event. The generation and transport of hydrogen gas in air was modeled in the Sandia calculations as was the deflagration of a hydrogen-air mixture in the closed building space above the spent fuel pool. The deflagration of hydrogen could enhance the release of radioactive material in some scenarios.

Sandia was just beginning to carry out a similar set of analyses for a "reference" PWR spent fuel pool when the committee completed information gathering for its classified report. There are reasons to believe that the results for a PWR pool could be somewhat different, and possibly more severe, than for a BWR pool: PWR assemblies are larger, have somewhat higher burn-ups, and some assemblies sit directly over the rack feet, which may impede cooling. While PWR fuel assemblies hold more fuel, they also have more open channels within them for water circulation. The committee was told that as part of this work, a sensitivity analysis will be carried out to understand how design differences among U.S.

PWRs will influence the model results.

ENTERGY Corp. has carried out independent separate-effects modeling of a PWR spent fuel pool using the MELCOR code. The analyses addressed both partial and complete loss-of-pool-coolant events for its PWR spent fuel assemblies in a region of the pool where there are no water channels in the spent fuel racks. The analyses were made for relatively fresh spent fuel assemblies (i.e., separate models were run for assemblies that had been discharged from the reactor for 4, 30, and 90 days) surrounded by four "cold" assemblies that had been discharged for two years. In general, the ENTERGY results are similar to those from the Sandia separate-effects analyses mentioned above..

Several steps could be taken to mitigate the effects of such loss-of-pool-coolant events short of removal of spent fuel from the pool. Among these are the following:

The spent fuel assemblies in the pools can be reconfigured in a "checkerboard" pattern so that newer, higher decay-heat fuel elements are surrounded by older, lower decay-heat elements. The older elements will act as radiation heat sinks in the event of a coolant loss so that the fuel is air coolable within a short time of its discharge from the reactor. Alternatively, newly discharged fuel can be placed I

near the pool wall, which also acts as a heat sink. ENTERGY staff estimates that reconfiguring the fuel in one of its pools into a checkerboard pattern would take only about 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of extra work, but would not extend a refueling outage.

Reconfiguring of fuel already in the pool could be done at any time. It does not require a reactor outage.

19 In a reactor core accident, heat transfer by thermal radiation is not important because all of the fuel assemblies are at approximately the same temperature. Consequently, there is no net heat transfer between them. But spent fuel pools contain assemblies of different ages, burn-ups, and decay-heat production. The hotter assemblies will radiate heat to cooler assemblies.

SPENT FUEL POOL STORAGE 55

• If there is sufficient space in the pool, empty slots can also be arranged to promote natural air convection in a complete-loss-of-pool-coolant event. The cask loading area in some pools may serve this purpose if it is in communication with the rest of the pool.

" Preinstalled emergency water makeup systems in spent fuel pools would provide a mechanism to replace pool water in the event of a coolant loss.

• Preinstalled water spray systems above or within the pool could also be used to..

cool the fuel in a loss-of-pool-coolant event.20 The committee carried out a simple aggregate calculation suggesting that a water spray of about 50 to 60 gallons (about 190 to 225 liters) per minute for the whole pool would likely be adequate to prevent a zirconium cladding fire in a loss-of-pool-coolant event. A simple, low-pressure spray distribution experiment could verify what distribution of coolant would be sufficient to cool a spent fuel pool. Such a system would have to be designed to function even if the spent fuel pool or building were severely damaged in an attack.2 '

Limiting full-core offloads to situations when such offloads are required would reduce the decay heat load in the pool during routine refueling outages.

Altematively, delaying the offload of fuel to the pool after a reactor shutdown would reduce the decay-heat load in the pool.

• The walls of spent fuel pools could be reinforced to prevent damage that could lead to a loss-of-pool-coolant event.

" Security levels at the plant could be increased during outages that involve core offloads.

Of course, damage to the pool and high radiation fields could make it difficult to take some of these mitigative measures. Multiple redundant and diverse measures may be required so that more than one remedy is available to mitigate a loss-of-pool-coolant event, especially when access to the pool is limited by damage or high radiation fields. Cost considerations might be significant, particularly for measures such as installing hardened spray systems and lengthening refueling outages, but the committee did not examine the costs of these measures.

3.3.3 Discussion The Sandia and ENTERGY analyses described in this chapter were still in progress when the committee completed its classified report. As noted previously, draft technical documents describing the work were not available at the time this study was being completed. Consequently, the committee's understanding of these analyses is based on briefing materials (i.e., PowerPoint slides) presented before the committee by Nuclear 20 There is an extensive analytic and experimental experience base confirming that spray systems are effective in providing emergency core cooling in BWR reactor cores, which generate much more decay heat than spent fuel. Detailed experiments have shown that some minimum amount of water must be delivered on top of each assembly, and if that is provided, the assembly will be cooled adequately even ifthere is significant blockage of the cooling channels.

21 ENTERGY staff mentioned the possible use of a specially equipped fire engine to provide spray cooling. The committee does not know whether this would deliver sufficient spray cooling where it is needed or would provide sufficient protection if terrorists are attempting to prevent emergency response, but the strategy is worth further examination.

56 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Regulatory Commission and ENTERGY staff and consultants, discussions with these experts, and the committee's own expert judgment.

The committee judges that these analyses provide a start for understanding the behavior of spent fuel pools in severe environments. The analyses were carried out by qualified experts using well-known analytical methods and engineering codes to model system behaviors. Although this is a start, the analyses have important limitations.

The aircraft attack scenarios consider one type of aircraft. Heavier aircraft could be used in such attacks. These planes are in common use in passenger and/or cargo operations, and some of these planes can be chartered.

Equally limiting assumptions were made in the analyses of spent fuel pool thermal behavior: To make the analysis tractable, it was assumed that the fuel in the pool was in an undamaged condition when the loss-of-pool-coolant event occurred. This is not necessarily a validassumption. Whether such damage would change the outcome of the analyses described in this chapter is unknown.

Simplistic modeling assumptions were made about the fuel assembly geometry (e.g.,

individual fuel bundles were not modeled in the global effects calculation), convective cooling flow paths and mechanisms, thermal radiation heat transfer, propagation of cladding fires to low-power bundles, and radioactivity release mechanisms. In addition, flow blockage due to fission-gas-induced clad ballooning2 was not considered. The thermal analysis experts on the committee judge that these simplistic assumptions could produce results that are more severe (i.e., overconservative) than would be the case had more realistic assumptions been used.

More sophisticated models, which involve clad ballooning and detailed thermal-hydraulics, including radiative heat transfer, have been developed for the analysis of severe in-core accidents. These models can be evaluated using more powerful computers.

MELCOR appears to have sufficient capability to evaluate more sophisticated models of the spent fuel pool and Sandia has access to large, sophisticated computers. State-of-the-art calculations of this type are needed for the analysis of spent fuel pools so that more informed regulatory decisions can be made.

The analyses also do not consider the possibility of an attack that ejects spent fuel from the pool. The ejection of freshly discharged spent fuel from the pool might lead to a zirconium cladding fire if immediate mitigative actions could not be taken. The application of such measures could be hindered by the high radiation fields around the fuel.

While the committee judges that some attacks involving aircraft would be feasible to carry out, it can provide no assessment of the probability of such attacks. Nevertheless, analyzing their consequences is useful for informing policy decisions on steps to be taken to protect these facilities from terrorist attack.

22 If a fuel rod reaches relatively high temperatures, the gases inside can cause the cladding to balloon out, restricting and even blocking coolant flow through the spaces between the rods within the assembly.

SPENT FUEL POOL STORAGE 57 3.4 FINDINGS AND RECOMMENDATIONS Based on its review of spent fuel pool risks, the committee offers the following findings and recommendations.

FINDING 3A: Pool storage is required at all operating commercial nuclear power plants to cool newly discharged spent fuel.

Operating nuclear power plants typically discharge about one-third of a reactor core of spent fuel every 18-24 months. Additionally, the entire reactor core may be placed into the spent fuel pool (offloaded) during outage periods for refueling. The analyses of spent fuel thermal behavior described in this chapter demonstrate that freshly discharged spent fuel generates too much decay heat to be passively air cooled. The Nuclear Regulatory Commission requires that this fuel be stored in a pool that has an active heat removal system (i.e., water pumps and heat exchangers) for at least one year as a safety matter.

Current design practices for approved dry storage systems require five years' minimum decay in spent fuel pools. Although spent fuel younger than five years could be stored in dry casks, the changes required for shielding and heat removal could be substantial, especially for fuel that has been discharged for less than about three years.

FINDING 3B: The committee finds that, under some conditions, a terrorist attack that partially or completely drained a spent fuel pool could lead to a propagating zirconium cladding fire and the release of large quantities of radioactive materials' to the environment. Details are provided in the committee's classified report.

It is not possible to predict the precise magnitude of such releases because the computer models have not been validated for this application.

FINDING 3C: It appears to be feasible to reduce the likelihood of a zirconium cladding fire following a loss-of-pool-coolant event using readily implemented measures.

There appear to be some measures that could be taken to mitigate the risks of spent fuel zirconium cladding fires in a loss-of-pool-coolant event. The following measures appear to have particular merit.

Reconfiguring of spent fuel in the pools (i.e., redistribution of high decay-heat

• assemblies so that they are surrounded by low decay-heat assemblies) to more evenly distribute decay-heat loads. The analyses described elsewhere in this chapter suggest that the potential for zirconium cladding fires can be reduced substantially by surrounding freshly discharged spent fuel assemblies with older spent fuel assemblies in "checkerboard" patterns. The analyses suggest that such arrangements might even be more effective for reducing the potential for 7irrnnh tr n dcdinn firpq than rprmnvinn thiq nlridr -qnpntfi il frmm fhcp nnrnl-

58 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE be made. The offloading of the reactor core into the spent fuel pool during reactor outages substantially raises the decay-heat load of the pool and increases the risk of a zirconium cladding fire in a loss-of-pool-coolant event. Of course, any actions that increase the time a power reactor is shut down incur costs, which must be considered in cost-benefit analyses of possible actions to reduce risks.

Development of a redundant and diverse response system to mitigate loss-of-pool-coolant events. Any mitigation system, such as a spray cooling system, must be capable of operation even when the pool is drained (which would result in high radiation fields and limit worker access to the pool) and the pool or overlying building, including equipment attached to the roof or walls, is severely damaged.

FINDING 3D: The potential vulnerabilities of spent fuel pools to terrorist attacks are plant-design specific. Therefore, specific vulnerabilities can be understood only by examining the characteristics of spent fuel storage at each plant.

As described in the classified report, there are substantial differences in the design of PWR and BWR spent fuel pools. PWR pools tend to be located near or below grade, whereas BWR pools typically are located well above grade but are protected by exterior walls and other structures. In addition, there are plant-specific differences among BWRs and PWRs that could increase or decrease the vulnerabilities of the pools to various kinds of terrorist attacks, making generic conclusions difficult.

FINDING 3E: The Nuclear Regulatory Commission and independent analysts have made progress in understanding some vulnerabilities of spent fuel pools to certain terrorist attacks and the consequences of such attacks for releases of radioactivity to the environment. However, additional work on specific issues listed in the following recommendation is needed urgently.

The analyses carried out to date for the Nuclear Regulatory Commission by Sandia National Laboratories and by other independent organizations such as EPRI and ENTERGY have provided a general understanding of spent fuel behavior in a loss-of-pool-coolant event and the vulnerability of spent fuel pools to certain terrorist attacks that could cause such events to occur. The work to date, however, has not been sufficient to adequately understand the vulnerabilities and consequences. This work has addressed a small number of plant designs that may not be representative of U.S. commercial nuclear power plants as a whole. It has considered only a limited number of threat scenarios that may underestimate the damage that can be inflicted on the pools by determined terrorists. Additional analyses are needed urgently to fill in the knowledge gaps so that well-informed policy decisions can be made.

RECOMMENDATION: The Nuclear Regulatory Commission should undertake additional best-estimate analyses to more fully understand the vulnerabilities and consequences of loss-of-pool-coolant events that could lead to a zirconium cladding fire. Based on these analyses, the Commission should take appropriate actions to address any significant vulnerabilities that are identified. The analyses of the BWR and PWR spent fuel pools should be extended to consider the consequences of loss-of-pool-coolant events that are described in the committee's classified report.

SPENT FUEL POOL STORAGE 59 The consequence analyses should address the following questions:

• To what extent would such attacks damage the spent fuel in the pool, and what would be the'thermal consequences of such damage?

• Is it feasible to reconfigure the spent fuel within pools to prevent zirconium cladding fires given the actual characteristics (i.e., heat generation) of spent fuel assemblies in the pool, even if the fuel were damaged in an attack? Is there enough space in the pools at all commercial reactor sites to implement such fuel reconfiguration?

• In the event of a localized zirconium cladding fire, will such rearrangement prevent its spread to the rest of the pool?

• How much spray cooling is needed to prevent zirconium cladding fires and prevent propagation of such fires? Which of the different options fO*r providing spray cooling are effective under attack and accident conditions?

Sensitivity analyses should also be undertaken to account for the full range of variation in spent fuel pool designs (e.g., rack designs, capacities, spent fuel burn-ups, and ages) at U.S. commercial nuclear power plants.

RECOMMENDATION: While the work described in the previous recommendation under Finding 3E, above, is being carried out, the Nuclear Regulatory Commission should ensure that power plant operators take prompt and effective measures to reduce the consequences of loss-of-pool-coolant events in spent fuel pools that could result in propagating zirconium cladding fires. The committee judges that there are at least two such measures that should be implemented promptly:

" -Reconfiguring of fuel in the pools so that high dec.'y-haat fuel assemblies are surrounded by low decay-heat assemblies. This will more evenly distribute decay-heat loads, thus enhancing radiative heat transfer in the event of a loss of pool coolant.

• Provision for water-spray systems that would be able to cool the fuel even if the pool or overlying building were severely damaged.

Reconfiguring of fuel in the pool would be a prudent measure that could probably be implemented at all plants at little cost, time, or exposure of workers to radiation.

The second measure would probably be more expensive to implement and may not be needed at all plants, particularly plants in which spent fuel pools are located below grade or are protected from external line-of-sight attacks by exterior walls and other structures.

The committee anticipates that the costs and benefits of options for implementing the second measure would be examined to help decide what requirements would be imposed. Further, the committee does not presume to anticipate the best design of such a system--whether it should be installed on the walls of a pool or deployed from a location where it is unlikely to be compromised by the same attack-but simply notes the demanding requirements such a system must meet.

4 DRY CASK STORAGE AND COMPARATIVE RISKS This chapter addresses the second and third charges of the committee's statement of task:

" The safety and security advantages, if any, of dry cask storage 1 versus wet pool storage at reactor sites.

" Potential safety and security advantages, if any, of dry cask storage using Various single-, dual-, or multi-purpose cask designs.

The second charge calls for a comparative analysis of dry cask storage versus pool storage, whereas the third charge focuses exclusively on dry casks. The committee will address the third charge first to provide the basis for the comparative analysis.

By the late 1970s, the need for alternatives to spent fuel pool storage was becoming obvious to both commercial nuclear power plant operators and the Nuclear Regulatory Commission. The U.S. government made a policy decision at that time not to support commercial reprocessing of spent nuclear fuel (see Appendix D). At the same time, efforts to open an underground repository for permanent disposal of commercial spent fuel were proving to be more difficult'and time consuming than originally anticipated. 2 Commercial nuclear power plant operators had no place to ship their growing inventories of spent fuel and were running out of pool storage space.

Dry cask storage was developed to meet the need for expanded onsite storage of spent fuel at commercial nuclear power plants. The first dry cask storage facility in the United States was opened in 1986 at the Surry Nuclear Power Plant in Virginia. Such facilities are now in operation at 28 operating and decommissioned nuclear power plants. In 2000, the nuclear power industry projected that up to three or four plants per year would run out of needed storage space in their pools without additional interim storage capacity.

This chapter is organized into the following sections:

0 Background on dry cask storage.

0 Evaluation of potential risks of dry cask storage.

• Potential advantages of dry storage over wet storage.

0 Findings and recommendations.

This storage system is referred to as "dry" because the fuel is stored out of water.

2 The Nuclear Waste Policy Act of 1982 and the Amendments Act of 1987 laid out a process for identifying a site for a geologic repository. That repository was to be opened and operating by the end of January 1998. The federal government now hopes to open a repository at Yucca Mountain, which is located in southwestern Nevada, by the end of 2010.

60

DRY CASK STORAGE AND COMPARA TIVE RISKS 61

4.1 BACKGROUND

ON DRY CASK STORAGE The storage of spent fuel in dry casks has the same three primary objectives as pool storage (Chapter 3):

• Cool the fuel to prevent heat-up to high temperatures from radioactive decay.

a Shield workers and the public from the radiation emitted by radioactive decay in the spent fuel and provide a barrier for any releases of radioactivity.

• Prevent criticality accidents.

Dry casks are designed to achieve the first two of these objectives without the use of water or mechanical systems. Fuel cooling is passive: that is, it relies upon a combination of heat conduction through solid materials and natural convection or thermal radiation through air to move decay heat from the spent fuel into the ambient environment. Radiation shielding is provided by the cask materials: Typically, concrete, lead, and steel are used to shield gamma radiation, and polyethylene, concrete, and boron-impregnated metals or resins are used to shield neutrons. Criticality control is provided by a lattice structure, referred to as a

• basket, which holds the spent fuel assemblies within individual compartments in the cask (FIGURE 4.1). These maintain the fuel in3 a fixed geometry, and the basket may contain boron-doped metals to absorb neutrons.

Passive cooling and radiation shielding are possible because these casks are designed to store only older spent fuel. This fuel has much lower decay heat than freshly discharged spent fuel as well as smaller inventories of radionuclides.

The industry sometimes refers to these casks using the following terms:

• Single-, dual-, and multi-purpose casks.

" Bare-fuel and canister-based casks.

The terms in the first bullet indicate the application for which the casks are intended to be used. Single-purpose cask systems are licensed4 only to store spent fuel. Dual-purpose casks are licensed for both storage and transportation. Multi-purpose casks are intended for storage, transportation, and disposal in a geologic repository. No true multi-purpose casks exist in the United States (or in any other country for that matter) because specifications for acceptable containers for geologic disposal have yet to be finalized by the Department of Energy. Current plans for Yucca Mountain do not contemplate the use of multi-purpose casks.

Nevertheless, some cask vendors still refer to their casks as'"multi-purpose." These are at best dual-purpose casks, however, because they have been licensed only for storage and transport. Because true multi-purpose casks do not now exist and are not likely to exist in the future, the committee did not consider them further in this study.

3 Criticality control is less of an issue in dry casks because there is no water moderator present after the cask is sealed and drained.

4Authority for licensing dry cask storage rests with the Nuclear Regulatory Commission.

62 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE FIGURE 4.1 Photo of NUHOMS canister showing the internal basket for holding the spent fuel assemblies in a fixed geometry. This canister is shown for illustrative purposes only.

SOURCE: Courtesy of Transnuclear, Inc., an Areva Company.

The terms in the second bullet indicate how spent fuel is loaded into the casks. In bare-fuel5 casks, spent fuel assemblies are placed directly into a basket that is integrated into the cask itself (see FIGURE 4.3B). The cask has a bolted lid closure for sealing. In canister-based casks, spent fuel assemblies are loaded into baskets integrated into a thin-wall (typically 1Y-inch [1.3-centimeter] thick) steel cylinder, referred to as a canister(see FIGURE 4.1 and 4.3A). The canister is sealed with a welded lid. The canister can be stored or transported if it is pla6ed within a suitable overpack. This overpack is closed with a bolted lid.

Bare-fuel and canister-based systems are sometimes referred to as "thick-walled" and "thin-walled" casks, respectively, by some cask vendors. This designation is not strictly correct because the overpacks in canister-based systems have thick walls. The only thin-walled component is the canister, which is designed to be stored or transported within the overpack.

The designation of a cask as single- or dual-purpose often has less to do with its design and more to do with licensing decisions. Indeed, bare-fuel and canister-based casks can be licensed for either single or dual purposes. Consequently, one should not expect the performance of a cask in accidents or terrorist attacks to depend on its designation as single- or dual-purpose. Rather, performance will depend on the type of attack and construction of the cask. For the purposes of discussion in this chapter, therefore, the committee uses the designations "bare-fuel" and "canister-based," rather than single- or dual-purpose, when referring to various cask designs.

All bare-fuel casks in use in the United States are designed to be stored vertically.

Most canister-based systems also are designed for vertical storage, but one overpack 5The term bare fuel refers to the entire fuel assembly, including the uranium pellets within the fuel rods.

DRY CASK STORAGE AND COMPARATIVE RISKS 63 system is designed as a horizontal concrete module (FIGURE 4.2).6 The principal characteristics of dry cask storage systems are summarized in TABLE 4.1, which is located at the end of this chapter.

Dry casks are designed to hold up to about 10 to 15 metric tons of spent fuel. This is equivalent to about 32 pressurized water nuclear reactor (PWR) spent fuel assemblies or 68 boiling water nuclear reactor (BWR) spent fuel assemblies. Although the dimensions vary among manufacturers, fuel types (i.e., BWR or PWR fuel), and amounts of fuel stored, the casks are typically about 19 feet (6 meters) in height, 8 feet (2.5 meters) in diameter, and weigh 100 tons or more when loaded.

The casks (for bare-fuel designs) or canisters (for canister-based designs) are placed directly into the spent fuel pool for loading. After they are loaded, the canisters or

.casks are drained, vacuum dried, and filled with an inert gas (typically helium). The loaded canisters or caski are then removed from the pool, their outer surfaces are decontaminated,7 and they are moved to the dry storage facility on the property of the reactor site. Loading of a single cask or canister can take up to one week. The vacuum drying process is the longest step in the loading process.

In the United States, dry casks are stored on open concrete pads within a protected area of the plant site.8 '9 This. protected area may be contiguous with the protected area of the plant itself or may be located some distance away in its own protected area (see FIGURE 2.1).

According to the information provided to the committee by cask vendors, nuclear power plant operators are currently purchasing mostly dual-purpose casks for spent fuel storage. The horizontal NUHOMS cask design is one of the most-ordered designs at present (TABLE 4.3). The vendors informed the committee that cost is the chief consideration for their customers when making purchasing decisions. Cost considerations are driving the cask industryaway from all-metal cask designs and toward concrete designs for storage.

6 In addition, there is one modular concrete vault design in the United States: the Fort St. Vrain, Colorado, Independent Spent Fuel Storage Installation, which stores spent fuel from a high-temperature gas-cooled reactor. This reactor operated until 1989 and is now decommissioned.

Because this is a one-of-a-kind facility, and the time available to the committee was short, it was not examined in this study.

7 Small amounts of radioactive contamination are present in the cooling water in the spent fuel pool.

Some of this contamination is transferred to the cask or canister surfaces when it is immersed in the tool for loading.

There may be exceptions in tfie future. Private Fuel Storage has requested a license from the Nuclear Regulatory Commission to construct a dry cask storage facility in Utah that will store fuel from multiple reactor sites. An underground dry cask storage facility has been proposed at the Humbolt Bay power plant in Califomia to store old, low decay-heat fuel. The underground design is being proposed primarily because the site has very demanding seismic design requirements and is possible only because the fuel to be stored generates little heat.

In Germany, dry casks are stored in reinforced concrete buildings. These buildings were originally designed to provide additional radiation shielding (beyond what is provided by the cask itself) to reduce doses at plant site boundaries to background levels. Some of these buildings are sufficiently robust to provide protection against crashes of large aircraft. A subgroup of the committee visited spent fuel storage sites at Ahaus and Lingen during this study. See Appendix C for details.

64 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE FIGURE 4.2 Photo showing a canister being loaded into a NUHOMS horizontal storage module. SOURCE: Courtesy of Transnuclear, Inc., an Areva Company.

4.2 EVALUATION OF POTENTIAL RISKS OF DRY CASK STORAGE Dry casks were designed to ensure safe storage of spent fuel, 10 not to resist terrorist attacks. The regulations for these storage systems, which are given in Title 10, Part 72 of the Code of Federal Regulations (i.e., 10 CFR 72), are designed to ensure adequate passive heat removal and radiation shielding during normal operations, off-normal events, and accidents. The latter include, for example, accidental drops or tip-overs during routine cask movements. The robust construction of these casks provides some passive protection against external assaults, but the casks were not explicitly designed with this factor in mind."

The regulations in 10 CFR 72 require that dry cask storage facilities (formally referred to as Independent Spent Fuel Storage Installations, or ISFSIs) be located within a protected area of the plant site (see FIGURE 2.1). However, the protection requirements for these installations are lower than those for reactors and spent fuel pools. The guard force is required to carry side arms, and its main function is surveillance: to detect and assess threats and to summon reinforcements. Ifthe ISFSI is within the protected area of the plant 10 Dual-purpose casks also were designed for safe transport under the requirements of Title 10, Part 71 of the Code of Federal Regulations. The committee did not examine transport of spent fuel in this study.

11 A recent study by the German organization GRS (Gesellschaft fOr Anlagen- und Reaktorsicherheit, MBH) examined the vulnerability of CASTOR-type casks to large-aircraft impacts.

DRY CASK STORAGE AND COMPARATIVE RISKS 65 it would come directly under the protection of plant's guard forces. The protected area is surrounded by vehicle barriers to protect against the detonation of a design basis threat vehicle bomb.12 A terrorist attack that breached a dry cask could potentially result in the release of radioactive material from the spent fuel into the environment through one or both of the following two processes: (1) mechanical dispersion of fuel particles or fragments; and (2) dispersion of radioactive aerosols (e.g., cesium-1 37). As described in Chapter 3, the latter process would have greater offsite radiological consequences. The committee evaluates the potential for both of these processes later in this chapter.

In the wake of the September 11, 2001, attacks, additional work has been or is being carried out by government and private entities to assess the security risks to dry casks from terrorist attacks. Sandia National Laboratories is currently analyzing the response of dry casks to a numb'br of potential terrorist attack scenarios at the request of the Nuclear Regulatory Comrhission. The committee was briefed on these analyses at two of its meetings.

Sandia is analyzing the responses of three vertical cask designs and one horizontal design to a variety of terrorist attack scenarios (FIGURE 4.3): These designs are considered to be broadly representative of the dry casks currently licensed for storage in the United States by the Nuclear Regulatory Commission (see TABLE 4.1 at the end of this chapter).

The committee received briefings on these studies by Nuclear Regulatory Commission and Sandia staff.

Several attack scenarios are being considered in the Sandia analyses. They include large aircraft impacts and assaults with various types and sizes of explosive charges and other energetic devices. Details on the large aircraft impact scenarios are provided in the classified report.

Most of this work is still in progress and has not yet resulted in reviewable documents. Consequently, the committee had to rely on discussions with the experts who are carrying out these studies and its own expert judgment in assessing the quality and completeness of this work.

4.2.1 Large Aircraft Impacts Sandia analyzed the impact of an airliner traveling at high speed into the four cask designs shown in FIGURE 4.3. These analyses examined the consequences of impacts of the fuselage and the "hard" components of the aircraft (i.e., the engines and wheel struts) into individual casks and arrays of casks on a storage pad. The latter analysis examined the potential consequences of cask-to-cask interactions resulting from cask sliding or partial tip-over. The objectives of the analyses were first to determine whether the casks would fail (i.e., the containment would be breached) and, if so, to estimate the radioactive material releases and their health consequences.

12 As noted in Chapter 2, the committee did not examine surveillance requirements or the placement or effectiveness of vehicle barriers and guard stations at commercial nuclear plants.

66 SAFET 6YAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 41n np.

M B

j IM~

"U

&tYILI WSOAM 10OWWAC C D

.dD-.A.y.y NUHOMSM&32P VSC4O.C~F~nOwMPACK ed in the Sandia analyses described in this chapter: (A)

FIGURE 4.3 Four cask systems u: The casks shown in A, C. and HI-STORM-1 00, (B) TN-68, (C) V,' Z-24, (D) NUHOMS-32P.

D are canister-based casks; the c; -isk shown in B is a bare-fuel cask. SOURCE: Nuclear Regulatory Commission briefing n *aterials (2004).

The aircraft was modeled t .ising 'Sandia-developed Eulerian CTH code (see footnote 15 in Chapter 3). The aircraft man ..facturer (Boeing Corp.) was consulted to ensure that the aircraft model used in the analyse 3 was accurate. The casks were modeled with standard finite element codes using the put -lished characteristics of the casks. The casks were assumed to be filled with high-bur i-up, 10-year-old spent fuel. The fuel rods were assumed to fail (rupture) if the strains in the cladding exceeded 1 percent, which is a conservative release of radioactive materials from the spent fuel assumption. Sandia evaluated the pellets inside the fuel rods when s uch cladding failures occurred. Radiological consequences of such releases w are calculated for "representative" (with respect to weather and population) site conditions for each cask based on the actual average conditions at the

DRY CASK STORAGE AND COMPARATIVE RISKS 67

.13 site that currently stores the most spent fuel in that cask type.13 Site conditions differed for each cask.

The effects of jet fuel fires also were not considered in the analyses. Based on an analysis of actual aircraft accidents, Sandia determined that jet fuel would likely be dispersed over a large area in a low-angle impact. Consequently, the resulting petroleum fire would likely be of short duration (generally less than 15 minutes according to Sandia researchers). Long-duration fires that could damage the casks or even ignite the cladding of the spent fuel were not seen to be credible for the aircraft impact scenarios considered by Sandia.' 4 The results of these analyses, which are considered by the Nuclear Regulatory Commission to be classified or safeguards information, are detailed in the classified report.

In general, the analyses show that some types of impacts will damage some types of casks.

For some scenarios there could be substantial cask-to-cask interactions, including collisions and partial tip-overs.

Nevertheless, predicted releases of radioactive material from the casks, mainly noble gases, were relatively small for all of the scenarios considered by Sandia. The analyses show that the releases were governed by design-specific features of the casks. Sandia noted that the modeling of such releases is difficult and requires expert judgment for several elements of the calculation. Detailed calculations of the consequences were still in progress when the committee was briefed on these analyses.

4.2.2 Other Assaults Analyses are also being carried out to understand the consequences of other types of assaults on the cask designs shown in FIGURE 4.3. These include assaults using explosives and certain types of high-energy devices. The analyses were still underway when the committee was briefed on these analyses, and the results were characterized by the Nuclear Regulatory Commission as preliminary. Details are provided in the classified report.

4.2.3 Discussion As noted previously, the dry cask vulnerability analyses were still underway when the committee's classified study was completed. Based on the analyses it did receive, the committee judges that no cask provides complete protection against all types of terrorist attacks. The committee judges that releases of radioactive material from dry casks are low for the scenarios it examined with one possible exception as discussed in the classified report. It is not clear to the committee whether it is credible to assume that this "exceptional" scenario could actually be carried out.

13 As noted in Chapter 1, the committee did not concern itself with how radioactive materials would be transported through the environment once they were released from a dry cask. Rather, the committee confined its examination to whether and how much radioactive material might be released from a dry cask in the event of a terrorist attack.

14 The committee subgroup that visited Germany was briefed on a fire test on the Castor cask that involved a fully engulfing one-hour petroleum fire. The cask maintained its integrity during and after this test. See Appendix C. The results of this test do not necessarily translate to casks having other designs.

68 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE

. In the committee's opinion, there are several relatively simple steps that could be taken to reduce the likelihood of releases of radioactive material from dry casks in the event of a terrorist attack:

• Additional surveillance could be added to dry cask storage facilities to detect and thwart ground attacks.1 5

• Certain types of cask systems could be protected against aircraft strikes by partial earthen berms. Such berms also would deflect the blasts from vehicle bombs.

• Visual barriers could be placed around storage pads to prevent targeting of individual casks by aircraft or standoff weapons.1 6 These would have to be designed so that they would not trap jet fuel in the event of an aircraft attack.

• The spacing of vertical casks on the storage pads can be changed, or spacers (shims) can be placed between the casks, to reduce the likelihood of cask-to-cask interactions in the event of an aircraft attack.

• Relatively minor changes in the design of newly manufactured casks could be made to improve their resistance to certain types of attack scenarios.

4.3 POTENTIAL ADVANTAGES OF DRY STORAGE OVER WET STORAGE Based on the analyses presented in Chapter 3 and previously in this chapter, the committee judges that dry cask storage has several potential safety and security advantages over pool storage. These differences can best be illustrated using scenarios for both storage systems based on the Sandia analyses reviewed by the committee. The use of such scenarios should not be taken to imply that the committee believes that these scenarios are likely or even possible at all storage facilities. They are used only for illustrative purposes.

The following statements can be made about the comparative advantages of dry-cask storage and pool storage based on the Sandia analyses:

Less spent fuel is at risk in an accident or attack on a dry storage cask than on a spent fuel pool. An accident or attack on a dry cask storage facility would likely affect at most a few casks and put a few tens of metric tons of spent fuel at risk. An accident or attack on a spent fuel pool puts the entire inventory of the pool, potentially hundreds of metric tons of spent fuel, at risk.

The potential consequences of an accident or terrorist attack on a dry cask storage facility are lower than those for a spent fuel pool. There are several reasons for this difference:

(1) There is less fuel in a dry cask than in a spent fuel pool and therefore less radioactive material available for release.

(2) Measuredon a per-fuel-assembly basis, the inventories of radionuclides available 15 As noted in Chapter 1, the committee did not examine surveillance activities at nuclear power ISFSIhas 6The and plants at no Palo to the basis judgeNuclear Verde current activities at dry cask storage facilities are adequate.

whetherPower Plant in Arizona, which was visited by a subgroup of committee members, incorporates a berm into its design to provide a visual barrier.

DRY CASK STORAGE AND COMPARATIVE RISKS 69 for release from a dry cask are lower than those from a spent fuel pool because dry casks store older, lower decay-heat fuel.

(3) Radioactive material releases from a breach in a dry cask would occur through mechanical dispersion. 17 Such releases would be relatively small.- Certain types of attacks on spent fuel pools could result in a much larger dispersal of spent fuel fragments. Radioactive material releases from a spent fuel pool also could occur as the result of a zirconium cladding fire, which would produce radioactive aerosols. Such fires have the potential to release large quantities of radioactive material to the environment.

The recovery from an attack on a dry cask would be much easier than the recovery from an attack on a spent fuel pool. Breaches in dry casks could be temporarily plugged with radiation-absorbing materials until permanent fixes or replacements could be made. The most significant contamination would likely be confined largely to areas near the cask storage padcand could be detected and decontaminated. The costs of recovery could be high, however, especially if the cask could not be repaired or the spent fuel could not be removed with equipment available at the plant. A special facility might have to be constructed or brought onto the site to transfer the damaged spent fuel to other casks.

Breaches in spent fuel pools could be much harder to plug, especially if high radiation fields or the collapse of the overlying building prevented workers from reaching the pool. Complete cleanup from a zirconium cladding fire would be extraordinarily expensive, and even after cleanup was completed large areas downwind of the site might remain contaminated to levels that prevented reoccupation (see Chapter 3).

It is the potential for zirconium cladding fires in spent fuel pools that gives dry cask storage most of its comparative safety and security advantages. This comparative advantage can be reduced by lowering the potential for zirconium cladding fires in loss-of-pool-coolant events. As discussed in Chapter 3, the committee believes that there are at least two steps that can be implemented immediately to lower the potential for such fires.

4.4 FINDINGS AND RECOMMENDATIONS With respect to the committee's task to examine potential safety and security advantages of dry cask storage using various single-, dual-, or multi-purpose cask designs, the committee offers the following findings and recommendations:

FINDING 4A: Although there are differences in the robustness of different dry cask designs (e.g., bare-fuel versus canister-based), the differences are not large when measured by the absolute magnitudes of radionuclide releases in the event of a breach.

All storage cask designs are vulnerable to some types of terrorist attacks for which radionuclide releases would be possible. The vulnerabilities are related to the specific 17 Since the committee's classified report was published, the committee received an additional briefing from the Nuclear Regulatory Commission suggesting that a radioactive aerosol could be released in one type of terrorist attack. However, the scenario in question does not appear.to the committee to be credible.

70 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE design features of the casks, but the committee judges that the quantity of radioactive material releases predicted from such attacks is still relatively small.

FINDING 4B: Additional steps can be taken to make dry casks less vulnerable to

• potential terrorist attacks.

Although the vulnerabilities of current cask designs are already small, additional,

.relatively simple.steps can be taken to reduce them. Such steps are listed in Section 4.2.3.

RECOMMENDATION: The Nuclear Regulatory Commission should consider using the results of the vulnerability analyses for possible upgrades of requirements in 10 CFR 72 for dry casks, specifically to improve their resistance to terrorist attacks.

The committee was told by Nuclear Regulatory Commission staff that such a step is already under consideration. Based on the material presented to the committee, there appear to be minor changes that can be made by plant operators and cask vendors to increase the resistance of existing and new casks to terrorist attacks (see Section 4.2.3).

With respect to the committee's task to examine the safety and security advantages of dry cask storage versus wet pool storage at reactor sites, the committee offers the following findings and recommendations:

FINDING 4C: Dry cask storage does not eliminate the need for pool storage at operating commercial reactors.

Newly discharged fuel from the reactor must be stored in the pool for cooling, as discussed in detail in Chapter 3. Under current U.S. practices, dry cask storage can be used only to store fuel that has been out of the reactor long enough (generally greater than five years under current practices) to be air cooled. The fuel in dry cask storage poses less of a risk in the event of a terrorist attack than newly discharged fuel in pools because there is substantially reduced probability of initiating a cladding fire.

FINDING 4D: Dry cask storage for older, cooler spent fuel has two inherent advantages over pool storage: (1) It is a passive system that relies on natural air circulation for cooling; and (2) it divides the inventory of that spent fuel among a large number of discrete, robust containers. These factors make it more difficult to attack a large amount of spent fuel at one time and also reduce the consequences of such attacks.

Each storage cask holds no more than about 10 to .15 metric tons of spent fuel, compared to the several hundred metric tons of spent fuel that is commonly stored in reactor pools. The robust construction of these casks prevents large-scale releases of radionuclides in all of the attack scenarios examined by the committee. Some of the attacks could breach the casks, but many of these breaches would be small and could probably be more easily plugged than a perforated spent fuel pool wall because radiation fields would be lower and there would be no escaping water to contend with. Even large breaches of the cask would

DRY CASK STORAGE AND COMPARATIVE RISKS 71 result only in the mechanical dispersal of some of its radionuclide inventory in the immediate vicinity of the cask.

FINDING 4E: Depending on the outcome of plant-specific vulnerability analyses described in the committee's classified report, the Nuclear Regulatory Commission might determine that earlier movements of spent fuel from pools into dry cask storage would be prudent to reduce the potential consequences of terrorist attacks on pools at some commercial nuclear plants.

The statement of task directs the committee to examine the risks of spent fuel storage options and alternatives for decision makers, not to recommend whether any spent fuel should be transferred from pool storage to cask storage. In fact, there may be some commercial plants that, because of pool designs or fuel loadings, may require some removal of spent fuel from-their pools. Ifthere is a need to remove spent fuel it should become clearer once the vulnerability and consequence analyses described in Chapter 3 are completed. The committee expects that cost-benefit considerations would be a part of these analyses.

-.4 TABLE 4.1 Dry Casks Used for Spent Fuel Storage in the United States Cask design License holder Type Fuel type Construction Closure system Number of casks used to used for date; sites; and number storage of casks on order' CASTOR V/21 GNSI (General Bare-fuel, BWR Ductile cast iron Primarv lid (44 bolts) (Sur In25loRadrr %n Nuclear Systems, storage-only secondary lid (48 bolts) purchased Inc.)

CASTOR X/33 GNS (Gesellschaft Bare-fuel, PWR Ductile cast iron Primary lid (44 bolts), I loaded (Surry); 0 fOr Nuklear-Service storage-only secondary lid (70 cup purchased mbH) screws)

NAC S'T NAC International Bare-fuel, PWR Inner and outer Closure lid (24 bolts) 2 loaded (Surry); 0 storage-only stainless steel purchased shells

-n MC-10 Westinghouse Bare-fuel, PWR Stainless and One shield lid and two I loaded (Surry); 0 0 storage-only carbon steel sealing lids, all bolted purchased (number of bolts not available)

TN-32, TN-40 Transnuclear Inc. Bare-fuel, PWR Carbon steel One lid (48 bolts) 61 loaded (4 sites); 22 0 storage-only purchased -n TN-68 Transnuclear Inc. Bare-fuel, BWR Carbon steel One lid (48 bolts) 24 loaded (Peach dual-purpose Bottom); 20 purchased C/)

Fuel Solution BNFL Fuel Canister- PWR, Reinforced Canister lid, welded 7 loaded (Big Rock W-150 Solutions based, dual- BWR concrete with inner cask lid (12 bolts) Point); 0 purchased Storage Cask purpose steel shell 0 HI-STORM Holtec International Canister- PWR, Stainless steel Canister lid, welded 58 loaded (7 sites); 177 100 based, BWR shells with un- cask lid (4 bolts) on order storage-only reinforced Cr) module concrete filler HI-STAR 100 Holtec International Canister- PWR, Carbon steel Canister lid, welded 7 loaded (2 sites1 ); 5 on based, dual- BWR shells with neutron cask lid (54 bolts) order purpose absorber polymer

VSC-24 BNFL Fuel Canister- PWR Reinforced Canister lid, welded 58 loaded 13 sites); 4 Ventilated Solutions based, concrete with inner cask lid (6 bolts) purchased Concrete Cask storage-only steel shell 02 NAC-MPC NAC International Canister- PWR Metal canister Canister lid, welded 21 loaded (Yankee Rowe based, dual- surrounded by cask lid over a shield plug and CT Yankee); 59 purpose storage overpack. (6 high-strength bolts) purchased Storage overpack consists of an G) inner steel liner 3.5 in. thick, two rebar cages, and 0 concrete NAC-UMS NAC International Canister- PWR, Metal canister Canister lid, welded 80 loaded (2 sites); 165 based, dual- BWR surrounded by cask lid over a shield plug purchased purpose storage overpack. (6 high-strength bolts)

Storage overpack consists of Inner ito.

steel liner 2.5 in.

thick, two rebar cages, and concrete Holtec MPC Holtec International Canister PWR, Metal canister Canister lid, welded 34 loaded (Trojan); 0 24E/EF based, dual- BWR surrounded by cask lid, shield plug plus purchased purpose storage overpack. 48 bolts Storage overpack consists of inner and outer steel liners, a double-rebar cage, and concrete NUHOMS Transnuclear Inc. Canister- PWR, Horizontal Canister lid, welded 239 loaded (10 sites);

24P, 52B, based, dual- BWR reinforced storage module lid, >150 purchased 61BT, 24PT1, purpose concrete storage reinforced concrete 24PT2, 32PT module with shielded canister

,= _ _

N NOTES:

1The Humboldt Bay Power Plant is licensing a site-specific variation of the HI-STAR System called HI-STAR HB.

2 Some licensees have purchased additional casks that have not yet been loaded, nor are they planned for loading.

SOURCES: Data compiled from cask license holders (2004).

0 00nC 0

Co Pn

-n

-I

5 IMPLEMENTATION ISSUES Implementation of the recommendations in this report will require actions and cooperation by a large number of parties. This chapter provides a brief discussion of two implementation issues that the committee believes will be of interest to Congress:

(1) Timing Issues: Ensuring that high-quality, expert analyses are completed in a timely manner.

(2) Communication Issues: Ensuring that the results of the analyses are communicated to industry so that appropriate and timely mitigating actions can be taken.

5.1 TIMING ISSUES The September 11, 2001, terrorist attacks forced the nation to begin a reexamination of the vulnerability of its critical infrastructure to high-impact suicide attacks by terrorists. The Nuclear Regulatory Commission was no exception. The Commission began a top-to-bottom review of security procedures at commercial nuclear power plants. This review resulted in the issuance of numerous directives to power plant operators to upgrade their security practices. The Commission also began a series of vulnerability analyses of spent fuel storage to terrorist attacks. These analyses are described in Chapters 3 and 4.

More than three years have passed since the September 11, 2001, attacks.

Vulnerability analyses of spent fuel pool storage to attacks with large aircraft have been performed by EPRI (Chapter 3), and analyses of vulnerabilities of dry cask storage to large aircraft attacks have been completed by the German organization GRS (Gesellschaft for Anlagen- und Reaktorsicherheit, mbH). However, the Nuclear Regulatory Commission's analyses of spent fuel storage vulnerabilities have not yet been completed, and actions to reduce vulnerabilities, such as those described in Chapter 3, on the basis of these analyses have not yet been taken. Moreover, some important additional analyses remain to be done.

The slow pace in completing this work is of concern given the enormous potential consequences as described elsewhere in this report.

The committee does not know the reason for this delay, nor was it asked by Congress for an evaluation. It is important to note that the Nuclear Regulatory Commission's analyses are addressing a much broader range of vulnerabilities than just spent fuel storage. The committee nevertheless raises this issue because it appears to be having an impact on the timely completion of critical work and implementation of appropriate mitigative actions for spent fuel storage.

5.2 COMMUNICATION ISSUES During the course of this study, the committee had the opportunity to interact with representatives of the nuclear power industry to discuss their concerns about safety and 75

76 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE security issues. The committee received numerous comments from industry representatives about the lack of information sharing by the Nuclear Regulatory Commission on the vulnerability analyses described in Chapter 3. These representatives noted that information flow was predominately in one direction: from the industry to the Commission. The Commission was not providing a reciprocal flow of information that could help the industry better understand and take early actions to address identified vulnerabilities.

Restrictions on information sharing by the Commission have resulted in missed opportunities in at least two cases observed by the committee. Analyses of aircraft impacts into power plant structures described in Chapter 3 were being carried out independently by Sandia for the Commission and by EPRI for the nuclear power industry. Because of classification restrictions, EPRI was not provided with information about the Sandia work, including the results of physical tests that would have helped EPRI validate its models. Both Sandia and the industry would have benefited had their analysts been able to talk with each other about their models, assumptions, and results while the analyses were in progress.

When the EPRI work was completed the Commission declared it to be safeguards "

information.' As a consequence, some of the EPRI analysts who generated the results no longer had access to them, and the results could not be shared widely within industry.

A similar situation exists with respect to the ENTERGY Corp. spent fuel pool separate effects analyses described in Chapter 3. ENTERGY is using similar approaches and models as Sandia but has received little or no guidance from Commission staff about whether the results are realistic or consistent. The ENTERGY analysts told the committee that they would have benefited had they been able to compare and discuss their approaches and results with Sandia analysts. Sandia analysts were prevented from doing so because of classification issues. Sharing of ENTERGY's results within the company or across industry may be problematical if they are determined to be classified or safeguards information by the Commission.

Several Nuclear Regulatory Commission staff also privately expressed to the committee their frustration at the difficulty in sharing information that they know would be useful to industry. In fact, from the contacts the committee had, there does not appear to be a lack of willingness to share information at the working staff level within the Commission.

Rather, it seems to be an issue of getting permission from upper management and addressing the classification restrictions.

Much of the difficulty in sharing this information appears to arise because the information is considered by the Nuclear Regulatory Commission to be safeguards information or in some cases even classified national security information. Industry analysts and decision makers generally do not have the appropriate personal security clearances 2 to access this information. The committee learned that the Commission is making efforts to share more of this information with some industry representatives. The industry will be responsible for implementing any changes to spent fuel storage to make it less vulnerable to terrorist attack. Clearly, therefore, the industry needs to understand the results of the Safeguards information is defined in section 147 of the Atomic Energy Act and in the Code of Federal Regulations, Title 10, Part 73.2. See the glossary for a definition. Authority for designation of safeguards resides with the Nuclear Regulatory Commission.

2 In fact, a personnel security clearance is not required to access safeguards information. One only needs to be of "good character" and have a "need to know" as determined by the Nuclear Regulatory Commission.

IMPLEMENTATION ISSUES 77 Commission's vulnerability analyses to ensure that effective implementation strategies are adopted.

The committee also received complaints during this study from members of the public about the lack of information sharing. Commission staff have responded to these complaints by stating that such sharing could reveal sensitive information to terrorists and that the public does not have a "need to know" this information.

The committee fully agrees that information that could prove useful to terrorists should not be released. On the other hand, the committee believes that there is information that could be shared without compromising national security. For example, general information about the kinds of threats being considered and general steps being taken to reduce vulnerabilities could be shared with the public. Information about specific vulnerabilities of spent fuel pools and dry storage casks to terrorist attacks as well as potential mitigative actions could be shared with industry without revealing the details about how such attacks brnight be carried out. Sharing information with industry is essential for ensuring that mitigative actions to reduce vulnerabilities are carried out. Sharing information with the public is essential in a nation with strong democratic traditions for sustaining public confidence in the Commission as an effective regulator of the nuclear industry, and for reducing the potential for severe environmental, health, economic, and psychological consequences from terrorist attacks should they occur.

5.3 FINDING AND RECOMMENDATION FINDING 5A: Security restrictions on sharing of information and analyses are hindering progress in addressing potential vulnerabilities of spent fuel storage to terrorist attacks.

Current classification and security practices *appearto discourage information sharing between the Nuclear Regulatory Commission and industry. During the course of the study the committee received comments from power plant operators, their contractors, and Nuclear Regulatory Commission staff about the difficulties of sharing the information on the vulnerability of spent fuel storage. Indeed, even the committee found it difficult and in some cases impossible to obtain needed information (e.g., information on the design basis threat).

Such restrictions have several negative consequences: They impede the review and feedback processes that can enhance the technical soundness of the analyses being carried out; they make it difficult to build support within the industry for potential mitigative measures; and they may undermine the confidence that the industry, expert panels such as this one, and the public place in the adequacy of such measures.

RECOMMENDATION: The Nuclear Regulatory Commission should improve the sharing of pertinent information on vulnerability and consequence analyses of spent fuel storage with nuclear power plant operators and dry cask storage system vendors on a timely basis.

Implementation of this recommendation will allow timely mitigation actions.

Certain current security practices may have to be modified to carry out this recommendation.

78 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE The committee also believes that the public is an important audience for the work being carried out to assess and mitigate vulnerabilities of spent fuel storage facilities. While it would be inappropriate to share all information publicly, more constructive interaction with the public and independent analysts could improve the work being carried out and also increase public confidence in Nuclear Regulatory Commission and industry decisions and actions to reduce the vulnerability of spent fuel storage to terrorist threats.

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USNRC. 2001a. Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants. NUREG-1738. Division of Systems Safety and Analysis. January.

Washington, D.C.

USNRC. 2001b. Review of NRC's Dry Cask Storage Program. Audit Report. OIG-01-A-11.

Office of the Inspector General. June 20. Washington, D.C.

82 SAFETYAND SECURITY OFCOMMERCIAL SPENT FUEL STORAGE USNRC. 2003a. Nuclear Regulatory Commission (NRC) review of"Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States." Science and Global Security, Vol. 11, pp. 2 0 3 -2 1 1 .

USNRC. 2003b. A Prioritization of Generic Safety Issues. NUREG-0933. R. Emrit, R. Riggs, W.

Milstead, J. Pittman, and H. Vendermolen. Office of Nuclear Regulatory Research.

October. Washington, DC. Available at http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933.

Walker, J.S. 2004. Three Mile Island: A Nuclear Crisis in Historical Perspective. University of California Press. Berkeley, California.

Zimmerman, P. D., and C. Loeb. 2004. Dirty Bombs: The Threat Revisited. Defense Horizons.

Vol. 38 (January), pp. 1-11.

A INFORMATION-GATHERING SESSIONS The committee organized several meetings and tours to obtain information about the safety and security of spent fuel storage. A list of these meetings and tours is provided below. The committee held several data-gatheringsessions not open to the public to obtain classified and safeguards information about the safety and security of spent fuel storage.

The committee also held several data-gatheringsessions open to the public to receive unclassified briefings from industry, independent analysts, and other interested parties including members of the public. The written materials (e.g., PowerPoint presentations and written statements) obtained by the committee at these open sessions are posted on the web site for this project: http://dels.nas.edu/sfs.

A.1 FIRST MEETING, FEBRUARY 12-13, 2004, WASHINGTON, D.C.

The objective of this meeting was to obtain background information on the study request from staff of the House Committee on Appropriations, Energy and Water Development Subcommittee. The committee also was briefed by one of the sponsors of the study and by two independent experts. The following is the list of topics and speakers for the open session:

• Background on the congressional request for this study. Speaker: Kevin Cook, Professional Staff, House Committee on Appropriations, Energy and Water Development Subcommittee.

• Reducing the hazard from stored spent power-reactor fuel in the United States.

Speakers: Frank von Hippel, Princeton University, and Klaus Janberg, independent consultant, co-authors of the paper entitled "Reducing the Hazard from Stored Spent Power-Reactor Fuel in the United States" (Alvarez et al.,

2003).

0 Nuclear power plants and their fuel as terrorist targets. Speaker: Ted Rockwell, MPR Associates, Inc., co-author of the paper entitled "Nuclear Power Plants and Their Fuel as Terrorist Targets" (Chapin et al., 2002).

• Nuclear Regulatory Commission analyses of spent fuel safety and security.

Speaker: Farouk Eltawila, director, Division of Systems Analysis and Regulatory Effectiveness, Office of Research, Nuclear Regulatory Commission.

On the second day of the meeting, the committee held a data-gathering session not open to the public to obtain classified briefings from the U.S. Nuclear Regulatory Commission about its ongoing analyses of spent fuel storage security.

A.2 SECOND MEETING, MARCH 4-6, 2004, ARGONNE, ILLINOIS During the second meeting, the committee held a data-gathering session not open to the public to receive classified briefings on spent fuel storage security from the U.S. Nuclear Regulatory Commission. The committee also toured the Dresden and Braidwood Nuclear 83

84 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Generating Stations to see first-hand how spent fuel is managed and stored. The two plants were chosen because of the differences in their spent fuel storage facilities.

A.3 THIRD MEETING, APRIL 15-17, 2004, ALBUQUERQUE, NEW MEXICO During the third meeting, the committee held a data-gathering session not open to the public to receive a briefing from EPRI on spent fuel storage vulnerabilities. The committee also held a data-gathering session open to the public to receive briefings on dry cask storage systems and radioactive releases from damaged spent fuel storage casks.

" Speakers on dry cask storage systems: William McConaghy (GNB-GNSI);

Steven Sisley (BNFL); Alan Hanson (Transnuclear Inc.); Charles Pennington (NAC International); and Brian Gutherman (Holtec International, via telephone).

• Radionuclide releases from damaged spent fuel. Speaker: Robert Luna, Sandia National Laboratories (retired).

A.4 TOUR OF SELECTED SPENT FUEL STORAGE INSTALLATIONS IN GERMANY On April 25-28, 2004, a group of committee members traveled to Germany to meet with German officials and to visit selected spent fuel storage installations. The agenda of the tour was as follows:

• Meeting with Michael Sailer, chairman of the German reactors safety commission (RSK, Reaktorsicherheitskommission).

• Visit to the dry cask manufacturer GNB (Gesellschaft for Nuklear-Beh~lter mbH) headquarters in Essen and the cask assembly facility and test museum in M0lheim.

• Tour of the Ahaus intermediate dry storage facility.

• Meeting with Florentin Lange, GRS (Gesellschaft for Anlagen- und Reaktorsicheheit mbH), co-author of the study entitled "Safety Margins of Transport and Storage Casks for Spent Fuel Assemblies and HAW Canisters Under Extreme Accident Loads and Effects from External Events" (Lange et al.,

2002).

• Tour of the Lingen nuclear power plant and its spent fuel storage facilities.

A summary of information gathered during the tour is provided in Appendix C.

A.5 FOURTH MEETING, MAY 10-12, 2004, WASHINGTON, D.C.

During the fourth meeting, the committee held a data-gathering session not open to the public to hold in-depth technical discussions with Sandia National Laboratories staff and contractors on their spent fuel storage vulnerability analyses. The committee also received an intelligence briefing from Department of Homeland Security staff on terrorist capabilities and from the U.S. Nuclear Regulatory Commission staff on terrorist scenarios.

The meeting also included a data-gathering session open to the public that included the following briefings:

INFORMATION-GATHERING SESSIONS 85

" Summary of the field trip to Germany. Speaker: Louis Lanzerotti (committee chair).

• Vulnerabilities of spent nuclear fuel pools to terrorist attacks: Issues with the design basis threat. Speaker: Peter Stockton, Project on Government Oversight.

• Consequences of a major release of 137Cs into the atmosphere. Speaker: Jan Beyea, Consulting in the Public Interest.

A.6 FIFTH MEETING, MAY 26-28, 2004, WASHINGTON, D.C.

The objective of this closed meeting (i.e., open only to committee members and staff) was to finalize the classified report for National Research Council review.

A.7 TOURS OP SELECTED SPENT FUEL STORAGE FACILITIES AT U.S. NUCLEAR POWER PLANTS On June 11 and June 14, 2004, respectively, committee subgroups visited the Palo Verde Nuclear Generating Station in Arizona and the Indian Point Nuclear Generating Station in New York.

A.8 SIXTH MEETING, JUNE 28-29, 2004 The objective of this closed meeting was to complete work on the classified report.

A.9 SEVENTH MEETING, AUGUST 12-13, 2004 The objective of this closed meeting was to develop a public version of the committee's report. The committee also held a data-gathering session not open to the public to receive a briefing from the Department of Homeland Security on steps being taken to address the findings and recommendations in the classified report.

A.10 EIGHTH MEETING, OCTOBER 28-29, 2004 The objective of this closed meeting was to continue work to develop a public version of the committee's report. The committee also held a data-gathering session not open to the public to receive a briefing from the Nuclear Regulatory Commission on steps being taken to address the findings and recommendations in the classified report.

A.11 NINTH MEETING, NOVEMBER 29-30, 2004 The objective of this closed meeting was to continue work to develop a public version of the committee's report.

86 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE A.12 TENTH MEETING, January 24-25, 2005 The objective of this closed meeting was to continue work to develop a public version of the committee's report. The committee also held a data-gathering session not open to the public to meet with three c6mmissioners from the Nuclear Regulatory Commission (Chairman Nils Diaz and members Edward McGaffigan and Jeffrey Merrifield) to discuss what additional information the commission might be willing to make available to the committee on human-factors-related issues.

REFERENCES Alvarez, R., J. Beyea, K. Janberg, J. Kang, E. Lyman, A. Macfarlane, G. Thompson, and F.

N. von Hippel. 2003a. Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States. Science and Global Security, Vol. 11, pp. 1-51 Chapin, D. M., K. P. Cohen, W. K. Davis, E. E. Kintner, L. J. Koch, J. W. Landis, M.

Levenson, I. H. Mandil, Z. T. Pate, T. Rockwell, A. Schriesheim, J. W. Simpson, A.

Squire, C. Starr, H. E. Stone, J. J. Taylor, N. E. Todreas, B. Wolfe, and E. L.

Zebroski. 2002. Nuclear Power Plants and Their Fuel as Terrorist Targets. Science, Vol. 297, pp. 1997-1999.

Lange, F., H. J. Fett, E. Hormann, E. Schrodl, G. Schwarz, B. Droste, H. Volzke, G. Wieser, and L. Qiao. 2002. Safety Margins of Transport and Storage Casks for Spent Fuel Assemblies and HAW Canisters under Extreme Accident Loads and Effects from External Events. Report within framework of Project SR 2415. April. Gesellschaft fOr Anlagen- und Reaktorsicherheit (GRS) mbH, Koln; Bundesanstalt fOr Materialforschung und -prOfung (BAM), Berlin, Germany.

B BIOGRAPHICAL SKETCHES OF COMMITTEE MEMBERS LOUIS J. LANZEROTTI, Chair,is an expert in geophysics and electromagnetic waves and a veteran of over 40 National Research Council (NRC) studies. He currently consults for Bell Laboratories, Lucent Technologies, and is a distinguished professor for solar-terrestrial research at the New Jersey Institute of Technology. Previously, he was a distinguished member of the technical staff at Bell Labs. His research interests include space plasmas and engineering problems related to the impacts of atmospheric and space processes on telecommunications on commercial satellites and transoceanic cables. He has been associated with numerous National Aeronautics and Space Administration (NASA) space missions as well,Jncluding Voyager, Ulysses, Galileo, and Cassini, and with commercial space satellite missions to research design and operational problems associated with spacecraft and cable operations. In 1988, he was elected to the National Academy of Engineering for his work on energetic particles and electromagnetic waves in the earth's magnetosphere, including their impact on space and terrestrial communication systems. He has twice received the NASA Distinguished Public Service Medal and has a geographic feature in Antarctica named in his honor. He was appointed to the National Science Board by President George W. Bush in 2004. Dr. Lanzerotti holds a Ph.D. in physics from Harvard University.

CARL A. ALEXANDER is an expert in the behavior of nuclear material at high temperatures and also in biological and chemical weapons. He is chief scientist and senior research leader at the Battelle Memorial Institute in Columbus, Ohio. Dr. Alexander worked on fuel design and behavior for the aircraft nuclear propulsion program and several space nuclear power projects, including the Viking, Voyager, and Cassini missions. He helped analyze the evolution of the Three Mile Island accident and is involved in the French Phebus fission product experiments, which are to reproduce all of the phenomena involved during a nuclear power reactor core meltdown accident. He has served as a consultant to the Nuclear Regulatory Commission and, in the 1970s, worked on the first experiments on the effects of an attack on spent fuel shipping containers using shaped charges. He currently leads research projects on agent neutralization and collateral effects for.weapons of mass destruction for the Defense Threat Reduction Agency and the Navy, and on lethality of missile defense technologies for the Missile Defense Agency. Dr. Alexander has taught materials science and engineering at the Ohio State University and has served as graduate advisor and adjunct professor at the Massachusetts Institute of Technology, University of Southampton in the United Kingdom, and the University of Maryland. He has authored over 100 peer-reviewed articles and technical reports, many of which are classified. He holds a Ph.D. in materials science from Ohio State University.

ROBERT M. BERNERO is a nuclear engineering and regulatory expert. He is now an independent consultant after retiring from the U.S. Nuclear Regulatory Commission (USNRC) in 1995. In 23 years of service for the USNRC Mr. Bemero held numerous positions in reactor licensing, fuel cycle facility licensing, engineering standards development, risk assessment research, and waste management. His final position at USNRC was as director of the Office of Nuclear Materials Safety and Safeguards. Prior to joining the USNRC he worked for the General Electric Company in nuclear technology for 13 years. He has served as a member of the Commission of Inquiry for an International 87

88 SAFETY AND SECURITY OF COMMERCIAL SPENTFUEL STORAGE Review of Swedish Nuclear Regulatory Activities, and he currently consults on nuclear safety-related matters, particularly regarding nuclear materials licensing and radioactive waste management. Mr. Bernero received his B.A. degree from St. Mary of the Lake (Illinois), a B.S. degree from the University of Illinois, and an M.S. degree from Rensselaer Polytechnic Institute.

M. QUINN BREWSTER is an expert in energetic solids and heat transfer. He is currently the Hermia G. Soo Professor of Mechanical Engineering at the University of Illinois at Urbana-Champaign. He is involved in the Academic Strategic Alliance Program, whose objective is to develop integrated software simulation capability for coupled, system simulation of solid rocket motors including internal ballistics (multi-phase, reacting flow) and structural response (propellant grain and motor case). Dr. Brewster has authored one book on thermal radiative transfer and chapters in four other books as well as several publications on combustion science. He is a fellow of the American Society of Mechanical Engineers and associate fellow of the American Institute of Aeronautics and Astronautics. Dr. Brewster holds a Ph.D.

in mechanical engineering from the University of California at Berkeley.

GREGORY R. CHOPPIN is an actinide elements and radiochemistry expert. He is currently the R.O. Lawton Distinguished Professor Emeritus of Chemistry at Florida State University.

His research interests involve the chemistry and separation of the f-elements and the physical chemistry of concentrated electrolyte solutions. During a postdoctoral period at the Lawrence Radiation Laboratory, University of Califomia, Berkeley, he participated in the discovery of mendelevium, element 101. His research and educational activities have been recognized by the American Chemical Society's Award in Nuclear Chemistry, the Southern Chemist Award of the American Chemical Society, the Manufacturing Chemist Award in Chemical Education, the Chemical Pioneer Award of the American Institute of Chemistry, a Presidential Citation Award of the American Nuclear Society, the Becquerel Medal, British Royal Society, and honorary D.Sc. degrees from Loyola University and the Chalmers University of Technology (Sweden). Dr. Choppin previously served on the NRC's Board on Chemical Sciences and Technology and Board on Radioactive Waste Management. He holds a Ph.D. in inorganic chemistry from the University of Texas, Austin.

NANCY J. COOKE is an expert in the development, application, and evaluation of methodologies to elicit and assess individual and team knowledge. She is currently a professor in the applied psychology program at Arizona State University East. She also holds a National Research Council Associateship position with Air Force Research Laboratory and serves onthe board of directors of the Cognitive Engineering Research Institute in Mesa, Arizona. Her current research areas are the following: cognitive engineering, knowledge elicitation, cognitive task analysis, team cognition, team situation awareness, mental models, expertise, and human-computer interaction. Her most recent work includes the development and validation of methods to measure shared knowledge and team situation awareness and research on the impact of cross- training, distributed mission environments, and workload on team knowledge, process, and performance. This work has been applied to team cognition in unmanned aerial vehicle and emergency operation center command-and-control. She contributed to the creation of the Cognitive Engineering Research on Team Tasks Laboratory to develop, apply, and evaluate measures of team cognition. She has authored or co-authored over 70 articles, chapters, and technical reports on measuring team cognition, knowledge elicitation, and human-computer interaction. Dr. Cooke holds a Ph.D. in cognitive psychology from New Mexico State University, Las Cruces.

BIOGRAPHICAL SKETCHES OF COMMITTEE MEMBERS 89 GORDON R. JOHNSON is an expert in penetration mechanics and computational mechanics. He is currently a senior scientist and manager of the solid mechanics group at Network Computing Services. His recent work has included the development of computational mechanics codes that include finite elements and meshless particles. He has also developed computational material models to determine the strength and failure characteristics of a variety of materials subjected to large strains, strain rates, temperatures, and pressures. His work for the U.S. Departments of Energy and Defense has included a wide range of intense impulsive loading computations for high-velocity impact and explosive detonation. He was a chief engineering fellow during his 35 years at Alliant Techsystems (formerly Honeywell). He has served as a technical advisor for university contracts with the Army Research Office, and an industry representative for its strategic planning, and was a member of the founding board of directors for the Hypervelocity Impact Society. Dr. Johnson holds a Ph.D. in structures from the University of Minnesota, Minneapolis.

ROBERT P. KENNEDY has expertise in structural dynamics and earthquake engineering.

He is currently an;independent consultant in structural mechanics and engineering. Dr.

Kennedy has worked on static and dynamic analysis and the design of special-purpose civil and mechanical-type structures, particularly for the nuclear, petroleum, and defense industries. He has designed structures to resist extreme loadings, including seismic loadings, missile impacts, extreme winds, impulsive loads, and nuclear environmental effects, and he has developed computerized structural analysis methods. He also served as a peer reviewer for an EPRI study on aircraft impacts on nuclear power plants. In 1991, he was elected to the National Academy of Engineering for developing design procedures for civil and mechanical structures to resist seismic and other extreme loading conditions. Dr.

Kennedy holds a Ph.D. in structural engineering from Stanford University.

KENNETH K. KUO is an expert in combustion, rocket propulsion, ballistics, and fluid mechanics. He is a Distinguished Professor of Mechanical Engineering at the Pennsylvania State University. He is also the leader and director of the university's High Pressure Combustion Laboratory, a laboratory with advanced instrumentation and data acquisition devices. Dr. Kuo has directed team research projects in propulsion and combustion studies for 32 years. He has edited eight books and authored one book on combustion, published over 300 technical articles, and served as principal investigator for more than 70 projects, including a Multidisciplinary University Research Initiative (MURI) grant from the U.S. Army on "Ignition and Combustion of High Energy Materials." He is now serving as principal .

investigator and co-principal investigator for two MURI programs on rocket and energetic materials. In 1991, he was elected fellow of American Institute of Aeronautics and Astronautics and has received several awards for his work on solid propellants combustion processes. Dr. Kuo holds a Ph.D. in aerospace and mechanical sciences from Princeton University.

RICHARD T. LAHEY, JR., is an expert in multiphase flow and heat transfer technology, nuclear reactor safety, and the use of advanced technology for industrial applications. He is currently the Edward E. Hood Professor of Engineering at Rensselaer Polytechnic Institute (RPI) and was previously chair of the Department of Nuclear Engineering and Science, director of the Center for Multiphase Research, and the dean of engineering at RPI.

Previously, Dr. Lahey held several technical and managerial positions with the General Electric Company, including overall responsibility for all domestic and foreign R&D programs associated with boiling water nuclear reactor thermal-hydraulic and safety technology. He has chaired several committees for the American Society of Mechanical Engineering, American Nuclear Society, American Institute for Chemical Engineering, American Society

90 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE for Engineering Education, and NASA. His current research is funded by the Department of Energy's Naval Reactors Program, the Office of Naval Research, the National Science Foundation, the New York State Energy Research and Development Authority, Oak Ridge National Laboratory, and the Defense Advanced Research Projects Agency. He currently consults on nuclear reactor safety problems and the chemical processing of non-nuclear materials and is a member of the Board of Managers of PJM Interconnection, LLC. In 1994, he was elected to the National Academy of Engineering for his contributions to the fields of multiphase flow and heat transfer and nuclear reactor safety technology. In 1995, he became a member of the Russian Academy of Sciences-Baskortostan and he is a fellow of the American Nuclear Society and of the American Society of Mechanical Engineers. He has authored or co-authored over 300 technical publications, including 10 books or handbooks and 160 journal articles. Dr. Lahey holds a Ph.D. in mechanical engineering from Stanford University.

KATHLEEN R. MEYER has expertise in health physics and radiologic risk assessment. She is a principal of Keystone Scientific, Inc., and is currently involved in risk assessments for public health and the environment from radionuclides and chemicals at several U.S.

Department of Energy sites. Other work includes an assessment of the interim radionuclide soil action levels adopted by the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency, and the Colorado Department of Health and Environment for cleanup at the Rocky Flats Environmental Technology Site. She has been a member of the National Council on Radiation Protection and Measurements Historical Dose Evaluation Committee.

Dr. Meyer has authored or co-authored several peer-reviewed articles, including papers on cancer research, historical evaluation of past radionuclide and chemical releases, and risk assessment of radionuclides and chemicals. She holds a Ph.D. in radiological health sciences from Colorado State University.

FREDRICK J. MOODY is an expert thermal hydraulics and two-phase flow in nuclear power reactors. In 1999, he retired after 41 years of service at General Electric Company and 28 years as an adjunct professor of mechanical engineering at San Jose State University. Dr.

Moody was the recipient of several prestigious career awards, including the General Electric Power Sector Award for Contributions to the State-of-the-Art for Two-Phase Flow and Reactor Accident Analysis. He has served as a consultant to the Nuclear Regulatory Commission's Advisory Committee on Reactor Safeguards, teaches thermal hydraulics for General Electric's Nuclear Energy Division, and continues to review thermal analyses for General Electric. Dr. Moody is a fellow of the American Society of Mechanical Engineers, which awarded him the George Westinghouse Gold Medal in 1980, and the Pressure Vessels and Piping Medal in 1999. He has also received prestigious career awards from General Electric and was elected to the Silicon Valley Engineering Hall of Fame. Dr. Moody was elected to the National Academy of Engineering in 2001 for pioneering and vital contributions to the safety design of boiling water reactors and for his role as educator. He has published three books and more than 50 papers. Dr. Moody holds a Ph.D in mechanical engineering from Stanford University.

TIMOTHY R. NEAL is an expert in weapons technology and explosives. He began his career at Los Alamos National Laboratory in 1967 and has led programs addressing weapon hydrodynamics, explosions inside structures and above ground, image analysis, and dynamic testing. He also has held several management positions within the Laboratory's nuclear weapons arena, including leadership of the Explosives Technology and Applications Division and of the Advanced Design and Production Technologies Initiative.

He spearheaded Los Alamos' Stockpile Stewardship and Management Programmatic

BIOGRAPHICAL SKETCHES OF COMMITTEE MEMBERS 91 Environmental Impact Statement and helped establish the U.S. Department of Energy's new Stockpile Stewardship Program. More recently, he has served as a senior technical advisor to the U.S. Department of Energy on nuclear explosive safety, and he has worked closely with the Pantex Plant for nuclear weapons productioni in Amarillo, Texas, in establishing a new formal basis for operational safety. Dr. Neal has received four DOE excellence awards, including one for hydrodynamics, and authored various technical papers and reports as well as one book on explosive phenomena. He holds a Ph.D. in physics from Carnegie-Mellon University.

LORING A. WYLLIE, JR. is an expert in structural engineering and senior principal of Degenkolb Engineers. His work has included seismic evaluations, analysis, and design of strengthening measures to improve seismic performance. He has performed seismic assessments and proposed strengthening solutions for several buildings within the U.S.

.Department of Energy weapons complex and for civilian buildings, some of which have historical significbnce. Mr. Wyllie's expertise is also recognized in several countries, including the former Soviet Union where he worked on an Exxon facility. Mr. Wyllie is a past president of the Earthquake Engineering Research Institute. His contributions to the profession of structural engineering were recognized by his election to the National Academy of Engineering in 1990 and his honorary membership in the Structural Engineers Association of Northern California. In recognition of Mr. Wyllie's expertise in concrete design and performance, the American Concrete Institute named him an honorary member in 2000.

Mr. Wyllie also was elected an honorary member of the American Society of Civil Engineers in 2001. He holds a M.S. degree from the University of California, Berkeley.

PETER D. ZIMMERMAN is an expert in nuclear physics and terrorism. He is currently the chair of science and security and director of the Centre for Science & Security Studies at King's College in London. He previously served as the chief scientist of the Senate Foreign Relations Committee, where his responsibilities included nuclear testing, nuclear arms control, cooperative threat reduction, and bioterrorism. Previously, he served as science advisor for arms control in the U.S. State Department, where he provided advice directly to Assistant Secretary for Arms Control and the Undersecretary for Arms Control and International Security. His responsibilities included technical aspects of the Comprehensive Test Ban Treaty, biological arms control, missile defense, and strategic arms control. Dr.

Zimmerman spent many years in academia as professor of physics at Louisiana State University. He is the author of more than 100 articles on basic physics as well as arms control and national security. His most recent publication is the monograph "Dirty Bombs:

The Threat Revisited," which was published by the National Defense University in the Defense Horizons series. Dr. Zimmerman holds a Ph.D. in experimental nuclear and elementary particle physics from Stanford University and a Fil. Lic. degree from the University of Lund, Sweden. He is a fellow of the American Physical Society and a member of its governing council. He is a recipient of the 2004 Joseph A. Burton/Forum award for physics in the public interest.

C TOUR OF SELECTED SPENT FUEL STORAGE-RELATED INSTALLATIONS IN GERMANY On April 25-28, 2004, six committee members visited spent fuel storage-related installations in Germany. The following is a summary of some of the pertinent information obtained from that trip.

Several organizations and individuals worked with committee staff to make this trip possible. The committee would especially like to acknowledge Alfons Lfhrmann and William McConaghy of GNB/GNSI (Gesellschaft fOr Nuklear-Beh~lter, mbH/General Nuclear Systems, Inc.), who organized site visits; Klaus Janberg (STP engineering); Michael Sailer, chairman of RSK (Reaktorsicherheitskommission-reactor safety commission); Holger Broeskamp manager of GNS (Geselichaft fOr Nuklear-Service, mbH-Germany's nuclear industry consortium) and his staff; Wolfgang Sowa, managing director of GNB (Gesellschaft fOr Nuklear-Beh~lter, mbH) and his staff; Florentin Lange of GRS (Gesellschaft fOr Anlagen-und Reaktorsicherheit, mbH); and Hubertus FlOgge, vice-president of the RWE Power AG plants in Lingen and his staff, who allowed the committee to visit the reactor building and the site's spent fuel storage facility.

CA GERMAN COMMERCIAL NUCLEAR POWER PLANTS Germany currently has 18 operating commercial nuclear power reactors at 12 sites.

Approximately one-third of the reactors are boiling water reactors (BWRs) and two-thirds are pressurized water reactors (PWRs).

The design for PWR plants is illustrated schematically in FIGURE C.1. It consists of a dome-shaped reactor building constructed of reinforced concrete and a spherical inner containment structure constructed of steel. The reactor core, spent fuel pool, and steam generators are located within the inner containment. The emergency core-cooling systems are located outside the inner containment but within the reactor building.

The German BWR reactor building design is generally similar to a PWR. However, the spent fuel pool is outside the inner containment structure but within the reactor building.

The reactor building is also a different shape (rectangular or cylindrical).

There are three generations of commercial nuclear power plants in Germany, each having increasingly thick walls:

• First-generation plants have reactor building walls that are less than 1 meter thick. There are four plants of this type.

• Second-generation plants have reactor building walls that are slightly more than 1 meter thick. There are five plants of this type.

• Third-generation plants have reactor building walls that are about 2 meters thick.

There are nine plants of this type.1 1 The committee subgroup visited one of these plants (the Lingen power plant) during its tour.

92

TOUR OF GERMAN SPENT FUEL STORAGE INSTALLATIONS 93 Some first- and second-generation plants have independent emergency systems in a bunkered building that contains some safety trains and a control room. These systems are capable of delivering water to the reactor after an accident or attack if the pipe systems within the reactor building survive.

Second- and third-generation plants were designed to withstand the crash of military fighter jets. Second-generation plants were designed to withstand the crash of a Starfighter jet at the typical landing speed. Third-generation plants were designed to withstand the crash of a Phantom jet at the typical cruising speed. This is considered to be part of the "design basis threat" for nuclear power plants in Germany. This information on the design basis threat has been made available to the public by the German government.

Siemens Pressurized Water Reactor,.

I Reactor pressure vessel and core suppbrt stru6tur 2 Steam generators 3 Reactor coolant pumps Reactor coolant pipings S54 Presurizer 6 Steel containment (thickness=38 mm) 7 Nucler systems buildings (thickness=2.2 m) 8 Reactor building annulus FIGURE C.1 Schematic illustration of the Lingen PWR power plant, a third-generation power plant design. SOURCE: RWE Power.

94 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Plant operators must show that of the four safety trains (each train contains 50 percent of the safety system) at the plant, at least two will survive such a crash. The crash parameters (e.g., aircraft type, speed, and angle) have been established by RSK. The crash parameters have been published and the public knows about them. Each plant must perform an independent analysis of each reactor building. Sometimes two separate analyses have to be provided for the same site if there are two or more reactors with different designs.

In 1998, the German government decided to phase out nuclear energy. Commercial nuclear plants will be allowed to generate an agreed-to amount of electricity before shutdown. Currently, the Lingen and the Neckarwestheim-2 plants have the highest remaining electricity production allowance and will be shut down in 2021 or 2022, should no revision of this political decision be implemented.

C.2 SPENT FUEL STORAGE Until recently, all spent fuel at German plants was stored in the reactor pools until it could be sent to Sellafield (U.K.) or La Hague (France) for reprocessing. In the 1980s, plants began to re-rack their spent fuel pools to increase storage capacities (the older German nuclear plants were designed to contain one full reactor core plus one third of a core). Regulators became concerned that the emergency cooling systems were not sufficient to handle the increased heat loads in spent fuel pools from this re-racking. Some plants added additional cooling circuits to address this concern. Only one power plant (an older plant at Obrigheim) has wet interim pool storage in a bunkered building.

A discussion of alternative spent fuel storage options began in 1979. A reprocessing plant had been proposed at Gorleben that would have had several thousand metric tons of pool storage. The German government concluded that while there were no major technical issues for reprocessing, wet fuel storage was a potential problem because cooling systems could be disrupted in a war. GNS decided to shift from wet to dry storage for centralized storage facilities.

There are two centralized storage facilities in Germany: Gorleben and Ahaus.

Gorleben is designed to store vitrified high-level waste from spent fuel reprocessing and spent fuel from commercial power reactors. Ahaus is designed to store spent fuel from test reactors and other special types of fuel. Ahaus currently stores 305 casks of reactor fuel from the decommissioned Thorium High Temperature Reactor, three casks of PWR spent fuel from the Neckarwestheim site, and three casks of BWR spent fuel from the Gundremmingen site. The latter shipment produced large public demonstrations and required the deployment of 35,000 police officers to maintain security.

At the end of 2001, the German utility companies and the German federal government agreed to avoid all transport of spent fuel in Germany because of intense public opposition. The German government recently passed a law making it illegal to transport spent nuclear fuel to reprocessing plants in France and the United Kingdom after June 30, 2005. However, there is no legal restriction concerning the transport of spent fuel from power reactors to other destinations (e.g., to dry storage facilities). The government and power plant operators have negotiated an agreement to develop dry cask storage facilities at each of the 12 nuclear power plant sites to avoid the need for offsite spent fuel transport.

TOUR OF GERMAN SPENT FUEL STORAGE INSTALLATIONS 95 These dry cask storage facilities are to be constructed by 2006. They are licensed to store fuel for 40 years.

There are three dry cask storage facility designs in Germany:

1. WTI design: The walls and roof are constructed of 80 and 50 centimeters, respectively, of reinforced concrete.

2. STEAG design: The walls and roof are constructed of 1.2 and 1.3 meters, respectively, of reinforced concrete. This design is used at the Lingen Nuclear Power Plant dry storage facility visited bythe committee (FIGURE C.2).

3. GNK design: This is a tunnel design and is under construction at the Neckarwestheim nuclear power plant.

The use of reinforced concrete in these facilities was originally intended for radiation protection and structural support, not for terrorist attacks.

In 1999, RSK issued guidelines for dry storage, which were released in 2001 (RSK, 2001). Licensing a dry storage facility in Germany requires several safety demonstrations and analyses. As part of the licensing procedures for a storage facility, the license applicant must do independent calculations that demonstrate how the building features meet the safety standards and the design basis threat. This threat includes an armed group of intruders and the impact of a Phantom 2 military jet. It also includes a shaped charge. The scenario of a deliberate crash of a large civilian airplane has been considered and analyzed as part of the recent licensing of onsite dry storage facilities but is not established as part of the design basis threat. There are public hearings during which the license applicant explains the safety features of the storage facility. The public is aware of the design basis threat, and it is provided with the results of the analysis but not with the details.

~ I FIGURE C.2 Dry cask spent fuel storage building at the Lingen Nuclear Power Plant.

SOURCE: RWE Power.

96 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE There are six temporary (i.e., five- to seven-year) storage facilities in use at reactor sites until these dry cask storage facilities become available. The casks in these temporary storage facilities are stored horizontally and are protected by concrete "garages" designed to withstand the impact of a Phantom military jet.

Spent commercial fuel is stored in CASTOR casks (FIGURE C.3) that were originally designed and developed by the German utility-owned company GNB.2 These casks can store either PWR or BWR spent fuel assemblies. The design consists of a ductile cast iron cylindrical cask body with integral circumferential fins machined into the outer surface to maximize heat transfer; inside, the spent fuel assemblies are inserted in a borated stainless steel basket. The cask has a double-lid system that is protected by a third steel plate. The cask complies with the international regulations of the International Atomic Energy Agency (IAEA) as a type B(U) package.

Spent fuel is typically cooled for five years in a pool before it is put in dry cask storage; some other custom-made cask designs can hold fuel that has been cooled for shorter (minimum two years) or longer times depending on the fuel characteristics and fuel bum-up. Current fuel bum-ups in Germany (52 to 55 gigawatt-days per metric ton) are similar to those in the United States.

FIGURE C.3 Typical features of a CASTOR cask used at the Lingen Nuclear Power Plant.

SOURCE: RWE Power AG Lingen Nuclear Power Plant.

2 Gesellschaft fOr Nuklear-Beh~lter, mbH.

TOUR OF.GERMAN SPENT FUEL STORAGE INSTALLATIONS 97 C.3 RESPONSE TO THE SEPTEMBER 11, 2001, TERRORIST ATTACKS IN THE UNITED STATES The September 11, 2001, terrorist attacks on the United States caused the German government to reassess the security of its nuclear power plants and spent fuel storage facilities. RSK held meetings starting in October 2001 to discuss the implications of the September 11 attacks for German commercial nuclear power plants. It issued a short statement recommending that an analysis be carried out on each plant to assess its vulnerability to September 11-type attacks. These analyses have not yet been undertaken.

Plant operators assert that terrorist attacks are a general risk of society and should be treated like attacks on other infrastructure (e.g., chemical facilities). The Lnder (state) governments, which are responsible for licensing commercial power plants in Germany, do not require these analyses. RSK recommended that the federal govemment develop a checklist for such an analysis, but this also has not been done.

A general "inalysis of the impact of the different civilian aircraft on commercial nuclear plants was requested by BMU 3 and has been carried out by GRS. 4 The result of the discussions between RSK and BMU on the basis of this report was that plant specific sensitivity analyses are needed. GRS was also involved in the framing of the recent German licensing process in the analysis of the consequences of civilian aircraft attacks on STEAG-and WTI-design spent fuel storage facilities using three sizes of aircraft (ranging from Airbus A320- to Boeing 747-size aircraft).

C.4 TESTS ON GERMAN CASKS The casks that are used in German dry cask storage facilities have been subjected to several tests that simulate accidents and terrorist attacks. The following types of tests were performed on these casks or cask materials.

Airplane crash test simulations with military aircraft (Phantom type) are part of the licensing requirements for both casks and storage facilities. Between 1970 and 1980 a number of tests on storage casks were carried out at the Meppen military facility in Germany. A one-third scale model of a GNB cask was used to simulate the impact of a turbine shaft of a military aircraft using a hollow-tube projectile. Two different impact orientations were used: perpendicular to upright cask body (lateral impact) and perpendicular to center of lid system. The projectile completely disintegrated in the test, but the cask sustained only minor damage.

The jet aircraft tests were carded out because of safety concems, but after September 11, 2001, intentional crashes of aircraft also were considered. Investigations by BAM (Bundesanstalt fOr Materialforschung und -prnfung ) and GRS concluded that CASTOR-type casks would maintain their integrity when intentionally hit by a commercial aircraft.

3 Bundesministerium for Umwelt, Naturschutz and Reaktorsicherheit (Federal Ministry for Environment, Nature Protection, and Nuclear Safety and Security).

4Gesellschaft fOr Anlagen- und Reaktorsicherheit (GRS), mbH (Company for Installation and Reactor Safety). GRS is Germany's main research institution on nuclear safety. It is an independent, nonprofit organization, founded in 1977, and has about 450 employees. GRS funds its work through research contracts. Some have compared GRS to Sandia National Laboratories in the United States.

98 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Other types of terrorist attacks have been a long-standing concern to the German government because of terrorism activities in Europe in the 1970s and 1980s. A series of tests simulating terrorist attacks on casks were done in Germany, France, the United States (for the German government), and Switzerland (for the Swiss government). Additional tests may have been done that are not publicly acknowledged.

In 1979-1980 at the German Army facility in Meppen, a "hollow charge" (i.e., shaped charge) weapon was fired at a ductile cast iron plate and fuel assembly dummy to simulate a CASTOR cask. The cask plate was perforated but release fractions from the fuel assembly were not examined. From this experiment, the German government concluded that the wall thickness of the cask should not be less than 300 millimeters.

Other tests were carried out at the Centre d'Etude de Gramat in France in 1992 on behalf the Germany Federal Ministry of Environment, Nature Protection and Nuclear of Safety (BMU) (Lange et al., 1994). These tests involved shaped charges directed at a CASTOR cask (type CASTOR Ila, the cask was one third of the regular length) filled with nine fuel element dummies with depleted uranium. The fuel rods were pressurized to 40 bars to simulate fuel bum-up, but the cask interior was at atmospheric pressure or at reduced pressure of 0.8 bar. The shaped charge perforated the cask and penetrated fuel elements. This damaged the fuel and resulted in the release of fuel particles from the cask.

These particles were collected, and their particle size distribution was measured.

About I gram of uranium was released in particles of less than 12.5-microns aerodynamic diameter, and 2.6 grams of uranium were released in particles with a size range between 12.5 and 100 microns. Ifthe pressure inside the cask was reduced to 0.8 bar (to simulate the conditions during interim storage of spent fuel in Germany), the releases were reduced by two-thirds: 0.4 gram for particle sizes less than 12.5 microns and about 0.3 gram for particles between 12.5 and 100 microns.

In 1998, a demonstration was carried out at the Aberdeen Proving Ground in the United States using an anti-tank weapon on a CASTOR cask. The purpose of this demonstration was to show that a concrete jacket on the exterior of the cask could prevent perforation. The weapon was first fired at the cask without the jacket. It perforated the front wall of the cask. The concrete jacket was effective in preventing perforation of the cask.

Committee members saw a specimen of this cask at the GNB workshop (see FIGURE C.4).

Also in 1999, explosion of a liquid gas tank next to a cask was performed by the German BAM (Federal Office of Material Research and Testing) to study the effect of accidents involving fire or explosions in the vicinity of the cask during transportation or storage. The gas tank and the CASTOR cask were initially about 8 feet (2.5 meters) apart.

Explosion of the tank generated a fire ball 330 to 500 feet (100 to 150 meters) in diameter.

The explosion projected the cask 23 feet (7 meters) away and tilted it by 180 degrees, causing it to hit the ground on the lid side. Examination after the explosion showed no change in the containment properties of the lid system.

TOUR OF GERMAN SPENT FUEL STORAGE INSTALLATIONS 99 FIGURE C.4 Section of a CASTOR cask showing the perforation made by a shaped charge at the Aberdeen Proving Ground. SOURCE: Courtesy of GNB/GNSI.

REFERENCE Lange, F., G. Pretzsch, J. Dbhler, E. Hbrmann, H. Busch, and W. Koch. 1994. Experimental Determination of U0 2-Release from a Spent Fuel Transport Cask after Shaped Charge Attack. 35th INMM Annual Meeting Proceedings (Naples, Florida). Vol. 23, -

pp. 408-413.

RSK (Reaktorsicherheitskommission). 2001. Safety-Related Guidelines for the Dry Interim Storage of Spent Fuel Elements in Storage Casks. Recommendation of the Commission on Reactor Safety. April 5. Available at http://www.rskonline.

de/Download/Leitlinien/English/RSK-GUIDELINES-DRY-INTERIM-STORAGE.pdf.

D HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL POWER REACTOR FUEL OPERATIONS There are 103 commercial power reactors operating in the United States at this time.

Almost all of them are operating with spent fuel pools that are too small to accommodate cumulative spent fuel discharges. This short appendix was prepared to provide a historical background for power reactor fuel operations and pool and dry-cask storage of spent fuel.

D.A DESIGN FOR A CLOSED FUEL CYCLE The first large generation of commercial reactors in the United States were almost all light water reactors (LWRs), that is, nuclear reactors that use ordinary water to cool the core and to moderate the neutrons emitted by fission. The hydrogen atoms in the water coolant moderate, or slow down the fission-emitted neutrons to an energy level that is more likely to cause fission when the neutron strikes a fissile atom. These reactors were designed, developed, and licensed in the 1960s and 1970s, although many were not completed until the 1980s. Their design power output increased rapidly, as it did for non-nuclear power plants, in order to achieve economies of scale. Thus, the earlier plants in this generation were designed to produce 500-900 megawatts of electrical power (MWe) while later units increased to 1000-1200 MWe. The number of LWRs built and ordered by the U.S. industry began to approach 200. All of these plants were being designed for a closed fuel cycle, that is, for the uranium oxide fuel, enriched to 2-5 percent uranium-235, to be loaded and "burned" to a level of 20-30 gigawatt-days per metric ton of uranium (GWd/MTU), then reprocessed in commercial plants to separate the still usable fissionable, or fissile, materials in the spent fuel from the radioactive waste. The reprocessing plants would recover the fissile plutonium-239 formed from uranium-238 during reactor operations and residual fissile uranium-235 for use as fuel in LWRs and later in breeder reactors (USNRC, 1976).

By the mid-1 970s commercial reprocessing plants were built, under construction, or planned in New York, Illinois, South Carolina, and Tennessee, with a combined projected capacity to reprocess more than 6000 MTU of spent fuel per year. For comparison, a large LWR discharges about 20 MTU of spent fuel at a refueling. By this time the price of fresh uranium was dropping and the cost of fuel reprocessing made it difficult for recycle fuel to compete with fresh fuel. Also, there was controversy about the risk of fissile material diversion if recycled plutonium was moved in commercial traffic. Both existing fuel reprocessing plants withdrew from licensing for technical reasons and then, on April 7, 1977, President Carter issued a policy statement that "we will defer indefinitely the commercial reprocessing and recycling of the plutonium produced in the U.S. nuclear power programs."

The statement went on to say: "The plant at Barnwell, South Carolina, will receive neither federal encouragement nor funding for its completion as a reprocessing facility." After consultation with the White House, the U.S. Nuclear Regulatory Commission (USNRC) terminated its Final Generic Environmental Statement on the Use of Recycled Plutonium in Mixed Oxide Fuel in Light-Water Cooled Reactors (GESMO) proceedings.

Thus, the U.S. nuclear industry was immediately changed from a closed fuel cycle, with recycle, to an open or once-through fuel cycle with the fuel loaded into the reactor in 100

HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL OPERATIONS 101 several consecutive locations to obtain maximum economic use of the fuel before it was finally removed as waste. The USNRC changed the legal definition of high-level radioactive waste to include the high-level waste from both nuclear fuel reprocessing and spent nuclear fuel.

For this study, the significance of this closed fuel cycle design is that this entire generation of more than 100 reactors was designed with small spent fuel pools, relying on prompt shipment away from the reactor to the reprocessing plant to make room for later discharges of spent fuel. Early spent fuel shipping casks were being designed with active cooling systems to support shipment of fuel less than a year out of the reactor to a reprocessing plant. BOX D.1 discusses the spent nuclear fuel at reprocessing plants.

Supplementary wet and dry storage systems had to be developed to receive the older spent fuel to make room for fresh spent fuel from the reactor. Many plants had to remove and modify the storage racks in their spent fuel pools to accommodate more spent fuel in the pool itself until licensed supplementary systems were available.

D.2 RETRENCHMENT OF U.S. REACTOR PLANS As noted in Section D.1, in the 1970s the United States was building reactors at a high rate. Then, in the late 1970s, three factors produced a retrenchment in power reactor plans: rising interest rates, reversal of the U.S. fuel reprocessing policy, and the Three Mile Island-2 accident.

D.2.1 Effect of Interest Rates Commercial power reactors have characteristically high initial capital costs. The regulated public utilities have had to raise the capital with various debt instruments; to build, license, and operate the finished plant for a time before it can be declared commercial; and to change the electricity rates charged consumers to retire the debt on the capital cost. The soaring interest rates in the United States during the late 1970s drove the costs of new nuclear plants that were under construction to extreme heights. This, combined with slackening demand for electricity, led to the cancellation of many plants, some even in advanced stages of construction.

D.2.2 Effect of Reversal of U.S. Fuel Reprocessing Policy President Carter enunciated a change in U.S. policy for reprocessing of spent nuclear fuel in early 1977. Those reactors then operating and those under construction had to begin modifying their reactor fuel cycle design to go from the closed (reprocessing) cycle to a "once-through" fuel cycle. This induced the designers to go to higher levels of uranium-235 enrichment in the new fuel, but still within the 5 percent licensing limit. It also induced the designers to revise the core loading and operating plans in order to burn or use the fissile content of the fuel to the greatest extent economically possible since the fissile residue could not be retrieved by reprocessing. As a result, spent fuel bumup levels rose to levels that are now almost double the 20-30 GWd/MTU characteristic of the original closed fuel cycle. This results in an increase in the decay-heat power of the spent fuel assembly by the time it is put into the spent fuel pool.

102 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE BOX D.1 ,Spent Fuel ,at Nuclear; Fuel Reprocessing Plants..* *,<,::.,**-:**;.:s***.,*>*

until the mid-1I970s the commercial nuclear industry wasexpected to operate',

'everal;Up several nuclear.fuel -reprocessing ,plants to recoverýfissie plutonium from virtually all tofhe fel frmU.Sreactorsh eentplantswoulduse reprocessin metods developdb.teoi 'Energ Corisih ACTeTeo dpJ1tum"~

was6t& be.*used "as mfixed oxide .fuel i(uO2and UO_)and a I breeder, reactors.Each ýeprocessing plant had oneo otorge6todlsto re fuleind cth~erfelreator t reprocessed. No rwas erm orageof.the spent fuel fromi.

car t w planned'Onlyto mmerclalreprocessing stes nhave eceive spent fiueIWestVall~ey',New Yo6rk,_~h .Morris,, llinois: (,.

_.":'The first commercial reprocessing plant began operations by the Nuclear Fuel ,.

Services Companiyon a siteui West ~ork; ownedbyAhe ýStatedof NewYork. ý aailey,.New TheAStateof NewYorklicensed -alow-evel r gite adjacent to the 4' rplant-The West Valleyaplanthad ,aieprocesslngcapac tYof aboutl.metricton of,uranlum:W(MTU) rper. day.:lt opherted atredued capacity bmuch bhecause therewas notyet 5 corm'mercilaspentfuel to reprocess..ln efact; about half oftes pentfuelreprocessed there,-,

wa 1rh he last' intenres of ~lniuiiýn aduri~ntrgctorsth e. NReactor,-atiAE:

site anfh hprovlded sfuel spent was the Westi:Valeya ke t workiging hn&*eearidays *when 1litle :mmercalspnit fuel-was, avaiable ;,TheeWes Vleyi plant, sspendedlnoaeris in *!972 odet'xpa itd actytoabut 3 MTUper.dayi-Th6ew* and athre- icensinggeffort wenth.on un'ti[ 1976 when ompabthe; neithe .t appllcao6.for,6the new Icenseianete ed reocess gope g-operatons. The U.*S4-;n.

~epartment of*Energyi(D.OE) :took ov'ethetask ofhigh-:level radoactive wasteqretievalrand,.

ecommlss~nlngunder.dhe West mnstrationProject!At ofI1980 137* MTU "alley, Iout of1commerlal spent fuel remaining ciqnthecoohngpool was-returmed to its owners (USNRC 1987)In203thast"bf his`spbt fu'.6 ý_-abo13t 25'TU ito d ishihingcasks wVa's shippd Ito thebDOE-ldah6 NationaltLi66.wh' itA renmainsi 'd zt~get

'--hne enieral Electric Company Uilt a rnuclearuel ;reprocessing plantat; Moms"e" IlinOi*snear the*Dresdeni Nuclear owerStatio~njThe plant was expected to ýreprocess,3 MTU .per~day.!When the.G.E.,Momrs, plahntwasi it sflinai testing in l 975,ahe~company 5>*3/4:

dletermined that' its*performance would ?not belaceptablewthut extensve riodihficatons **:,

The.recquest for a r ocessing plant oerating ii cense Was Withdrawnaand the pant was mli bd'yrg ~lestoage'6lystem !piAt nulesibew- gdliot o a Utondehcl ,

moretsectfto reprlG6E '?sAfr hs'rece ved an toeOOTUf spent f6el ;fo`r-vanous .owners.;.+÷*  :.s;-h*4;,g,:

Power reactors are refueled, and spent fuel is discharged to the storage pool, every one to two years. The decay-heat power of recently discharged spent fuel dominates the heat load of all the spent fuel in the pool, both freshly discharged and old, since the decay heat from a spent fuel assembly decreases by one to two orders of magnitude in the first year after it is removed from the reactor. Increasing the capacity of the spent fuel pool by re-racking, that is, modifying the storage racks to provide for closer spacing of the fuel assemblies,' allows older fuel to be accumulated in the pool rather than being removed for

'The capacity of spent fuel pools has typically been increased by replacing the original storage racks with racks that hold the spent fuel assemblies closer together. The fuel assembly channels in these

HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL OPERATIONS 103 shipment or dry storage. Re-racking can make it more difficult to cool the freshly discharged fuel if there is catastrophic loss of the fuel pool water.

D.2.3 Effect of the Three Mile Island Accident The final factor driving the retrenchment of the nuclear power industry was the Three Mile Island-2 (TMI-2) accident that occurred on March 28, 1979, in Pennsylvania (Walker, 2004). In that accident a small failure in the reactor coolant system was compounded by operator errors to result in catastrophic damage; a partial core melt occurred. The inability of the operators to understand and control the events, and the confusion among the state, the USNRC, and other responsible agencies about public protection had a devastating effect on public trust in the safety of nuclear power. The USNRC escalated safety requirements after the TMI-2 accident. These new requirements substantially modified the operation of licensed plants, delayed completion of new plants, and further increased their construction costs. The accident also restilted in the retrenchment of nuclear power in the 1980s and led to the cancellation of many plants, decommissioning of some plants, and the sale of some plants to other owners. The fleet of operating U.S. reactors was reduced to the presently operating 103 described here.

D.3 COMMERCIAL POWER REACTORS CURRENTLY OPERATING IN THE UNITED STATES All of the commercial power reactors operating in the United States are light wate'r reactors. BOX D.2 describes the LWRs that are currently operating in the United States.

D.3.1 Pressurized Water Reactors About two-thirds of the U.S. reactors are pressurized-water reactors (PWRs), dual-cycle plants in which the primary cooling water is kept under a pressure of about 2000 pounds per square inch absolute (psia) as it circulates to remove fission and decay heat from the reactor fuel in the core and carry that energy to the steam generators, to generate steam in the lower-pressure secondary loop. The reactor, primary loop piping, and steam generators are all located in the containment structure; the steam lines penetrate the containment carrying the steam to the turbine to generate electrical power.

About one-third of the U.S. reactors are boiling-water reactors (BWRs), single-cycle plants in which the primary coolant of the reactor core is operated at about 1000 psia as it recirculates within the reactor core. The fission and decay heat generated in the core cause a substantial amount of the reactor coolant water to boil into steam that passes out directly from the reactor pressure vessel to the turbine-generator system. Plant differences stem initially from the different designs of the nuclear steam system supplier, the different designs of the architect-engineers that built the plants, and the owners that often specified additional modifications.

replacement racks typically have solid metal walls with neutron-absorbing material for nuclear safety reasons. This configuration inhibits water or air circulation more than the earlier configuration.

104 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE The PWRS operating in the United States were designed by three different nuclear steam system suppliers; Westinghouse Electric, Combustion Engineering, and Babcock &

Wilcox. Most PWRs have what are called large dry containments, that is, containment structures of about 2 million cubic feet volume that can absorb the rapid release of steam and hot water from a postulated rupture of the primary coolant system without exceeding an internal pressure of about 4 atmospheres. FIGURE D.1 illustrates a PWR in a large dry containment. Some PWR containments are essentially as large but use ventilation fans to maintain the initial containment pressure mildly sub-atmospheric to provide an additional pressure margin. Finally, one set of nine Westinghouse PWRs uses ice-condenser containment structures, in which the containment has about the same pressure capability but is smaller, relying on massive baskets of ice maintained in the containment to condense steam releases and mitigate the pressure surge.

D.3.2 Boiling Water Reactors The BWRs in operation today were designed by the General Electric Company. They all use pressure suppression containments, two-chamber systems with the reactor located in a dry well that is connected to a wet well containing a large pool of water.

In the event of a rupture of the reactor system in the dry well, the steam and hot water released are channeled into the water in the wet well, condensing and cooling the steam to mitigate the pressure surge. BOX D.2 lists the three successive generations of BWR containment design, and the number of each still operating. FIGURE D.2 illustrates three types of BWR containments: Mark I, Mark II, and Mark III. The Mark I containment is the most common type with 22 in operation. The reactor pressure vessel, containing the reactor core is located in a dry well of the containment in the shape of an inverted incandescent light bulb.

HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL OPERATIONS 105 Fuel-handling Containment building building Twbogenerator building FIGURE D.1 A PWR in a large dry containment. SOURCE: Modified from Duderstadt and Hamilton (1976, Figure 3-4).

The dry well is connected by large ducts to the wet well, a large toroidal (i.e.,

doughnut-shaped) part of the containment that is partially filled with water. Gas and steam releases from an accident in the dry well would be passed through the connecting ducts into the water in the wet well, cooling the gas and condensing the steam to mitigate the accident pressure rise in the containment. The containment building Mark II BWR is similar to the Mark I except that in the Mark II containment the conical dry well is directly above the cylindrical wet well. Nine Mark II reactors are still operating in the United States. In the Mark III, the dry well around the reactor vessel is vented to the top of a cylindrical wet well that surrounds it.

Four Mark III BWRs are currently operating. The entire dry well-wet well system is contained within a large steel containment shell and a concrete shield building.

D.3.3 Reactor Fuel and Reactor Control TABLE D.1 presents the range of dimensions and weights for a wide variety of the LWR fuel assemblies used in the operating reactors. The spent fuel pools and the dry storage systems used at a reactor must be tailored to the specific fuel design for that reactor.

106 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 1 - PRIMARY CONTAINMENT 2 - DRYWELL 3 - WE3"WELL 4 , SUPPRESSION POOL 13 2

V2 "e *- = _ _

MARK I MARK If MARK OU FIGURE D.2 Three types of BWR containment system: Mark I, Mark II, and Mark Ill. SOURCE: Modified from Lahey and Moody (1993, Figure 1-9).

The fission process is controlled by the reactor operators through the use of neutron-absorbing materials. The primary control is an array of control rods or blades that can be withdrawn from the core to the degree needed. In the PWRs, the control rods are moved within selected empty tubes within the assembly. In the BWRs, cruciform (cross-shaped) control blades are moved across the faces of the fuel assembly, typically narrower than those in a PWR fuel assembly. Reactor fuel designers also use burnable poisons within the fuel assembly to control the fission process. These poisons are placed in appropriate amounts within the fuel assembly so that they bum away, making the fuel assembly more reactive, as the continued fission process is making it less reactive. PWRs also use neutron control by dissolving neutron-absorbing sodium borate in the reactor coolant, gradually lowering the concentration from the peak after refueling to the minimum before the next refueling.

REFERENCES American Nuclear Society. 1988. Design Criteria for an lindependent Spent Fuel Storage Installation (Water Pool Type): An American National Standard. ANSI/ANS-57.7-1988. American Nuclear Society. LaGrange Park, Illinois.

Duderstadt, J. J. and L. J. Hamilton. 1976. Nuclear Reactor Analysis. John Wiley & Sons.

New York.

Lahey, R. T. and F. J. Moody. 1997. The Thermal Hydraulics of a Boiling Water Nuclear Reactor. Second Edition. American Nuclear Society. La Grange Park, Illinois.

HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL OPERATIONS 107 USNRC (U.S. Nuclear Regulatory Commission). 1976. Final Generic Environmental Statement on the Use of Recycled Plutonium in Mixed Oxide Fuel in Light-Water Cooled Reactors (GESMO). NUREG-0002. Washington, DC.

USNRC. 1987. Case Histories of West Valley Spent Fuel Shipments. NUREG/CR-4847.

January. Washington, D.C.

Walker, J. S. 2004. Three Mile Island: A Nuclear Crisis in Historical Perspective. University of California Press. Berkeley, California.

TABLE D.1 Range of Dimensions and Weights for Light Water Reactor Fuel Assemblies Used in Operating Reactors in the United States.

Physical Characteristics of Typical LWR Fuel Assemblies Reactor Type BWR BWR PWR PWR PWRFE PWR PWR PWR PWR PWR PWR PWR Fuel Designer GE GE B&W R&W GE GE W W W W W W Fuel Rod Array 7x7 SIB iSXlS 17x17 14x14 16x16 14x14 14x14 Six15 2Sx15 17x17 17x47 Active Fuel Length (in.) 14*4 144 144 143 137 150 120 144 121 144 144 168 Nominal Envelope (in.P . 5.438 5.47 8.536 8.536 8.25 8.25 7.763 7.763 8.449 8,426 8.426 8.426 Fuel Assembly Length 6in.) 176 176 166 166 157 177 137 161 137 160 160 -

Weight (lbs.) 600 600 1.516 1.502 581 kg - 801 kg 573 kg 594 kg 654 kg 665 kg -

Fuel Rod Number 49 63 208 264 164 224.236 180 179 204 204 264 264 Length 6r.1 163 - 153 - 147 161 127 152 127 152 152 -

Pitch. Square (in.) 0.738 0.640 0.568 0.501 0.580 0.506 0.556 01556 0.563 0.563 0.496 0.496 O.D. (in.) 0.570 0.493 0.430 0.379 0.440 0.382 0.422 0.422 0.422 0.422 0.374 0.360 Clad Thickness Imili.) 35.5 34 26.5 23.5 " 26 25 16.5 24.3 16.5 24.3 22.5 22.5 Clad Material Zr2 Zr2 Zr4 Zr4 Zr4 Zr4 sat Zr4 s3t Zr4 Zr4 Zr,4 Pellet O.D. (in.) 0.488 0.416 0.370 0.3232 0.3795 0.325 0.3835. 0.3659 0.3835 0.3659 0.3225 0.3088 Pellet Length fin.) - - - 0.375 0.650 0.90 0.600 0.600 0.600 0.600 0.530 0.530 Gap. Radial Imils.) 5.5 4.5 3.5 3.1 4,3 .3.5 2.8 3.8- 2.8 3.8 3.3 3.3 Density ISTD) .- - 92.5-95.0 93.5-95.0 93.0-95.0 "94.75 93.0.94.0 92.0 93.0.94.0 92.0 95.0 95.0 Poison Gd.O, Gd.O. None None B.C/AI,O.

• B.C/AI, - - - - - -

Nonfueled Rods Number 0 1 *17 25 6 6 16 17 21 21 25 25 Material - Zr2 Zr4 Zr4 Zr4 Zr4 304 sst Zr4 304 sst Zr4 Zr4 Zr4 Spacer Grids Number 7 7 8 8 8 12 .. . . .

Material Inconel X Inconel X n Inlonel 718 Zr 4 1onel1718 Zr 4 . . . . . .

SOURCE: American Nuclear Society (1988).

HISTORICAL DEVELOPMENT OF CURRENT COMMERCIAL OPERATIONS 107 USNRC (U.S. Nuclear Regulatory Commission). 1976. Final Generic Environmental Statement on the Use of Recycled Plutonium in Mixed Oxide Fuel in Light-Water Cooled Reactors (GESMO). NUREG-0002. Washington, DC.

USNRC. 1987. Case Histories of West Valley Spent Fuel Shipments. NUREG/CR-4847.

January. Washington, D.C.

Walker, J. S. 2004. Three Mile Island: A Nuclear.Crisis in Historical Perspective. University of California Press. Berkeley, California.

TABLE D.1 Range of Dimensions and Weights for Light Water Reactor Fuel Assemblies Used in Operating Reactors in the United States.

Physical Characteristics of Typl6a1 LWR Fuel Assemblies Reactor Type BWR BWR PWR PWR - PWR ,WR PWR PWR PWR PWR PWR PWR Fuel Designer GE GE B&W B&W GE G W W W w w W Fuel Rod Array 7x7 Sx8 SlSx5 17x17 14x14 -1fx16" 14x14 14x14 1SxlS 17x17 17x17 144 Active Fuel Length (in.) 14.4 144 144 143 137 150 120 144 121 168 Nominal Envelope fin.12 5.438 5.47 8.536 8.536 8.25 8.25 7.763 7.763 8.449 8.426 8.426 8.426 Fuel Assembly Length (n. 176 176 168 16 157 177 137 161 137 160 160 Weight (lbs'.) 600 600 1.516 1,502 581 kg - 501 kg 573 kg 594 kg 654 kg 665 kg Fuel Rod Number 49 63 208 264 164 224.236 180 179 204 204 264 264 Length (in.) 163 153 - 147 161 127 152 127 152 152 Pitch. Square (in.) 0.738 0.640 0-.50 0.580 0.506 0.558 0.55w 0.563 0.563 0.496 0.496 O.D. (in.) 0.570 0.493 0.430 0.379, ... ' 0.440 .0,382 0.422 0.422 0.422 0.422 0.374 0.360 Clad Thickness (mils.) 35.5 34 26.5 23.5 - 26 "25 16.5 24.3 16.5 24.3 22.5 22.5 Clad Material Zr 2 Zr2 Zr 4.. Zr4- .. Zr 4 :Zr,4.'- st ,Zr4 sat Zr4 Zr4 Zr4 Pellet O.D. (in.) 0.488 0.416 0.370 0.3232 0.3795 01325 0.3835. 0.3659 0.I835 0.3659 0.3225 03088 Pellet Length (in.i - 0.375 .;.1-0.6,10 9-0** .0.600 0.600 0.600 0.600 0.530 0.530 Gap. a*idal (mils.) 5.5 4.5 3.5 3.1 . . 4.3 .3.5 2.8. 3.8 2.8 3.8 3.3 3.3 Density tSTD) 92-&05.0 93.950 93.0.950 .94.7 93.0.94.0 92.0 .93.0-94.0 92.0 95.0 95.0 Poison Gd,0. Gd.0. None None,. BCIAI,40. BCIAl0, - ..

Nonfueled Rods Number 0 17 25 6 ".6';. - 16- 17 .21 21 25 25 Material - Zr2 Zr4 *;*4Zr " ". 304sst Zr 4 '304 sst Zr4 Zr4 Zr4 Zr4 SSpacer Grids Number 7 7 8 Inconel 2 18 Material Inconel X Inc'onel X tycuei (Zr8 8) 7 s.Zr.4 SOURCE: American Nuclear Socie ty (1988).

E GLOSSARY Actinide: Any of a series of chemically similar radioactive elements with atomic numbers ranging from 89 (actinium) through 103 (lawrencium). This group includes uranium and plutonium.

Alpha particle: Two neutrons and two protons bound as a single particle (a helium nucleus) emitted from certain radioactive isotopes when they undergo radioactive decay.

Bare-fuel cask: See Cask.

Beta particle: A charged particle consisting of a positron or electron emitted from certain radioactive isotopes when they undergo radioactive decay.

Beyond-design-basis accidents: Technical expression describing accident sequences outside of those used as design criteria for a facility. Beyond-design-basis accidents are generally more severe but are judged to be too unlikely to be a basis for design.

Boiling water reactor (BWR): A type of nuclear reactor in which the reactor's water coolant is allowed to boil to produce steam. The steam is used to drive a turbine and electrical generator to produce electricity.

Burn-up: Measure of the number of fission reactions that have occurred in a given mass of nuclear fuel, expressed as thermal energy released multiplied by the period of

'operation and divided by the mass of the fuel. Typical units are megawatt-days per metric ton of uranium (MWd/MTU) or gigawatt-days per metric ton of uranium (GWd/MTU).

Canister-based cask: See Cask.

Cask: Large, typically cylindrical containers constructed of steel and/or reinforced concrete that are used to store and/or transport spent nuclear fuel. Casks designed for storage of spent nuclear fuel can be of two types: "bare-fuel" or "canister-based." In bare-fuel casks, spent fuel is stored in a fuel basket surrounded by a heavily shielded

• and leak-tight container. In canister-based casks, the fuel is enclosed in a leak-tight steel cylinder, called ;a canister, which has a welded lid. The canister is placed in a heavily shielded cask overpack. Casks can be single-, dual-, .or multiple-purpose, indicating that they can be used, respectively, for storage (also called storage-only casks), for storage. and transportation, and for storage, transportation, and geologic disposal. There are no true multi-purpose casks for spent fuel currently available on the market.

Cesium-137: Radioactive isotope that is one of the products of nuclear fission.

-Chain reaction: A series of fission reactions wherein the neutrons released in one fission event stimulate the next fission event or events.

108

GLOSSARY 109 Cladding: Thin-walled metal tube that forms the outer jacket of a nuclear fuel rod. It prevents corrosion of the nuclear fuel and the release of fission products into the coolant. Zirconium alloys (also called zircaloy,see below) are common cladding materials in commercial nuclear fuel.

Conduction: In the context of heat transfer, the transfer of heat within a medium through a diffusive process (i.e., molecular or atomic collisions).

Containment structure: A robust, airtight shell or other enclosure around a nuclear reactor core to prevent the release of radioactive material to the environment in the event of an accident.

Convection: Heat transfer by the physical movement of material within a fluid medium.

Cooling time: The amount of time elapsed since spent fuel was discharged from a nuclear reactor.

Core: That portion of a nuclear reactor containing the fuel elements.

Criticality: Term used in reactor physics to describe the state in which the number of neutrons released by the fission process is exactly balanced by the neutrons being absorbed and escaping the reactor core. At criticality, the nuclear fission chain reaction is self-sustaining.

Decay heat: Heat produced by the decay of radioactive isotopes contained in nuclear fuel.

..Decay, radioactive: Disintegration of the nucleus .of an unstable element by the spontaneous emission of charged particles (alpha, beta, positron) or photons of energy (gamma radiation) from the nucleus, spontaneous fission, or electron capture.

Depleted uranium: Uranium enriched in the element uranium-238 relative to uranium-235 compared to that usually found in nature. Also, uranium in which the uranium-235 content has been reduced through a physical process.

Design basis phenomena: Earthquakes, tornadoes, hurricanes, floods, and other events that a nuclear facility must be designed and built to withstand without loss of systems, structures, and components necessary to ensure public health and safety.

Design basis threat: In the context of this study, hypothetical ground assault threat against a commercial nuclear power plant. Some generic elements of the design basis threat are described in Title 10, Section 73.1(a) of the Code of Federal Regulations (10 CFR 73.1(a)).

Dirty bomb: See RadiologicalDispersalDevice.

Dry storage: Out-of-water storage of spent nuclear fuel in heavily shielded casks.

110 SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Drywell: The containment structure enclosing a boiling water nuclear reactor vessel. The drywell is connected to a pressure suppression system and provides a barrier to the release of radioactive material to the environment under accident conditions.

Dual-purpose cask: See Cask.

Fissile material: Material that undergoes fission from thermal (slow) neutrons. Although sometimes used as a synonym for fissionable material, the term "fissile" has acquired this more restricted meaning in nuclear reactor technology. The three primary fissile materials are uranium-233, uranium-235, and plutonium-239.

Fission: Splitting of a nucleus into at least two nuclei accompanied by the release of neutrons and a relatively large amount of energy.

Fissionable: Material that is capable of undergoing fission from fast neutrons.

Fission products: Nuclei resulting from the fission of elements such as uranium.

Fuel assembly: A square array of fuel rods.

Fuel pellet: A small cylinder of uranium usually in a ceramic form (uranium dioxide, U0 2 ),

typically measuring about 0.4 to 0.65 inches (1.0 to 1.65 centimeters) tall and about 0.3 to 0.5 inch (0.8 to 1.25 centimeters) in diameter.

Fuel reprocessing: Chemical processing of reactor fuel to separate the unused fissionable material (uranium and plutonium) from waste material.

Fuel rod: Sometimes referred to as a fuel element or fuel pin. A long, slender tube that holds the uranium fuel pellets. Fuel rods are assembled into bundles called fuel assemblies.

Gamma ray: Electromagnetic radiation (high-energyphotons) emitted from certain radioactive isotopes when they undergo radioactive decay.

Half-life (radioactive): Time required for half the atoms of a radioactive substance to undergo radioactive decay. Each radioactive isotope has a unique half-life. For example, cesium-137 decays with a half-life of 30.2 years, and plutonium-239 decays with a half-life of 24,065 years.

Independent Spent Fuel Storage Installation (ISFSI): A facility for storing spent fuel inwet pools or dry casks as defined in Title 10, Part 72 of the Code of Federal Regulations.

Irradiation: Process of exposing material to radiation, for example, the exposure of nuclear fuel in the reactor core to neutrons.

Isotope: Elements that have the same number of protons but different numbers of neutrons.

For example, uranium-235 and uranium-238 are different isotopes of the element uranium.

GLOSSARY ill Loss-of-pool-coolant event: A postulated accidental or malevolent event that results in a loss of the water coolant from a spent fuel pool at a rate in excess of the capability of the water makeup system to restore it.

Megawatt: One million watts.

MELCOR: A computer code developed by Sandia National Laboratories for use in analyzing severe reactor core accidents. The code has been adapted to model fluid flow, heat transfer, fuel cladding oxidation kinetics, and fission product release phenomena associated with spent fuel assemblies in spent fuel pools in loss-of-pool-coolant events.

Metric ton: Weight unit corresponding to 1000 kg or approximately 2200 pounds.

Metric tons of uranium: See MTU.

Moderator: Material, such as ordinary water, heavy water, or graphite, used in a reactor to slow down high-energy neutrons.

MTU (metric tons of uranium): Unit of measurement of the mass for spent nuclear fuel, also expressed in metric tons of heavy metal (MTHM). It refers to the initial mass of uranium that is contained in a fuel assembly. It does not include the mass of fuel cladding (zirconium alloy) or the oxygen in the fuel compound.

Multi-purpose cask: See Cask.

MWe: Megawatts of electrical energy output from a power plant.

MWt: Megawatts of thermal energy output from a power plant.

Neutron: Uncharged subatomic particle contained in the nucleus of an atom. Neutrons are emitted from the nucleus during the fission process.

Open rack: A storage rack in a spent fuel pool that has open space and lateral channels -

between the cells for storing spent fuel assemblies to permit water circulation.

Overpack: Metal or concrete cask used for storage or transportation of a canister containing spent nuclear fuel. See Cask.

Owner-controlled area: That part of the power plant site over which the plant operator exercises control. This usually corresponds to the boundary of the site.

Pellet: See Fuel pellet.

Penetrate: To pass into, but not completely through, a solid object.

Perforate: To produce a hole that goes completely through a solid object.

Plutonium-239: A fissile isotope of plutonium that contains 94 protons and 145 neutrons.

112 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Pressurized water reactor (PWR): A type of nuclear reactor in which the reactor's water coolant is keptat high pressure to prevent it from boiling. The coolant transfers its heat to a secondary water system that boils into steam to drive the turbine and generator to produce electricity.

Probabilistic risk assessment: A systematic, quantitative method to assess risk (see below) as it relates to the performance of a complex system.

Protected area: A zone located within the owner-controlled area of a commercial nuclear power plant site in which access is restricted using guards, fences, and other barriers.

psia: Unit of pressure, pounds per square inch absolute, that is the total pressure including the pressure of the atmosphere.

Radioactivity: Spontaneous transformation of an unstable atom, often resulting in the emission of particles (alpha and beta) or gamma radiation. The process is referred to as radioactive decay.

Radiological Dispersal Device (RDD): A terrorist device in which sources of radioactive material are dispersed by explosives or other means. Also referred to as a dirty bomb.

Radiological sabotage: Any deliberate act directed against a nuclear power plant or spent fuel in storage or transport that could directly or indirectly endanger the public health and safety by exposure to radiation.

Radionuclide: Any form of an isotope of an element that is radioactive.

Re-racking: Replacement of the existing racks in a spent fuel pool with new racks that increase the number of spent fuel assemblies that can be stored.

Risk: The potential for an adverse effect from an accident or terrorist attack. This potential can be estimated quantitatively if answers to the following three questions can be obtained: (1) What can go wrong? (2) How likely is it? (3) What are the consequences?

Safety: In the context of spent fuel storage, measures that protect storage facilities against failure, damage, human error, or other-accidents that would disperse radioactivity in the environment.

Safeguards: As used in the regulation of domestic nuclear facilities and materials, the use of material control and accounting programs to verify that all nuclear material is properly controlled and accounted for, and also the use of physical protection equipment and security forces to protect such material.

Safeguards information: Information not otherwise classified as National Security Information or Restricted Data that specifically identifies a U.S. Nuclear Regulatory Commission licensee's or applicant's detailed (1) security measures for the physical

GLOSSARY 113 protection of special nuclear material or (2) security measures for the physical protection and location of certain plant equipment vital to the safety of production or utilization facilities (10 CFR 73.2). The U.S. Nuclear Regulatory Commission has the authority to determine whether information is "safeguards information."

Security: In the context of spent fuel storage, measures to protect storage facilities against sabotage, attacks, or theft.

Shaped charge: A demolition and wall penetration or perforation device that uses high explosive to create a high-velocity jet of material.

Single-purpose cask: See Cask.

Special nuclear.material: Fissile elements such as uranium and plutonium.

Spent fuel: See Spent nuclearfuel.

Spent fuel pool: A water-filled pool that is used at all commercial nuclear reactors for storage of spent (used) fuel elements after their removal from a nuclear reactor.

Spent fuel pools are constructed of reinforced concrete and lined with stainless steel.

The inside of the pool has storage racks to hold the spent fuel assemblies and may contain a gated compartment to hold a spent fuel cask while it is being loaded and sealed.

Spent (or used or irradiated fuel) nuclear fuel: Fuel that has been "burned" in the core of a nuclear reactor and is no longer efficient for producing electricity. After discharge from a reactor, spent fuel is stored in water-filled pools (see Wet storage)for shielding and cooling.

Storage-only cask: See Cask.

Thermal power: Total heat output from the core of a nuclear reactor.

Uranium-235: A fissile isotope of uranium that contains 92 protons and 143 neutrons. It is the principal nuclear fuel in nuclear power reactors.

Uranium-238: An isotope of uranium that contains 92 protons and 146 neutrons.

Vital area: A zone located within the protected area of a commercial nuclear power plant site that contains the reactor control room, the reactor core, support buildings, and the spent fuel pool. It is the most carefully controlled and guarded part of the plant site.

Watt: Unit of power.

Watt-hour: Energy unit of measure equal to one watt of power supplied for one hour.

Wet storage: Storage of spent nuclear fuel in spent fuel pools.

114 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Zircaloy: Zirconium alloy used as cladding for uranium oxide fuel pellets in reactor fuel assemblies.

Zirconium cladding fire: A self-sustaining, exothermic reaction caused by rapid oxidation of zirconium fuel cladding (zircaloy) at high temperatures.

F ACRONYMS ACRS: Advisory Committee on Reactor Safeguards BAM: Bundesanstalt ffir Materialforschung und -prOfung.

BMU: Bundesministerium fOr Umwelt, Naturschutz und Reaktorsicherheit BNL: Brookhaven National Laboratory BWR: Boiling Water Nuclear Reactor (see Appendix E)

CFD: Computational Fluid Dynamics DBT: Design Basis Threat (see Appendix E)

DHS: United States Department of Homeland Security DOE: United States Department of Energy EPRI: Formerly referred to as the Electric Power Research Institute GAO: United States Government Accountability Office (formerly the General Accounting Office)

S.. GESMO: Final Generic Environmental Statement on the Use of Recycled Plutonium in Mixed Oxide Fuel in Light-Water Cooled Reactors GNB: Gesellschaft fir Nuklear-Beh~lter, mbH GNS: Gesellschaft for Nuklear-Service, mbH GNSI: General Nuclear Systems, Inc.

GRS: Gesellschaft fOr Anlagen- und Reaktorsicherheit, mbH GWd/MTU: Gigawatt-Days per Metric Ton of Uranium (see Bum-up in Appendix E)

INL: Idaho National Laboratory (formerly Idaho National Engineering and Environmental Laboratory)

ISFSI: Independent Spent Fuel Storage Installation HSK: Die Hauptabteilung fOr die Sicherheit der Kemanlagen MTU: Metric Tons of Uranium (see Appendix E)

MWd/MTU: Megawatt-Days per Metric Ton of Uranium (see Bum-up in Appendix E)

NPP: Nuclear Power Plant NRC: National Research Council PFS: Private Fuel Storage PWR: Pressurized Water Nuclear Reactor (see Appendix E)

RDD: Radiological Dispersal Device (see Appendix E)

RPG: Rocket-Propelled Grenade 115

114 SAFETY AND SECURITY OF COMMERCIAL SPENT FUEL STORAGE Zircaloy: Zirconium alloy used as-cladding for uranium oxide fuel pellets in reactor fuel assemblies.

Zirconium cladding fire: A self-sustaining, exothermic reaction caused by rapid oxidation of zirconium fuel cladding (zircaloy) at high temperatures.

F ACRONYMS ACRS: Advisory Committee on Reactor Safeguards BAM: Bundesanstalt f~r Materialforschung und -prOfung BMU: Bundesmiriisterium fOr Umwelt, Naturschutz und Reaktorsicherheit BNL: Brookhaven National Laboratory BWR: Boiling Water Nuclear Reactor (see Appendix E)

CFD: Computatonal Fluid Dynamics DBT: Design Basis Threat (see Appendix E)

DHS: United States Department of Homeland Security DOE: United States Department of Energy EPRI: Formerly referred to as the Electric Power Research Institute GAO: United States Government Accountability Office (formerly the General Accounting Office)

GESMO: Final Generic Environmental Statement on the Use of Recycled Plutonium in Mixed Oxide Fuel in Light-Water Cooled Reactors GNB: Gesellschaft fOr Nuklear-Beh5lter, mbH GNS: Gesellschaft for Nuklear-Service, mbH GNSI: General Nuclear Systems, Inc.

GRS: Gesellschaft fOr Anlagen- und Reaktorsicherheit, mbH GWd/MTU: Gigawatt-Days per Metric Ton of Uranium (see Bum-up in Appendix E)

INL: Idaho National Laboratory (formerly Idaho National Engineering and Environmental Laboratory)

ISFSI: Independent Spent Fuel Storage Installation HSK: Die Hauptabteilung fOr die Sicherheit der Kemanlagen MTU: Metric Tons of Uranium (see Appendix E)

MWd/MTU: Megawatt-Days per Metric Ton of Uranium (see Burn-up in Appendix E)

NPP: Nuclear Power Plant NRC: National Research Council PFS: Private Fuel Storage PWR: Pressurized Water Nuclear Reactor (see Appendix E)

RDD: Radiological Dispersal Device (see Appendix E)

RPG: Rocket-Propelled Grenade 115

SAFETYAND SECURITY OF COMMERCIAL SPENT FUEL STORAGE 116 RSK: Reaktorsicherheitskommission TOW: Tube-Launched, Optically Tracked, Wire Guided [Missile] (see Appendix E)

USNRC: United States Nuclear Regulatory Commission

ISBN 0-309I-09647-2 o )Rn-ing nQts47g ii1E