Text

Response to Request for Additional Information Regarding Safety Analysis of Millstone Unit 1 Missing Fuel Rods
	ML021500428
Person / Time
Site:	Millstone
Issue date:	05/15/2002
From:	Price J; Dominion Nuclear Connecticut
To:	; Document Control Desk, NRC/FSME
References
	B18595
	Download: ML021500428 (35)
	v • d • e

Dominion",

Dominion Nuclear Connecticut, Inc.

Millstone Power Station Rope Ferry Road Waterford, CT 06385 MAY 1 5 2002 Docket No. 50-245 B18595 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station, Unit No. 1 Response to a Request for Additional Information Regarding Safety Analysis of Millstone Unit No.1 Missing Fuel Rods In a letter dated February 14, 2002,(1) the Nuclear Regulatory Commission staff submitted a request for additional information regarding the Safety Analysis of Millstone Unit No. 1 Missing Fuel Rods. The enclosure to this letter contains the response to the request for additional information obtained by Dominion Nuclear Connecticut, Inc. from Northeast Nuclear Energy Company, the former licensee and operator of Millstone Unit No. 1.

There are no regulatory commitments contained within this letter.

Should there be any questions Mr. David A. Smith at (860) 437-5840.

regarding this submittal, please contact Very truly yours, DOMINION NUCLEAR CONNECTICUT, INC.

J Ala. PýIce Site Vcy President - Millstone Enclosure (1) cc:

H. J. Miller, Region I Administrator J. B. Hickman, NRC Project Manager, Millstone Unit No. 1 T. J. Jackson, NRC Inspector, Region I, Millstone Unit No. 1 (1)

S. A. Richards, U.S. Nuclear Regulatory Commission letter to J. Alan Price, "Safety Analysis of Millstone Unit 1 Missing Fuel Rods," dated February 14, 2002.

ý\\ (D CA

Docket No. 50-245 B18595 Enclosure Millstone Nuclear Power Station, Unit No. 1 Response to a Request for Additional Information

SNortheast 107 Selden Street, Berlin, CT 06037 Utilities System Northeast Utilities Service Company P.O. Box 270 Hartford, CT 06141-0270 (203) 665-5000 May 10, 2002 Mr. J. Alan Price Site Vice President - Millstone Dominion Nuclear Connecticut, Inc.

Rope Ferry Road Waterford, Connecticut 06385

Subject:

Response to NRC Request for Additional Information re: Safety Analysis of Millstone Unit 1 Missing Fuel Rods

Dear Mr. Price:

On February 14, 2002, the Nuclear Regulatory Commission sent Dominion Nuclear Connecticut a request for additional information related to a report prepared by Dr. Michael T. Ryan, "Safety Analysis of Millstone Fuel Rods Potentially Disposed of in Either Barnwell, South Carolina or Hanford Washington Commercial, LLRW Disposal Sites" (the "Ryan Report"). This letter forwards Northeast Utilities' ("NU's") final response to the questions posed in that request.

Specifically, the enclosed response provides a supplement authored by Dr. Ryan addressing the impact of the possible addition of the two fuel rods to the inventory of either LLRW site on an inadvertent intruder. Additionally, as requested by the NRC, the enclosure provides information describing the relationship between information in NU's January 11, 2001, Licensee Event Report and the quantities of radioactive materials described in the Ryan Report. Finally, the response addresses the comments and questions posed by state regulators in South Carolina and Washington attached to the NRC's request.

If you have any questions regarding this response please contact me at 860-665-3141.

Sincerely, Richard M. Kacich Director, Special Projects Enclosure 0S3422 REV. 1-94

ENCLOSURE 1 NNECO's Response to NRC's Request for Additional Information

1.

The staff notes that an inadvertent intruder scenario is not addressed in the Ryan Report. Thus, this scenario needs to be addressed by Dominion Nuclear Connecticut, Inc. in order for the staff to make the necessary safety finding.

Dr. Ryan's analysis of the impact on an inadvertent intruder of the possible addition of the two Millstone Unit 1 fuel rods to the inventory of either LLRW site, "Evaluation of the Presence of Two Spent Fuel Rods on the Inadvertent Intruder, A Supplement to Safety Analysis of Millstone Fuel Rods Potentially Disposed In Either the Barnwell, South Carolina or Hanford, Washington Commercial LLRW Disposal Sites," is provided as Attachment 1.

2.

The Licensee Event Report submitted by Northeast Nuclear Energy Company on January 11, 2001, has quantities of radioactive material that are different from the Ryan Report. These discrepancies should be reconciled.

The quantities reported in the LER of January 11, 2001, were derived from a different set of data than those used by Dr. Ryan in his October 2001 report.

Specifically, to calculate: (a) the "Total Uranium in the 2 Fuel Rods;" (b) the "Total Uranium 235 in the 2 Fuel Rods;" (c) the Total Plutonium in the 2 Fuel Rods;" and (d) the "Total Fissile Plutonium in the 2 Fuel Rods" in the LER, Northeast Nuclear Energy Company ("NNECO") used the data applicable to MS-557 that formed the basis for the input into the Form 742, which was submitted to the NRC in October 2000. That data reflected the calculated amounts of the relevant isotopes of radioactive material in the entire, intact, MS-557 assembly. The data did not reflect the amounts of the material on a rod-by-rod basis. Therefore, to derive the amounts of material in the two fuel rods, NNECO took the calculated amounts for the entire assembly, divided by 49 (to reflect the number of fuel rods in the original assembly), and then multiplied by two to determine the quantities in two fuel rods. Thus, this methodology produced quantities of radioactive material in the two unaccounted for rods that reflected the average of the materials found in the individual rods in MS-557. It, therefore, reflected the average enrichment of the rods that made up MS-557, i.e., 2.07%. But, all of the fuel rods in an assembly do not have the same enrichment. In fact, the center spacer capture rod and tie rod that were unaccounted for from MS-557 had an enrichment of 2.44%.

On January 12, 2001, the day after the issuance of the LER, Duke Engineering Services

("Duke") provided NNECO with an analysis of the radionuclide source terms and radiation fields associated with MS-557, as a whole, and for the two fuel rods. Duke provided NNECO with Rev. 1 to that analysis on June 6, 2001, to expand the list of radionuclides included in various tables. Dr. Ryan used Revision 1 of the Duke report as the basis for the entries in Table I of his report. Specifically, Dr. Ryan used the data

from Duke's Table 5.11 to calculate the mass (in grams) of U-235 and Pu-239 in December 2000 (Year 28.25 in Duke's Table 5.11). Because the masses reported in Table 5.11 are the masses for a single rod, Dr. Ryan doubled the masses to reflect the mass contained in the two rods. Similarly, Dr. Ryan used the data from Duke's Table 5.10 (doubled) to report the activity levels (in Curies) of 1-129 and Tc-99 in December 2000 (Year 28.25 in Duke's Table 5.10). To determine the total Uranium, Dr. Ryan took the activity level for the six Uranium isotopes (U-232, U-234, U-235, U-236, U-237, and U-238) from Duke's Table 5.10, converted the activities to mass, and doubled the mass to reflect the total grams of uranium present in the two spent fuel rods.

As noted earlier, the LER reflected the average masses of isotopes found in rods with an enrichment of 2.07%. Using an ORIGEN-2 computer run, the Duke calculations used in Dr. Ryan's report calculated the amount of activity and mass for the two unaccounted for rods using their actual enrichment of 2.44%.

Additionally, the data underlying the Form 742 (upon which the LER was based) used the "as built" fuel assembly Uranium weight of 192 kg. The Duke calculations (upon which the Ryan Report was based) used the more conservative "design" fuel assembly Uranium weight of 200 kg.

3.

The States of South Carolina and Washington have provided their comments on the Ryan Report. Copies of those letters are attached. [Letters omitted.] Please address their comments in your response to this request for additional information.

NU's responses to comments and answers to the questions posed by the regulators in the States of South Carolina and Washington are provided in the following numbered paragraphs.

South Carolina SC1 We agree with the findings of the report that the methods used for transportation and disposal of the shipments that potentially contained the fuel rods would not have resulted in any increased risk to the public or to workers at the disposal facility. Also, environmental sampling at the Barnwell facility has not indicated the migration of any radionuclides in the fuel rod inventory and therefore the short term impacts are anticipated to be manageable.

NU agrees that the impacts, if any, of the possible addition of two fuel rods to the radionuclide inventory at the Bamwell facility are manageable.

SC2 We do not agree with the findings of the report that the fuel rods are an insignificant addition to the existing inventory. In fact, based on the information provided to our office by Chem-Nuclear, the increase in the quantities of transuranic radionuclides is not insignificant. [Table omitted.]

2

In concluding that the two fuel rods would pose an insignificant addition to the inventory at the Barnwell LLRW facility, Dr. Ryan noted that the two fuel rods, if present, would not introduce any new isotopes and that, on the whole, the rods' isotopes were a very small addition to the total radioactive material inventory. The South Carolina Department of Health and Environmental Control (DHEC) has simply pointed out that for some individual isotopes, it would not characterize the percentage of the increase as "insignificant." Regardless of the adjective used, Dr. Ryan's point remains valid. The overall increase in special nuclear material to the site inventory resulting from the possible presence of the two fuel rods does not significantly impact performance of the facility. Indeed the Pu, Am, and Cm isotopes cited by DHEC - even if a numerically "significant" percentage increase over the previous level - is not a significant factor in determining whether the rods will affect the site's performance. In fact, those isotopes are not particularly mobile and do not materially affect the site's performance. Finally, the radionuclides contained in the two fuel rods, if present at the facility, are contained within a stable, non-soluble ceramic matrix and, therefore, are less susceptible to migration than quantities of those same nuclides shipped to the facility from other sources.

SC3 Prior to drawing any final conclusions on the impacts of long-term site performance at Barnwell, an analysis should be performed applying the methodology used by Chem-Nuclear Systems, LLC in the Environmental Performance Assessment, the performance assessment for the Barnwell site.

NU understands that Chem-Nuclear Systems LLC and the State are addressing this issue and NU is not aware of any indication that the potential presence of the two fuel rods will adversely affect the site's performance.

SC4 The report does not address the inadvertent intruder scenario, and does not provide any recommendations on increased intruder protection or recommendation for increased site surveillance.

Discussion of the impact on the inadvertent intruder from the possible addition of the two Millstone Unit 1 spent fuel rods to the inventory of the Barnwell site is provided as. For the reasons discussed in that analysis, no additional enhancements beyond the existing intruder protections and site surveillance programs are necessary.

SC5 We recognize that the issues of both regulatory jurisdiction and ownership of the fuel rods may impact planning, liability, and financial responsibility for future management of the fuel rods. We recommend that the NRC and Millstone review these jurisdictional and ownership issues and work with South Carolina and Washington to resolve these issues as soon as possible.

NU agrees with the recommendation and has had numerous discussions with the affected state and federal regulators and facility licensees on a range of issues related to the possible presence of Millstone fuel rods. Exclusive regulatory jurisdiction over spent nuclear fuel resides in the NRC. We have urged the NRC to exercise that jurisdiction to 3

affirm, consistent with NU's safety analysis and inadvertent intruder analysis, that the potential inclusion of the Millstone fuel rods at either facility poses no significant risk to public health and safety, site workers, or to common defense and security. Moreover, handling of the spent nuclear fuel is not authorized without a license issued by the NRC.

Because the public interest is best served by leaving the fuel rods in place, we believe that the NRC should take the position that no actions to exhume or retrieve the fuel rods are warranted, appropriate, or authorized absent the Commission's prior written approval.

We are continuing our dialogue with the NRC, consistent with this objective.

Washington State WA1 While the report generally speaks accurately of disposal practices (i.e., LLRW disposal site is not a monitored retrievable storage facility), the site has shown that it can perform exhumation operations. In fact the latest retrieval (late October 2001) was performed in less than a week and with about 10 man-mrem exposure. While package retrieval is not routine, the operation is not "first-of-a-kind" as stated in the last paragraph on page 13. If warranted, retrieval of the package would involve significant health physics challenges.

NU agrees that retrieval of the two fuel rods from either facility would, at a minimum, involve significant health physics challenges and risks. The radiological and occupational risks, and potential cost of exhumation and retrieval are out of proportion to any potential benefit associated with exhumation. For the reasons described in the Ryan Report and the supplement provided in Attachment 1, retrieval or exhumation of the fuel rods, in the extremely unlikely events the rods are present at Hanford, is neither necessary nor advisable. As the NRC noted in its special inspection report, "because of the radiological controls in place at any of the possible locations of the missing fuel rods, realistically, there is no current threat to public health." Those risks are especially unwarranted at Hanford given the findings of the Fuel Rod Accountability Project (FRAP) that "there is no credible evidence, and certainly no clear and convincing evidence, proving that the rods were shipped to [Hanford]." (FRAP at page 5). So, too, the NRC concluded in its Inspection Report that there was only a "small opportunity" that the rods could have been shipped to Hanford, and that the "most likely" explanation is that the rods were inadvertently shipped to Barnwell in 1988. (NRC Inspection Report at 26.)

WA2 The condition of the fuel rods was not discussed in the report. Without supporting information, we believe the worst case scenario must be considered.

NU's Final FRAP Report considered the various possible conditions of the fuel rods. NU found no evidence supporting any condition for the two rods not addressed in this report.

Nor did the NRC's special inspection suggest evidence of any other condition. Whether the fuel rods were placed in a shipping liner intact or cut into segments does not alter the analysis or conclusions in the Ryan Report or the attached supplement.

WA3 Several years ago, the department allowed the intact disposal of the Portland 4

General Electric reactor vessel. This type of disposal was allowed, in part, due to (1) the immediate saving in worker dose that would occur if the reactor internals were not removed and sized for packaging, and (2) the reduction in the transportation (industrial) hazard due to making this only one shipment instead of several truck shipments. The same type of analysis is also valid in this evaluation. While the projected dose rates during exhumation are very high, very little discussion in the report is directed at US Ecology's ability to successfully remove the disposed liner, once identified. US Ecology in calendar year 2000 was able to dispose of six very high radiation/high activity liners from Energy Northwest with about 100 man mrem/liner, due to careful planning, extensive use of mock-ups, and thorough debriefs. Obviously the industrial hazard is nonexistent if no attempt is made to exhume the liner (if present). On the other hand, US Ecology has an excellent industrial safety record working with radioactive materials of all types and radiation levels.

NU has no independent basis to assess the capabilities of U.S. Ecology to dispose of, exhume, or retrieve waste containers, however, NU does not question the ability of the LLRW licensees to safely dispose of radioactive waste. NU notes, however, that the burial of irradiated material differs substantially in scope and difficulty from the exhumation of irradiated waste - particularly if the waste being exhumed is believed to contain spent fuel rods. Thus, the issue here is whether exhumation is needed to protect public health and safety. The answer is clearly "no." Dr. Ryan's initial report addressed some of the engineering, operational, and ALARA concerns that would arise in any attempted exhumation of a buried Millstone liner. NU agrees that the projected worker dose rates during any exhumation would be very high and this worker exposure would not be offset by any reduction in long-term risk to workers, the public, or the environment.

WA 4 The report should consider the various inadvertent intruder scenarios, per NRC guidance.

Discussion of the impact on the inadvertent intruder of the possible addition of the two Millstone Unit 1 fuel rods to the inventory of the Hanford site is provided as Attachment

1.

WA5 With the discovery of water in a disposal liner sent to Barnwell, SC in May 1990, the potential for fuel rod degradation is higher. In lieu of further information as to how this liquid was discovered, the idea of significant water in the liner with two fuel pins that contain isotopes that are performance assessment drivers (i.e., 1-129 and Tc-99) supports further investigations. A primary purpose of the additional investigations is the root cause for the water in the disposal liner and whether any of the Hanford liners could have contained free-standing liquids.

On May 9, 1990, workers at the Chem Nuclear facility in Barnwell opened a TN-RAM cask from Millstone at a slit trench and noticed that water emerged from the cask. Later, Chem Nuclear personnel de-watered the cask completely and buried the liner, in 5

accordance with applicable standards and procedures and with the approval of South Carolina officials.

A root cause investigation ensued and concluded that the root cause of the event was an inadequate design in the cask liner drain system, which allowed the screen over the drain holes to become plugged. In the root cause investigation and in the Notice of Violation associated with this event, the company and the NRC also noted that the Waste Chem de watering procedure for this cask did not contain a method to determine the amount of water drained and noted the existence of a discrepancy between the Safety Analysis Report for the TN-RAM cask and the Waste Chem procedure. Specifically, the procedure did not require the cask's dryness verification test to be conducted at the required vacuum of 10 mbar. (The procedure permitted testing at any vacuum above 10 mbar.) The NRC noted that if this deficiency had been identified and corrected, the operators performing the dryness testing would likely have realized that there was still a significant amount of water in the cask before releasing it for shipment.

Given the circumstances surrounding this event, there is no reason to believe that the three Millstone Unit 1 shipments to Hanford in 1985 contained water. First, the inadequate cask liner drain design and the discrepancy between the Waste Chem procedure and the Safety Analysis Report pertained to the TN-RAM cask. Millstone did not ship any TN-RAM casks to Hanford. Rather, all three shipments were made in IF 300 casks. Second, there was no indication in the documents reviewed by the FRAP, or in the interviews conducted during the investigation, that suggested that any of the Hanford shipments contained water in excess of any applicable limits. Third, as the 1990 Barnwell event shows, even if water remained in the cask after shipment, the process of unloading and burial at the LLRW repository worked as intended and led to the discovery of the water before burial. In fact, the manifests for all three Hanford shipments indicate that after receipt, the recipient verified that: "Th[e] material meets license limits" [and]

"was disposed of in accordance with [the] license." Had there been water in the casks upon burial, the manifest and other related documents would likely provide some indication. As previously noted, the FRAP found no such indication.

Moreover, even if-contrary to the evidence - there were water in the casks, that fact would not support the conclusion that the presence of water in the disposal liner significantly increases the likelihood of migration of the radionuclides contained within the fuel rods. To the contrary, the two unaccounted for spent fuel rods were designed to be used in a boiling water reactor. Thus, boiling water reactor fuel operates in a high temperature, high-radiation aqueous environment. The fuel rods are then stored in water in the spent fuel pool for many years. More significantly, the radionuclides are contained within ceramic pellets, which for all practical purposes, are not susceptible to degradation in water. Accordingly, these highly stable materials are less susceptible to migration than radionuclides present from other sources.

WA6 Using the data provided in Table 1 and on page 4 and assuming the fuel pins were about 0.5 inch in diameter with an active fuel region of 12 feet it was confirmed that both 1-129 and Tc-99 concentrations were at levels greater than Class C.

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NU has no comment on this calculation. However, the particular label given to these rods, if present at Hanford at all, does not alter the analysis of the radiological characteristics or health and safety impacts of their possible burial.

WA7 Dr. Ryan's report does not discuss potential mitigations for the burial of high-level waste or waste at levels greater than Class C. The department believes such a discussion would be helpful.

The Ryan Report, as supplemented by Attachment 1, addresses the radiological health and safety impacts of the possible inclusion of two Millstone spent fuel rods. As noted above, the label applied to these materials does not alter their radiological characteristics or health and safety impacts of their possible burial. The analysis indicates that the significant design features of the disposal facility and existing programs to protect the public health and safety are sufficient. Moreover, as discussed in Dr. Ryan's supplemental report, the Department of Health has permitted the disposal of greater than Class C waste at the Hanford LLRW facility. For example, the Department accepted the use of waste averaging to permit the burial of the intact Trojan reactor vessel, even though that vessel contained irradiated internals with radionuclides at concentration levels that were greater than Class C. Thus, the Department, through waste averaging, has recognized that concentration levels alone in individual waste items are not a complete measure of the risks that must be managed. Accordingly, no additional mitigating measures are necessary or appropriate.

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ATTACHMENT 1 Evaluation of the Presence of Two Spent Fuel Rods on the Inadvertent Intruder A Supplement to Safety Analysis of Millstone Fuel Rods Potentially Disposed in Either the Barnwell, South Carolina or Hanford, Washington Commercial LLRW Disposal Sites By Michael T. Ryan Ph.D., C.H.P.

I.

Introduction This analysis supplements an earlier report, "Safety Analysis of Millstone Fuel Rods Potentially Disposed in Either the Barnwell, South Carolina or Hanford, Washington Commercial LLRW Disposal Sites" (Safety Analysis). Specifically, this supplemental analysis responds to a request by the NRC, and state regulators in South Carolina and Washington, to consider the impact of the potential presence of the two Millstone fuel rods on the "inadvertent intruder." This analysis first addresses the purpose of the inadvertent intruder analysis, as that term is used in NRC licensing requirements for new land disposal facilities for radioactive wastes, and then considers the possible incremental impacts, if any, on the performance of either facility. The analysis shows that the possible disposal of the two Millstone fuel rods will not have any impact on an inadvertent intruder not accommodated by plans and programs already fully in place at both low-level radioactive waste ("LLRW") facilities.

II.

Background

The two Millstone spent fuel rods, if assumed to be disposed of at either Hanford or Barnwell, would not introduce ay new radionuclides into the inventories at these sites. Both sites already contain the same radionuclides, some in far greater quantities, than those contained in the fuel rods. This analysis will consider the two Millstone Unit 1 spent fuel rods as a hypothetical addition to the inventory of both sites. Specifically, this analysis will show, based on the radioactive material inventory in the Millstone fuel rods, that the intruder would be adequately protected by the current plans for intruder protection for each site.

The two Millstone fuel rods are not the only components disposed of in these facilities that contain locally high concentrations of radioactive material. High concentrations of radionuclides lawfully exist at the disposal facilities because the NRC1, state regulators2 and 10 C.F.R 61.55 (a)(8) ("The concentration of a radionuclide may be averaged over the volume of the waste, or weight of the waste if the units are expressed as nanocuries per gram."). See also NRC Final Branch Technical Position on Concentration Averaging and Encapsulation, Jan. 17, 1995, at Section 3.3.1 (averaging involving primary gamma emitters).

2 See, e.g., Washington State Department of Health, Technical Evaluation Report re:

Trojan Reactor Vessel, Sept. 1998, at Section 3.1 (relying on Section 3.9 of the NRC Branch Technical Position of Jan. 17, 1995).

facility procedures-permit waste averaging. By using waste averaging to determine the acceptability of waste shipments, both sites are licensed to dispose of some materials with concentrations that, on a piece-by-piece basis, contain greater than Class C concentrations of radioactive materials. This disposal is permissible because the concentration in the greater than Class C material is not considered in isolation. Rather, the material containing the locally high concentrations is considered with the other similar material in the waste package, so that the average concentration in the waste package is acceptable for disposal as Class C waste.

For example, Hanford used waste averaging to permit burial of the entire Trojan reactor vessel, along with its highly activated internals.- The greater volume of the vessel was averaged with the less massive -- but highly activated -- internals to permit disposal within allowable limits. This approach did not compromise the performance of the site, or call into question the pre-existing protections for inadvertent intruders. Irradiated hardware has already been considered in the performance assessments for both LLRW facilities and in the design considerations, including intruder barriers, that established the appropriate depth and method of disposal.

Historically, the Hanford site has received approximately: 27,518,181 grams of uranium (reported as pounds of depleted uranium from 1965-1980); 101,915 grams of U-235; 25,060 grams of plutonium (reported as Pu-239 and Pu-241); and 1,655,100 Ci, in total.- (The Washington State Department of Health and the licensee are currently updating these quantities and these numbers may be revised to lower amounts.) These amounts far exceed the amounts added in each category of radioactive material contained in the two Millstone fuel rods.

Likewise, the Barnwell site has already received 5,830,000,000 grams of total uranium, 3,200,000 rams of U-235, 212 grams of Pu-239, and 7,100,000 Ci of total radioactive material inventory.- Again, the two Millstone fuel rods would not have a significant effect on the inventory at Barnwell.

Finally, both facilities routinely accept and dispose of ion exchange resins, solidified wastes, and large components containing all of the radioactive materials present in the Millstone fuel rods. Acceptance of these wastes is appropriate, authorized, and well within the programs, See, e.g., Barnwell Waste Management Facility Site Disposal Criteria, Section 16.3.

Washington State Department of Health, Technical Evaluation Report re: Trojan Reactor Vessel, Sept. 1998, at Section 3.1 (relying on Section 3.9 of the NRC Branch Technical Position of Jan. 17, 1995).

See Table 2, Safety Analysis of Millstone Fuel Rods Potentially Disposed on Either the Barnwell, South Carolina or Hanford, Washington Commercial LLRW Sites, M.T. Ryan (2001).

6 Id.

2

plans, and capabilities of each facility to safely manage the wastes during existing waste disposal operations, as well as during closure and post closure operations.

III.

Preliminary Considerations Before discussing the specific inadvertent intruder scenarios, it is important to put these scenarios into context. Specifically, the likelihood that an inadvertent intruder would actually encounter the two Millstone spent fuel rods at either facility is extremely remote.

At Barnwell, the LLRW disposal site consists of 235 acres (1 acre = 43,560.18 ft2).7 The probability of an intruder selecting the exact location above the fuel rods is 6.1 x 10-8 or approximately 6 in 100 million (100,000,000). To calculate this probability, note that the area of the rods themselves is 0.625 ft2 (13 feet 2 inches long by 0.57 inches in diameter) and the area of the disposal facility is 235 acres. If the probability of intrusion is equal anywhere on the site, the probability of hitting the fuel rods is the area of the rods divided by the area of the site, or 10,236,642 ft2.

Similarly, very low probabilities exist at the Hanford facility. The 100 acre US Ecology site-is in the center of DOE's Hanford Reservation. The likelihood of an intruder selecting a spot above the Millstone fuel rods (if disposed of there at all) within the 100 acres of the US Ecology site is 1.4 x 10-7 or approximately 1 in 10 million (10,000,000). Again, the projected area of the fuel rods is divided by the square footage corresponding to the 100 acre disposal site.

Although the NRC has not adopted a specific probability that is sufficient to deem an event speculative or remote, the Commission recently approved an Atomic Safety and Licensing Board decision that concluded that an accident event that had a 2 in 10 million per reactor year probability of occurrence was too speculative and remote to require the preparation of an environmental impact statement.9 Using this standard, the likelihood that an inadvertent intruder would encounter the fuel rods at either Barnwell or Hanford is remote and speculative.

Wholly apart from the statistical probabilities, the protections associated with the long term operation at the Hanford site provide substantial assurance that no potential intruder could undertake drilling, home construction, and agricultural activities undetected. As noted above, the LLRW facility is located within the Central Plateau of the approximately 560 square mile Hanford Federal Reservation.1° Given the large quantities of radioactive material wastes of all Letter from V. Ichimura to M.T. Ryan, March 18, 2002.

_8 Sublease between The State of Washington, represented by the Department of Commerce and Economic Development, and Nuclear Engineering Company, February 26, 1976, at Article I.

Carolina Power & Light, 53 NRC 370 (2001); 53 NRC 239 (ASLB 2001).

10 U.S. Department of Energy, Richland Operations Office, Hanford Site Columbia River Corridor Cleanup, Report to Congress, April 2001.

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types that are present in the 200 Areas of the Central Plateau, and the massive clean-up efforts that must occur, long-term monitoring and institutional controls will likely continue at the Central Plateau for the indefinite future, and certainly long after US Ecology closes its LLRW facility, currently scheduled for 2063. Indeed, the 200 Areas of the Central Plateau are home to a large number of facilities formerly used for spent nuclear fuel processing and plutonium metal production, and to Hanford's 177 underground high-level radioactive waste storage tanks. 11 DOE has publicly acknowledged that to transition the federal site at Hanford to long-term stewardship, it will develop monitoring and stewardship plans to protect the environment and public health "in perpetuity."-l Given these required federal actions, there is no realistic chance that an intruder could occupy the LLRW facility and perform the home building, well drilling, or crop growing activities without detection. The Department of Health specifically recognized the reality of this federal presence in its Technical Evaluation of the Trojan reactor vessel. Specifically, the Department noted that, "[w]hile co-locating disposal facilities does not preclude the public from establishing a presence on or around the [commercial] facility, long-term [federal] government oversight of the area is a virtual reality.'13 IV.

The Inadvertent Intruder Scenarios A.

Regulatory Origin and Purpose NRC regulations at 10 CFR Part 61, "Licensing Requirements for Land Disposal of Radioactive Waste," establish the procedures, criteria, and terms and conditions for licensing new radioactive waste land disposal facilities. 10 CFR § 61.7 establishes the safety objectives for the disposal of radioactive waste in near-surface disposal facilities. These safety objectives include: (1) protection of the public from releases of radioactive material; (2) protection of individuals from inadvertent intrusion; (3) protection of individuals during operation; and (4) ensuring stability of the site after closure. An "inadvertent intruder" is defined in 10 CFR § 61.2 as:

A person who might occupy the disposal site after closure and engage in normal activities, such as agriculture, dwelling construction, or other pursuits in which the person might be unknowingly exposed to radiation from the waste.

The inadvertent intruder scenario is simply an analytical tool, based on conservatively developed hypothetical assumptions, that is used to determine whether the characteristics of new, LLRW disposal facilities are sufficient to protect inadvertent intruders from radiation exposure.

The regulations do not contemplate the use of the inadvertent intruder scenario to determine the 11 Id.

12 Id.

13 Washington State Department of Health, Technical Evaluation Report re: Trojan Reactor Vessel, Sept. 1998, at Section 3.2.2.

4

acceptability for disposal of specific waste packages. 10 CFR § 61.42 provides the performance objective for protection of individuals from inadvertent intrusion into land disposal facilities. It states that:

Design, operation, and closure of the land disposal facility must ensure protection of any individual inadvertently intruding into the disposal site and occupying the site or contacting the waste at any time after active institutional controls over the disposal site are removed.

Protection of inadvertent intruders involves two principal controls: (1) institutional controls over the site, and (2) designating which waste could present an unacceptable risk to a hypothetical inadvertent intruder and disposing of this waste in a manner that provides some form of intruder barrier that prevents contact with this waste.14 More specifically, the NRC requires institutional controls after closure of a LLRW facility for 100 years when licensing new disposal facilities. For Class A and Class B wastes, no additional intruder protection features are required because these Class A and B wastes typically contain shorter-lived radionuclides in smaller concentrations. Class C wastes typically contain longer-lived radionuclides in higher concentrations. For Class C wastes, the facility must incorporate barriers that will protect an intruder for 500 years post-closure. A sufficient depth of burial is an acceptable intruder barrier.15 Additionally, NRC regulations note that there may be some instances where waste with concentrations greater than permitted for Class C would be acceptable for near-surface disposal and should be evaluated on a case-by-case basis.16 For example, in reviewing the U.S. Department of Energy's plans to close the clean-up of the HLW tanks at the Savannah River Site, the NRC issued an advisory opinion to DOE in which it agreed that wastes that could not be removed from the HLW tanks could be disposed of in near-surface burial (like LLRW), even though the waste exceeded Class C concentration limits.'7 The NRC also adopted the same policy in determining the appropriate decommissioning criteria to be used for the West Valley Demonstration Project. In applying that policy, the Commission noted that, "[s]ince 1969, the Commission has recognized the concept of waste incidental to reprocessing, concluding that certain material that otherwise would be classified as HLW need not be disposed of as HLW and sent to a geologic repository because the residual radioactive 14 10 CFR § 61.7(b)(3).

15 "Intruder barrier means a sufficient depth of cover over the waste that inhibits contact with waste and helps to ensure that radiation exposures to an inadvertent intruder will meet the performance objectives set forth in this part, or engineered structures that provide equivalent protection to the inadvertent intruder." 10 CFR § 61.2.

16 10 CFR § 61.7(b)(5).

1_7 Letter from W.F. Kane, NRC, to R.J. Schepens, DOE, Savannah River Site High Level Waste Tank Closure: Classification of Residual Waste as Incidental (June 30, 2000).

5

contamination after decommissioning is sufficiently low as not to represent a hazard to the public health and safety."18 Thus, consistent with the accepted principle of waste averaging, these cases reiterate the conclusion that the concentration level alone of radioactive waste - even if greater than Class C - does not, by itself, preclude the safe disposal of the waste in licensed, near surface disposal facilities.

B.

The Inadvertent Intruder Scenario Does Not Apply to the Analysis of the Acceptability of Specific Waste Packages Having discussed how the intruder scenario is used, it is equally important to understand how it is not used. As noted above, the regulations do not require, either before or after disposal, that shippers or LLRW facilities consider the effect of a particular waste shipment on a hypothetical inadvertent intruder who, hundreds of years from now, may encounter the waste shipment. Rather, the intruder scenarios were used simply to identify the acceptable depth of disposal and/or intruder barriers for wastes received at a facility to protect the inadvertent intruder.

Again, the main purpose of intruder scenario analyses is to assist in the design and licensing of new LLRW facilities and the establishment of related institutional controls appropriate for the management of those radioactive materials that will persist in significant concentrations past closure.

Nonetheless, the intruder scenario is useful in this case to further demonstrate that the Millstone fuel rods, if assumed to be disposed of at either the Barnwell or Hanford LLRW facilities, would not pose any increased risk to an inadvertent intruder.

C.

General Description of Intruder Scenarios To evaluate the potential radiological effect of buried radioactive waste on an inadvertent intruder, the intruder analysis assumes (conservatively) that at some point after cessation of operations and the passage of an institutional control and monitoring period, institutional controls end.19 Of course, the likelihood of controls ceasing only 100 years after site closure is small.

After this period, the scenario theorizes that someone inadvertently enters the closed LLRW site for the purpose of making a home. The various activities involved in drilling a well, building a home, and engaging in agriculture are evaluated using conservative, hypothetical assumptions to create opportunities for contact with the buried waste that must each be analyzed 18 NRC Decommissioning Criteria for the West Valley Demonstration Project (M-32) at the West Valley Site, Final Policy Statement, 67 Federal Register 5003, 5009, February 1, 2002. (Emphasis added.)

19 NUREG/CR-4370, Update of Part 61 Impacts Analysis Methodology, Volume 1, Section 4.1.1.1, at 4-4, January 1986 (referred to as "NUREG-4370").

6

separately.2° These assumptions do not give credit for any institutional controls that may exist at the sites beyond the periods of time now planned for these disposal sites. In fact, at the Barnwell LLRW site there is no provision for removal of monitoring after the 100 year post institutional control and monitoring period. At the Hanford LLRW site, even 100 years after the site closes, there is no plan for DOE to withdraw its controls over the surrounding Hanford federal reservation.21 D.

The Intruder Drilling Scenario The Intruder Drilling scenario is the first of the four sub-analyses. The intruder drilling scenario assumes that an inadvertent intruder selects a site upon which to build a home and drills "a groundwater well for domestic use. The scenario assumes that a two-person drilling crew uses "a hydraulic (or mud rotary) drilling rig, or another rig appropriate for the region. The crew digs to a maximum depth of 200 feet.22 However, if the drill encounters a significant impediment such as large rocks or reinforced concrete, the crew is assumed to stop and re-position the drill a few feet away.- The scenario assumes that reinforced concrete barriers, typical of those in place at the Barnwell site, will remain effective for 500 years post closure of the facility. Thus, it is reasonable to assume that inadvertent intrusion will not occur for these 500 years.

After 500 years (assuming conservatively that the drill does not encounter resistance in the stable hardware wastes), the scenario assumes that the crew inadvertently drills through the waste, and causes some waste to come to the surface, mingled with soil and water (if using a hydraulic drilling technique), ending up in a drilling mud pit. The scenario assumes that the driller's helper is the individual most exposed because he/she is assumed to be standing adjacent to the mud pit and could receive direct gamma radiation from the mixture.-4 Because the waste will settle to the bottom of the mud pit, the source of the radiation will be shielded by a 2-3 ft thick layer of water.2-After use, the mud pit is filled with soil.26 This construct is detailed for the Barnwell and Hanford sites below.

2O Id.

21 See notes 12 and 13, su__r.

22 NUREG-4370, Section 4.2.1(4), at 4-18.

23 Id., Section 4.2.1(2), at 4-16.

24 Id Section 4.2.1(8), at 4-18.

25 Id., Section 4.2.1(7), at 4-18.

26 Id, Section 4.2.1(9), at 4-18.

7

1.

Barnwell At Bamwell, each of the shipments that possibly contained the Millstone fuel rods was placed in a burial trench at a depth of approximately 20-25 feet below land surface. These shipments contain irradiated hardware and similar materials that are stable, inherently insoluble, and not subject to degradation over longer periods of time. These wastes are contained in steel liners, which are placed in disposal cells. As discussed below, during the first 500 years after closure, an inadvertent intruder who by remote coincidence happened to drill for water in the exact location of the Millstone fuel rods would encounter multiple barriers, relocate, and receive no exposure from the shipments suspected of containing fuel rods.

To begin, a driller intruder during this period would encounter a number of layers that would not respond as natural strata to drilling and would require the driller to move.

Specifically, the sequence of materials that the driller would encounter from the top of the site to the top of the waste would include topsoil; a drainage layer; clay fill; a high density polyethylene membrane; a bentonite clay geotextile product; and a basement layer of clayey sand fill.7 The natural strata when drilled would appear differently and clearly would not include plastic and bentonite clay, for example. The drill rig would likely respond differently as well.

Moreover, even if this sequence of materials did not alert the driller, an intruder barrier would. An intruder barrier is a reinforced concrete barrier approximately 16 feet wide and 8 inches thick that runs past the ends and sides of the disposal cell. For Barnwell, intruder barriers have been placed such that their footprint extends well beyond the waste packages below, making is very unlikely that a drill would intercept any waste at all. On the top of this barrier the words "Radioactive Materials Do Not Dig" are imprinted periodically along its length, confirming the man-made nature of the barrier. A drilling rig that encounters this kind of barrier would not be able to penetrate the barrier. As recognized in applicable NRC guidance, "[i]t is assumed that drilling through reinforced concrete would be sufficiently difficult, or sufficiently out of the ordinary, that the drilling crew would stop and shift to a different drilling location.

No, or comparatively little, impacts from the drilling scenario would occur." 28 After 500 years, the analysis assumes conservatively that the concrete barriers are no longer there.29 Thus, the analysis assumes that the driller encounters the fuel rods and brings a portion of them up with the dirt into the mud pit. It is reasonable to assume that with a rotary drill of eight-inch maximum bore diameter, and assuming (conservatively) that the two fuel rods are located exactly side-by-side in the waste liner, the maximum fuel surfaced would be the equivalent of two, four-inch sections of the rods. This assumption is reasonable because rotary drilling is not likely to bring up pieces that are the full diameter of the rotary drill. Assuming that these segments settle to the bottom of the mud pit, the driller's assistant standing adjacent to 27 Letter from V. Ichimura to M.T. Ryan, March 28, 2002.

28 NUREG-4370, Section 4.2.1.1, at 4-21.

29 Id.

8

the pit for six hours would receive some small amount of direct gamma exposure from the fuel segments.

For the purpose of this conservative analysis, it is assumed that all the radioactive materials are contained in a point source in air and that the driller's helper is exposed at a distance of 1 meter. Under these conditions, the exposure rate from the gamma emitting radionuclides would be 0.27 mrem/hr and for a 6 hour6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months exposureL-the driller's helper would receive 0.16 mrem - a value far below the 500 mrem per year general dose rate limitation adopted by the NRC for an inadvertent intruder.L1 (The calculations supporting this result appear in Exhibit A-1 and A-2 in the Appendix to this report.) This very conservative estimate does not take credit for the shielding value of water or the fact that the pieces would more likely reside distributed over the bottom of the mud pit. Because the ceramic fuel pellets in the rod segments are insoluble and assumed to be reasonably intact in the mud pit, it is not likely that there would be any inhalation or ingestion exposure.L2 In short, the exposure to the driller's helper after 500 years is a very small fraction of the natural background exposure and would not pose any increased threat to the health and safety of the driller's helper.

2.

Hanford The well digging scenario described in NUREG-4370 assumes that the well digger will drill to a depth of 200 feet in search of water.3-At the Hanford site, groundwater is approximately and nominally 300 feet below the existing grade.-4 Accordingly, under NRC guidance, it is not reasonable to assume that an inadvertent intruder at the Hanford site would drill for water at all, given the depth of the water table.

30 Id., Section 4.2.1(5), at 4-18.

31 Final Environmental Impact Statement on 10 C.F.R. Part 61, "Licensing Requirements for Land Disposal of Radioactive Waste," November 1992, NUREG-0945, Vol. 2, at B 41; see also New England Coalition on Nuclear Pollution, Docket No. PRM-61-02, Denial of Petition for Rulemaking, Mar. 29, 1994 (rejecting a petitioner's request to change the intruder general dose limit to 100 mrem per year, and affirming the 500 mrem per year goal).

32 NUREG-4370, Section 4.2.1, at 4-16.

L3 Id Section 4.2.1(4), at 4-18.

L4 Department of Health, Draft Environmental Impact Statement ("DEIS"), Low Level Radioactive Waste Disposal Site, Richland, Washington, Appendix II, Radiological Risk Assessment, July 14, 2000, Section 4.2.2.2, at 107 ("The groundwater beneath the commercial LLRW disposal site begins at approximately the 300-foot depth and is located in the upper part of the silty sands and gravels of the Middle Member of the Ringold Formation.")

9

But, assuming conservatively, that the intruder was not aware of the depth of the water table and, nonetheless, continued drilling without detection, the calculated exposure would either be non-existent (before 500 years) or at a level that would not adversely affect his health or safety (after 500 years). As noted in the discussion of this scenario at Barnwell, drilling into the steel liner and irradiated hardware during the first 500 years would cause the driller to realize that he is not drilling in an acceptable location and he would move his rig." Additionally, drilling though a closure cap, regardless of the design selected, would alert the driller to the unusual conditions. Accordingly, he would receive no exposure.

After 500 years, assuming that the steel liner does not alert the driller, the exposure does not pose a threat. Drilling in the western United States is often performed using air rotary drilling, rather than wet mud drilling. This type of drilling creates the possibility that, in addition to the very small amount of direct exposure measured in the Barnwell scenario, a driller's helper could be exposed to some radioactivity through inhalation. To assess this contingency, it is assumed that:

1. A small piece of rod (one of the four inch pieces) is exhumed in about 1 kilogram (kg) of dirt.

2. 1% of this 1kg of dirt becomes dusty and that 1% of this dust is in the respirable particle size range. This is very conservative because the most likely situation is that the material would be covered by fresh cuttings as they are brought to the surface by the drill rig.

3. The driller's helper will be exposed for 10% of the six hours that the scenario is assumed to rmn3-6 without benefit of any respiratory protection. Dusts are not normally generated during all phases of rotary drilling, and any rod segment surfaced would be covered quickly by cuttings from the continued drilling.

If a driller's helper is so exposed, his internal dose would be 11.3 mrem (CEDE). (The calculations supporting this conclusion appear in Exhibits A-1 and A-3 in the Appendix to this report.) Again, this amount is a small fraction of the natural background exposure and would not pose any increased threat to the health and safety of a driller's helper. And as noted earlier, this dose falls far below the 500 mrem per year general dose limitation adopted by the NRC for an inadvertent intruder.-7 The external exposure in the case of air rotary drilling would be lower than the exposure estimated in the mud rotary case. It is estimated to be lower by a factor of 2 due to the smaller piece likely to be exhumed by air rotary drilling, or approximately 0.08 mrem.

3._55 NUREG-4370, Section 4.2.1.1, at 4-21.

36 Id., Section 4.2.1(5), at 4-18.

L7 See note 31, supra. See also DEIS, Low Level Radioactive Waste Disposal Site, Richland, Washington, August, 2000, Section 4.1.2, at 83 (applying the 500 mrem per year onsite intruder dose limit as a "guidance value.")

10

E.

The Intruder Construction Scenario The next sub-analysis for the hypothetical inadvertent intruder is the intruder construction scenario. In this phase, it is assumed that, having drilled a well, the intruder constructs a home on the LLRW site. The intruder is assumed to begin his home by excavating a basement 3 meters deep.-8 The intruder then constructs a basement 20m by 10m.L9 During this activity, it is theorized that the intruder comes into contact with waste and receives direct gamma exposure. This is the only reasonable route of exposure given that the fuel rods, if present, are stable and in shipment(s) of stable materials. In the analysis of this scenario, wastes disposed of below 10 meters are "assumed to be essentially precluded from access from the intruder construction scenario. For such waste the only applicable intrusion scenario is assumed to be the intruder-drilling scenario."'

For wastes buried below 5 meters, the impacts are assumed to be reduced by a factor of 10.41 Additionally, as with the intruder drilling scenario, the presence of reinforced concrete caps precludes contact with the waste for the first 500 years.

1.

Barnwell For Barnwell, this scenario does not apply as construction of homes with basements is quite atypical. Because of the lack of freezing conditions, the need to control termites, relatively flat terrain, relatively high rainfall and high humidity throughout the year, basements in that region of South Carolina are not practical. In fact, most homes are built with crawl spaces to aid in ventilation, insect, and moisture control and some homes are built as slab-on grade construction.

Even if the intruder construction scenario were applicable for Bamwell, the presence of reinforced concrete intruder barriers during the first 500 years would preclude radiation exposure. As discussed in the next section (intruder discovery scenario), a person building a home would stop upon encountering the concrete caps. 42 Even after 500 years, when credit is no longer taken for the intruder barriers, the intruder who happened to dig a basement over the Millstone shipments suspected of containing the fuel rods would still be alerted to the presence of something unusual because of the physical characteristics of the materials that would be exhumed. These materials would include remnants of the reinforced concrete intruder barriers, and other materials not natural in appearance to the near surface strata. Even if a basement were built in the Bamwell, South Carolina area, 38 NUREG-4370, Section 4.2.2, at 4-22.

R9 Id.

4.0 Id., Section 4.2.2.4, at 4-28.

4R Id.

4!2 Id., Section 4.2.3, at 4-29.

11

assuming the scenario depth of 3 meters (9.8 ft), the bottom of the basement would be well above (8.2 to 13.2 ft) the nominal depth of waste packages. The waste packages are typically 20 25 feet below land surface.

Additionally, "the intruder construction scenario is only applicable to situations in which the waste is sufficiently decomposed to resemble ordinary soil."'43 This same concept was noted in the intruder scenario analysis considered for disposal of the Trojan reactor vessel at Hanford.44 Similarly, contacting the rods and other irradiated material would be noticeable to the intruder and cause the intruder to recognize that he is in an unusual area requiring further investigation.

As discussed below, that investigation will lead to the discovery that he is attempting to construct a home on a closed LLRW facility. Thus, the intruder's exposure would be limited to that encountered in the discovery scenario.

2.

Hanford Three Millstone shipments were disposed at a minimum depth of 30 to 41 feet below the existing disposal cell final grade. Although capping for the Hanford site is not finalized at this point in time, closure capping will add additional depth. At a minimum, final capping will include 10 feet of natural soils above the existing grade of closed disposal trenches. The other closure options under consideration include a site soils cover, a thick homogenous cover, an enhanced asphalt cover, an enhanced synthetic cover, an enhanced bentonite cover, and a filled site alternative with a cover proposed by the licensee.-5 Regardless of the option chosen, the closure capping will provide added assurance that an inadvertent intruder would not surface the rods during hypothetical home construction activities.

For these reasons and, as documented for the disposal of the Trojan reactor vessel at Hanford, the intruder construction scenario does not pose any additional risk to the intruder, either before or after 500 years. As noted in the applicable NRC guidance, "Below ten meters, the waste is assumed to be essentially precluded from access from the intruder construction scenario."'6 As noted, home construction of any type (with or without a basement) is highly unlikely given the long-term institutional controls envisioned for the entire Hanford Reservation because of DOE waste remediation efforts. Additionally, most homes in the Hanford area do not have basements, further reducing the possibility that the rods could be surfaced during construction activities. Finally, as was described in the preceding Barnwell analysis, because of physical characteristics of the fuel rods, an intruder would likely be alerted to the presence of something unusual and take actions to limit his exposure. Given the ard conditions (well below L3 I.

Section 4.2.2.4, at 4-29.

L4 See Portland General Electric Company Response to NRC Request for Additional Information - Reactor Vessel Package, Attachment 1, at 7 (June 18, 1997).

!L5 DEIS, Section 4.1.2.1, at 84.

46 NUREG-4370, Section 4.2.2.4, at 4-28 (emphasis added).

12

10% soil moisture)47 that exist at Hanford, the steel liners, as well as the irradiated hardware and fuel rods, if any, will not degrade at the same rate as they would in a less ard environment. The Department of Health specifically noted the slow corrosion rate in such a dry disposal environment when it approved the disposal of the Trojan reactor vessel at Hanford.4-8 As a result, the retention of their physical integrity will provide a greater period of time in which the intruder, who somehow surfaced the items, will be alerted to the fact that he is conducting homebuilding activities into unnatural materials. As discussed below, that notice will cause him to relocate his activities, eliminating or minimizing any potential exposure. The Millstone fuel rods, if present at all, would not create any additional risk to the intruder constructor.

F.

The Intruder Discovery Scenario The Intruder Discovery Scenario is a modification of the intruder construction scenario.

As noted in NRC guidance:

The intruder-discovery scenario is similar to the intruder construction scenario except that the intruder is able to recognize that he is digging into very unusual soil immediately upon encountering the wastes, and consequently, gets exposed for a much smaller period. This scenario is applicable for stable waste forms which are disposed in a segregated manner from unstable waste forms. These stable waste forms are assumed to be recognizable as something out of the ordinary for a period of several hundred years after disposal.49 In this scenario, the intruder-discoverer is assumed to attempt the same homebuilding activities as the intruder constructorJL° However, the intruder discovery scenario assumes that, because of the physical characteristics of the waste, the intruder notices it and investigates. He consults records or other data, and learns that the site was used for LLRW.L Even if the waste alone is not easily discernable, grouted wastes and wastes disposed in reinforced concrete 47 Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site, PNNL-1 1800, Addendum 1 (September 1, 2001) (soil moisture ranged from 1.46% to 6.16%).

48 Washington State Department of Health, Technical Evaluation Report re: Trojan Reactor Vessel, Sept. 1998, at Section 3.2.2, at 10.

L9 NUREG-4370, Section 4.1.1.1, at 4-5.

50 Id., Section 4.2.3, at 4-29.

51 Id.

13

structures are assumed to be discoverable.12 The scenario assumes that the intruder's exposure time is limited to six hours.53

1.

Barnwell As noted earlier, the intruder discovery scenario assumes that the same activities occur as in the intruder construction scenario. At Barnwell, it is not credible to assume the intruder attempts to dig a basement at anytime either during or after the 500 year post-closure period.

Accordingly, he will not receive any exposure through either the intruder construction scenario or the intruder discovery scenario. Additionally, even if he did attempt to build a basement during the first 500 years, the intruder would discover the reinforced steel concrete intruder barriers well before encountering the rods and would not receive any exposure from the fuel rods. Finally, the depth of the buried material would prevent the intruder from encountering the rods, before or after 500 years.

2.

Hanford The analysis of this scenario for the Hanford site leads to the same result, albeit for different reasons. Even though, in reality, there are few basements in homes in the Hanford area, an inadvertent intruder who decides to dig a basement would not encounter the fuel rods. At Hanford, he would never encounter the fuel rods, with or without caps, at any time before or after 500 years because the liners are buried more than 10 meters deep. Accordingly, he would not discover or be exposed to the fuel rods.

G.

The Intruder Agriculture Scenario This is the last of the four sub-analyses that make up the inadvertent intruder scenario.

This variant assumes that, after the intruder has dug a well and built a home, he grows food in the soil.M The scenario assumes that construction brings wastes that appear like soils to the surface for agricultural purposes.L5 This scenario assumes that there are primary and secondary airborne and waterborne pathways of exposure associated with agricultural activities. It is typically the most complex and subject to high uncertainty in its ability to predict doses. Many of the assumptions are very conservative and unrealistic.

Unlike the other scenarios that consider one-time exposures of limited duration, this scenario considers longer periods of exposure. The scenario assumes that the intruder works at a job during the day away from his home and spends some time on weekends working in the 52 Id.

Q-Id.

L4 Id., Section 4.2.4, at 4-30.

L5 Id.

14

garden, growing food for half of his own consumption and spends nearly as much time outdoors in close proximity to his house as he spends at work (1700 hours0.0197 days 0.472 hours 0.00281 weeks 6.4685e-4 months versus 2000 hours0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months ).56 He is assumed to receive exposure through five possible pathways: (a) inhalation of contaminated dust due to tilling and other activities; (b) direct radiation from standing in the contaminated cloud; (c) consumption of food dusted by fall-out from the contaminated cloud; (d) consumption of food grown in the contaminated soil, as well as products from animals fed contaminated forage; and (e) direct radiation from the disposed waste.57

1.

Barnwell There are three principal reasons why the intruder agricultural scenario is not plausible at the Barnwell facility.

1. The type of waste that would be exhumed from a disposal cell or trench containing Class C waste cannot be used to grow food.

2. If surfaced at all, an agricultural intruder would recognize that these materials are not natural and would become an "intruder discoverer," who would curtail his activities after discovering the unusual, non-soil materials. As NRC guidance provides, "the intruder-discovery scenario preempts the... intruder-agriculture scenario.-58

3. It is much more likely that nearby-surface soils would be exhumed for agricultural purposes than soils excavated from deep below the surface. As such, the nearby surface soils are not likely to contain any radioactive wastes. If the surface soils were to contain any waste at all, it is more likely that these surface soils would contain Class A and Class B waste materials that are not distinguishable from soil.

It is least likely that stable wastes buried deeply would be exhumed for agricultural purposes.

None of the primary or secondary pathways of exposure are plausible because the wastes in the Millstone shipments are easily recognized as not being soil materials and could not be credibly used for agricultural activities. Food cannot be grown in these materials. It is simply not credible that either the irradiated hardware or fuel rods could degrade, be easily mixed with soils, and be used in any agricultural process. As recognized in NUREG-0782, and in the intruder analysis that accompanied the disposal of the Trojan reactor vessel, the "intruder scenarios analyzed contain one very large assumption - that the soil/waste mixture in which 56 Id Table 4.2, at 4-31.

L7 Id., Section 4.2.4, at 4-31.

58 Id Section 4.2.3, at 4-30. (Emphasis added.)

15

construction and agriculture takes place is more or less indistinguishable from dirt.",9 Neither the fuel rods nor the other irradiated hardware is or will be indistinguishable from dirt.

Finally, because basements are rarely used in homes near Barnwell, an intruder's activities would not surface the spent fuel rods and make them susceptible to any agricultural use. Even if an intruder conducted some other limited excavation, the intruder barrier caps and solid waste form would be detectable and cause him to move elsewhere. Even after 500 years, if he did limited excavation, the scenario assumes wastes buried below 5 meters are significantly less likely to contribute to exposure if undiscovered.ý-° For all of these reasons, it is not credible to assume that the intruder will have surfaced spent fuel rods during home construction that make their way into his garden.

2.

Hanford As discussed in the construction scenario, at Hanford, materials would not be exhumed due to depth of burial. Additionally, if the fuel rods and other irradiated material were somehow surfaced, the materials would nonetheless be recognizable as unnatural materials. In fact, given that the soil moisture content in the Hanford area is less than 10 %, the steel liners, as well as the stable waste forms, would retain their structural integrity to a far greater degree than if these items were in a less arid environment. All of the same reasons that make the intruder agricultural scenario inapplicable at Barnwell also make it inapplicable at Hanford. Finally, the likelihood that institutional controls will remain in place at the Hanford Reservation for a very long time period further supports the unrealistic nature of this hypothetical exposure scenario.

IV.

Conclusions Because of the small size of the fuel rods, there is an extremely low probability of encountering them during any intrusion, under any scenario, at either the Hanford or Barnwell facility. Indeed, the likelihood of striking the rods at the two facilities is 1 in 10 million at Hanford and 6 in 100 million at Barnwell.

Moreover, as demonstrated above, whether by the drilling, construction, discovery, or agriculture scenarios, the Millstone fuel rods, if present at all, would not create any greater risk of exposure to an inadvertent intruder than other materials already present and materials still being properly accepted by both sites.

Both facilities have disposed of radioactive materials, such as source materials, byproduct materials, and special nuclear materials, in significantly larger quantities from other sources.

The radioactive materials in the fuel rods are in a stable waste form, and disposed of in L9 Portland General Electric Company Response to NRC Request for Additional Information - Reactor Vessel Package, Attachment 1, at 7 (June 18, 1997) (quoting NUREG-0782).

60 NUREG-4370, Section 4.2.4.5, at 4-41.

16

shipments of other stable wastes, namely, irradiated hardware. These materials are inherently stable and are not subject to significant degradation over many centuries.

Although the fuel rods contain some limited quantities of specific radionuclides that cause the classification to exceed the Class C waste limits, the potential impacts of these radioactive materials are not properly assessed based on this classification alone. Consideration of concentrated sources is recognized and a variety of waste averaging procedures are in use to allow for small quantities of higher concentration wastes to be disposed.

Accordingly, whether considered from the point of view of any specific intruder scenario or whether considered from the perspective of the sites as a whole, the Millstone fuel rods, if present, would not create any unexpected or additional risk to inadvertent intruders or to members of the general public that are not already well managed by the plans and programs in place at both the Bamwell and Hanford disposal facilities.

17

APPENDIX Data and Calculations in Support of Evaluation of the Presence of Two Spent Fuel Rods on the Inadvertent Intruder A Supplement to Safety Analysis of Millstone Fuel Rods Potentially Disposed in Either the Barnwell, South Carolina or Hanford, Washington Commercial LLRW Disposal Site By Michael T. Ryan Ph.D., C.H.P.

CONTENTS Exhibit A-1 Exhibit A-2 Exhibit A-3 Radionuclides of Interest, Quantities and Activities Decay Corrected to 500 Years Calculation of External Dose to Driller's Helper Calculation of Internal Dose to Driller's Helper Appendix 2

Exhibit A-1 Radionuclides of Interest, Quantities and Activities Decay Corrected to 500 Years Exhibit A-I provides tables listing the radionuclides in the fuel rods. The first column in each table identifies the specific radionuclide. The second column gives the radioactive half-life of each radionuclide. The third column lists quantity of each radionuclide in a single fuel rod at 33 years post discharge from the reactor (fission products in Curies, actinides in Grams). The source of these data is Duke Engineering and Services Report, Rev. 1, dated June 6, 2001. They were previously referenced in Table 1 of the original Ryan Report.

The fourth column doubles numbers to account for two fuel rods. Finally, in the fifth column, the activity for each radionuclide has been decayed to 500 years post discharge from the reactor. As discussed in Sections IV.D.1 and IV.D.2 of the Supplemental Report, contact with the Millstone fuel rods by an inadvertent intruder at either the Barnwell or Hanford LLRW facility is implausible prior to 500 years post closure.

Table I (Fission Products)

Half-life Activity (Curies)

Activity (Curies)

(years) Single Rod at 33 years Two Rods at 33 years 1.530E+06 9.OOOE+01 2.130E+05 3.OOOE+01 1.OOOE+05 2.300E+06 2.912E+01 6.500E+04 6.500E+06 1.570E+07 7.600E+01 1.360E+01 1.235E+01 1.072E+01 1.333E+01 1.360E+01 8.800E+00 4.960E+00 2.770E+00 2.623E+00 2.900E+00 2.062E+00 1.009E+00 7.789E-01 6.847E-01 6.849E-01 6.630E-01 7.801 E-07 4.855E-06 3.490E-02 1.222E-01 2.192E+00 7.488E-01 1.588E-02 5.464E+01 7.843E-04 6.632E-04 4.265E+01 4.761 E-04 8.307E-05 3.392E-05 1.161 E-04 9.529E-03 9.354E-02 1.430E+00 3.409E-03 1.709E-03 2.152E-01 4.343E-02 4.315E-03 5.079E-02 1.211E-07 1.038E-03 7.708E-08 3.585E-10 3.869E-1 5 4.824E-16 3.706E-18 5.145E-17 5.169E+01 0.000E+00 0.OOOE+00 4.384E+00 1.498E+00 3.176E-02 1.093E+02 1.569E-03 1.326E-03 8.530E+01 9.522E-04 1.661 E-04 6.784E-05 2.322E-04 1.906E-02 1.871E-01 2.860E+00 6.818E-03 3.418E-03 4.304E-01 8.686E-02 8.630E-03 1.016E-01 2.422E-07 2.076E-03 1.542E-07 7.170E-10 7.738E-1 5 9.648E-16 7.412E-1 8 1.029E-16 1.034E+02 0.OOOE+00 0.000E+00 Activity (Curies)

Two Rods at 500 years 4.383E+00 4.106E-02 3.171E-02 2.252E-03 1.564E-03 1.326E-03 1.269E-03 9.475E-04 1.661 E-04 6.784E-05 3.282E-06 8.775E-1 3 7.744E-13 2.200E-1 3 1.938E-13 1.574E-13 4.558E-17 3.943E-30 1.530E-53 2.627E-55 8.090E-56 1.381E-71 6.741 E-147 2.344E-1 90 3.616E-220 5.447E-221 6.864E-230 O.OOOE+00 0.OOOE+00 0.OOOE+00 0.000E+00 Nuclide Fission Products ZR-93 SM-151 TC-99 CS-1 37 SN-126 CS-1 35 SR-90 SE-79 PD-107 1-129 SN-121M CD-113M H-3 KR-85 EU-152 NB-93M EU-154 EU-155 SB-125 PM-147 RH-102 CS-1 34 RU-1 06 CE-144 AG-110M SN-119M GD-153 AG-1 10 BA-137M BA-140 CD-115M Appendix 3

Half-life Activity (Curies)

Activity (Curies)

(years) Single Rod at 33 years Two Rods at 33 years Two Rods at 500 years Nuclide Fission Products CE-141 CS-136 EU-156 LA-140 NB-95 NB-95M ND-147 PM-146 PM-148 PM-148M PR-143 PR-144 PR-144M RB-86 RH- 03M RH-106 RU-103 SB-124 SB-126 SB-126M SN-123 SR-89 TB-160 TE-123M TE-125M TE-127 TE-127M TE-129 TE-129M XE-131M Y-90 Y-91 ZR-95 Total Nuclide Actinides U-234 U-235 U-236 U-238 NP-237 PU-238 PU-239 PU-240 PU-241 PU-242 AM-241 AM-243 Total Table 2 (Actinides)

Half-life Quantity (Grams)

Quantity (Grams)

(years) Single Rod at 33 Years Two Rods at 33 years 2.45E+05 7.620E-01 1.524E+00 7.04E+06 6.592E+01 1.318E+02 2.34E+07 6.199E+00 1.240E+01 4.47E+09 3.953E+03 7.906E+03 2.14E+06 3.513E-01 7.026E-01 8.77E+01 2.640E-02 5.280E-02 2.41 E+04 1.349E+01 2.698E+01 6.54E+03 2.594E+00 5.188E+00 1.44E+01 2.779E-01 5.558E-01 3.76E+05 1.297E-01 2.594E-01 4.32E+02 1.071E+00 2.142E+00 7.38E+03 7.835E-03 1.567E-02 8.904E-02 3.589E-02 4.162E-02 4.597E-03 9.630E-02 1.362E-02 3.008E-02 4.566E-05 1.471 E-02 1.132E-01 3.740E-02 3.288E-05 2.283E-07 5.112E-02 1.068E-04 9.481 E-07 1.078E-01 1.649E-01 3.397E-02 3.615E-05 3.540E-01 1.438E-01 7.230E+01 3.205E-01 1.589E-01 1.067E-03 2.986E-01 1.324E-04 9.205E-02 3.260E-02 7.306E-03 1.603E-01 1.753E-01 Quantity (Grams)

Two Rods at 500 years 1.522E+00 1.318E+02 1.240E+01 7.906E+03 7.025E-01 1.319E-03 2.662E+01 4.937E+00 9.602E-11 2.592E-01 1.013E+00 1.500E-02 8.085E+03 Appendix 0.OOOE+00 O.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 2.048E-05 0.OOOE+00 0.000E+00 0.000E+00 3.585E-10 4.302E-12 0.000E+00 0.OOOE+00 7.708E-08 0.000E+00 0.OOOE+00 1.098E-04 7.843E-04 5.124E-28 0.000E+00 0.OOOE+00 0.000E+00 1.05E-03 2.282E-32 2.282E-32 0.OOOE+00 0.000E+00 0.000E+00 4.266E+01 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.000E+00 0.OOOE+00 0.OOOE+00 O.000E+00 0.OOOE+00 0.000E+00 4.096E-05 0.000E+00 0.OOOE+00 0.OOOE+00 7.170E-10 8.604E-12 0.000E+00 0.OOOE+00 1.542E-07 0.000E+00 0.000E+00 2.196E-04 1.569E-03 1.025E-27 0.OOOE+00 0.OOOE+00 0.OOOE+00 2.106E-03 4.564E-32 4.564E-32 0.OOOE+00 0.000E+00 0.OOOE+00 8.532E+01 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.000E+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.000E+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.000E+00 0.000E+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 0.OOOE+00 4.463E+00 4

Exhibit A-2 Calculation of External Dose to Driller's Helper Exhibit 2 estimates the external radiation exposure to a driller's helper during mud rotary drilling from the gamma emitting radionuclides that remain at 500 years. The actinides are not included since their contribution to external dose is negligible. The contributions from the top seven radionuclides, by curie amount, are considered. Of these, four are gamma emitters and three are beta emitters.

The first column in Table 3 identifies the contributor to dose. The second column lists the activities in Ci from Table 1 in Exhibit A-1. The third column lists the activity of each contributor contained within two (2) four-inch segments of fuel rod, expressed in uCi. The fourth and fifth columns list the specific gamma ray constant for the gamma emitting radionuclides in SI units and conventional units, respectively. The final column gives the product of the specific gamma ray constant and the activity which yields the exposure rate at one meter in air from the hypothetical source that is assumed to exposure the driller's helper, expressed in, in mrem/hour.

The sum of these dose rates and total exposure for the scenario are listed at the bottom of this column.

The analysis includes the following assumptions:

"* Two (2) four-inch pieces of fuel rod are exhumed using wet drilling for the Bamwell case.

"* Each fuel rod is 13 ft 2 in. long, and 0.57 in. diameter.

"* The fraction of the total length of the two rods in these two pieces is calculated by dividing the total length of the pieces by the length of the two rods. This value is 0.025.

"* This fraction will be applied to calculate the amount of radioactive material in the segments theorized in the mud rotary drilling scenario.

"* The Driller's Helper stands one meter from the source for six hours.

"* The pieces of fuel rod are treated, conservatively, as a point source without shielding.

Appendix 5

Table 3 External Exposure to Driller's Helper Top Contributors by Curies remaining ZR-93 SM-1 51 TC-99 CS-1 37 SN-126 CS-135 SR-90 Activity in 2 Fuel uCi in Segments 2 Rods (Ci)

(4-in) Rod 4.383E+00 4.106E-02 3.171E-02 2.252E-03 1.564E-03 1.326E-03 1.269E-03 1.110E+05 1.039E+03 8.028E+02 5.700E+01 3.958E+01 3.358E+01 3.211E+01 Specific y constant mSv hr-I per MBq @ 1 meter beta emitter 2.44E-08 1.24E-10 1.03E-04 3.41 E-05 beta emitter beta emitter Specific y constant mRem hr-1 per uCi @ I meter 9.04E-08 4.60E-10 3.82E-04 1.26E-04 Exposure rate (mrem hr-1)

Total Exp to Driller's helper (mrem)

Appendix mrem hr-I at I meter 9.39E-05 3.69E-07 2.18E-02 4.99E-03 0.03 0.16 q

6

Exhibit A-3 Calculation of Internal Dose to Driller's Helper Table 4 calculates an estimate of internal exposure to a driller's helper for dry drilling methods such as air rotary drilling. Both fission products and actinides are included. The actinides are the significant contributors to this hypothetical exposure and the fission products are not significant.

The first column identifies the contributing nuclide. The second column lists the amounts of the important fission products (in Ci) and actinides (in grams). The third column lists half life for each radionuclide. The fourth column lists the decay-corrected activity of each of these radionuclides in the two fuel rods in Ci. These data are carried forward from Exhibit A-1.

The activity in the fuel rod segment hypothesized to be exhumable in this scenario is different due to the nature of the drilling method. It is a method that yields smaller fragments being brought to the surface from the drilling. One four-inch segment is assumed. The activity is calculated in the fifth column, expressed in uCi. The concentration of this quantity in the earth exhumed is presented in the sixth column, expressed in uCi/gm. The concentration that goes airborne and is assumed to be breathable as dust by the driller helper is calculated in the seventh column, expressed in uCi/cm3. The assumptions governing this calculation are listed below and discussed in Section IV.D.2 of the Supplemental Report.

The eighth column lists the Derived Air Concentration (DAC) values from 10 CFR 20 for each radionuclide. The ninth column calculates the DAC-hrs from which the exposure to the driller's helper is estimated. This value is calculated by the dividing the respirable concentration in the seventh column by the DAC in the eighth column and multiplying by the 0.6 hrs of exposure to the driller's helper in this scenario. The tenth and final column gives the Committed Effective Dose Equivalent (CEDE) to the driller's helper for each radionuclide. The total is provided at the bottom of this column.

This analysis includes the following assumptions:

"* Air-rotary drilling exhumes one (1) four-inch segment of fuel rod in 1kg of dirt.

"* Only a fraction (0.01) of the soil will become dust during drilling.

"* Only a fraction of that dust (0.01) will be in the respirable range.

"* The driller's helper is exposed for 10% of the six hours (0.6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months total) that occupies the volume of air.

Appendix 7

Table 4 Internal Exposure to Driller's Helper Fission Products ZR-93 SM-151 TC-99 CS-1 37 SN-126 CS-1 35 SR-90 Activity in uCi in 1 2 Fuel (4-in)

Rods Ci Segment 4.383E+00 5.548E+04 4.106E-02 5.197E+02 3.171E-02 4.014E+02 2.252E-03 2.850E+01 1.564E-03 1.979E+01 1.326E-03 1.679E+01 1.269E-03 1.606E+01 Actinides Grams in 2 Fuel Rods U-234 1.522E+00 U-235 1.318E+02 U-236 1.240E+01 U-238 7.906E+03 NP-237 7.025E-01 PU-238 1.319E-03 PU-239 2.662E+01 PU-240 4.938E+00 PU-241 9.602E-11 PU-242 2.592E-01 AM-241 1.013E+00 AM-243 1.500E-02 Half life Activity in uCi in I (years) 2 Fuel (4-in)

Rods uCi Segment 2.454E+05 9.477E+03 1.200E+02 7.038E+06 2.850E+04 3.608E+02 2.342E+07 8.021E+02 1.015E+01 4.468E+09 2.658E+03 3.365E+01 2.140E+06 4.953E+02 6.269E+00 8.774E+01 2.259E+04 2.860E+02 2.407E+04 1.655E+06 2.095E+04 6.537E+03 1.126E+06 1.425E+04 1.440E+01 9.893E-03 1.252E-04 3.763E+05 1.018E+03 1.288E+01 4.322E+02 3.477E+06 4.401E+04 7.380E+03 2.990E+03 3.785E+01 Concentration in exhumed dirt uCilgm 5.548E+01 5.197E-01 4.014E-01 2.850E-02 1.979E-02 1.679E-02 1.606E-02 Concentration in exhumed dirt uCi/gm 1.200E-01 3.608E-01 1.015E-02 3.365E-02 6.269E-03 2.860E-01 2.095E+01 1.425E+01 1.252E-07 1.288E-02 4.401 E+01 3.785E-02 Concentration (respirable)

(uCilcm3) 2.119E-11 1.985E-13 1.533E-13 1.089E-14 7.560E-1 5 6.412E-1 5 6.134E-15 Concentration (respirable)

(uCilcm3) 4.582E-14 1.378E-1 3 3.878E-1 5 1.285E-14 2.395E-1 5 1.092E-13 8.002E-12 5.442E-12 4.783E-20 4.921E-15 1.681E-11 1.446E-14 Derived Air Concentrations (DAC uCilcm3) 2.OOE-08 4.OOE-08 3.OOE-07 6.OOE-08 3.OOE-08 5.OOE-07 2.OOE-09 DAC Hours of Exposure 6.358E-04 2.978E-06 3.067E-07 1.089E-07 1.512E-07 7.695E-09 1.840E-06 Subtotal CEDE (Fission Products)

Derived Air Concentrations (DAC uCilcm3) 2.OOE-1 1 2.OOE-1 1 2.OOE-1 1 2.OOE-11 2.OOE-12 8.00E-12 7.OOE-12 7.OOE-12 3.OOE-10 7.OOE-12 3.OOE-12 3.OOE-12 DAC Hours of Exposure 1.375E-03 4.134E-03 1.163E-04 3.856E-04 7.184E-04 8.193E-03 6.859E-01 4.665E-01 9.567E-1 1 4.218E-04 3.362E+00 2.892E-03 Subtotal CEDE ( (Actinides)

Total CEDE Appendix CEDE (mrem) 1.589E-03 7.444E-06 7.666E-07 2.722E-07 3.780E-07 1.924E-08 4.600E-06 0.002 CEDE (mrem) 3.437E-03 1.034E-02 2.909E-04 9.640E-04 1.796E-03 2.048E-02 1.715E+00 1.166E+00 2.392E-1 0 1.054E-03 8.406E+00 7.229E-03 11.3 11.3 8

B18595, Response to Request for Additional Information Regarding Safety Analysis of Millstone Unit 1 Missing Fuel Rods

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B18595, Response to Request for Additional Information Regarding Safety Analysis of Millstone Unit 1 Missing Fuel Rods

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