ML20207A254
| ML20207A254 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/22/1987 |
| From: | Harbour J, Hoyt H, Linenberger G Atomic Safety and Licensing Board Panel |
| To: | PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| References | |
| CON-#287-3222 82-471-02-OL, 82-471-2-OL, OL, NUDOCS 8704270043 | |
| Download: ML20207A254 (33) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION ATOMIC SAFETY AND LICENSING BOARD OfflCE D it at :f,,. y Before Administrative Judges:
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Helen F. Hoyt, Chairperson Gustave A. Linenberger, Jr.
Dr. Jerry Harbour g@e) APR 221987 In the Matter of
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Docket Nos. 50-443-0L
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50-444-OL PUBLIC SERVICE COMPANY
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(ASLBPNo. 82-471-02-OL) 0F NEW HAMPSHIRE, et al.
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(Offsite Emergency Planning)
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(Seabrook Station, Units 1 and 2)
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April 22, 1987 MEMORANDUM AND ORDER (Ruling on Applicants' Petition With Respect To Emergency Planning Zone In Excess of One Mile)
Background of the Applicants' Petition The Board has before it Applicants' Petition under 10 CFR 2.758 and 10 CFR 50.47(c) with Respect to the Regulations Requiring Planning for a Plume Exposure Pathway Emergency Planning Zone in Excess of a One-Mile Radius, filed December 18, 1986. Applicants' memorandum in support of their petition accompanied the petition. Attached to the certificate of service was a list of those documents Applicants relied on in their petition. The Board has attached this list as Appendix A.
On December 23, 1986, this Board ordered that any party to this proceeding could file a response in accordance with the provisions of 10 CFR 2.758(b). We affirmed the due date for responses in a Memorandum and Order dated January 7,1987 and again on January 21, 1987 in 870422
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response to a motion for extension filed by Massachusetts Attorney General. On January 27, 1987, the Board granted an extension to February 2,1987 to counsel for New England Coalition Nuclear Pollution (NECNP) and the NRC Staff due to unusual conditions in the Washington, D.C. area. Seacoast Anti-Pollution League (SAPL) asked for and received a one-day extension.
Opposition to Applicants' petition was timely filed by Intervenors:
i (1) Town of Hampton Memorandum in Opposition to Applicants' Petition to Reduce EPZ; (2) NECNP's 0pposition to Applicants' Petition under 10 CFR 2.758 and 10 CFR 50.47(c) for Waiver of Ten-Mile Emergency Planning Zone; (3) Seacoast Anti-Pollution League's Brief In Opposition to Applicants' Petition under 10 CFP. 2.758 and 10 CFR 50.47(c) for Reduction in the Size of the Scabrook Station Plume Exposure Pathway EPZ-and First Supplement dated January 29, 1987 and Second Supplement dated February 6,1987;(4) Town of Amesbury Response to Applicants' Petition under 10 CFR 2.758 and 10 CFR 50.47(c) with Respect to the Regulations Requiring Planning for a Plume Exposure Pathway Emergency Planning Zone in Excess of a One-Mile Radius; (5) Attorney General i
Shannon's Memorandum in Opposition to Applicants' Petition under 10 CFR 2.758 and 10 CFR 50.47(c) with Respect to the Regulations Requiring Planning for a Plume Exposure Fathway Emergency Planning Zone in Excess of a One-Mile Radius.
(Attached to the Attorney General's Memorandum i
were affidavits which are identified in our Appendix B); (6) Town of 1
1
f 3
l Kensington " Partial" response _; and (7) State of Maine's Memorandum in Opposition to Applicants' Petition to Reduce the Emeroency Planning Zone.
The State of New Hampshire filed its timely response in which the State did not take a position before the Board with respect to the Applicants' petition.
On March 26, 1987 there was filed with the Board Applicants' Motion to File a Reply to Massachusetts Response to Applicants' Petition under 10 CFR 2.758. NRC Staff opposed Applicants' Motion on April 10, 1987.
We deny Applicants' motion to file a reply to Massachusetts' response on the same grounds as that cited to us by the Staff. The provisions of 10 CFR 2.758 do not contemplate the filing of replies to responses and no good cause has been put forward by Applicants in this case to permit them to go beyond what the rule provides. Accordingly, the Applicants' reply has not been considered by this Board.
10 CFR 2.758 Section 2.758(a) provides that Commission rules may not be attacked in an adjudicatory proceeding concerning initial licensing, such as the operating license Applicants are seeking in this proceeding. Since the 1
Board records show only a three-line objection dated January 23, 1987. No complete response promised by February 3,1987 was received.
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4 rules under Part 50, specifically 50.47(c)(2), provide that a plume exposure pathway (EPZ) for nuclear power plants shall consist of an area of about 10 miles in radius, any reduction of the EPZ could only be permitted providing that a petitioner sustain an application for a waiver or an exception. The standard for determining if the petition is successful is whether the petitioning party has made a prima facie showing that the Commission rule would not serve the purpose for which the rule was adopted.
If there is a negative finding, no evidentiary proceeding will be permitted and the matter cannot be further considered by the Board.
The provisions of Section 2.758(b) are as follows:
(b) A party to an adjudicatory proceeding involving initial licensing... may petition that the application of a specified Commission rule or regulation be waived or an exception made for the particular proceeding. The sole ground for petition for waiver or exception shall be that special circumstances... are such that application of the rule or regulation (or provision thereof) would not... serve the purposes for which the rule or regulation was adopted. The petition shall be accompanied by an affidavit that identifies the specific aspect... as to which application of the l
rule or regulation... would not serve the purposes... and shall l
set forth with particularity the special circumstances alleged to justify the waiver or exception requested. Any other party may file a response thereto, by counter-affidavit or otherwise.
Applicants have also sought a grant of relief from the provisions l
of 50.47(c)(2) setting the 10-mile radius for emergency planning around the Seabrook nuclear plant.
In the event the Board determines that the permanent waiver or exemption under Section 2.758 is inappropriate, Applicants solicit the Board to grant relief under Section 50.47(c) by l
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5 applying the three criteria articulated in the rule.
In anticipation that a waiver in respect to emergency planning regulations may be granted under Section 50.47(c) only after a showing that Section 50.12 criteria have been satisfied, the Applicants have set out arguments meeting those criteria as well.
Discussion Pertinent to any discussion of the basis of our decision on Applicants' petition requires that we set forth the standard of what this Board considers is appropriate for a prima facie showing that Commission rule for a 10-mile EPZ can be waived or an exception made for this proceeding.
The prima facie showing standard was not defined in the 10 CFR 2.758(c) and only one Licensing Board has, by footnote, found that it is reasonable to equate " prima facie" showing with substantial showing.
Carolina Power & Light Company and North Carolina Eastern Municipal Power Agency (Shearon Harris Nuclear Power Plant) 21 NRC 410, 443 (1985). That Board did go on to say that this would mean that affidavits supporting a petition for waiver should present each element of the case for waiver in a persuasive manner and with adequate supporting facts from a qualified expert, where appropriate. To thi:
Board the difficulty here lies in accepting our colleague's explanation of what prima facie showing is with their labelling of this standard as being a substantial one. Were the standard such as to require the proof suggested by the use of term substantial, then there would be a need for
6 much more than " adequate supporting facts from a cualified expert." We believe that the label of substantial would require full, important, essential and considerable factual detail which is somewhat more than mere " adequate supporting facts."
It was against this background that the Board had to examine the use of an exemption of one of the more controversial public concerns relating to safety of the population around a nuclear power plant - that is, the evacuation of persons within only a one-mile radius in the event of a nuclear incident. We find little guidance in the cases before this Comission or the regulations. We would be less than candid if we did not express, albeit dicta, our belief that the girovisions of Section 2.758 were never intended to be used in deciding an issue of this magnitude.
The Appeal Board in Pacific Gas and Electric Company (Diablo Canyon Nuclear Power Plant, Units 1 and 2), ALAB-653, 16 NRC 55, 72 (1981) stated the standard with which we associate in this instance when it said that " prima facie evidence must be legally sufficient to establish a fact...unless disproved." We have applied this standard and find Applicants' petition does not meet the required prima facie showing
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needed to certify the matter to the Comission for final detennination.
Applicants in a response to joint Intervenors appeal of our order of January 7,1987 before the Appeal Board on January 27, 1987, at pages 9-12 has also stated what this Board has applied in determining the I
standard to be used in judging whether this petition passes muster.
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' Briefly stated, the Board has detennined that the prima facie showing standard is whether the petition with its accompanying affidavits as weighed against the responses of the parties, presents legally sufficient evidence to justify the waiver or exemption from the requirement of a 10-mile EPZ.
The provisions of this section provide that if an Applicant fails to meet any of the sixteen offsite emergency planning standards established in Section 50.47(b), the Applicant will have an opportunity to demonstrate the following:
(1) that deficiencies in the emergency plans are not significant for the plant; or (2) that adequate interim compensating activities have been or will be taken; or (3) that there are other compelling reasons to permit plant operation.
The Applicants have argued that the " deficiency" of a one-mile zone i
is not significant for the Seabrook plant because it has demonstrated that it is in compliance with the NUREG-0396 rationales that projected radiation doses would not exceed the Protective Action Guide levels beyond one mile. We believe that our discussion of Section 2.758 below has demonstrated the unacceptability of this argument.
The second alternative is that interim compensating activities have been or will be taken. Any discussion of such activities is premature to say the least. The Board is presently working toward resolving such
8 matters in the litigation of the NHRERP.
It would be inappropriate to grant the waiver on the as yet untested New Hampshire emergency plans.
The third alternative of " compelling reasons" is also rejected.
The Board has no difficulty with accepting Applicants' theory that Seabrook is a valuable energy resource. But that does not relieve the Board of its responsibility to make its finding that there is reasonable assurance that adequate protective measures can and will be taken in the event of a radiological emergency at this valuable energy resource. We also reject the argument that limiting a completed plant to low power operation is an unnecessary and unjustifiable economic burden. The regulations are quite clear - the plant must have an acceptable Radiological Emergency Response Plan (RERP) prior to going to full power. Other events occurring in this case make clear that the emergency plan for only one of the two states involved is ready for litigation on the issues of adequacy of various emergency preparedness provisions. The second State plan, filed by Applicants, has been circulated to the parties very recently.
In short, there is yet much emergency planning work to be done before we could determine that there were only minor cosmetic problems left which could be waived as insubstantial.
Applicants have not made their case here with any of the three criteria. We further note that Section 50.47(c) provides for waiver of planning standards set forth in Section 50.47(b). The requirement for the 10-mile emergency planning zone is set forth in Section 50.47(c)(2).
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9 Introduction To Technical Issues This discussion deals with the narrow question of whether Applicants have made a prima facie showing in support of their motion to reduce the size of the Seabrook plume exposure pathway emergency planning zone (PEPZ) to one mile. We have addressed this issue separately from the legal and regulatory sufficiency set forth above.
Applicants' motion was accompanied by technical documents and peer review testimonials purporting to provide a prima facie showing that a one mile PEPZ for the Seabrook Station is technically appropriate.
(See Appendix A).
Technical support for Applicants' motion was provided in the form of three documents:
1.
YAEC-1502, Licensing Aspects of the Seabrook Emergency Planning Zone Study, S. Lee and P. S. Littlefield, December 1985.
2.
PLG-0432, Seabrook Station Risk Management and Emergency Planning Study (RMEPS), Pickard, Lowe and Garrick, Inc.,
December 1985.
3.
PLG-0465, Seabrook Station Emergency Planning Sensitivity Study (EPSS), Pickard, Lowe and Garrick, Inc., April 1986.
These reports are summarily characterized as follows.
Item 1 presents the Yankee Atomic Electric Company's dose assessment results for the Seabrook Station that reflect not only the characteristics of the Seabrook Station but also the insights gained from numerous accident and source term studies since the publication of WASH-1400 and NUREG-0396.
Item 2 presents the results of a technical evaluation of emergency planning options and other risk management actions under consideration
-l 10 for Seabrook. These results include an update of the Seabrook Station ProbabilisticSafetyAssessment(SSPSA)preparedforPublicService Company of New Hampshire and Yankee Atomic Electric Company by Pickard, Lowe and Garrick, Inc. (PLG-0300, December 1983). As with Item 1, it includes more recent insights about source terms than were available for the SSPSA analysis.
Item 3 is most directly supportive of Applicants' motion in that it reverts to the source term methodology of WASH-1400 in performing a sensitivity study to help evaluate emergency planning options for Seabrook. Characterizing the source term methodology as extremely conservative, EPSS concludes that a PEPZ of no greater than one mile is appropriate for Seabrook.
The thrust of Applicants' technical discussion is that the design characteristics of Seabrook are such that accident analyses using WASH-1400 methodology--without taking account of advances in the understanding of source term behavior developed since the publication of WASH-1400--yield environmental releases of radiation at one mile from the plant site that have lower risk consequences than those deemed acceptable by NRC's Safety Goals. Additionally, Applicants state that said risk consequences are comparable to those considered by the authors of NUREG-0396 in concluding that an approximate ten mile PEPZ is appropriate for all light water plants. Hence, say Applicants, a one mile PEPZ is justified for Seabrook.
Other inputs reviewed by the Board include the following:
a Brookhaven National Laboratory (BNL) final report (March 1987) prepared for the NRC that performed sensitivity studies of those portions of
11 PLG-0465 found to be most influential in calculating Seabrook risk estimates; the response of the Comonwealth of Massachusetts to the Applicants' motion--in particular the affidavit of S. C. Sholly accompanying that response (Sholly Affidavit of 23 January 1987); the response of the Staff to Applicants' motion, which provided the affidavit of S. Newberry (Newberry Affidavit of 27 February 1987); the Review Comments of T. G. Theofanous prepared for the Staff regarding steam generator tube rupture (SGTR),12 January 1987; a Staff memorandum from Warren Lyon to Charles E. Rossi concerning SGTR events during severe accidents at Seabrook, 3 March 1987; and the coments of the New Hampshire Yankee Division of Public Service of New ifampshire transmitted by letter of January 20, 1987 to V. Nerses of the NRC Staff, concerning the BNL draft report A-3852 (predecessor of the BNL final report noted above).
Discussion Applicants' Case The materials submitted by Applicants in support of their motion requesting a reduction of the PEPZ from ten miles to one mile have been identified and characterized above. Whereas the materials provide a backdrop of infonnation of substantive value to formulating and critiquing the Seabrook emergency response plan, we address them here in the context of whether they offer sufficient technical input to warrant further consideration of Applicants' motion.
The Seabrook Station RMEPS (PLG-0432, December 1985) comprises a risk assessment that led Applicants to conclude that the total benefits
12 of evacuation of the populace around Seabrook are very small because the risk without evacuation is already very small and a one mile PEPZ is appropriate. The bases for this conclusion include the following:
The potential for early releases to the environment is substantially reduced because of the strength and structural integrity of the large, dry, reinforced concrete containment building; New data and engineering insights concerning accident sequences involving interfacing systems LOCA indicate an acceptable consequence for such events; A broad scope risk model is used in order to take account of Seabrook specific plant design and site characteristics and to take advantage of post WASH-1400 advances in data and modeling techniques; and, Post WASH-1400 advances in source term assessment are used.
The Seabrook Station EPSS (PLG-0465, April 1986) provides the results of a sensitivity analysis of the risk assessment results from i
RMEPS, but without source tem assessment advances, using, instead, WASH-1400 source term methodology. From PLG-0465, Applicants confirm I
their belief that a one mile PEPZ is appropriate for Seabrook, even without taking credit for recent reassessments of source term behavior, I
i.e., the conclusion of the RMEPS is insensitive to s'ource tem assumptions, as treated by Applicants.
The two documents just mentioned comprise the thrust of the i
technical support for Applicants' motion. YAEC-1502 presents a summary l
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13 of dose calculations made for Seabrook that is consistent with results of the broader scope PLG studies. However, we do not discuss YAEC-1502 here since its results are largely subsumed within the PLG documents.
An earlier full scope risk assessment analysis of Seabrook was performed by Pickard, Lowe and Garrick, Inc. for Public Service Company of New Hampshire and Yankee Atomic Electric Company ("Seabrook Station Probabilistic Safety Assessment" (SSPSA), PLG-0300, December 1983).
Building upon the SSPSA, the RMEPS (currently before us) updates the earlier assessment by invoking significant advancements involving the following:
Nature and magnitude of radioactive source term releases; Strencth of the Seabrook large, dry containment and implications of its integrity with respect to the timing and magnitude of source term releases; Progression of accident sequences for loss of coolant events outside of the containment.
Risk reduction options are examined in the perspective of this updated assessment. The significant results are sumarized as follows:
The acute health risk is very low in absolute tenns as well as in relation to any known standards of acceptability or safety goals.
Even under the assumption of no immediate protective actions, the acute health risk estimated for Seabrook Station is:
More than an order of magnitude less than that estimated in the SSPSA, which assumed a 10-mile evacuation distance.
More than an order of magnitude less than that estimated in WASH-1400, which assumed a 25-mile evacuation distance.
About two orders of magnitude less than the NRC safety goal for individual risk within one mile of the site.
Substantially less than the level of risk achieved with an EPZ distance of 10 miles as perceived in NUREG-0396.
14 Spatially located close to the plant site, with over 95%
located within two miles of the containment, and over 70%
within one mile.
The latent cancer risk is estimated to be:
Comparable to that estimated in the SSPSA and in WASH-1400.
More than a factor of 250 less than the NRC safety goal for societal risk within 50 miles of the site.
Insensitive to assumptions regarding evacuation because of the role of long-term exposures to low dose levels in the models used to estimate latent health effects.
Staff's Response The Staff requested that Brookhaven National Laboratory (BNL) undertake a review of the PLG reports ultimately submitted by Applicants in support of their motion. The BNL results have been published, first in a draft report (BNL A-3852, December 1986) and in a final report dated March 1987. We have reviewed both reports, which bear the same title " Technical Evaluation of the EPZ Sensitivity Study for Scabrook".
Our observation is that both reports deal with both of the PLG studies submitted by Applicants. We do not present our own sunmary of the BNL effort for the reason that Staff's critique of same is seen to be realistic and credible.
The Staff's response to Applicants' motion is contained in the affidavit of Newberry, which summarizes the Staff's current position as follows:
We believe that a more complete understanding of the Seabrook plant and risk assessment needs to be developed before a position can be taken on the risk assessment aspects of the petition. This is primarily due to the low probability estimates for early containment failure which are a cornerstone of the Applicants' petition. Unresolved questions remain from the BNL review of i
-l 15 PLG-0465 [BNL A-3852, Draft Report, December 1986] in the areas of containment loads (including the contribution to containment accident loads resulting from the direct containment heating phenomenon), induced steam generator tube rupture, and severe accidents at shutdown. We believe the BNL questions merit further investigation. Therefore, further detailed evaluation of accidents at shutdown and steam generator tube rupture is necessary.
Identification of a Seabrook specific containment event tree with Seabrook specific containment loads using the BNL structural capability estimates is also being considered. We also believe that further review of internal and external accident sequences in the SSPSA [an earlier risk assessment, PLG-0300, December 1983]
needs to be completed to consider the likelihood and uncertainty of early containment failure at Seabrook.
In addition to assessing the validity of Applicants' risk assessrent, the Staff will also be reviewing the Applicants' analysis of the consequence of design basis accidents at Seabrook.
In this regard, independent Staff consequence calculations are planned. The Staff also will be examining certain emergency-planning related issues, including the adaptability of emergency plans for the taking of ad hoc measures beyond one mile if necessary (the fourth rationale identified in Applicants' petition), and the rationales for having selected ten miles as the appropriate zone for the plume exposure pathway EPZ (Newberry Affidavit at 9-10).
The Staff's Newberry affidavit coments upon the major areas l
addressed by BNL, which are sumarized here:
Interfacing Systems LOCA (Bypassing containment) - BNL's most significant concern in this area relates to the initiation of such an l
event, it being primarily a function of valve failure rate. BNL estiraates a higher likelihood of failure than does PLG based upon valve failure rates judged to be more appropriate. However, BNL concludes that owing to credit for fission product scrubbing by coolant in the residual heat removal vault, this situation probably would not significantly change the risk profile assessment of PLG-0465.
16 Accidents During Shutdown - This item was not addressed by PLG-0465 but was assigned to BNL during its review.
In response to the BNL draft report, Applicants submitted additional information that pointed to the reduction of source term resulting from duration of shutdown as a mechanism that reduces accident significance. The BNL final report, published subsequent to the Newberry affidavit, concludes that the shutdown risk assessment is unacceptable as presently documented (BNL Final Report at 2-26).
Steam Generator Tube Rupture - This phenomenon involves the loss of steam generator tube integrity subsequent to the onset of a core melt accident. This could permit fission product release to the environment via steam generator relief valves, another potential example of containment bypass. While not reviewed in detail by BNL, this matter has been considered by the Staff and reviewed by Dr. Theofanous at Staff's request. Dr. Theofanous concludes that in the face of uncertainties of estimates and the recognition that not all tubes are in good-as-new condition, the effect of induced SGTR should not be neglected and prompt reactor coolant system depressurization should be given serious consideration.
(Review Comments of T. G. Theofanous, 12 January 1987, at 4-5).
Containment Isolation Failure - Neither the Staff nor BNL has reviewed this matter in detail. Applicants conclude that it has a small impact on risk; Staff concludes that fully closed purge and vent valves should provide reliable isolation under severe accident conditions (Newberry Affidavit at 6).
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17 Containment Integrity and Containment Loads - Given that the Seabrook containment is about 23% stronger than the Zion containment, BNL expects the probability of failure should be lower for Seabrook than for Zion.
BNL's analysis of the Seabrook containment leads it to conclude that failure due to gross leakage is not likely to occur at a pressure below 165 psig, including penetrations.
Seabrook specific containment loads were not derived by BNL. Based upon Zion loads previously analyzed by BNL, it estimates a low probability of early Seabrook containment failure but considers these estimates to be preliminary; BNL did not quantify the probability (Newberry Affidavit at 6-7).
Source Terms - BNL finds general consistency between fission product behavior in PLG-0465 and WASH-1400. BNL also finds that Applicants' justification of subcooling of coolant in the residual heat removal vault is reasonably supportive of the assumption noted above concerning thedecontaminationthatwillbeachieved(M.at7).
Consequence Modeling - Risk consequences for Seabrook are obtained in PLG-0465 through the use of the PLG "CRACIT" code whereas BNL used the "MACCS" code. Differences were found, but BNL believes that these differences are accounted for by differences in modeling techniques used in the two computer codes. BNL did not verify the risk of early fatalities reported by PLG-0465 but did note that the MACCS code would tend to predict more early fatalities than would CRACIT (Id. at 7-8).
For the most part, we consider that the BNL report has been appropriately characterized in the Staff's Newberry affidavit; hence we do not present a detailed assessment of it here. There is one matter,
18 however, that is addressed by BNL that perhaps deserves more emphasis than is given by Newberry. That has to do with accidents during shutdown. Because PLG-0465 does not address the subject of risk during shutdown, BNL made use of an NSAC report that specifically dealt wit),
this matter for the Zion PWR (Zion Nuclear Plant Residual Heal Removal PRA, NSAC-84, July 1985). NSAC-84 results show that the dominant core damage sequences during shutdown derive from loss of the residual heat removal system due to operator errors. Although BNL has found that extensive revisions to NSAC-84 are needed to correct deficiencies, these revisions (states BNL) tend to increase the frequency of core damage.
In response to Staff's request, Applicants presented additional I
information regarding shutdown accidents (PSNH Letter SBN-1225), dated 8
October 31, 1986, Response to Request for Additional Information (RAIs)
J. DeVincentis to S. M. Long). BNL states that the result of this analysis is inadequate, if not incorrect, and requires many changes (BNL Report at 2-18 through 2-22). [In fairness to the Staff, we note that the foregoing statement was found only in the BNL final report issued subsequent to the Newberry affidavit.]
As will be noted from the foregoing, the Newberry Affidavit seems not to take issue with the BNL report. Staff estimates that its full i
review of the merits of Applicants' motion can be completed by November 1987.
(Id. at 8).
Further insight into the Staff's thinking with respect to one of the above areas (SGTR) is contained in a report titled Seabrook Station Steam Generator Tube Response During Severe Accidents, January 27, 1987 l
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l 19 (Lyon Report). This report was transmitted by Staff Memorandum from W.
Lyon to C. E. Rossi, dated March 3, 1987.
It identifies a number of sub-areas in which work has been done, provides an assessment of that work, and makes recommendations for future work that may be needed to resolve the question of the seriousness of an SGTR event with respect to off-site risk consequences.
Owing to the high strength and large volume of the Seabrook containment, Applicants state that the containment has the capability to either significantly delay or to prevent the release of large amounts of radioactive ~ material during and following a severe accident involving core damage or core melt. Hence accident sequences that bypass the containment are of particular importance to the evaluation of the adequacy of Applicants' motion. One bypass potential involves a path l
between the reactor coolant system (RCS) and the environment via i
ruptured steam generator tubes. An SGTR event during a core melt accident while the RCS is at pressure offers the potential opportunity for a radioactive release through the steam generator relief valves, or through a rupture in a steam line outside the containment.
The Lyon Report says that an SGTR event is probably only of concern if the RCS is pressurized, but concludes that a formidable undertaking may be necessary to resolve the issue of whether such pressurization accompanied by tube failures presents an underestimated risk to the environment. Lyon characterizes Applicants' position on the matter as finding a small probability for the occurrence of the many SGTRs The required to produce a significantly large containment bypass.
20 Report acknowledges the position of Staff consultant Theofanous (as does Newberry, noted above) concerning the importance of RCS depressurization, but expresses the belief that the issue can be shown ultimately (albeit with considerable effort) not to contribute significantly to risk. The complexities of the problem are reviewed in considerable detail; the Report identifies several areas for which additional work must be done before Staff can reach a final conclusion.
We note parenthetically here that Applicants have provided to the parties and the Board a copy of their response to the Staff regarding their reactions to the BNL draft report, A-3852, enclosed with Applicants' letter to Victor Nerses (NYN-87-002), dated January 20, 1987. We have reviewed this response; it purports to set the record straight with respect to a variety of matters that Applicants believe has been improperly or unfairly dealt with by BNL. This response, alluded to in the Board Conclusions celow, does not materially alter our thinking.
Response of the Commonwealth of Massachusetts In support of its response to Applicants' motion, the Commonwealth submitted the affidavit of Steven C. Sholly and the joint affidavit of Sholly and Dr. Gordon R. Thompson. The former affidavit discusses numerous perceived faults associated with materials accompanying Applicants' motion. The thrust of each of these faults is summarized; the latter affidavit is not directly relevant to Applicants' motion.
Acts of Terrorism and Sabotage - It is noted that Applicants have 1.
not explicitly addressed such acts either in their motion or in
21 previously submitted accident analysis submittals, since worst-case accidents can be avoided or accommodated without regard to how initiated. The point is made that the analyses of accidents provide a blueprint for defeating plant protective measures on a detailed, plant-specific basis. The fact that history provides little precedence for concern is no basis for apathy about what the future may bring.
2.
Event V Modeling - Event V is the WASH-1400 analog of a LOCA (loss of coolant accident) initiated by the failure of valves separating the reactor coolant system from the RHR (residual heat removal) system.
Event V is also referred to as an interfacing LOCA event; the affidavit says that steam generator tube rupture (SGTR) is ano'ther example of this class of sequences. Affiant states the belief that the frequency of occurrence of event V sequences is significantly higher than estimated by Applicants. Over reliance on Bayesian methodology results and on prompt and proper operator actions are cited as bases for this belief.
3.
SGTR Scenarios - Two parts of the affidavit that treat steam generator accidents are combined here.
Frequencies of various accident scenarios are discussed along with impacts of station blackout assumptions. The consequences of updated source term considerations are imposed, leading affiant to conclude that there is the potential for more serious risk consequences than postulated by Applicants.
4.
Seismic Sequences - Affiant states that seismic events involving large ground accelerations (initial event, perhaps followed by strong aftershocks) can degrade the efficacy of emergency plan implementation, increase the likelihood of earlier than expected containment failure, m
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22 and degrade operator perfomance. Affiant believes that a more detailed review of such matters than currently exists is necessary to assess seismic event impacts.
5.
High Pressure Core Melt Modeling - Affiant cites Sandia experimental studies for the proposition that Applicants' characterization of the behavior of core debris efected from the reactor vessel may be incorrect.
In particular, he states that dissolved gases in the core melt and the production of aerosols by the melt ejection 1
process can lead to containment pressurization and direct containment heating, presenting the potential for early containment failure and higher than anticipated radioactivity release, matters that-Applicants have not adequately considered. Affiant expresses his disagreement with Applicants and BNL that such phenomena cannot cause the Seabrook containment to fail or at worst to fail at a very low probability.
6.
Containment Pressure Failure - In essence, the affidavit builds upon the above considerations and leads to the possibility that containment integrity may not be adequate for containment pressure loads derived from phenomena noted in the above item.
7.
Steam Explosions - Work done by others (e.g., UKAEA and Sandia) convinces affiant that there is substantial uncertainty over the probability of containment failure due to in-vessel steam explosions (temed an alpha-mode failure). This is taken to indicate that an alpha-mode failure cannot be ignored in the context of PEPZ distances.
23 8.
Iodine Behavior - Two parts of the affidavit dealing with fodine are combined in this summary. Affiant suggests that the following possibilities concerning iodine behavior can be important:
The formation of volatile, organic iodine within the containment might impact environmental releases depending upon containment spray behavior and integrity of the containment itself; Saadia experiments indicate the possibility that cesium fodide (the chemical form dealt with by Applicants in their accident analyses) may dissociate into elemental iodine and permit HI and HOI to dominate under the influence of gamma radiation in the pressure vessel - containment envelope and of hydrogen burns, thus behaving quite differently than CsI; and, Late containment failures can provide an opportunity for tellurium-132 (78 hour9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br /> half-life) to decay to iodine-132 (2.3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> half-life) leading to the possibility of gamma radiation exposure not being adequately considered.
9.
Aerosol Behavior - Citing no bases to suppart his thesis, affiant postulates that deposited fission product aerosols might as the result of chemical or mechanical disturbances re-evolve for release to the environment, and give rise to higher than anticipated source term
/
estimates.
- 10. Accidents During Shutdown - Citing prior assessments of this category of accident as being restricted to internal events leading to a shutdown accident, affiant states that external events, especially earthquakes, should be considered for cold shutdown accidents, when
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24 4
containment isolation is not required. A study of the Sequoyah plant by Science Applications, Inc., is criticized for not having considered quakes larger than the safe shutdown earthquake. Affiant states that full consideration of seismic initiating events is required in order to perform a complete cold shutdown risk analysis.
- 11. De-Inerting Burns - The affidavit states that when A/C power and/or containment sprays are appropriately recovered during an accident sequence, Applicants treat the accident as being benignly terminated.
l The potential for high concentrations of oxygen and hydrogen in the containment if containment spray is recovered several hours after reactor vessel failure is said not to have been considered by Applicants. Thus, affiant states that there is the potential for a hydrogen burn; and if containment integrity is not maintained indefinitely, risks could be understated.
- 12. Accident Behavior of Secondary Containment - Characterizing the Seabrook containment enclosure (secondary containment) as having a low pressure capacity, affiant states that this enclosure offers little radioactivity mitigation from a severe accident in which primary containment integrity is lost. At best, it might offer the advantage of a more elevated release point than would otherwise be the case. Lacking a steel liner such as exists in the primary containment and having a low pressure capability give the secondary containment little merit during severe accidents.
Peer Review - Affiant states that in the circumstances under which l
13.
it was perforned, it was impossible for the peer review group to have l
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25 performed adequately in the face of such a complexity of considerations and time constraints before them. He also questions the independence of the reviewers. Affiant further notes that despite the importance placed on containment strength by Applicants, none of the reviewers is a l.
structural engineer.
- 14. Consequence Modeling - Affiant devotes two separate discussions to the thesis that the risk consequences of a severe accident at Seabrook should not ignore the differences (for the same accident sequence) that can arise from differing assumptions made for different consequence l
models. Specific references are made to the various codes employed in iustifying the reduction of the Seabrook PEPZ, with emphasis upon the extreme care that must be exercised in intercomparing results.
Affiant Sholly concludes that the PEPZ designation of ten miles from NUREG-0396 was set in the face of numerous uncertainties and that Applicants' motion does not carry the day so far as justifying a significant reduction of that distance for Seabrook, because of considerations such as discussed above and the numerous uncertainties involved here also.
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Board Conclusions Preface Prior to our review of the Applicants' motion and the responses thereto, the Board raises the following considerations:
With respect to the TMI-2 accident, from the 1980 Rogovin report it appears that plant operating personnel could have
'essened the severity of accident consequences by more rigidly
26 adhering to proper procedures, and by being better prepared to interpret the significance of off-normal plant conditions; Numerous incidents recently reported in NRC Information Notices regarding licensed nuclear power plants attest to the thesis that there are instances of hardware components having safety significance that have not on random demand performed in accordance with the design intent for those components (check valves, motor operated valves, incorrect status readout in control room and faulty instrument air supply are typical examples);
Although Applicants state that advancements in the understanding of source term behavior have not been taken into account, there are prior source term reassessment analyses that cause us to question whether such an omission represents a potential for error in the analyses of accident consequences and containment performance that might ultimately yield more severe than anticipated environmental consequences (fission product behavior and transport within the reactor-containment envelope, core-concrete interactions and aerosol formation and behavior are a few of the phenomena about which possibly significant uncertainties remain);
It would be instructive to know whether, at TMI-2, after-the-fact evaluations of containment performance and off-site risks would lead to the conclusion that a one mile PEPZ for THI-2
27 would have been equally as appropriate, technically, as Applicants conclude for Seabrook.
Our subsequent review of Applicants' motion has uncovered little basis for confidence that measures have been or will be taken to assure that no larger-than-anticipated environmental consequences will result from the first three of the above considerations. Without more specific information from Applicants than is currently before us, the above considerations place in question the sufficiency of Applicants' justification for a reduction of the PEPZ to one mile.
Conclusions The providing of an in-depth and definitive assessment of the sufficiency of the technical merits of the materials Applicants have provided in support of their motion to reduce the radius of the Seabrook Station PEPZ to one mile is a formidable and complex task. The Board has not attempted a g novo review of these matters for such would be beyond the resources of time, personnel, and computational assistance available to us. Additionally, to do so would requiro significantly more in-depth information than is currently before us in the way of input assumptions, code and model details, and the actual computations leading to many results whose derivations are only sumarized. Rather, we have reviewed with considerable care the Applicants' materials including several references contained therein, and the responses of others to those materials. The purpose of this review has been to gain f
a perspective about the technical merit of Applicants' justification for reducing the PEPZ and the depth, completeness and credibility of that
28 justification. As the Lyon Report (discussed above) acknowledges, Applicants have undertaken a very comprehensive investigation of nuclear power plant accidents and risk consequences specific to the Seabrook plant and site. We have reached the same conclusion.
We have seen no basis that would cause us to conclude that there are errors in the results proffered by Appifcants in support of their motion. On the contrary, we believe that Applicants have made a good faith effort to support their motion. Nevertheless, there are a number of areas wherein it appears that Applicants have not presented full and complete results sufficient to inspire confidence that their motion deserves further consideration at this time. We identify several of these now, in no particular order of priority or importance.
Containment Strength - Superior strength of the Seabrook containment is a major factor underlying Applicants' position. Given that the design strength is as Applicants conclude it to be, the as-built strength may be less than designed. The Baard is unable to discover a basis for believing that this is not the case.
Source Term Behavior - post WASH-1400 reassessments of radioactivity behavior make it unclear that the use of WASH-1400 source term methodology is categorically conservative. For example, iodine behavior, fission product re-evolution potential, aerosol formation and transport may be influenced by the specifics of accident sequences, associated chemical dynamics and the influence of radiation fields. We are not aware that such matters have been given adequate consideration.
_-a.
29 Operator Reliability - Numerous Seabrook accident sequences have identified certain plant operator actions to be taken to mitigate the consequences of an accident in progress and in several instances Applicants state that such actions are being or have been incorporated into plant operating procedures. Absent an understanding of how well operator training prepares operators to recognize off-normal plant conditions, to assess the urgency of following special procedures and to execute the proper actions, the Board is left in doubt that accident mitigation requiring appropriately prompt and/or proper operator i
response will always be safely carried out.
Equipment Malfunction - Included here is the possibility that certain equipment, although performing as desired, will not have its status correctly displayed to operators. The possibility that certain equipment will not perform its intended function upon emergency or random demand cannot be overlooked. This is not to say that Applicants have overlooked such matters. However, a detailed analysis of preoperational and in-service testing and maintenance to minimize or prevent such occurrences is not before us for evaluation.
[
Accident Analyses - Apart from the preceding comments, the Newberry i
affidavit, the Lyon Report and the Sholly Affidavit discuss a variety of l
accident sequence analyses and their resulting risk consequences that l
have been treated in a manner that raises questions about the comparability of input assumptions, differing computational approaches l
and the propagation of uncertainties associated with risk results.
In Applicants' response to the BNL draft report A-3852 (submitted as an i
f
30 enclosure to NYN-87-002, a letter from PSNH to V. Nerses of the NRC Staff, January 20,1987) Applicants explain that many of these matters, at least as commented upon by Brookhaven, reflect variances of perspective, questionable selections of experience with component failures, imperfect understanding of details of the Seabrook design, etc. When placed in proper context, say Applicants, the BNL objections lose their significance.
Accidents During Shutdown - In discussing this topic, the Newberry affidavit notes Applicants' assertion that the time f aterval between i
shutdown and an accident during shutdown provides time for the decay of fission products, thus reducing the decay heat generation in the core.
While this is a valid observation, the Board has not found where consideration has been given to the possibility that an accident during shutdown might restore the fission product inventory to a level unacceptable in terms of risk consequences.
I SGTR Events - Newberry, Theofanus and Lyon offer a consensus of concerns regarding this matter that has not adequately, as yet, been laid to rest by Applicants.
The foregoing items provide a sampling of topics that causes this Board to conclude that it would be premature to recommend to the Commission, at this time, that further consideration should be given to Applicants' motion. We do not take a position that a one mile PEPZ for the Seabrook Station is unjustifiable; only that Applicants and Staff need more time to determine convincingly whether it is. This is especially important since the Seabrook Station has not yet operated and 1
31 its. operational and maintenance organizations have had no opportunity to establish a team effort track record. Accordingly, we conclude that Applicants' instant petition does not provide a prima facie showing on its technical merits.
THE ATOMIC SAFETY AND LICENS G BOARD h
Helen F. Hoyt, Chairpers Administrativ udge Qg p
A Ww Gustave A. Linen)ergdr, Jr.
v
@ inistrative Judge M
Administr/ Harbour DrVJerry ative Judge Dated at Bethesda, Maryland this 22nd day of April 1987.
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Appendix A (Documents Relied Upon By Applicants) 1.
Seabrook Station Risk Management and Emergency Planning Study, PLG-0432 (1985).
2.
Seabrook Station Emergency Planning Sensitivity Study (SSEPSS).
3.
Affidavit of Karl N. Fleming.
4.
Affidavit of Dr. Alfred Torri.
5.
Affidavit of Robert J. Lutz.
6.
Affidavit of Dr. Robert E. Henry.
7.
Affidavit of Keith Woodard, 8.
Letter of Robert J. Budnitz of November 9,1985 to New Hampshire Yankee Division of Public Service Company of New Hampshire.
9.
Letter of Dr. Robert J. Budnitz of January 17, 1986 to New Hampshire Yankee Division of Public Service Company of New Hampshire.
- 10. Affidavit of Dr. Robert J. Budnitz.
- 11. Affidavit of Dr. David C. Aldrich.
- 12. Affidavit of Dr. Joseph M. Hendrie.
- 13. Affidavit of Dr. Norman C. Rasmussen.
- 14. Affidavit of Dr. Rboert L. Ritzman.
- 15. Affidavit of Dr. William R. Stratton.
- 16. Affidavit of Dr. Richard Wilson.
- 17. Licensing Aspects of the Seabrook Emergency Planning Zone Study, YAEC-1502, Yankee Atomic Electric Co. (1985).
- 18. Affidavit of Dr. Shengdar Lee.
- 19. Affidavit of Peter S. Littlefield.
- 20. Affidavit of John G. Robinson.
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Q Appendix 8
. (Documents Relied Upon By Commonwealth of Massachusetts) 1.
Affidavit of Steven C. Sholly.
2.
Affidavit of Gordon Thompson. - Resume for Gordon Thompson. - Some Comments on Recent Studies Sponsored By Public Service Company of New Hampshire, Regarding Planning at the Seabrook Nuclear Plant. - The Source Term Debate - A Report By The Union of Concerned Scientists.
3.
Affidavit of Dr. Joel R. Primack.
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