ML20205K095

Forwards Brief Summary of NRC Review of Seabrook Emergency Planning Sensitivity Study & Current Working Draft of Table of Contents for Technical Evaluation Rept

ML20205K095
Person / Time
Site:	Seabrook
Issue date:	10/24/1986
From:	Long S Office of Nuclear Reactor Regulation
To:	Noonan V Office of Nuclear Reactor Regulation
Shared Package
ML20205J677	List: ML20205J673 ML20205J692 ML20205J718 ML20205J743 ML20205J760 ML20205J769 ML20205J781 ML20205J794 ML20205J820 ML20205J852 ML20205J894 ML20205K095 ML20205K127 ML20205K168 ML20205K183 ML20207A118 ML20207A145
References
FOIA-87-7 NUDOCS 8704010510
Download: ML20205K095 (3)

Text

, N i

+p* **%q#'g UNITED STATES 8 g NUCLEAR REGULATORY COMMISSION

'j WASHINGTON, D. C. 20555 D

'....** IO[E9 b _

MEMORANDUM FOR: Vincent S. Noonan, Director PWR Project Directorate No. 5 Division of PWR Licensing-A FROM: Steven M. Long, Project Manager PWR Project Directorate No. 5 Division of PWR Licensing-A

SUBJECT:

STATUS OF NRC REVIEW OF SEABRn0K EMERGENCY PLANNING SENSITIVITY STUDY ,

l A brief sucinary of the current status of our review effort is attached for your infonnation. We have not reached any conclusions at this time.

Also attached is a current working draft of the table of contents for the Brookhaven technical evaluation report. It shows the dates by which first draft of the various sections are expected to be produced at BNL.

LJ j Mbt ,/ _ t StevenM.Long,Projectyanager PWR Project Directorate No. 5 Division of PWR Licensing-A cc: H. Denton R. Vollmer T. Novak E. Rossi R. Sallard V. Renaroya C, Berlinger

[

] Milhoan F. Rosa G. Bagchi W. Lyon C. Tinkler D. Hackman S. Newberry E. Jordan D. Matthews T. Speis T. Murlev W. Kane " [02 // - 4' 7 - 7 A. Cerne C/GP 0704010510 070330 ppH I UI A

,P DH UHOLLYU7-7

.. \

9

• 10/24/86 STATUS OF NRC STAFF REVIEW 0F SEABROOK EMERGENCY Pl.ANNING SENSITIVITY STUDY .

l

, Within the Division of PWR I.icensing - A, the staff has formed a group to conduct a technical review of the Seabrook Emergenecy Planning Sensitivity Study. The primary objective is to evaluate the technical bases for the i public risk conclusions presented by the applicant. The review is being conducted as an audit type examination of the key technical bases in the report. The Brookhaven National I.aboratory is assisting the staff through a technical assistance contract. There are three key staff members in overall charge of the review, and there are at least twelve members of the i Brookhaven staff performing detailed examination tasks. IE is reviewing the 4 study's representation of the bases for emeroency planning reoutrements '

contained in NUREG-0396, i l'

The staff's review focuses on those areas where the study shows major risk reductions compared to the original PSA. These include the physical strength  !

l of the containment and the magnitude of the challenges to it. The " event V" '

i interfacing system 1.0CA through the RPR system is another area of risk reduction due to both the RPR vault design and enhanced modeling of the a sequence to account for the source term reduction due to the vault design, operator recovery actions, and the development of a data base for determining check valve failure rates. The staff is also considering other sequences i that lead to containment bypass, in particular, failure of steam generator j tubes due to overheating and preexisting breaches of containment integrity.

! The risks from operations at conditions other than full power will be considered as well.

4 The results of the staff's review will be used to reevaluate two risk j parameters presented in the applicant's report, the probability of early fatalities, and the probability of exceeding certain dose levels as a function of distance. The time delays before releases occur will also be 1 examined for differences in warning times between Seabrook and earlier studies. I i Members from the NRC staff and personnel from Brookhaven have visited the sitecto personally observe features pertinent to their review. These

! included the physical configurations of the containment, containment 1 j enclosures, fuel handling and auxiliary buildings, the area under the '

reactor vessel, the seal table, the RCS loop piping, the ECCS piping from

) the RWST to the RCS, and the containment penetrations for pipes, electrical

! conduits and purge lines. The control room, the emergency shutdown panel, i and the simulator were visited for the purpose of observing the indications and controls available to the operators for events of interest to the review.

j l

i I

.,,--,-,cw- -._-r n- ----,----n,-------ev,e-w-- - - , v.-- - , - - - - - - - -------,---------r--,----w----- -.~~--r-- , - - - - - - - - - , ~ - ,~

. . N l

. l

l i

i l.

) -

l s Several meetings, some lasting for two days, have been held with the applicant to exchange detailed technical information. The issues that were raised in these meetings have been documented in two Requests for Additional Infor1 nation, containing a total of 75 questions. The applicant has responded to many of these questions on the record and is working on the j remainder.

i The ACRS held a joint meeting of its subcommittees on Occupatfoal and Environmental Protection Systems and Severe (Class 91 Accidents on September

26. This meeting was requested by NRR to inform the ACRS of the technical aspects of the Seabrook study and the focus of the staff's review effort, 3'

and to obtain technical comments from the ACRS members for consideration during the staff's review. The subcommittee chairman reported to the full ACRS on October 10 and additional presentations by the public, staff and i' applicant were provided at that time. These meetings were for information .

purposes only. The ACRS will schedule additional meetings in November, when

! the staff review is expected to have resulted in some conclusions.

Staff review efforts are not complete. At this point, review of the contain- .

j ment strength and the estimation of the challenge are proceeding in  ;

i parallel, and the comparison of challenge to available capacity has not yet j been made. Review of event V has revealed areas of potential disagreement l

4 over the use of the check valve failure rate data and the source term credit for scrubbing of submerged plumes, and these issues are still being i evaluated. A discrepancy has also been identified in the isotopic concentration ratios of the release category which dominates the dose i

! probability vs distance curves, but the cor' rect release fractions have not i

i yet been identified or their effect calculated. Additional information has '

been obtained on the possibility of steam generator tube rupture due to j overheating, but this is not yet sufficient to either demonstrate that the phenomenon does not occur or to bound the probability to insignificant levels. IE has provided a written position paper on the criteria in NUREG-l 0396 that should be used for comparison of risk shown by the Seabrook study.

The t'arget date for production of a report containing conclusions reached by the staff's review efforts is mid-November.

i i

.i i

l i

l 4

9 +-- - --*-p--g-m..qt-we'y-w--y +m-m,y9gy3wir-p9w r -sp.ny pw--. y ,m i pmed-$w+-sy m '-wwy -- - - - - -+w e.w9 y--m.- ,--.g.m.,,e.,---g.--eem.m .,,iery., a,e--*-ee- g- . - - .--- -- + . - ,-me- .g.-y.-,,q