ML19325E586

Responds to Generic Ltr 88-20,Suppl 1, Individual Plant Exam for Severe Accident Vulnerabilities. Licensee Will Submit Rept Describing Plant Exam by Mar 1991 & Will Include cross-ref to Sections of Rept Defined in NUREG-1335

ML19325E586
Person / Time
Site:	Seabrook
Issue date:	11/01/1989
From:	Feigenbaum T PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-1335, RTR-NUREG-CR-4452, RTR-NUREG-CR-4540 GL-88-20, NYN-89136, NUDOCS 8911080055
Download: ML19325E586 (5)

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,1 New Hampshire , Tod C. .:..e - x a Senior Vice President and i Chieloperating C6cer l NYN-89136  !

l November 1, 1989 J United. States Nuclear Regulatory Consnission Washington, DC 20555  ;

Attention: Document Control Desk i

References (a) Facility Operating License No. NPF-67 Docket No. 50 443  !

(b) USNRC Generic Letter 88-20, dated November 23, 1989, I

' Individual Plant Examination for Severe Accident Vulnerabilities'  ;

(c) Supplement 1 to USNRC Generic Letter 88-20, dated August i 29, 1989, ' Individual Plant Examination for Severe i Accident Vulnerabilities' I Subjects Response to Generic Letter 88-20

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Gentlemen:

In response to Reference (b), this letter provides information l pertaining'to the New Hampshire Yankee (NHY) Program for performing the  ;

Individual Plant Examination (IPE) for Seabrook Station. In summary, NNY j has already fulfilled the intent of Generic Letter 88-20 to ' perform a {

systematic examination to identify any plant-specific vulnerabilities to }

severe accidents *.

Station Probabilistic ThishasbeenaccomplishedbycompletionoftheSeabrook

Safety Assessment (SSPSA) and the establishment of an l

' ongoing risk management process.

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The SSPSA was completed in 1983 by a team of offsite contractors led I by Pickard, Lowe and Garrick, Inc., with significant input from NHY and i Yankee Atomic Electric Company (YAEC). The SSPSA is a full-scope, level i three probabilistic safety assessment applicable specifically to Seabrook

• Station. It was submitted to NRC for information on January 30, 1984.2 NRC i l reviews of the SSPSA are documented in two NRC reports: NUREG/CR-44523 and ppm NUREG/CR-4540.4 }

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n The risk management process has two principal objectives. The first i

3. objective is to maintain an updated probabilistic safety assessment for '

l ( [ Seabrook Station. Since completion of the SSPSA in 1983, many subject- >

it ;" specific updates of the SSPSA have been performed and documented. In 1986,  !

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a comprehensive update of all aspects of the SSPSA was performed and i l

D documented. The 1989 comprehensive update of the SSPSA is scheduled to be l l completed and documented by March 31, 1990. Updates consider, as r l appropriate, changes in plant design and operation and incorporate enhancements to the computer model employed to perform the analyses.

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i New Hampshire Yonkee Division of Public Service Company of New Hampshire pal P.O. Box 300

• Seabrook, NH 03874

• Telephone (603) 474 9521 g

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i' United States Nuclear Regulatory Commission November 1, 1989 Attention: Document Control Desk Page 2 ,

l Additionally, an in-depth study of the shutdown modes of operation 5 at i Seabrook Station, has effectively increased the scope of the SSPSA. j The second objective of the risk management process is to apply '

probabilistic safety assessment information to proposed station design changes and improvements in methods of operation. A formal method,  !

documented in NHY prccadures, implements this objective by requiring that significant plant changes are evaluated for their impact on the probabilistic -1 safety assessment. The results of the evaluation can indicate the need to i update the probabilistic safety assessment and/or revise the proposed change  !

to enhance safety. In addition to reviews of proposed changes. NNY has also applied probabilistic safety assessment information to Technical Specification .

i optimization 7and emergency planning strategies.8,9,10 Personnel experienced in probabilistic risk assessment methods onsite and at YAEC implement the risk '

management process for Seabrook Station. l The Individual Plant Examination (IPE) for severe accident vulnera- ,

bilities at Seabrook Station will consist of the previously submitted SSPSA ~

and associated studies, plus the 1989 update described above. The 23PSA was,  :

and thus the IPE will be, a full-scope, level three probabilistic safety l assessment. As a full-scope probabilistic safety assessment, the SSPSA l included consideration of both internal transients and external hazardo as '

l initiating events that could potentially cause a severe accident. As a level l three probabilistic safety assessment, the SSPSA evaluates potential accident

• sequences beginning with the initiating event and including plant operator response, potential core damage, fission product release and offsite .

consequences.

New Hampshire Yankee will submit a report describing the IPE by March 1, 1991. This report will sunanarize the SSPSA, its associated studies and the ,

current comprehensive update. The report will include a cross-reference to ,

relate sections of the report to the corresponding format defined in NUREG- ^

l 1335. ,

Enclosure 1 lists additional references associated with the SSPSA.

l If you have any questions on this matter, please contact Mr. Geoffrey i Kingston at (603) 474-9521, extension 3371.

Sincerely yours, hlb Ted C. Feigenbaum ,

, United States Nuclear Regulatory Commission November 1, 1989 Attention: Document Control Desk Page 3 cci Mr. V1111am T. Russell Regional Administrator United States Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406

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Mr. Victor Herses, Project Manager Project Directorate I-3 United States Nuclear Regulatory Conunission Diviston of Reactor Projects Washington, DC 20555 Mr. Dave Modeon Nuclear Management and Resources Council 1776 Eye Street, N.W.

Suite 300 Washington, DC 20006-2496 Mr. Antone C. Cerne NRC Senior Resident Inspector P. O. Box 1149 Seabrook, NH 03874 I

STATE OF NEW HAMPSHIRE Rockingham, ss. November 1, 1989 l Then personally appeared before me, the above named Ted C. Feigenbaum who, being duly sworri, did state that he is Senior Vice President and Chief  ;

Operating Officer of New Hampshire Yankee, that he is duly authorized to i execute and file the foregoing information in the name and on the behalf of l New Hampshire Yankee, and that the statements therein are true to be the  ;

best of his knowledge and belief. i OMu O S M e wo .,  !

Beverly E.dilloway, Notary Pjblic  !

Hy Commission Expires: March 6, 1990 i

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New Hampshire Yankee [

November 1, 1989 l t,

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ENCLOSURE 1 TO NYN-89136 i

I RESPONSE TO GENERIC LETTER 88-20  ;

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e-ENCLOSURE 1 TO NYN-89136 ADDITIONAL REFERENCES ASSOCIATED VITH THE SSPSA

1. Pickard, Lowe and Garrick Inc., 'Seabrook Station Probabilistic Safety Assessment', prepared for Public Service Company of New Hampshire and the Yankee Atomic Electric Company PLG-0300 December, 1983.

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2. DeVincentis, J., Public Service Company of New Hampshire, letter to i the NRC, SBN-617. January 30, 1984.  !

3. NUREG/CR-4452, ' Review of Relap 5 Calculations for H. B. Robinson, 5 Unit II Pressurized Thermal Shock Study', December 1985.

4. NUREG/CR-4540, 'A Review of the Seabrook Station Probabilistic Safety '

As s e s smer.t Containment Failure Modes and Radiological Source Terms'. Brookhaven National Laboratory, February 1986. '

5. Kiper, K. L., T. J. Casey, and W. Dookocil, 'Seabrook Station i Probabilistic Safety Study-Shutdown Modes 4, 5 and 6, prepared for i New Hampshire Yankee Division Public Service Company of New  ;

Hampshire, May 1988. '

6. New Hampshire Yankee Engineering Procedure No. 35010, ' Safety /  ;

Reliability Review of Plant Changes', effective December 13, 1988.

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7. Pickard, Lowe and Garrick, Inc., ' Risk-Based evaluation of Technical -

Specifications for Seabrook Station', prepared for New Hampshire ,

Yankee Division. Public Service Company of New Hampshire, PLG-0451, l August 1985. ,

t L 8. Fleming K. N., et al, 'Seabrook Station Risk Management and

, Emergency Planning Study', Pickard, Lowe and Garrick Inc., PLG-0432 L

o prepared for New Hampshire Yankee Division, Public Service Company of I New Hampshire December 1985. '

9. Fleming, K. N., et al, 'Seabrook Station Emergency Planning .

Sensitivity Study', Pickard, Lowe and Garrick, Inc., PLG-0465, l prepared for Public Service Company of New Hampshire, April 1986. ,

10. Fleming, K. N. and A. Torri, ' Risk Management Actions to Assure Containment Effectiveness at Seabrook Station', Pickard, Lowe and Garrick, Inc., prepared for New Hampshire Yankee Division, Public '

Service Company of New Hampshire PLG-0550, July 1987. t l

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