ML17286B204

Responds to Generic Ltr 88-20,Suppl 4 Re Individual Plant Exam for External Events.Util Will Also Address Hazards Associated W/Volcanic Eruption.Events Initiated by Internal Fires Will Be Evaluated by Level 1 PRA

ML17286B204
Person / Time
Site:	Columbia
Issue date:	12/18/1991
From:	Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-20, GO2-91-227, TAC-M74489, NUDOCS 9112270206
Download: ML17286B204 (12)

Text

ACCELERATED DI UTION DEMONS ATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9112270206 DOC.DATE: 91/12/18 NOTARIZED: YES DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION SORENSEN,G.C. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk) R

SUBJECT:

Responds to Generic Ltr 88-20,Suppl 4 re individual pla'nt exam for external events. Util will also address hazards associated w/volcanic eruption.Ev'ents initiated by internal fires will be evaluated by Level 1 PRA. D DISTRIBUTION CODE: AOIID COPIES RECEIVED:LTR i ENCL i SIZE: 5 TITLE: Generic Ltr 88-20 re Individual Plant Evaluations NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D PD5 PD 1 1 ENG,P.L. 1 1 D

INTERNAL: ACRS HOUSTON,M. 1 1 AEOD/DSP/TPAB 1 1 NRR HERNAN,R. 1 1 NRR/DREP/PRAB 2 2 REG 1 1 1 REG 2 1 1 REG 3 1 1 REG 4 1 1 o( 1 1 RES FLACK,J. 6 6 RES MITCHELL,J. 1 1 RES/DSIR/SAIB/B 7 7 EXTERNAL: NRC PDR 1 1 NSIC 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISI'RIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 28

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WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 9935Z December 18, 1991 G02-91-227 Docket No 50-397 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

NUCLEAR PLANT NO. 2, OPERATING LICENSE NPF-21 INITIAL SUBMITTAL OF INDIVIDUAL PLANT EXAMINATION FOR EXTERNAL EVENTS (IPEEE) (TAC N0.9174489)

Reference:

Letter, G02-89-203, GC Sorensen (SS) to NRC, "Initial Submittal of Individual Plant Examination (IPE),"

dated November 1, 1989 Pursuant to the request in Generic Letter 88-20,'upplement 4, this letter is to inform the NRC of the Supply System's intention in responding to the Generic Letter and associated NUREG-1407. This letter satisfies the 180-day response requirement of Supplement 4 to Generic Letter 88-20 by providing:

I. The method and approach selected for performing .the WNP-2 IPEEE.

II. A description (by reference) of the methods to be used, and III. Schedule milestones for performing the IPEEE and submittal of the WNP-2 plant-specific results to the NRC.

Each of these items are discussed in more detail in the following sections.

I. Method and A roach of WNP-2 IPEEE The Supply System will address each of the five external events delineated in Generic Letter 88-20, Supplement 4:

1. Seismic Events

2. Internal Fires

3. High Winds and Tornadoes External Floods

5. Transportation and Nearby Facility Accidents In addition, due to the proximity to the Cascade Mountain Range, the Supply System. will address the hazards associated with volcanic eruption.

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Document Control Desk Page Two INITIAL SUBMITTAL OF INDIVIDUAL PLANT EXAMINATION FOR EXTERNAL EVENTS (IPEEE) (TAC NO. 74489)

The examination process for risks associated with the external events will follow closely the process used for the WNP-2 IPE (Reference). The Supply System team and approach utilized for the IPE Program will be utilized for the IPEEE. This approach maximizes the utilization of internal resources to complete the evaluations, using consultants for training and peer review of the products. Therefore, as with the IPE, the Supply System will involve its staff with all aspects of the IPEEE (either in performing the analysis or by technical review of the analysis) and by having a peer review of the results. Independent in-house review of the documentation will be used, as in the IPE, to validate the accuracy of the process and results. The IPEEE methods will then be applied to issues other than the IPEEE itself.

II. WNP-2 IPEEE Methods Descri tion The NRC has identified several methods in the Generic Letter and NUREG-1407 which are deemed acceptable to address each of the external events. The Supply System has evaluated these methods in terms of capa-bility to identify vulnerabilities, interface with the WNP-2 IPE quanti-fied risk results, address generic issues, and benefit the Supply System staff in knowledge gained in understanding the total risk associated with WNP-2. The methods chosen for each category of external events are dis-cussed below.

A. Seismic Events The seismic IPEEE will be performed by seismic PRA methods in accor-dance with NUREG/CR-2300 or equivalent procedures. The enhancements requested by the NRC in Appendix I of Generic Letter 88-20, Supple-ment 4 will be included. This analysis will be a Level I PRA with an adequate containment evaluation to identify vulnerabilities due to seismic events that are different than those identified in the IPE. The seismic PRA will utilize a site-specific seismic hazards analysis.

B. Internal Fires Events initiated by internal fires will be evaluated by a Level I PRA. However, the procedures normally associated with the standard approach (e.g., NUREG/CR-2300) will be modified to take advantage of the EPRI FIVE methodology's screening procedures. This will allow the areas that don't need to be critically examined to be identified and screened out at the beginning of the evaluation rather than quantifying all areas and eliminating the risk insignificant areas later in the analysis. The issues identified in the Fire Risk Scoping Study will be addressed during the analysis and walkdown.

The issues will be addressed to the extent of general resolution at that time between the NRC and the utility industry. The containment performance will be examined to the extent of identifying any vul-nerabilities different than found for the IPE.

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Document Control Desk Page Three INITIAL SUBMITTAL OF INDIVIDUAL PLANT EXAMINATION FOR EXTERNAL EVENTS (IPEEE) (TAC NO. 74489)

C. High Winds, Floods, Transportation and Nearby Facility Accidents, and Volcanoes The screening approach depicted in Figure 1 of Generic Letter 88-20, Supplement 4 will be used to evaluate these external events. A preliminary screening, based on the WNP-2 FSAR, has already been performed and indicates the 1975 SRP criteria are met for each event. This result will be validated and documented for the IPEEE submittal.

D. Coordination with Other External Event Programs The issues of GI-131, "Potential Seismic Interaction Involving the Movable In-Core Flux Mapping System Used in Westinghouse Plants" and the "Eastern U.S. Seismicity (The Charleston Earthquake) Issue" are not applicable to WNP-2 and will not be addressed in the IPEEE.

NUREG/CR-5088, "Fire Risk Scoping Study" and GI-57, "Effects of Fire Protection System Actuation on Safety-Related Equipment" will be addressed in the Internal Fire Events IPEEE. USI A-45, "Shutdown Decay Heat Removal Requirements", USI A-17, "System Interactions in Nuclear Power Plants", USI A-40, "Seismic Design Criteria, A Short-Term Program", and USI A-46, "Verification of Seismic Adequacy of Equipment in Operating Plants" will be addressed. WNP-2 is a non-A-46 plant, but will review spatial interactions through its seismic walkdowns. If other generic issues are resolved through the IPEEE, the Supply System will so identify them in its final report.

III. WNP-2 IPEEE SCHEDULE MILESTONES Generic Letter 88-20, Supplement 4 requests submittal of the IPEEE results by June 28, 1994. The Supply System, as noted above, intends to use internal resources for the IPEEE as it has with the IPE. Since our ap-proved submittal date for the IPE is September 1, 1992, start of the IPEEE will be delayed until that time. Therefore, the Supply System will submit the final IPEEE results report June 28, 1995, making it a 34 month effort.

The major milestones for the WNP-2 IPEEE are as follows:

~ Complete the Seismic Event Analysis June 28, 1994

~ Complete the Internal Fire Analysis Dec. 31, 1993 Complete the Other Ext Events Analysis April 30, 1994

~ . Screen and Rank Dominant Risk Contributors June 28, 1994 Address Generic Issues Dec. 31, 1994 Complete Peer Reviews of IPEEE Results March 31, 1995 Submit IPEEE Report to NRC June 28, 1995

V Document Control. Desk Page Four INITIAL SUBMITTAL OF INDIVIDUAL PLANT EXAMINATION FOR EXTERNAL EVENTS (IPEEE) (TAC NO. 74489)

The Supply System agrees with the NRC staff that procedures developed for reso-lution of A-46, in particular, the walkdown procedures, be used as much as possible for the seismic IPEEE, including the necessary training on these proce-dures. However, because of the delay in issuance of the Supplemental Safety Evaluation Report (SSER) on the SHRUG's Generic Implementation Procedure, the June 28, 1994 milestone for the Seismic Event Analysis may not be able to be met. If the SSER is further delayed to where the WNP-2 IPEEE Report to the NRC cannot be submitted by June 28, 1995, an extension to the submittal date will be requested.

Very truly yours, G. C. Sorensen, Manager Regulatory Programs ROV/bk cc: JB Hartin - NRC RV NS Reynolds - Winston 5 Strawn PL Eng - NRC DL Williams - BPA/399 NRC Site Inspector - 901A

STATE OF WASHINGTON)

Subject:

Initial Submittal of Individual

) Plant Examination For External Events COUNTY OF BENTON )

I. A. G. HOSLER, being duly sworn, subscribe to and say that I am the Manager, WNP-2 Licensing, for the WASHINGTON PUBLIC POWER SUPPLY SYSTEM, the applicant herein; that I have the full authority to execute this oath; that I have reviewed the foregoing; and that to the best of my knowledge, information, and belief the statements made in it are true.

DATE 0 ece~ 6' 8, 1991 A. G. Hosier, Manager WNP-2 Licensing On this date personally appeared before me A. G. HOSLER, to me known to be the individual who executed the foregoing instrument, and acknowledged that he signed the same as his free act and deed for the uses and purposes herein mentioned.

GIVEN under my hand and seal this ~/ day of 1991.

No ry Public n and o the STATE OF WASHINGTON Residing at Kennewick Washin ton My Commission Expires A ril 28 1994

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