ML17290A883

Provides Updated Info Re Resolution of SBO for WNP-2

ML17290A883
Person / Time
Site:	Columbia
Issue date:	01/06/1994
From:	Parrish J WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-94-002, GO2-94-2, TAC-M68626, NUDOCS 9401140194
Download: ML17290A883 (6)

Text

ACCELERATED DI TRIBUTION DEMONS TION SYSTEM e

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9401140194 DOC.DATE: 94/01/06 NOTARIZED: NO DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION PARRISH,J.V. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Provides updated info re resolution of SBO for WNP-2.

DISTRIBUTION CODE: AO50D COPIES RECEIVED:LTR ( ENCL 0 SIZE: 3 TITLE: OR Submittal: Station Blackout (USI A-44) 10CFR50.63, MPA A-22 D NOTES' RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PDV PD CLIFFORD,J A INTERNAL: ACRS AEOD/DSP/TPAB D NRR/DE/EELB NRR/DRPE/PDII-4 REG

+~A/

FILE PLB 01 NRR/DSSA/SRXB D EXTERNAL: NRC PDR NSIC D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE( CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISIS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 13 ENCL ~ 4

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Bax968 ~ 3000George Wasbtngton Way ~ Rtchland, Wasbtngton 99352-096'8 ~ (509)372-5000 January 6, 1994 G02-94-002 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 UPDATED INFORMATIONREGARDING STATION BLACKOUT RESOLUTION (TAC No. M68626)

References:

1. Letter GO2-92-057, dated March 6, 1992, GC Sorensen (SS) to NRC, "Safety Evaluation of the Washington Public Power Supply System Nuclear Project Number 2 Station Blackout Analysis"

2. NUMARC 87-00, "Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors," revised August 1991

3. Letter, dated December 30, 1991, PL Eng (NRC) to GC Sorensen (SS),

"Safety Evaluation of the Washington Public Power Supply System (WPPSS) Nuclear Project Number 2 Station Blackout Analysis (TAC No.

M68626)"

4. Letter GO2-91-091, dated May 7, 1991, GC Sorensen (SS) to NRC, "Additional Information Regarding SBO (TAC No. 68626)" and Letter GO2-91-091, dated May 7, 1991, GC Sorensen (SS) to NRC, "Additional Information Regarding SBO (TAC No. 68626)"

5. Letter GO2-92-099, dated April 15, 1992, GC Sorensen (SS) to NRC, "Safety Evaluation of the Washington Public Power Supply System Nuclear Project Number 2 Station Blackout Analysis (TAC No. M68626)"

6. Letter GO2-92-183, dated July 31, 1992, GC Sorensen (SS) to NRC, "Station Blackout Supplemental SER and Implementation Schedule, 10CFR50.63(c)(4), TAC No. M68626"

7. Letter, dated June 26, 1992, RR Assa (NRC) to GC Sorensen (SS),

"Supplemental Safety Evaluation (SSE) of the Washington Public Power Supply System Nuclear Project No. 2 (WNP-2) Station Blackout Analysis (TAC M68626)"

':. "-',.P 940fx40X9O 94OXa~

PDR ADOCK 05000397,

'";.PBR.=,'.

2'age Two UPDATED INFORMATIONREGARDING STATION BLACKOUT (TAC No. M68626)

The purpose of this letter is to provide updated information regarding resolution of Station Blackout (SBO) for WNP-2.

Prima on inmen Tem eratures and Pr ur In Reference 1 the Supply System provided the initial temperature assumptions and the final temperatures and pressures calculated for a four hour Station Blackout at WNP-2 as:

Initial Final Pressure ace T~em 'F T~em 'F sl Drywell 135 280 40 Wetwell air 135 240 42 Wetwell water 90 240 These temperatures and pressures were calculated based upon an assumed primary system leakage rate of 200 gpm. This leakage value was chosen as the resolution of Generic Issue 23 (Reactor Coolant Pump Seal Integrity) was uncertain at the time the original analysis was performed. The Supply System recognized that a leakage value greater than the 18 gpm/pump value for BWR SBO resolution might be required upon resolution of Generic Issue 23. It now appears that such a value willnot be required of BWRs and the rulemaking to achieve resolution of Generic Issue 23 will only apply to PWRs. Consequently, we have completed the primary containment heatup analysis for WNP-2 for an assumed primary system leakage rate of 61 gpm I

which includes the 18 gpm/pump required by Appendix of Reference 2 for BWRs plus the maximum Technical Specification value of 25 gpm.

With a leakage rate of 61 gpm, the four hour primary containment temperatures and pressures are:

Initial Final Pressure T~em 'F T~em 'F ~sia/ )~si ~

Drywell 135 229 35.3/20.6 Wetwell air 150 179 29.7/15.0 Wetwell water 90 209 The initial temperature assumption for the wetwell airspace was changed from 135 to 150'F to reflect the fact that there is no Technical Specification limit on this parameter but that a annunciator response procedure does require action at 147'F.

The above temperatures and pressures were determined for an initial power of 3629 MWt which is greater than the currently planned power uprate level of 3486 MWt.

ta i4 Jagt'. Three UPDATED INFORMATIONREGARDING STATION BLACKOUT (TAC No. M68626)

Condensate Invento The Reference 3 SBO Safety Evaluation for WNP-2 states in Section 2.3.1 that "The licensee indicated that the Technical Specifications (TS) require a minimum condensate storage tank reserve of 135,000 gallons of water".

In Reference 4 the Supply System corrected a previous statement in this regard and informed the NRC that the Technical Specification value of 135,000 gallons only applies in Modes 4 and

5. In Reference 4 other means of ensuring the inventory of water during Mode 1 were discussed. These other means of ensuring the inventory are acknowledged in Section 2.3.2 of the Safety Evaluation.

Batte R om Heatin In Reference 5 it was stated that the battery room temperatures would be maintained to 74 +1'F in the heating and cooling modes.

As part of the implementation of improved setpoint methodology for WNP-2, the setpoints for the battery room heaters have been recalculated. The Lower Analytical Limit used in these calculations is the Technical Specification value of 60'F. This limit was not established at 74'F as the consideration for the 6'F deadband and environmental, accident and other effects would have resulted in excessively high battery room temperatures. To ensure that the rooms containing batteries B1-1 and Bl-2 are maintained at or above 74 F during normal operation, administrative controls are in place to require corrective action should the temperature be less than 74'F.

. Parrish (Mail Drop 1023) ssistant Managing Director, Operations AGH/bk CC: KE Perkins - NRC RV NS Reynolds - Winston 8c Strawn JW Clifford - NRC DL Williams - BPA/399 NRC Site Inspector - 927N