ML20091G981
| ML20091G981 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 12/11/1991 |
| From: | Burski R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| W3F191-0676, W3F191-676, NUDOCS 9112190257 | |
| Download: ML20091G981 (3) | |
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p.F.Ouroki K31> 191 -0G76 Al.05 UA Deccinher 11, 1991 U.S. Nuclear lleguk tory Conunission ATTN: Document Control Desk Washin gt on,1). C, 20355 Subject :
Waterford 3 Sl?S Docket No. 50-3h2 1.leense No. NPF-3h Comments on Preliminary " Accident Sequenen Preenesor Program Cohl Shuulown Analysis" for Waterforal 3 Gentlemen:
In response to the November 29, 1991 letter from David 1,. Wigginton to Ross P.
Ilarkhu rst, the At tachment provhles our conunents on the subject preliminary report, whleh addresses the.luly 14,1980 loss of shutdown cooling event that occurred at haterford 3.
We wish to express our appreciation for the opportunity given to provide our comments on this preliminary report.
Shoul:1 you have any questions on our comments or need additit.nal information, please contact Hoy Prados at (501) 739-GG32.
Very truly yours,
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. j'ht,t t th RFB/IlWl'/ssf Attachment ec:
R.D. Martin, NitC Region IV D.I.. Wigginton, NitC-NilR N.S. Reynelds 11.11. McGeheo NRC Resident inspectors Office d
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ATTACllMENT to W3F191-UG70 Pago 1 of 2 4
Commenta on Prellmhary Accitlent Sequeneo Precuraor Program Cold Shutdown Event Analysis" For Waterford 3 J
1.
Page A-232 Event Deserlylont Par.1 - The elevation of the centerline of tho 1
hm legs is 13' el 1/ 2", notTo?'.
2.
Page A-232, Event Demeription. Par.,1 suid einewhero nappplicablo - llofueling water storage tank (ItWST) should he refueling water stontgo pool (ItWS P).
3.
Pago A-235, Par. 3 - The charging pumps are characterized as providing unborated water injection. Although the charging pumps can luject unborated water, they are normally aligned to take suction from a borated source of water.
4.
Puno A-2l35, Item b - The assumption was made that only ono LPSI pump wan avall*lo since the other LPSI pump cavitated whilo taking suction from theit S hot leg. Ilowever, it is highly llkuly that this LPSI pump could aluo i ve been recovered by switching suction to the itWSP.
In addith *a the charging pumps eauld inject borated water which would as a mantmum delay the timo for core uncovery (if not prevent coro-uncovery).
5.
Pago A,235, Analysis Approach - The analysis does not credit continued umkoup for core cooling success because the IICS was closed, llowever, with no decay heat removal, itCS pressuro would increase due to boiling in the core until thu low temperature overpressure protection (LTOP) relief valves would open at approximately.130 pala. Operators wot.ld respond to this loss of inventory accordhig to their procedures by injecting with the llPSI pump. Thus, a once through cooling path would be established with feed by llPSI lujection and bleed by the LTOP relief valves. The LTOP reller valves dischargo to the containment sump which would allow reelreulation using the llPSI pump if the refueling water storago pool empties.
Although flow mir,ht be 1
intermittent as cool water injected to the core would stop the bolling and would reduce 11CS pressure causing the relief valve to resent, adequato core cooling would be provided. Thus, an additional system failuro would be necessary, given failure of Illlit recovery and steam generator heat removal, to reach core damage..This could reduce the conditional core damago probability by at least un order of magnitude or two.
6,.
Page A-230. ' Item c - The failure probability given to. !!Illt recovery t'oos not seem to reflect the considerable amount of time available to reet. er 111111 before core damage would occur. Filling the ItCS to a higher lovel timn mid-loop using the llPSI or LPSI pumps would considerably delay core uncovery by increasing liquf'l heat capacity and aid recovery efforts by campressing the vapor bubblo tu the I. PSI pump sucilon line. These potential actions do not appear to have been considered.
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ATTACilMENT to W3F101 -0070 '
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Pago 2 of 2
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7.
Pato A 236, item d - In addition to the Emergency Feedwater puinps,
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Waterford 3 has a motor driven Auxillary Feedwater pump that is also j
. capable of providing water to tLo ateam generators for makeup, it is not clear if this alternato and diverse makeup path is considered in the I
failure probability for steam generator cooling.
i 8.
Paste A-238 - The centerlino elevation of the loop seal in the shutdown couting suction piping is 23', not 22', The bottom of the llWSP is at elevation i
l'.
j D.
Tago A-93G, Analysis itenuits
'I he first sente neo should read "The estinated l
conditional co re damage probability assuelated with t he loss of IICS level and Illitt cooling for the July 14,198G,- Waterford 3 ovent la (now noinber un a result 'of commental,"
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