ML19247A051
| ML19247A051 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Arkansas Nuclear, Crystal River, Rancho Seco, Crane  |
| Issue date: | 07/20/1979 |
| From: | Geissler G BABCOCK & WILCOX CO. |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7907270182 | |
| Download: ML19247A051 (2) | |
Text
Babcock &Wilcox e - r cenere e,,c,cuo P.O. Box 1260. Lynchburg, Va. 24505 Teiepnone: (804) 384-5111 July 20, 1979 SD - 313 5 0
.'f O A 50-346 Mr. Edson G. Case d -Mk Deputy Director
,270 Office of Nuclear Reactor Regulation
$87 U.S. Nuclear Regulatory Com:iission y -3[@
Washington, D.C.
20555
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@O -3l>
Dear Mr. Case:
Attached please find a representative letter which is being forwarded @
S~
to all B&W operating plants this morning, July 20, 1979.
This action informs the utility to trip all RC pumps in the event of an ESFAS actua-tion caused by low RC pressure.
If you have any questions, please contact me at Ext. 2536.
Very truly yours, George 0. Geissler Licensing GOG:dsf Attachment 424 270 h oP 5
1 1'
E s e e 3cc:cx & w ce< c;mcacy, Es, ion rec :ser 7gg s
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Babcock &Wilcox ec.e, cene,etien c,cu, P.O. Bcx 1260, Lynchburg, Va. 24505 Tefephene: (804) 384-5111 July 20, 1979 All B&W Operating Plants
Subject:
Revised Operating Guidelines for RC Pumps Upon Receipt of ESFAS Actuation Gentlemen:
The Babcock & Wilcox Company has recently completed additional small break LOCI. analyses which have identified a potentially unsafe condi tion.
The details of the analyses were discussed with the owners' representatives on July 18,1"79.
In summary, Appendix K criteria may be exceeded for a low probability event involving a 2
2 certain range of small breaks (approximately 0.025 ft to 0.2 ft )
and the subsequent loss of RC pumps after the system void fraction has achieved a high value. Analyses have been performed which confirm a safe situation if the RC pumps are tripped promptly in the transient prior to establishing a high void fraction.
Based upon the above information, you are requested to promptly initiate the following B&W recommendation:
Upon receipt of an ESFAS actuatien caused by low RC pressure, all operating RC pumps must be tripped immediately.
This revised criteria will of course alter the "immediate action" portion of the Small Break Operator Suidelines previously issued.
If there are further questions, please advise.
Very truly yours,
Service Manager 424 271 ine B 3tsccck L ?,"'ccx Cyp 3ry EMac:sred:"'