ML20090F448
| ML20090F448 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Crane  |
| Issue date: | 05/20/1977 |
| From: | Janis J BABCOCK & WILCOX CO. |
| To: | Klingman R GENERAL PUBLIC UTILITIES CORP. |
| References | |
| TASK-03, TASK-06, TASK-11, TASK-3, TASK-6, TASK-GB B&W-0204, B&W-204, NUDOCS 8307050486 | |
| Download: ML20090F448 (2) | |
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Q,.Q006 0003 Phu3 Babcock &Wilcox po
,c.n.,.uon aroup P.O. Box 1260, Lynchburg, Va. 24505 Telephone:(804) 384 5111 May 20, 1977 i
Mr. R. M. Klingaman Manager, Generation Engineering Metropolitan Edison Company P.O. Box 542 Reading, Pennsylvania 19603
Subject:
Three Mile Island Nuclear Station - Unit No. 1 Containment Flooding Incident
Dear Mr. Klingaman:
B&W wishes to inform you of an incident that occurred during the preoperational testing of a nuclear power plant with a B&W NSSS which you should review for applicability to your design.
On October 15, 1976, during preoperational testing at the Davis-Besse Nuclear Plant, the containment emergency sump isolation valves were inadvertently opened allowing water from the BWST to drain into the contaiment building. By the ti=a the valves were closed (approximately two minutes elapsed time), 40,000 gallons.
of water had drained into the containment building, wetting the bottom of the then cold reactor vessel.
B&W is concerned that adequate measures be undertaken to preclude such an event particularly when the reactor coolant system is at operating temperature and pressure. B&W's analysis on RC components assumes that the reactor building is dry when the system is at temperature and pressure, is., that no flooding of any portion of the components and supports is allowed to occur under non-faulted conditions. For this reason, B&W recoemends that you review your plant layout to determine the following:
1.
Whether an inadvertent opening of the sump isolation valves would allow BWST water to drain into the containment building or whether other valves in the decay heat or BWST piping would present such flow to the containment.
2.
Whether your specific containment design would preclude wetting portions of the NSSS or its supports in the event of such containment flooding.
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Charles Sapiro CSR Doyle Reporting Inc.
Tne s ecoew a w; icon company i Est ei.sneo iss7 Q
8307050486 770520 PDR ADOCK 05000289 S
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O Babcock &Wilcox JANIS TO KLINGAM.W MAY 20, 1977
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If component wetting wo.ild occur in your plant, B&W recoc= ends that design modifications be made to preclude contain=ent flooding. The following design modifications are suggested:
1.
Addition of check valves in commen header to prevent flow from BWST to sump.
2.
Addition of valve interlock to prevent opening of su=p isolation valves when the BWST isolation valves are open.
If you have any questions or require additional information, pelase advise.
Very truly yours, ky,d ~ 0 Joel T. J s
Service Manager JTJ/hh cc: GP Miller JP O'Hanlon CR Montgomery LC Rogers SL Smith O
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