ML20127N502
| ML20127N502 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 04/27/1978 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9212010288 | |
| Download: ML20127N502 (1) | |
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HSp PM NOMTHERN 5 TATE 8 P O W E M.
COMPANY M I N N E A PO L.l S. M I N N E G OTA 9 5401 i
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Mr R Bevan.ons v Director of Nuclear Reactor Regulation 4/27/78 Q S Z
fy U S Nuclear Regulatory Cocuission a
Za3 Washington, DC 20555 E
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MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Elimination of Valve Closure Signal for ECCS Considerations On April 20, 1978 General Electric informed us of a potential component failure in the LPCI loop selection logic which could cause closure of the recirculation pump suction valve in the loop postulated to have been ruptured. The current ECCS analysis takes credit for a blowdown and more rapid reflood assuming the suction valve to be open.
A generic ECCS analysis was perfomed to detemine the effect of a closed-suction valve. The results showed that peak clad temperature did not exceed the 2200 F limit. This gave justification for continued operation 0
without fomal reporting.
The situation was discussed by telephone with the Monticello Project Manager, Mr R Bevan on April 20; this letter is being provided at his request.
A circuitry change has been made which removes the closure signal from the recirculation pump suction valve. This will be reported as a design change in accordance with 10 CFR 50.59.
Having made the change, the ECCS will perform as analyzed in our filings dated August 4,1975 and i
September 15, 1977.
h' L 0 Mayer, PE Manager of Nuclear Support Services LOM/MHV/deh cc: J G Keppler G Charnoff
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PDR ADOCK 05000263 1
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