ML19312E540
| ML19312E540 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/30/1980 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8006050247 | |
| Download: ML19312E540 (2) | |
Text
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get NSIB NORTHERN STATES POWER COMPANY M I N N E A PO LI S. M IN N E SOTA S5401 May 30, 1980 Director of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Ef fect of DC Power Supply Failure on ECCS Performance
Reference:
(1) Letter, T A Ippolito (NRC) to L 0 Mayer (NSP), dated April 25, 1980 The referenced letter requested that NSP provide a schedule for completing evaluation of minimum ECCS equipment availability with a DC power supply failure for the Monticello Nuclear Generating Plant.
An evaluation of the effects of DC power supply loss irrespective of the break location or type has been conducted.
(Refer to Attachment 1.)
That evaluation is being expanded to consider loss of equipment due to water spillage.
We are continuing our investigation and expect to submit an updated list of available ECCS equipment by August 30, 1980.
l Should you have any questions, please contact this office.
. D.
l L 0 Mayer, PE Manager of Nuclear Support Services LOM/ JAG /ak cc: J G Keppler G Charnoff 80060501h h
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d e
ATTACHMENT 1 to NSP Letter dated May 30, 1980 DC Power Supply Failure Effects on ECCS Postulated Failure Resulting Configuration 250 VDC 2 LPCS + 4 LPCI + ADS A-125 VDC 1 LPCS + 2 LPCI + HPCI + ADS B-125 VDC 1 LPCS + 2 LPCI + ADS 11 Emerg D.G.
1 LPCS + 2 LPCI + HPCI + ADS 12 Emerg D.G.
1 LPCS + 2 LPCI + HPCI + ADS Auto Power Transfer Bus MCC 133B 2 LPCS + HPCI + ADS 143B 2 LPCS + HPCI + ADS 133A 1 LPCS + 2 LPCI + HPCI + ADS 143A 1 LPCS + 2 LPCI + ADS or 1 LPCS + 2 LPCI + HPCI + ADS Loss of Emergency Same as above Power Bus Loss of Primary Same as above Circuit Breaker Loss of Single ADS Valve All Systems Remain Loss of Inst. Air Supply All Systems Remain Loss of a Cooling Water Source:
Emerg Serv. Water 1 LPCS + 2 LPCI + HPCI + ADS RHR Serv. Water 2 LPCS + 4 LPCI Loss of One HVAC Train 1 LPCS + 2 LPCI + HPCI + ADS Short in Single Cable Tray One of the following depending on circumstances 1 LPCS + 2 LPCI + ADS 2 LPCS + HPCI + ADS 2 LPCS + 4 LPCI + ADS 1 LPCS + 2 LPCI + HPCI + ADS Failure of a panel not Same as above; however, no such failure that designed to prevent af fects ECCS has been identified propagation of fire or mechanical damage from one division to another
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