ML20004C261
| ML20004C261 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 05/28/1981 |
| From: | Withrow G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| GL-81-04, GL-81-4, NUDOCS 8106020445 | |
| Download: ML20004C261 (3) | |
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Consumes Power company 93 0
General Offices: 212 West Michigan Avenue. Jackson. Michigan 49201 Area Code 517788-05S0 U
May 28, 1981
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Director, Nuclear Reactor Regulation Att Mr Dennis M Crutchfield, Chief
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Operating Reactors Branch No 5 7-
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3 US Nuclear Regulatory Commission M'I g I
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BIG ROCK POINT PLANT - EMERGENCY 4
PROCEDURES AND TRAINING FOR STATION 3LACKOUT EVENTS (GENERIC LEnER 81-oh)
RESPONSE
NRC letter dated February 25, 1981 concerning station blackout ever.ts requested Consumers Power Company to review current plant operations to determine the capability to mitigate a station blackout event and promptly implement, as necessary, emergency procedures and a trainin6 program for station blackout events.
Consumers Power Company letter dated January 9,1981 provided historical infor-mation relative to loss of offsite power sources since Big Rock Point (BRP) startup in 1962. This information indicates that only three total losses of offsite power have occurred in ERP's existence. Since the addition of a second offsite power source in 1968, only one total loss of offsite power has occurred.
It should be noted that the duration of these loss of offsite power events was always less than one hour and that the emergency diesel generator started in less than 30 seconds and furnished emergency AC power. These conditions together with the capability of the emergency condenser to provide decay heat removal for up to four hours without cooling water makeup has resulted in no adverse safety consequences from the experienced total losses of offsite power.
Censumers Power Company letter dated March 31, 1981 provided the results of the BRP Probabilistic Risk Assessment (FRA). The PRA provides in Appendix I (pg I-89) the accident sequences leading to reactor ccre damage resulting from loss of offsite power initiated events. This infont. tion establishes the probability of total losq of offsite power accompanied by failure of emergency AC power at 2.3 x 10-3 per year. The highest probability accident sequence which is initiated 8196020445 l
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Mr Dennis M Crutchfield, Chief 2
Big Rock Point Plant Pay 28,1981 by total loss of off' site power accompanied' by fgilure of emergency AC.pover and results in reactor core d.amage is 2.5 x 10~ per year..This' sequence involves the following _ events:
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Loss of Offsite Power Failure.of Emergency Power Failure-of Makeup to. Emergency Condenser e
Failure to Restore Power in Short' Term.
Failure of Reactor Depressurization' System (RDS)/ Core Spray It is Consumers Power Company's conclusion that-based on past'historys and the PRA. established probability of reactor. core damage resulting fromLthe postulated station blackout event that consideration of this issue as a design basis event for Big Rock Point'is unwarranted. However, Consumers Power.has determined-that.
adequate capability exists to mitigate a station-blackout event. Operating pro-cedures exist and operator training has been conducted which address mitigation of station blackout events (specifically, Loss of Offsite Power, Loss of Trans-mission System and Loss of Emergency. Condenser). A -loss of offsite power due to efft. cts external to the plant also requires the Company Area Power Controller r
and Area Operators involvement fbr restoration of power. Annual requalification-including simulator training is currently provided for the actions required to mitigate station blackout events. Therefore, Consumers. Power plans no further actions to address station blackout events for Big Rock Point other than those.
that' may be required in modifying existing procedures to implement the BWR Owner's Group Dnergency Procedure Guidelines in accordance with NUREG-0737,.
Item I.C.l.
Gregory C Withrow (Signed)
Gregory C Withrov Senier Licensing Engineer CC Director, Region III, USNRC NRC Resident Inspector - Big rock Point page
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CONSUMERS POWER COMPANY Big Rock Point Plant Generic Letter 81-Oh Docket No 50-15ca-License No DPR-6 At the request of'the Commission and pursuant to the Atomic. Energy Act of '195h and the Energy Reorganization Act of 197h, as : amended, and the Commission's Rules and Regulations thereunder, Consumers Power Company submits our response to Generic Letter No 81-04,' dated February 25, 1981 entitled, " Emergency Pro--
cedures and Training for Station Blackout. Events." Consumers Power Company's.
response is dated May 28, 1981.
CONSUMERS POWER COMPANY By R B DeWitt (Siened)
R B DeWitt, Vice President Nuclear Operations Sworn and subscI-ibed to before me this 28th day of May 1981.
t Dorothy H Bartkus (Signed)-
(S"AL)
Dorothy H Bartkus, Notary Public Jackson County, Michigan My co= mission expires March 26, 1983 1
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