ML19241B055
| ML19241B055 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/11/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 7907110607 | |
| Download: ML19241B055 (2) | |
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flay ll,1979 Docket fio. 50-245 Mr. Boyce H. Grier Director, Region I Office of Inspection and Enforcement U. S. fiuclear Regulatory Commission 631 Dark Avenue King of Prussia, Pennsylvania 19406
References:
(1)
Boyce Grier ftter to W. G. Counsil, dated April 17,19/9, forwarding I & E Bulletin 79-09 (2) General Electric Service Advice Letter fio.175 (CPDD) 9.3 Mil; stone fluclear Power Station, Unit fio.1 General Electric Type AK-2 Circuit Breakers In Safety Related Systems
Dear it.'. Grier:
Referens e (1), which addresses failures of General Electric type AK-2 circuit breakers in safety related systems, requests that power reactor facilities with an operating license detemine whether or not these type of breakers are used in safety related systems at their facility.
A survey of the 4SO volt circuit breakers at Millstone Unit 1 has disclosed that General Electric AK-2A-25-1, AK-2A-50-1 and AK-2A-75-1 circuit breakers are enployed in safety related systems.
- However, none of thEse circuit breakers have the undervoltage tripping device that has caused the failures described in Reference (1).
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4 lir. Boyce H. Grier May 11, 1979 All the liillstone Unit 1480 volt circuit breakers that are required to open during a loss of nomal power are tripped by supplying a signal from the " Loss of flomal Power" logic circuitry to the nomal breaker shunt trip coil which is energized any time it is desired to open the breaker. As e result, the trip mechanisms are not subject to failure as described in Reference (1).
He trust the above inforr.ation is responsive to your request.
Very truly yours, fiORTHEAST fiUCLEAR EtiERGY C0f tPAtlY f.
kl0I.A W. G. Counsil Vice Pt'sident 4
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