ML17244A220
| ML17244A220 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/29/1978 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | White L ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 7812110038 | |
| Download: ML17244A220 (2) | |
Text
Docket Ho. 50-.244 Rochester Gas 8 El.ectric Corporation ATTN:
Mr. Leon D. Mhite, Jr.
Vice President Electric and Steam Production 89 East Avenue Rochester, Hew York 14649 Gentlemen:.
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T RE:
CONTAINMENT PURGING DURING NORMAL PLANT OPERATION A number of events have occurred over the. past several years which directly relate to the practice of containment purging during normal plant operation.
During recent months, two specific events have-occurred which have raised several'uestions relative to potential failures of automatic isolation of the large diameter purge pene-trations which are used during power operation.
On July 26,
- 1978, the Hortheast Nuclear Energy Company reported. to the HRC such an event at Millstone Unit Ho. 2, a pressurized water reactor located
.in Hew London County, Connecticut.
On September 8, 1978, the Public Service Electric and Gas Company reported a similar event at Salem Unit Ho. 1, a pressurized water reactor located in Salem County, Ne<v Jersey.
During a review of operating procedures on July 25, 1978, the licensee discovered that since May 1, 1978, intermittent containment purge operations had been conducted at Millstone Unit No.
2 with the safety actuation isolation signals to both inlet and outlet redundant containment isolation valves (48 inch butterfly valves) in the purge inlet and outlet penetrations manually overridden and inoperable.
The isolation signals which are required 'to automatically close the purge valves for containment integrity were manually overridden to allow purging of containment with a high radiation signal present.
The manual override circuitry designed by the plant's architect/engineer defeated the high radiation signal and all other isolation signals to these valves.
To manually override.
a safety actuation signal, the operator cycles. the valve control switch to the'.closed position and then to the open position.
This action energized'a'elay which blocked the -safety signal and allowed manual operation indep'endent of any safety actuation signal.
This circuitry <<as designed to permit reopening these valves after an accident,to allow manual operation of certain safety equipment.
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