ML19268C172
| ML19268C172 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/16/1979 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| References | |
| NUDOCS 8001030602 | |
| Download: ML19268C172 (1) | |
Text
'l USNRC REE-e v;u, v Virginia Electric and Power Company North Anna Power Station, Unit fl. MPF-413 L'0V 16 P l,30 8
Docket No.
50-338 24 Hour Reportable Event Written Follow-Up (supplement)
Event:
ESF Systens Returning to Non-Safety Mode Upon Reset of CDA Signal LER/R0 79-141/01T-C While reviewing system operation. it was discovered that the recircu-lation cooling fans and the control red drive fans operate in a manner less conservative than that assumed in the accident analyses in the safety analysis report.
Actuation (CDA) y. the fans trip upon receipt of a Containment Depressurization Specificall signa]. When the CCA signal is reset, the fan will autena-tically restart.
The return of Emergency Safety Features (ESF) equipment to a non-safety mode without deliberate operator action is not consistent with FSAR Ccerunt 7.4 which states that two acticas are required to return a device to the non-safety featurs mode.
As stated in the FSAR. the return of ESF equipment to a non-safety mode is acecap11shed by resetting the appropriate actuation signal and subsequently operating the control switch for the device.
The cause of this discrepancy is unknown at this time.
This problen is presently being reviewed by engineering services.
There has been no effect on the. plant because of this discrepancy.
The 4mit is presently in refueling shutdown mode. This event is similar to LER/KD 79-141 and w1)) be jncluded in that 13 day report.
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