ML20003E076
| ML20003E076 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 03/16/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20003E075 | List: |
| References | |
| NUDOCS 8104020204 | |
| Download: ML20003E076 (1) | |
Text
.
l SAFETY EVALUATIM BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR TRE BOSTON EDISON COMPANY ON PILGRIM NUCLEAR PONER STATION UNIT I DIESEL GENERATOR LOCKOUT On 11 arch 29,1977, a generic letter was sent to all licensees request ng that they provide information regarding the status annunciator system for the diesel generators at their facilities. This request for infor-mation was prompted by reports from licensees, i.e., LERs, on incidents where diesel generators failed to respond to automatic start signals because control switches or lockout and shutdom relays were left in the shutdown condition by operators unaware of their status. The principic wasons for this lack of awareness were: (1) the sharing of annuna..ar stations for both disabling and non-disabling alarm conditions; (2) wording on annunciator w'ndows for disabling conditions which did not specifically say a diesel generator emergency start was blocked; and (3) disabling conditions which were not annunciated in the control room.
The licensee responded by letter dated June 1,1977, describing the diesel generator annunciator system at the Pilgrim Nuclear Power Station.
A review of the licensee's response by our consultant, LLNL, has identified two areas of concern:
1.
The position of the air supply SHUT-OFF valve is not annunciated to the Control Room.
2.
If the diesel generator is in the TEST mode and the shutdown relay is energized, it appears that the ~ alarm can be cleared in the Control Room after the local alarm is cleared. This raises the following question -
can the local alam be cleared without clearing the shutdown relay?
If so, an automatic start could be blocked if the local alam were cleared without first reverting the shutdown relay and the operators were not aware of it.
i By letter dated October 20, 1978 and telecon with the licensee on l
February 4,1981, the areas of concern have been resolved as follows:
1.
Functionally. testing the D/G after maintenance and daily checkf1g the position of the shut-off valves provide adeg; ate assurance that the D/G will notz be left in en inoperable mode due to the incorrect positioning of the air start shutoff valve. No rnodif,1 cation is necessary.
2.
The local alam cannot be cleared without clearing the condition which caused the alam. The alarm can be silenced, but not cleared (i.e., the local alam cannot be cleared ~wi.thout clearing the shutdown relay).
No modification is neceesary, i
8104020 M
.