ML19317F487
| ML19317F487 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/05/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19317F479 | List: |
| References | |
| RO-270-76-07, RO-270-76-7, NUDOCS 8001140717 | |
| Download: ML19317F487 (1) | |
Text
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r ym N-DUKE POWER COMPANY OCONEE UNIT 2 i
Report No.: R0-270/76-7 Report Date:_ August 5, 1976 Occurrence Date:_ July 6, 1976 Oconee Unit 2, Seneca, South Carolina Facility:
Failure of Reactor Protective System Channel Identification of Occurrence:
"B" to trip on high pressure setpoint during startup Conditions Prior to Occurrence:
Startup in progress Description of Occurrence:
On July 6, 1976, during the startup of Oconce Unit 2, Reactor Protective System (RPS) Channel "B" failed to trip as required when the reactor This is the high pressure setpoint coolant pressure reached 1720 psig.
when the RPS is in the shutdown bypass mode during startup or shutdown.
The other three channels of the RPS did function properly.
Apparent Cause of Occurrence:
Investigation revealed that the instrument root valve for the RPS Channel This resulted "B" pressure transmitter had been inadvertently left closed.
in isolation of the pressure transmitter which prevented the channel from The valve had been left tripping when the 1720 psig setpoint was reached.
3 open as required following calibration of the pressure transmitter on May 2, 1976, but had been closed at some subsequent time before the unit startup was initiated.
Analysis of Occurrence:
Although RPS Channel "B" failed to trip as required in the shutdown bypass mode, the other three RPS channels tripped when the 1720 psig setpoint was reached.. The Reactor Protective System utilizes a two-out-of-four redundant logic, and would have been disabled only if two other channels were
. It is concluded that this occurrence did not impair the inoperable.
operability of the Reactor Protective System,and therefore, the health and safety of the public was not affected.
Corrective Action:
followir.-
Station procedures are currently being revised to assure that, refueling outages, instrumentation is checked for proper operation prior to following the performance of maintenance, unit heatup; and to assure that, These instrument valves are returned to their pre-maintenance position.
. revisions will be completed by August 15, 1976.
It is felt that these measures will prevent further recurrences of this type.
8001140'7/7
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