ML19316A588
| ML19316A588 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/19/1975 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19316A586 | List: |
| References | |
| NUDOCS 8001130094 | |
| Download: ML19316A588 (1) | |
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DUKE POWER COMPANY OCONEE UNIT 2 i
Report No.: A0-270/75-15 Report Date: August 19, 1975 Occurrence Date:
August 5, 1975 Facility: Oconee Unit 2, Seneca, South Carolina Identification of Occurrence:
Failure of amplifier in Reactor Protective l
System Channel D power imbalance circuit l
Conditions Prior to Occurrence:
Trip recovery in progress Description of Occurrence:
i On August 5,1975, during surveillance testing of Oconee Unit 2 Reactor
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Protective System (RPS) Channel D, it was noted that a faulty amplifier l
in the power imbalance circuit of the power-imbalance-flow trip function j
had resulted in a trip setpoint less conservative than allowed by Technical Specification 2.3.
For this test, RPS Channel D was placed in l
manual bypass, leaving the system'in a two-out-of-three logic.
Power and i
imbalance test signals were set and a flow test signal then decreased to establish a trip point. Because of the faulty amplifier in the imbalance circuit, the trip point decreased to 109.5 x 106 lbs/hr rather than the I
required trip point of 110 x 106 lbs/hr.
RPS Channel D was left in manual bypass since a replacement amplifier was not immediately available.
The i
last periodic test of RPS Channel D was completed on July 9, 1975.
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Designation of Apparent Cause of Occurrence:
A faulty amplifier was determined to be the apparent cause of this i
occurrence.
This was the first failure of this component and is regarded as a random failure.
Analysis of Occurrence:
This amplifier is part of the power imbalance circuit of the power-imbalance-flow trip function.
The failure of this amplifier resulted in a trip point less conservative than required; however, a trip of two of the three remaining RPS channels would have performed this function if necessary.
It is concluded that the health and safety of the public was not affected.
Corrective Action:
The faulty amplifier will be replaced as soon as a replacement is available.
l Until that time, RPS Channel D will remain in manual bypass. The Oconee periodic surveillance program is considerad adequate to identify random failures of this nature.
80011300*/ 9 1
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