ML20062G526
| ML20062G526 | |
| Person / Time | |
|---|---|
| Issue date: | 12/22/1978 |
| From: | Felton J NRC OFFICE OF ADMINISTRATION (ADM) |
| To: | Kehoe K CENTER FOR DEVELOPMENT POLICY |
| Shared Package | |
| ML20062G528 | List: |
| References | |
| FOIA-78-342 NUDOCS 7812290156 | |
| Download: ML20062G526 (1) | |
Text
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f o i;i l_ RPS Channel A, RC Flow Indication began reading high on July 29, 1978 and to es! I was valved out-of-service on July 31.
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i o.. i ! readings were caused by a leak on the impulse line and it was decided to leave the channel bypassed until the next available outage. The remaining i o,. i ; channels were all operable and would have tripped on 2-out-of-3 logic. The Io i I I RPS was capabic of performine its function, thus the incident did not adversely I o is i 1 effect public health or safety.
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DUKE POWER COMPA'W OCONEE UNIT 3 Report Number: R0-287/78-15 Report Date: December 8, 1978 Occurrence Date: July 31, 1978 Facility: Oconee Unit 3, Seneca South Carolina Identification of Occurrence: RPS Channel A RC Flow Indication Non-Conservative Conditions Prior to Occurrence: 88% Full Power Description of Occurrence:
On July 29, 1978 during the performance of the Instrument Surveillance Check (PT/0/A/0600/1) on Unit 3, it was determined that the reactor 6
indication on RPS Channel A was reading approximately 17 x 10 lb/hr higher than channels B, C, and D.
OnJulygl,1978,itwasnotedbyoperators that the channel was reading 33 x 10 lb/hr high. The channel was placed in manual bypass at 0825 on July 31.
Personnel investigating the anomalous readings entered the Reactor Building and found a leak on the instrument's impulse line. Attempts to temporarily repair the line were not successful.
On August 1,1978 the leaking fittings were replaced, but the channel was left in bypass to prevent a spurious trip of the remaining RPS channels which could accompany attempts to valve Channel A back into service. On November 7,1978, the channel was returned to service during a unit outage and during a review of the shif t supervisor's log, it was determined that this incident was reportable pursuant to Oconee Technical Specifications 6.6.2.1.b(1).
Cause of Occurrence:
The anomalous RC flow indication of RPS Channel A was caused by leakage from the impulse line.
Analysis of Occurrence:
RPS Channels B, C, and D were operable *throughout the occurrence. The RPS would have tripped on 2-out-of-3 logic which assures the functional capability of the RPS.
This incident did not reduce the effectiveness of the RPS, and there were no adverse ef fects on public health and safety.
Corrective Action:
J On August 1,1978 the leaking fittings were replaced. On November 7, 1978 the i
transmitter was calibrated and placed into service. A procedural change was written on October 26, 1978 which specifies actions to be taken in specific cases of RPS and ES channel inoperability depending on the number of redundant channels available.
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