ML20073R084
| ML20073R084 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/30/1983 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| RO-82-176, NUDOCS 8305030432 | |
| Download: ML20073R084 (2) | |
Text
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YED Southern California Edison Company W U2,,,,
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$4N C LEMEN T E, C A LIFORNt a 92672 H. 8. R A Y TELEPHONE March 30, 1983 imn "a i u v io N o.N... R U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Regicn V 1450 Maria Lane, suite 210 Walnut Creek, California 94596-5368 Attention:
Mr.
R. H. Engelken, Regional Administrator
Dear Sir:
Subject:
Docket No, 50-361 Prompt Report Licensee Event Report No.82-176 San Onofre Nuclear Generating Station, Unit 2 Pursuant to Section 6.9.1.12.b of Appendix A, Technical Specifications to Facility Operating License NPP-10 for San Onofre, Unit 2, this submittal provides the written confirmation of our March 29, 1983 prompt notification to the NRC for a reportable occurence involving the Reactor Protection System (RPS).
As a result of the failures of coactor Trip Circuit Breakers (TCB's) reported in LER 83-019 (Docket 50-361) and LER 83-023 (Docket 50-362), a review of past Work Orders and Non-Conformance Reports (NCR's) was performed.
Based on this review, it has been determined that on July 10, 1982, due to failure of TCB's 4, 6 and 7 to latch, maintenance was performed which included adjustment of the undervoltage trip mechanism.
Subsequently, a functional test of the TCB's was performed to demonstrate they would trip and they were returned to service.
The functional test did not independently verify operability of the undervoltage trip mechanism and, following additional TCB maintenance on July 12, surveillance testing of all TCB's was performed which identified that the undervoltage trip mechanism for TCB's 4 and 7 was not operable although the shunt trip mechanism was operable.
Following the functional test, and prior to the subsequent surveillance test, the Control Element Assemblies (CEA's) drive system was capable of CEA withdrawal and fuel was in the reactor vessel.
Failure to independently verify operability of the i
undervoltage trip mechanism following maintenance on July 10, 1982, resulted in a condition less conservative than the least conservative aspects of LCO 3.3.1 and its associated Action Statements.
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R. H. Engelken March 30, 1983
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The 14-day follow-up report with a copy of Licensee Event Report i
(LER)82-176 will be submitted by April 12, 1983 to address this event, including corrective actions and measures to prevent recurrence.
If you have any questions regarding the above, please contact me.
Sincerely,
/b6bl l
cc:
A.
E. Chaffee (USNRC Resident Inspector, Units 2 & 3)
R.J. Pate (USNRC Resident Inspector, Units 2 & 3)
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