ML20086J325
| ML20086J325 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/31/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086J326 | List: |
| References | |
| AO-74-17, NUDOCS 8401230574 | |
| Download: ML20086J325 (2) | |
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October 31, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Cocmission Directorate of Licensing Washington, DC 20545
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region 1 Regulatory Opu 2tions Office on October 22, 1974.
Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Of fice on October 22, 1974.
In accordance with e
Section 6.7 2.A of the Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the'following report is being submitted to the Directorate of Licer. sing as an Abnormal Occurrence.
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Reference:
License Number DPR-56 Technical Specification Reference 3 5.B Report No.:
50-278-74-17 Report Date:
October 31, 1974 Occurrence Date:
October 21, 1974 Facility:
Peach Bottom Atomic Power Station R. D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:
Inoperable HPSW valve M0-3-10-898.
Conditions Prior to Occurrence:
Reactor pressurized to 900 psig, turbine off.
Description of Occurrence:
While attempting to open the valve to perform routine stem i
repacking, the motor operator circuit breaker tripped on instantaneous overcurrent.
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'g' Mr. A. Gicmbusso 0ctober 31, 1974 Page 2 Designation of Apoarent Cause of Occurrence:
Investigation indicated a mechanical failure of the valve-open limit switch, which permitted the motor to remain energized af ter the valve had reached a full open, back seated condition. After a short period of time in a stalled condition, the motor failed electrically and tripped the circuit breaker.
The limit switch malfunction was caused by the loosening of the bolts that attach the switch stationary contact block to the opera-tor housing. The loosening was probably caused by valve vibration, and resulted in dis-engagement of the limit switches stationary and movable contacts.
Analysis of Occurrence:
With one HPSW valve out of service; both LPCI loops, four HPSW pumps, and three RHR heat exchangers are operable. Therefore, the safety significance is minimal.
Corrective Action:
t The motor has been removed and is being rewound according to C
an approved procedure. The switch assembly was re-installed using Loctite coated bolts to prevent a recurrence of the malfunction. The other seven HPSW control valves were inspected and upgraded by the application of Loctite to their switch mounting bolts.
O Failure Data:
There is no record of a similar HPSW valve motor operator failure.
Very truly yours, WY
. Jr Cooney Ass Gen' t Superintendent Generation Division
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Mr. J. P. O'Reilly
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Director, Region i United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406-e S
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