ML20086J141
| ML20086J141 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/20/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086J144 | List: |
| References | |
| AO-74-36, NUDOCS 8401230246 | |
| Download: ML20086J141 (2) | |
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PHILADELPHIA ELECTRIC COMPANY
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December 20, 1974 l
Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing f,
Washington, DC 20545 i
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Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, b
A.E.C. Region 1 Regulatory Operations Offise on December 10, 1974.
Written notification was made to Mr. James P. O'Rei1ly, Region 1 Regu-latory Operations Office on December 10, 1974.
In accordance with Section 6.7 2.A of the Technical Speci fications, Appendix A of OPR-56 for Unit 3 Pctch Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.
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Reference:
License Number DPR-56 Technical Specification
Reference:
3 5.8 Report No.:
50-278-74-36 Report Date:
December 20, 1974 Occurrence Date:
December 10, 1974 Facility:
Peach Bottom Atomic Power Station R. D. /il, Delta, Pennsylvania 17314 Identification of Occurrence:
Failure of limitorque motor support-on HPSW/RHR heat. exchanger
_ discharge valve MO-3-10-83A.
C_onditions Prior to Occurrence:'
Unit shutdown. RHR shutdown - cooling mode in service.
Description of Occurrence:
During the operation of valve MO-3-10189A in connection with placing the RHR and HPSW system in service to cool the primary system with the reactor. shutdown, the subject valve motor support f ailed. The valve at this-time was-in a throttled position.
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Mr. A. Giambusso December 20, 1974 I
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Designation of Apparent Cause of Occurrence:
During operation these valves are subject to vibration. The cap screws which hold the limitorque motor operator to an adapter plate were found to be broken.
Analysis of Occurrence:
The f ailure of the cap screws render the valve inoperable.
In this case the valve failed in a partially throttled position but very close to full open. Adequate decay heat removal capability was available using the other RHR heat exchangers.
Investigation revealed that the valve stem was bent. Pending arrival of a new stem, the operator was reinstalled and the valve manually throttled to provide the correct HPCW flow.
Once the correct flow was obtained, tnc oper a-tor handwheel was chained and locked in position. With all four con-tainment cooling subsystem loops availabic, a plant startup was initi-ated. Minimal safety significance is attached to this failure.
Corrective Action:
The valve will be disassembled for a canplete internal in-spection, and the stem straightened or replaced. The motor will be re-moved and tested. The operator will be remounted using high tensile strength cap screws, and secured with LOC-TITE.
Inspection of the re-maining valves in the same service is in progress. The Philadelphia Electric Company, Mcchanical Engineering Division in concert with the Architect Engineer is investigating means of reducing vibration on this system.
Failure Data:
Similar dif ficulties have been reported as Abnormal Occurrence Report Numbers 50-277-74-53, 50-278-74-28 and 50-278-74-35 Very truly yours, f,- f),/,ff w f R. D. Meycr General Superintendent Generation Division cc:
Mr. J. P. O'Reilly Director, Region i U. S. Atomic Energy Commissi'n o
631 Park Avenue King of Prussia, PA 19406 t
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