ML20086H722
| ML20086H722 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/27/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20086H725 | List: |
| References | |
| AO-75-48, NUDOCS 8401200143 | |
| Download: ML20086H722 (2) | |
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,e.2 June 27, 1975 Mr. A. Giambusso, Director Division of Reactor Licensing Office of Nuclear Reactor Regulations Unitec' States Nuclear, Regulatory Corrmi ssion Wshington, D. C.
20555
Dear Mr. Giambusso:
SUBJECT:
Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, Region 1,
- Office of Inspection and Enforcement, thited States Nuclear Regulatory Commi,ssion on June 20, 1975 W*itten notification was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, United States Nuclear Regulatory Commi ssion on June 20, 1975 In accordance with Section 6 7 2.A of the Technical Specifications, Appendix A of OPR-44 for Uni t 2 Peach Bottom Atomic Power Station, the following occurrence is being submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-44 Technical Specification
Reference:
3.6.D.1, 3 7.D.1 Repor.t No.:
50-277-75-48 Report Date:
June 20, 1975 Occurrence Date:
June 19, 1975 Facili ty:
Peach Bottom Atomic Power Station RD 1, Delta, Pennsylvania 17314 Identification of Occurrence:
Relief valve (71K) opened causing reactor depressurization.
Conditions Prior to Occurrence:
Reactor shutdown. Reactor pressure app'roximately 600 psig.
Description of Occurrence:
Approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> before this occurrence, relief valve 71K had been operated for 3 ten second periods to control reactor pressure following a main steam line isolation which was associated with the unit tripping caused by a lightning strike on the outgoing substation. The valve spuriously opened at 11:15 pm.
The valve closed at 11:28 pn with reactor pressure at approximately 200 psig.
8401200143 750627 gDR ADOCK OSOM277 7211 PDR L
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50-277-75-48 Mr. A. G i ambus sa Page 2 June 27, 1975
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Designation of Apparent Cause of Occurrence:
The air solenoid valve was found to be partially open. Also, bench testing showed excessive self-actuating pilot seat leakage.
The partial opening of the solenoid valve could have been, but is not thought to be, the cause. Excessive leakage of the self-actuating pilot would ". ave pressuri zed the second stage piston, resulting in valve actuation.
Analysis of Occurrence:
An analysis of the temperature transient associated with the occurrence showed that no reactor vessel temperature limits were exceeded with cooldown rate less than 100 F/hr. Torus water temperature rose to a maximum of 116 F.
' Based on the temperature analysis there is minimal safety significance attached to this event.
Corrective Action:
The leaking pilot valve was lapped, leak tested and returned to service.
Failure Data:
Previously reported Abnormal Occurrences concerning Unit 2 relief valves were report numbers 50-277-74-12, 50-277-74-16, 50-277 17, and 50-277-74-44.
Very truly yours, M.
. Cooney Ass't Gen't Superintendent Generation Division cc:
Mr. J. P. O'Reilly Director, Region i Of fice of Inspection and Enforcement United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 r
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