ML20086H587
| ML20086H587 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/29/1975 |
| From: | Meyer R PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Boyd R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20086H592 | List: |
| References | |
| AO-75-53, NUDOCS 8401180053 | |
| Download: ML20086H587 (2) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET. STREET PHILADELPHI A. PA.19101 (2151 841 4 o0o t
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August 29, 1975
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Mr. Roger S. Boyd, Acting Di rector Division of Reactor Licensing Office of Nuclear Reactor Regulations Unit %d States Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Boyd:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, Region 1, Of fice of Inspection and Enforcement, United States Nuclear Regulatory Commission, on August 20, 1975 Wri tten notification was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, United States Nuclear Regulatory Commission on August 20, 1975. In accordance wi th Section 6.7.2.A of the Technical Speci fi-cations, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following report is being submi tted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Numbcr DPR-56 Technical Speci ficationn
Reference:
4.7.0 Report No.:
50-278-75-53 l
Report Date:
August 29, 1975 l
Occurrence Date: August 20, 1975 l
Faci li ty:
Peach Bottom Atomic Power Station R.D. #1, Delta, Pennsylvania 17314 Identi fication of Occurrence:
l Failure of the "A" TIP machine ball valve to close.
f Condi tions Prior to Occurrence:
Unit 3 at 55% power.
D_escription of Occurrence:
l f
During routine operation of the TIP machines, the "A" de-l, tector failed to stop at the shield limit and close the ball valve as l
it was being wi thdrawn to the shield chamber.
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8401180053 750829 COPY SENT LEGION l
PDR ADOCK 05000278
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50-278-75-53 Mr. Rogar' S. Bay August 29, 1975 Page 2 I
Designation of Apparent Cause of Occurrence:
q The shield limit switch, which controls detector travel and ball valve operation, failed to operate when the detector reached the
'in-shield' posi tion.
This allowed the detector to continue its withdrawal until it was manually stopped.
Analysis of Occurrence:
The failure of the limit switch to halt the withdrawal and close the ball valve was immediately observed and corrected by swi tch-ing to the manual mode of operation and stopping the machine. The ability to' close the ball valve by turning the machine off (de-energize to close) has been verified and would have been available if required.
Therefore, there are no safety implications to this occurrence.
Corrective Action:
The detector was re-inserted past the shield chamber and the normal withdrawal mode of operation was initiated. The shield limit switch functioned correctly; the detector stopped, and the ball valve closed. The switch was tested several times in this manner.
Each test was successful. The limi t swi tch wa s inspected and a grey powder like substance, believed to be the TIP drive cable lubricant, was found in the~ actuating parts. The swi tch was cleaned, reassembled and tested successfully.
Failuro Data:
. Previous failures of this type were reported as 50-278-75-31, 50-278-75-34, and 50-278-75-42.
Very truly yours, p
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f_] '.l(L ' l' R. D. Meyer General Superintendent Genera tion Di vision cc:
Mr. J. P. O'Reilly, Director, Region 1 Office of Inspection and Enforcement United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 4
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