ML20086G879
| ML20086G879 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/20/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20086G881 | List: |
| References | |
| AO-75-34, NUDOCS 8401120557 | |
| Download: ML20086G879 (2) | |
Text
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I PHILADELPHIA ELECTRIC COMPANY 23O1 MARKET STREET fu '
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PHILADELPHIA. PA.19101
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June 20, 1975 Y,,
Mr. A. Giambusso
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Division of Reactor Licensing Office of Nuclear Reactor Regulations United States Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Giambusso:
Subject:
Abnc: mal Occurrence The following occurrence was reported to fir. Walt Baunack, Region 1, Office of Inspection and Enforcement, Uni ted St ates Nuc lear Regulatory Commission on June 12, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1, Office of Inspection and Enforcement, United States Nucicar Regulatory Commission on June 12, IS'5 In accordance wi th Section 6.7. 2. A of the Technical Speci fica-tions, Appendix A of DPR-56 for Unit 3 Peach Dottom Atomic Power S t a t i on, the following occurrence is being submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-56 Technical Specification
Reference:
4.7.D Report No. :
50-278-75-34 Report Date:
June 20, 1975 Occurrence Date:
June 11, 1975 Facility:
Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17,314 Identification of Occurrence:
Failure of the "C" TIP machine ball valve to close.
Conditions Prior to Occurrence:
Unit 3 at 50% power.
e Description of Occurrence:
During routine operation of the TIP machines, the "C" detector failed to stop at the shield chamber.
8401120557 750620 PDR ADOCK 05000278 oen
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I cran itEGION '
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50-278-75-34 lir. A. G i ambus/~'
June 20, 1975 \\
Page 2 Designation of Apparent Cause of Occurrence:
c The shield limit switch, which controls detector travel and bs11 valve operation, failed to operate when.the detector reached the "in shield" position. This allowed the detector to continue its with-drawal until it was manually stopped.
{nalysis of Occurrence:
The failure of the limit switch to halt the withdrawal and close the ball valve was int.ediately observed and corrected by switch-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) was verified and would have been available if required.
Therefore, there are no safety implications to this occurrence.
Corrective Action:
The detector was returned to its in-shield position.
The machine was de-energized, and the ball valve was verified to be closed.
The shield limit switch mechanism was dismantled, inspected, found to be clean and free of binding, reassembled, and adjusted for optimum switch operation.
The switch was then functionally tested several times.
Fai lure Data:
One previous failure of this type reported in 50-278-75-31.
Very truly yours, f f%& h f M. A. Cooney f
A s't Gen' t Superintendent Generation Division ec:
Mr. J. P. O'Rei l ly
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Director, Region 1 Office of Inspection and Enforcement United States !!ucicar Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 t
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