ML20086G894
| ML20086G894 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/12/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086G898 | List: |
| References | |
| AO-75-31, NUDOCS 8401120581 | |
| Download: ML20086G894 (2) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 3'If},,
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PHILADELPHIA PA.19101 D, f;@h h) d
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Mr. A. Giambusso N_ : &
Director Division of Reactor Licensing Of fice of Nuclear Reactor Regulations United States Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Giambusso:
Subject:
_Abnorma l Occurrence A
The following occurrence was reported to Mr. Walt Baunack, Region 1, Office of Inspectio'n and Enforcement, United States Nuclear Regulatory Commission on June 3,1975 Written notification was made l
to Mr. James P. O'Reilly, Region 1, Of fice of Inspection and Enforcement, United States Nuclear Regulatory Comrnission on June 3,1975 In 1
accordance with Section 6 7.2.A of the Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following is being submitted to the Directorate of Reactor Licensing occurrence as an Abnormal Occt.rrence.
Reference:
License Number DPR-56.
Technical' Specification
Reference:
4.7.D s
Repor t No. :
50-278-75-31 Report Date:
June 12, 1975 Occurrence Date:
June 2, 1975 Facility:
Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314
_ Identification of Occurrence:
Failure of the
'B' TIP machine ball valve to close.
9 Conditions Prior to Occurrence:
Unit 3 at 50% power.
COPY SENT REGION Description of Occurrence:
During routir.c operation of the TIP machines, the 'B' detector f ailed to stop at the shicid limit and close the ball valve as it was being withdrawn into the shield chamber.
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Mr. A. Giambusso 50-278-75-31 June 12, 1975 Page 2 Designation of Apparent Cause of Occurrence:
The shield limit switch, which controls detector travel and ball 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 manual ly stopped.
Analysis of Occurrence:
The failure of the limit switch to halt the withdrawal and close the bail valve was immediately observed and corrected by switching to the manual mode of operation to stop the machine. The ability to close the ball valve by turning the machine off (de-energi ze to c lose) was verified. Therefore, there are no safety implications to this occurrence.
Corrective Action:
The detector was returned to its proper in-shield position.
The machine was de-energized and the ball valve was verified to be closed.
Investigation reveal,cd that dirt had entered the shield limit switch mechanism causing it to bind.
The mechanism was cleaned and re-assembled and the TIP was operated successfully several times.
Failuro Data:
No previous failures of this type.
Very truly yours,
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s' M.
. Cooney Ass' t Gen' t Superintendent Generation Division cc:
Mr. J. P. O 'Rei l l y Director, Region 1 Office of Inspection and Enforcement United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 I
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