ML20086H618
| ML20086H618 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/24/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| References | |
| AO-75-41, NUDOCS 8401180178 | |
| Download: ML20086H618 (2) | |
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PHILADELPHIA ELECTRIC COMPANY
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.2 July 24, 1975
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Mr. A. Giambusso
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r Director Division of Reactor Licensing Of fice of Nuclear Reactor Regulations
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United States Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Walt Baunack, Region 1, Office of Inspection and Enforcement, United States Nuclear Regulatory Commission on July 14, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1, Office of Inspection and Enforcement, United St ates Nuclear Regulatory Commission on July 15, 1975 In accordance With Section 6.7.2.A of the Technic 61 Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-56
'. Technical Specification
Reference:
Table 3 2.A
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Report Date:
50-278-75-41 Report No.1
' July 24, 1975 Occurrence Dcte:
July 14, 1975
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Facility:
Peach Bottom Atomic Power Station R. D.' 1, Delta, PA 17314 Identificatibn of Occurrence:
Setpoint shift of t;ic main steas fine high flow switch DPIS-3-2-119?.
Conditions Prior to Occurrence:
Unit 3 at approximately t,0%, power.
Description of Occurrence:
During a routinc instrument surveillance test, DPIS-3-2-119D,
setpoint was found to be slightly higher than that specified in the
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Technical Specifications. Recalibration brought the setpoint within r7 '
the specified range, but the repeatability was poor.
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50-278-75-41 July 24, 1975 Pcg2 2 Designation of Apparent Cause of Occurrence:
The retaining screw that fastens the differential drive arm to the actuating cam was loose. This allowed a random differential movement to exist between the instrument s internal parts which re-3 sulted in the setpoint shif t and poor repeatability.
Analysis of Occurrence:
Because the setpoint shif t was slight and this switch operates in a one-out-of-two twice logic, the safety implications of this occur-l rence are minimal.
Corrective Action:
The retaining screw was tightened and coated wi th Glyptol.
The switch was then recalibrated and checked in accordance with the applicable surveillance test.
Failure Data:
Previous failures to trip during surveillance testing were reported as 50-278-75-23 and 50-278-74-33.
Very truly yours, W
H.
Cooney As Gen 1. Su Generation Division l
cc:
Mr. J. P. Orgej i ty Di rector, Region 1 Office of Inspection and Enforcement United States Nuc1 car Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 l
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