ML20086J261
| ML20086J261 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/16/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-74-21, NUDOCS 8401230531 | |
| Download: ML20086J261 (2) | |
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November 16, 1974 Mr. A. Giambusso p.,
Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545
Dear Mr. Giambusso:
Subject:
Abr,ormal Occurrence The following occurrence was reported to Mr. Walt Baunack, A.E.C. Region 1 Regulatory Operations Office on November 7,1974.
Written notification was made to Mr. James P. O'Reilly, Region 1 Regu-latory Operations Office on November 7, 1974.
In accordance with Section 6.7.2.A of tne Technical Specifications, Appendix A of DPR-56 for Unit 3 Peach Bottom Atomic Power Station, the following report.is being submitted to the Directorate of Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-56 Technical Specification Reference Table 3 2.B Repor t No.:
50-278-74-21 Report Date:
November 16, 1974 Occurrence Date: November 6, 1974 Facility:
Peach Bottom Atomic Power Station R.D. #1, Del ta, Pennsylvania 17314 Identification of Occurrence:
Setpoint shif ts on RCIC Steam Line Hi Flow isolation switches, dPIS-3-13-83 and dPIS-3-13-84.
Conditions Prior to Occurrence:
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Plant at 68% power.
Description of Occurrence:
During routine instrumant surveillance testing, dPIS-3-13-83 was found to trip at 475 inches H O differential and 463 inches H O 2
2 differential on switches 1 and 3 respectively and dPIS-3-13-84 was afd-bg$
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. Nov:mber 16, 1974 Page 2 found to trip at 487 inches H O dif ferential-on switch I. The Technical 2
Specification. limit is f 450 inches H O dif ferential.
2 Designation of Apparent Cause of Occurrence:
Setpoint shift.
Analysis of Occurrence:
Even though the setpoints as found on each of these switches were in excess of the Technical Specification limit of 450 inches H O 2
differential, the calculated 300% flow differential pressure was approxi-mately 600 inches H 0.
These switches still would have operated well 2
below the actual design limi t, therefore, the safety implications are minimal.
Corrective Action:
Investigation revealed that the setpoint shift was caused by a factory adjustment which allowed the switch actuating arm to operate on the knee of the actuation cara. This made the setpoir.t adjustment very sensitive and the actuator travel very short. The switches.were aligned in accordance with an approved procedura, reset and checked for proper calibration per the applicabic surveillance test.
Failure Data:
No previous similar failures of this type device in this service.
Vegy truly yours, 1 -)
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. Cooney3 As
't Gen't uperintendent
. Generation Division cc:
Mr. J. P. 0'Reilly Director, Region i United States Atomic Energy Commission 631 Park Avenue
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