ML20086K592
| ML20086K592 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/25/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-74-52, NUDOCS 8401270330 | |
| Download: ML20086K592 (2) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET PHILADELPHI A. PA.19101 e-
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12:s 8414ooo November 25, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, DC 20545
Dear Mr. Giambosso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Paul Nelson, A.E.C. Region i Regulatory Operations Office on November 16, 1974.
Written notification was made to Mr. James P. O'Reilly, Region i Regu-latory Operations Office on November 18, 1974.
In accordance with Section 6 7 2.A of the Technical Specifications, Appendix A of DPR-44, for Unit 2 Peach. Bottom Atomic Power Station, the following report is t
being submitted to the Directorate of Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-44, Amendment Number 1 Technical Specification
Reference:
Table 3 2.8 Report No.:
50-277-74-52 Report Date:
November 25, 1974 Occurrence Date:
November 15, 1974
-Facility:
Peach Bottom Atomic Power Station 1
R.D. 1, Delta, Pennsylvania 17314
_ Identification of' Occurrence:
Setpoint shift on RHR loop selection Jet Pump RiserAp switches dPIS-2-2-129A and dPIS-2-2-129C.
Conditions Prior to Occurrence:
Unit 2 operating near. full power.
Description of Occurrence:
During routine instrument surveillance testing, dPIS-2-2-129A was found in the tripped condition and would not reset when equalized.
' By applying a 'dif ferential in the opposite direction, the switch was
. found to reset at -l.1 and to trip at -0 5 psid. dPIS-2-2-129C was found to trip at 0.25 psid. The Technical Specification limit is +0 5
<p51 5 psid 12073 8401270330741125 PDR ADOCK 05000277 S
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Page 2 Desionation of Accarent Cause of Occurrence:
Setpoint shift partially attributable to component wear.
Analysis of Occurrence:
Even thcagh both switches in the 'A' logic for selection of the proper recirc loop for RHR (LPCI) injection were outside of the Technical Specification limits, dPIS-2-2-129C would still have correctly sensed the direction of dp and allowed f er the correct selection of a recirc loop for LPCI injection. Therefore, the safety implications of thi s setpoint shift are not significant.
Corrective Action:
dPIS-2-2-129-B and D were tested and found to be fully opera-tional. Preliminary investigation yielded two findings:
1, the set-point shift was aggravated by a factory adjustment which allowed the switch actuating arm to eperate on the knee of the actuation cam.
This made the setpoint adjustment very sensitive and the actuator travel very short; 2, the roller on the switch actuating arm was found to have worn slightly on the ' A' switch. The switch actuating arm was replaced, the switches aligned in accordance with an approved procedure, reset and checked for proper calibration per the applicable surveillance test.
Failure Data:
A previous setpoint shift on this device occurred on 12/12/73 and was reported as Abnormal Occurrence 50-277-73-16. A previous find-ing of improper f actory adjustment on this type of device was reported as Abnormal Occurrence 50-278-74-21.
Very truly yours,
, // l (do. g a t..
<M.[s'tGeneral' Superintendent J.
oney Ap Gencretion Division cc:
Mr. J. P. O'Reilly Director, Region I United States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406 l
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