ML20086L249
| ML20086L249 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 04/03/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086L252 | List: |
| References | |
| 74-15B, AO-74-15A, NUDOCS 8402080002 | |
| Download: ML20086L249 (3) | |
Text
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M April 3, 1974 50 277 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Comission Directorate of Licensing Washington, DC 20545
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. R. A. Feil, A.E.C.
Region I Regulatory Operations Office on March 25, 1974. Written noti-ficcticn was made to Mr. James P. O'Reilly, Region I Regulatory 0,cerations Office on March 25, 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 being submitted to the Directorate of Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-44, Amendment Number 1 A.
Technical Specification Table 3 2.B B.
Technical Specification Table 3 2.A Report No.:
50-277-74-15A and ISB Report Date:
March 25,1974 Occurrence Date:
March 24, 1974 Facility:
Peach Bottom Atomic Power Station R. D. I, Delta, Pennsylvania 17314 Identification of Occurrence:
1 A.
Setpoint shift on dPIS-2-2-129B gp[J' B.
Setpoint shift on TS-2-12-99
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Mr. A. Giambussos s e
April 3, 1974 Pagn 2 Description of Occurrence:
A.
During instrument surveillance testing, dPIS-2-2-129B tripped at 0.45 psid instead of within the Technical Specification i
limits of 0 5 to 1.5 psid.
B.
During instrument surveillance testing, TS-2-12-99 tripped at approximately 142 F instead of within the Technical Speci-fication limit ofsi140 F.
Designation of Apparent Cause of Occurrence:
A.
Inability of this type of switch to hold precise setpoints.
B.
Setpoint drift - possibly the result of the setpoint adjust-ment knob being hit by a wooden skid being handled in the area.
Analysis of Occurrence:
A.
The setpoint shift of dPIS-2-2-1298 would not have defeated the LPCI Loop Selection Logic to produce the required correct loop selection. The remaining switches in this logic were tested and found to be within specifications and would have produced the proper action.
B.
The setpoint shif t of TS-2-12-99 was minor and would not have affected plant or public safety since the purpose of this switch is only to protect the demineralizer resin in the Reactor Water Cleanup System filter-demineralizers from excessive temperatures.
Corrective Action:
Both switches were recalibrated, surveillance. tested, and returned to service.
A.
This differential pressure switch is already part of a group being independently tested to provide better information con-cerning setpoint drifting.
B.
This switch setpoir.: was found to be easily changed. A means of locking the setpoint setting device is being devised and will be installed as soon as it is available.
Failure Data:
A.
This particular switch has no previous history of failure, but this type of switch has failed to hold setpoint seven times previously in various applications. There has been a failure of a companion switch also due to setpoint shift.
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Mr. A. Giambusso Apri1 3, 1974 Page 3 B.
This^ temperature switch has been found to be tripping outside of specs previously, but that failure was found to be due to setting the switch too close to the desired limit. The pre-viously reported setpoint shift was found to be within the accuracy of the instrument.
i Very truly yours,
/j(Atwe M. J. Cooney Ass't Gen'1 Superintendent Generation Division cc:
Mr. J. P. O'Reilly Director, Region 1 United States Atomic Energy Conunission 631 Park Avenue King of Prussia, PA 19406 I
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