ML20086K928
| ML20086K928 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/08/1974 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086K932 | List: |
| References | |
| AO-74-6, NUDOCS 8402070079 | |
| Download: ML20086K928 (2) | |
Text
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I en March 8, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects United Statqs Atomic Energy Comission Directorate of Licensing Washington, D.C.
20545
Dear Mr. Giambus ':
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. R. A. Feil, A.E.C. Region I Regulatory Operations Office on March 1, 1974. Written notification was made to Mr. James P. O'Reilly, A.E.C. Region I Regulatory Operations Of fice on March 1,1974.
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, Technical Specifications Table 3 2.8 Report No.:
50-277-74-6 Report Date:
3/1/74 Occurrence Date:
2/28/74 Facility:
Peach Bottom Atomic Power Station - Unit 2 R. D. 1, Delta, Pennsylvania 17314 Identification of Occurrence:
Setpoint on LIS-2-2-3-1018 which provides a Reactor High Water Level turbine trip input to the HPCI and the Reactor Feed Pump Turbine trip logics shifted.
Conditions Prior to Occurrence:
l Reactor was critical at approximately 34% power and stable.
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Description of Occurrence:
During instrument surveillance testing, LIS-2-2-3-IO18, switch
- 3 tripped at approximately 46 5" Reactor Level instead of f 45" Reactor Level as specified in the Technical Specifications.
Designation of Apparent Cause of Occurrence:
This type of differential pressure switch has shown a repeated.
inability to hold a precise setpoint within the tolerance as specified by the manufacturer. The operating point of the switch shifts slightly between test intervals.
Analysis of Occurrence:
The setpoint shif ts of the' subject switches would not nave de-feated the logic to produce the required safety actions. The other oper-able switches would have caused trips at the proper setpoints. These setpoint shifts were minor and have no safety implications.
Corrective Action:
LIS-2-2-3-1018, switch #3 was reset to the proper value and functionally and calibration checked per the applicable instrument sur-veillance test. Investigation by the Philadelphia Electric Company Engineering & Research Department is continuing. An accelerated testing frequency'has been established.
Failure Data:
These differential pressure switches have required frequent re-calibrations to correct setpoint shifts.
During the past 27 weeks setpoint shif ts have required recalibration on 20 occasions.. Shifts to values in excess of Technical Specification limits occurred five times including this occurrence. Most of these deviations were only slightly above the reouired setpoint and did not constitute a safety hazard.
Very truly yours,
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fYf Klf M. J. Cooney As's't Gen't 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
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