ML20086F966

AO 75-65:on 751015,setpoints on Reactor High Pressure Scram Switches Found Less Conservative than Specified by Tech Specs.Caused by Instrument Setpoint Shift.Channel D Switch Recalibr,Tested & Returned to Svc

ML20086F966
Person / Time
Site:	Peach Bottom
Issue date:	10/24/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Boyd R Office of Nuclear Reactor Regulation
Shared Package
ML20086F969	List: ML20086F966 ML20086F970 ML20086F974
References
AO-75-65, NUDOCS 8401090731
Download: ML20086F966 (2)

Text

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, 6 O PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHI A. PA.19101 nen 12151 841-4o00 ,

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• October 24, 1975 -; , -

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Mr. Roger S. Boyd 'K

Acting Director Nc . i , , . ./

Division of Reactor Licensing Office of Nuclear Reactor Regulations United States Nuclear Regulatory Commission Washington, DC 20555

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 October 15, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1, Office of Inspection and Enforcement, United States Nuclear Regulatory Commission on October 16, 1975 In accordance wi th Section 6.7.2.A of the Technical Speci-fications, Appendix A of DPR-44 for Unit 2 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-44 Technical Specification

Reference:

Table 3 1.1 Report No.: 50-277-75-65 .

Report Date: October 24, 1975 Occurrence Date: Octcber 15, 1975 Facility: Peach Bottom Atomic Power Station R.D.- 1, Delta, Pennsylvania 17314 Identification of Occurrence:

Setpoints of the reactor high pressure scram switches (PS-2 3-55 B, C and D) were f ound to be less conservative than that specified by the Technical Specifications.

Conditions Prior to Occurrence:

Unit 2 at 56% power.

3 Description of Occurrence:

During routine instrument surveillance testing, the "D" reactor high pressure scram switch setpoint was found to be 9 PSI greater than that specified by the Technical Specifications. Subsequent t,estingsof 9401090731 751024 - 42 d PDR ADOCK 05000277 f  !

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t Mr. Roger S. Boyd . 5 77-75-65 October 24, 1975 Page 2 the other three switches revealed that channel "B" was 4 PSI high, channel "C" was 2 PSI high, and channel "A" was within specifications.

, Designation of Accarent Cause of Occurrence:

l Instrument setpoint shift.

Analysis of Occurrence:

Because the setpoint shift was slight (maximum shif t of 9 PSI at a setpoint of 1055 PSIG) and all switches monitoring the reactor i

pressure were verified to be operational, this occurrence has minimal safety implications.

Correcti ve Action:

The channel "D" switch was inmediately recalibrated tested ,

and returned to service. The testing of the remaining channels of I high pressure scram logic was initiated. The other out of specification swi tches were di scovered. These switches were recalibrated, tested and returned to service. An investigation into the calibration history of the pressure ; witches and the accuracy of the test gages revealed no abnormality.

Failure Data:

One previous failure of this type reported in September 1973 1

Very truly yours, 1

M. . Cooney S erintendent Generation Division - Nuclear cc: Mr. J. P. O'Rei lly Director, Region 1 Office of Inspection and Enforcenent United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 G

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