ML20084L550

AO 50-237/1974-40:on 740815,during Routine Instrument Surveillance,Hpci Pressure Switches Ps 2389 a & B Found W/ Setpoints Out of Calibr.Caused by Setpoint Drift.Switches Reset.Switch Will Be Replaced

ML20084L550
Person / Time
Site:	Dresden
Issue date:	08/23/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084L552	List: ML20084L550 ML20084L558
References
614-74, NUDOCS 8305230365
Download: ML20084L550 (1)

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Addrsss Fisp[y to: Post Othee Box 767 Chicago. tilinois 60690 BBS Ltr.#614-74 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 -- ,

August 23, 1974 /h).id 3

s k 9 0.J Mr. James G. Keppler, Regional Director AUG281974 > -

Directorate of Regulatory Operations-Region III $ 111 AH:: Em o U. S. Atomic Energy Commission 799 Roosevelt Road 8$.7 M Scuta

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Glen Ellyn, Illinois 60137 4 ,

SUBJECT:

REPORT OF ABNORMAL OCCURRENCE PER SECTION 6.6.B OF THE TECHNICAL SPECIFICATIONS.

SETPOINT DRIFT OF HPCI TURBINE TRIP PRESSURE SWITCH.

References:

1) Regulatory Guide 1.16 Rev.1 Appendix A

2) Notification of Region III of AEC Regulatory Operations Telephone: Mr. F. Maura,1450 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.51725e-4 months <br /> on August 16, 1974 4 Telegram: Mr. J. Keppler,1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on August 16, 1974 Report Number: 50-237/1974-40 Report Date: August 23, 1974 Occurrence Date: August 15, 1974 Facility: Dresden Nuclear Power Station, Morris, Illinois JD,EJfrIFICATION D OF OCCURRE_NCE High pressure coolant injection (HPCI) pressure switches P3 2389 A&B were found with setpoints which would not allow HPCI operability at

.2. 90 psi reactor pressure as required by the Technical SpecAfications.

CONDITIONS PR_IOR TO OCCURRENCE At the time of the occurrence, Dresden Unit 2 was operating at '

a steady load of 610 HWe .with routine instrument surveillance in progress.

DESCRIPTION OF OCCURRENCE ,

1 Pressure switches PS 2389 A&B were found with reset points of 94 psi and 93 psi respectively. The switch function-is to trip the HPCI turbine

'on low reactor pressure. The switches then must reset- to allow HPCI opera-bility. The conditions ~ found on August 15, 1974 would have prevented the HPCI turbine from resetting until a reactor pressure of 93 psi was attained.

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