ML20084R517

AO 50-249/75-15:on 750310,during Routine Surveillance of Pressure Switch PS3-263-52A-2,setpoint Found Below Tech Spec Limits.Caused by Inherent Setpoint Drift.Switch Trip Point Reset

ML20084R517
Person / Time
Site:	Dresden
Issue date:	03/20/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
172-75, AO-50-249-75-15, RO-50-249-75-15, NUDOCS 8306150153
Download: ML20084R517 (2)

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-~s vusseijiUiiVaane auime f E3/ one First t'ational Plaza. Chicago tilinois

- Q.p'< Addres ty to: Post Olhes Box 767

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nois 60690

~ Chicag D'BS Ltr. #172-75 Dresden Nuclear Power Station R.R. #1 Morria, IL 60450 March 20, 1975

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/nmes G. Keppler ' U.

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Regional Director Directorate of Regulatory Operations - Region III 'T[k /'"  ;

U.S. Nuclear Regulatory Comission 799 Roosevelt Road g",%.h fj..,,, ,

y O N Glen Ellyn, IL 60137

SUBJECT:

REPORT OF AFNOP2ML OCCURRB'CE PER SECTION 6.6.A OF THE TDCHNICAL SPECIFICliTIC::S LICI F~r?f4IS$5YT: PREe3UEE SITIT"H DRIFT

References:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) Notification of Region III of U.S. Nuclear Regulatory Comission

. S' ' ' " -2 Telephone: P. Johnson,1400 hrs, 3/11/75

,, Telegram J. Keppler, 1545 hra, 3/11/75 c >

3) h* awing thaber: M-26, 12E2437 ,

Report Number:. 50-249/75-15

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Report Date: March,20, 1975 Occurrence Date: March 10, 1975

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Facility:- Dresden Nuclear Power Station, Morris, IL 60450

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IDENTIFICATION OF OCCURRENCE Dresden Unit 3 Core Spray Permissive Pressure Switch Setpoint Technical Specification violation. Following NRC 24 hour notification it was discovered that an error had been cado in reporting the Equipment Prico Number for this switch. The suitch which failed was P,53-263-52A-2 as opposed to PS3-263-52A-1 as initially reported.

CONDITION PRIOR TO OCCURRENCE At the time of the occurre'nce Dresden Unit 3 was operating st 404 M' ument surveillanco in progress.

J e with instr- -f DESCRIPTION OF OCCURRENCE l

During routine scheduled surveillance of pressure switch PS3 263-52A-2, its sotpoint was found to be 270 pois decreasing, which is below the specified Technical Specification Limit of 300 to 350 pais decreasina. The switch uas inspected and no anomalica were noted. The owitch was imediately recet to  ;

324 psis. l 830615015305000249 750320 $$

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March 20, 1975

• • Jazcas 0. Keppler O pQ LJ .

DESIGNATION OF APPARP.T Cf.USE CCCURRD'CE (PCUIP52T I 1herent setpoint' drift, sdlich has The cause of this occurrence appears to bo 1: l been a recurring problem with bourdon tube pressure switches.

ANALYSIS OF OCCURRD'CR PS3-263-52A-2 is one of .two switches that PS3-263-52B-2 The other switch, monitor reactorwas pressure a a permissivo for core spray injection. Due to the (

i found with a setpoint of 322 psig, which was within limits.

redundancy of the cwitches, core spray initiation would have occurred, if i nocded, at 322 psig, which is above the 300 psig Technic minimum.

the general public was not jeopardized as a result of this occurrence.

CORRFr,TIVE DATA The long The ir=nediato corrective action was to resot tho snritch trip point.

td rango correctivo action will be to replace the switch date of replacement will be approximately ono year. .

FAILURE DATA f The switch was last found out of Technical Specification TAmit in Sept The suitch is a Meletron Model 372 vith a.rance of 28 to 12:00 psig.

1972.

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B'. ' . Stephenson Superiittcndent Dresden Nuclear Power Station 1.;

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