ML20084D432

AO 50-237/75-29:on 750519,limit Switch Indicating 10% Closure on 1C MSIV Failed During Startup.Caused by Failure to Reinstall 1C Limit Switch & to Perform Tests.Switch Reinstalled

ML20084D432
Person / Time
Site:	Dresden, 05000137
Issue date:	05/29/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
331-75, 5981, AO-50-237-75-29, NUDOCS 8304110199
Download: ML20084D432 (3)

Text

Q Chicago, Illinois 60690 r

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BDS Ltr. #331-75 Dronden Nuclear Power Station R. R. #1 Morris, Illinois 60450 May 29, 1975 .x lh> ,

Mr. James G. Keppler, Regional Director I_b .

Directorate of Regulatory Operation-Region III -

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U. S. Nuclear Regulatory Co: mission p ,jdNgo -J 799 Roosevelt Road g mmt TU p#

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Glen Ellyn, Illinois 60137 c, 9.y'$!}$

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SUBJECT:

REPORT OF APNOR'ML OCCURRR!CE PER SECTION 6.6. A 0F THE ' 1D7IGAI b

SPECIFICATI0:S

FAILURE OF MSIV-1C "410% CI4SURE" IE!IT SWITCH

References:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) Notification of Region III of U. S. Nuclear Regulatory Comniosion Telephone Mr. Johncon, 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> on May 20, 1975 Tolegram: Mr. Koppler, 1515 hours0.0175 days <br />0.421 hours <br />0.0025 weeks <br />5.764575e-4 months <br /> on May 20, 1975

3) Drawing Number Electrical Print 12E2464 Report Number: 50-237/75-29 Report Date May 29, 1975 i Occurrence Dator May 19,1975 j

Facility: Dresden Nuclear Pouer Station, Morris, Illinois IDR.'I'IFICATION OP OCCURRE;CE The limit switch indicating " 4~0% closure" on the 10 Main Steam Isolation Valve failed during the startup of Unit-2 following a refueling outage. This event is contrary to section 3 1 of the Tcebnical Specifications.

CONDITIONS PRIOR TO OCCURRD!CE At the time of the occurrence, Unit-2 was in the STARTUP modo at 110 ZGt.

DESCRIPTION OF OCCURRE'CE At 0907 hourn on May 19, 1975, the M31V timing surveillance was started. Whilo testing valve 1A, a channel B half ceram was initiated. Investigation revealed that Reactor Protection Relay 590-102D was do-onorgized. This relay is normally energized through the " 410% closure" limit switches on MSIV's 10 & 2C.

8304110199 750529 PDR ADOCK 05000237 S PDR 5981 _ .

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. Accor. ding to the valve positiontoindicator ligh%o, try and pick up the h590-102D relay. ,

. 10 & 2 C were tested p an attempt  !

testa had no effect o.~the relay. I I

)

. DESIGNATION OF APPARD.T CAUSE OP OCCURRENCE inerted.. Operating (P At the time of this occurrence the dryuell had not yet beenl to check the ope j f the switch wore t personnel and a master mechanic entered the drywel10 g

missing.

itches were removed l During the recent Unit-2 refuelingAll the outage, all switches woreIGIVnatisfactorily limit ow tested forIn 1

for inspection and cleaning. j continuity in the shop after being cleaned. #

installed, tested, y never reinstalled.

• It was assumed by station management that all the owitches wer -

and operating properly.a maintenanceOn fimetional test,the April 17, 1975 two post maintenanco work closure test, and ESIV closure tidng test.However, the two operational tests had not package was signed off as completed.The maintenance h erational foreman test., signed the sa been perforr.ed. re present and package in the location indicating completion of t e op When the work package was cubacquently reviewed, all cignatures we the package was considered complete. First, Soveral procedural problems compounded to resultt perfonced.

in the occurrence.

the maintenence test required on the mritch apparently was no d Eight of these switches were being inspected and tooted during the time period. It is curmined th'tt the tested and untested cwitc test, an error in the maintenance shop.in the location reserved for ithe sign-off of the ope which went unnoticed in subsequent review of the package.ingti cwitch unless opccified tests opecified with the packago would not have revealed the m ss the tests were performed above 600 psig reactor. pressure rolt2yo were observed.above 600 psig reactor pressure, would have indicate i

I t

t ANAINSIS OP OCCURRU!CE lay 590-102D l The absence to drop out.

of the " 410% closure" limit switch i on MSIV '!

)

Since the above failure was to the " fail safo" modo, the design criter i blic were not '

-(three steam lines greator than 10% closed yieThereforo, t jeopardized as a result of thin occurrence.

CORRECTIVE ACTIO!{ d". modo.  ;

tion  !

The unit was operated for four days with the circuil t

verified. .

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To proyent recurrence, this incident will be disci ned with the personnel involved.

' Alto, c descript V ^'of the incident will be distr. ted to all management personnel with emphasis on t.a need to adequately opecify ana review tests to b3 perforced.

Tite corrective action will be completed by June 6, 1975.

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. Stephenson Superintendent BBS: cmp File /IGIC O

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