ML20055H796

Advises of Change to Preventive Maint Program for Electromatic Relief Valves.Rebuild Schedule Will Be Modified to Require Rebuilding Two or Three Valves During Refueling Outage & Remaining Valves During Next Refueling Outage

ML20055H796
Person / Time
Site:	Oyster Creek
Issue date:	07/20/1990
From:	Fitzpatrick E GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9007300090
Download: ML20055H796 (2)

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_ OPU Nuoleer Corporation :

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' Forked River, New Jersey 08731;0388 .

609 971-4000 Writer's Direct Dial Nurnber:

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July 20,1990 U.S.'. Nuclear Regulatory Commission

' -Attnt' Documer.t-Control-Desk washington,!D.C. -20555 M Dear Sir L' Subject Oyster Creek Nuclear Generating-Station y'

Docket No. 50-219 NUREO 0737 Item II.K.3.16

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The purpose of this' letter it to advise you of a change to the preventive:

. maintenance - program f or Electromatic Relief \'alves - (EMRVs) .

.c p-Ouricorrespondence' dated October 3,'1984-described'the Preventive Maintenance'

. Program for(the Dresser EMRVs which requires that.all five'(5) valves be, tested and refurbished each' refueling outage. . These valves were refurbished during ithe Cycle 11 and 12 refueling outage as committed.. This commitment-was based

on the: results- of the BWR Owners Group evaluation' of the subject NUREO 0737 11 tem'which addressed recurring malfunctions of safety / relief valves and-Dresser-

-Electromatic Relief.--valves'which at that. time were experiencing recurring malfunctions.t These malfunctions were' characterized by three categories: (1).

fallure offa valve to open properlyLon demand, (2)' spurious. opening of a. valve-

.with subsequent failure of the valve to properly reseat,"and (3):. proper opening

,Tof-a; valve;with, subsequent failure of-the valve to properly reseat. Spurious .-

. openings-and/or failure.of valves to properly reseat result in a loss of

' inventory from v.he vessel.

f 1; LTo address these concerns, Dresser Industries has: incorporated many-improvements.in the design of the EMRVs. Some of these include a new main and-ipilotIdisc design'to lmprove seat-tightness, welding of the main disc retainer.

to minimize the~offect ofcvibration on' valve internals, and other.designLand materialuupgrades. Most of these design upgrades ~have been incorporated in the-

original OPUN'EMRVs and all.have been~ incorporated in the' replacement valves 4;thatiare used as spares. Surveillance test results demonstrate these-Eimprovements have-been successfulfin ensuring valve operability.

f Based-on:the above developments and information, the prior GPUN program to Erebuild all five EMRVs each refueling outage is too coriservative and,-

therefore,:is being revised. Beginning in 13R, the rebuild schedule will be U gmodifiee. to require rebuilding (or installation of a rebuilt spare valve) two

or three EMRVs during the. refueling outage and rebuilding the remaining valves during the next refueling outage. lQ 900NOOO90 900720 DR ADOCK 0500

,. GPU Nuclear Corporation is a subsidiary of General Public Utilities Corporation

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1*\ M l :s Based on operating cycles of 24 months, all five EMRVs would be rebuilt every

- 48 months._ This proposed schedule has been discussed with engineering

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representatives _from Dresser Industries who agree that 48 months is an acceptable schedule- as long as the valves are cycled periodically. In~

- accordance with oyster Creek Technical Specifications, valve operability is

- demonstrated every; refueling outage.

should you have any' questions regarding the change to our preventive

_ maint enance program on the_ EMRVs, please call Brenda DeMerchant, oyster Creek-Licensing Engineer _'at 609-971-4642.

Very truly yours,

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. Fitzpatrick .Nrv Vice President and Director-oyster Creek EEF/BDeM/jc . . .

ces Mr.=: Thomas Martin, Administrator Region.1 U.S. Nuclear Regulatory Commission J475 Allendale.RoadL KingLof' Prussia, PAL _19406 Mr'.' Alexander Dromerick,: Project' Manager

U.S. Nuclear Regulatory Commission Mail Station Pl-137

. Washington, DC 20555 NRC Resident Inspector , ,

. Oyster Creek Nuclear Generating Station i

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