ML19323H687

Revised LER 80-001/01T-1:on 800105,while Performing Electromatic Relief Valve Operability Test,Valve Failed to Open.Caused by Improper Staking of Grub Screw During Assembly.Retainer Ring Replaced

ML19323H687
Person / Time
Site:	Oyster Creek
Issue date:	06/05/1980
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19323H683	List: ML19323H682 ML19323H687
References
LER-80-001-01T, LER-80-1-1T, NUDOCS 8006160055
Download: ML19323H687 (4)

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I & 60 61 OCO<1TNUMBER 68 69 EVEN" DESCRIPTION AND PRCB ABLE CC.'!3ECUENCES h to ;0 j l On January 5, 1980, while performing the electromatic relief valve oper- l ability test, the 'O' EMRV failed to open. Three attempts were made to l

o,0, j 10 l a i ! open the 'O' EMRV and each time there was no audible indication of steam l i n ,3 ; ; -flow detected and there was not a similar increase in the downcomer line l iO,,, , temperature as noted in the other EMRV tests. T.S.3.4.3.2 was violat.ed.  ;

j037, ; An investigation revealed that the retaining ring wa backed of f a few l turns. The other four EMRV's were inspected. (See Attachment) l

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41 iY 42 J@ lN 43 l@ l4A0 l 2 I h i 547IQ CAUSE OESCAieTION ANO CC A AECTIVE ACTIONS h l ia4 l The 'O' EMRV rine was backed off a0 cut six threads and the grub l lt it j l screw was missing. It accears the cause was imorocer staking of the l

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.,3; l sheared off. The grub screw f rom ' E' EMRV was missing. Action taken l gii4 ; ; and future corrective actions are. described in the attachment.  ;

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Jersey Central Power & Ught Company J AFA .' H vac.scn Asenue at Pure.rcowi scae Morns:cwn New Jersey 07360 201 539-6111 OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/80/1/1T-1 Report Date Update Report - June 5, 1980 Previous Report Date - January 21, 1980 Date of Occurrence January 5, 1980 identification of Occurrence Violation of the Technical Specifications, paragraph 3.4.8.2, when EMRV 'O' did not open when tested during shutdown.

This event is considered to be a reportable occurrence as defined in the Techni-cal Specifications, paragraph 6.9.2.A.2.

Conditions Prior to Occurrence The plant was being shutdown for refueling and maintenance.

The major parameters at the time of occurrence were:

Power: Reactor, 280 MWt Generator, O MWe Flow: Feedwater, . 8 x 106 //hr, Recirculation, 12.6 x 10* gpm Stack Gas: 2.67 x 10" uCi/sec Descriotion of Occurrence On Saturday, January 5, 1980 at approximately 3:00 AM, while performing the Electromatic Relief Valve Operability Test, the 'O' EMRV failed to open. There were three attempts to open the 'O' EMRV and each time there was no audible indication of steam flow detected, and there was not a similar increase in the downcomer line temperature as noted in the other EMRV tests. Upon further investigation there was evidence that the retaining ring was backed off a few -

turns. The other EMRV's were inspected because there is a potential for this 1 type failure. Upon removal of 'C' EMRV for examination of the retainer and its grub screw for proper installation and staking it was noticed that one side Jemen Cectral Power & Lp,nt Com:any :s a Memcer of tre General Puttic Utnit:es Sys:er-

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• Reportable Occurrence No. 50-219/80/1/1T-1 Page 2 June 5, 1980 Previous Report Date: January 21, 1980 of the retainer was 3/8" higher than the other side with respect to the valve body. The retainer could not be disassembled by conventional methods, and had to be machined out. After removal, the examination of the threaded areas 1 revealed that the threads were sheared o.n the retainer, but were good in the valve body. -

Accarent Cause of Occurrence The cause of this event is attributed to component failure and also to improper 1 procedure.

The 'D' EMRV retainer ring was backed off about six threads and the grub screw, which keeps the retainer ring in place, was missing. It appears the cause was 1 improper staking of the grub screw during previous assembly.

The 'C' EMRV retainer ring threads were sheared off. I1 Analysis of Occurrence The relief valves of the automatic depressurl:ation system enables the core spray system to provide protection against the small break in the event the feedwater system is not active. Since the 'O' EMRV was inoperable, the A.D.S.

was considered to be operable in a degraded mode. The loss of one EMRV has been addressed in the loss of cooling accident analysis.

Also, the relief valves are provided to remove sufficienc energy from the pri-mary system to prevent the safety valves from lifting during a transient. The ilmiting pressure transient is a turbine trip from rated . design power with a failure of the bypass to function. The five relief valves are required to operate to prevent reaching the lowest setpoint of the primary system safety valves. With four relief valves operable and the core thermal power above 1740 MWe, there was no assurance that the safety valves would not lift.

Corrective Action The other four EMRV's were removed and inspected for the same problem. The in-spection revealed that staking of the grub screw was either inadequate or not done. The grub screw from 'E' EMRV was missing and the retainer ring from 'C' EMRV was improperly positioned.

The 'C' EMRV retainer ring had to be replaced. 'The retaining ring will be tightened from 250 ft-lb. to 350 ft-16. The disc guide will be checked to be properly seated before tightening retainer. 1 The Maintenance Procedure (702.1.007) has been revised to describe the details -

to properly install the retainer ring and to stake the grub screw. The vendor recommended to install ~2 grub screws 180* apart. The grub screw is a positive method of securing the retainer ring and staking of the grub screws, when done p roperl y, is a positive method of securing the grub screw. The revised proce-dure also provides for a QA inspection of the staking.

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Reportable Occurrence No. 50-219/80/1/1T-1 Page 3

' June 5, 1980 Previous Report Date: January 21, 1980

'C' and 'C' ENRV's were rebuilt with the new grub screw arrangement and 'A', 1

'B' and 'E' grub screws will be changed when these valves are inspected.

Failure Data NR1080 Size: 6x3 Mfg.: Dresser industries l

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