05000339/LER-1980-055-03, /03L-0:on 800905,results of Periodic Valve Inservice Test Revealed Excessive Leakage Past 2-SI-70. Caused by Corroded Seating Plug.Valve Replaced & Tested Satisfactorily

/03L-0:on 800905,results of Periodic Valve Inservice Test Revealed Excessive Leakage Past 2-SI-70. Caused by Corroded Seating Plug.Valve Replaced & Tested Satisfactorily

ML19338F184
Person / Time
Site:	North Anna
Issue date:	10/01/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19338F183	List: 05000339/LER-1980-055, Forwards LER 80-055/03L-0 05000339/LER-1980-055-03, /03L-0:on 800905,results of Periodic Valve Inservice Test Revealed Excessive Leakage Past 2-SI-70. Caused by Corroded Seating Plug.Valve Replaced & Tested Satisfactorily
References
LER-80-055-03L-01, LER-80-55-3L-1, NUDOCS 8010070607
Download: ML19338F184 (3)

LER-1980-055, /03L-0:on 800905,results of Periodic Valve Inservice Test Revealed Excessive Leakage Past 2-SI-70. Caused by Corroded Seating Plug.Valve Replaced & Tested Satisfactorily

Event date:
Report date:
3391980055R03 - NRC Website

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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / /j (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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E DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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On Septe:nber 5,1980 the results of a periodic valve inservice test showed

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excessive leakage past 2-SI-70 (a check valve in the Boron Injection tank

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recirculation line). This valve was possibly inoperable during previous plant /

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operation and therefore contrary to T.S. 3.5.2.c.

Since the redundant valve

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in this line-TV-2884C was operable, and the unit was in mode 5 at the time of /

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discovery, the health and safety of the public sere not affected.

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SYSTEM

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VALVE CODE CODE SUBCODE COMPONENT COD 5.

SUBCODE SUBCODE

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/Of ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT MZTHOD HOURS SUBMITTED EORM SUB. SUPPLIER MANUFACTURER

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The check valve concerned was a 2" Rockwell Edwards positive action forged

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univalve. The valve was cut out, examined and the seating plug was found to

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be corroded and apart from the seating spring. This apparently caused the

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spring to s' lip off the plug causing the valve to jam in the open position.

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The valve was replaced and tested satisfactorily.

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FACILITY METHOD OF STATUS

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Surveillance

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LOSS OF OR DAMAGE TO FACILITY G3)

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PUBLICITY ISSUED DESCRIPTION (45)

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/ffffff/fffff NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151

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Virginia Electric and Power Company North Anna Power Station, Unit #2 Attachment: Page 1 of 2 Docket No. 50-339 Report No. LER 80-055-03L-0

Description of Event

On September 5,1980 with Unit 2 in cold shutdown the results of a periodic valve inservice test showed leakage past 2-SI-70 (a check valve in the Boric Acid Tank to Boron Injection Tank Recirculation Line) to be i

in excess of 1200 CC/ min - the maximum acceptable. The valve was later found to be jammed in the open position. This condition is thought to have existed while operating in Modes 1 - 3.

This event is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence The consequences of this event were limited in that the redundant valve (TV-2384C) in the above mentioned recirculation line receives a close signal en a ESF actuation which would have acted to prevent charging to the Boric Acid Tanks thereby preventing any diverting of safety injection flow away from the injection path. As a result, the health and safety of the public were not affected by this event.

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Cause of Event

The concerned valve was a 2" positive action Rockwell Edwards forged univalve. The valve was cut out and examined. However, the examinstion could at first only include a visual inspection through the throat of the valve because the valve cap was damaged on removal of the valve from the system. The initial inspection showed that the seating plug which rides on the seat when closed, and on a spring when open, seemed to be corroded and apart from the spring. The spring apparently slipped off the damaged plug and caused the valve to stick in the open position. Subsequently, the valve was cut open and the seating plug removed. Upon comparing the valve internals to replacement parts in inventory, it was discovered that the wrong internals had been used in the failed valve.

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Immediate Corrective Action

Because the plant was in mode 5 - cold shutdown - and the protection afforded by this velve was not required - the immediate corrective action was to place the Boron Injection System in an inoperable status thus precluding entrance into a higher modo until the valve was repaired.

The valve was cut out and replaced with an identical valve. The socket welds on the new valves were liquid penetrateitested and found acceptable.

The entire assembly was then hydrostatical,17 tested and leak checked in accordance with approved procedures. All-testing proved satisfactory and the valve and the associated flew path-were placed back in an operable status.

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Attachment:

Page 2 of 2 Scheduled Corrective Action The LCO was met, the system repaired, and no further corrective action is needed.

Action Taken to Prevent Recurrence No additionar. action is presently planned to prevent recurrance other than to perform all required valve in service periodic surveillance tests as required.

Generic Implications Based on operating experience with similar valves, this failure appears to be an isolated event.

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