05000339/LER-1980-052-03, /03L-0:on 800823,w/unit at 4% Power,C Main Steam Trip Valve Would Not Fully Close Using Train a Close Pushbutton.Caused by Solenoid Operated Valve in Instrument Air Line to Trip Valve Stuck in Open Position

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/03L-0:on 800823,w/unit at 4% Power,C Main Steam Trip Valve Would Not Fully Close Using Train a Close Pushbutton.Caused by Solenoid Operated Valve in Instrument Air Line to Trip Valve Stuck in Open Position
ML19332A812
Person / Time
Site: North Anna 
Issue date: 09/12/1980
From: Cartwright W
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19332A809 List:
References
LER-80-052-03L-01, LER-80-52-3L-1, NUDOCS 8009180417
Download: ML19332A812 (3)
v • d • e


LER-1980-052, /03L-0:on 800823,w/unit at 4% Power,C Main Steam Trip Valve Would Not Fully Close Using Train a Close Pushbutton.Caused by Solenoid Operated Valve in Instrument Air Line to Trip Valve Stuck in Open Position
Event date:
Report date:
3391980052R03 - NRC Website
v • d • e

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

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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/V/A/N/A/S/2/ (2)

LO/0/-/0/0/0/0/0/-/0/0/ (3)

/4/1/1/1/1 (4)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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(8) /o/9/1/2/8/0/ (9)

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

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On August 23, 1980 with the Unit at 4% power, the "C" main steam trip valve

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would not fully close using the Train "A" close pushbutton contrary to T.S.

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3.7.1.5 and reportable persuant to T.S. 6.9.1.9.b.

Since the valve could be

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closed from the Train "B" close pushbutton, the health and safety of the public/

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were not not affected. The incident has no generic implication.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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/H/B/ (11) /E/ (12) /B/ (13) /V/A/L/V/E/X/ (14) LD/ (15)

LE/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

(17) REPORT NUMBER

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ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP.

COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURFR

/B/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) LY/ (23) /N/ (24) /A/ (25) /A/4/9/9/ (26 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The trip valve would not close completely because a solenoid operated valve in /

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the instrument air line to the trip valve stuck in the open position. The trip /

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valve was closed with the Train "B" close pushbutton. The solenoid operated

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valve was repaired and tested satisfactorily.

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FACILITY METHOD OF

/( } DISCOVERY DISCOVERY DESCRIPTION (32)

STATUS

% POWER OTHER STATUS

/A/ (31)

/ OPERATOR OBSERVATION /

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/B/ (28)

/0/0/4/ (29) /

NA ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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/Z[ (33)

/Z/ (34) /

NA

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NA

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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NA

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PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY TYPE

DESCRIPTION

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NA

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PUBLICITY DESCRIPTION (45) 800g 180 h[

NRC USE ONLY ISSUED

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

g Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 2 Docket No. 50-339 Report No. LER 80-52/03L-0

Description of Event

On August 23, 1980 with the, Unit at 4% power, the "C" sain steam trip valve would not fully close using the Train "A" close pushbutton.

The trip valve is required by T.S. 3.7.1.5 to close fully within 5 seconds. This is reportable persuant T.S. 6.9.1.9.b.

Probable Consequences of Occurance On a main steam isolation signal, Train "B" would have closed the trip valve, therefore the health and safety of the public were not affected.

Cause of Event

The cause of the event was originally thought to be a stuck open check valve in the instrument air line to the main steam trip valve.

The check valve was disassembled, cleaned and reassembled on August 23, 1980. The main steam trip valve was then tested satisfactorily and power operation continued. While the unit was at cold shutdown on September 3, 1980, the similar check valves in the instrument air lines to the main stesa trip valves were disassembled, cleaned and reassembled.

The main steam trip valves were tested for proper operation on Steptember 5, 1980 and again the "C" sain steam trip valve would not fully close.

using the Train "A" close pushbutton. The trip valve would not close completely because a solenoid operated valve in the instrument air line to the trip valve stuck in the mid position. When the Train "A" close pushbutton was depressed, both solenoid valves for "A" train began bleeding air from the trip valve to close the trip valve. However, because the solenoid operated valve was stuck in the mid-position more air was supplied to the trip valve and the trip valve would not close 4

completely. The solenoid operated valve stuck due to a piece of solder in the valve which prevented proper valve operation.

Immediate Corrective Action

The "C" saic steam trip valve was closed using the Train "B" close pushbutton. A check valve in the instrument air line to the main steam trip valve was cleaned and the trip valve tested satisfactorily. Similar check valves were cleaned. When the main steam trip valves were retested, "C" trip valve would not fully close from the "A" Train close pushbutton.

A solenoid operated valve 10 the instrument air line was taken apart, a piece 'of solder removed and the solenoid valve was reassmebled. All the sain steam trip valves were'then satisfactorily tested.

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Scheduled Corrective Action None scheduled.

_. _ _...- ~, - --,

r Attachment: Page 2 of 2 Action Taken to Prevent' Recurrence The main steam trip valves are tested for proper operation by a periodic test.

Generic Implication No generic implications at this time.

~

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