05000339/LER-1983-016-03, /03L-0:on 830115 & 16,both Open & Closed Containment Isolation Valves TV-SI-200 & TV-CC-204C,train a Position Indication Lights Found Lit.Caused by Leaking Steam Generator Chemical Feed Line Vent Valve

/03L-0:on 830115 & 16,both Open & Closed Containment Isolation Valves TV-SI-200 & TV-CC-204C,train a Position Indication Lights Found Lit.Caused by Leaking Steam Generator Chemical Feed Line Vent Valve

ML20028G631
Person / Time
Site:	North Anna
Issue date:	02/09/1983
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20028G624	List: 05000339/LER-1983-016, Forwards LER 83-016/03L-0 05000339/LER-1983-016-03, /03L-0:on 830115 & 16,both Open & Closed Containment Isolation Valves TV-SI-200 & TV-CC-204C,train a Position Indication Lights Found Lit.Caused by Leaking Steam Generator Chemical Feed Line Vent Valve
References
LER-83-016-03L, LER-83-16-3L, NUDOCS 8302170158
Download: ML20028G631 (3)

LER-1983-016, /03L-0:on 830115 & 16,both Open & Closed Containment Isolation Valves TV-SI-200 & TV-CC-204C,train a Position Indication Lights Found Lit.Caused by Leaking Steam Generator Chemical Feed Line Vent Valve

Event date:
Report date:
3391983016R03 - NRC Website

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

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT 0/1/

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/0/2/0/9/8/3/ (9) 0 RC DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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/ On January 15, 1983, with Unit 2 in Mode 1, both the open and closed Containment /

/0/3/

/ Isolation Valve TV-SI-200 train A position indication lights were found lit. On /

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/ January 16, 1983, with Unit 2 in Mode 1, both the open and closed Containment

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/ Isolation Valve TV-CC-204C train A position indicating lights were found lit.

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/ Both events are reportable pursuant to T.S. 6.9.1.9.d.

Both valves remained

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/ operable. The public health and safety were not affected.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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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 ACTIOH ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ A leaking steam generator chemical feed line vent valve sprayed liquid on the

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/ containment isolation valves. The train A limit switches on both valves filled /

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/ with chemical feed water and shorted. The leak was diverted to a floor drain.

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/ The limit switches were dried out and proper operation verified. Permanent leak /

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/ repair is scheduled for the next outage.

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FACILITY METHOD OF STATUS

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/E/ (28)

/0/3/0/ (29)

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/A/ (31)

/ Operator Observation /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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EK302170158 830209 LOSS OF OR DAMAGE TO FACILITY (43) PDR ADOCK 05000339 TYPE

DESCRIPTION

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PUBLICITY ISSUED DESCRIPTION (45)

.NRC USE ONLY

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

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t Virginia Electric and Power Company North Anna Power Station, Unit No. 2 Attachment: Page l'of 2 Docket No. 50-339-Report No. LER 83-016/03L-0

Description of Event

On January 15, 1983, with Unit 2 in Mode 1 at 30 percent of Rated Thermal ~ Power, both the open and closed Containment Isolation. Valve TV-SI-200 Train A position indication lights were found lit.

On January 16, 1983, with Unit 2 in Mode 1 at 30 percent of Rated Thermal Power, both the open and closed Containment Isolation Valve TV-CC-204C train A position indication lights were found lit.

Both events are reportable

{;

pursuant t'o T.S. 6.9.1.9.d.

Probable Consequences of Occurrence 4

One set of open limit switch contacts for containment isolation valves are wired in parallel to.the open pushbutton contacts and in

('

series with the closed pushhutton contacts.

Shorting across both the train A and train B open limit switch contacts will'cause a containment isolation valve to open. Although a phase A or B isolation signal will interrupt the circuit and cause a containment isolation valve with i

shorted open limit switch contacts to close, when the initiating signal is reset, the K-relay will de-energize and the containment isolation valve will automatically reopen.

This is contrary to the operation described in UFSAR Section 7.3.1.3.5.2,

. which requires two operator actions to reopen a containment isolation valve once it has been shut by j

an ESF signal.

The failures of TV-SI-200 and TV-CC-204C limit switches occurred 3

only in train A circuits.

With the train B circuits operable,. valve f

control was unaffected and the valves would have closed from either a train A or B isolation signal and would have remained closed af ter ESF reset. A reduction in the degree of redundancy was the only consequence of the failed limit switches.

Both TV-SI-200 and TV-CC-204C remained operable throughout the event.

Check valves which provide redundant containment isolation for TV-SI-200 and TV-CC-204 remained operable throughout the event.

The public health and safety were not affected.

{

Cause of Event

An overhead steam generator chemical feed line vent - valve was leaking and sprayed liquid on the containment isolation valves.

The train A limit switches on both valves filled up internally with chemical feed water and shorted.

}

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Immediate Corrective Action

The chemical feed line leak was diverted using a plastic hose (tygon hosing) to s. floor drain. The limit switch housings were drained and dried out.

Valve indications returned to normal.

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4 Attachment: Page 2 of 2 Scheduled Corrective Action The chemical feed line leak has not been repaired for ALARA rea-sons. The leak will be repaired during the next outage. A preventative maintenance program to inspect limit switches and associated conduit for water tightness will be implemented.

Actions Taken to Prevent Recurrence The scheduled corrective actions should prevent recurrence.

Generic Implications The events discribed above do not have generic implications.

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