05000339/LER-1980-049-03, /03L-0:on 800822,operating in Mode 2 at 3% Power, Loops a & C Channel Tour Steam/Flow Bistables Were Tripped to Allow Mod to Condensate Pots.Upon Return to Svc,A Failed High.Caused by Instrument Drift & Improper Valve Lineup

/03L-0:on 800822,operating in Mode 2 at 3% Power, Loops a & C Channel Tour Steam/Flow Bistables Were Tripped to Allow Mod to Condensate Pots.Upon Return to Svc,A Failed High.Caused by Instrument Drift & Improper Valve Lineup

ML19338D316
Person / Time
Site:	North Anna
Issue date:	09/16/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19338D274	List: 05000339/LER-1980-049, Forwards LER 80-049/03L-0 05000339/LER-1980-049-03, /03L-0:on 800822,operating in Mode 2 at 3% Power, Loops a & C Channel Tour Steam/Flow Bistables Were Tripped to Allow Mod to Condensate Pots.Upon Return to Svc,A Failed High.Caused by Instrument Drift & Improper Valve Lineup
References
LER-80-049-03L-02, LER-80-49-3L-2, NUDOCS 8009220319
Download: ML19338D316 (2)

LER-1980-049, /03L-0:on 800822,operating in Mode 2 at 3% Power, Loops a & C Channel Tour Steam/Flow Bistables Were Tripped to Allow Mod to Condensate Pots.Upon Return to Svc,A Failed High.Caused by Instrument Drift & Improper Valve Lineup

Event date:
Report date:
3391980049R03 - NRC Website

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U.S. NUCLEAR REGULATORY *0MMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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

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On August 22, 1980, while operating in Mode 2 at 3% power, the channel IV steam /

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flow bistables for loops A and C were placed in the tripped condition to allow /

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modifiration to the associated condensate pots. After being returned to ser- /

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vice, the loop A channel failed high and was again placed in the tripped mode. /

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Also, that evening due to erroneous indication, the transmitter for the loop C /

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steam flow channel was inspected and found to be still isolated. The public

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health and safety were not affected by these events.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE CCMPONENT CODE SUBCODE SUBCODE

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ACTION FUTURE EFFECT SHUIDOWN ATTACIDfENT NPRD-4 PRIME COMP.

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The bistables were tripped to allow holes to be drilled through the caps above /

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the condensate pot vent valves in an attempt to prevent water from accumulating /

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in the pressure sensing lines. The high loop A steam flow indication was

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caused by instrumeqt drift which was corrected by recalibration and the im-

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proper loop C transmitter valve lineup vias the result of personnel error.

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FACILITY METHOD OF STATUS

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/ Operator Observation /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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LOSS OF OR DAMA".2 TO FACILITY (43)

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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 NAWa

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Virginia Electric and Power. Company

- North Anna Power Station,, Unit 2 Attachment: Page 1 of 1 Docker No. 50-339 Report No..LER 80-049/03L-0

Description of Event

~

{:

.On' August 22,.1980, while operating in Mode 2 at 3% power, the channel.IV steam flow bistables for A and-C loops (F-2475 and F-2495):

l were placed in the tripped: condition to accomplish a modification to the.

l transmitter. condensing pots., After being returned to service, the' loop A steam flow channel failed.high and was again placed in the tripped.

i a

- mode. Also, due to erroneous indication', the transmitter for the loop C steam flow ~ channel was inspected and found to be.still isolated. These l

events are reportable pursuant to T.S. 6.9.1.9.b and T.S. 6.9.1.9.c.

Probable Consequences of Occurrence i

l' The cons'equences of these events were limited because the steam.

flow channels were placed in the tripped mode as specified by T.S.

l 3.3.1.1 and 3.3.2.1 and redundant instrumentation was available. As a result, the health and safety'of the general public were not affected.

Cause of Event

The: steam flow bistables were placed in the tripped condition to allow holes to be drilled through the caps above the vent valve on the condensate pots in'an attempt to prevent steam from condensing in the 1 pressure sensing lines.

The high loop A steam flow indication later that day was caused by instrument drift ~and the improper valve lineup for the loop C transmitter was the result of. personnel error.

Immediate Corrective Action

l '

the desired modification performed.

The: loop A and C steam flow bistables (channel IV) were tripped and

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When the. loop.A steam flow' channel failed high, the bistable was

~ placed in the tripped condition within one hour as specified by T.S.

3.3.1.1 and 3.3.2.1 and the channel was satisfactorily recalibrated.

j Upon-discovering the loop C steam flow transmitter isolated, the-transmitter root valves were immediately reopened and proper indication

- was verified.

I Scheduled Corrective Action

~No scheduled. corrective action is required.

Actions Taken'to Prevent Reccurrence

. To eliminate the condensation problem in the pressure sensing line,

- all twelve steam flow transmitter condensate pots.have been relocated closer to their respective venturi.' Also, personnel were reinstructed-fon'the importance.of proper valve lineup.

! Generic Implicationsi t

There.are no? generic implications.

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