ML19320B113

LER 80-026/03L-0:on 800620,w/reactor in Mode 2 & as Part of 2-SU-31,channel F-497 Was Observed to Require Adjustment in Order to Lower Feedwater Flow Indication.Caused by Zero Shift in multiplier-divider Card of Feedwater Channel F-497

ML19320B113
Person / Time
Site:	North Anna
Issue date:	07/02/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19320B109	List: ML19320B108 ML19320B113
References
LER-80-026-03L-01, LER-80-26-3L-1, NUDOCS 8007090323
Download: ML19320B113 (2)

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,x U.S. NUCLEAR REGULATORY COMMISSION l

x / LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/ /V/A/N/A/S/2/ (2) /0/0/-/0/0/0/0/0/-/0/0/ (3) /4/1/1/1/1 (4) / / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/0/1/ REP

/L/ (6) /0/5/0/0/0/3/3/9/ (7) /0/6/2/0/8/0/ /0/7/0/2/8/0 (9)

OU (8)

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

/0/2/ / With the reactor in Mode 2 and as part of the 2-SU-31 (Nuclear amd Temperature /

/0/3/ / and Thermal Power Measurement), channel F-497 was observed to require adjust- /

/0/4/ / ment in order to zero the feedwater flow indication. Testing of the channel /

/0/5/ / revealed the square root extractor (multiplier-divider) indicated approximately/

/0/6/ / 6.5% high at zero flow, the channel bistables were placed in trip during the /

/0/7/ / test, the redundant channel remained ooerable and the health and safety of the /

/0/8/ / general public was not affected. Event reportable pursuant to T.S. 6.9.1.9.a. /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /I/A/ (11) /E/ (12) /E/ (13) /I/N/S/T/R/U/ (14) [Y/ (15) [Z/ (16)

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

(17) REPORT NUMBER /8/0/ /-/ /0/2/6/ /\/ /0/3/ [L[ /-/ [0/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/E/ (18) /2/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) [Y/ (23) /N/ (24) /N/ (25) /H/0/1/5/ (26 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / This event was caused by a zero shift in the multiplier-divider card of feed- /

/1/1/ / water flow channel F-497. This channel was out of service for approximately /

/1/2/ / 3 1/2 hours. The multiplier-divider was readjusted and the channel was /

/1/3/ / satisfactorily returned to service. /

/1/4/ / /

FACILITY METHOD OF STATUS  % POWER OTHER STATUS DISCOVERY DESCRIPTION (32)

/1/5/ /B/ (28) /0/0/0/ (29) [_ NA / 5- ) DISCOVERY

/C/ (31) / Instru. Technician /

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36)

/1/6/ /Z/ (33) /Z/ (34) / NA / / NA /

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) LZZ (38) / NA /

l PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) / NA /

LOSS TYPE OF OR DAMAGE TO FACILITY ('3)

DESCRIPTION

/1/9/ /Z/ (42) / NA /

PUBLICITY ISSUED DESCRIPTIO" (45) NRC USE ONLY

/2/0/ /N/ (44) / NA /////////////

V. R. CARMGHT PHONE (703) 894-5151 8 007 0 90 M 3NAME OF PREPARER

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i Virginiu Electric and Power Company North Anna Power Station, Unit #1

Attachment:

Page 1 of I Docket No. 50-339 Report No. LER 80'020/03L-0 Description of Event Technical specification 3.3.1.1 (Table 3.3-1 item 15) requires Main Feedwater Flow channels to be operable in Mode 2. Additionally, 2-SU-31 (Nuclear and Temperature and Thermal Power Measurements) requires zero feedwater flow indication as preparation for initial startup above Mode

2. Feedwater flow channel F-497 was observed as part of 2-SU-31 and subsequent testing of the channel revealed the multiplier-divider card which calculates the square root of feedwater AP developed a zero flow indication approximately 6.5% too high.

Probable Consequences of Occurrence The consequences of this event were limited since the feedwater flow was tested by procedure with the channel in trip and the redundant feedwater flow channel was in service. Additionally the reactor was in initial Mode 2 startup testing with essentially no decay heat present.

The need for loss of feedwater flow protection, of which F-497 is an input, has more importance once the reactor has operated at power and generated decay heat. The healun and safety of the general public was not affected by the occurrence.

Cause of Event The event was caused by a zero shift of approximately 6.5% in the multiplier-divider output. This resulted in too high a feed flow indi-cation at minimum flow. The zero shift was attributed to electronic drift and the high sensitivity of the minimum output adjustments. This drift is normally attributable to this component and is not believed to be generic.

Immediate Corrective Action The multiplier-divider occurrence is related to a previously sub-mitted LER/80-024/01T-0 which reported five feedwater transmitters isolated. Tn LER/80-024/01T-0, corrective action returned all trans-mitters to service. -Channel F-497 was returned to service with these transmitters, but required additional testing because of the multiplier-divider zero shift.

Corrective action was to place F-497 in trip, perform readjustment i of the multiplier-divider, while the redundant channel remained operable.

Scheduled Corrective Action l

No scheduled corrective action is required.

l l Actions Taken to Prevent Recurrence l No further action is required.

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