05000339/LER-1981-006-03, /03L-0:on 810107,w/unit at 1% Power,Average RCS Temp Less than 541 F on Two Occasions.Caused by Overfeeding Steam Generators Due to Feedwater Control Problems.Condenser Steam Dumps Closed & Reactor Temp Increased

/03L-0:on 810107,w/unit at 1% Power,Average RCS Temp Less than 541 F on Two Occasions.Caused by Overfeeding Steam Generators Due to Feedwater Control Problems.Condenser Steam Dumps Closed & Reactor Temp Increased

ML20003B146
Person / Time
Site:	North Anna
Issue date:	02/04/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20003B144	List: 05000339/LER-1981-006-03, /03L-0:on 810107,w/unit at 1% Power,Average RCS Temp Less than 541 F on Two Occasions.Caused by Overfeeding Steam Generators Due to Feedwater Control Problems.Condenser Steam Dumps Closed & Reactor Temp Increased
References
LER-81-006-03L-01, LER-81-6-3L-1, NUDOCS 8102100439
Download: ML20003B146 (2)

LER-1981-006, /03L-0:on 810107,w/unit at 1% Power,Average RCS Temp Less than 541 F on Two Occasions.Caused by Overfeeding Steam Generators Due to Feedwater Control Problems.Condenser Steam Dumps Closed & Reactor Temp Increased

Event date:
Report date:
3391981006R03 - NRC Website

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

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

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/ On January 7,1981 with Unit at 1% power, the average reactor coolant system

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/ temperature was less than 541*F with the reactor critical on two occasions.

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/ However, on each occasion, the temperature was restored to within its limits

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/ (2 541*F) within 15 minutes as required by Technical Specifications. Conse-

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/ quently, the health and safety of the public were tot affected.

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SYSTEM

CAUSE

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VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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

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ACTION FUTURE EFFECT SHUTDOWN ATTACEMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER [X[ (18) [Zf (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) g/ (23) [N[ (24) [Z[ (25) /Z/9/9/9/(26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ Each event was caused by overfeeding of the steam generators, due to feedwater /

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/ control problems, and decreasing reactor coolant temperatures due to xenon

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/_ buildup. Corrective action was to secure feeding the steam generators, to close/

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/ the condenser steam dumps and to increase reactor temperature by dilution and

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/ pulling the control rods.

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FACILITY METHOD OF STATUS

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Operator Observation

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

02 1 o o't'$

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Virginia' Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docker No. 50-339 1

Report No. LER 81-006/03L-0

Description of Event

On January 7,1981 with Unit II at 1* power, the average reactor coolant system (RCS) temperature was less than 541*F with the reactor critical on two occasions. The total time that this situation existed was 10 minutes in duration.

In each occurence, the average RCS tempera-ture was brought within its noraal parameters within 15 minutes as required by Technical Specification. This event is contrary to T.S.

3.1.1.5, and reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence 4

Since RCS average temperature was brought within specifications as required by the 3ction requirements of the limiting conditions for operation, the health and safety of the public were not affected.

Cause of Event

The reactor was critical with average reactor coolant temperature

- I below 541*F due to overfeeding of the steam generators, and decreasing reactor temperature due to xenon build-up.

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Immediate Corrective Action

l The immediate corrective action was to secure feeding the steam ~

l generators; to close the steam dump valves; and to increase reactor l

coolant temperature by dilution :La pulling control rods.

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Scheduled Corrective Action There is no corrective action.

l Actions Taken to Prevent Reccurrence The operators were cautioned'about overfeeding the steam generators

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during a reactor startup.

Generic Implications 1

There are no generic implications to this event.

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