05000338/LER-1981-051-03, /03L-0:on 810703-08,containment Average Air Temp Exceeded Tech Specs.Caused by Temporary Loss of Cooling Medium.Temp Reduced by Placing Steam Chiller in Svc

/03L-0:on 810703-08,containment Average Air Temp Exceeded Tech Specs.Caused by Temporary Loss of Cooling Medium.Temp Reduced by Placing Steam Chiller in Svc

ML20009H550
Person / Time
Site:	North Anna
Issue date:	07/30/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009H543	List: 05000338/LER-1981-051, Forwards LER 81-051/03L-0 05000338/LER-1981-051-03, /03L-0:on 810703-08,containment Average Air Temp Exceeded Tech Specs.Caused by Temporary Loss of Cooling Medium.Temp Reduced by Placing Steam Chiller in Svc
References
LER-81-051-03L-01, LER-81-51-3L-1, NUDOCS 8108100232
Download: ML20009H550 (2)

LER-1981-051, /03L-0:on 810703-08,containment Average Air Temp Exceeded Tech Specs.Caused by Temporary Loss of Cooling Medium.Temp Reduced by Placing Steam Chiller in Svc

Event date:
Report date:
3381981051R03 - 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

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

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/ During Mode 1 operation on July 3 and 8, 1981, the containment average air tem-

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/ perature exceeded the u,per Technicial Specification limit of 105 F.

Since the /

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/ containment bulk air temperature was restored to within the limit of T.S. 3.6.1.5/

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/ within the allowed 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> on each occasion, the public health and safety were

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/ not affected. The events are reportable pursuant to T.S. 6.9.1.9.b.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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/S/B/ (11) /X/ (12) [Z/ (13) /Z/Z/Z/Z/Z/Z/ (14) /Z/ (15)

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

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ Both high cc,ntainment temperatures resulted from a temporary loss of cooling

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/ medium. The first high temperature occurred when the mechanical chiller tripped /

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/ while attempting to parallel with the steam chiller and the second event resulted/

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/ from degraded service water flow during a test. Temperature was reduced by plac-/

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/ ing the steam chiller in service and by returning service water flow to normal.

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISC M RY K R M W (32)

/ (30) DIS N RY

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NA

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Operator Observat A,_/

ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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PERSONNEL EXPOSURES hW!BER TYPE DESCRIPTION (39)

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NA

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PERSONNEL INJURIES hW1BER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY G3)

TYPE

DESCRIPTION

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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ggelggg!2gggggg 3F PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 S

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Virginia Electric and Power Company North Anna Power Station, Unit #1

Attachment:

Page 1 of 1 Docket No. 50-333 Report No. LER 81-051/03L-0

Description of Event

On July 3 and 8, 1981, during Mode 1 operation, the containment average air temperature exceeded the upper Technicial Specification limit of 105 F.

These events are reportable pursuant to 't.S.

6.9.1.9.b.

Probable Consequences of Occurrence Since on both occasions the containment bulk air temperature was restored to within the limit of T.S. 3.6.1.5 within the allowed 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, the health and safety of the general public were not affected.

Cause of Event

The unit is presently operating with a containment air temperature close to the upper limit and thus any change in cooling water lineup or flow can have enough of an effect to cause the temperature to increase above the 105 F limit.

Both high containment average air temperatures resulted from the temporary degrading of an associated cooling medium. The high containment air temperature on July 3 was caused by a temporary loss of chilled water flow to the containment recirculation air cooling coils when the mechanical chiller unit tripped while attempting to parallel with the steam chiller. The high temperattree on July 8 resulted from degraded service water flow to the component cooling heat exchangers during periodic testing of a service water pump.

Immediate Corrective Action

Containment air temperature was reduced to below the 105 F limit by placing the steam chiller in service for the first occurrence and returning service water flow to normal for the second.

Scheduled Corrective Action The high containment heat load which appears to exist is presently being investigated. The performance of each contain.^ent recirculation air heat exchanger is being evaluated to determine if any cooling coils have degraded.

Plans also include checking all ring duct exhaust dampers open and vent seals closed during the next Mode 3 outage and inspecting insulation on various components such as the reactor head and steam generator supports for heat losses during the next refueling.

Actions Taken to Prevent Recurrence No further actions are required at this time.

Generic Implications There are no generic implications associated with this event.