05000338/LER-1981-025-03, /03L-0:on 810428-0505,containment Air Temp Exceeded 105 F.Caused by Steam Chiller Malfunction & Out of Svc Mechanical Chiller.Temp Reduced by Switching Bearing Cooling from Cooling Tower to Circulating Water Sys Tunnel

/03L-0:on 810428-0505,containment Air Temp Exceeded 105 F.Caused by Steam Chiller Malfunction & Out of Svc Mechanical Chiller.Temp Reduced by Switching Bearing Cooling from Cooling Tower to Circulating Water Sys Tunnel

ML19350D967
Person / Time
Site:	North Anna
Issue date:	05/22/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19350D942	List: 05000338/LER-1981-025, Forwards LER 81-025/03L-0 05000338/LER-1981-025-03, /03L-0:on 810428-0505,containment Air Temp Exceeded 105 F.Caused by Steam Chiller Malfunction & Out of Svc Mechanical Chiller.Temp Reduced by Switching Bearing Cooling from Cooling Tower to Circulating Water Sys Tunnel
References
LER-81-025-03L-01, LER-81-25-3L-1, NUDOCS 8105270427
Download: ML19350D967 (2)

LER-1981-025, /03L-0:on 810428-0505,containment Air Temp Exceeded 105 F.Caused by Steam Chiller Malfunction & Out of Svc Mechanical Chiller.Temp Reduced by Switching Bearing Cooling from Cooling Tower to Circulating Water Sys Tunnel

Event date:
Report date:
3381981025R03 - NRC Website

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

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONS?.QUENCES (10)

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During full power operetion on April 28, 29, 30 and May 5, 1981, containment

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average air temperature exceeded 105'F.

Since the containment average air

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temperature was restored to within the limit of T.S. 3.6.1.5 within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> on /

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each occurrence, the health and safety of the general public were not affected./

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This is reportable pursuant to T.S. 6.9.1.9.b.

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SYSTEM

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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High containment average temperature was caused by an improperly operating

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steam chiller and a mechanical chil.ler which was out of service. Containment /

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temperature was reduced by switching bearQ g cooling from the cooling tower to /

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the circulating water system tunnel to supply cooler water to the steam chiller /

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resulting in improved chiller condenser performance.

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NRC USE ONLY

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NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 820527090 1

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Virginia Electric and Power Company North Anna Power Station, Unit #1 Attachment: Page 1 of I Docket No. 50-338 Report No. LER 81-025/03L-0

Description of Event

During full power operation on April 28, 29, 30 and May 5, 1981, containment average air temperature exceeded 105'F.

Probable Consequences of Occurrence Since containment average air temperature was restored to within the

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limit of T.S. 3.6.1.5 within 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

High containment average temperature was caused by an improperly operating steam chiller and a mechanical chiller which was out of service.

Immediate Corrective Action

Containment air temperature was reduced by switching bearing cooling water from the cooling tower to the circulating water system tunnel to supply cooler water to the steam chiller condenser.

Scheduled Corrective Action There is no corrective action at this time.

l Actions Taken to Prevent Recurrence The 1000 ton mechanical chiller has been restored to operable status.

The steam chiller which is the normal standby system was removed from service to perfom correcti-2 maintenance.

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

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