05000338/LER-1980-049-03, /03L-0:on 800524,in Mode 3,mechanical Chiller That Maintains Temp of Containment Bldg Failed.Caused by Air Voids in Chilled Water Sys Due to Leaking Valves & Previously Secured Recirculation Fans

/03L-0:on 800524,in Mode 3,mechanical Chiller That Maintains Temp of Containment Bldg Failed.Caused by Air Voids in Chilled Water Sys Due to Leaking Valves & Previously Secured Recirculation Fans

ML19318B692
Person / Time
Site:	North Anna
Issue date:	06/20/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19318B691	List: 05000338/LER-1980-049, Forwards LER 80-049/03L-0 05000338/LER-1980-049-03, /03L-0:on 800524,in Mode 3,mechanical Chiller That Maintains Temp of Containment Bldg Failed.Caused by Air Voids in Chilled Water Sys Due to Leaking Valves & Previously Secured Recirculation Fans
References
LER-80-049-03L, NUDOCS 8006270315
Download: ML19318B692 (2)

LER-1980-049, /03L-0:on 800524,in Mode 3,mechanical Chiller That Maintains Temp of Containment Bldg Failed.Caused by Air Voids in Chilled Water Sys Due to Leaking Valves & Previously Secured Recirculation Fans

Event date:
Report date:
3381980049R03 - NRC Website

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U.S. NUCLEAR REGULATORY COMMISSION t

- Q 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 May 24, 1980, with the unit in Mode 3, the mechanical chiller that maintains /

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temperature of the containment building failed and the average temperature of /

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the containment increased above 105 *F.

This is contrary to T.S. 3.6.1.5 and /

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reportable pursuant to T.S. 6.9.1.9.b.

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SYSTEM

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

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ACTION FUT M EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP.

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_TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MAhTFACTURER

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27) l/1/0/

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The mechanical chiller failed and before the steam chiller could be lined up to/

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operation, the containment building temperature increased above tech. spec.

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limits.

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FACILITY METHOD OF STATUS

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ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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LOSS OF OR DAMAGE TO FACILITY

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PUBLICITY

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

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

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 80-049/03L-0

Description of Event

On May 24, 1980, with the unit in Mode 3, the mechanical chiller that maintains temperature of the containment building failed and the average temperature of the containment increased above 105*F.

This is contrary to T.S. 3.6.1.5 and reportable pursuant to 6.9.1.9.b Probable Consequences of Occurrence The average bulk air temperature of the containment air fluctuates between a maximum temperature of 105 F and a minimum of 86 *F during normal operation.

The containment structure is designed to withstand an internal pressure of 45 psig and temperature of 280 F.

Since contain-ment average air temperature was restored below 105 F within eight hours of going above 105 *F, the health and safety of the general public were not affected by this event.

There are no generic implications associated with this occurrence.

Cause of Event

The mechanical chiller tripped due to high bearing temperature because chilled water flow was restricted to the chiller oil cooler.

During the time required to line up the steam chiller, the containment temperature rose above the tech. spec limit.

Immediate Corrective Action

Subsequent to the mechanical chiller trip, the steam chiller was placed in operation as quickly as possible to maintain the containment average air temperature within tech, spec. limits.

Scheduled Corrective Action No scheduled corrective action is required.

Actions Taken to Prevent Recurrence The cause of the low chilled water flow to the oil cooler was determined and the problem was corrected.

While switching containment Recire. fans with the mechanical chiller lined up to both containments, air voids in the chilled water system caused by leaking valves and previously secured Recire. fans air bound the chilled water system piping ar.d caused the low flow condition to the mechanical chiller oil cooler.

To prevent the condition from recarring, these valves are maintained closed and the recire. fans are rotated frequently.

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