05000366/LER-1981-056-03, /03L-0:on 810716,torus Water Temp Exceeded 95 F. Caused by Elevated Cooling Water Temp Due to Hot Weather Conditions.Torus Cooling Procedures Performed in Early Morning

/03L-0:on 810716,torus Water Temp Exceeded 95 F. Caused by Elevated Cooling Water Temp Due to Hot Weather Conditions.Torus Cooling Procedures Performed in Early Morning

ML20010D181
Person / Time
Site:	Hatch
Issue date:	08/11/1981
From:	Coggin C GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010D177	List: 05000366/LER-1981-056, Forwards LER 81-056/03L-0 05000366/LER-1981-056-03, /03L-0:on 810716,torus Water Temp Exceeded 95 F. Caused by Elevated Cooling Water Temp Due to Hot Weather Conditions.Torus Cooling Procedures Performed in Early Morning
References
LER-81-056-03L-01, LER-81-56-3L-1, NUDOCS 8108240082
Download: ML20010D181 (2)

LER-1981-056, /03L-0:on 810716,torus Water Temp Exceeded 95 F. Caused by Elevated Cooling Water Temp Due to Hot Weather Conditions.Torus Cooling Procedures Performed in Early Morning

Event date:
Report date:
3661981056R03 - NRC Website

text

NRC F ORM 36G U. S. NUCLE AR REGULATORY COMMISSION (7 7{}

LICENSEE EVENT REPORT

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8 60 61 DOCK ET NUMBER 6h b9 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h i0i2, puring normal operation, torus water temperature exceeded 95 F.

No sig-1 nificant occurrence took place as a result'of this event.

This type I

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g pvent is applicable to both units and was last reported by report no.

I io,,jp0-321/1981-078.

This event temporarily degraded the quenching ability 1

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This event posed no threat to public health or safe-l g o ;, j i y.

No redundant system exists for the torus.

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Corrective actions which have been taken are describedI lin the attached narrative.

No further corrective actions will be taken.]

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LER #:

50-366/1981-056 Licensee:

Georgia Power Company Facility Name:

Edwin I. Hatch Docket #:

50-366

Narrative

Report for LER 50-366/1981-056 During normal unit operation it was noted that torus water Lemperature had reached 940F, and torus air temperature had reached 1050F.

At this point torus water cooling procedures were initiated.

This action causes torus water to be routed through residual heat removal system heat exchangers and then back to the torus.

The result of this action was a temporary increase in torus water temperature to a maximum of 980F.

Continued cooling operations then brought the water temperat-ure back down to below the Tech Specs limit of 950F.

The consequence of this occurrence was a temporary degradation of the steam quenching capability of the torus water.

The magni-tude of this degradation was small, and this occurrence did not significantly reduce the safety factors associated with containment integrity.

No redundant system exists for the torus.

This event posed no threat to public health or safe-ty.

This type event is applicable to both units and was last reported by LER #50-321/1981-078.

The cause of this event is mainly attributable to the elevated cooling water temperatures common to this time of year.

The temperature increase that occurred upon initiation of torus water cooling operations was a result of heat transfer from torus air to torus water which occurred due to return water spraying; normally, removal of heat from the torus water by the RHR heat exchangers would account for this effect with a final result of water temperature reduction.

However, high cooling water temperature reduced the effectiveness of this function.

In order to minimize the frequency of this type of occurrence torus cooling procedures are performed in the early morning when cooling water temperatures are lowest.

Also cooled water can be returned directly into the torus water uithout spraying it thru the torus air.

Which return path to use is determined by the shift foreman prior to commencement of cooling procedures.

This ensures that every attempt is made to maintain the torus water at the lowest possible temperature without ever exceeding the high temperature limit.

Since this is a seasonal effect no further procedure changes or design modifications will alleviate the problem.

Therefore, no further corrective actions will be initiated.

No further reporting is required.