ML19261B338

LER 79-008/03L-0 on 790121:reactor Max Cooling Rate Exceeded Due to Injection of Condensate Feedwater Into Reactor Vessel During Slowdown.Caused by Pressure Decreasing Below Condensate Booster Pump Discharge Pressure

ML19261B338
Person / Time
Site:	Hatch
Issue date:	02/07/1979
From:	Baxley S GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19261B335	List: ML19261B334 ML19261B338
References
LER-79-008-03L-01, LER-79-8-3L-1, NUDOCS 7902150343
Download: ML19261B338 (2)

Text

LICENSEE EVENT REPORT '

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EVENT DESCHIPTION AND pro 9 ACLE CONSECUENCES h

) 2 l Reactor maximum cooldown rate of 100 degrees F per hour was exceeded on Jan 21, 1979 i  ;

3 3 ldue to injection of condensate feedwater into reactor vessel during cooldown. The  ;  !

314ll moderator temperature was being reduced to bring recirc loop temperatures within 50 l  ;

a s idegrees F limit for startup Idle recirc loop. Pressure was allowed to decrease below l l I

3 s condensate booster pump pressure and allowed condensate feedwater to be injected intc j i i

3 7 l reactor vessel. This resulted in a cooldown rate of 103 degrees F Per hour in a one  ; j i

ois l hour period in the A recirc loop. Condensate booster pump was tripped and (con't)  ; }

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[7l7l7l7lg 44 47 CAUSE CESCR!PTioN AND CCRREC'nVE ACTIONS h 3 0 jFollowing a reactor scram personnel were cooling down vessel using RCIC to bring recirci ',

1 3 i l loop A within 50 degrees F limit for startup of B recirc pump. Pressure was allowed . g

, 7 jto decrease below condensate booster pump discharge pressure causing injection of  ;

, 3 { condensate water into vessel thus causing rapid cooldown of reactor coolant tempera-  ;

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t Personnei have been cautioned abcat reactor pressure decreases below  ;

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• Georgia Power Company .

Edwin I. Hatch Plant Baxley, Georgia 31513 Event Description and Probable Consequences (cen't) feedwater valves isolated to stop injection to vessel. Recirc icop A temperatures were back within limits within 15 minutes. There were no personnel injuried or overexposured or any release of radioactive materials te the environs as a result of this occurence.

Cause Description and Corrective Actions (con't) a system pressure that could inject cold feedwater into vessel during reactor cooldown and to observe pressure decrease and level increase ve.'y closely during this type pf operation.

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