ML19208B199

First Interim Deficiency Rept Re Ice Condenser Heat Loads Exceeding Design Heat Loads.Could Cause Degradation of Ice in Ice Condenser & Invalidate Safety Analyses.Reasons for Necessity to Operate Four Glycol Chillers Being Studied

ML19208B199
Person / Time
Site:	Sequoyah
Issue date:	09/11/1979
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19208B194	List: ML19208B193 ML19208B199
References
NCR-NEB-79-1, NUDOCS 7909190342
Download: ML19208B199 (1)

Text

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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 ICE CONDENSER HEAT LOADS EXCEED DESIGN HEAT LOADS NCR NEB 79-1 10 CFR 50.55(e)

FIRST INTERIM REPORT Description During hot functional testing of Sequoyah Nuclear Plant unit 1, it was discovered that four glycol chiller units were required to maintain the required 15 F ice bed temperature. The Sequoyah Nuclear Plant design called for three glycol chillers to be sufficient to maintain the ice bed temperature at 15 F. Based on the performance of unit 1 ice condenser, the present glycol refrigeration capacity (i.e., four glycol chiller units per nuclear unit) may be insufficient to sustain acceptable ice bed temperatures in both ice condensers during unit 2 ice loading.

This deficiency is reportable because with the present glycol chiller capacity, ice loading of unit 2 might allow temperatures in the ice condensers to rise above 15 F. I" temperatures in the ice condenser were to rise above 15 F, it is possible that the ice might be degraded.

Degradation of the ice in the ice condenser could adversely affect the safe operation of the plant because the safety analyses for the plant are based on a specific weight and configuration of ice in the ice con-denser. Deviation from this specific weight and sonfiguation could invalidate the safety analyses for Sequoyah Nuclear Plant.

The design of the ice condenser for Watts Bar Nuclear Plant is similar to the ice condenser design for Sequoyah Nuclear Plant; therefore, the possibility of a similar deficiency exists at Watts Bar Nuclear Plant.

This possible deficiency at Watts Bar Nuclear Plant is being investigated.

Corrective Actions Operation or four glycol chillers units has maintained the unit 1 ice condenser temperature acound 15 F. TVA has begun to investigate the reasons for the necessity to operate four glycol chillers to maintain 15 F in the unit 1 ice condenser.

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