ML18139A964

Ro:On 801220 at Full Power,Condenser Cooling Water Outlet Temp Exceeded Max Rate of Change Per Tech Specs.Cause Not Stated.Temp Decreased When Waterbox Outlet Valves Throttled Due to Vacuum Priming Problems

ML18139A964
Person / Time
Site:	Surry
Issue date:	01/05/1981
From:	Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, Varga S Office of Nuclear Reactor Regulation
References
NUDOCS 8101090474
Download: ML18139A964 (1)

Text

VIRGINIA ELECTRIC AND POWER COMPANY R:tCHMOND,V:tRG:tNJ:A 23261 January 5, 1981 Mr. Harold R. Denton, Director Serial No. 006 Office of Nuclear Reactor Regulation NO/RMT:jmj Attn: Mr. Steven A. Varga, Chief Docket No.: 50-~81 Operating Reactor Branch No. 1 License No.: DPR-37 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Denton:

This letter report is submitted in accordance with the provisions of Surry Power Station Technical Specification 4.14.C.l.

During the period from 1600 to 1700 on December 20, 1980, the condenser's cooling water outlet temperature exceeded the maximum average rate of change of 3°F/hr permitted by Technical Specification 4.14.A.3. The average rate of change during this period was 8°F/hr. However, the duration of each step change was only 15 minutes and the maximum change in cooling water temperature was 50F. At the time of this event, Unit No. 1 was at cold shutdown and Unit No. 2 was at 100% power.

Condenser cooling water outlet temperature increased about 4°F during a 15 minute period and decreased about 5°F during the following 15 minute period.

This perturbation occurred when waterbox outlet valves were being throttled due to station vacuum priming problems.

A search was conducted to determine if the temperature change had affected the river environment. No detrimental evidence was found.

Operation with reduced station discharge cooling water flows and cold river temperatures will magnify the effect of waterbox valve operation. Extreme care in the operation of the circulating water system should prevent recurrence.

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