ML19093B352
| ML19093B352 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/06/1976 |
| From: | Stallings C Virginia Electric & Power Co (VEPCO) |
| To: | Reid R, Rusche B Office of Nuclear Reactor Regulation |
| References | |
| Download: ML19093B352 (1) | |
Text
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April 6, 1976:
Mr. Benard c. Rusche Serial No. 966 PO&M./ ALH: j lf
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Director of Nuclear Reactor Regulation
- u. s. Nuclear Regulatory Connnission Washington D.c.
20555 Attn:
Mr. Robert w. Reid, Chief Operating Reactors Branch 4 Docket Nos.
50-280 50-281 License Nos. DPR-32
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Dear Mr. Rusche:
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In accordance with Technical Specification 4.14.C.1 for Surry Power Station, this report describes an occurrence during which the difference be-tween the river water ambient temperature measured at the station high level intake and cooling water at the discharge control structure exceeded 15 degrees F.
At the time of the occurrence both Units 1 and 2 were operating at 100 percent power.
On March 26, 1976, at approximately 1915 the temperature difference (~T) across the station exceeded 15 degrees F.
The condenser outlet circulating water valves, which had been throttled to maintain the inlet canal level at 23.5 feet, were opened fully to increase water flow through the con-denser.
This action reduced the temperature difference to within 15 degrees at 1935. At no time did the station~ T exceed 15.5 degrees F.
The temperature increase was caused by a rapid drop in the river water ambient temperature.
This rapid cooling was the result of river tidal action and the natural cooling of river water that occurs during the afternoon and evening hours.
Radical temperature fluctuations in river water ambient temperature such as encountered in this instance, make it extremely difficult to predict when action is necessary to avoid the 15 degrees F increase across the station.
There was no evidence of any adverse environmental from this occurrence.
cc:
Mr. M. V. Sinkule Very truly yours,
- c. M. Stallings Vice President-Power Supply and Production Operations