ML19105A178
| ML19105A178 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/01/1976 |
| From: | Stallings C Virginia Electric & Power Co (VEPCO) |
| To: | Reid R, Rusche B Office of Nuclear Reactor Regulation |
| References | |
| Serial No. 959 | |
| Download: ML19105A178 (2) | |
Text
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VIRGINIA ELECTRIC AND POWER COMP RICHMOND,VIRGINI.A 23261 April 1, 1976*
Mr. Benard C. Rusche Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555 Attn:
Mr. Robert W. Reid, Chief Operating Reactors Branch 4
Dear Mr. Rusche:
Serial No. 959 PO&M/ALH:clw Docket Nos. 50-280 50-281 License Nos. *DPR-32 DPR-37 In accordance with Technical Specification 4.14.C.l for Surry Power Station, this report describes two occurrences during which the difference between 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 first occurrence, both Unit Nos. 1 and 2 were operating at 100 per cent power.
On March 22, 1976 at approximately 0015 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> the temperature difference (6T) across the station exceeded 15 degrees F. A power reduction was initiated on Unit No. 2 at 0015 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> and on Unit No. 1 at 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> to reduce and maintain the temperature difference across the station with-in 15 degrees F.
At no time did D.T exceed 15.7 degrees F.
At the time of the second occurrence both Unit Nos. 1 and 2 were operating at 100 per cent power.
On March 23, 1976 at approximately 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> the temperature difference (6T) across the station exceeded 15 degrees F.
The duration of operation with the station D.T in excess of 15 degrees F was.approx-imately 30 minutes.
The maximum station D.T during this period was 16 degrees F.
The temperature increase during both occurrences 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 those encountered in these instances make it extremely difficult to predict when action is necessary to avoid the 15 degree F increase across the station.
3431
VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. Benard C. Rusche Page 2 There was no evidence of any adverse environmental impacts resulting from these occurrences.
Very truly yours,
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C. M. Stallings Vice President-Power Supply and Production Operations