ML20063H520

NPDES Noncompliance Notification:On 940125,facility Experienced Unusual Discharge of Chromate to Clarifier from Leak in Component Cooling Sys.Caused by Defective HX Tubes. Leaking Tubes Replaced to Stop Loss of Chromate from Sys

ML20063H520
Person / Time
Site:	North Anna
Issue date:	01/31/1994
From:	Marshall B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Loyd K VIRGINIA, COMMONWEALTH OF
References
NUDOCS 9402180199
Download: ML20063H520 (2)

Text

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Mr. Kemper Loyd Valley Regional Office Department of Environmental Quality 116 North Main Street P. O. Box 268 Bridgewater, VA 22812 RE: NORTH ANNA POWER STATION - VPDES PERMIT NO. VA0052451 UNUSUAL DISCHARGE

Dear Mr. Loyd:

As Mr. Daniel James of my staff discussed with you by telephone on January 25, 1994, the North Anna Power Station experienced an unusual discharge of chromate to the clarifier from a leak in the component cooling system. The clarifier discharges to the circulating water tunnel via Outfall 003.

At the time the chromate leak was discovered, analysis of samples from Outfall 003 showed 0.16 ppm at the internal discharge point.

Chromate inventory calculations indicate that the leakage probably occurred over four days at a rate of 0.3 pounds per day.

The source of the chromate leak was found to be the component cooling system heat exchanger tubes which were replaced following similar leaks reported in November 1993. The replacement tubes were apparently defective. Leaking tubes in the heat exchanger have been replaced to stop the loss of chromate from the system.

While the system is being evaluated to determine if additional tubes will require replacement, the blow-down pump discharge which receives leaks from the component cooling system will be sampled every four hours and analyzed for chromate. If chromate is detected in the pump discharge, the system can be isolated to prevent additional untreated releases to the clarifier.

As with the previous losses of chromate from this system, no other contaminants were involved and no violations of any permit limitations occurred. The chromate present in the water discharged would not be expected to be detectable in the discharge canal or the waste heat treatment facility, and would have no impact on water quality in the canal, the vaste heat treatment facility, or ,

at the station's discharge to state waters.

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a Mr. Kemper Loyd January 31, 1994 Page 2 Should you desire additional information or have any questions about this matter, please contact Daniel James at (804) 273-2996.

Sincerely, B. M. Marshall, P.E.

Manager Water Quality cc: U.S. Nuclear Regulatory Commission Region II 101 Marietta St., NW Suite 2900 Atlanta, GA 30323 RE: North Anna Units 1 & 2 Docket Nos. 50-338/50-339 License Nos. NPF-4/NPF-7

.U.S. NuclearLRegulittbry~Uda$tission Document Control Desk Washington, DC 20555 RE: North Anna Units 1 & 2 Docket Nos. 50-338/50-339 License Nos. NPF-4/NPF-7 Mr. R. D. McWhorter NRC Senior Resident Inspector North Anna Power Station l

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