ML20058G029

NPDES Noncompliance Notification:On 931122,discovered Leak in Closed CCS Which Determined to Contain 0.36 Parts Per Million Cr-04.Caused by Addl HX Tubes in Same Component as Similiar Leak Reported on 931102.Leaking Tubes Plugged

ML20058G029
Person / Time
Site:	North Anna
Issue date:	11/30/1993
From:	Marshall B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Loyd K VIRGINIA, COMMONWEALTH OF
References
NUDOCS 9312090078
Download: ML20058G029 (2)

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• EETURN RECEIPT REOUESTED VIRGINIA POWER November 30, 1993 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:

l As Mr. Daniel James of my staff discussed with you by telephone on November 22, 1993, 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.

Early Monday morning (November 22) Operations personnel realized there was a leak in the closed component cooling system. They immediately isolated the system and took actions to determine the source of the leak. This leak was into the Unit 1 blow-down which is released, untreated, via the clarifier (Outfall 003) to the circulating water tunnel. A routine sample had been taken from the clarifier at 0400 Monday, which was prior to the isolation of the component cooling system. This sample was tested and determined to contain 0.36 parts per million chromate (Cr04). It was calculated that the daily release of chromate was approximately 0.6 lbs., and Operations personnel estimated the system had been leaking for several days.

The source of the chromate leak was found to be additional heat exchanger tubes in the same component as the similar leak reported on November 2, 1993. Leaking tubes in the heat exchanger have been plugged to stop the loss of chromate from the system.Options Studies are underway to determine a long term solution. being considered include additional repair or replacement of tubes. It is projected that this may be accomplished within the next few weeks. ,

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l Mz;. Ke'mper Loyd November 30, 1993 Page 2 Until more permanent repairs are completed, the blow-down tank which receives leaks from the component cooling system will be sampled every four hours, when the Unit 1 blow-down vent condenser is in service, and analyzed for chromate. If chromate is detected in the tank, the system can be isolated to prevent additional untreated releases to the clarifier.

As with the previous loss of chromate from this system, no other contaminants were involved and no violations of any permit limitations occurred. Site visual inspections revealed no evidence of environmental damage in the station's discharge canal or the l vaste heat treatment facility. 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 waste heat treatment i facility, or at the station's discharge to state waters.

Should you desire additional information or have any questions about this matter, please contact Daniel James at (804) 273-2996. j Sincerely, L t- -

B. M. 2frshall, 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. Nuclear Regulatory Commission 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