ML20078H915

NPDES Noncompliance Notification:On 950120,structural Failure of Fiberglass Tank Allowed Water Containing H-901-G to Spill Into Chemical Addition Bldg Sumps.Reason(S) for Equipment Failure & Necessary C/A Under Investigation

ML20078H915
Person / Time
Site:	North Anna
Issue date:	01/26/1995
From:	Marshall B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Pandey J VIRGINIA, COMMONWEALTH OF
References
NUDOCS 9502070101
Download: ML20078H915 (2)

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, Innsbrook Technical Center 5000 Dominion Bouletard y' Glen Allen. Virginia 23060 i j

l CERTIFIED MAIL RETURN RECEIPT REOUESTED January 26, 1995 ,

Janardan R. Pandey l Valley Regional Office 1 Department of Environmental Quality P. O. Box 268 Bridgewater, VA 22812 Re: North Anna Power Station - VPDES Permit No. VA0052451 Unusual Discharge 1-20-95

Dear Dr. Pandey:

This is in follow up to the telephone notification made to Mr.

Larry Simmons on January 20, 1995, of an unusual discharge experienced at North Anna Power Station.

The chemical addition building near the service water reservoir at North Anna Power Station houses a fiberglass tank in which a Calgon product designated as H-901-G is mixed with water to form hypobromous acid for use as a water disinfectant in the service water system. At about 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on January 20, a structural failure of the tank allowed water containing H-901-G to spill into the building sumps. The sump pumps did not activate and the water overflowed into a stormwater ditch to the discharge canal. The j i

l discharge entered the canal about 100 yards downstream of Outfall 004.

The discharge consisted of an estimated 3,000 gallons cf water. ,

The concentration of the H-901-G in the water released was 0.3 mg/l I measured as Total Residual Chlorine (TRC). The water in the discharge canal was also sampled about one foot from the point of entry and the TRC results were "non-detectable" (less than 0.1 mg/l TRC). The discharge was immediately brought under control and did not continue beyond the initial volume lost.

Station personnel inspected the discharge canal in the vicinity of the discharge point and did not observe any evidence of l

environmental problems from the discharge nor was there any l indication of the abnormal discharge. Due to the unstable nature I of the hypobromous acid and the low concentration present, the material would have been quickly assimilated and neutralized in the receiving waters of the discharge canal.

i 9502070101 950126 8 i DR ADOCK 0500 g

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r Janardan R. Pandey January 27, 1995 Pa'ge 2 To provide perspective in evaluation of this event, we would like to point out that this unusual discharge entered the discharge canal in the same vicinity as the permitted effluent from the main sewage treatment plant. The STP effluent (Outfall 011) has a much greater flow rate than the volume of the accidental discharge and

'm permitted a TRC maximum of 4.0 mg/1; the normal range is 1.0 tnrough 2.0 mg/1. Therefore, although not routed to a normal outfall point, the discharge from this event did not exceed any permitted ef fluent limitations. Also, this discharge was internal to the station's final discharge point, not directly to state I waters.

The reason (s) for the equipment failures causing this event and the necessary corrective actions are under investigation. The sump pumps are now in full operation. The tank will remain isolated ,

until any other necessary corrections to prevent recurrence of this  !

event are completed.

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

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l _

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 1 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

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