ML20059E383

Follow-up to NPDES Noncompliance Notification:On 931006,12 & 19,fecal Coliform Exceedances Occurred at Outfall 003 Due to High Chlorine Demand from Nitrate Interference & Seasonal Turnover in Lagoon.Sandfilter Pumps Modified

ML20059E383
Person / Time
Site:	Mcguire, McGuire
Issue date:	10/26/1993
From:	Atherton N DUKE POWER CO.
To:	Gleason R NORTH CAROLINA, STATE OF
References
NUDOCS 9311030183
Download: ML20059E383 (4)

Text

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8 k I Duke Ibwer Company Genemtion Services Department 0339 liagets Ferry Road Huntersudle, NC280781929

) DUKEPOWER October 26, 1993 Mr. Rex Gleason Regional Manager Water Quality Section Department of Environment, Health and Natural Resources 919 North Main Street Mooresville, N.C. 28115

Subject:

McGuire Nuclear Station NPDES Permit NC0024392 Fecal Coliform Exceedances File: MC 702.13 Certified: P 384 361 055

Dear Mr. Gleason:

Pursuant to Part II, Section D(6)(d) of the subject permit, this is a follow-up written report to the North Carolina Department of Environment, Health and Natural Resources for recent fecal coliform exceedances at Outfall 003 of McGuire Nuclear Station. The initial notifications were made to Mr. Mike Parker on October 11 and 13, and to Mr. G.T. Chen on October 21, 1993, by Norma Atherton of Duke Power Company. -

McGuire Nuclear Station's domestic and sanitary treatment system (Outfall 003) exceeded the permitted daily maximum limit of 400 col. /100ml for fecal coliform samples collected on October 6,12, and 19,1993. The values observed on these samples were 1600 col./100ml, >2400 col./100ml and >2400 col./100ml respectively. The repeat sample collected on October 14, 1993, was negative for fecal coliform.

From our preliminary test results, the cause of these exceedances appear to be related to a high chlorine demand from nitrate interference and seasonal turnover in the lagoon. Since the Sanuril chlorinator was working at its maximum capacity, options which could provide additional chlorination and disinfection were discussed with your office on October 14,1993. Several measures have been taken in order to mitigate these exceedances.

A temporary receptacle containing additional Sanuril chlorine tablets has been added to the chlorination contact chamber to provide additional disinfection. Also, solids were removed from the chlorine contact chamber and chlorinator which were interferring with disinfection. The sandfilter pumps were modified to provide lower flow rates and maintain an uninterrupted discharge during lower flow periods. ,

Additionally, the sanitary lagoon is scheduled for its routine sludge removal in mid l

November. Presently, we are awaiting approval from the State for disposal of the l slu d ge.

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Since the sanitary system discharges into the Waste Water Collection Basin and does not discharge directly to receiving waters, there was no environmental impact as a result of this incident. In addition, the discharge from the sanitary system was isolated from October 8 to 10,1993, October 16 to 18, and from October 22 to 24,

.1993.

If you should need additional information or have questions, please contact Norma Atherton at (704) 875-5963.

Sincerely,

%wnw Y' Wb "

Norma G. Atherton, Scientist Environmental Division, Water Protection Group Generation Services Department cc: Mr. Randy Kepler - NCDEHNR - Raleigh, N.C.

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U.S. Nuclear Regulatory Commission 101 Marietta St. , NW, Suite 2900 Atlanta, Georgia 30329 Mr. George Maxwell NRC Resident Inspector McGuire Nuclear Station 12700 Hagers Ferry Road Huntersville, N.C. 28078-8985 l

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