ML20236S660

NPDES Notification of Wastewater Discharge Permit Violation: on 980623,Rancho Seco Laboratory Records Indicate Combined Plant Effluent Ph Greater than Supply Water Ph.Caused by Improper Reporting of Ph Values.Reviewing Existing Methods

ML20236S660
Person / Time
Site:	Rancho Seco
Issue date:	07/20/1998
From:	Redeker S SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Merschoff E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
MPC&D-98-119, NUDOCS 9807270153
Download: ML20236S660 (2)

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SACRAMENTO MUNICIPAL UTluTY DISTRICT O 6201 S Street, P.o. Box 15830, Sacramento CA 95852 1830,(916) 452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CAllFORNIA MPC&D 98-119 -

L JUL 211998

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JUL 2 0 l-j DNMS U. S. Nuclear Regulatory Commission

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Attn: E. W. Merschoff, Regional Administrator Region IV Parkway Central Plaza Building 611 Ryan Plaza Building, Suite 400 Arlington, Texas 76011-4085 Docket No. 50-312 Rancho Seco Nuclear Station License No. DPR-54 REPORT OF COMBINED PLANT EFFLUENT pli GREATER THAN Tile SUPPLY WATER pH; NPDES PERMIT NUMBER CA0004758

Dear Mr. Merschoff:

In accordance with a condition specified in the NRC Safety Evaluation Report for License Amendment No. 45 to Facility Operating License No. DPR-54, the District is required to notify j

the NRC concerning Rancho Seco NPDES wastewater discharge perrnit violations. Below, the District provides information the Rancho Seco combined plant effluent pH being reported as greater than the supply water pH, which was reported as greater than 8.5.

In accordance with NPDES Permit No. CA0004758, the combined plant effluent pH may be g

greater than 8.5, if the supply water pH is equal to or greater than the combined plant effluent pH.

The permit allows this because the Rancho Seco combined plant effluent is approximately 99.99%

supply water. For June 23,1998, Rancho Seco laboratory records indicate the combined plant effluent pH was 9.01 while the supply water pH was 8.78. This constitutes a NPDES permit j

violation since the combined plant effluent pH was reported as both greater than the supply water pH and greater than 8.5.

The District investigated the reported high pH value to try to determine if a release of a caustic element caused the reported pH values. The District could find no evidence that a caustic j

element scenario occurred. The District believes laboratory personnel improperly reported the l

pH values and that the reported values are analytical errors.

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9807270153 900720 PDR ADOCK 05000312 S

pop is-1s29 RANCHO SECO NUCLEAR GENERATING STATION D 14440 Twin Cities Road, Herald, CA 95638-9799;(209) 333-2935 a

Mr. Merschoff MPC&D 98-119 Existing administrative controls are designed to identify analytical errors through resample to invalidate or confirm initial, suspect results. Unfortunately, the District did not identify this l

potential NPDES violation situation until June 25,1998. The District took both a combined j

plant effluent and supply water sample on June 25,1998, and confirmed the proper pH -

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relationship (i.e., supply water pH > combined plant effluent pH > 8.5).

. Rancho Seco laboratory personnel are performing a review of the existing analytical methods and

' administrative controls for pH analyses. The District's objective is to implement appropriate

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corrective actions that provide assurance the analytical errors experienced on June 23,1998, will -

i not be repeated.

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Members of your staff mquiring additional information or clarification may contact Mr. Richard l-Mannheimer at (916) 452-3211, Extension 4916.

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Sincerely i

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n Steve J. Redeker Manager Plant Closure and Decommissioning cc:

V.Everett,NRC, Arlington, Texas l-i I

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