ML20137G231

Forwards Results of Bioassay Testing on LCS-1000 & Submits Requested Info Re Implementation Schedule for Molybdenum

ML20137G231
Person / Time
Site:	Millstone
Issue date:	03/25/1997
From:	Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES SERVICE CO.
To:	Grier J CONNECTICUT, STATE OF
Shared Package
ML20137G236	List: ML20137G231 ML20137G249
References
D10904, SES-97-GN-048, SES-97-GN-48, NUDOCS 9704010357
Download: ML20137G231 (3)

Text

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107 seiaco stnet, serim. cr 06037 g[\ Northe st Utilities System 3.o + t m see %

, P.O. Box 270 i llarticrd. CT 06 41-0270 (203) 665-5000 March 25,1997 SES-97-GN-048 l 1

D10904 Mr. James Grier Supervising Sanitary Engineer ,

Water Management Bureau Department of Environmental Protection ,

79 Elm Street j Hartford, CT 06106-5127

Dear Mr. Grier:

Millstone Station NPDES Permit No. 0003263 Sucolemental Information and Implementation Schedule for Molybdenum

References:

Letter D10726 from S. Scace to J. Grier dated January 24,1997 Letter D10765 from S. Scace to J. Grier dated February 5,1997 Letter D10812 from S. Scace to J. Grier dated February 12,1997 Northeast Nuclear Energy Company (NNECO) recently submitted information in support of its request to use LCS - 1000 as a corrosion inhibitor in the Millstone Unit 1 Closed Cooling Water Systems (References). A letter of approval was received from your office dated February 14, 1997 authorizing the use of LCS-1000 in Unit 1. Prior to this approval, we agreed to provide the results of bioassay testing on LCS-1000 once the results were received. We also discussed with you the implementation schedule for this project and agreed to provide you with further information in this regard. The following provides the Department with the requested information.

1) Schedule At present, the phase-in of LCS-1000 in the Reactor Building Closed Cooling Water System is expected to commence during the week of March 31,1997. This will be followed by the phase-in of LCS-1000 in the Turbine Building Secondary Closed Cooling Water System which is scheduled to commence the week of April 15,1997. The phase-in of LCS-1000 is expected to be completed on or before June 10,1997 with the introduction into the Turbine Building Closed Cooling Water System.

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' 2) Testina Toxicity tests have been completed on the formulation of LCS-1000 that contained no sodium I carbonate, as referenced in the supplemental information letter dated February 12,1997 (D10812). This is the formulation that will be used at Unit 1. Attachment 1 contains the results of these toxicity tests.

The Acute No Observed Effect Level (ANOEL) for the LCS-1000 used in Unit 1's Closed Cooling Water Systems based on the more sensitive species tested (ie. bay mysid) is 1,292 mg/l. The Chronic No Observed Effect Level (CNOEL)is 194 mg/l. The ANOEL and CNOEL for the original formulation reported to you on February 5,1997 were 1,793 and 269 mg/l respectively.

Comparison of the toxicity testing of the two formulations of LCS-1000 indicates a difference in the bioassay results, but the magnitude of difference does not change the conclusions of the environmental assessment upon which DEP's approval was based.

Should you have any questions or concerns regarding the above, please contact Mr. Paul Jacobson at (860) 447-1791 x2335.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY ram S. Scace Director - Nuclear Engineering Programs cc: M. Harder; NRC I

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Attachment 1.

1 Toxicity Test Results for LCS-1000 Containing No Sodium Carbonate l

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