ML20041F536

Discusses Proposed Use of Continuous Low Level Chlorination in Intake Tunnel at Facility

ML20041F536
Person / Time
Site:	Seabrook
Issue date:	03/11/1982
From:	Stickney W ENVIRONMENTAL PROTECTION AGENCY
To:	Wheeler D NRC
References
NUDOCS 8203170106
Download: ML20041F536 (2)

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY (D N REGION l J J. F. KENNEDY FEDERAL BUILDING BOSTON, MASSACHUSETTS 02203 N vb p

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March 11, 1982 C , mag.?67g L~

Mr. Duke hheeler g%er U.S. rJuclear Ibgulatory Comnission .,

Washington, DC 20555 \g @

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Dear Mr. Wheeler:

We have reviewed the Public Service Company of 11ew Ilanpshire subnittal concernity the proposed use of continuous low level chlorination in the intake tunnel at Seabrook Station. We believe that the followirg information is necessary in order to completely describe the impacts.

1. An explanation of the reasons for proposing this new procedure (safety, cost, etc. ) over the previously considered thermal back-flushirg operations.

2. A block dia3 ram showirg the water usage, the process equipnent, the chlorine injection points, the sampliry points, residence time in each section of the system, and expected chlorine concentrations.

3. We chlorine demand of the salt water er.terirg the tunnel should be estimated.

4. %e chlorine measurement parameters should be specified. Either total residual chlorine / oxidants (as required by Steam Electric Guidelines 40 CFR 423) or free available chlorine / oxidants should be used. For convenience, the term " chlorine" will be used for both " chlorine" and " oxidants" in this letter.

5. %e term " release of 0.2 ng/l" chlorine can be interpreted to be either into the discharge transition structure or into the Atlantic Ocean.

His should be clarified.

6. %e Company has correctly indicated that the effluent would be diluted with a 10 to 1 ratio of cooling water when the heated discharge leaves the diffuser; however, no mention is made of the instantaneous chemical reaction of the residual chlorine with the chlorine demand of the passively entrained water and the implication this may have for the residual in the discharge.

7. Frequency, dosaje, or duration of chlorine injections into the circulatirg and water service pumps should be provided.

8. 011orine concentrations expected in the discharge transition structure due to the shock dosajes of chlorine added to the circulatirg water and service water and the continuous chlorination at the intake structure should be provided.

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9. 'Ihe estimated toxicity of the discharge at the lip of the diffuser and the toxicity of the discharge after mixiry and reactirg with the entrained water should be related to the data originally presented in the Final Environmental Impact Ibport for Seabrook, Partgraph 5.5.2.3 "Glorine" or to the more recent work of Mattice and Zittel in 1976 or Mattice in 1977.

10. 'Ihe work of Mattice and Zittel which shows that concentrations as low a'; 0.02 m3/1 of chlorine prevented the attachment of mussels shou.1d be noted and discussed .

11. 'Ihe Glorine Minimization Program which the Company will undertake to reduce the amount of chlorinated conpounds that are discharged to the receivirg waters should be described.

12. Data should be provided on the relationship between thermal back-flushing operation and chlorination. Nill each be used and with what frequency? -

13. IIalogenated compounds that can be expected in the diffuser discharge should be identified and their effects described.

Our propsed NPDES permit and a description of how we propose to handle the EPA permit process will be sent to you before the end of next week. We wauld like to review the final water quality section before it is printed. We can travel to your office to do this if timing is a prthlem for you.

Sincerely, T '

LQ wil .<a 3 Wallace E. Stickney, P.E.

Director thvironmental Impact office cc: Public Service Company of New thmpshire