ML20058L225

Submits One Major & Two Minor Comments Re Draft EIS for Facility

ML20058L225
Person / Time
Site:	Monticello
Issue date:	07/03/1972
From:	Ward E NORTHERN STATES POWER CO.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9105130404
Download: ML20058L225 (2)

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i MSD NORTHERN S T J. T E S POWER COMPANY July 3, 1972 ,

_ f, hi, Deputy Director for Reactor Projects

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Directorate of Licensing _'

U. S. Atomic Energy Commission T~T C Washington, D. C. 20545 \mO '. l ' - ' *

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Gentlemen:

e MONTICELLO NUCLEAR CENERATING PLANT E-5979 j ; ~,.77  % -

t.c Docket No. 50-263 Comments on Draft Environmental Statement -

l We have reviewed the Draft Environmental Statement for our Monticello Plant recently l issued by your office. We find the tona of the statement very favo n.ble w the {

environmental impacts are 3 1.ced in good perspective. However, pursuant to the comment opportunity afiorded in the Notice of Availability published in the l Federal Register of June 2, 1972, we are conveying one major comment and tv.  ;

minor comments in the following paragraphs. j l

In the Draft Environmental Statement, page iii, paragraph 6 (c), it is recommended: l "The applicant should take appropriate actions as necessary to assure that the release of radioiodine to the atmosphere meets the require-ments of the proposed Appendix I,10 CFR 50, as fomalized."

We have analyzed the estimated release of radiciodine to the atmosphere based on realistic assumptions and conclude that the resulting dose levels will be less than those proposed in Appendix 1. The large discrepancy between our estimates based on operating experience, and the AEC's estimates, results from the conser-vative approach used by the AEC.

We are continuing to perform a comprehensive environmental surveillance program in cooperation with the Minnesota Department of Health. This program includes i the monitoring of radioiodine releases to the atmosphere, the monitoring of 131 1 airborne concentrations and 1311 raw milk concentrations within a ten mile radius of the plant. The resultsof these monitoring programs substantiate our estimates of radioiodine doses. The continuing environmental surveillance program will assure our co=pliance with the requirements of proposed Appendix I.

Our enalysis of the effect of radiciodine releases is based upon realistic  !

assumptions, supported by operating experience, that are different from the j assumptions appearing in Table III-3, page 111-16 of the Draft Environmental Statement. In particular our analysis utilizes an average off-gas stack release ,

i rate of 25,000 pCi/sec (af ter 30 minute hold-up) as contrasted with the AEC off-gas rate of 44,000 pCi/sec (Based upon a 100,000 pCi/sec release for a 3,400 mWt reactor). The 25,000 pCi/sec average release rate was utilized in the Monticello hO 404 7po793 DCK 05000263 CF

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N O RT.. .RN CTATED POWER Coh ANY Environmental Report, page 11-18, and is consistent with existing and expected plant operating experience.

In addition to the lower off-gas rate, we have utilized a primary system steam Icakage rate of 240 pounds per hour (1b/hr) instead of the 2,400 lb/hr leak rate listed in Table III-3 of the Draf t Environmental Statement. This 240 pound per hour leakage is b sed on a 107. steam component of the turbine building Icak rate of 2,400 lb/hr total water, projected by the plant vendor. This leak rate esti-mate is supported by operating data concerning measured iodine releases as presented in our Six Month Operating Reports.

Based on the 240 lb/hr prinary system steam leak rate, the 25,000 uCi/ sec of f-gas release rate, and utilizing the other AEC assumptions in Table III-3, we estimate a thyroid dose rate to an infant drinking milk from a cow located at the nearby farm (reference on page V-28 of the Draft Environmental Statement) would be less than the 5 mrem /yr guideline set forth in Appendix I. This dose rate is contrasted with the calculated 67 mrem /yr dose presented on page V-28 of the Draft Environmental Statement. In actuality there are no dairy cows located at the nearby farm mentioned above and current field investigations show that the nearest dairy farm is located 1.5 miles northwest of the plant.

A similar computation for this farm location would yield a much further reduced thyroid dose rate, On page III-7 (paragraph 2) of the Draf t Environmental Statement it is indicated that "NSP has made a commitment to the MPCA to operate the cooling towers to the maximum extent practical." In a recently formalized commitment, NSP has agreed to operate the cooling tower system in a helper rode when the ambient river temperature upstream of the intake consistently exceeds 680F and the helper node will be discontinued when the river temperature drops below 680F.

On page XI-6 (paragraph 4) of the Draft Environmental Statement it is indicated that the cost of the plant off-gas modifications will exceed $3,000,000.

Currently we estirmte the cost of these additional facilities to be in excess of $4,500,000.

We trust the above comments will be taken into account in preparation of the Final Environmental Statement.

Yours very truly, (CD E C Ward, Director Engineering Vice Presidential Staff CC Gerald Charnoff l Donald E Nelson 1

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