ML19261E670

Forwards Repts, Supplementary Info,Hydrogeologic Evaluation of Const Dewatering & Summary Rept & Testing Investigation & Testing for Groundwater Pressure Relief During Const.

ML19261E670
Person / Time
Site:	Bailly
Issue date:	08/27/1979
From:	Bohn R NORTHERN INDIANA PUBLIC SERVICE CO.
To:	Ballard R Office of Nuclear Reactor Regulation
Shared Package
ML19261E671	List: ML19261E670 ML19261E675 ML19261E679
References
NUDOCS 7908300494
Download: ML19261E670 (2)

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onesco Northern Indiana Public Service Company Nuclear Staff RR #3, Box 501 Chesterton, IN 46304 August 27, 1979 BAILLY GENERATING STATION N-1 Mr. Ronald Ballard, Chief Environmental Projects Branch No. 1 Office of Nuclear Regulatory Cormdssion U.S. Nuclear Regulatory Commission Washington, D.C. 20545 RE: NORTHERN INDIANA PUBLIC SERVICE COMPANY BAILLY GENERATING STATION NUCLEAR 1 DOCKET NO. 50-367

Dear Mr. Ballard:

Enclosed herewith are twenty-five (25) copies of a report titled

" Supplementary Information,Hydrogeologic Evaluation of Construction Dewatering" dated August 27, 1979, for Bailly Generating Station Nuclear 1. This report provides supplementary information to the report submitted with our letter of April 3,1978, and our responses dated July 20, 1978, to your questions of May 19, 1978.

Subsequent to the installation of the dewatering system and ground-water monitoring system described in our above-mentioned submissions, which the NRC found acceptable (see your letter dated September 19, 1978), we have accumulated considerable on-site data from operating the system and recording data developed by the monitoring program. In addition, a test well was installed and operated to help determine whether the installed system would accomplish its designated function.

The accumulated data have confirmed that prior calculations of the quantities of water to be removed from the excavation are correct.

However, the data have also indicated that one portion of the installed system--the free flowing drains installed to relieve pressure in the cdnfined aquifer--has not been as effective as had been expected. Accordingly, for this purpose an alternative mechanism will be installed which is described in the enclosed report. The alternative mechanism will remove approximately the same quantities of water as had previously been calculated and will not affect previous projections of minimal groundwater drawdown at the site boundary.

The ability of the existing monitoring system to detect such effects and the ability of the recharge system to mitigate such effects, if required, remains unchanged.

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Mr. Ronald Bal'.ard August 27, 1979 (Our present schedule calls for installing the alternative mechanism in early September) . Please let us know if you need any additional information on these matters.

Sealing of the ash ponds for Bailly Units 7 and 8 is scheduled to begin in March 1980. Installation of the pond liners is expected to be completed within six months thereafter. A report describing the methods to be used in monitoring the effects of the ash pond sealing on groundwater levels across the Bailly N-1 site is being prepared and will be submitted at least 60 days before sealing begins.

Sincer 5-( (7 R. Bohn Manager, Nuclear Staff RJB/mlk Enclosures CC: Mr. W. II. Eichhorn, Esq.

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