ML20195H614

Forwards Suppl to 1985 Technical Evaluation Memo,Per Request for Review of Proposed Mod 1 to Remedial Actions at Salt Lake City/Clive Site.Proposed Design Will Continue to Meet long-term Stability Requirements of 40CFR192

ML20195H614
Person / Time
Issue date:	06/02/1988
From:	Tokar M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Fliegel M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
References
REF-WM-41 NUDOCS 8806280326
Download: ML20195H614 (5)

Text

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1 MEMORANDUM FOR: Myron Fliegel, Section Leader Operations Branch Division of Low-Level Waste Management and Deconinissioning, HMSS

'FROM: Michael Tokar, Secti Leader Technical Branch Division of low-Level Waste Management and Decommissioning, HMSS

SUBJECT:

SALT LAKE CITY / CLIVE TEM SUPPLEMENT As requested, we have performed a review of the proposed Modification No. I to the remedial actions at the Salt Lake City / Clive site and have prepared a supplement to the original 1985 technical evaluation memorandum (TEM). The supplement is attached to this memo.

This supplement addresses the geotechnical (slope stability and radon emanation) aspects of the proposed modification to the RAP. Our review of the information provided by the DOE indicates that the geotechnical aspects of the proposed changes are acceptable, and we conclude that the proposed design will continue to meet the long-term stability and radon emanation requirements of 40 CFR Part 192.

This TEM supplement was prepared by Banad Jagannath; please contact him should you have any questions on this.

Michael Tokar, Section Leader Technical Branch Division of Low-Level Waste Management and Decommissioning, HMSS

Enclosure:

As stated ,

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IL SUPLMT TO TEM, SLC/ RAP MOD /BJ SUPPLEMENT TO TECHNICAL-EVALUATION MEMORANDUM SALT LAKE CITY /CLIVE REMEDIAL ACTION PLAN Prepared by: Banad Jagannath, LLTB, LLWMD.

Documents Reviewed (

References:

1. Attachment 1, Modification to che Remedial Ac'. ion Plan and Site Conceptual Design for Stabilization of the Inactive Uranit.m Mill Tailings Site at Salt Lake City, Utah, Revised Final, April 1988.

2. Letter dated May 19, 1988, from W. J. Arthur of DOE to P. Lohaus of HRC; submitting revised page to Modification No. 1 of the Salt Lake City, Utah, Final Remedial Action Plan.

Background

In our previous technical evaluation memorandum, which was completed in 1985, evaluations of the geotechnical engineering aspects of the design were presented. In that document, the staff concluded that the remedial action design, as proposed, would meet the long-term stability and radon emanation requirements of 40 CFR Part 192.

DOE now proposes to revise that original design by increasing the size of the remediated pile in order to accommodate approximately 250,000 cubic yards of additional contaminated material resulting from remedial action at the Vitro site and at vicinity properties. DOE proposes to extend the tailings embankment at the Clive disposal site approximately 400 feet to the south (Reference 1). This change increases the area of the pile, but the slope geometry and the radon barrier details are identical to those in the RAP design concurred by the NRC in 1985.

-Discussion The DOE provided information documents the changes that have been proposed for the configuration of the original tailings embankment. The items of geotechnical engineering concern are stability of the slopes and the radon

. barrier design.

1. Slope Stability The geometry (height and slope) of the proposed extension to the embankment is similar to that under construction, which is as per the final RAP design

O a

' SUPLMT TO TEM, SLC/ RAP MOD /BJ that was concurred in by the NRC. Our review of the geotechnical data submitted with the final RAP indicates that the foundation conditions at this extension are similar to those under the already completed tailings embankment.

The engineering properties of the vicinity property material designated to be stabilized in this extension are expected to be similar to those used for the tailings in the stability evaluation of the tailings embankment that was concurred in by the NRC. Since the work is performed under the same contract, it is expected that the construction specifications will be same as those in the final RAP. We expect the geotechnical stability aspects of the proposed

- modification to be similar to that final RAP design, and therefore, do not

- require a repeat evaluation. We concur with the DOE's conclusion on the geotechnical stability aspects of the proposed Modification No. 1 to the final RAP.

2. Radon Barrier The.Ra-226 concentration of the additional contaminated material is estimated to be equal to that of the residual radioactive material already placed in the tailings embankment at the Clive site (Reference 2). The radon barrier material and its layer thickness are unchanged from those in the original design in the RAP. Since the work is performed under the same contract, it is expected that the construction specifications will be same as those in the final RAP. As there is no change in the values of the parameters used in the design of the radon barrier, there is no need for a repeat design of the radon barrier. The radon barrier constructed as per the design concurred in at the final RAP stage is expected to satisfy the radon emanation requirements of 40 CFR Part 192. We concur with the DOE's conclusion on the radon emanation aspects of the proposed Modification No 1 to the final RAP.

3. Conclusions Based on review of the information provided, we conclude that the proposed design for disposing additional contaminated material at the Clive site will meet the icng-term performance objectives and radon emanation standards of 40 CFR Part 192.

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