ML19189A233

Letter to A.Denny NRC Staff Review of Reduction in Compaction of the Radon Cover at Mexican Hat Utah Umtrca Title 1 Site

ML19189A233
Person / Time
Site:	WM-00063
Issue date:	07/15/2019
From:	Dennise Orlando Division of Decommissioning, Uranium Recovery and Waste Programs
To:	Denny A US Dept of Energy, Office of Legacy Management
Orlando D
References
Download: ML19189A233 (3)

Text

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 15, 2019 Ms. Angelita Denny, Site Manager U.S. Department of Energy Office of Legacy Management 2597 Legacy Way Grand Junction, CO 81503

SUBJECT:

INTERIM COVER PROTECTION COMPACTION VARIANCE AT THE U.S.

DEPARTMENT OF ENERGYS MEXICAN HAT, UTAH, URANIUM MILL TAILINGS RADIATION CONTROL ACT SITE (Docket Number WM-00063)

Dear Ms. Denny:

I am writing in response to the U.S. Department of Energy (DOE) letter and supporting information, dated June 26, 2019, in which you discuss the rationale for the reduced compaction for the radon barrier at the Mexican Hat, Utah, Uranium Mill Tailings Radiation Control Act (UMTRCA) site from 100 percent (100%) of the standard proctor to 95% of the standard proctor (Agencywide Documents Access and Management System [ADAMS] Accession Number ML19183A183). This action is related to ongoing maintenance of the site due to the identification of depressions on the cell cover and the DOE actions to identify the cause, and address, the depressions.

In your letter you explain that the area on the radon barrier is much smaller than the original area of the radon barrier, that the shape of the area being addressed by the maintenance is irregular in shape and that the equipment available to perform the compaction within the work area limits the ability to achieve100% compaction. You also provide a discussion that it is possible to achieve the hydraulic conductivity of the original radon cover with 95% compaction.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed DOEs explanation for compaction of the radon barrier to 95 percent of the standard proctor value and agrees that the overall hydraulic conductivity goal for the radon barrier can be reached at a lower compaction value. Additionally, the NRC staff recognizes that the limited work area will necessitate the use of smaller construction equipment. Use of small construction equipment will make it more challenging to reach 100 percent compaction. For these reasons, the NRC staff has no comments on DOEs plans to conduct the maintenance/repair at the Mexican Hat site at this time. We would expect that, once the maintenance of the site is completed, DOE will perform radon flux measurements to ensure that the cover meets the requirements in 10 Code of Federal Regulations Part 40, Appendix A.

A. Denny In accordance with 10 CFR 2.390 of the NRCs Agency Rules of Practice and Procedure, a copy of this letter will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of NRCs ADAMS. ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html.

If you have any questions concerning the NRC comments please feel free to contact me at 301-415-6749 or at Dominick.Orlando@nrc.gov.

Sincerely,

//RA//

Dominick Orlando, Senior Project Manager Uranium Recovery and Materials Decommissioning Branch Division of Decommissioning, Uranium Recovery and Waste Programs Office of Nuclear Material Safety and Safeguards Docket No. WM-00063

A. Denny

SUBJECT:

INTERIM COVER PROTECTION COMPACTION VARIANCE AT THE U.S.

DEPARTMENT OF ENERGY S MEXICAN HAT, UTAH, URANIUM MILL TAILINGS RADIATION CONTROL ACT SITE (Docket Number WM-00063)

DATE: July 15, 2019 DISTRIBUTION:

REvans RIV HGepford, RIV ADAMS Accession Number ML19189A233 *via e-mail OFFICE NMSS NMSS NMSS NMSS NMSS NAME NOrlando SAchten DMandeville RvonTill NOrlando DATE 7/8/19 7/8/19 7/9/19 7/12/2019 7/15/19 OFFICIAL RECORD COPY