ML20087H981

Environmental Properties Management, LLC - Cimarron Environmental Response Trust, Report on the Evaluation of Reducing Conditions in Burial Area 1

ML20087H981
Person / Time
Site:	07000925
Issue date:	03/25/2020
From:	Lux J Environmental Properties Management
To:	Davis P, Robert Evans, Kenneth Kalman Document Control Desk, Office of Nuclear Material Safety and Safeguards, NRC Region 4, State of OK, Dept of Environmental Quality (DEQ)
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ML20087L249	List: ML20087H981
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Download: ML20087H981 (2)

Text

March 25, 2020 Mr. Ken Kalman U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738 Mr. Paul Davis Oklahoma Department of Environmental Quality 707 North Robinson Oklahoma City, OK 73101 Mr. Robert Evans U.S. Nuclear Regulatory Commission 1600 East Lamar Blvd; Suite 400 Arlington, TX 76011-4511 Re: Docket No.70-925; License No. SNM-928 Cimarron Environmental Response Trust Report on the Evaluation of Reducing Conditions in Burial Area #1

Dear Sirs:

Solely as Trustee for the Cimarron Environmental Response Trust (CERT), Environmental Properties Management LLC (EPM) submits herein to the US Nuclear Regulatory Commission (NRC) and the Oklahoma Department of Environmental Quality (DEQ) a report on the evaluation of reducing conditions in groundwater in Burial Area #1 (BA1) of the Cimarron site.

A remediation pilot test was conducted during the 4th Quarter of 2017 and the 1st Quarter of 2018. This pilot test included the installation of one groundwater extraction trench and several treated water injection trenches. The purpose of the pilot test was to reduce uncertainties associated with planned rates of extraction and treated water re-injection associated with trenches constructed in the fractured sandstone formations and transition zone deposits present at the site.

Construction of Groundwater Extraction Trench GETR-BA1-01 began on October 17, 2019 and was completed on November 3, 2017. Because the trench was excavated in unconsolidated soils, an organic biopolymer slurry was introduced to the trench during excavation to prevent collapse of the trench sidewalls. As the extraction trench was backfilled with gravel, the slurry that was displaced by the backfilling process was transferred to frac tanks while a positive head differential was maintained between the elevation of the slurry and the surrounding groundwater elevation.

Shortly after completing the pilot test on November 27, 2017, samples were collected from 12 monitor wells located in BA1. These samples were analyzed for uranium, and sample results were compared with data from the 3rd Quarter of 2017 sampling event, conducted from August 1 through 3, 2017. Comparison of the Q3 2017 analytical results with the December 4, 2017 sampling data indicated there was an apparent significant decrease in the concentration of uranium in several monitor wells down gradient of the GETR-BA1-01 Trench Analytical results from samples collected during the next quarterly groundwater sampling event appeared to show a continuing trend of decline in uranium concentrations in monitor wells located near and downgradient from the GETR-BA1-01 Trench.

Subsequent measurement of dissolved oxygen (DO) and ox-redox potential (ORP) indicated that reducing conditions had been created in groundwater surrounding the trench. This initiated an evaluation of the oxidation-reduction characteristics of the groundwater in and around GETR-BA1-01.

The enclosed Burial Area #1 Redox Evaluation Report describes the work performed in BA1, presents the data obtained, and provides the results of an evaluation of the data and conclusion regarding the impact of the biopolymer slurry on BA1 redox conditions and uranium groundwater concentrations. The anticipated trends in redox conditions and uranium concentrations (i.e., rebound in aquifer redox potential and uranium concentrations in groundwater) are also discussed. Finally, the report presents a plan for continued groundwater monitoring and discusses how this impacts the design, construction, and operation of groundwater remediation components during full-scale remediation activities.

If you have questions or comments, please contact me at 405-641-5152 or at jlux@envpm.com or John Hesemann at 816-822-3369 or at jhesemann@burnsmcd.com.

Sincerely, Jeff Lux, P.E.

Trustee Project Manager Enclosure cc: NRC Public Document Room (electronic copy only)