ML22084A593

Burns and Mcdonnell Remediation Slides Presented 2022-03-10

ML22084A593
Person / Time
Site:	07000925
Issue date:	03/25/2022
From:	Lux J Environmental Properties Management
To:	Jennifer Davis, Robert Evans, James Smith NRC/NMSS/DDUWP/URMDB, State of OK, Dept of Environmental Quality (DEQ)
Smith J
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ML22084A590	List: ML22084A592 ML22084A593
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Download: ML22084A593 (1)

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Revised Conceptual Site Model Cross section lines from 2006 Revised Source: Figure 2A, Environmental Conceptual Site Model. Section Line Sequence Stratigraphy (ESS) and A-A is along the approximate Porosity Analysis, Burial Area 1, ML18100A297.

centerline of the uranium plume.

Revised Conceptual Site Model

• Black line - escarpment at groundwater surface

• Magenta - SSB surface

• Tan - interconnected, permeable sand channel deposits Source: Figure 4, Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.

Revised Conceptual Site Model This image was not taken from a report. It was generated from the same EVS model to provide a different view.

Revised Conceptual Site Model

• Tan - interconnected, permeable sand channel deposits

• Green - Upper Gully Fill deposits

• Blue - Lower Gully Fill deposits Source: Figures 5, 6, and 7, Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.

Remediation Design

• Gray - extent of interconnected, permeable sand channel deposits

• Red dashed lines -

groundwater extraction trenches This figure was generated for internal use only and was not incorporated into a report.

BA1 Transition Zone Remediation Plan

• Light green - groundwater extraction trenches

• Light blue - treated water injection trenches Source: Figure 8-2(b), Facility Decommissioning Plan - Rev 2, ML21076A479

Distribution of Uranium in BA1

• Uranium is not evenly distributed within BA1 aquifer sediments

• Based on results for 204 soil samples collected from 21 borings completed in the BA1 Transition Zone, uranium in BA1 primarily resides within permeable sand channel deposits

• 45 samples collected from 10 borings exhibited U > 7 pCi/g (background)

• Of those 45, only 8 were collected from low permeability material

Distribution of Uranium in BA1

• Maximum background =

7 pCi/g uranium

• 159 samples

< 7 pCi/g uranium This chart was generated for internal use only and was not incorporated into a report.

Note: two of the three samples in the two highest concentration categories were collected from mixed sand/clay zones and the third sample was collected at the base of a sand zone in "shale".

Distribution of Uranium in BA1

• The BA1 permeable sand channel deposits represent approx. 16% of the total transmissive pore volume; however, 100% of the saturated pore volume was used to estimated the remediation time requirement.

Source: Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.

Note: Sand channel deposits represent 9% of the bulk aquifer volume and 16% of the transmissive pore volume.

BA1 Remediation Duration Projection

• The linear sorption model* used to estimate timeframe

• Key inputs:

• Retardation parameters (density, porosity, Kd)

• Saturated pore volume (3D TZ/SSB body bounded by MCL, capture zone, TZ/Alluvium interface)

• Co - highest U conc. in any well

• Cf - DCGL

• Projected extraction rate (derived from GETR-BA1-01 pump test)

• Other than determining the injection/extraction capture zone, the numerical groundwater model was not used in estimating remediation timeframe.

Source: Attachment 9.1, Basis of Design for Groundwater Remediation, Appendix K to Facility Decommissioning Plan - Rev 2, ML21076A479.

BA1 Remediation Duration Projection

• Assumptions & Limitations

• The estimated number of pore volume (PV) exchanges required to achieve 180 pCi/L assumes linear, reversible and instantaneous desorption.

• Each PV was assumed to be replaced with water containing no uranium.

• Treated water will be injected during full-scale remediation; injection-enhanced conditions are not reflected in the extraction rate used in timeframe calculations.

• Uranium is believed to present in only 16% of the PV; however, 100% of the PV was used in the timeframe calculation. The PV containing the uranium is the PV that will yield groundwater to extraction and transmit injected water.