ML22084A593
| 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 | |
| Shared Package | |
| ML22084A590 | List: |
| References | |
| Download: ML22084A593 (1) | |
Text
Revised Conceptual Site Model Source: Figure 2A, Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.
Cross section lines from 2006 Revised Conceptual Site Model. Section Line A-A is along the approximate centerline of the uranium plume.
Revised Conceptual Site Model Source: Figure 4, Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.
- Black line - escarpment at groundwater surface
- Magenta - SSB surface
- Tan - interconnected, permeable sand channel deposits
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 Source: Figures 5, 6, and 7, Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, ML18100A297.
- Tan - interconnected, permeable sand channel deposits
- Green - Upper Gully Fill deposits
- Blue - Lower Gully Fill deposits
Remediation Design This figure was generated for internal use only and was not incorporated into a report.
- Gray - extent of interconnected, permeable sand channel deposits
- Red dashed lines -
groundwater extraction trenches
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 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".
- 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.
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.
- Treated water will be injected during full-scale remediation; injection-enhanced conditions are not reflected in the extraction rate used in timeframe calculations.