ML22308A076

Burns & Mcdonnell, Basis of Design for Groundwater Remediation

ML22308A076
Person / Time
Site:	07000925
Issue date:	10/07/2022
From:	Hesemann J Burns & McDonnell
To:	Lux J Office of Nuclear Material Safety and Safeguards, Document Control Desk
Shared Package
ML22308A152	List: ML22299A119 ML22307A296 ML22307A307 ML22307A316 ML22308A076
References
BMCD-GWREMED-TM007, Rev A
Download: ML22308A076 (1)

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Memorandum BURNS MSDONNELL Document No.: BMCD-GWREMED-TM007 Revision: A Date: October 7, 2022 To: Jeff Lux, EPM From: John Hesemann, Bums & McDonnell Emily Pulcher, Bums & McDonnell

Subject:

Basis of Designfor Groundwater Remediation This Basis of Design (BOD) for Groundwater Remediation has been developed to support remediation design activities and preparation of the Facility Decommissioning Plan Revision 3 (D-Plan) for the Cimarron Environmental Response Trust (CERT) remediation project at the Cimarron Site located in Guthrie, Oklahoma (Site).

The initial development of a groundwater remediation system design to support the initial D-Plan submitted in 2015 included groundwater extraction, treatment, and injection infrastructure required to facilitate remediation of uranium and nitrate exceeding their respective Maximum Contamination Levels (MCLs). The first revision of the D-Plan, submitted in 2015, included an evaluation of Technetium-99 (Tc-99) concentrations in groundwater recovered by the remediation system. This evaluation resulted in modifications to treatment waste disposal criteria and costs, leading to a determination that available funding was not sufficient to support nitrate treatment. The design and D-Plan were revised a second time to develop a phased approach to groundwater remediation that contemplated the addition of remediation and treatment infrastructure, provided adequate funding would be available, as groundwater criteria across the Site were achieved. However, this revision did not provide a clear path to achieving remedial objectives. The remediation system design and D-Plan have subsequently been revised a third time, to provide a clear path to achieving the primary goal for the Site - to reduce uranium concentrations below the Nuclear Regulatory Commission (NRC) criteria, for unrestricted release of the Site. While uranium is the only contaminant exceeding these criteria, this BOD includes other select contaminants (such as nitrate and Tc-99, as detailed above) associated with former operations at the Site that may impact water treatment technologies and/or discharge considerations. Hereafter, the NRC criterion for uranium is referred to as the Derived Concentration Goal Level (DCGL).

The efficacy of the groundwater remediation technologies proposed for implementation at the Site (groundwater extraction and injection) have been demonstrated through previous investigative activities (e.g., pump testing, packer testing, site investigation, groundwater modeling, etc.) as well as pilot testing conducted in late 2017 and early 2018. Likewise, the efficacy of the technology proposed for treatment of recovered groundwater at the Site (ion

Memorandum (contd) BURNS ^ISDONNELL October 7, 2022 Page 2 of21 exchange) was demonstrated through treatability testing conducted in 2015. Results of the treatability testing demonstrated that ion exchange is capable of reducing the concentration of uranium in groundwater recovered at the Site to below the permissible discharge concentration of 30 micrograms per liter (pg/L).

The processes used to develop the remediation basis of design are summarized in the following sections.

1.0 Uranium Groundwater Data Review Laboratory analytical results for samples collected from select monitor wells from 2011 through 2017 were used to establish representative groundwater concentrations to support detailed design, pilot testing, D-Plan development, etc. (see Section 3.0 below). A review of these results was performed in accordance with the United States Environmental Protection Agencys National Functional Guidelines for Inorganics Superfund Methods Data Review (National Functional Guidelines for Inorganics)12. The review was performed to assess the validity of the laboratory data, including uranium mass concentrations used in calculating representative groundwater concentrations to support design basis development (see Section 3.0 below). No uranium mass concentration data were rejected as a result of the analytical data review. The uranium concentration data are included as Attachment 1.

2.0 Tc-99 Groundwater Data Review In 2019, additional sampling was conducted to assess the nature and extent of Tc-99 in groundwater and to estimate potential concentrations recovered from the proposed groundwater extraction network. A review of the laboratory analytical results was performed in accordance with the National Functional Guidelines for Inorganics to assess the validity of the laboratory data. Tc-99 activity concentration data were rejected as a result of the analytical data review for the following WA monitor wells: T-79, 1348, 1395, 1396, 1337, and 1319B-2. Tc-99 activity concentration data were rejected for the following BA1 monitor wells: 1314, TMW-08, 02W06, 02W44, TMW-13, and TMW-24. The Tc-99 activity concentration result was also rejected for the surface water sample 1201 (Upstream). The primary cause for the rejection of Tc-99 activity concentration data was a negative activity concentration result; Tc-99 concentrations cannot be 1 Kurion, Inc. (2015). Cimarron Environmental Response Trust, 2015 Groundwater Treatability Tests (KUR-ENVI01-001-RPT-002 Rev. 0). Richland: Barker, Luey, Gholami, Mertz, Walton.

2 United States Environmental Protection Agency. (2017). National Functional Guidelines for Inorganics Superfund Methods Data Review (EPA-540-R-201 7-001). Office of Superfund Remediation and Technology Innovation. Washington, DC.

Memorandum (contd) burn s ; msdon nell October 7, 2022 Page 3 of21 negative. All rejected data were qualified as not detected above the minimum detectable concentration (MDC). The Tc-99 activity concentration data are included in Attachment 1.

The Tc-99 activity concentrations were converted to mass concentrations using specific activity.

The specific activity of Tc-99 is 0.017 curies per gram (Ci/g), equivalent to 0.059 nanograms per picocurie (ng/pCi).

3.0 Calculation of Representative Groundwater Concentrations Representative groundwater concentrations were calculated for the Site in accordance with the following process:

3.1 Monitor wells for which data are available for years 2011 through Second Quarter (Q2) 2017, located within and in the vicinity of remediation areas, and screened within the appropriate aquifer units, were selected for use in design basis development.

Groundwater data associated with these wells were transferred from the project database into an MS Excel data workbook. Uranium, nitrate, and fluoride data sheets exported from the MS Excel data workbook are included as Attachment 1.

If multiple concentrations were reported for a given monitor well in a single sampling event (e.g., a sample and a duplicate), the highest of the available concentrations for a given monitor well within the same event were used.

3.2 For monitor wells with at least four independent sample results, data from the worksheets identified in Attachment 1 were imported into the ProUCL Ver. 5.1002 software application for calculation of the ninety-five percent upper confidence level of the arithmetic mean (95% UCL) concentration. The software application calculated the uranium, nitrate, and fluoride 95% UCL data concentrations.

If the 95% UCL value recommended by ProUCL exceeded the maximum observed value for a given monitor well, the maximum observed value was used in place of the 95% UCL. The 95% UCL values calculated by the software application assumed normal distribution using the 95% Students-t UCL. This methodology was employed due to the small sample size and relatively varied concentrations at some monitor wells. ProUCL provides suggested UCL determination methods based on the characteristics of the data set. The Students-t UCL method was suggested for the majority of the data sets, and for instances in which the data set did not exhibit a normal distribution and the Students-t method was not suggested, ProUCL was unable to recommend an alternative method, based on data set characteristics and methods available within the program. In addition, tests conducted using other statistical methods provided concentration results that were comparable to those calculated using the Students-t method. Based on these factors, the Students-t determination method was used to calculate the 95% UCL contaminant concentration for all applicable data sets.

Memorandum (contd) BURNS ^M£DONNELL October 7, 2022 Page 4 of 21 The 95% UCL concentrations calculated by ProUCL for uranium, nitrate, and fluoride are tabulated in Attachment 1.

3.3 For each monitor well, the representative groundwater concentrations used in basis of design development consisted of:

• The 95% UCL concentration (if calculated);

• The maximum contaminant concentration (if used in place of the 95% UCL value);

or,

• The average contaminant concentration (if data were not sufficient to determine the 95% UCL concentration).

These representative uranium, nitrate, and fluoride concentrations were added to the data sheets included as Attachment 1, in the column labeled Representative Groundwater Concentration.

3.4 Representative uranium groundwater concentrations were evaluated in 2019 during the first revision of the D-Plan to incorporate additional groundwater concentration data generated from Q3 2017 through Q4 2018. The updated representative uranium groundwater concentrations were compared to the previous representative concentrations to determine if concentrations increased or decreased. The updated representative uranium concentrations associated with monitor wells in each remediation area were also evaluated to determine if the concentration data caused an appreciable increase in any of the following for each remediation area: the uranium groundwater plume area or pore volume, initial treatment system influent uranium concentration, and/or maximum uranium groundwater concentration. The representative uranium groundwater concentration did increase for several individual monitor wells; however, there were no appreciable increases to the values listed above. Therefore, the original representative uranium groundwater concentrations calculated using data from 2011 to Q2 2017 were considered appropriate for use in the updated D-Plan.

3.5 The 2019 Tc-99 groundwater analytical results are considered representative concentrations for the purposes of the isopleth map generation and influent concentration estimates described in the following sections. The historical Tc-99 groundwater dataset was not used in this evaluation due to issues related to the quality, quantity, and distribution of the data.

4.0 Isopleth Map Generation The representative groundwater concentrations were used to generate isopleth maps for the Site.

Representative groundwater concentrations for each monitor well and contaminant, and northing and easting coordinates for each monitor well were transferred into an input data file that was subsequently imported into the Surfer software application developed by Golden Software.

Memorandum (contd) BURNS ^MSDONNELL October 7, 2022 Page 5 of 21 Surfer was used to generate isopleth concentration plots for both Burial Area 1 (BA1) and the Western Area (WA).

For BA1, representative uranium groundwater concentrations for wells screened within the Sandstone B (SSB), transition zone (TZ), and alluvium formations were combined to develop a uranium isopleth map.

For the WA, representative uranium, Tc-99, nitrate, and fluoride groundwater concentrations for wells screened within SSB, TZ, and alluvium formations were combined to develop isopleth maps for each contaminant. In addition, representative uranium, Tc-99, nitrate, and fluoride groundwater concentrations for wells screened within Sandstone A (SSA) were used to develop separate isopleth maps for each contaminant. Copies of the BA1 and WA isopleth maps are included as Attachment 2.

The isopleth maps described above provided a refined understanding of contaminant nature and extent. This served as the basis for assessing groundwater injection and extraction component quantities and locations. Each remediation area was reviewed to determine the location of remediation components to maximize contaminant capture, mass removal, and overall performance.

5.0 Groundwater Modeling and Remediation Simulations A groundwater model was developed for both the BA1 and WA to support the evaluation of groundwater remediation alternatives and subsequent remediation design. The groundwater model generation, review, and calibrations are documented in the Groundwater Flow Model Report Cimarron Remediation Site.3 Once remediation component quantities, locations, and dimensions of proposed groundwater extraction and injection infrastructure were established, a comprehensive review of geospatial coordinate data and data acquisition protocols was conducted to confirm proper control of coordinate data and the consistent use of current coordinate data by all design applications (e.g.,

ArcGIS, AutoCAD, Surfer, EVS, MODPATH/MODFLOW). This review confirmed that consistent geospatial coordinate data were utilized by all applications during the ongoing design efforts. This review was documented in a memorandum entitled CERT Groundwater 3Burns & McDonnell Engineering Company. Groundwater Flow Model Report Cimarron Remediation Site. October 2022. Kansas City, Missouri.

Memorandum (contd) BURNS MSDONNELL October 7, 2022 Page 6 of 21 Remediation Project - Review of Geospatial Coordinate Systems and Data Management Practices,4.

Groundwater flow models were revised multiple times based on information obtained from additional groundwater assessment, pilot testing, remedial objectives, and comments received from the NRC. The groundwater flow model results were used to determine target flow rates for individual extraction and injection components. The groundwater model was used to perform particle tracking analyses and generate capture zone depictions for remediation components located in alluvial areas. Iterative remediation simulations (particle tracking model runs) were then performed to confirm adequate capture of injected water and groundwater contamination exceeding remediation criteria. The criteria used in this evaluation are as follows:

• Extraction components in both the WA and BA1 remediation areas must achieve capture of uranium contamination exceeding the DCGL.

• Extraction components in the BA1 and 1206-NORTH areas must achieve capture of injected water.

o At a minimum, the total recovery rate for extraction components located downgradient of injection components must equal the total injection rate for those injection components.

o The capture zone of extraction components must encompass the zone of injection influence.

Results of the particle tracking analyses, including finalized remediation component locations and capture zones, are depicted in figures included as Attachment 3.

Pilot test results (discussed below in Section 6.0) for trenches installed within the transition zone and sandstone formations were determined to be more reflective of actual conditions than those predicted by the model; consequently, numerical groundwater modeling was not used for these areas. Instead, potentiometric surface contours, pumping test drawdown analyses, and dye tracer test results were used to optimize designs for remediation components proposed for construction in these formations.

Final nominal combined flow rates for the BA1 and WA remediation systems are 100 and 107 gpm, respectively. Determination of these flow rates was based on numerous factors including4 4Burns & McDonnell Engineering Company. CERT Groundwater Remediation Project - Review of Geospatial Coordinate Systems and Data Management Practices. August 24, 2018. Kansas City, Missouri.

Memorandum (contd) BURNS MCDONNELL October 7, 2022 Page 7 of 21 contaminant distribution, aquifer characteristics, groundwater modeling, pilot testing, remedial objectives, and NRC comments.

Nominal treated water infiltration rates used to estimate remediation timeframes for remediation areas are as follows:

Nominal Infiltration Rate Remediation Area (gpm)

BA1-A 28 WU-BA3 8 Nominal groundwater extraction rates used to estimate remediation timeframes for remediation areas are as follows:

Nominal Extraction Rate Remediation Area (gpm)

BA1-A 14 BA1-B 86 WAA U>DCGL 99 1206-NORTH 8 Notable updates resulting from pilot testing activities are described below.

6.0 Design Revisions Resulting from Pilot Testing A pilot test consisting of injection and extraction trench construction, injection pilot testing, and extraction pump testing, began in the Fourth Quarter (Q4) of 2017 and was completed in the First Quarter (Ql) of 2018. Pilot test results were used to refine the location of remediation components to maximize contaminant capture, mass removal, and optimize the overall design.

Results were also used to revise anticipated recovery rates for the following remediation components.

BA1 injection and extraction component quantities, locations, dimensions, and design parameters were updated to maximize contaminant mass removal, minimize remediation duration, and optimize the overall design. Updates included the following:

• The anticipated groundwater recovery rate for extraction trench GETR-BA1-01 is 7 gallons per minute (gpm) based on pumping test results.

• Extraction trench GETR-BA1-02 was relocated and the anticipated groundwater recovery rate is 7 gpm. The position and length of this trench were also refined based on a detailed review of the lithology within this zone. The results of this review are detailed in

Memorandum (coatd) BURNS MCDONNELL October 7, 2022 Page 8 of 21 Environmental Sequence Stratigraphy and Porosity Analysis, conducted by Burns &

McDonnell in April 20185.

• The anticipated water infiltration rate for injection trench GWI-BA1-01 is 10 gpm based on water injection test results.

• Injection trench GWI-BA1-02 was reconfigured and a third injection trench (GWI-BA1-

03) was added. The anticipated water infiltration rate for each of these trenches (GWI-BA1-02 and GWI-BA1-03) is approximately 4 gpm.

Additional details regarding these design modifications were presented in the Remediation Pilot Test Report, prepared by Burns & McDonnell in June 20186. The final locations and dimensions of the remediation components described above are presented on the figure included as and in Figure 8-2 of the D-Plan.

WA injection and extraction component quantities, locations, dimensions, and design parameters were updated to maximize contaminant mass removal, minimize remediation duration, and optimize the overall design. Updates included the following:

• The anticipated water infiltration rate for injection trench GWI-WU-01, located in WU Burial Area 3 (WU-BA3), was revised based on the results of water injection pilot tests conducted at WU-UP1. The WU-UP1 pilot test injection trenches are located approximately 600 feet from GWI-WU-01 and are constructed in the same formation (SSA) as GWI-WU-01.

• The anticipated groundwater extraction rate for extraction trench GETR-WU-01, proposed for construction within TZ deposits in the 1206-NORTH remediation area, was revised based on the results of the groundwater pumping test conducted at GETR-BA1-01, the extraction trench constructed within BA1 TZ deposits.

Additional details regarding these design modifications were presented in the Remediation Pilot Test Report. The final locations and dimensions of the remediation components described above are presented on the figure included as Attachment 5 and in Figure 8-1 of the D-Plan.

5 Bums & McDonnell Engineering Company. (2018). Environmental Sequence Stratigraphy (ESS) and Porosity Analysis, Burial Area 1, Cimarron Former Nuclear Fuel Production Facility.

Concord: Mike Shultz.

6 Burns & McDonnell Engineering Company. (2018). Remediation Pilot Test Report. Kansas City.

Memorandum (contd) BURNS i^lMSDONNELL October 7, 2022 Page 9 of 21 7.0 Remediation Area and Pore Volume Estimates Pore volume, calculated by multiplying the aquifer volume targeted for remediation by effective porosity, is one of the input parameters required to calculate the remediation timeframe required to achieve remediation goals. The input values selected for the remediation area and pore volume calculations are summarized below.

7.1 Porosity Based on the results of previous site investigations, Environmental Properties Management LLC (EPM) and Burns & McDonnell concluded that the porosity used in the remediation duration estimates should be the effective porosity rather than the total porosity. Previous investigations have indicated that most contaminant mass requiring remediation, particularly in the less permeable TZ and weathered/fractured sandstone formations, resides within the interconnected pore space of the aquifer. Since the groundwater extraction/injection remedies will also affect contaminant removal and transport within the interconnected pore space, effective porosity is the most appropriate input parameter for estimating remediation timeframes.

Geotechnical data generated by Standard Testing in 2015 indicated that the total porosity for soils collected in the UP1 area varied from 0.34 to 0.46 in the six soil samples collected during the 2014 design investigation. As with density, the soils submitted for porosity analyses are considered representative of TZ and weathered bedrock formations.

Effective porosity values were developed for sandstone and alluvial soils based on: a) a lack of analytically-derived effective porosity values, b) a minimum total porosity of 0.34, and c) characteristics of the materials comprising the water-bearing units at the Site.

The effective porosity of TZ soils was based on the findings of the ESS Report5.

In summary, the effective porosity values used in calculations associated with the remediation duration estimates are as follows:

Remediation Area Formation / Soil Type Effective Porosity TZ/

BA1-A 0.11 SSB (weathered/fractured)

BA1-B WAA U>DCGL Alluvium 0.30 WU-BA3 1206-NORTH TZ 0.11 7.2 The lateral extent of each remediation area was estimated based on:

• The approximate hydraulic capture zone of extraction component(s) exhibiting uranium concentrations at or above 30 pg/L; and/or

Memorandum (cantd) BURNS MCDONNELL October 7, 2022 Page 10 of 21

• The approximate hydraulic zone of influence associated with injection component(s).

The formation specific uranium isopleth maps generated for BA1 and the WA (see Section 4.0), and particle tracking depictions generated during remediation simulation analysis (see Section 5.0) were used to estimate the lateral extent of each remediation area.

Two separate remediation areas, one for uranium and another for nitrate/Tc-99, were estimated for the WAA U>DCGL area based on the updated particle tracking analysis results discussed above. Although nitrate and Tc-99 are not target constituents for groundwater remediation, it is necessary to establish these remediation areas based on area of hydraulic influence to estimate water treatment system influent concentrations.

These influent concentrations are then used to evaluate compliance with treatment system effluent discharge limitations. The uranium WAA U>DCGL remediation area was estimated based on the extent of the hydraulic capture zone in which uranium concentrations are at or above the Oklahoma Department of Environmental Quality (DEQ) criterion (30 pg/T). The complete zone of WAA U>DCGL hydraulic capture was established as the nitrate/Tc-99 remediation area.

7.3 For most remediation areas, the targeted aquifer volume was calculated by multiplying the lateral extent of each remediation area by saturated thickness. Due to the variability in vertical formation thickness in the 1206-NORTH and BA1 TZ remediation areas, the aquifer volumes targeted for remediation in these areas were estimated using Earth Volumetric Studio (EVS), a three-dimensional visualization (3DV) application.

8.0 Area and Linear-Weigh ted Influent Concentration Estimates Area-weighted influent concentration estimates were performed to support remediation duration estimate calculations and the development of influent concentrations, as described in Sections 9.0 and 10.0, respectively. The contaminant and formation specific isopleth maps generated for BA1 and the WA (see Section 4.0), and particle tracking depictions generated during remediation simulation analysis (see Section 5.0) were used to perform incremental groundwater concentration averaging within the combined capture zone of each remediation area containing groundwater extraction components.

The isopleth maps were also used to conduct linear-weighted averaging for all three groundwater extraction trenches (GETR-BA1-01, GETR-BA1-02, and GETR-WU-01) to approximate initial influent uranium concentrations. Results of the area and linear-weighted averaging analysis completed for each applicable remediation area and groundwater extraction component are presented in Attachment 6. These calculation files in native (MS Excel) format can be provided to facilitate review of calculation methods (i.e., formulas, references, inputs, etc.) by NRC and DEQ personnel.

For the uranium remediation areas, the larger of the following was assumed as the initial concentration for estimating the required remediation duration: (1) the maximum representative

Memorandum (cont'd) BURNS: MSDONNELL October 7, 2022 Page 11 of 21 concentration reported for any well within the remediation area (determined using sampling results for monitoring events conducted from 2011 through the Q2 2017), (2) the concentration estimated by conducting incremental area-weighted averaging of concentrations within the specified treatment area.

The maximum representative uranium concentration reported for wells within the remediation areas are listed below:

Maximum Representative Remediation Area Uranium Concentration (Pg/L)

BA1-A 2,975 (TMW-09)

BA1-B 3,516 (TMW-13)

WAA U>DCGL 177.8 (T-62) 1206-NORTH 526.6 (MWWA-03)

WU-BA3 875 (1351)

Note: the monitor well associated with each result is identified in parentheses.

The area-weighted average concentrations used in calculations associated with remediation duration estimates are also summarized below:

Area-Weighted Average Remediation Area Uranium Concentration (Pg/L)

BA1-A 824 BA1-B 248 WAA U>DCGL 90.9 1206-NORTH 248 WU-BA3 311 For each remediation area, the maximum representative uranium concentration was greater than the area-weighted average uranium concentration.

9.0 Remediation Duration Estimates Remediation at the Site will require two separate but related functions - groundwater remediation and water treatment. The remediation function involves the extraction and injection of groundwater for the purposes of achieving groundwater remediation criteria. The water treatment function involves the removal of uranium from extracted groundwater to facilitate injection or discharge of the water. The duration of remediation varies by area and is generally determined by groundwater remediation criteria (DCGL) and injection and/or extraction flow rates. Operation of the BA1 and WA treatment systems must continue until uranium concentrations are below the MCL, thereby facilitating injection and/or discharge without

Memorandum (contd) BURNS MSDONNELL October 7, 2022 Page 12 of 21 treatment. Consequently, it may be possible for water treatment in either area to conclude before remediation (groundwater pumping and injection) is discontinued. Estimated remediation timeframes are discussed below and anticipated water treatment timeframes are discussed in Sections 9.0 and 10.0.

The estimated time required to achieve the remediation criterion in each remediation area and formation was calculated using the input parameters described below.

Density The results of geotechnical analyses performed by Standard Testing and Engineering Company (Standard Testing) on site-specific soils collected from the UP1 area in 2015 yielded bulk densities varying from 99.9 pounds per cubic foot (pcf) to 122.4 pcf, averaging 113 pcf (1.81 grams per milliliter [g/ml]). The soils submitted for these analyses are considered representative of TZ and weathered bedrock formations and the average density resulting from the analyses is considered appropriate for calculating remediation durations for alluvial areas as well.

Consequently, 1.81 g/ml was used as the bulk density for all remediation areas in calculations associated with the pore volume estimates. The use of the highest density results in the estimation of the greatest mass of sorbed contaminant, yielding longer duration estimates than if a lower density were used.

Distribution Coefficient (Kd)

Tests performed in 2002 and 2006 by Hazen and Associates reported uranium Kd values for various site-specific materials. The test demonstrated that uranium Kd increased as particle size decreased. Alluvial sand yielded a Kd of 0.5 milliliters per gram (ml/g), silt yielded a Kd of 2.0 ml/g, and clay yielded a Kd of 3.4 ml/g. All tests were conducted with groundwater from BA1; minor variations in groundwater geochemistry present across the site may impact Kd.

Consequently, more conservative values than those reported were in calculations associated with the remediation duration estimates.

None of the borings completed in TZ formations yielded only clay; they yielded of a mixture of clay, silt, and fine sand, and the use of a uranium Kd value of 3.4 ml/g for all TZ material was deemed overly conservative. Consequently, a value of 3.0 ml/g was selected for TZ soils.

Similarly, borings drilled in SSA and SSB contained a high degree of silt. Based on these observations, it was decided that a Kd lower than that reported for clay should be used for SSA and SSB. Consequently, a value of 3.0 ml/g was selected for SSA and SSB.

Clean sand yielded a uranium Kd of 0.5 ml/g during the Hazen tests. However, although borings in the floodplain do contain intervals of very clean sand, there is sufficient silt and/or clay to justify the use of a higher Kd value than that reported for clean sand. Consequently, a uranium Kd of 2.0 ml/g was used in Remediation Duration Estimates conducted for alluvial areas.

Remediation duration calculations were not needed for nitrate, since nitrate is not a target constituent for groundwater remediation; however, a Kd value was required to evaluate influent

Memorandum (cantd) BURNS ^M£DONNELL October 7, 2022 Page 13 of 21 nitrate concentrations over time as described below in Section 9.0. For nitrate, a Kd value of 0.6 ml/g was used for all formations and soil types. This value was deemed sufficiently conservative based on a review of applicable technical references.7,8 Kd values were not evaluated/selected for fluoride or Tc-99 since a concentration decay analysis was not required, as discussed below in Section 10.1.

In summary, the Kd values used in calculations associated with the remediation duration estimates and/or influent concentration analysis are as follows:

Uranium Kd Nitrate Kd Formation / Soil Type (ml/g) (ml/g)

TZ 3.0 0.6 SSA 3.0 0.6 SSB 3.0 0.6 Alluvium 2.0 0.6 Using comparatively high Kd values results in a greater total mass of uranium requiring removal, increasing the estimated duration of remediation.

A summary remediation and water treatment schedule is included as Attachment 7 and as Figure 9-3 of the D-Plan. The remediation duration estimate calculations and results for BA1 and the WA are presented in Attachments 8 and 9, respectively. A first-order kinetic sorption equation that assumes linear, reversible and instantaneous sorption was determined to be appropriate for modeling concentration decline and the time required to achieve remediation criteria in each area79. 8Remediation duration estimate calculation files in native (MS Excel) format can be provided to facilitate review of calculation methods (i.e., formulas, references, inputs, etc.) by NRC and DEQ personnel.

7 Krupka et al. (2004). Linearity and reversibility of iodide adsorption on sediments from Hanford, Washington under water saturated conditions. Water Research (Volume 38, Issue 8, April 2004, pp. 2009-2016). Elsevier.

8 Serne, R.J. Kd Values for Agricultural and Surface Soils for Use in Hanford Site Farm, Residential, and River Shoreline Scenarios (PNNL-16531). (2007). Washington: Pacific Northwest National Laboratory.

9 Fetter, C.W. (1993). Contaminant Hydrogeology (pp. 129-130). New York: Macmillan Publishing Company.

Memorandum (contd) BURNS MfDONNELL October 7, 2022 Page 14 of 21 9.1 BA1 was divided into two remediation areas (BA1-A and BAl-B) for the purpose of calculating duration estimates. BAl-A is defined as the area in which uranium exceeds the DCGL in SSB and the TZ. BAl-B is defined as the area in which uranium exceeds the DCGL in the alluvial material. BAl-A is expected to require more time to achieve the DCGL than any other remediation area at the Site; consequently, BAl-A is expected to drive the overall site remediation schedule. The BAl-A remediation timeframe is estimated to be 150 months. Groundwater extraction activities will continue in both BA1 remediation areas through 150 months to maintain the minimum required flow rate for treatment equipment.

9.2 Uranium groundwater concentrations exceed the DCGL in three WA remediation areas -

1206-NORTH (the drainage area in which uranium exceeds the DCGL), WAA U>DCGL (the area in which uranium exceeds the DCGL in alluvial material), and WU-BA3 (the area surrounding former Burial Area #3 in which uranium exceeds the DCGL);

consequently, the time required to achieve the DCGL for uranium was calculated for each of these areas. The 1206-NORTH remediation area is expected to achieve the DCGL after approximately 5 months. However, extraction will continue in 1206-NORTH until the WU-BA3 remediation area achieves the DCGL at approximately 48 months, to maintain downgradient capture of the treated water injected in WU-BA3. After 48 months, injection in WU-BA3 and extraction in 1206-NORTH will be discontinued. The WAA U>DCGL remediation area is expected to require the longest treatment timeframe of the WA remediation areas to achieve the DCGL for uranium, at 135 months. After 135 months, groundwater extraction activities will cease in the WA.

The remediation flow rates used in calculations associated with the remediation duration estimates consist of pumping rates and treated water infiltration rates associated with groundwater extraction and injection components, respectively, located within each remediation area.

10.0 Influent Contaminant Concentration and Treatment Duration Estimates The estimated concentrations of uranium, nitrate, Tc-99, and fluoride in BA1 and WA treatment system groundwater influents were calculated to support treatment system design and calculation of treatment system operational timeframes. The BA1 uranium treatment system and the WA uranium treatment system must operate until the uranium concentration in the combined influent falls below the MCL of 30 pg/L. An analysis was performed to estimate the time at which this will occur, and a separate analysis of nitrate effluent concentrations over time was conducted to confirm nitrate levels will not exceed the concentration anticipated to be acceptable to the DEQ

[30 milligrams per liter (mg/L)]. Since there will be no treatment of nitrate recovered with the extracted groundwater, the terms influent and effluent are used interchangeably when referring to nitrate water concentrations.

Memorandum (contd) BURNS MCDONNELL October 7, 2022 Page 15 of21 A detailed description of the processes used to estimate treatment system influent contaminant concentrations and operational timeframes is provided below and a summary remediation and water treatment schedule is included as Attachment 7.

10.1 Influent Concentrations Initial (i.e., time zero) and maximum (i.e., time t) influent contaminant concentrations were estimated for each groundwater extraction component. The initial and maximum contaminant concentrations were equivalent for all components and contaminants, except for nitrate and Tc-99 in three WAA U>DCGL wells. Nitrate and Tc-99 concentrations are expected to increase over time due to capture of groundwater with higher concentrations toward the edge of the capture zones for these wells. The initial and maximum influent contaminant concentrations for each extraction component were estimated using one of three methods:

• Concentration isopleth interpolation conducted using the Surfer software application;

• Linear-weighted concentration averaging (see Section 8.0);

• Area-weighted concentration averaging (see Section 8.0); or,

• Time-weighted concentration averaging (see below).

Since nitrate concentrations for individual WAA U>DCGL extraction wells are anticipated to increase over time (i.e., nitrate concentrations increase with distance east of the WAA U>DCGL extraction well alignment), a time-specific averaging approach was used to estimate influent nitrate concentrations for these wells. The time-specific concentrations were estimated by conducting incremental, area-weighted concentration averaging within the hydraulic capture zone of a given year. The entire WAA U>DCGL nitrate plume is anticipated to be captured within 5 years; therefore, time-specific concentration averaging was only performed for Years 1 through 5 (see Attachment 10).

The time-specific nitrate concentration estimates are considered conservative since the effects of dilution and dispersion are not accounted for in the analysis. As groundwater with elevated nitrate concentrations (located significant distances from the extraction wells) migrates toward the extraction wells, it will encounter and mix with groundwater with lower nitrate concentrations; however, the nitrate concentration estimated at the original plume location is assumed to persist over the entire groundwater capture flow path.

Influent nitrate concentrations were assumed to increase above the initial concentration for the following extraction wells:

• GE-WAA the estimated initial nitrate influent concentration for this well is 31 mg/L; however, the concentration is also expected to increase as higher concentrations, located to the east, are drawn toward the well. For the purposes of

Memorandum (cont'd) BURNS MCDONNELL October 7, 2022 Page 16 of 21 estimating WA Treatment Facility (WATF) influent concentrations, the influent nitrate concentration for this well is assumed to increase to approximately 47 mg/L, during Year 3 of operation, then decline thereafter (see Attachment 10).

• GE-WAA the estimated initial nitrate influent concentration for this well is 32 mg/L; however, the concentration is assumed to increase as groundwater with higher nitrate concentrations, located to the east, is drawn toward the well. For the purposes of estimating WATF influent concentrations, the influent nitrate concentration for this well is assumed to increase to a maximum of approximately 59 mg/L in Year 5 (see Attachment 10).

Initial influent fluoride concentrations were estimated using concentration isopleth interpolation conducted using the Surfer software application for wells and using linear-weighted concentration averaging (see Section 8.0) for trenches. These interpolated initial concentrations are assumed to be representative of the maximum influent fluoride concentrations, based on the location of the WA remediation components relative to the fluoride plume as depicted on Attachment 2. Fluoride is not present at detectable levels in the BA1 remediation areas.

The initial Tc-99 concentration for all remediation components is zero, since all components are located outside of the Tc-99 plume. However, a portion of the Tc-99 plume is within the estimated capture zones for extraction wells GE-WAA-02, GE-WAA-03, and GE-WAA-05. Therefore, the purpose of the Tc-99 concentration estimating process described in this paragraph is to estimate the maximum Tc-99 influent concentration that will occur sometime after groundwater extraction is initiated. These maximum influent Tc-99 concentrations were estimated using incremental area-weighted averaging of concentrations within the specified remediation areas as follows:

• GE-WAA the estimated area-weighted average Tc-99 concentration within the capture zone of this well is 2.67 nanograms per liter (ng/L).

• GE-WAA the estimated area-weighted average Tc-99 concentration within the capture zone of this well is 1.32 ng/L.

• GE-WAA the estimated area-weighted average Tc-99 concentration within the capture zone of this well is 0.92 ng/L.

Initial influent uranium concentrations were estimated using concentration isopleth interpolation conducted using the Surfer software application for wells, and using linear-weighted concentration averaging (see Section 8.0) for trenches. These interpolated initial concentrations are assumed to be representative of the maximum influent uranium concentrations, since the highest uranium concentrations are located along the WAA U>DCGL and BA1 extraction well alignments and trenches, as depicted on Attachment 2.

MemoraHdium (eontd) BURNS MSDONNELL October 7, 2022 Page 17 of 21 If a remediation area included more than one groundwater extraction component, flow rate-weighted averaging was used to calculate the estimated initial/maximum influent concentrations for each remediation area (i.e., influent treatment stream). If a remediation area included only one groundwater extraction component, flow rate-weighted averaging was not required and the initial/maximum component-specific concentrations estimated as described above were used.

Flow rate-weighted average nitrate concentrations for the combined WA influent for Years 1 through 5 are summarized in Attachment 11. Although influent nitrate concentrations for GE-WAA-02 and GE-WAA-05 increase over time, results of the flow rate-weighted averaging reveals that the maximum combined WA influent nitrate concentration still occurs at time zero (i.e., Ci = Cmax).

10.2 Influent Concentration Decay Analysis The estimated/calculated initial and maximum influent contaminant concentrations (Ci and Cmax, respectively), along with the parameters used to calculate estimated remediation durations (see Section 9.0), were used to predict declining influent concentrations and calculate operational timeframes for both the BA1 and WA treatment systems. The same first-order kinetic sorption equation used to calculate groundwater remediation durations (see Section 9.0) was used to model the decline in nitrate and uranium concentrations for influent streams associated with each remediation area contributing to the combined influent. The estimated maximum influent fluoride and Tc-99 concentrations are below the anticipated effluent discharge criterion. Therefore, a concentration decay analysis was not performed for these constituents.

To model long-term nitrate concentrations for the WAA U>DCGL influent stream, and its contribution to the combined WATF influent, the flow rate-weighted average, time-specific concentrations calculated for Years 1 through 4 were assumed as the initial nitrate influent concentration for each corresponding year. Due to the potential for influent nitrate concentrations to increase between Years 2 and 3, based on flow rate-weighted averaging results (see Section 10.1), WAA U>DCGL influent nitrate concentrations during the first three years of operation were held constant and the first-order kinetic concentration decay model was not applied. Following Year 3, the influent nitrate concentration was increased to the Year 4 time-specific concentration and the first-order kinetic concentration decay equation was applied to model continuous influent nitrate concentration reductions through the end of operations. The concentration decay model was applied to the 1206-NORTH nitrate influent concentration from the start of operations, with no nitrate expected in the influent after month 13. The results of the WA nitrate influent concentration decay analysis are presented in Attachment 12.

Based on the results of the WA uranium concentration decline analysis, the influent uranium groundwater concentration is not projected to fall below the MCL (30 pg/L)

Memorandum (coned) BURNS MCDONNELL October 7, 2022 Page 18 of 21 during the course of remediation. As described above in Section 9.0, groundwater extraction and uranium treatment will be discontinued in the WA after approximately 135 months.

Based on the results of the BA1 uranium concentration decline analysis, the influent uranium groundwater concentration is projected to fall below the MCL (30 pg/L) after approximately 126 months of remedial operations. Consequently, it is expected that the uranium treatment system will be bypassed after 126 months and recovered groundwater will be directly injected or discharged to Outfall 001 through the end of the 150-month groundwater remediation operation.

These concentration decay analyses were then used to estimate the operational timeframe required for the combined treatment train influent to reach the MCL for uranium, at which time treatment can be bypassed and the groundwater influent can be directly injected or discharged to the outfall. The results of the BA1 influent concentration decline analysis are presented in Attachment 13 and the results of the WA analysis are presented in Attachment 12. Calculation files in native (MS Excel) format can be provided to facilitate review of calculation methods (i.e., formulas, references, inputs, etc.) by NRC and DEQ personnel.

11.0 Combined Effluent Nitrate Concentration Calculations To determine the concentration of nitrate discharged at Outfall 001, a new flow rate-weighted average concentration was calculated for the initial nitrate concentration (Ci) and final nitrate concentration (Cf) once the WA treatment effluent is combined with the treatment effluent from BA1. Based on the proposed process, 8 gpm of treated effluent from WA will be re-injected via GWI-WU-01A, and 28 gpm of treated effluent from BA1 will be re-injected via GWI-BA1-01 through GWI-BA1-04. The combined WA/BA1 nitrate flow weight-rated average nitrate concentration was therefore based on a combined discharge rate of 171 gpm, equal to the sum of the WA and BA1 groundwater extraction flow rates, minus the treated water injection flow rate for each area. As described in Section 10.1, Ci is also projected to represent the maximum nitrate influent concentration during the treatment process. Results of the combined WA-BA1 effluent nitrate concentration estimates and decay analysis are presented in Attachment 14.

Based on the results of the combined WA-BA1 effluent concentration decline analysis, the nitrate groundwater concentration is expected to remain below the anticipated discharge limit (30 mg/L) throughout the groundwater remediation process.

12.0 Limitations and Assumptions Associated with Duration Estimates The accuracy of the groundwater remediation and water treatment duration estimates presented above are potentially limited by the quantity of available data, subsurface heterogeneity, variability in the concentration and distribution of contaminants in the aquifer units targeted for remediation, and other factors. In developing this basis of design, Bums & McDonnell and EPM consistently applied reasonably conservative assumptions to minimize the potential for

Memorandum (contd) BURNS f ^DONNELL October 7, 2022 Page 19 of 21 remediation and water treatment durations to be underestimated. This in turn reduced the probability that long-term remediation costs would be underestimated. These assumptions included the following:

• As discussed in Section 3.0, the 95% UCL concentration (if available), maximum contaminant concentration (if used in place of the 95% UCL value), or the average contaminant concentration (if data sufficient for determining the 95% UCL concentration were not available) was used for each monitor well and contaminant in developing the basis of design. This method of establishing groundwater concentrations was selected to address variability in the concentrations of contaminants in the aquifer units targeted for remediation.

• As discussed in Section 9.0, conservatively high bulk soil density, distribution coefficient (Kd), and saturated thickness values were applied in remediation duration estimates.

• As discussed in Section 9.0, the larger of the following concentration values were used as the initial groundwater concentration for the purposes of estimating the remediation timeframe required for each area:

o The maximum representative concentration reported for any well within the remediation area (determined as described in Section 3.0) o The concentration estimated by conducting area-weighted averaging of representative concentrations within the remediation area (determined as described in Section 8.0)

• As discussed in Section 8.0, the lateral extent of remediation areas was extended to the limit of impacts exceeding the uranium MCL (30 pg/L). Because the uranium remediation criterion is 180 pCi/L, this assumption results in a larger (i.e., more conservative) pore volume input for remediation and water treatment duration calculations.

• As discussed in Section 7.0, the pore volume calculated for use in the nitrate influent concentration decay analysis included the entire estimated capture area. This assumption results in a relatively large pore volume input for water treatment duration calculations.

• The methods used to estimate remediation and water treatment durations assume contaminants are evenly distributed throughout the entire saturated thickness of each remediation area. Previous investigation activities have demonstrated that contaminants are likely to be stratified within alluvium and TZ formations at the Site.

In order optimize remediation and water treatment efficiency, additional contaminant and hydraulic conductivity profiling will be conducted at each alluvial extraction well location, prior to well installation, and extraction wells will be constructed with

Memorandum (contd) BURNS MCDONNELL October 7, 2022 Page 20 of 21 screen intervals focused on zones exhibiting uranium concentrations exceeding remediation criteria. This well construction approach is likely to result in mass removal rates that are higher than those predicted by the duration estimate models since groundwater extraction efforts will be focused on aquifer intervals containing the greatest contaminant mass. It should be noted that in-process and post-remediation monitoring will be conducted using results for groundwater samples collected from monitor wells screened across the full extent of the saturated zone.

While focusing alluvial extraction well screen intervals on zones of elevated contaminant concentration could result in water treatment influent concentrations higher than currently predicted (i.e., predicted concentrations are based on sample results from monitor wells with screen intervals that fully penetrate the saturated alluvium), the influent and effluent concentrations presented in Attachments 12, 13, and 14 are considered sufficiently conservative. In addition, the ion exchange treatment systems specified for uranium removal are capable of treating water with uranium concentrations significantly higher than predicted, and the uranium treatment systems will be closely monitored, particularly during the initial phases of remediation, for appropriate contaminant removal efficiencies and achievement of discharge criteria. Ion exchange treatment systems will also be monitored for U-235 accumulation.

The maximum combined fluoride and Tc-99 influent concentrations for the WA treatment system are 2.6 mg/L and 1.26 ng/L, respectively. This fluoride concentration is below the anticipated permitted discharge limit for fluoride (10 mg/L). Tc-99 is not anticipated to be limited in the system discharge, and the estimated influent Tc-99 concentrations are below the drinking water standard.

However, WA treatment system influent concentrations will be monitored closely to assess the potential for exceedances.

Attachments:

Attachment 1 - Nitrate, Uranium, Tc-99, and Fluoride Data Sheets Attachment 2 - BA1 and WA Contaminant Isopleth Maps: Nitrate, Uranium, Tc-99, and Fluoride Attachment 3 - BA1 and WA Particle Tracking Results Attachment 4 - BA1 Remediation Component Locations Attachment 5 - WA Remediation Component Locations Attachment 6 - Area and Linear-Weighted Averaging Results Attachment 7 - Remediation and Water Treatment Summary Schedule Attachment 8 - Remediation Duration Estimate Calculations: BA1 Attachment 9 - Remediation Duration Estimate Calculations: WA Attachment 10 - Nitrate Time-Weighted Concentration Averaging Results

Memorandum (contd) burn s msdon nell October 7, 2022 Page 21 of 21 Attachment 11 - Nitrate Flow Rate-Weighted Concentration Averaging Results Attachment 12 - WA Influent Concentration Analysis Results Attachment 13 - BA1 Influent Concentration Analysis Results Attachment 14 - WA-BA1 Nitrate Combined Effluent Analysis Results

- Nitrate, Uranium, Fluoride, and Tc-99 Data Sheets Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L) 02W01 0.474 0.4740 0.4740 02W02 02W03 0.651 0.6510 0.6510 02W04 0.765 0.7650 0.7650 02W05 0.550 0.5500 0.5500 02W06 0.503 0.483 0.4147 0.4830 02W07 0.484 0.4840 0.4840 02W08 02W09 1.040 0.985 0.8920 0.9850 02W10 02W11 02W12 02W13 02W14 0.513 0.5130 0.5130 02W15 0.727 0.7270 0.7270 02W16 02W17 02W18 0.459 0.4590 0.4590 02W19 0.486 0.4860 0.4860 02W20 02W21 02W22 02W23 02W24 02W25 02W26 02W27 0.565 02W28 0.789 0.742 0.6886 0.7420 02W29 0.673 0.6730 0.6730 02W30 0.724 0.7240 0.7240 02W31 0.638 0.6380 0.6380 02W32 0.769 0.726 0.5940 0.7260 02W33 02W34 02W35 02W36 02W37 0.443 0.4430 0.4430 02W38 0.506 0.5060 0.5060 02W39 0.716 0.7160 0.7160 02W40 0.654 0.6540 0.6540 02W41 0.519 0.5190 0.5190 02W42 0.601 0.541 0.4761 0.5410 02W43 0.449 0.435 0.4067 0.4350 02W44 0.571 0.546 0.4883 0.5460 Page 1 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L) 02W45 0.413 0.4130 0.4130 02W46 1.180 1.1800 1.1800 02W47 02W48 02W50 02W51 02W52 02W53 02W62 1311 0.561 0.4773 0.4773 1312 12.200 10.46 9.4440 10.4600 1313 55.800 48.9 46.3300 48.9000 1314 0.329 0.318 0.2846 0.3180 1315R 2.000 2.0000 2.0000 1316R 0.549 0.5490 0.5490 1319A-1 1319A-2 0.366 0.3415 0.3415 1319A-3 1319B-1 0.348 0.337 0.3206 0.3370 1319B-2 0.455 0.447 0.4010 0.4470 1319B-3 0.314 0.307 0.2850 0.3070 1319B-4 0.424 0.412 0.3486 0.4120 1319B-5 0.430 0.403 0.3414 0.4030 1319C-1 1319C-2 1319C-3 1320 0.643 0.5750 0.5750 1321 0.303 0.2933 0.2933 1322 0.549 0.5490 0.5490 1323 1324 0.530 0.5153 0.5153 1325 0.522 0.5055 0.5055 1326 0.322 0.3130 0.3130 1327B 0.348 0.3355 0.3355 1328 1329 0.480 0.4125 0.4125 1330 0.629 0.6095 0.6095 1331 0.557 0.5570 0.5570 1332 1333 0.705 0.7050 0.7050 1334 0.602 0.5533 0.5533 1335A 0.386 0.3577 0.3577 1336A 9.890 9.627 9.0717 9.6270 1337 14.400 14.16 12.1050 14.1600 Page 2 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L) 1338 0.879 0.878 0.7723 0.8780 1339 1340 20.900 18 15.0667 18.0000 1341 0.687 0.645 0.5910 0.6450 1342 0.050 1343 0.406 0.3950 0.3950 1344 0.384 0.3840 0.3840 1345 0.530 0.534 0.4870 0.5300 1346 10.600 9.641 8.8509 9.6410 1347 4.950 4.753 4.3860 4.7530 1348 9.770 8.858 8.4882 9.7700 1349 1.030 1.016 0.7915 1.0300 1350 1.590 1.5900 1.5900 1351 1.280 1.063 0.8170 1.0630 1352 0.589 0.528 0.4608 0.5280 1353 1.720 1.795 1.1608 1.7200 1354 0.520 0.499 0.4580 0.4990 1355 0.439 0.4390 0.4390 1356 0.981 0.739 0.5421 0.7390 1357 0.557 0.5555 0.5555 1358 0.335 0.3350 0.3350 1359 0.973 0.9730 0.9730 1360 1.600 1.6000 1.6000 1361 0.513 0.4675 0.4675 1362 1363 0.447 0.4115 0.4115 1364 0.424 0.4240 0.4240 1365 0.504 0.4770 0.4770 1366 0.492 0.4830 0.4830 T-51 0.452 0.4385 0.4385 T-52 1.640 1.5400 1.5400 T-53 0.934 0.8850 0.8850 T-54 2.440 2.228 1.6720 2.2280 T-55 2.410 2.193 1.8240 2.1930 T-56 1.020 0.984 0.8928 0.9840 T-57 5.030 4.636 4.3470 4.6360 T-58 0.887 0.861 0.7325 0.8610 T-59 0.405 0.3283 0.3283 T-60 0.496 0.4845 0.4845 T-61 0.498 0.4560 0.4560 T-62 4.410 3.747 3.4091 3.7470 T-63 5.740 5.279 4.3660 5.2790 T-64 3.450 2.506 1.6803 2.5060 T-65 3.290 3.219 2.8700 3.2190 Page 3 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L)

T-66 1.850 1.841 1.5750 1.8410 T-67 2.700 2.77 2.4200 2.7000 T-68 1.760 1.724 1.5400 1.7240 T-69 1.290 1.244 1.0216 1.2440 T-70R 1.440 1.327 1.1417 1.3270 T-72 1.420 1.395 1.2525 1.3950 T-73 0.320 0.3200 0.3200 T-74 0.329 0.3290 0.3290 T-75 0.895 0.8440 0.8440 T-76 3.010 2.929 2.8609 2.9290 1-77 1.220 1.085 0.9936 1.0850 T-78 0.365 0.3650 0.3650 T-79 1.000 0.898 0.7960 0.8980 T-81 0.415 0.4150 0.4150 T-82 0.585 0.49 0.4404 0.4930 T-83 0.397 0.3970 0.3970 T-84 0.800 0.7900 0.7900 T-85 1.490 1.4467 1.4467 T-86 3.170 3.032 2.3475 3.0320 T-87 1.300 1.28 1.1480 1.2800 T-88 1.370 1.261 1.0558 1.2610 T-89 0.559 0.5050 0.5050 T-90 0.737 0.7065 0.7065 T-91 0.622 0.5837 0.5837 T-93 0.518 0.4680 0.4680 T-94 0.555 0.5395 0.5395 T-95 1.640 1.5650 1.5650 T-96 0.533 0.5330 0.5330 TMW-01 0.607 0.6070 0.6070 TMW-02 TMW-05 TMW-06 TMW-07 TMW-08 0.563 0.502 0.4506 0.5020 TMW-09 0.874 0.744 0.6559 0.7440 TMW-13 0.796 0.711 0.6047 0.7110 TMW-17 TMW-18 0.340 0.3400 0.3400 TMW-19 TMW-20 TMW-21 TMW-23 TMW-24 0.448 0.4160 0.4160 TMW-25 0.375 0.3750 0.3750 Page 4 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L)

CDW-1 CDW-1A Abandonded CDW-2 Abandonded CDW-2A Abandonded CDW-3 Abandonded CDW-3A Abandonded CDW-4 Abandonded CDW-4A Abandonded CDW-5 Abandonded CDW-5A Abandonded CDW-6 Abandonded CDW-6A Abandonded CDW-7 Abandonded CDW-7A Abandonded GE-BA1-01 Abandonded GE-WA-01 Abandonded MWWA-03 13.300 9.663 7.7222 9.6630 MWWA-09 4.200 3.965 3.8027 3.9650 1370 0.449 0.4490 0.4490 1371 0.405 0.4050 0.4050 1367 0.469 0.4690 0.4690 T-97 0.385 0.3850 0.3850 T-98 0.340 0.3400 0.3400 T-99 0.552 0.5520 0.5520 T-100 0.772 0.7720 0.7720 T-101 0.534 0.5340 0.5340 T-102 0.315 0.3150 0.3150 T-103 0.356 0.3560 0.3560 1368 0.458 0.4580 0.4580 1372 0.422 0.4220 0.4220 1373 0.369 0.3690 0.3690 1374 1375 0.386 0.3710 0.3710 1376 0.713 0.5640 0.5640 1377 0.464 0.4640 0.4640 1378 0.281 0.2810 0.2810 1379 0.754 0.7250 0.7250 1380 0.505 0.5050 0.5050 1381 2.120 1.6477 1.6477 1382 0.507 0.4817 0.4817 1383 19.400 11.7633 11.7633 1384 0.455 0.4307 0.4307 1385 9.680 7.651 6.6288 7.6510 1386 0.453 0.4370 0.4370 Page 5 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Fluoride Concentration (mg/L) 1387 9.240 8.206 7.3438 8.2060 1388 2.160 1.9300 1.9300 1389 0.211 0.1753 0.1753 1390 1.070 0.9607 0.9607 1391 3.430 2.8533 2.8533 1392 0.698 0.6860 0.6860 1393 21.300 11.89 7.3700 11.8900 1394 0.399 0.3820 0.3820 T-92R 0.407 0.3960 0.3960 1369 0.430 0.4300 0.4300 Page 6 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L) 02W01 0.353 0.3530 0.3530 02W02 02W03 0.683 0.6830 0.6830 02W04 0.192 0.1920 0.1920 02W05 0.050 0.0500 0.0500 02W06 0.202 0.139 0.0780 0.1390 02W07 0.185 0.1850 0.1850 02W08 02W09 0.774 0.458 0.2463 0.4580 02W10 02W11 02W12 02W13 02W14 0.050 0.0500 0.0500 02W15 0.534 0.5340 0.5340 02W16 02W17 02W18 0.050 0.0500 0.0500 02W19 0.050 0.0500 0.0500 02W20 02W21 02W22 02W23 02W24 02W25 02W26 02W27 1.590 1.5900 1.5900 02W28 0.500 0.239 0.1135 0.2390 02W29 13.400 13.4000 13.4000 02W30 2.520 2.5200 2.5200 02W31 0.050 0.0500 0.0500 02W32 0.921 0.505 0.2188 0.5050 02W33 02W34 02W35 02W36 02W37 0.050 0.0500 0.0500 02W38 0.160 0.1600 0.1600 02W39 0.173 0.1730 0.1730 02W40 0.223 0.2230 0.2230 02W41 0.722 0.7220 0.7220 02W42 7.690 4.083 2.1141 4.0830 02W43 0.500 0.339 0.1878 0.3390 02W44 0.800 0.589 0.3390 0.5890 Page 1 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L) 02W45 0.019 0.0191 0.0191 02W46 0.053 0.0529 0.0529 02W47 02W48 02W50 02W51 02W52 02W53 02W62 1311 30.000 21.5667 21.5667 1312 465.000 379.7 352.3000 379.7000 1313 464.000 240.3 172.9000 240.3000 1314 2.040 1.869 1.6600 1.8690 1315R 9.820 9.8200 9.8200 1316R 10.900 10.9000 10.9000 1319A-1 1319A-2 33.000 31.9000 31.9000 1319A-3 1.620 1.6200 1.6200 1319B-1 85.500 57.44 47.4700 57.4400 1319B-2 2.680 2.699 2.3875 2.6800 1319B-3 90.100 75.79 69.5818 75.7900 1319B-4 3.770 3.699 3.3280 3.6990 1319B-5 13.100 11.33 8.7320 11.3300 1319C-1 1319C-2 1319C-3 1320 18.600 19.14 17.0500 18.6000 1321 0.826 0.7560 0.7560 1322 19.400 19.4000 19.4000 1323 1324 6.450 3.7600 3.7600 1325 20.500 19.6500 19.6500 1326 33.800 27.1000 27.1000 1327B 38.700 36.3667 36.3667 1328 1329 33.000 31.3667 31.3667 1330 16.000 13.0633 13.0633 1331 10.100 10.1000 10.1000 1332 1333 4.190 4.1900 4.1900 1334 6.810 5.8300 5.8300 1335A 2.770 2.5033 2.5033 1336A 414.000 376.6 323.5000 376.6000 Page 2 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L) 1337 63.700 53.34 43.1500 53.3400 1338 10.500 7.0133 7.0133 1339 1340 66.500 53.77 44.9667 53.7700 1341 29.300 28.63 25.3800 28.6300 1342 0.050 0.0500 0.0500 1343 6.890 6.448 4.6225 6.4480 1344 0.050 0.0500 0.0500 1345 7.800 7.663 6.5080 7.6630 1346 499.000 406.5 357.3636 406.5000 1347 95.900 64.97 28.2600 64.9700 1348 16.500 11.57 10.0609 11.5700 1349 21.500 20.21 11.0800 20.2100 1350 15.600 11.7333 11.7333 1351 87.400 76.09 59.3000 76.0900 1352 61.500 54.99 49.1700 54.9900 1353 7.750 8.789 5.5100 7.7500 1354 190.000 141.8 106.1143 141.8000 1355 14.500 14.0333 14.0333 1356 18.800 14.77 12.4127 14.7700 1357 55.400 51.99 38.1500 51.9900 1358 20.600 16.9333 16.9333 1359 23.100 21.7333 21.7333 1360 16.400 13.4167 13.4167 1361 0.080 0.0651 0.0651 1362 1363 0.141 0.0913 0.0913 1364 0.050 0.0500 0.0500 1365 0.091 0.0857 0.0857 1366 0.147 0.1224 0.1224 T-51 16.000 14.73 8.5700 14.7300 T-52 58.000 56.69 30.0250 56.6900 T-53 47.700 47.7 41.7500 47.7000 T-54 431.000 238.6 179.5800 238.6000 T-55 281.000 236 134.0000 236.0000 T-56 26.400 24.89 21.0800 24.8900 T-57 125.000 111.5 98.0900 111.5000 T-58 61.000 44.87 35.8333 44.8700 T-59 150.000 112.4 100.8400 112.4000 T-60 101.000 97.42 74.8500 97.4200 T-61 56.800 34.93 25.4580 34.9300 T-62 143.000 88 66.7727 88.0000 T-63 150.000 138.6 80.1800 138.6000 Page 3 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L)

T-64 20.700 14.03 9.5500 14.0300 T-65 55.500 56.7 51.6750 55.5000 T-66 40.300 40.73 32.1500 40.3000 T-67 29.400 26.98 17.4000 26.9800 T-68 21.400 21.22 17.4400 21.2200 T-69 140.000 72.14 53.0200 72.1400 T-70R 6.920 4.407 3.1057 4.4070 T-72 25.800 27.82 14.0125 25.8000 T-73 0.034 0.0282 0.0282 T-74 1.570 1.4700 1.4700 T-75 1.970 1.6633 1.6633 T-76 47.800 30.35 26.0364 30.3500 T-77 5.500 3.068 2.1665 3.0680 T-78 0.251 0.1639 0.1639 T-79 3.560 1.258 0.7224 1.2580 T-81 0.074 0.0710 0.0710 T-82 0.086 0.0677 0.0532 0.0677 T-83 0.063 0.0542 0.0542 T-84 51.000 46.54 30.0250 46.5400 T-85 123.000 100.4 64.9800 100.4000 T-86 58.000 43.88 36.5778 43.8800 T-87 110.000 108.4 80.0400 108.4000 T-88 130.000 75.36 58.9700 75.3600 T-89 72.500 68.53 60.7400 68.5300 T-90 34.500 35.2 27.5750 34.5000 T-91 38.900 30.87 25.4300 30.8700 T-93 58.500 54.5 39.1500 54.5000 T-94 18.900 18.7 16.2250 18.7000 T-95 49.000 49.17 38.6750 49.0000 T-96 33.000 31.58 27.3750 31.5800 TMW-01 0.172 0.1720 0.1720 TMW-02 TMW-05 TMW-06 TMW-07 TMW-08 2.630 2.189 1.8543 2.1890 TMW-09 1.280 0.633 0.2893 0.6330 TMW-13 0.500 0.342 0.2025 0.3420 TMW-17 TMW-18 0.374 0.3740 0.3740 TMW-19 TMW-20 TMW-21 TMW-23 Page 4 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L)

TMW-24 0.050 0.0356 0.0356 TMW-25 1.470 1.4700 1.4700 CDW-1 Abandonded CDW-1A Abandonded CDW-2 Abandonded CDW-2A Abandonded CDW-3 Abandonded CDW-3A Abandonded CDW-4 Abandonded CDW-4A Abandonded CDW-5 Abandonded CDW-5A Abandonded CDW-6 Abandonded CDW-6A Abandonded CDW-7 Abandonded CDW-7A Abandonded GE-BA1-01 GE-WA-01 MWWA-03 84.600 42.37 25.1172 42.3700 MWWA-09 56.000 43.05 34.9364 43.0500 1370 0.040 0.0404 0.0404 1371 0.050 0.0500 0.0500 1367 0.035 0.0354 0.0354 T-97 13.800 10.22 6.8763 10.2200 T-98 2.000 0.8617 0.8617 T-99 46.600 37.37 31.0625 37.3700 T-100 51.600 39.49 30.6125 39.4900 T-101 36.500 27.2333 27.2333 T-102 24.400 22.2667 22.2667 T-103 8.640 4.0198 4.0198 1368 0.050 0.0500 0.0500 1372 0.050 0.0500 0.0500 1373 0.050 0.0500 0.0500 1374 27.300 27.3000 27.3000 1375 37.900 34.2667 34.2667 1376 17.700 17.0000 17.0000 1377 8.730 8.7300 8.7300 1378 8.550 8.5500 8.5500 1379 7.370 7.3700 7.3700 1380 17.100 17.1000 17.1000 1381 881.000 839.1 790.8750 839.1000 1382 3.060 2.4400 2.4400 1383 308.000 226.6667 226.6667 1384 0.505 0.4003 0.4003 Page 5 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Nitrate Concentration (mg/L) 1385 1,200.000 1006 876.5000 1006.0000 1386 17.600 15.4333 15.4333 1387 71.900 60.17 47.2875 60.1700 1388 10.400 9.1500 9.1500 1389 31.600 21.6667 21.6667 1390 7.030 4.8933 4.8933 1391 5.250 4.0850 4.0850 1392 1.560 1.1093 1.1093 1393 505.000 274.9 153.1750 274.9000 1394 5.140 4.2500 4.2500 T-92R 40.500 36.2500 36.2500 1369 0.017 0.0173 0.0173 Page 6 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L) 02W01 2,720.0 2,495 2,217 2495 02W02 2,345.9 2,128 2,128 02W03 1,190.0 862 862 02W04 497.0 300.9467 300.95 02W05 638.1 388.2333 388.23 02W06 1,950.0 1310 548.2800 1,310.00 02W07 1,478.0 924 924 02W08 744.0 429.3 268.9600 429.30 02W09 10.0 6.965 4.1978 6.97 02W10 4.4 3.9908 3.99 02W11 311.0 136.2610 136.26 02W12 448.0 203.4697 203.47 02W13 33.8 28.3637 28.36 02W14 305.5 278.5033 278.50 02W15 261.0 100.5027 100.50 02W16 20.2 17.38 11.6140 17.38 02W17 15.7 13.94 11.8400 13.94 02W18 504.0 289.0133 289.01 02W19 1,305.9 711.6333 711.63 02W20 1.5 1.2368 1.24 02W21 5.5 5.4850 5.49 02W22 10.5 8.6250 8.63 02W23 7.4 7.2400 7.24 02W24 15.7 13.2763 13.28 02W25 28.4 18.9760 18.98 02W26 7.1 4.0421 4.04 02W27 188.0 134.5 94.8733 134.50 02W28 428.0 352.5 296.7350 352.50 02W29 1,570.0 1,115 1,115 02W30 338.0 309.6500 309.65 02W31 997.0 861 861 02W32 3,410.0 1,577 949 1,577 02W33 31.1 17.4460 17.45 02W34 5.6 4.9700 4.97 02W35 29.3 24.51 18.1200 24.51 02W36 18.6 15.1800 15.18 02W37 789.4 333.3833 333.38 02W38 392.0 255.4133 255.41 02W39 851.0 613.1 504.2600 613.10 02W40 1,430.0 1,137 1,001 1,137 02W41 517.0 420.6067 420.61 02W42 516.0 407.6 248.5517 407.60 02W43 134.0 124.2 99.8400 124.20 02W44 945.0 506.2 360.9044 506.20 Page 1 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L) 02W45 62.4 48.6243 48.62 02W46 4,330.0 2,663 2,663 02W47 342.0 264.2467 264.25 02W48 27.0 27.1 26.0710 27.00 02W50 4.0 3.8450 3.85 02W51 4.6 4.5200 4.52 02W52 2.5 2.2750 2.28 02W53 63.6 41.6280 41.63 02W62 5.6 5.0700 5.07 1311 2.9 2.7195 2.72 1312 22.3 22.11 19.3693 22.11 1313 18.8 19.9 15.2885 18.80 1314 1.4 1.274 1.1700 1.27 1315R 1,510.0 1,103 881 1,103 1316R 144.0 137.2367 137.24 1319A-1 1319A-2 11.0 6.2751 6.28 1319A-3 5.8 5.7997 5.80 1319B-1 42.8 38.01 28.9918 38.01 1319B-2 1.4 1.445 1.3451 1.41 1319B-3 31.0 28.53 26.6360 28.53 1319B-4 1.6 1.621 1.5215 1.62 1319B-5 2.6 2.445 2.1298 2.45 1319C-1 1319C-2 1319C-3 1320 2.2 2.204 2.0139 2.20 1321 11.0 10.7333 10.73 1322 19.9 12.8343 12.83 1323 1324 1.8 1.6209 1.62 1325 1.0 0.9375 0.94 1326 5.5 4.1996 4.20 1327B 4.4 4.0995 4.10 1328 1329 4.9 4.3892 4.39 1330 6.1 5.6513 5.65 1331 36.8 32.12 27.6421 32.12 1332 1333 21.7 20.9777 20.98 1334 16.2 11.4740 11.47 1335A 8.0 6.0887 6.09 1336A 39.8 36.14 30.3278 36.14 1337 7.0 6.688 5.5819 6.69 Page 2 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L) 1338 0.8 0.7640 0.76 1339 1340 9.0 8.456 7.6270 8.46 1341 2.4 2.359 2.2038 2.36 1342 4.9 4.9422 4.94 1343 21.9 21.28 17.6058 21.28 1344 2.4 1.9633 1.96 1345 2.2 2.081 1.8054 2.08 1346 7.0 5.457 3.4180 5.46 1347 40.3 34.45 24.0490 34.45 1348 73.5 71.26 69.6464 71.26 1349 30.0 29.62 19.5160 29.62 1350 19.4 14.2513 14.25 1351 1,547.6 874.5 412.4571 874.50 1352 149.0 124.9 102.4046 124.90 1353 44.7 50.29 25.2725 44.68 1354 3.1 3.046 2.8494 3.05 1355 2.6 2.5763 2.58 1356 1,260.2 572.4 394.6864 572.40 1357 2.2 2.193 1.9486 2.16 1358 1.7 1.5702 1.57 1359 14.3 12.0857 12.09 1360 39.3 23.9407 23.94 1361 271.0 172.9 117.8241 172.90 1362 77.7 40.1847 40.18 1363 104.0 111.1 73.9918 104.00 1364 15.9 7.1612 7.16 1365 123.0 100.9 80.2549 100.90 1366 6.0 5.54 3.6919 5.54 T-51 36.8 36.37 28.0220 36.37 T-52 23.5 23.21 19.9468 23.21 T-53 33.6 34.41 27.6440 33.60 T-54 4.1 3.785 3.1545 3.79 T-55 8.5 7.391 5.6136 7.39 T-56 7.4 5.773 3.7763 5.77 T-57 14.5 13.61 12.1542 13.61 T-58 20.4 19.92 17.4588 19.92 T-59 101.0 92.26 87.4233 92.26 T-60 50.1 48.59 42.2678 48.59 T-61 35.0 30.44 27.6090 30.44 T-62 238.0 177.8 159.2327 177.80 T-63 104.2 104.8 83.9900 104.15 T-64 208.0 125.7 77.0700 125.70 T-65 156.0 152 135.7775 152.00 Page 3 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L)

T-66 123.0 121.6 98.6600 121.60 T-67 159.0 159.6 140.8975 159.00 T-68 162.0 150.2 131.3200 150.20 T-69 92.3 77.29 65.6090 77.29 T-70R 119.0 97.71 79.1283 97.71 T-72 142.0 141 118.0350 141.00 T-73 11.9 10.3976 10.40 T-74 16.1 13.8050 13.81 T-75 86.4 76.7367 76.74 T-76 194.0 173.2 163.6891 173.20 T-77 95.8 86.79 78.7345 86.79 T-78 21.8 17.4677 17.47 T-79 77.0 62.76 56.1982 62.76 T-81 12.7 11.0281 11.03 T-82 37.6 34.28 31.2042 34.28 T-83 15.1 14.3363 14.34 T-84 48.1 48.6 44.9458 48.10 T-85 27.8 28.09 25.1590 27.80 T-86 25.4 22.91 19.5178 22.91 T-87 24.1 21.99 18.8868 21.99 T-88 10.2 9.943 9.3855 9.94 T-89 52.1 50.65 46.4850 50.65 T-90 25.0 24.82 23.5475 24.82 T-91 28.0 27.82 25.5998 27.82 T-93 33.5 32.68 29.0985 32.68 T-94 20.2 20.9 18.4360 20.24 T-95 29.5 29.25 27.8630 29.25 T-96 36.1 34.73 33.4118 34.73 TMW-01 767.0 462.5667 462.57 TMW-02 5.4 3.7566 3.76 TMW-05 3.9 3.5830 3.58 TMW-06 2.4 2.2583 2.26 TMW-07 221.0 210.3733 210.37 TMW-08 3,230.0 2589 1,670 2,589 TMW-09 3,760.0 2,975 2,750 2,975 TMW-13 4,510.0 3516 2,090 3,516 TMW-17 7.9 4.5299 4.53 TMW-18 17.2 14.7947 14.79 TMW-19 48.2 48.2170 48.22 TMW-20 8.9 6.4000 6.40 TMW-21 96.6 62.3787 62.38 TMW-23 6.8 6.909 6.2923 6.76 TMW-24 82.3 68.34 57.7092 68.34 TMW-25 123.0 116.4167 116.42 Page 4 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L)

CDW-1 Abandonded CDW-1A Abandonded CDW-2 Abandonded CDW-2A Abandonded CDW-3 Abandonded CDW-3A Abandonded CDW-4 Abandonded CDW-4A Abandonded CDW-5 Abandonded CDW-5A Abandonded CDW-6 Abandonded CDW-6A Abandonded CDW-7 Abandonded CDW-7A Abandonded GE-BA1-01 Abandonded GE-WA-01 Abandonded MWWA-03 666.0 526.6 431.2667 526.60 MWWA-09 156.0 139.8 130.6627 139.80 1370 15.5 7.2520 7.25 1371 31.3 27.8763 27.88 1367 13.1 8.3432 8.34 T-97 67.8 64.07 61.4413 64.07 T-98 63.3 53.0600 53.06 T-99 48.1 42.06 38.2223 42.06 T-100 31.6 29.0630 29.06 T-101 36.0 34.7830 34.78 T-102 33.2 32.3393 32.34 T-103 11.1 10.1850 10.18 1368 8.6 5.8936 5.89 1372 10.5 9.3553 9.36 1373 64.3 51.21 40.9325 51.21 1374 12.8 12.8230 1375 4.7 3.5549 3.55 1376 27.1 15.4350 15.44 1377 20.3 16.4543 16.45 1378 2.4 2.2522 2.25 1379 19.9 18.3437 18.34 1380 11.1 10.4790 10.48 1381 92.5 81.92 72.2913 81.92 1382 1.3 1.2550 1.26 1383 13.5 10.0430 10.04 1384 0.7 0.6345 0.63 1385 20.4 18.9790 18.98 1386 1.3 1.2300 1.23 Page 5 of 6

Max Observed Representative Monitor Value 95% UCL Well Average Concentration Well Uranium Concentration (ug/L) 1387 23.7 20.3647 20.36 1388 1.4 1.3500 1.35 1389 2.3 1.4023 1.40 1390 1.5 1.5400 1.54 1391 1.8 1.6600 1.66 1392 1.1 1.0450 1.05 1393 35.0 24.2 18.0671 24.20 1394 1.0 1.0005 1.00 Page 6 of 6

Tc-99 Data Table 1/30/2020 Cimarron Remediation Site Technetium-99 Activity and Mass Concentration Results Lab or Activity Mass Collection Uncertainty Data MDC Area Location ID Concentration Concentration Date (pCi/L) Review (pCi/L)

(pCi/L) (ng/L)1'2 Qual T-62 8/26/2019 80.1 4.7 30.9 48.7 WAA T-64 8/26/2019 24.4 1.4 23 U 38.3 U>DCGL T-76 8/26/2019 101 5.9 27.3 41.3 T-79 8/26/2019 -1.59 N/A 22.1 u, R 38.5 WAA-T-97 9/3/2019 24.8 1.5 24.5 u 41 WEST T-54 9/3/2019 567 33.4 43.8 47.8 T-55 9/3/2019 341 20.1 35.2 43 T-56 9/3/2019 45.6 2.7 26.4 43.1 WAA- T-57 9/3/2019 185 10.9 33.7 47.8 BLUFF T-58 9/3/2019 368 21.6 36.4 43.6 T-63 9/3/2019 272 16.0 34.1 44.2 T-86 9/3/2019 57.5 3.4 26.3 42.1 T-87 9/3/2019 175 10.3 31 43.7 T-59 9/3/2019 15.2 0.9 25.6 U 43.5 WAA-T-60 9/3/2019 46.4 2.7 25.7 41.8 EAST T-90 9/3/2019 19.5 1.1 25.1 u 42.4 WU-1348 9/4/2019 -6.01 N/A 26.8 u, R 46.9 1348 1312 9/4/2019 662 38.9 40.8 40 1313 9/4/2019 251 14.8 32.4 42.4 wu- 32.1 39.5 1313DUP 9/4/2019 299 17.6 UP1 1395 9/4/2019 -16.5 N/A 25.1 u, R 44.7 1396 9/4/2019 -9.17 N/A 25.8 U, R 45.4 1336A 9/4/2019 982 57.8 48.1 40.7 1336ADUP 9/4/2019 963 56.6 48.5 41.7 1337 9/4/2019 -13.4 N/A 22.8 U, R 40.6 1346 9/5/2019 1650 97.1 59.4 40.9 wu- 1346DUP 9/5/2019 1600 94.1 58.3 40.5 UP2 1347 9/4/2019 4.98 0.3 24.7 U 42.7 1387 9/4/2019 23.5 1.4 25.5 u 42.9 1389 9/4/2019 35.4 2.1 24.6 u 40.4 1401 9/5/2019 705 41.5 44.5 43.6 1402 9/5/2019 941 55.4 49.8 44.1 1351 8/26/2019 28.2 1.7 23.5 u 39.1 WU- 1351DUP 8/26/2019 13.2 0.8 23 u 39.2 BA3 1352 8/26/2019 12.3 0.7 22.2 u 37.7 1356 8/26/2019 51.4 3.0 24.1 38.7 WU- 1319B-1 9/4/2019 5.26 0.3 25.2 u 43.5 PBA 1319B-2 9/4/2019 -9.58 N/A 22.9 U, R 40.5 Page 1 of 2

Tc-99 Data Table 1/30/2020 Cimarron Remediation Site Technetium-99 Activity and Mass Concentration Results Lab or Activity Mass Collection Uncertainty Data MDC Area Location ID Concentration Concentration Date (pCi/L) Review (pCi/L)

(pCi/L) (ng/L)1'2 Qual 1206- MWWA-03 8/27/2019 11.4 0.7 22.8 U 38.9 NORTH MWWA-09 8/27/2019 46 2.7 24.7 40 1201 SURFACE (Upstream) 8/27/2019 -1.8 N/A 22.5 u, R 39.2 WATER 1202 8/27/2019 2.27 0.1 27.3 U 47.3 (Downstream) 1314 8/27/2019 -5.81 N/A 21.5 U. R 37.7 1315R 9/5/2019 23 1.4 24.4 U 40.9 BA1-A TMW-08 8/28/2019 -4 N/A 22.4 U, R 39.1 TMW-09 8/28/2019 12.5 0.7 22.2 u 37.7 TMW-09DUP 8/28/2019 -8.09 N/A 23.5 U, R 41.3 02W06 8/27/2019 -5.14 N/A 21.2 U, R 37.2 02W08 8/28/2019 6.17 0.4 21.7 U 37.3 02W19 9/5/2019 11.2 0.7 22.8 u 38.9 BA1-B 02W44 8/28/2019 -3.96 N/A 23.6 U, R 41.2 1363 9/5/2019 4 0.2 23.8 u 41.2 TMW-13 8/28/2019 -4.22 N/A 21.2 u, R 37.2 TMW-24 9/5/2019 -17.2 N/A 22 U, R 39.4 Notes:

Activity to mass conversion factor for Tc-99 is 1.7E-02 Ci/g (17 pCi/ng) [49 CFR 173.435 Table of A1 and A2 values for radionuclides].

2Any results qualified with a U were adjusted to the MDC of 50 pCi/L (2.9 ng/L) in subsequent assessments.

Itc -99 exceeds 900 pCi/L (MCL)

Red bold font indicates qualifier was added during internal data validation Qualifier Definitions:

J - Qualified as estimated during the data evaluation R - Rejected during the reasonableness review U - Analyte not detected above the minimum detectable concentration (MDC)

MDC - Minimum Detectable Concentration pCi/L - PicoCuries per liter ng/L - Nanograms per liter Page 2 of 2

- BA1 and WA Contaminant Isopleth Maps: Nitrate, Uranium, Fluoride, and Tc-99

Water Treatment Design Basis 9/21/22 Cimmaron Environmental Response Trust Sandstone A Fluoride Isoconcentration Map (mg/L) 800 700 600 500 400 300 200 100 0

I I Sandstone A Monitor Wells 0 Sandstone B/Alluvial Monitor Wells

= Remediation Trench Location

-j- Western Area Extraction Wells Western Area Injection Wells 0 500 1000 1500 2000

9/21/22 Water Treatment Design Basis Cimmaron Environmental Response Trust Sandstone B, Transition Zone, and Alluvium Fluoride Isoconcentration Map (mg/L) 500 1000 1500 2000 CREATED 09/12/2022 BY BURNS & MCDONNELL ENGINEERING

9/21/22 Water Treatment Design Basis Cimmaron Environmental Response Trust Sandstone A Nitrate-Nitrite Isoconcentration Map (mg/L) 800 700 600 500 400 300 200 100 0

I I Sandstone A Monitor Wells

1. Sandstone B/Alluvial Monitor Wells

= Remediation Trench Location

-l- Western Area Extraction Wells Western Area Injection Wells 0 500 1000 1500 2000

Water Treatment Design Basis 9/21/22 Cimmaron Environmental Response Trust Sandstone B, Transition Zone, and Alluvium Nitrate-Nitrite Isoconcentration Map (mg/L) 1000 1500 2000 CREATED 09/12/2022 BY BURNS & MCDONNELL ENGINEERING

9/21/22 Water Treatment Design Basis Cimmaron Environmental Response Trust Sandstone A Total Uranium Isoconcentration Map (ug/L) 800 700 600 500 400 300 200 100 0

I I Sandstone A Monitor Wells 0 Sandstone B/Alluvial Monitor Wells

=^= Remediation Trench Location

-f- Western Area Extraction Wells Western Area Injection Wells 500 1000 1500 2000

Water Treatment Design Basis 9/21/22 Cimmaron Environmental Response Trust Sandstone B, Transition Zone, and Alluvium Total Uranium Isoconcentration Map (ug/L) 323500 323000 322500 322000 321500 321000 320500 320000 500 1000 1500 2000 CREATED 09/12/2022 BY BURNS & MCDONNELL ENGINEERING

ATTACHMENT 2 Tc-99 ISOPLETH IN THE WESTERN AREA SANDSTONE A CIMARRON SITE, OKLAHOMA BURNS VvMSDONNELL. environmental properties management UC CREATE AMAZiNG.

LEGEND

-f SANDSTONE A MONITOR WELL O EXTRACTION WELL O INJECTION WELL EXTRACTION TRENCH

---

INJECTION TRENCH r - US EPA Tc-99 CONCENTRATION LIMIT OF 52.9

- J ng/L (900 pCi/L)

I I 10 ng/L (170 pCi/L)

I I 20 ng/L (340 pCi/L)

I I 30 ng/L (510 pCi/L)

I I 40 ng/L (680 pCi/L)

I I 50 ng/L (850 pCi/L)

NOTES

1. AERIAL IMAGE MOSAICKED USING GOOGLE EARTH 2017 AERIAL PHOTOS.

2. SOME CONCENTRATIONS EXCEEDED THE US EPA ACTIVITY CONCENTRATION LIMIT OF 900 pCi/L (52.9 ng/L):1346 - 95.6 ng/L.

NO CONCENTRATIONS EXCEEDED THE NRC Tc-99 ACTIVITY CONCENTRATION LIMIT OF 3,790 pCi/L (222.9 ng/L).

N 0 250 500 SCALE IN FEET NAD 1983 2011 SiateRane Oklahoma North FIPS 3501 Ft US

ATTACHMENT 2 Tc-99 ISOPLETH IN THE WESTERN AREA SANDSTONE B, TRANSITION ZONE, ALLUVIUM CIMARRON SITE, OKLAHOMA BURNS V^MSDONNELL environmental properties management. LIC CREATE AMAZING.

LEGEND ALLUVIUM MONITOR WELL

+ SANDSTONE B MONITOR WELL

+ TRANSITION ZONE MONITOR WELL O EXTRACTION WELL O INJECTION WELL EXTRACTION TRENCH

---

INJECTION TRENCH r - US EPA Tc-99 CONCENTRATION LIMIT OF 52.9

-

• ng/L (900 pCi/L) 10 ng/L (170 pCi/L) 20 ng/L (340 pCi/L) 30 ng/L (510 pCi/L) 40 ng/L (680 pCi/L) 50 ng/L (850 pCi/L) 60 ng/L (1020 pCi/L) 70 ng/L (1190 pCi/L) 80 ng/L (1360 pCi/L) 90 ng/L (1530 pCi/L)

NOTES

1. AERIAL IMAGE MOSAICKED USING GOOGLE EARTH 2017 AERIAL PHOTOS.

2. SOME CONCENTRATIONS EXCEEDED THE US EPA ACTIVITY CONCENTRATION LIMIT OF 900 pCi/L (52.9 ng/L):1346 - 95.6 ng/L.

NO CONCENTRATIONS EXCEEDED THE NRC Tc-99 ACTIVITY CONCENTRATION LIMIT OF 3,790 pCi/L (222.9 ng/L).

N 0 250 500 SCALE IN FEET NAD 1983 7011 SlatePlarK Oklahoma North FIPS 3501 FI US

- BA1 and WA Particle Tracking Results

- BA1 Remediation Component Locations TMW-24 02W43 02W45

- LA'O'lA x&W'Z 02W35 02W37 02W44 02W6Z 1410 02W36 r 02W34

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t. 02W24 02W19 02W14 02W12 02W08 iSwPiua 02W17 , 02W06 02W07 GE-BA1-02 02W0S , TMW-13 02W16

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LEGEND NOTES MONITOR WELL IN ALLUVIUM 1) Injection trench GWI-BA1-01 and extraction trench GETR-BA1-01 MONITOR WELL IN SANDSTONE B were installed in 2017.

IS MONITOR WELL IN SANDSTONE C

2) Injection well GWI-BA1-01Aand extraction wells GETR-BA1-01A MONITOR WELL IN TRANSITION ZONE FIGURE 8-2 and GETR-BA1-01B were installed in 2017.

EXTRACTION WELL/SUMP BURIAL AREA #1 GROUNDWATER INJECTION WELL 3) Isopleths are drawn based on representative uranium REMEDIATION AREAS GROUNDWATER EXTRACTION PIPING concentrations, expressed in micrograms per liter (pg/L). With a FACILITY DECOMMISSIONING PLAN ro or TREATED WATER INJECTION PIPING conservatively estimated value of 1.3% for U -235 enrichment, the REVISION 3 Q ID 0 LD 02 GROUNDWATER EXTRACTION TRENCH 201 pg/L isopleth, as shown, represents the 180 pCi/L (picocuries TREATED WATER INJECTION TRENCH per liter) isopleth.

^BURNS CO O o2 201 ug/L URANIUM ISOPLETH xVMSDONNELL. environmental

£= I 4) Basemap: Google Earth 2017 properties management. ILC 0 LD REMEDIATION FACILITY O. 22 o BA1-A REMEDIATION AREA Q Rev No: 0 BA1-B REMEDIATION AREA SUBAREAS Preparer: TJKIMMEL Date: 9/14/2022 PROPOSED LICENSED AREA 100 200 IS Reviewer: EDULLE Date: 9/14/2022

.1 m RADIOLOGICALLY CONTROLLED AREA O csi Coordinate System cO SCALE IN FEET NAD 1983 StatePlane Oklahoma North FIPS 3501 Feet N CM