ML22273A083
| ML22273A083 | |
| Person / Time | |
|---|---|
| Site: | 07000925 |
| Issue date: | 09/22/2022 |
| From: | Nardi A Enercon Services, Environmental Properties Management |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards |
| References | |
| Download: ML22273A083 (35) | |
Text
Environmental Property Management, LLC
Cimarron Decommissioning Project
Determination of Conservative U-235 Enrichment Levels for Treatment Trainsat Cimarron Site
Technical Memorandum
Enercon Services, Inc.
September 22, 2022
Revision 1
Prepared by:
A. Joseph Nardi
Reviewed by:
Charles Beatty
Approved by:
Dane Watson
September 22, 2022 Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site
Revision Record
Date Revision Comment
September 9, 2022 0 Initial Issue
September 22, 2022 1 Correction to headers on Table 8.1 and editorial changes
September 22, 2022 Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site
TABLE OF CONTENTS
1.0 PURPOSE....................................................................................................................................... 1 2.0 EXECUTIVE
SUMMARY
.............................................................................................................. 2 3.0 DISCUSSION.................................................................................................................................. 3 4.0 METHODOLOGY........................................................................................................................... 4 5.0 ASSUMPTIONS............................................................................................................................. 5 6.0 INPUT............................................................................................................................................... 6 6.1 Identification of Groundwater Wells......................................................................................... 6 6.2 Data Set Compilation and Screening...................................................................................... 6 6.3 Complete Data Set..................................................................................................................... 7 6.4 Extraction Well Flow Rates....................................................................................................... 7 7.0 CALCULATIONS............................................................................................................................ 8 7.1 Consideration of U-234 Mass................................................................................................... 8 7.2 Calculation of Enrichment......................................................................................................... 8 7.3 Determination of Propagated Uncertainty for Calculation of Enrichment Level............... 9 8.0 RESULTS...................................................................................................................................... 10
9.0 CONCLUSION
S........................................................................................................................... 11 APPENDIX A
September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 1
1.0 PURPOSE
The purpose of this technical memorandum is to establish conservative uranium enrichment levels (% U-235) in groundwater Extraction Wells for the Cimarron Decommissioning project.
The site is located 1/2-mile North of the Highway 33 and Highway 74 junction near Crescent, Oklahoma. Concentrations of uranium in groundwater were analyzed by utilizing the inductively coupled plasma mass spectrometry (ICP-MS). Measurement data utilized in this analysis was collected during the period of 2018 through the first quarter of 2022. These conservative estimates of expected uranium enrichment values for each of the two treatment trains will be used for the following purposes:
- 1. Project the anticipated U -235 loading of the resin columns as a function of time in order to compare the total U-235 possession against the license limit, and
- 2. Provide an initial U -235 enrichment value for each train as the basis for input to the Material Control and Accounting (MCA) program until actual values are measured.
1 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 2
2.0 EXECUTIVE S UMMARY
The maximum conservative ur ani um enri chment percentage expected for the site was calculated at the 95% conf iden ce level (CL). The calculation used t he average cal cu lated enr ichment plus the average pr opagated un certainty of the laboratory analysis of recent data.
The data set used in this analysis is based on measurements made by the ICP -MS (EPA 200.8) method for groundwater samples collected from January 2018 through the first quarter of 2022.
This method has been selected as the preferred analytical method for the analysis of both liquid and solid samples for the project.
Using the measurement data from the ICP-MS method during the period considered, the maximum conservative % U-235 enrichment (at the 95% C L) for the site is 1.30 % for the treatment train from the Burial Area 1 (BA1) area and 2.75% for the treatment train from the Western Alluvial Area (WAA).
2 September 22, 2022
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3.0 DISCUSSION
The areas of the Cimarron site, based on groundwater data, exhibit different levels of urani um concentration and enri chment. Groundwater from t wo separate well field areas will be processed as described below.
- 1. WAA - Will collect groundwater from a portion of the WAA where the uranium concentrations are greater than the Derived Concentration Guideline Level ( DCGL) for release. This area exhibits the highest enrichment levels for the uranium. The contamination source for this area is from early process wastewater that was flowing through a process drain line in this area.
- 2. BA1 - Will collect groundwater from the area designated as BA1. The contamination source in this area was the waste material that was placed in trenches. This area exhibits the highest uranium concentrations but a low enrichment level.
Groundwater from each of the se two areas represents different contamination sources that will be processed through separate groundwater treatment trains. As groundwater is extracted from each area, inflow of surrounding natural groundwater containing natural uranium will begin lowering the average uranium concentration and enrichment level for each of the trains.
It is expected that the uranium concentratio n and enrichment levels that are encountered at the initial startup will continually decrease with time. Therefore, t he enrichment level that is derived in this analysis is expected to be the maximum conservative value and will be used as the initial worst-case basis.
3 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 4
4.0 METHODOLOGY
The process for det ermination of the conservative maximum enrichment value for the ur anium in the groundwater is to measure the uranium concentration (micrograms per liter) of the U-235 and U-238 and assi gn a conse rvative en richment value, at the 95% CL, based on the uncertainty of the measurements.
- 1. The data utilized for this evaluation are all the data obtained during the period of January 2018 through the first q uarter of 2022 and analyzed by the ICP-MS method.
Measurements that were marked with a qualifier (for either the U-235 or U-238) are not included.
- 2. The analytical determination of enrichment has been based on ICP -MS measurements of two uranium isotopes (U-235 and U-238). Each measurement has an associated uncertainty for the calculated enrichment value. To evaluate the uncertainty associated with the calculated enrichment based on the ICP-MS results for each uranium isotope, the propagated uncertainty has been calculated. The equation used to calculate the propagated uncertainty is presented in Section 7.0. The conservative maximum enrichment is calculated as the enrichment at the 95% CL.
- 3. For each planned Extraction Well location, the groundwater sample data for wells in the near vicinity of the Extraction Well were used to provide the data for the U-238 and U-235 mass concentration, and therefore the U-235 enrichment level, for that Extraction Well.
- 4. There are two treatment trains planned and both will be process ed at one groundwater facility, the Western Area Treatment Facility (WATF). The two groundwater trains are from the BA1 area of the site and the WAA area of the site. Each Extraction Well will contribute a portion of the total flow to its designated treatment train. The average enrichment for each treatment train is calculated as the weighted average (based on the contribution to the total flow) of all the Extraction Wells feeding that train.
4 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 5
5.0 ASSUMPTIONS
It is assumed that the selected wells identified in Section 6.1 provide groundwater composition that is representative of the groundwater that will be extracted from the Extraction Well.
5 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 6
6.0 INPUT
6.1 Identification of Groundwater Wells Table 6.1 identifies the groundwater wells that were used to provide the measurement data for wells in the near vicinity of each planned Extraction Well. This was used to provide the data for the U-238 and U-235 mass concentration, and therefore the U-235 enrichment level, for that Extraction Well. The location of these wells is provided on drawings in the Decommissioning Plan and is not repeated here.
Table 6.1 - Identification of Groundwater Wells U sed to E stimate U-235 Enrichment for Extraction Wells BA1 AREA GE-BA1-02 GE-BA1-03 GE-BA1-04 GE-BA1-05 02W32 02W14 02W37 1361 TMW13 02W19 02W43 1363 02W07 02W18 02W44 02W08 GE-BA1-06 GETR-BA1-01A GETR-BA1-01B GETR-BA1-02A TMW24 1405 02W02 02W01 1365 02W28 1404 WAA AREA (see Note)
GE-WAA-02 GE-WAA-03 GE-WAA-04 GE-WAA-05 T-66 T-62 T-79 T-68 GETR-WU-01A T-67 T-65 T-68 T-69 MWWA-03 T-76 T-72 MWWA-09 T-77 Note: Highlight indicates there were no sample results for this well.
6.2 Data Set Compilation and Screening To complete this analysis, a com plete set of ICP-MS data was compiled for the period of January 2018 through the first quarter of 2022 sampling events. Samples that had a qualifier were not included in the evaluation. The results for all wells identified in Table 6.1 were included in the data set. As noted in Section 4.0, the relative uncertainty for the reported U-235 and U-238 results was based on the reported uncertainty.
6 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 7
6.3 Complete Data Set Appendix A provides the laboratory data for all the samples analyzed by the ICP-MS method that is used in this analysis. Only that sample data which had a qualifier for either the U-235 or U-238 reported result were excluded from the evaluation.
6.4 Extraction Well Flow Rates The flowrates for the Extraction Wells used in Table 8.1 were provided by Burns & McDonnell on a flow analysis model for the well fields.
7 September 22, 2022
Determination of Conservative U-235 Enrichment Level for Rev. 1 Treatment Trains at Cimarron Site Page No. 8
7.0 CALCULATIONS
7.1 Consideration of U-234 Mass The ca lcu lation of the uranium enri chment is based on the measured concentration of the two uranium isotopes of interest (U-235 and U -238). The measured concentrations are in units of mass (micrograms per liter). Even thoug h the U-234 con tribut es over half of the ac tivity for each sa mple, when conv erted to mass equi valents, the U-234 cont ribut es on average onl y 0.01 3% of the total urani um mass. Therefore, the contribution of the U-234 to the total mass and the propaga ted unc ertainty in the cal culated enr ichment of the ur anium in the sa mple was not considered (Table 7.1).
Table 7.1 - Contribution of U-234 to Activity and Mass of Enriched Uranium
Enrichment
(% U-235 Percent of Total Activity Percent of Total Mass by mass) U-234 U-235 U-238 U-234 U-235 U-238 0.711 48.1% 2.3% 49.7% 0.005% 0.711% 99.3%
1 54.8% 2.8% 42.5% 0.007% 1% 99%
2 68.3% 3.7% 28.1% 0.013% 2% 98%
3 75.1% 4.1% 20.8% 0.019% 3% 97%
5 82.1% 4.5% 13.4% 0.031% 5% 95%
7.2 Calculation of Enrichment The enrichment of the uranium is ca lcu lated (ignoring the U-234 cont ribut ion) by:
E = MU235 / (MU235 + MU238)
Wher e:
E = t he uranium enr ichment level in weight % U-235 Mi = the mass of the iso tope in micrograms iso tope per liter of sa mple
8 September 22, 2022
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7.3 Determination of Propagated Uncertainty for Calculation of Enrichment Level The reported mass conce ntration for each iso tope has an asso ciated measurement unc ertainty reported at the 2 si gma (95% CL) level. To accurately asse ss the uncer tainty for the calcu lated enr ichment value asso ciated with the sa mple, the propag ated uncertainty was ca lcu lated as follows:
E 2= [MU235 / (MU235 +MU238)] 2 x {(U235/MU235) 2 + [(U2352 + U2382) / (MU235 + MU238)2]}
Where:
E = ca lculated propagated uncertainty for enrichment value at the 95% CL;
Mi = the mass of the iso tope in micrograms iso tope per liter of sa mple, and
i = measurement uncertainty for mass co ncentration of isotope (Mi).
9 September 22, 2022
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8.0 RESULTS
Conservative initial urani um enri chment values expected for all Extraction Wells were calculated as a weighted average based on the percentage of the total flow to the treatment train. The flow rates are based on the latest flow model prepared for the revised Decommissioning Plan. In this revision, certain wells were not used.
Table 8.1 - Conservative Enrichment of Feed to the Two Treatment Trains
Source - BA1 Area Conservative Flow Rate Flow Contribution Weighted Extraction Well Maximum (gpm) Contribution to Total Conservative
% U-235 Enrichment Enrichment GE-BA1-02 1.26% 31 31.0% 0.39%
GE-BA1-03 1.32% 24 24.0% 0.32%
GE-BA1-04 1.31% 31 31.0% 0.41%
GE-BA1-05 1.27% 0.0% 0.00% 1.30%
GE-BA1-06 1.29% 0.0% 0.00%
GETR-BA1-01A 1.30% 0.0% 0.00%
GETR-BA1-01B 1.26% 7 7.0% 0.09%
GETR-BA1-02A 1.37% 7 7.0% 0.10%
Source - WAA Area Conservative Flow Rate Flow Contribution Weighted Extraction Well Maximum (gpm) Contribution to Total Conservative
% U-235 Enrichment Enrichment GE-WAA-02 2.05% 30 28.0% 0.58%
GE-WAA-03 2.11% 24 22.4% 0.47%
GE-WAA-04 3.88% 20 18.7% 0.73% 2.75%
GE-WAA-05 3.27% 25 23.4% 0.76%
GETR-WU-01A 2.89% 8 7.5% 0.22%
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9.0 CONCLUSION
S
The initial cons ervative value for the U-235 enri chments for the two treatment trains has been determined to be 1.30% U -235 (BA1) and 2.75% U-235(WAA).
11 APPEN DIX A Sample Analysis Results Used in this Evaluation (By ICP-MS Method for Period of January 2018 through the First Quarter of 2022 )