DRC-2025-000625

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Div of Waste ManegemeAt
and Radiation Control
FEB 2 1 2025
--------ENERGYSOLUTIONS --------
February 21, 2025 CD-2025-037
Mr. Doug Hansen, Director
Division of Waste Management and Radiation Control
P.O. Box 144880
Salt Lake City, UT 84114-4880
Subject: Federal Cell Facility Application: Responses to the Director's Requests for Information
DRC-2024-005704, DRC-2024-006532, and DRC-2024-006804
Dear Mr. Hansen,
Energy Solutions hereby responds to the Utah Division of Waste Management and Radiation Control's
May 31, 2024 (DRC-2024-005704), August 13, 2024 (DRC-2024-006532), and September 16, 2024
(DRC-2024-006804) Requests for Information (RFI) on our Federal Cell Facility Application. A response
is provided for each request using the Director's assigned reference number.
Each RFI letter is addressed individually, with the text of the RFI quoted in bold italics followed by its
response. Multiple follow-up RFI letters are addressed in this response, with each letter preceded by a
solid line.
The following attachments are electronically provided on the attached compact disc:
1. Radioactive Waste Inventory for the Clive DU PA (Neptune 2025)
• Neptune and Company "Radioactive Waste Inventory for the Clive DU PA Clive DU PA
Model v4.0" (NAC-0023_R7) Technical Report, February 14, 2025.
• Location: CD:\REFERENCES\Waste Inventory v4.0.pdf
2. Clive Operational Period RESRAD Analysis supporting electronic files.
• Neptune and Company "RESRAD Input and Output Electronic Files.
■ Input Location: CD:\RESRAD\ *.ROF
• Output Location: CD: \RESRAD\ *.REP
3. As-Built drawing (0009-0l(E) Pipe Repair AS-BUILT.pd/) of the evaporation storage pond
■ EnergySolutions "2000 LARW Evaporation Pond." (Engineering Drawing 0009-01, Rev E.
February 22, 2008.
• Location: CD:\REFERENCES\0009-0l(E) Pipe Repair AS-BUILT.pd/
4. Workbook "DU waste cones and RESRAD results"
• Neptune. "DU waste cones and RESRAD results-Feb 2025.xlsx", February 2025.
■ Location: CD:\REFERENCES\ DU waste cones and RESRAD results-Feb 2025.xls
5. Portsmouth Oxide Sampling Lab Results
■ DUF6 Project, 2023a. Engineering Notice, Portsmouth Oxide Sampling Lab Results from
External Lab, Southwest Research institute (SwRI}, EN-23-X-CON-008, Rev. 1, Depleted
Uranium Hexafluoride Conversion Project, 2023
• Location: CD: \REFERENCES\DUF6 Project 2023a.pdf
299 South Main Street, Suite 1700 • Salt Lake City, Utah 84111
(80 I) 649-2000 • Fax: [phone] • www.energysolutions.com
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ENERGYSOLUTIONS
6. Paducah Oxide Sampling Lab Results
Mr. Doug Hansen
CD-2025-037
February 21 , 2025
• DUF6 Project, 2023b. Engineering Notice, Paducah Oxide Sampling Lab Results from
External Lab, Southwest Research Institute (SwRJ), EN-23-C-CON-007, Rev. 1, Depleted
Uranium Hexafluoride Conversion Project, 2023
• Location: CD:\REFERENCES\DUF6 Project 2023b.pdf
7. Clive Operational Period RESRAD Analysis R3
• Neptune, "Clive Operational Period RESRAD Analysis -Operational Period Modeling of
Depleted Uranium Radionuclide Concentrations in Groundwater, Pond Water, Pond Biota,
and Air, and Modeling of Radon Ground Surface Flux -Revision 3 ", February 2025
• Location: CD:\REFERENCES\Clive Operational Period RESRAD Analysis R3 Feb 2025.pdf
8. Strategy for Characterizing Transuranics and Technetium Contamination in Depleted UF6
Cylinders
• Hightower, J.R., et al., 2000. Strategy f or Characterizing Transuranics and Technetium
Contamination in Depleted UF6 Cylinders, ORNLITM-2000/242, Oak Ridge National
Laboratory, Oak Ridge TN, October 2000
• Location: CD:\REFERENCES\Hightower et al 2000.pdf
Appendix AB:
Operational Period Modeling
■ AB-7.a: (from DRC-2024-005704): In the previous version of Appendix AB, it does not appear that
the radionuclide inventory was time averaged, but in this most recent version provided,
EnergySolutions changed the approach to time averaging. Please provide clarification as to why the
approach has changed.
The RESRAD-OFFSITE model requires that the volume of the contaminated zone be constant.
The operational period analysis incorporates the simplifying assumption that the time-averaged
concentrations of disposed radionuclides in the contaminated zone during the emplacement
period are one-half of the waste concentrations. Practically, this has the effect of overestimating
potential releases in the first half of the operating period.
■ AB-7.b: (from DRC-2024-005704): The revised Appendix AB states that the inventory used in the
December 2023 RESRAD model was derived from the DU PA v2.0 GoldSim model. However, the
most recent version of the GoldSim model v3.0 appears to have had changes to the assumed
radionuclide inventory. Any changes made to the assumed radionuclide inventory in the DU PA
v3.0 model should also be reflected in the RESRAD model. Please update the model accordingly.
The RESRAD model has been updated to reflect the inventory that will be used in the DU PA
v4.0 GoldSim model. This includes isotopic uranium distributions developed for the GDP waste
in response to RFI O-29.a.
299 South Main Street, Suite 1700 • Salt Lake City, Utah 84111
[phone] • Fax: [phone] • www.energysolutions.com
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ENERGYSOLUTIONS
Mr. Doug Hansen
CD-2025-03 7
February 21 , 2025
• AB-7.c: (from DRC-2024-005704): The Division was unable to reproduce the concentrations used in
the revised RESRAD model. Please provide additional information as to how these concentrations
were calculated.
The derivation of concentrations input to the RESRAD model is provided in the supporting
documents workbook "DU waste cones and RESRAD results-Feb 2025.xlsx" on the tab
"Inventory Conv." While preparing the revised documents, the technical team found an error in
the conversion from Bq to Bq/g. This error has been corrected.
• AB-10.a: (from DRC-2024-005704): The Division reviewed Ground Water Quality Discharge Permit
No. UGW450005 as well as Engineering Drawing 0801-G0J but was unable to locate the dimensions
of the 2000 storm water retention pond to confirm the dimensions used in the RESRAD model. The
dimensions of this surface water body in RESRAD were JOO meters by 105 meters; however, it
appears to be more rectangular in shape upon review of the 2000 storm water retention pond in
Engineering Drawing 0801-G03. Please provide the engineering drawing, with dimensions, that was
used to determine the dimensions of the pond used in RESRAD.
The As-Built drawing (0009-0l(E) Pipe Repair AS-BUILT.pdt) of the evaporation storage pond
is provided in the supporting documents folder. The RESRAD model has been updated to
correlate with the As-Built dimensions.
• AB-23.a: (from DRC-2024-005704): In consideration of RFI AB-7.a and AB-7.b, please reevaluate
the most current RESRAD model and determine if a new run of the RESRAD model is required.
The RESRAD model has been updated and rerun to reflect the changes di scussed in the preceding
comments. Electronic supporting files are included as well.
• 0-29.a: (from DRC-2024-006532): The response to RFI 0-29 did not address the main concern of
whether the uranium isotopic composition in the Savannah River Site (SRS) Depleted Uranium (DU)
accurately reflects the uranium isotopic composition in pure Gaseous Diffusion Plant (GDP) DU.
The SRS receives pure GDP DU and creates targets out of it by exposing the GDP DU to a neutron
flux from within a reactor to create plutonium. The neutrons turn some of the U-238 into plutonium
through activation and beta decay. The initial U-238/U-235/U-234 composition of the targets is the
same as the GDP DU composition. It can also be observed that, based on the presence of fission
products in the SRS DU, the neutrons also cause some fission in the target DU. What is not known,
however, is what fraction of fission was due to U-238 and plutonium, versus U-235. Because the
GDP DU has less U-235, there is reason to believe that there is not a large fraction of U-235
fissioning. Moreover, there may be other neutron induced uranium transformations happening while
the targets are in the reactor. Therefore, it may be concluded that the U-238/U-235/U-234
composition of the targets coming out of the SRS reactors is different from the GDP DU
composition. However, we do not know by how much the two compositions differ.
299 South Main Street, Suite 1700 • Salt Lake City, Utah 84111
[phone] • Fax: [phone] • www.energysolutions.com
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ENERGYSOLUTIONS
Mr. Doug Hansen
CD-2025-03 7
February 21 , 2025
Please demonstrate (within some calculated uncertainty) that the change in the U-238/U-235/U-234
composition is insignificant.
Additional data has been obtained to represent the GDP DU (DUF6 Project 2023a, 2023b). New
input probability distributions have been developed to represent the activity concentrations of
uranium isotopes contained in the GDP DUF6 waste. NAC-0023_R7, Radioactive Waste
Inventory for the Clive DU PA has been revised to document the data and distribution
development for isotopes of uranium associated with the GDP DU. The DU PA will be revised to
v4 .0 once all round 2 RFI responses are complete so that GDP and SRS DU each have their own
U-238/U-235/U-234 distributions.
• 0-25.a: (from DRC-2024-006804): The response discusses the increased uncertainty associated with
using the concentration values listed in table 2 of Hightower et al. (2000) as bounding values. Please
quantify the uncertainty that would be introduced to this analysis by subjecting the maximum
concentrations values listed in table 2 of Hightower et al. (2000) to ratio statistics.
The ratio of 4.55 pCi/g for Am-241 and 270.3 pCi/g for Tc-99 from Table 2 in Hightower (2000)
is about 60; i.e., 1 part Am-241 for every 60 parts Tc-99. We assume the intent is to apply that
ratio to the Tc-99 concentration in the DU PA model. The mean Tc-99 concentration in the model
is about 40,000 pCi/g. Using the ratio of 60 would imply an Am-241 concentration of
approximately 660 pCi/g (compared with the modeled mean of 14.2 pCi/g Am-241). Running the
model deterministically with 660 pCi/g activity concentration of Am-241 produces a dose of zero
across the 10,000 year compliance period, and a groundwater concentration for Am-241 of zero.
The reasons for this are that the DU waste is disposed below grade. The K,i for Am-241 is about
300 in which case partitioning into water is almost non-existent, which means that the pathways
involving transport to groundwater and diffusion are effectively non-existent for Am-241 in these
time frames . In addition, plant roots have a maximum depth of 580 cm, and animal burrows are
more shallow, in which case biota do not access the waste directly. Consequently, there is no
pathway by which Am-241 can move to the accessible environment in the DU PA model.
References:
DUF6 Project, 2023a. Engineering Notice, Portsmouth Oxide Sampling Lab Results from External Lab,
Southwest Research Institute (SwRI), EN-23-X-CON-008, Rev. 1, Depleted Uranium Hexafluoride
Conversion Project, 2023
DUF6 Project, 2023b. Engineering Notice, Paducah Oxide Sampling Lab Results from External Lab,
Southwest Research Institute (SwRI), EN-23-C-CON-007, Rev. 1, Depleted Uranium Hexafluoride
Conversion Project, 2023
Hightower, J.R., et al., 2000. Strategy for Characterizing Transuranics and Technetium Contamination in
Depleted UF6 Cylinders, ORNL/TM-2000/242, Oak Ridge National Laboratory, Oak Ridge TN, October
2000
299 South Main Street, Suite 1700 • Salt Lake City, Utah 84111
(801 ) 649-2000 • Fax: [phone] • www.energysolutions.com
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ENERGY SOLUTIONS
Mr. Doug Hansen
CD-2025-037
February 21 , 2025
If you have further questions regarding these responses to the director's requests of DRC-2024-005704,
DRC-2024-006532, and DRC-2024-006804, please contact me at (801 ) 649-2000.
Sincerely,
Vern C.
Rogers
Vern C. Rogers
Digitally signed by Vern C. Rogers
ON: cn=Vern C. Rogers, o=EnergySolutions,
ou=Waste Management Division,
email=[e-mail], c=US
Datec 2025.02.21 1356,08-07'00"
Director, Regulatory Affairs
enclosure
1 certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system
designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons
who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my
knowledge and belief. true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the
possibility of fine and imprisonment for knowing violations.
299 South Main Street, Suite 1700 • Salt Lake City, Utah 84111
[phone] • Fax: [phone] • www.energysolutions.com
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