DRC-2024-004817

March 8, 2024
Vern C. Rogers, Director of Regulatory Affairs
EnergySolutions, LLC
299 South Main Street, Suite 1700
Salt Lake City, UT 84111
RE:Federal Cell Facility Application Request for Information
Dear Mr. Rogers:
The Division of Waste Management and Radiation Control (Division) hereby provides follow up Requests for Information (RFI) regarding the Federal Cell Facility Application dated August
4, 2022.
Each RFI in the attached document represents a follow up to an RFI issued earlier in the application review process. The numbering system ties the additional questions to the initial
RFI with an added letter designation. When responding to an RFI, please use the assigned number representing the question.
With this round of follow up RFIs, the Division recommends that appropriate staff from the Licensee, the Division and consultants meet to discuss each matter for clarity. Please contact
Otis Willoughby at 385-622-2213 to schedule ameeting.
Sincerely,
Douglas J. Hansen, Director
Division of Waste Management and Radiation Control
DJH/OHW/JMK
Enclosure:Federal Cell Application, Requests for Information.
c:Jeff Coombs, EHS, Health Officer, Tooele County Health Department
Bryan Slade, Environmental Health Director, Tooele County Health Department EnergySolutions General Correspondence EmailLLRW General Correspondence Email
Federal Cell Application Review
Request for Information or Updates to the Application (RFI)
General
Each of the RFI’s has been assigned an identifier with a numbering convention as follows-
Application/Appendix Section
Section/Appendix Subsection
Section/Appendix Subsubsection (when applicable)
Sequential numbering
Example: A question in Section 1, subsection 1, subsubsection 1 -The first RFI # would be 1.1.1-1, the next question in that section/subsection would be numbered 1.1.1-2
Please refer to the assigned RFI number when submitting a response.
Appendix O:
SIBERIA Modeling
0-38.a
The long-term stability of the Federal Cell Facility (FCF) and the requirement for ongoing maintenance after closure must be based upon analyses of active natural processes. The analyses
must provide reasonable assurance for long-term stability of the FCF, and that upon closure of the FCF (10 CFR Part 61.13), ongoing active maintenance will not be necessary.
Questions remain regarding the use of SIBERIA as a tool to evaluate the long-term stability/erosion of the FCF. The processes leading to rill-gully channelization of landforms are stochastic
and driven by threshold precipitation events at the Clive site.
The SIBERIA model for the FCF uses the same precipitation magnitude in each time step, yet gullying is a threshold dominated event driven by particularly large storm events. It appears
to the Division that the SIBERIA model is not incorporating the stochastic-threshold processes needed to begin rill-gully formation and not channelization and may lack the resolution
to capture these events. As for calibration of the SIBERIA model, the RHEM model itself does not seem to result in significant channeling, gullying or headward erosion, and using a RHEM
model to calibrate a SIBERIA model could lead to a poorly calibrated model and does not give realistic results. The calibration of the model by matching sediment flux also does not capture
the spatial/temporal distribution of erosion that is important to the long-term stability of the FCF. The approach of Tucker (Tucker 2004) using a divergence of the sediment flux might
provide a more realistic model.
Given the concerns with gullying, the Division requests that EnergySolutions either modify the SIBERIA model to account for stochastic precipitation or develop an updated model that
can address the concerns outlined.