Depleted Uranium Performance Assessment Chronology:

Update April 16, 2021

The DU PA has been incorporated with the Federal Cell License Application. See the Federal Cell License Application page.

Update March 16, 2020

Phase 1 Basal Aquifer Study

Update January 20, 2020

Draft Radioactive Material License Application for the Federal Cell Facility

Update December 19, 2019

Federal Cell Facility Pre-Filing Process

Update July 25, 2019

Status of Interrogatories, July 2019

Update April 3, 2018

EnergySolutions Responses to Interrogatories Raised with Version 1.4 of the DU PA Model

Update May 11, 2017

Interrogatories re: Depleted Uranium Performance Assessment, Model version 1.4

Update: December 6, 2016

Review of the DU PA , model version 1.4, will continue on January 1, 2017, at a higher priority.

Update: February 5, 2016

Review of the DU PA will continue but at a lower priority. DEQ comments on Version 1.4 of the model will be delayed beyond April 30th

Update: December 1, 2015

EnergySolutions submitted the following documents to DEQ in response to issues raised in the April 2015 Draft Safety Evaluation Report (SER). The documents provide general comments on the content and scope of the SER, specific technical comments and edits to the SER, and Version 1.4 of the DU PA Clive modeling report.

Update: May 6, 2015

Public information meetings will be held today and tomorrow in Tooele and Salt Lake City. PDF versions of the eight posters that will be available at the meetings are provided below for reference. Meetings at both locations will be held from 5:00 to 8:00 pm.

Update: April 16, 2015

DEQ has granted EnergySolutions’ request to delay public comment on the Safety Evaluation Report (SER) to give the company more time to to address issues that were not resolved in the report and provide the public with an opportunity to comment on a fuller record containing this additional information. The public comment period for the SER will be placed on hold for a limited time.

For the purposes of the SER, “resolved” means that a determination has been made that there is sufficient information to demonstrate that this requirement will be met.

The agency will hold two public informational meetings on the current SER on May 6, 2015, and May 7, 2015, to provide the public with the opportunity to ask questions and discuss SER findings with DEQ staff and representatives from its outside consultant, SC&A.

DEQ will schedule another public comment period at a later date. The agency will hold public hearings during this comment period to accept oral comments. Additional public information meetings may be held, as appropriate, at the time of any final proposal.

Comments submitted during the comment period that began April 13, 2015, will become part of the formal record. The comment period, however, is now suspended, and any further comments will not be a part of the record.

Update: April 14, 2015

EnergySolutions has requested that the public comment period for the Depleted Uranium Performance Assessment (DU PA) be placed on hold until the company has an opportunity to address questions raised in the Safety Evaluation Report (SER).

Update: April 13, 2015

Notice of Public Comment and Safety Evaluation Report

The Director of the Division of Radiation Control is requesting public comment on the Safety Evaluation Report (SER) for the Depleted Uranium Performance Assessment (DUPA).

Update: March 12, 2015

DEQ Response To Final Submittals and Changes to Begin of Public Comment Period.

Update: March 11, 2015

EnergySolutions submitted the following supplementary documents and studies in response to DEQ’s requests for additional information.

Update: December 10, 2014

Electronic erosion modeling files to Appendix 10(I) and 10 (II) of the DU PA Compliance Report Ver.2, July 11.

Update: November 24, 2014

DEQ has approved EnergySolution request for a three month extension. Public comment period now scheduled to begin April 6, 2015.

Update: November 21, 2014

EnergySolution is asking for a three month extension request in order to complete a dune soil layer gradation study.

Update: September 8, 2014

Public Comment Period now scheduled to begin January 12, 2015.

Update: September 2, 2014

EnergySolutions is asking for a 2-month extension before going out for public comment

Update: August 21, 2014

DEQ Critique of Supplemental Deep Time Analysis

Update: August 19, 2014

Supplemental Interrogatories concerning the Evapotranspirative Cover Design and Infiltration Rates

Update: August 6, 2014

Supplemental analysis for the deep time component of the Clive DU PA model v1.2.

These following three files were updated (table results and the executive summary) because of the supplemental deep time analysis.

Update: July 11, 2014

Revision 2 of the Report, “Utah Low-Level Radioactive Waste Disposal License (RML UT2300249) Condition 35 Compliance Report,” which includes responses to the Round 3 Interrogatories (as Appendix E) and responses to all other prior Interrogatories. As an aid to the reviewers, attached are redline-strikeout versions of Appendix A and those appendices that have changed since they were last submitted. This is the final submittal from EnergySolutions before the public comment period starts in September 2014.


Rule R313-25 was modified on April 3, 2014; a new provision regarding time frames for licensing actions was added as R313-25-6. The provision previously numbered R313-25-6 was renumbered R313-25-7 and the following provisions through R313-25-28 were similarly renumbered. Most significantly, the provision referred to in these documents below as R313-25-8 is found in current rules as R313-25-9.

Update: July 1, 2014

Round 3 Interrogatories of the Depleted Uranium Performance Assessment. These Interrogatories pertain mostly to a critique regarding version 1.2 of the model (see June 6, 2014).

Update: June 25, 2014

References mentioned in the Interrogatories and the reports provided below, including the Clive DU PA Model Version 1.2.

Update: June 17, 2014

EnergySolutions’ responses to the Round 2 Interrogatories.

Update June 6, 2014

EnergySolutions revision of the initial design of its Federal Cell to include an evapotranspirative cover equivalent to that currently under review for the Class A West Embankment.

As a result, EnergySolutions is re-submitting Appendix A of its Condition 35 Compliance Report, which now considers the impacts of the evapotranspiration cover in version 1.2 of the depleted uranium Performance Assessment GoldSim model.

Update May 27, 2014

Round 2 Interrogatories of the Depleted Uranium Performance Assessment

Update: April 1, 2014

EnergySolutions responses without modeling for the evapotranspiration cover.

Update: February 28, 2014

Round 1 Interrogatories of the Depleted Uranium Performance Assessment Based on the scope of the interrogatories, probabilistic model is in order.

Update: December 11, 2013

DEQ’s response regarding clarification of completeness comments and inclusion of new material in Energy Solutions November 8 reply. Preliminary Completeness Review, DRC Radioactive Material License UT 2300249.

Update: November 13, 2013

DEQ open house on the performance assessment.

EnergySolutions response to the DEQ completeness review comments. The facility responded to all comments deemed deficient regarding the completeness of the compliance report. EnergySolutions proposes to respond to the regulatory and technical inadequacies of the modeling portion of the performance assessment in the Round 1 interrogatory phase.

Update: October 2013

Preliminary completeness review of the depleted uranium performance assessment.

Update: August 2013

DEQ hired an outside contractor, S. Cohen & Associates (SC&A) from Virginia to evaluate this Performance Assessment to determine if it is adequate and addresses the necessary requirements. The results of this review and subsequent responses by EnergySolutions will be used by the Director of DRC to make a determination whether or not to issue a license amendment allowing significant quantities of concentrated DU to be disposed at the EnergySolutions facility.

Update June 1, 2011

EnergySolutions submits a Performance Assessment (PA) for the disposal of significant quantities of concentrated depleted uranium (DU) at their facility in Clive, Utah. The PA is a site-specific evaluation to determine whether there is reasonable assurance of compliance with regulatory performance objectives and in identifying critical data, facility design, and modeling procedures, to determine if DU can be safely managed at the EnergySolutions facility.

Performance Assessment

This document is divided into its basic components for easier download and review. The content descriptions were prepared by DEQ staff as a brief guide for the user.

  • Complete Report
    Contains the full performance assessment with bookmarks.
  • Compliance Report
    A review by EnergySolutions of applicable rules to demonstrate compliance with the requirements.
  • Final Report for the Clive DU PA Model (Version 1.0)
    The main probabilistic model report, performed with GoldSim. This report contains the findings of risks associated with the potential disposal of DU at EnergySolutions’ Clive facility.
  • Appendix 1—FEP Analysis
    Analysis for the features, events, and process (FEP) to determine whether the EnergySolutions disposal location and containment technologies are suitable for protection of human health.
  • Appendix 2—Site Model
    The conceptual site model for significant quantities of concentrated DU disposal at EnergySolutions.
  • Appendix 3—Embankment Modeling
    Addresses specific details relating to the options for significant quantities of concentrated DU disposal in the Class A South disposal cell at EnergySolutions.
  • Appendix 4—Waste Inventory
    An inventory of the proposed waste streams and isotopes for DU disposal that were used in the modeling.
  • Appendix 5—Unsaturated Zone Modeling
    The parameters used in the modeling to determine how the constituents might migrate through the soil.
  • Appendix 6—Geochemical Modeling
    The geochemistry of the site used in the modeling.
  • Appendix 7—Saturated Zone Modeling
    The groundwater parameters used in the modeling to determine how long, if ever, it would take for radionuclides to enter the groundwater.
  • Appendix 8—Air Modeling
    The atmospheric parameters used in the modeling to determine radionuclides that might be wind derived in the breathing zone around the disposal cell.
  • Appendix 9—Biological Modeling
    The parameters used in the biotic transport modeling to determine how insects and plants might transport radionuclides from the disposal cell.
  • Appendix 10—Erosion Modeling
    The parameters used to determine how radionuclides might be transported from disposal cell through erosion events like gullies developing in the cell.
  • Appendix 11—Dose Assessment
    The parameters used in the modeling to determine the dose rate that individuals, such as ranchers, hunters, off road vehicle enthusiasts, might be exposed when near the disposal cell.
  • Appendix 12—Decision Analysis
    An analysis to determine whether the location and containment technologies used by EnergySolutions are suitable for protection of human health.
  • Appendix 13—Deep Time Assessment
    The parameters used in the modeling to estimate what might happen at the site over many thousands of years.
  • Appendix 14—Development of Probability Distributions
    The rationale used for the probabilistic behavior associated with the input parameters and a discussion of some uncertainties in the modeling.
  • Appendix 15—Sensitivity Analysis
    The rationale for reducing the uncertainties in the modeling.
  • Appendix 16—GoldSim Parameters
    The collection of the input parameters used in the DU PA GoldSim model.
  • Appendix 17—Quality Assurance Project Plan
    Information on the systematic monitoring and evaluation of the various aspects of performance assessment model development to ensure a quality product, the standard operating procedure for the development of the GoldSim model, and a user guide.

A performance assessment (PA) is a quantitative, technical evaluation to determine whether a disposal facility can meet federal and state performance standards to protect public health and safety. It considers:

  • potential radiation exposures from the disposal site to the general public or inadvertent intruders by evaluating different scenarios for exposure;
  • potential radiological dose, using appropriate modeling and methodologies, to determine if there is reasonable assurance that the potential dose will be below the regulatory standard;
  • the stability of the site during operation, closure, and post-closure, including site conditions, potential pathways for transport of radiological materials, the potential for environmental releases, and disposal depth; and,
  • performance and institutional control periods sufficient to protect public health and safety.

EnergySolutions requested a license amendment to allow it to accept large quantities of depleted uranium for disposal at its facility. The Nuclear Regulatory Commission (NRC) recommended site-specific performance assessments for depleted uranium to assess whether disposal of this unique waste stream would meet public health and safety requirements. Based on direction from the Radiation Control Board, the Division of Radiation Control (DRC) initiated rulemaking to specifically address this issue. On April 10, 2010, the Radiation Control Board approved the Depleted Uranium Performance Assessment Technical Analysis rule. This rule requires a quantitative compliance period for DU of a minimum of 10,000 years, with additional qualitative simulations for the period of peak radiation dose occurring at approximately 2 1⁄2 million years.

On June 1, 2011, EnergySolutions submitted a 960-page, site-specific performance assessment that identified critical data, facility design, and modeling procedures for DU disposal at its facility. This performance assessment took into account public input from DRC stakeholder scoping meetings held in November 2010 and February 2011.

In August 2013, DRC hired an outside contractor from Virginia, S. Cohen & Associates (SC&A), to evaluate the PA for adequacy. DRC sent a Completeness Review (CR) to Energy Solutions in October 2013 and asked the facility to: 1) respond to agency comments and 2) supply any missing or additional information for the PA. DRC reviewed the PA for technical accuracy and regulatory compliance, submitted division issues or concerns to the facility in a series of three Interrogatories. EnergySolutions revised the initial design of the DU disposal cell and resubmitted the portion of the modeling report related to cell performance, as well as an updated compliance report, in June and July of 2014.

Depleted Uranium Performance Assessment Overview

2011 Performance Assessment References

Presentations 2010- 2011

Presentations are available from a June 1, 2011 Stakeholder Forum briefing.

November 2010 and February 2011

DRC sponsored Technical Education discussion sessions about the performance assessment on November 9-10, 2010, and on February 1, 2011. Information from these discussions was taken into consideration as the final performance assessment was developed. Presentations from all three sessions and Webcasts of the November sessions are posted.

Additional References

For further information, contact Charles Bishop ( 622-2211.

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