DRC-2025-001525

299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
May 7, 2025 CD-2025-093
Mr. Doug Hansen, Director Division of Waste Management and Radiation Control 195 North 1950 West Salt Lake City, UT 84114-4880
Subject: Radioactive Material License UT2300249 and Ground Water Quality Discharge Permit UGW450005: Response to a Request for Information from the Modification of the Open Cell Time Limit
Dear Mr. Hansen: EnergySolutions hereby responds to an April 21, 2025 request for information received from the Director of the Division of Waste Management and Radiation Control regarding the Open Cell Time Limitation promulgated in Part I.E.6 of Ground Water Quality
Discharge Permit (Permit).1 EnergySolutions appreciates the Director’s thorough evaluation and the opportunity to provide clarification concerning the relationship between Conditions 42 and 74 of Radioactive Material License UT 2300249 (License) and the open cell time limitation (Limit) under the Permit. EnergySolutions also herein responds to the Directors’ desire for clarification of the impact of deconstruction and
evaluation the facility’s Cover Test Cell and the Limit. Director’s Request: To move forward with a modification request, please provide the following for the open cell time limitation: • A timeline that includes when it was determined that the 18-year open cell time limit found in Part I.E.6 of the GWQDP could not be met, as well as events related to exceeding the Open Cell Time Limitation. • Correspondence about the Cover Test Cell and how it impacted on the delay of final cover construction for the CAW.
EnergySolutions herein provides a comprehensive timeline and regulatory history of the Limit for the Class A West (CAW) embankment at the EnergySolutions facility in Tooele County, Utah. In providing this history and timeline, EnergySolutions also supports a Limit of 25 years or longer for bulk Low-Level Radioactive Waste (LLRW) managed within the CAW embankment, detailing historical development, regulatory milestones,
Cover Test Cell and new final cover design-related delays, and conditions for compliance.

1 Hansen. D.J. “Modification of the Open Cell Time Limitation, Class A West (CAW) Embankment – Request for Information for Ground Water Quality Discharge Permit No. UGW450005 (GWQDP) and Radioactive Material License (RML) UT 2300249.” (DRC-2025-000105) Letter from the Division of Waste Management and Radiation Control to Vern Rogers of EnergySolutions, April 21, 2025.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
The Limit refers to the maximum duration open portions of an active disposal facility (a
distinct operational unit where waste is placed) may remain active before it must be covered or permanently closed (with final cover as part of closure). Utah’s regulations aim to minimize environmental risks such as vector attraction, odors, fires, and leachate generation by requiring timely covering and closure of waste embankments. Neither statues nor rules explicitly define or use the term "Open Cell Time Limit" but impose
standards for final cover, as well as closure timelines, which effectively limit the time waste can remain exposed or unclosed. The Open Cell Time Limit is indirectly governed by:
• UAC R313-25-9(1): General performance assessment requirements for LLRW
disposal.
• UAC R313-25-19: General requirement to satisfy performance objectives.
• UAC R313-25-23: Stability of the disposal site after closure.
• UAC R313-25-27(3): Stability of the disposal site after closure.
• UAC R317-6-1: Rule R317-6 establishes standards for protecting groundwater
quality, primarily through permitting and discharge controls for facilities that may impact groundwater, such as landfills. However, it does not directly address LLRW disposal embankment operations, waste placement, or closure timelines, including open cell time limits.
The Utah regulations effectively limit open cell time through final cover requirements,
ensuring that waste is not left exposed for extended periods. However, the rules do not explicitly cap the total operational life of an active disposal embankment (i.e., the time from initial waste placement to final closure), as this depends on the embankment’s capacity and waste receipt rate. R317-6’s lack of direct relevance to open cell time limits highlights that groundwater protection is addressed through other rules which focus on
monitoring rather than operational timelines. Timeline of the Open Cell Time Limit Development The Limit refers to the maximum duration open portions of an active disposal facility (a distinct operational unit where waste is placed) may remain active before it must be
covered and permanently (with final cover as part of closure).
• Prior to Establishment (Before 1994)
Prior to 1994, EnergySolutions’ Permit was silent on a limit on the duration a disposal embankment could remain open and active.2

2 Ostler, D.A. “Final Ground Water Quality Discharge Permit No. UGW450005.” Letter from the Division of Water Quality to Charles A. Judd of Envirocare, March 20, 1990.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com

• Initial Limit Establishment of 12 Years (1994 - 1999)
The Director introduced a 12 year "Open Cell Time Limit" requirement in Part 1.E.6 of the Ground Water Quality Discharge Permit UGW450005, issued on November 1, 1994,3 to enhance groundwater protection by minimizing the potential for contaminant leaching from EnergySolutions’ Low Activity
Radioactive Waste (LARW) disposal embankment (operated in accordance with Radioactive Material License UT2300249). The Director’s justification for adding an Open Cell Time Limit centered on reducing the exposure time of waste in open cells, thereby limiting the risk of precipitation-driven leachate generation that could infiltrate and contaminate groundwater.
This requirement has been retained in all subsequent permit modifications to maintain stringent oversight and adapt to evolving environmental regulations, reflecting the Director’s commitment to safeguarding Utah’s groundwater.
• Class A Embankment Licensing with 12-Year Limit (2000 - 2005)
Initial modeling of the Class A Embankment performance used the Hydrologic
Evaluation of Landfill Performance (HELP) model established a maximum open cell duration of 12 years.4 Developed by Adrian Brown Consultants5 and further validated by Whetstone and Associates,6,7,8,9,10 these models underpinned early license conditions in Radioactive Material License UT2300249 and GWQDP UGW450005, Part I.E.6.11 The 12-year limit relied on conservative infiltration
and evaporative zone depth (EZD) assumptions, provisionally set at 18 inches in the HELP model, as noted in the Director’s 2007 license renewal review.

3 Pehrson, F.C. “September 6, 1994 Preliminary Draft, Proposed Modified Ground Water Discharge
Permit No. UGW450005.” Letter from the Division of Water Quality to Dennis Romankowski of Envirocare, September 7, 1994.
4 U.S. Environmental Protection Agency, Schroeder, P.R.; Lloyd, C.M.; Zappi, P.A.; and Aziz N.M. The Hydrologic Evaluation of Landfill Performance (HELP) Model, User’s Guide for Version 3, EPA/600/R-94/168a, September 1994. 5 Adrian Brown Consultants, Inc. “LARW Open Cell Modeling Report,” prepared for Envirocare of Utah,
21 p. plus attachments, July 23, 1997. 6 Whetstone Associates. “Revised Envirocare of Utah Western LARW Cell Infiltration and Transport
Modeling”, Document 401 OT.000719, July 19, 2000. 7 Whetstone Associates. “Envirocare of Utah Class A Open Cell Modeling Report”, Document 4101T.020617, June 17, 2002. 8 Whetstone Associates. “Envirocare of Utah LLRW Open Cell Modeling Report”, Document
4101T.03050S, May 5, 2003. 9 Whetstone Associates. "LLRW Open Cell Modeling Results for Years 7-12," technical memorandum to
Dan Shrum (Envirocare of Utah, Inc.). Document 4101T.030828, August 28, 2003. 10 Whetstone Associates. “Response to Interrogatories, Open Cell Modeling, technical memorandum to Dan Shrum (Envirocare of Utah, Inc.)”. Document 4101T.050119, January 15, 2005. 11 Adrian Brown Consultants, 1997, cited in “Draft Cover Test Cell Project Review”, Page 41.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com

• Class A North Embankment Licensing with 18-Year Limit (2006-2007)
In conjunction with licensing the Class A North embankment,12,13,14 EnergySolutions sought approval to extend the Limit to 18 years.15 This extension reflected confidence in the HELP model’s conservative assumptions and the reliance upon extreme precipitation events.
In 2008, EnergySolutions submitted modeling conducted by Whetstone that demonstrated as compliant longer open cell durations, assessing open cell durations up to 25 years.16 Using site-specific data, the models confirmed minimal groundwater impacts, supporting an extension beyond 18 years.
• Cover Test Cell Influence on Limit (2008–2012)
Concerns over the representation of in-field conditions by the parameters used in the infiltration modeling led the Director to require EnergySolutions “… to complete construction and begin operation of an ‘Unsaturated Flow Test Pad’” (known now as the Cover Test Cell) prior to October l, 2001.17 Construction was completed and operation (in the form of data collection) began on September 19,
2001.
“The original purpose of the [Cover Test Cell] was to (i) demonstrate the ability of engineered low-level waste (LLW) embankment cover systems at the facility to minimize infiltration and (ii) evaluate cover-system soil properties, including volumetric water content and matric potential.”18
The Cover Test Cell consisted of a lysimeter overlain with the cover elements constructed to the required specifications. Moisture content, moisture potential, and temperature probe instruments were placed at specific locations within the Cover Test Cell during construction. Runoff and infiltration monitoring

12 Rogers, T.K. “Amendment and Modification Request – Class A North Disposal Embankment.” (CD04-
0481). Letter to Dane Finerfrock of the Utah Division of Radiation Control from Envirocare of Utah. October 27, 2004.
13 Shrum. D.B. “Revised Class A North Disposal Embankment License Amendment Request.” (CD04-0548). Letter to Dane Finerfrock of the Utah Division of Radiation Control from Envirocare of Utah.
December 23, 2004. 14 Rogers, T.K. “Class A North Disposal Embankment License Amendment Request – Revision 2” (CD05-
0024). Letter to Dane Finerfrock of the Utah Division of Radiation Control from Envirocare of Utah. January 17, 2005.
15 URS. “Review of Revised Class A North Embankment Amendment Request,” dated December 29, 2004. 16 Rogers. T.K. “Groundwater Quality Discharge Permit No. UGW450005: Request for Modificaiton –
Open Cell Time Limit” (CD08-0039). Letter to Dane Finerfrock of the Utah Division of Water Quality from EnergySolutions. February 12, 2008.
17 Section 1.2 of the Ground Water Quality Discharge Permit UGW450005. 18 Lundberg, R. “Review and Audit of EnergySolutions’ Cover Test Cell (CTC) Corrective Action Plan and Related Documents.” Letter to Sean McCandless of EnergySolutions from the Utah Division of Radiation Control. January 31, 2012.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
instruments were also included to measure critical flow rates. The entire Cover
Test Cell was surrounded by a three-foot runoff berm.
In 2009, the Cover Test Cell, intended to validate infiltration models, faced instrumentation failures, including water content reflectometers (WCRs) and heat dissipation units (HDUs), due to salinity, calibration issues, and datalogger malfunctions.19 WCRs were disconnected in 2009, rendering soil moisture and
matric potential data unreliable.20 Even so, EnergySolutions maintained a position that valued data is still being generated by the Cover Test Cell.21 Data generated:
1. Validated the model in terms of infiltration through the cover and discharge through the lysimeter;
2. Verified temperature extremes in the clay layers to determine freeze depths
in the clay, requiring instrumentation to measure temperature through the sacrificial soil and into the clay interfaces; and,
3. Water balance data mirrored projected modeling results (where the lysimeter water balance was calculated as input (precipitation) minus output (surface runoff, drainage, and evaporation) minus the change in soil
storage.
Infiltration and temperature data obtained from the Cover Test Cell over its life cycle illustrated that actual drainage measurements are well below the infiltration rates predicted by modeling efforts. Furthermore, the cover design is adequately protecting the radon barriers from freeze/thaw conditions.
On January 31, 2012, the Director issued a letter that disagreed with the value of data being generated by the Cover Test Cell and required a Corrective Action Plan be developed.22 The Director’s conclusion cited the following concerns:
• Unreliable Cover Test Cell data failed to validate infiltration rates or the
18-inch EZD; and,
• Lysimeter drainage likely reflected construction water, not precipitation
infiltration.

19 Orton, T. “Cover Test Cell – Notification of Instrument Error.” (CD17-047). Letter from EnergySolutions to Scott Anderson of the Division of Waste Management and Radiation Control. March 2, 2017. 20 Draft Cover Test Cell Project Review, Pages 34, 41
21 Shrum. D.B. “Radioactive Material License No. UT2300249, License Condition 28: Unsaturated Flow Post-Model Audit Assessment.” (CD08-0208) Letter to Dane Finerfrock of Utah Division of Radiation
Control from EnergySolutions. July 7, 2008. 22 Lundberg, R. “Review and Audit of EnergySolutions’ Cover Test Cell (CTC) Corrective Action Plan and Related Documents.” Letter to Sean McCandless of EnergySolutions from the Utah Division of Radiation Control. January 31, 2012.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
The Director then offered two options to correct the Cover Test Cell’s
deficiencies:
“Option 1: One, approach to implementing a [Cover Test Cell]
[Corrective Action Plan] would involve construction, instrumentation, and monitoring of a new of rebuilt [Cover Test Cell] or another comparable monitoring system and technology, based on knowledge and experience
gained from failures of the past. The new [Cover Test Cell] or monitoring
technology would need to use monitoring procedures compatible with and
durable in harsh desert environments,”23 or,
“Option 2: As an alternative to rebuilding the [Cover Test Cell], or to building a new [Cover Test Cell], the [Director]would be willing to
consider design modifications leading to a more-conservative and more-
protective [final] cover system.”24
Following review of these options, EnergySolutions “… committed to provide a revised cover design to the [Director] by December 24, 2012.”25 The Director formalized this commitment as Condition 42 in Amendment 14 to Radioactive
Material License UT2300249.
“On or before December 21, 2012, the Licensee shall submit a revised
cover design (including at least descriptions, design calculations, drawings, and specifications) and an assessment addressing performance of the revised Class A West cover design and transport of potential releases from the proposed Class A West disposal unit.”26
In compliance to License Condition 42 and the Director’s suggested [Cover Test Cell] corrective options, EnergySolutions submitted descriptions, design calculations, drawings, specifications, and an assessment addressing performance of an alternate Class A West cover design on April 11, 2012.27

23 Ibid. 24 Ibid.
25 URS Corporation. “Utah Division of Radiation Control: EnergySolutions LLRW Disposal Facility – Class A West Amendment Request; Safety Evaluation Report.” Technical Report prepared by URS Corporation for the Utah Division of Radiation Control, June 2012, pg. 112. 26 Lundberg, R. “Class A West Amendment Request: Radioactive Material License UT2300249
Amendment 14, GWQDP UGW450005 Modification; Final Agency Action.” Letter to Sean McCandless of EnergySolutions from the Division of Radiation Control, November 26, 2012.
McCandless, S. “ Radioactive Material License #UT 2300249 and Ground Water Quality Discharge Permit No. UGW450005. Amendment and Modification Request – Class A West Embankment: Complete, Electronic ” (CD12-0095) Letter to Rusty Lundberg of the Division of Radiation Control, April 11, 2012.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com

Following review of the design and performance evaluation, the Director requested additional information in a letter dated June 7, 2013.28 Meetings to further evaluate the alternate cover design were held between the Director and EnergySolutions on July 16, 2013 and August 29, 2013. EnergySolutions responded to the Director’s request with additional information on December 30,
2013.29
Following an additional review, in a letter dated July 2, 2014, the Director requested a second round of information.30 The request cited as requirements several NRC recommendations from NUREG-1573. Following meetings between the Division and EnergySolutions on July 17, 2014 and November 13, 2014,
EnergySolutions responded to the Director’s request with additional information in a letter dated January 26, 2015.31 EnergySolutions provided an additional briefing to the Director on January 28, 2015. EnergySolutions then submitted supplemental site-specific data to the Director in a letter dated February 6, 2015.32
Following a meeting with the Director on September 15, 2015 to discuss possible
resolutions of the Director’s outstanding concerns, EnergySolutions received a third round of requests from the Director in a letter January 7, 2016.33 EnergySolutions proposed a draft resolution and fourth revised cover design in a letter dated February 3, 2016.34

28 Hultquist, J.H. “Round 1 Request for Information regarding Updated Site-Specific Performance Assessment, dated October 8, 2012. Radioactive Material License UT2300249.” Letter to Sean McCandless of EnergySolutions from the Division of Radiation Control, June 7, 2013. 29 Rogers, V.C. “Utah Radioactive Material License (RML UT2300249) Updated Site-Specific
Performance Assessment; Response to Round 1 Request for Information. (CD13-0359). Letter to Rusty Lundberg with the Utah Division of Radiation Control from EnergySolutions. December 30, 2013.
30 Hultquist, J.H. “UPDATED SITE-SPECIFIC PERFORMANCE ASSESSMENT – ROUND TWO INTERROGATORIES; Request for Additional Information. Radioactive Material License UT2300249” Letter to Sean McCandless of EnergySolutions from the Division of Radiation Control, July 2, 2014. 31 Rogers, V.C. “Revised Renewal Application for Utah Radioactive Material License UT2300249;
Responses to Round 1 Interrogatories and updated site-specific Performance Assessment.” (CD15-0021). Letter to Rusty Lundberg with the Utah Division of Radiation Control from EnergySolutions. January 28,
2015. 32 Rogers, V.C. “Utah Radioactive Material License (RML UT2300249) Updated Site-Specific Performance Assessment Supplemental Response to Round 2 Interrogatories” (CD15-0030). Letter to Rusty Lundberg with the Utah Division of Radiation Control from EnergySolutions. January 30, 2015.
33 Anderson, S.T. “Outstanding Issues for Performance Assessment for Blended-Waste Disposal and for the Proposed Evaporative Cover System.” (DRC-2015-009469) Letter to Vern Rogers of EnergySolutions
from the Division of Waste Management and Radiation Control, January 7, 2016. 34 Rogers, V.C. “Radioactive Material License UT 2300249; Response to the Division’s Verbal Request for Information of February 3, 2016” (CD16-0027). Letter to Scott Anderson with the Utah Division of Radiation Control from EnergySolutions. February 5, 2016.
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299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
A meeting between the Director and EnergySolutions was held on October 17,
2016 to discuss the resolution of the Director’s outstanding concerns. EnergySolutions informally offered a fifth revised cover design and test proposal that involved destructive testing of the Cover Test Cell to support the fifth revised cover design to the Director via electronic mail message on November 2, 2016. A meeting to discuss pathways to resolution was conducted with the Director and
EnergySolutions on March 15, 2017, including a sixth revised cover design and cover test offered by EnergySolutions.
EnergySolutions then suggested with a seventh revised cover design with a draft Stipulated Consent Agreement (Agreement) on April 13, 2017.35 The draft Agreement proposed deconstructive testing of the Cover Test Cell as a means of
validating the in-field performance of clay layers within the seventh revised cover design. Even though EnergySolutions’ suggestion for deconstructive testing of the Cover Test Cell as an added means to validate the in-service performance of the seventh revised cover design clay materials was directly tied to the Director’s approval of the seventh revised cover design, the Director inserted a requirement
for this deconstructive testing as License Condition 28 via amendment 23 to Radioactive Material License (without accepting the seventh revised cover design).36 EnergySolutions also submitted a request to RESERVE Condition 42 of the License (having satisfied it by submission of the first alternate final cover design in 2012).37 The Cover Test Cell was destructively tested in a final report of
the observations and testing results submitted to the Director in 2020.38
• Determination of Potential Non-Compliance with 18-Year Limit (2013–2015)
As EnergySolutions delayed final cover construction in order to explored the viability of alternate final cover designs, in accordance with Option 2 suggested in the Director’s 2012 letter,39 concerns were raised by EnergySolutions’ over the
impact of development of the alternate cover design on compliance with the Limit.

35 Rogers, V.C. “Radioactive Material Licenses UT2300249: Condition42 – Updated Cover Design” (CD17-0094). Letter to Scott Anderson with the Utah Division of Radiation Control from
EnergySolutions. April 13, 2017. 36 Anderson, S.T. “Approval of License Amendment 23: Radioactive Material License UT 2300249.”
(DRC-2018-004844) Letter to Vern Rogers of EnergySolutions from the Division of Waste Management and Radiation Control, August 1, 2018.
37 Rogers, V.C. “Radioactive Material Licenses UT2300249: Condition42 Amendment Request” (CD18-0020). Letter to Scott Anderson with the Utah Division of Radiation Control from EnergySolutions.
January 24, 2018. 38 Orton, T. “Cover Test Cell Deconstruction Study Final Report” (CD-2020-0123). Letter to Ty Howard
with the Utah Division of Radiation Control from EnergySolutions. August 7, 2020. 39 Lundberg, R. “Review and Audit of EnergySolutions’ Cover Test Cell (CTC) Corrective Action Plan and Related Documents.” Letter to Sean McCandless of EnergySolutions from the Utah Division of Radiation Control. January 31, 2012
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• Conditional Approval of 25-Year Time Limit (2016)
To accommodate time for alternate cover design, EnergySolutions requested an extension of the 18-year Limit to 25-years for select lift areas in the Class A West embankment.40 As justification supporting the extension, EnergySolutions noted the following conservatisms included in the original modeling used to justify the
18-year Limit to the Director:
• “DRC chose to limit the open cell time limit to 18 years on the basis of the extreme climate simulation. As provided in the Statement of Basis for the July 29, 2010 Permit modification: "Results of the detailed DRC staff review are provided in a June 3, 2010 technical memorandum, and indicate that: 1. One
sensitivity case in the EnergySolutions' modeling report (high precipitation) is
the most appropriate basis for an administrative decision on duration of open cell conditions. 2. Said high precipitation case predicts that open cell conditions cause the waste to be wetter than the initial waste moisture content assumed in the previous closed cell infiltration models. These closed cell
models were central to previous approved performance assessment models for
the LLRW embankments. 3. The time at which the open cell model predicted excessive waste moisture content occurred sometime between years 17 and 18 years in the simulation.”41
• “The 18-year time limit, approved on July 29, 2010, is based on Whetstone
Associates, ‘EnergySolutions LLRW Open Cell Modeling Results’, September
2009. This report justifies an open cell time limit of up to 25 years for the base case expected average precipitation (7.97 in/yr) and an 8-year fill rate. Section 5 summarizes that this scenario would lead to moisture increase equal to ‘ ... 91 % of the total moisture storage or 81.1 % of the moisture deficit
required to reach quasi-steady state conditions at the start of the closed cell
modeling.’ In other words, under the base case modeled scenario, the closed cell model input assumptions are maintained and the cell can be left open for up to 25 years without bringing the closed cell modeling into question.”42

40 McCandless, S. “Ground Water Quality Discharge Permit No. UGW450005: BAT Performance and Best Management Practice Standards - Extension Request, Part l.E.6, Open Cell Time Limitation” (CD13-
0277). Letter to Rusty Lundberg with the Utah Division of Radiation Control from EnergySolutions. October 8, 2013.
41 ibid. 42 ibid.
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In 2014, the Director conditionally approved EnergySolutions’ request to extent
the Limit to 25-years for a select area of 644, 022 square feet on the north end of the Class A embankment.43
In 2015, EnergySolutions requested that a 25-year Limit extension be expanded to the entire Class A West footprint, due to continued delays in approval of an alternate cover design and the need for additional data collection indicated that the
18-year Open Cell Time Limit might not be met.
“EnergySolutions understands the Division is compiling a list of uncertainties regarding the Class A West revised evapotranspirative cover design proposed in October 2012 (CD12-0258). In order to support adequate time for the Division’s consideration of the revised design,
EnergySolutions herein requests an expansion of the Open Cell Time
Limitation 25-year extension previously granted by the Division of Radiation Control on June 5, 2014 to include the remaining portions of the Class A West embankment ….”44 [emphasis added]
In 2016, the Director granted EnergySolutions’ 2015 request to extend the 25-year
Limit to the entire Class A West footprint (under the same conditions as were promulgated in the Director’s original 2014 select extension).45
“The Division of Waste Management and Radiation Control (Division) has completed your request (CD15-0236) for an extension to the open cell time limitation for the Class A West embankment to 25 years (which is
currently set at 18 years after the date of initial placement of any LLRW
waste in any portion of the open cell) as described in Part I.E.6 of Ground Water Quality Discharge Permit, No. UGW450005.
As you know, the Division is still evaluating the proposed ET cover system. The Division understands that some areas of the embankment are
approaching the open cell time limitation, and cover construction needs to
start. Other areas may need to start cover before a final decision on the proposed cover is made. The Division also agrees with EnergySolutions' assessment that extending the open cell time limitation would not pose additional risk to human health or the environment.”46 [emphasis added]

43 Lundberg, R. “Response to EnergySolutions' October 8, 2013 Request for Extension on Open Cell Time
Limitation: Conditional Approval.” Letter to Sean McCandless of EnergySolutions from the Utah Division of Radiation Control. June 5, 2014.
44 Rogers, V.C. “Ground Water Quality Discharge Permit No. UGW450005: BAT Performance and Best Management Practice Standards – Temporary Expansion Request, Part I.E.6 - of June 5, 2014 Open Cell
Time Limitation Approval” (CD15-0236). Letter to Scott Anderson with the Utah Division of Waste Management and Radiation Control from EnergySolutions. October 16, 2015.
45 Anderson, S.T. “Extension of Open Cell Time Limitation Ground Water Quality Discharge Permit UGW 450005 Conditional Approval.” (DRC-2016-001929) Letter to Vern Rogers of EnergySolutions from the Division of Waste Management and Radiation Control, January 29, 2016. 46 Ibid.
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It is important to note that EnergySolutions’ 2015 extension request applied “to
include the remaining portions of the Class A West embankment.” Similarly, the Director’s broad approval applied to “… an extension to the open cell time limitation for the Class A West embankment to 25 years (which is currently set at 18 years after the date of initial placement of any LLRW waste in any portion of the open cell…).” Even so, at some time following the Director’s 2016 approval,
and unsolicited by EnergySolutions, the Director modified Part 1.E.6 of the Permit with language distinctly different from the 2015 Request and 2016 Approval.
“Any modification of this 18 -year limitation shall require prior Director approval with area-specific plans, schedule, and the submittal of
justification. Said justification must be submitted to the Director at least
180 days prior to the expiration date of the respective 18-year open cell time limit. Failure to secure Director approval prior to expiration of the 18 -year deadline shall not be cause for the Permittee to postpone construction of the cover of the Class A West cell in accordance with the
currently approved engineering design and specifications in Part I.D. 4 of
this Permit.
The Permittee was given an extension (to 25 years) to the Open Cell Time Limitation for parts of, or all of lift areas POI, N0I, N04, N06, NI 1, N12, N14, Nl5, NI 7, N20, N23, and MIO as defined in the Permittee's
Extension request, Part I.E.6, Open Cell Time Limitation letter dated
October 8, 2013. The extension is conditioned on annual precipitation of 9.32 inches or above for two consecutive years causing a reevaluation of the extension.” [emphasis added]
It is EnergySolutions’ hope that the inaccurate adoption of the language in the
Director’s 2016 approval into Part 1.E.6 of the Permit is inadvertent. EnergySolutions suggests Part 1.E.6 of the Permit be administratively corrected to accurately reflect the Director’s 2016 Approval.
• Final Cover Strategy and Construction Milestones (2017–2020)
Because the Permit limit of Section I.H.17 still applied while the alternate final
cover design was under joint review, EnergySolutions decided in 2017 that it would be optimally prudent to discontinue further efforts to comply with Option 2 of the Director’s January 31, 2012 Letter,47 and proceed with efforts to minimize contact of waste with precipitation by constructing final cover according to the original rock armor design approved with Amendment 14 of Radioactive Material
License UT2300249. Since then, EnergySolutions has aggressively constructed very large sections of final cover over the Class A West Embankment as a show

47 Lundberg, R. “Review and Audit of EnergySolutions’ Cover Test Cell (CTC) Corrective Action Plan and Related Documents.” Letter to Sean McCandless of EnergySolutions from the Utah Division of Radiation Control. January 31, 2012.
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of good faith towards protecting groundwater from precipitation falling upon
active sections of the Class A West embankment (see Table 1).48,49
• Final Cover Construction Progress Reports (2021–Present)
As construction of significant phases of final cover construction proceeded, EnergySolutions met and briefed the Director’s staff (LLRW Section Manager) on August 3, 2021, November 8, 2022, March 30, 2023, and June 13, 2023 to discuss
closure progress. As EnergySolutions in good faith had actively proposed and the Director extensively evaluated several alternate cover designs, EnergySolutions and the Director agreed that continued construction of large portions of the final Class A West cover (in areas where waste had been placed up to the design top of waste level) was an appropriate resolution of future compliance with Open Cell
Time Limitation. To support aggressive waste placement, the LLRW Section Manager instructed EnergySolutions that future licensing efforts to expand Class A disposal capacity must exclude bulk waste (to minimize time necessary to bring remaining open portions of the Class A West embankment to the design top of waste level necessary for continued final cover construction). EnergySolutions
also verbally agreed to formally report closure progress with annual As-Built Reports (provided in accordance with Condition V.F.13 of state-issued Part B Permit EPA ID No. UTD982598898 and Condition I.H.6 of Ground Water Quality Discharge Permit UGW450005. Closure progress has been included with the 2023 and 2024 annual As Built Reports.50,51

48 Rogers, V.C. “State-issued Part B Permit EPA ID No. UTD982598898 - Condition V.F.13 and Ground
Water Quality Discharge Permit UGW450005 - Condition I.H.6: 2024 Annual As-Built Report for the Radioactive Material Licenses UT2300249 and UT2300478” (CD-2024-241). Letter to Doug Hansen with the Utah Division of Waste Management and Radiation Control from EnergySolutions. November 25, 2024.
49 Rogers, V.C. “Radioactive Material License UT 2300249: Class A West Embankment Phase VI Final Cover Construction Report with As-Built Drawings” (CD-2024-251). Letter to Doug Hansen with the
Utah Division of Waste Management and Radiation Control from EnergySolutions. December 19, 2024. 50 Rogers, V.C. “Radioactive Material License UT2300249: Enhancement of the Condition 74 Decontamination and Decommissioning Plan Submitted under Permanent Claim of Business Confidentiality” (CD-2024-066). Letter to Doug Hansen with the Utah Division of Waste Management
and Radiation Control from EnergySolutions. April 2, 2024. 51 Rogers, V.C. “Radioactive Material License UT2300249; Groundwater Quality Discharge Permit
UGW450005: 2024 Annual Update to the Condition 74 Decontamination and Decommissioning Plan Submitted under Permanent Claim of Business Confidentiality” (CD-2024-237). Letter to Doug Hansen with the Utah Division of Waste Management and Radiation Control from EnergySolutions. November 25, 2024.
Mr. Doug Hansen CD-2025-093 May 7, 2025 Page 13 of 16
299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
Table 1 – Class A West Embankment Open Cell and Final Cover Construction Tracking

YEAR
LONGEST OPEN CELL OF
UNCOVERED WASTE (CELL ID)
LONGEST TIME OPEN OF
UNCOVERED WASTE (years)
CUMULATIVE FOOTPRINT SIZE OF
COVERED WASTE (ft2)
2000 H12 0 2001 H12 1 2002 H12 2 2003 H12 3
2004 H12 4
2005 H12 5 2006 H12 6 2007 H12 7 2008 H12 8
2009 H12 9
2010 H12 10 2011 H12 11 2012 H12 12 2013 H12 13
2014 H12 14
2015 H12 15 2016 H12 16 2017 H12 17 2018 H12 18
2019 H12 19 354,054
2020 H12 20 726,179 2021 H17, H18, H20 21 1,140,011 2022 H17, H18, H20 22 1,535,229 2023 E22 23 1,862,349
2024 E22 24 2,180,243
Mr. Doug Hansen CD-2025-093 May 7, 2025 Page 14 of 16
299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
In 2021 and 2023, the Director selected a new LLRW Section manager and hired
several new inspectors. EnergySolutions thought it prudent to confirm that the inaccurate adoption of the language in the Director’s 2016 approval into Part 1.E.6 of the Permit was inadvertent and asked for the Director’s formal affirmation.54
On February 8, 2024, the Director responded to EnergySolutions 2023 request for
affirmation,55 with the following conclusions:
1) “The letter references a 2016 Division extension approval (DRC-2016-001929) of the Open Cell Time Limitation while an alternate cover design study was being evaluated. This extension was conditionally approved based on the expectation that, upon decision of the proposed final cover,
EnergySolutions would begin final cover construction in accordance with
approved engineering plans and specification on all lifts exceeding the 18-year limitation. Since the evaluation of an alternative cover design was abandoned in 2017, the conditional extension approval is no longer applicable.”56
EnergySolutions disagrees with the Director’s basis for this conclusion. The extension was not requested so that an alternate design could be approved, but rather “…[i]n order to support adequate time for the Division’s consideration of the revised design.”57 While EnergySolutions acknowledges that it ultimately decided it prudent to protect the site’s groundwater from uncovered
waste regions in the Class A West embankment by discontinuing further evaluation of alternate cover designs in order to proceed with cover construction, several years were still consumed in evaluation of multiple alternate designs. The 2015 extension specifically sought time for the Director to review these designs, and made no supposition if any would eventually be
approved.
2) “EnergySolutions [was] concerned that there is insufficient time available to respond with additional information following completion of the Division’s current review in order to begin the necessary contractor selection process by November 1, 2015 (a milestone necessary in order that proposals can be

54 Rogers, V.C. “Ground Water Quality Discharge Permit UGW450005 - Part I.E.6: Request for
Confirmation of 25-years as the Open Cell Time Limitation for the Class A West Embankment” (CD-2023-126). Letter to Doug Hansen with the Utah Division of Waste Management and Radiation Control
from EnergySolutions. June 28, 2023. 55 Hansen. D.J. “Response to EnergySolutions’ June 28, 2023, Request for Confirmation of 25-year Open Cell Time Limitation for the Class A West Embankment Groundwater Quality Discharge Permit Number (GWQDP) UGW450005.” (DRC-2024-002125) Letter from the Division of Waste Management and
Radiation Control to Vern Rogers of EnergySolutions, February 8, 2024. 56 Ibid.
57 Rogers, V.C. “Ground Water Quality Discharge Permit No. UGW450005: BAT Performance and Best Management Practice Standards – Temporary Expansion Request, Part I.E.6 - of June 5, 2014 Open Cell Time Limitation Approval” (CD15-0236). Letter to Scott Anderson with the Utah Division of Waste Management and Radiation Control from EnergySolutions. October 16, 2015.
Mr. Doug Hansen CD-2025-093 May 7, 2025 Page 15 of 16
299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
received and reviewed, a contractor selected, a construction contract
negotiated, and contractor labor and equipment mobilized in order to
commence construction activities by spring 2016)”58
EnergySolutions recognizes that the justification cited was included in its 2015 Request.59 However, the impact of the extension within the context continued evaluation of alternate cover designs after 2015 (in 2016 and 2017)
was regularly discussed with Division staff, as part of the joint evaluation efforts. If EnergySolutions and the Director were jointly evaluating alternate cover designs after the contractor selection time frame cited in the 2015 Request, it is unreasonable to assume that the Director continued 2016 and 2017 review efforts without further discussions with EnergySolutions “… in
order to begin the necessary contractor selection process by November 1,
2015.”60
As the Director recognized on several occasions since 2000, the model developed by EnergySolutions to assess the groundwater impacts from uncovered low-level radioactive
waste continues to be inherently conservative. This, compared to the actual site conditions since 2000, supports a 25-year Open Cell Time Limit for the Class A West embankment. Being still within the conditions analyzed by the approved open cell model, this acknowledgement will not lead to any additional impact to groundwater, human health, or the environment.

58 Hansen. D.J. “Response to EnergySolutions’ June 28, 2023, Request for Confirmation of 25-year Open
Cell Time Limitation for the Class A West Embankment Groundwater Quality Discharge Permit Number (GWQDP) UGW450005.” (DRC-2024-002125) Letter from the Division of Waste Management and
Radiation Control to Vern Rogers of EnergySolutions, February 8, 2024. 59 Rogers, V.C. “Ground Water Quality Discharge Permit No. UGW450005: BAT Performance and Best Management Practice Standards – Temporary Expansion Request, Part I.E.6 - of June 5, 2014 Open Cell Time Limitation Approval” (CD15-0236). Letter to Scott Anderson with the Utah Division of Waste
Management and Radiation Control from EnergySolutions. October 16, 2015 60 Hansen. D.J. “Response to EnergySolutions’ June 28, 2023, Request for Confirmation of 25-year Open
Cell Time Limitation for the Class A West Embankment Groundwater Quality Discharge Permit Number (GWQDP) UGW450005.” (DRC-2024-002125) Letter from the Division of Waste Management and Radiation Control to Vern Rogers of EnergySolutions, February 8, 2024.
Mr. Doug Hansen CD-2025-093 May 7, 2025 Page 16 of 16
299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111 [phone] ▪ Fax: [phone] ▪ www.energysolutions.com
Furthermore, EnergySolutions agreement with the LLRW Section Manager to 1) now
divert bulk waste disposal until open Class A West capacity is brought to top of waste; and 2) report to the LLRW Section Manager with annual Class A West closure progress should continue to be honored. Please contact me at [phone] if you have further questions regarding this
Response. Sincerely,
Vern C. Rogers Director of Regulatory Affairs

I 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.
Vern C.
Rogers
Digitally signed by Vern C. Rogers DN: cn=Vern C. Rogers, o=EnergySolutions, ou=Waste Management Division, email=[e-mail], c=US Date: 2025.05.08 06:08:50 -06'00'