DRC-2025-001040

March 27, 2025Matthew R. Schon, Manager, Groundwater and Environmental ProgramEnergySolutions, LLC
299 South Main Street, Suite 1700
Salt Lake City, UT 84111
RE:Groundwater Quality Discharge Permit UGW450005: Response to the Request for Information Related to a Request for Approval to Construct an Evaporation Pond
Second round of Requests for additional Information
DearMr. Schon:
The Division of Waste Management and Radiation Control (Division) has reviewed your letter dated January 16, 2025 (CD-2025-008/DRC-2025-000239) responding to the initial set of Requests
for Information (RFI) distributed by the Division via letter dated July 29, 2024 (DRC-2024-006175).Listed below, the Division responses to CD-2024-172/DRC-2024-006647 as well as follow-up
RFIs to be addressed to support these modifications. The numbering and organizationcorresponds to the initial RFI creation in letter DRC-2024-006544. RFI numbers greater than #8 under
“Engineering” are considered new topics for discussion:
Engineering:
The Division acknowledges the response to this RFI. After construction, it is suggested that EnergySolutions adequately maintain and observe these vents during the facilitation of the
Pond. The Division shall inspect this aspect of the pond per Best Available Technology (BAT) inspections post-construction under a separate letterhead.
The Division acknowledges the response to Engineering RFI #2 to #8, therefore these RFIsare considered resolved and closed.
Located in the “2024 Evaporation Pond CQA/QC Plan” under INTRODUCTION, third paragraph, item #6 notes, “Lift thickness measurement can be made by means of the grade pole method or by
the GPS survey method utilized during the 2024 Class A West Phase 6 Final Cover project”. The letter (DRC-2024-006508) sent to EnergySolutions regarding GPS requirement to be utilized
in the 2024 Class A West Phase 6 Final Cover Project restricted the use of those methods to that project. Should EnergySolutions choose to utilize similar methods prescribed during that
construction process, they shall be treated under this separate submittal and under no circumstances should the variance request be referenced in this discussion of the project (i.e.
referencing the variance letter should a dispute in misinterpretation arise during the course of the 2024 Evaporation Pond construction project). Please revise this page within the submission
to omit the consideration of the 2024 Class A West Phase 6 Final Cover Project.
Section 2.2.7 of the “2024 Evaporation Pond CQA/QC Plan” discusses the sequence of construction of the new groundwater wells. The subsection notes the wells, “will be considered for
installation during or following the construction of the Pond”. The Division has internally discussed this sequence and requests EnergySolutionsto construct the wells prior to construction
to allow for adequate baseline groundwater testing prior construction. Please revise the submission or respond to this RFI suggesting alternatives with justification.
The Division is concerned for the lack of frequency mentioned for the Non-Destructive Seam Testing within Specification 40. Please provide a minimum requirement for testing.
The following Engineering RFIs can be found within the original submission letter (CD-2024-080/DRC-2024-005275):
Engineering Drawing Sheet 23003 C04 displays cross-section C “SPILLWAY CROSS-SECTION”. The 60 mil HDPE primary liner appears to be installed at the crest of the embankment at the spillway
by means of “BATTEN & BOLT”. The Division is concerned that this could pose as a weak point in the liner system due to this portion of the liner not tied into the anchor trench. Please
provide clarification to the intention of this design or revise the drawing to address these concerns.
Engineering Drawing Sheet 23003 C05 displays Detail 6 “APRON DETAIL”. The leader indicated that CLEAN SAND FILL shall be placed and compacted under the interface of the liner and concrete
apron. The Division is concerned that this area may be subjected to erosion and degradation due to the high use in the area in which the sand can migrate between the geosynthetic layers.
Please provide justifications for the intention of this design that would alleviate the concern for sediment migration under this liner.
Engineering Drawing Sheet 23003 C06 displays cross-section H “SUMP CROSS SECTION”. It appears that the Drainage Net will be punctured to allow the HDPE Pipe to travel through the liner.
The Division is concerned that water can possibly traverse below the elevation of this puncture and entrap liquid under the Leak Detection System. Please provide justifications for the
intention of this design that would alleviate the concern for sediment migration under this liner
Engineering Drawing Sheet 23003 C06 displays Cross-Section H “SUMP CROSS SECTION”. The CONCRETE FOOTING appears to be resting on the liner.
This design assumes that the liner trench depth must be adjusted at this area based on the dimensions called out in Detail 9 on Engineering Drawing Sheet 24003 C07. Please clarify the
construction methodologies that will result in this product. Please include information regarding the concrete placement or pre-cast concrete installation, and earthwork modifications
if applicable.
The Division is concerned that the liner can be subjected to potential differential settlement or differential liner material deformation due to the change in geotechnical material utilized
within the anchor trench. Please provide justification to alleviate these concerns or revise the design.
Surety:
The Division acknowledges the response to both RFIs #1 and #2 within this section, therefore this RFI is resolved and closed.
Environmental:
The response to this RFI appears to sufficiently evaluate the impacts of the construction and operation of the 2024 Evaporation Pond to the current Environmental Monitoring Plan. The
Division generally agrees with the analysis provided in this response, however, this subject matter will continually be discussed separately. The current Environmental Monitoring Plan
does not consider analyses of the increasingly expanding facility as well as different and new sources of radiological transmission. The purpose of this RFI is due to the main concern
for the potential of these types of ponds to be completely dry (i.e. during extreme arid climatic conditions) allowing for a high concentration of evaporates to easily transport via
wind or other disturbance. It is imperative that EnergySolutions shall prevent this scenario by means of monitoring and maintaining, or provide an engineered solution. At this time,
this RFI is resolved and closed.
The Division acknowledges the responses to the RFI and sub-sections.
The Division agrees with the new location of Station F-35R and suggests that the data resulting from this exchange shall be assessed post-construction. This RFI sub-section is resolved
and closed.
The Division agrees with the construction methodologies for protecting Soil Station S-24, however, it is suggested that this Soil Station to be relocated and re-established in a similar
manner to Station F-35R. If EnergySolutions agrees with this approach, please revise the appropriate drawings to address this RFI.
The Division acknowledges the response to both RFIs #3 through #5 within this section, therefore this RFI is resolved and closed.
Please resubmit the appropriate portions of the revised original submission for the Division to complete an assessment. If you have any questions, please call Carlo Romanoat 385-977-7573.
Sincerely,
Larry Kellum, Section Manager
Division of Waste Management and Radiation Control
LK/CR/wa

Enclosure(s):
c:Jeff Coombs, EHS, Health Officer, Tooele County Health DepartmentBryan Slade, Environmental Health Director, Tooele County Health DepartmentEnergySolutions General Correspondence EmailLLRW
General Correspondence Email