DRC-2024-006935

October xx, 2024
EnergySolutions, LLC
Attn: Jonathan C. Anderson, Environmental Compliance Manager
299 South Main Street, Suite 1700
Salt Lake City, UT 84111
RE:East Side Rotary Facility (ESRF) Petroleum Hydrocarbon Investigation- Investigation Summary and Proposed Next Steps for Investigation: Request for Information (RFI)
Dear Mr.Anderson:
On March 14, 2024, EnergySolutions provided a summary of the ESRF hydrocarbon investigation to date and proposed next steps via DRC-2024-004896 (CD-2024-053). In this submittal, EnergySolutions
proposes to install a well monitoring network of five groundwater monitoring wells where significant petroleum hydrocarbon impacts were observed. Three wells will also be evaluated for
vertical extent of contamination.
There remain several questions about the summary of work completed as well as the proposed next steps. They are listed below.
If a risk assessment is the approach that EnergySolutions would like to pursue, then TPH-GRO and DRO would not provide sufficient data. That approach would require analysis of individual
contaminants including all VOCs, SVOCs and BTEXN. Additionally, Regional Screening Levels (RSLs) would be used as opposed to Initial Screening Levels (ISLs).
Please add narrative to the radiological section of this report which addresses the Restricted Area compared to the Uncontaminated Unrestricted Area. Please provide the communication
referenced in the statement, “Based on communication from EnergySolutions, the analytical results did not identify radiological content in the groundwater samples above levels of concern.”
The area designated as “Vitro Embankment” in Figures 4,5, and 6 are not owned by EnergySolutions but the U.S. Department of Energy (DOE). Well bores B9 and B15 provided non-zero values
for TPH-GRO that mayoccur underthe DOE property. Please provide justification that no contamination has left the EnergySolutions property boundary to the southwestunder DOE property.

Proposed Next Steps:
The three wells suggested by Geosyntec to determine vertical extent of the hydrocarbon plume (e.g. B27, B13, and B11) do not appear to necessarily be in the same source for the plume
based on the Isoconcentration maps provided. B27 is listed as a separate former petroleum Above-ground Storage Tank (AST) than B13 and B11. The summary provided no justification that
the activities conducted at B27 were equivalent to the time and scale as B11 and B13. Because of this, another point nearB11 and B13 should be selected from the higher concentration
area the ESRF, ideally the three points would be downgradient, not cross gradient.
Additionally, as B27 does appear to be impacted by hydrocarbons, please also conduct a vertical extent at B27.
Please include a potentiometric surface map of the area with the suggested additional monitoring well locations for review.
If the groundwater flow direction is Northeast, please justify how B31 bounds the extent of the contamination when B30 and B24 both, “… indicate that there is a potential for petroleum
impacts to extend off-site.” As outlined in a March 12, 2024, letter from Geosyntec to EnergySolutions as part of the DRC-2024-004896 submittal.
Please submit the updated Work Plan and address the questions within 30 days of receipt of this letter.
If you have any questions, please contact Brandon Davis at 385-622-1873.
Sincerely,
Larry Kellum, Section Manager, Low-Level Radioactive Waste
Division of Waste Management and Radiation Control
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c:Jeff Coombs, Health Officer, Tooele County Health Department
Bryan Slade, Environmental Health Director, Tooele County Health Department
EnergySolutions General Correspondence Email
LLRW General Correspondence Email