DRC-2025-000935

299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111
[phone] ▪ Fax: [phone] ▪ www.energysolutions.com

February 5, 2025 CD-2025-022

Mr. Doug Hansen, Director
Division of Waste Management and Radiation Control
P.O. Box 144880
Salt Lake City, UT 84114-4880

Re: Groundwater Quality Discharge Permit Number UGW450005 (GWQDP) – Request
for Compliance Status Change Approval, Ra-226+Ra-228 in Monitoring Well
GW-77

Dear Mr. Hansen:

This letter requests a return to baseline monitoring status for compliance monitoring well
GW-77, presently in probable out-of-compliance (POOC) status for the sum of radiums
(Ra-226+Ra-228). EnergySolutions requests the Director of the Division of Waste
Management and Radiation Control (DWMRC) provide prompt approval for this well, which
has been sampled for radium-226 and radium-228 since December 2019 for 21 consecutive
quarters, to in-compliance status and a return to annual sampling.

On November 20, 2019 (CD19-0234), EnergySolutions notified the Director that the
compliance status change from annual baseline monitoring to POOC status due to
exceedance of the Ra-226+Ra-228 Groundwater Protection Level (GWPL) in the 2019
annual groundwater sample collected from well GW-77.

Table 1 provides well GW-77 Ra-226+Ra-228 concentration data for the 2019 annual sample
and subsequent quarterly POOC groundwater samples. The most-recent eleven consecutive
quarterly POOC sample results are less than respective GWPLs for this well (14 total
samples including duplicates). It has had no exceedances since February 2022.
EnergySolutions observed no evidence of contamination, i.e., detection of man-made
radioisotopes, changes in the uranium-234/uranium-238 ratio, or changes in general
chemistry, in the annual groundwater samples collected from 2019 to 2024 at well GW-77.

To evaluate the potential of a slow increase in radium concentrations at well GW-77 in the
absence of any other impacts to groundwater chemistry, EnergySolutions provides Figure 1,
which shows the sum of radiums concentration from the first sample collected from the well
on November 24, 1998 to the most recent sample collected on October 10, 2024. No trend in
the sum of radiums concentration is observed in the sum of radiums dataset. The slope of a
linear regression line is -5x10-5 pCi/L. Regression predicts the concentration of the first
sample collected on November 24, 1998 is 4.57 pCi/L and the concentration of the most
recent sample collected on October 10, 2024 is 4.55 pCi/L, a difference of 0.02 pCi/L. As
noted previously in CD-2024-036 (February 26, 2024) and CD-2024-179 (August 28, 2024),
the variability of concentrations recorded in the sum of radiums dataset for well GW-77 is
due to a combination of natural fluctuations and analytical uncertainty as opposed to slowly
increasing concentrations caused by Clive Facility operations. Based on data collected to
Mr. Doug Hansen
February 5, 2025
CD-2025-022
Page 2 of 3
date and without the need to collect additional data, the sum of radiums concentration in well
GW-77 is not increasing.
EnergySolutions has previously submitted well status change requests for GW-77 in CD-
2024-110 (May 17, 2024) and provided a further Response to Information Request in CD-
2024-219 (October 16, 2024).
Should you have any questions regarding this request, please contact me at [phone].
Sincerely,
Mathew R Schon
Manager, Groundwater and Environmental Program
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.

Mr. Doug Hansen
February 5, 2025
CD-2025-022
Page 3 of 3

Table 1 – Groundwater Ra-226+Ra-228 Concentrations in
Compliance Monitoring Well GW-77
Date
Collected
Ra-226
Concentration
(pCi/L)
Ra-228
Concentration
(pCi/L)
Ra-226+Ra-228
Concentration
(pCi/L)
5/28/2019 1.84 ± 0.486 4.31 ± 1.24 6.15
12/9/2019 1.59 ± 0.273 3.21 ± 0.546 4.80
2/25/2020 1.50 ± 0.235 3.10 ± 0.401 4.60
6/22/2020 1.82 ± 0.449 2.61 ± 0.502 4.43
8/27/2020 1.68 ± 0.248 2.77 ± 0.561 4.45
8/27/2020 Dup. 2.00 ± 0.283 2.05 ± 0.532 4.05
11/12/2020 1.57 J ± 0.356 2.12 ± 0.360 3.69
11/12/2020 Dup. 1.62 J ± 0.355 2.61 J ± 0.390 4.23
2/18/2021 1.80 ± 0.280 2.44 ± 0.486 4.24
2/18/2021 Dup. 1.56 ± 0.269 2.70 ± 0.564 4.26
6/1/2021 1.61 ± 0.268 2.37 ± 0.497 3.98
8/19/2021 1.32 J ± 0.244 1.92 ± 0.402 3.24
8/19/2021 Dup. 1.69 J ± 0.300 2.76 ± 0.485 4.45
11/18/2021 1.93 ± 0.278 3.52 J ± 0.493 5.45
11/18/2021 Dup. 1.83 ± 0.283 3.28 J ± 0.481 5.11
2/24/2022 2.15 ± 0.624 3.23 ± 0.750 5.38
2/24/2022 Dup. 2.30 ± 0.603 3.29 ± 0.711 5.59
6/6/2022 1.68 ± 0.340 < 1.33 ± 0.793 3.01
8/16/2022 1.72 ± 0.311 2.53 ± 0.781 4.25
8/16/2022 Dup. 1.49 ± 0.292 2.86 ± 0.883 4.35
12/15/2022 1.44 ± 0.218 2.67 ± 0.478 4.11
3/27/2023 1.79 ± 0.417 2.78 ± 0.466 4.57
6/27/2023 1.86 ± 0.491 2.98 ± 0.778 4.84
8/17/2023 1.31 ± 0.401 3.58 ± 0.996 4.89
11/28/2023 1.45 ± 0.202 3.41 ± 0.927 4.86
11/28/2023 Dup. 0.994 ± 0.174 2.34 ± 0.841 3.33
3/25/2024 1.51 ± 0.395 3.51 ± 0.964 5.02
5/16/2024 1.40 ± 0.248 3.72 ± 0.778 5.12
8/20/2024 1.09 ± 0.431 2.08 ± 1.07 3.17
10/10/2024 1.36 ± 0.297 3.03 ± 0.744 4.39
10/10/2024 Dup. 1.54 ± 0.297 3.41 ± 0.906 4.95
Bold results exceed GWPL 5.46 pCi/L
J – Validation qualifier, result is estimated
pCi/L – picoCuries per liter

y = -2E-06x + 4.5655
R² = 5E-05
2.0
3.0
4.0
5.0
6.0
7.0
8.0
11/24/1998 8/20/2001 5/16/2004 2/10/2007 11/6/2009 8/2/2012 4/29/2015 1/23/2018 10/19/2020 7/16/2023
pC
i
/
L
Date
Figure 1 -Sum of Radiums Well GW-77