DRC-2024-005680

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

May 17, 2024 CD-2024-110

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 radium
isotopes (Ra-226+Ra-228). EnergySolutions requests the Division of Waste Management
and Radiation Control (DWMRC) provides approval by June 30, 2024, to avoid unnecessary
additional sampling of well GW-77, which has been sampled quarterly for radium-226 and
radium-228 since December 2019.

This request is identical to the September 30, 2022, request to return wells GW-64 and
GW-89 to baseline monitoring status (CD-2022-169), which was approved by DWMRC on
January 5, 2023 (DRC-2022-024130).

On November 20, 2019 (CD19-0234), EnergySolutions notified DWMRC of 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.

As reported in submittal CD19-0234, the exceedance likely represents natural fluctuation of
groundwater Ra-226+Ra-228 concentrations. Clive Facility groundwater is naturally saline
and non-potable without treatment, with total dissolved solids greater than 10,000 milligrams
per liter. The universal GWPL for Ra-226+Ra-228, 5 picocuries per liter, is a drinking-water
based maximum contaminant level (MCL). Background concentrations of Ra-226+Ra-228
in Facility groundwater commonly exceed this MCL, as documented by the approval of
background-based GWPL exceptions for 20 compliance monitoring wells, including GW-77
(GWQDP Table 1B). This makes the sum of radium isotopes a poor indicator parameter for
contaminant monitoring without relief for background concentrations exceeding the MCL.

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 eight consecutive
quarterly POOC sample results are less than respective GWPLs for this well.
EnergySolutions observed no evidence of contamination, i.e., detection of man-made
radioisotopes or changes in general chemistry, in the annual groundwater samples collected
from 2019 to 2023 at well GW-77.

Mr. Doug Hansen
May 17, 2024
CD-2024-110
Page 2 of 3

EnergySolutions rescinds its October 7, 2022, request for modification of the GWPL for sum
of radium isotopes in well GW-77 (CD-2022-175). EnergySolutions will provide comment
to DWMRC’s response (DRC-2024-004500) to CD-2022-175 under a separate cover.

Should you have any questions regarding this request, please contact me at [phone].

Sincerely,

Jon Anderson
Environmental Compliance Manager

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.

Jonathan C.
Anderson
Digitally signed by
Jonathan C. Anderson
Date: 2024.05.17
13:16:24 -06'00'

Mr. Doug Hansen
May 17, 2024
CD-2024-110
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
Bold results exceed GWPL 5.46 pCi/L
J – Validation qualifier, result is estimated
pCi/L – picoCuries per liter