DRC-2023-001522 - 0901a0688118b276

DRC-2023-001522 195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
Telephone [phone] • Fax [phone] • T.D.D. 711
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF WASTE MANAGEMENT
AND RADIATION CONTROL

Douglas J. Hansen
Director

February 27, 2023

Vern C. Rogers, Director of Regulatory Affairs
EnergySolutions, LLC
299 South Main Street, Suite 1700
Salt Lake City, UT 84111

RE: Federal Cell Facility Application Requests for Information (RFI);
Addendum to RFI O-29.

Dear Mr. Rogers:

The Division of Waste Management and Radiation Control (Division) hereby provides an Addendum to RFI
O-29 provided to EnergySolutions in a letter dated January 25, 2023, regarding the Federal Cell Facility
Application dated August 4, 2022.

More specifically, this Addendum is intended to provide additional clarity with respect to a table referenced
in RFI O-29. As the Division is requesting that EnergySolutions consider the mentioned table to assess GDP
Clean DU Uranium distributions, this Addendum provides the context and rational associated with the
derivation of the table discussed in RFI O-29.

If you have any questions regarding this letter, please call Otis Willoughby at [phone].

Sincerely,

Douglas J. Hansen, Director
Division of Waste Management and Radiation Control

DJH/OHW/wa

Enclosure: Addendum to Request for Information O-29

c: Jeff Coombs, EHS, Health Officer, Tooele County Health Department
Bryan Slade, Environmental Health Director, Tooele County Health Department EnergySolutions
General Correspondence Email
LLRW General Correspondence Email

Addendum to Request for Information O-29

Since the SRS DU sampling results are not to be used to represent GDP Clean DU, a literature search was
performed to identify an alternative data source. Table 1 shows the U-234, U-235, and U-238 concentrations
in depleted uranium with several different U-235 weight percentages that were identified during search. In
Table 1 the U-234 and U-238 concentrations are linked to the U-235 composition, e.g., if 0.25% U-235 is
specified, then the U-234 and U-238 compositions are 0.0005% and 99.7495%, respectively.
Table 1: Depleted Uranium Composition and Concentration
Uranium
Isotope
10CFR 20, App B,
footnote 3a
Leggett &
Meck 2018
OEDC
2001
IAEA
2022a
10CFR 20, App B,
footnote 3a
wt% wt% wt% wt% wt% atom%
U-235 0.2 0.25 0.3 0.45 0.711 0.720
U-234 0.0003 0.0005 0.001 0.0025 0.0052 0.005
U-238b 99.7997 99.7495 99.699 99.5475 99.2838 99.275
Concentration (pCi/g)
U-235 4.33E+03 5.41E+03 6.49E+03 9.74E+03 1.54E+04
U-234 1.88E+04 3.14E+04 6.27E+04 1.54E+05 3.26E+05
U-238 3.37E+05 3.37E+05 3.37E+05 3.36E+05 3.35E+05
Total 3.6E+05 3.74E+05 4.06E+05 5.0E+05 6.77E+05
a 10CFR 20, App B, footnote 3 and IAEA 2022 U-234 and U-238 percentages were calculated
for this study from the provided U-235 assay and the total DU concentration. b This study calculated the U-238 composition by subtracting the U-235 and U-234 percentages
from 100. This may differ somewhat from the source document values, which may have been
rounded.

Uranium composition can be given in either weight percentage or atom percentage. The right two top
columns of Table 1 present the two approaches for natural uranium and show that because all three uranium
isotopes have nearly identical atomic masses, there is not much difference between the two approaches. In
Table 1 all the DU compositions are presented as weight percentages.
In Table 1 the U-235 concentration in the 0.2 wt% column is 3.56 times smaller than its concentration in the
0.711 wt% column, as expected since 0.711 wt% / 0.2 wt% = 3.56. However, the U-234 concentration in the
0.2 wt% column is 17.3 times smaller than its concentration in the 0.711 wt% column, while the U-238
concentration is virtually unchanged, i.e., 0.995.
Figure 1 show the breakdown of the inventory of DOE DU as a function of U-235 weight percent.

Figure 1: DOE Depleted Uranium Inventory as a Function of U-235 Weight Percent

NAC-0023_R5, Table 1 indicates the 686,500 Mg (in 57,122 cylinders) of DU is available for disposal at the
three GDPs. Table 1 also indicates that only 48,362 cylinders would be disposed of at Clive. Table 2
provides three estimates of Clive-disposed DU distribution by U-235 weight percent; the first follows the
Figure 1 distribution, the second assumes that all the Clive DU is at lower end of the Figure 1 distribution,
while the third assumes that all the Clive DU is at higher end of the Figure 1 distribution.
Table 2: GDP Clean DU Distribution and U-235 Weight Percent
U-235 wt%
Range
DOE
(Mg)
Disposed at Clive (Mg)
DOE Low High
< 0.21 225,666 191,059 225,666 120,387
0.21 to < 0.24 10,014 8,478 10,014 10,014
0.24 to < 0.26 192,002 162,557 192,002 192,002
0.26 to < 0.28 6,617 5,602 6,617 6,617
0.28 to < 0.31 65,406 55,376 65,406 65,406
0.31 to < 0.50 180,265 152,620 81,516 180,265
0.50 to < 0.60 961 814 0 961
0.60 to <
0.711 5,568 4,714 0 5,568
Total 686,500 581,221 581,221 581,221
Average U-235 Weight Percent
Range Low 0.19 0.19 0.16 0.22
Range Middle 0.25 0.25 0.22 0.28
Range High 0.32 0.32 0.28 0.33

As shown at the bottom of Table 2 the Average U-235 Weight Percent was a calculated value. For the DOE
case, the U-235 wt% Range mid-points were used, for the Low case the U-235 wt% Range low-points were
used, and for the High case the U-235 wt% Range high-points were used. As expected, the bottom of Table
2 shows that the smallest case is the Low-Low at 0.16 wt%, the DOE-Middle is in the middle at 0.25 wt%,
and the largest case is the High-High at 0.33 wt%. The corresponding U-234, and U-238 Weight
Percentages and Concentrations were calculated interpolating the Table 1 values, and are shown in Table 3.
Table 3: Recommended GDP Clean DU Uranium Distributions
Uranium
Isotope
Weight Percentage
Low-Low DOE-Middle High-High
U-235 0.16 0.25 0.33
U-234 0.00024 0.0005 0.00129 NAC-0023_R5, Mean
U-238 99.8398 99.7495 99.6687 Table 2 Corrected
Concentration (pCi/g)
U-235 3.46E+03 5.41E+03 7.14E+03 2.97E+03 3.57E+03
U-234 1.50E+04 3.14E+04 8.10E+04 3.31E+04 3.98E+04
U-238 3.373E+05 3.370E+05 3.367E+05 2.72E+05 3.27E+05
For ease of comparison, Table 3 also provides the mean uranium concentrations from NAC-0023_R5 both as
they appear in Table 2 and corrected from “(pCi/g of DUO3 waste)” to “(pCi/g of DU waste)”, as discussed
above.
The Table 3 concentrations could be used to form a distribution, e.g., uniform, triangular. However, if this is
done, then specifying the U-235 Weight Percent determines not only the U-235 concentration but also the
concentrations of U-234 and U-238.