DRC-2022-020992 - 0901a068810e584f

DRC-2022-020992 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. [phone]
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

October 19, 2022

Kathy Weinel, Quality Assurance Manager
Energy Fuels Resources (USA) Inc.
225 Union Blvd., Suite 600
Lakewood, CO 80228

RE: Division Response to Request for Interpretation of Stack Sampling Frequency

Dear Ms. Weinel:

In a letter dated September 13, 2022, Energy Fuels Resources (USA) Inc. (EFRI) requested that the
Division of Waste Management and Radiation Control (Division) provide an interpretation of the
quarterly stack sampling frequency specified in Nuclear Regulatory Commission (NRC) Regulatory
Guide 4.14, Section 2.1.1 as it pertains to stack sampling at the White Mesa Mill (Mill). EFRI made this
request because the Mill’s Radioactive Materials License (RML) states in License Condition 11.2:

“The licensee shall implement an effluent and environmental monitoring program as described in
Sections 2 through 7 of the NRC Regulatory Guide 4.14 Radiological Effluent and
Environmental Monitoring at Uranium Mills...”

Section 2.1.1 of the NRC Regulatory Guide 4.14 states: “Effluents from the yellowcake dryer and
packaging stack should be sampled quarterly during normal operations.”

Discussion

NRC Regulatory Guide 4.14, Section 2.1.1 Stack Sampling states:

“Effluents from the yellowcake dryer and packaging stack should be sampled at least quarterly
during normal operations. The sampling should be isokinetic, representative, and adequate for
determination of the release rates and concentrations of uranium. The sampling should also be
adequate for the determination of release rates and concentrations of thorium-230, radium-226,
and lead-210 if this data cannot be obtained from other sources.”
(Over)
Page 2

In 2014, the NRC had Oak Ridge Associated Universities (ORAU) prepared a report called
TECHNICAL BASIS DOCUMENT TO SUPPORT THE REVISION OF REGULATORY GUIDE 4.14,
REVISION 1, “RADIOLOGICAL EFFLUENT AND ENVIRONMENTAL MONITORING AT URANIUM
MILLS.” Section 3.1.3.1, Stack Sampling, discusses among other things the purposes of stack sampling.
This document says:

“Some general purposes for stack sampling include:

• Demonstration of compliance with regulatory requirements and dose constraints
• Development of the release rate (e.g., Bq/s, Ci/min) from a stack in order to estimate the dose
to the public
• Identification of excessive concentrations being released that require corrective action
• Detection of long-term variations in releases which may indicate deteriorating Equipment”

EFRI continues in their letter dated September 13, 2022 to explain that NRC Regulatory Guide 4.14
assumes that “normal operations” means ore being processed and yellowcake is being produced. It also
assumes that the ore being processed, and yellowcake is being produced throughout the entire calendar
year. Therefore, sampling frequency on a quarterly basis can be interpreted once each calendar quarter.

However, it has been documented by both EFRI and the Division that the Mill does not produce
yellowcake throughout an entire calendar year. Instead, yellowcake is produced periodically as the
demand dictates. During the 2007 RML renewal process, the Division modeled, using MILDOS, the
emissions coming from the Mill. In Table 1 (see below) of the write up of that modeling
(DRC-2017-002763), it shows that between the years 2007 and 2014 the Mill did not operate for an
entire calendar year.

Table 1: Percentage of Time Mill Operated Annually*

2007 2008 2009 2010 2011 2012 2013 2014
Percent of
days the
Mill was
operational
in the year
42% 64% 38% 56% 68% 31% 36% 68%
*These values are estimates based on the number of days that the grizzly/feed conveyor/sag mill were operated. This does
not mean that the Mill's yellowcake dryers were running for the same length of time since the Mill will process materials
until a certain level is reached before the dryers are put into operation. Additionally, the dryers must be preheated before the
yellowcake can be dried.

Conclusion

The purpose of stack sampling is to obtain a representative sample of stack emissions while the yellow
cake dryers are being used. The data from stack sampling is used to calculate compliance with public
radiological dose requirements found in R313-15-301 (10 CFR 20.1301). It is also documented that the
Mill does not operate throughout an entire calendar year. So, the assumption that a Mill operates for an
entire calendar year and that stack sampling requires quarterly sampling, meaning in a calendar quarter,
does not fit with the actual operations at the White Mesa Mill.

Page 3

The Division Staff has concluded that the term “quarterly”, for the purpose of stack sampling at the Mill,
does not mean a calendar quarter but instead means any three (3) consecutive months, not to exceed
90 consecutive days, during which the yellowcake dryers are operating and producing air emissions
from the stacks. This interpretation will:
• Allow the Mill flexibility in scheduling stack sampling events;
• Still meet the intent of NRC Regulatory Guide 4.14 of performing stack sampling quarterly; and
• Still provide the Mill and the Division representative data to demonstrate compliance.

If you have any questions, please call Ryan Johnson at [phone].

Sincerely,

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

DJH/RJ/wa

c: Grant Sunada, Health Director, San Juan Public Health Department
Ronnie Nieves, Environmental Health Director, San Juan Public Health Department
Russell Seeley, District Engineer, UDEQ