DRC-2011-007451_7 - 0901a0688027e865

ATTACHMENT D
RADIATION PROTECTION MANUAL FOR RECLAMATION

Denison Mines (USA) Corporation

White Mesa Mill – Standard Operating Procedures

Book #20

Radiation Protection Manual for Reclamation

September 2011

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Book 20: Radiation Protection for Reclamation Activities, Section 1 Page 1 of 17

1.0 RADIATION MONITORING – PERSONNEL

This section contains the following procedures for personnel radiation monitoring
including: (1) airborne particulates (2) alpha surveys (3) beta/gamma surveys and (4)
urinalysis surveys.

1.1 AIRBORNE PARTICULATES

Sampling for personnel exposure to airborne particulate radionuclides, other than for
radon progeny, will be done utilizing two distinct sampling protocols: (1) personnel
breathing zone samplers, and (2) ambient air high volume samplers. Specific standard
operating procedures for these two collection methods are described in Section 1.1.2 and
1.1.3 below.

1.1.1 Frequency

For work where there is the potential to cause airborne radiation doses to site personnel,
the frequency and type of air sampling to be conducted is determined from measured air
concentrations:

0.01 DAC – 0.1 DAC Quarterly or monthly area air sampling and/or bioassay
measurements

> 0.1 DAC Continuous sampling is appropriate if concentrations are
likely to exceed 0.10 DAC averaged over 40 hours or
longer.

The RSO will determine the exact frequency of area air sampling, breathing zone
sampling and/or bioassay measurements and determine how many workers in a group of
workers performing similar jobs are to be equipped with breathing zone air samplers.
Higher airborne concentrations warrant more frequent use of area air samplers, bioassay
measurements, and breathing zone air samplers. Area air samplers may be used where
documentation exists showing the sample is equivalent to a breathing zone sample.
Breathing zone samples taken within one foot of the worker’s head are considered
representative without further documentation. Breathing zone air samplers are preferred
under work conditions of higher airborne concentrations. Table 1.1.1-1 below, from
Regulatory Guide 8.25, provides additional guidance for the RSO in designing and
implementing air sampling programs for specific jobs.

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Table 1.1.1-1
Air Sampling Recommendations Based on Estimated Intakes and Airborne Concentrations

Worker’s Estimated
Annual Intake as a
Fraction of ALI
Estimated Airborne
Concentrations as a
Fraction of DAC

Air Sampling Recommendations

< 0.1

< 0.01

> 0.01

Air sampling is generally not necessary.
However, monthly or quarterly grab samples or
some other measurement may be appropriate to
confirm that airborne levels are indeed low.

Some air sampling is appropriate. Intermittent or
grab samples are appropriate near the lower end of
the range. Continuous sampling is appropriate if
concentrations are likely to exceed 0.1 DAC
averaged over 40 hours or longer.

> 0.1

< 0.3

> 0.3

Monitoring of intake by air sampling or bioassay
is required by 10 CFR 20.1502(b).

A demonstration that the air samples are
representative of the breathing zone is appropriate
if (1) intakes of record will be based on air
sampling and (2) concentrations are likely to
exceed 0.3 DAC averaged over 40 hours (i.e.,
intake more than 12 DAC-hours in a week).

Any annual intake

> 1

> 5

Air samples should be analyzed before work
resumes the next day when potential intakes may
exceed 40 DAC-hours in 1 week. When work is
done in shifts, results should be available before
the next shift ends. (Credit may be taken for
protection factors if a respiratory protection
program is in place.)

Continuous air monitoring should be provided if
there is a potential for intakes to exceed 40 DAC-
hours in 1 day. (Credit may be taken for
protection factors if a respiratory protection
program is in place.)

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1.1.2 Breathing Zone Sampling

1.1.2.1 General

Breathing zone samplers (SKC pumps and accessory kits, or equivalent) are used to
determine airborne exposure to uranium while individuals are performing specific jobs.
The units consist of a portable low volume pump that attaches to the individuals belt,
tygon tubing and filter holder that is attached to the individual’s lapel or shirt collar. The
unit monitors airborne uranium in a person’s breathing zone. Pumps must be recharged
after 6 to 8 hours of use.

1.1.2.2 Applicability

Breathing zone samples are required:

 for all calciner maintenance activities,
 at least quarterly during routine operating and maintenance tasks on
representative individuals performing these tasks,
 when radiation work permits are issued in which airborne concentrations may
exceed 25% of 10 CFR Part 20 limits,
 weekly for yellowcake operations, or
 at the discretion of the RSO.

1.1.2.3 Procedure

The procedure for collecting a breathing zone sample is as follows:

1. Secure the breathing zone sampler, which has been charged and loaded with a filter
paper from the radiation department.

2. Secure the pump to the worker’s belt and the filter holder to the shirt collar or lapel.
Try to secure pump tubing to minimize restriction of motion.

3. Turn pump on (record the time pump was turned on) and continue monitoring until
the work being monitored is completed and the worker no longer is in the exposure
area. Record the time at which the job is complete.

4. Return the pump and accessories to the RSO, who will remove the filter paper for
analysis. Be sure to indicate accurately the total time taken by the work being
monitored.

5. Analysis of filter samples will be performed using a sensitive alpha detector. The
procedure is as follows: (a) count a background sample for ten minutes; (b) divide the
background count by ten to obtain the background count rate in cpm; (c) Place the
breathing zone sample in the instrument and count the sample again for ten minutes;
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(d) divide the sample count by ten to obtain the count rate in cpm; (e) subtract the
background count rate from the sample count rate; and, (f) record all data on the
Breathing Zone sampling analysis form (a copy of which is attached).

6. Record the total hours of exposure that are being assigned to the employee on the
Employee Exposure form, which is maintained in personnel folders. Be sure to
consider protection factors permitted by respirator use if the employee was also
wearing respiratory protection during the job.

7. The number of DAC hours assigned is calculated using the following formula:

DAC hours = Measured air concentration x Total hours of exposure
of exposure (DAC)(PF)

where: DAC = Derived Air Concentration (for uranium; 10 CFR Part 20,
Appendix B)

PF = protection factor for respirator use. If no respiratory
protection was used PF =1.

The measured air concentration must be in µCi/cc.

1.1.2.4 Calibration

Prior to use, calibration of the breathing zone samplers will be done using a calibration
method as described in Section 3.2.

1.1.2.5 Equipment – Breathing Zone Sampler

The equipment used for breathing zone samples consists of:

1. Personal sampling pumps
2. Gelman 37 mm Delrin filter holders, or equivalent
3. Gelman 37 mm type A/E glass fiber filters, or equivalent
4. Kurz Model 543 air mass flow meter, or equivalent

1.1.2.6 Data Record

Data maintained on file includes:

1. Time on and off for each sample pump.
2. Sampling location(s).
3. Individual’s name, identification number, etc.
4. Date and sample number.
5. Sample count rate.
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1.1.2.7 Calculations

The airborne concentration in µCi/cc is equal to the sample count rate minus the
background count rate in cpm divided by the instrument alpha efficiency, the sample
flow rate in cc/minute, the sample time in minutes and a conversion factor converting
dpm to µCi.

The calculation is:

Equation Number 1:

Airborne concentration = _____________(Count Rate)___________
(Time)(eff)(Conversion factor)(Flow Rate)

i.e. uCi = (cpm-Bkg) 1 uCi (1) (1)_
cc (eff)(2.22x106dpm)(cc/min)(min)

where: eff = cpm/dpm for counting instruments
cpm = counts/min
dpm = disintegrations/min
Conversion factor 1 µCi = 2.22x106 dpm
Flow Rate = cc/min
Collection time = min

Once the airborne concentration has been calculated it is possible to calculate personnel
exposure in microcuries (µCi). Personnel exposure is determined for an individual who
is working in an area at a known air concentration (µCi /cc) for a given amount of time
(hours) breathing the area air at an assumed rate. The breathing rate for a standard
person (Handbook of Radiological Health) is 1.20 cubic meters per hour (m3/hr).

The calculation for personnel exposure is:

Equation Number 2:

Exposure µCi = (µCi /cc)(1.20m3/hr)(hours of exposure)(conversion rate)

Where: µCi /cc = air concentration from Equation 1

1.20 m3/hr = breathing rate for standard man (ICRP)
hours of exposure = hours
conversion factor = 106cc/m3

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It is also possible to determine the percent or fraction of the Derived Air Concentration
(DAC) for a particular radionuclide using the information obtained from the exposure
calculation and dividing this value by the regulatory limit DAC listed in 10 CFR Part 20.

% DAC = Exposure in µCi / µCi limit 10 CFR Part 20

For the natural uranium (U-Nat) the DAC limits from 10 CFR Part 20 for insoluble Class
Y compounds are as follows:

 Weekly 1.0 x 10-3 µCi /week
 Quarterly 1.25 x 10-2 µCi /Qt
 Yearly 5.0 x 10-2 µCi /yr

1.1.2.8 ALARA/Quality Control

The RSO reviews each monitored result and initiates action if levels exceed 25% of 10
CFR 20 limits. At a minimum, ten percent (10%) of the air samples collected in a given
quarter will be recounted using the same instrument or using a different instrument and
these results will be compared to the original sample results. Deviations exceeding 30%
of the original sample results will be reviewed by the RSO and the samples will be
recounted again until the sample results are determined to be consistent. Additional QA
samples consisting of spiked air samples, duplicate samples and blank samples will be
submitted to the radiation department for counting. This will be based on ten percent
(10%) of the number of samples collected during a quarter. The sample results will be
compared to the spiked values, duplicate values, or blank (background) values of the
prepared sample. Deviations exceeding 30% of the determined spiked, duplicate or blank
value will be recounted. If no resolution of the deviation exceeding 30% is made the QA
samples preparation will be repeated. Periodic reviews by the RSO and the ALARA
audit committee will be made and documented to ensure quality maintenance and
ALARA control.

1.1.3 Airborne High Volume Sampling

Grab air sampling involves passing a representative sample of air through a filter paper
disc via an air pump for the purpose of determining the concentration of uranium in
breathing air at that location. Although the process is only measuring airborne
concentrations at a specific place and at a specific time, the results can often be used to
represent average concentration in a general area. A high volume sample pump will be
used for this purpose. Samples will be analyzed as per standard gross alpha analysis
procedures using a sensitive alpha detector.

1.1.3.1 Frequency and Locations

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The following principles used for the collection of area grab samples must be considered
when collecting a sample in order to obtain a representative air concentration that
workers may be exposed to during their assigned work tasks.

1. The locations selected for sampling should be representative of exposures to
employees working in the area.

2. For special air sampling, the sampling period should represent the conditions during
the entire period of exposure. This may involve sampling during the entire exposure
period.

3. For routine sampling, the sampling period must be sufficient to ensure a minimum
flow rate of 40 liters per minute (lpm) for at least 60 minutes.

4. Sample filters will be analyzed for gross alpha using a sensitive alpha detector.

5. Grab sampling procedures may be supplemented by use of Breathing Zone Samples
for special jobs or non-routine situations.

1.1.3.2 Sampling Equipment

Monitoring equipment will be capable of obtaining an air sample flow rate of at least 40
liters per minute for one hour or longer. Equipment utilized will be and Eberline RAS-1,
or a Scientific Industries Model H25004, or equivalent. Filter media will be of
appropriate micron pore diameter. Equipment is calibrated prior to each usage as per
Section 3.3 of this manual.

1.1.3.3 Sampling Procedure

Steps for collection of area airborne grab samples are as follows:

1. A high volume pump will be used for sample collection.

2. Check sample pump calibration.

3. Locate sampler at designated site. Insert a clean filter, using tweezers, into the filter
holder on the sampler. Do not contaminate the filter. Log start time and Mill
operating conditions at the site.

4. Collect a sample for a minimum of 60 minutes at a flow rate of 40 lpm.

5. After sampling is completed, carefully remove the filter, using tweezers, from the
filter holder and place it in a clean glassine envelope, or in the plastic casing
furnished with the filter.

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6. Log all sample data on the log sheet.
A. Sample location and number (also on the envelope).
B. Time on, time off and date.
C. Mill operating conditions at the site.
D. Sampler’s initials.

7. Analyze for gross alpha

1.1.3.4 Calculations

Perform calculations as described in Section 1.1.2.7.

1.1.3.5 Records

Logs of all samples taken are filed in the RSO’s files. Data are used to calculate
radiation exposures as described in Section 4.0.

Whenever grab sampling results indicate that concentrations in work locations exceed
25% of the applicable value in 10 CFR Part 20, Appendix B, time weighted exposures of
employees who have worked at these locations shall be computed. Calculations will
reveal an individual’s exposure in DAC hours. This value shall be assigned to the worker
and logged onto the worker’s “Employee Exposure to Airborne Radionuclides” form.
This form is in Section 4. Whenever special air sampling programs (as required for
cleanup, maintenance, decontamination incidents, etc.) reveal that an employee has been
exposed to airborne radioactive material, the calculated value shall also be entered on the
individual’s exposure form.

1.1.3.6 Quality Assurance

Calibration checks on each air sampler, prior to field use, ensure accurate airflow
volumes. Use of tweezers and new filter storage containers minimizes contamination
potential. Field logging of data during sampling and logging of identifying data on
sampled filter containers minimizes sample transposition. Quality control samples will be
analyzed as described in Section 1.1.2.8

Review of data by the RSO and by the ALARA Audit committee further assures quality
maintenance.

1.2 ALPHA SURVEYS

1.2.1 Restricted Area

The Restricted Area is defined as:

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1. The property area within the chain link fence surrounding the mill property and the
area enclosed to the north and east of the facility by the posted Restricted Area fence.

2. The active tailings and liquid waste disposal areas.

All personnel who enter the Restricted Area will monitor themselves each time they
leave the Restricted Area and at the end of their shift. The Radiation Safety Department
will review the monitoring information. All personnel exiting the Restricted Area must
initial a record of their monitoring activity.

1.2.2 Instrumentation

The instrumentation utilized for personnel alpha scanning is listed in Appendix 1 at the
end of this manual. Personnel alpha survey instruments are located at the exits from the
Restricted Area.

1.2.3 Monitoring Procedures

The monitoring procedure includes the following steps:

1. The alarm rate meter is adjusted within the range of 500 to 750 dpm/100 cm2 to
ensure a margin of 250 dpm/100 cm2 due to the low efficiency of this
instrumentation.

2. An individual monitors himself by slowly passing the detector over their hands,
clothing and shoes, including the shoe bottoms, at a distance from the surface of
approximately ¼ inch. An area that is suspected of possessing any contamination
(i.e. hands, boots, visible spotting/stain on clothing etc.) should be carefully
monitored by placing the detector directly on the surface and note the measurement.

3. Should an alarm be set off indicating the presence of contamination, the individual
should:
a. Resurvey themselves to verify the contamination.
b. If contamination is present the individual must wash the affected area and
again resurvey themselves to ensure the contamination has been removed.

4. If the decontamination efforts by the individual are not successful, then the Radiation
Safety personnel will be contacted to assess the situation. Further decontamination
may be required.

5. If an individual’s clothing cannot be successfully decontaminated, they must obtain
clothing from the warehouse to use and must launder the personal clothing in the
laundry room.

6. Individual surveys are to be logged and initialed.
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7. Access to and from the Mill’s Restricted Area by all Mill workers, contractors and
delivery personnel, other than Radiation, Safety and Environmental Staff, Senior
Laboratory personnel, Mill Management and Mill Supervisory personnel and others
as may be designated by the RSO, will be limited to one or more access points as may
be designated by the RSO from time to time.

8. A Radiation Technician will be positioned at each access point designated by the
RSO under paragraph 7 above during peak transition times, such as during breaks and
at the ends of shifts, to observe that each worker, contractor or delivery person is
performing a proper scan. This paragraph 8 will cease to apply to any such access
point if and when one or more automated full body scanners portals or the equivalent
are situated at the access point, which would require workers exiting at that location
to scan themselves by exiting through the portal, and the procedures in this Manual
are amended to incorporate the use and maintenance of such portal or portals.

1.2.4 Training

All employees will be trained on the proper scanning procedures and techniques.

1.2.5 Records

Log sheets will be collected daily and filed by the Radiation staff. Records will be
retained at the Mill. Contamination incidents will result in a written record, which is
maintained on file.

1.2.6 Limits/ALARA

Contamination limits for personnel scans are set at 1,000 dpm/100 cm2. Records will be
reviewed by the RSO to maintain levels noted as low as reasonable achievable.

1.2.7 Quality Assurance

A random check of an individual’s scanning technique provides quality assurance of the
monitoring procedures. Daily function checks using calibrated sources assures
instrumentation performance. Periodic review by the RSO and the ALARA audit
committee document and ensure quality control and ALARA maintenance.

1.3 BETA-GAMMA SURVEYS

Site employees working within the Restricted Area will be required to wear a personal
monitoring device (such as a TLD, LUXEL badge or other NVLAP approved device
which has been approved by the RSO and the SERP) during their work period. The
personal monitoring devices are normally issued to each employee quarterly; however,
during pregnancy or if the radiological potential for exposure to an individual is
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anticipated to be elevated and requires quick assessment the badges may be issued
monthly.

1.3.1 Monitoring Procedures

The monitoring procedures consist of:

1. Personnel issued personal monitoring devices will wear the device on the trunk
(torso) of the body. The personal monitoring device records beta/gamma radiation as
well as other forms of penetrating radiation such as x-rays. A personal monitoring
device is an exposure record of an individual’s personal exposure to radiation while
on the job. Therefore, personal monitoring devices are to remain at the Mill and
stored on the assigned dosimeter storage boards. All exposure records obtained by a
personal monitoring device which are not consistent with the exposure rates of work
tasks or work location measurements made throughout the Mill will be evaluated by
the RSO. This evaluation will result in an investigation by the RSO and a written
explanation of the findings. These written records will be maintained at the Mill.

2. Personal monitoring devices will be issued at a minimum quarterly and will be
exchanged by the Radiation Safety Department. Missing or lost badges will be
reported to management.

3. Female employees that become pregnant and continue to work during the course of
their pregnancy will be placed on a monthly personal monitoring device exchange
during this period. NRC Regulation Guide 8.13 provides guidelines to be followed
during pregnancy and is made part of this procedure.

1.3.2 Records

The Radiation Safety Department will maintain all occupational exposure records in the
departmental files:

1. Occupational exposure records are a part of an individual’s health record and, as
such, will be considered private information.

2. An individual may examine his/her exposure record upon request.

3. An employee terminating his/her employment with Denison Mines (USA) Corp. may
request a copy of his/her occupational exposure records.

4. The Radiation Safety Department on the signature of the employee will request prior
occupational exposure records.

5. Occupational exposure records will be made available to authorized company or
regulatory personnel.
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1.3.3 Quality Assurance

Periodic reviews by the RSO and the ALARA audit committee document and ensure
quality control and maintenance of conditions ALARA.

1.4 URINALYSIS SURVEYS

1.4.1 Frequency

Urinalyses will be performed on those employees that are a) exposed to airborne
yellowcake or involved in maintenance tasks during which yellowcake dust may be
produced, or b) routinely exposed to airborne uranium ore dust. Baseline urinalyses will
be performed prior to initial work assignments.

Urine samples are collected on a routine basis from mill employees as required in
Regulatory Guide 8.22. Samples will be collected from all other employees monthly. Bi-
weekly samples will be collected if individual exposures are expected to exceed 25% of
the DAC value. Non-routine urinalyses will usually be performed on employees who
have been working on assignments that require a Radiation Work Permit, and always on
any individual that may have been exposed to airborne uranium or ore dust
concentrations that exceed the 25% of the DAC level.

1.4.2 Specimen Collection

Clean, disposable sample cups with lids will be provided to each employee that will be
required to submit a urine specimen. The containers will be picked up at the
administration building before the individual enters the Restricted Area.

The container, filled with specimen, will be returned to the bioassay laboratory prior to
reporting to work. The name of the employee and the date of collection will be indicated
on the specimen cup.

A valid sample must be collected at least 40 hours, but not more than 96 hours, after the
most recent occupancy of the employee’s work area (after two days, but not more than
four days off).

The specimen should be collected prior to reporting to the individual’s work location. To
prevent contamination, the hands should be carefully washed prior to voiding.

Under unusual circumstances where specimens cannot be collected in this manner, the
worker will shower immediately prior to voiding.

1.4.3 Sample Preparation

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Equipment required:

 15 ml disposable centrifuge tubes with lids
 10 ml pipette
 1 mL pipette
 200 µL pipette
 5 µl pipette
 10 µl pipette
 Disposable tips for the above pipettes
 1,000 ppm uranium solution
 Spiking solution – 0.03 or 0.02 g/l of uranium in de-ionized water

After the specimens are received, they will be stored in a refrigerator until they are
prepared for analysis.

Sample preparation will be done in an area decontaminated to less than 25 dpm alpha
(removable) per 100 cm2 prior to preparation of samples. All of the equipment that is
used in sample preparation will be clean and maintained in such condition.

A log will be prepared and the following information will be kept for each urinalysis
performed:

Sample identification number
Name of employee submitting the specimen
Date of sample collection
Date the sample was sent to the laboratory
Date the results were received
Results of the urinalysis in µg/1
Indication of any spike used in µg/1

The centrifuge tubes will be marked with a sample identification number. 10 milliliters
of urine will then be pipetted into the centrifuge tube using the pipette device. Or 1
milliliters of urine will then be pipette into the centrifuge tube using the pipette device
(To prevent contamination, a new tip must be used for each specimen.) After each step
of the procedure, the proper entry must be made in the logbook.

The samples that are to be spiked for quality assurance purposes will then be prepared.
The spikes will be introduced into the sample with 5 µl or 10 µl pipettes. A new tip must
be used with each spike. With the standard spike solution (0.03 g/l of U), a 5 µl spike
will result in a 15 µg/l concentration for the 10 ml sample; the 10 µl spike will give 30
µg/l). The proper entry must be made in the logbook for each sample spiked.

After preparation has been completed, the QA samples are securely packaged as soon as
practicable and sent to the contract laboratory for analysis.
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The samples that are to be analyzed in-house will be placed in the chemistry laboratory’s
refrigerator until the analysis can be completed. A copy of the in-house analytical
procedure is described in Section 1.4.7.6.

1.4.4 Quality Assurance

To assure reliability and reproducibility of results, at least 25% of the samples that are
submitted for analysis will be used for quality assurance purposes. These samples will
consist of spikes, duplicates, and blanks (samples collected from individuals known to
have no lung or systemic uranium burden).

Spiked samples will be prepared as stated under sample preparation of this procedure.

Duplicates will be identical samples of the same specimen and/or spikes of identical
concentrations.

To assure reliability of the in-house analytical procedure, 10% of the samples will be sent
to a contractor laboratory for analysis. These samples will contain quality assurance
items designed to provide intra-laboratory comparisons.

1.4.5 Analysis

After the samples are collected as outlined in Guide 8.22, they are identified to the lab by
collection date and number. Urinalysis results must be completed and reported to the
Radiation Safety Department within seven days of the sample collection.

1.4.5.1 Equipment List

1. Specimen collection cups with disposable lids (VWR No. 15708-711 or equivalent)
2. Screw cap, disposable, graduated 15 ml centrifuge tubes (Corning No. 25310 or
equivalent)
3. Micro-pipettes 1 each 5, 5 each 10 µL (Oxford Model 7000 or equivalent)
4. Adjustable Finnpipette each 1,000 µL, 200 µL and 5 mL
5. Disposable micro-pipette tips for micro-pipettes (Oxford No. 910A or equivalent)
6. Fume Hood
7. Ultrasonic Cleaner
8. PE-SCIEX ELAN DRC II AXIAL FIELD TECHNOLOGY ICP-MS (or equivalent)
9. Polyscience Water Circulator (or equivalent)
10. Perkin-Elmer AS-10 Auto Sampler (or equivalent)
11. Thermo Scientific Vortex mixtures (or equivalent)

1.4.5.2 Reagent List

1. 1% to 2% Nitric Acid
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2. Concentrated Nitric Acid
3. 1,000 µg/ml Uranium Stock Solution, certified vendor prepared
4. Dilutions of the above stock solution, replaced bi-annually. Used for QA/QC.
5. Appropriate Cleaning Solution for Ultrasonic Cleaner
6. 1,000 µg/ml Uranium Stock Solution, purchased from certified vendor to use as
calibration standard at different dilutions

Ensure that all reagents used are within their expiration dates listed on each reagent
package, if applicable.

1.4.5.3 Premise

A portion of urine is diluted with 2% Nitric acid solution, mixed thoroughly and
analyzed.

1.4.5.4 Safety Precautions

1 Follow laboratory guidelines when working with acids.

2. Utilize all appropriate PPE.

1.4.5.5 Sample Preparation Procedure

1. Compare sample numbering with bioassay result sheet to insure order and eliminate
discrepancies.

2. To 15 ml centrifuge tube add 1 mL urine sample, 200 µL internal standard of 1,000
ppb and 2% Nitric acid to make up volume to 10 mL.

3. Maintaining sample order of left to right, front to back, lowest sample number to
highest sample number in the set.

4. Use vortex to mix it thoroughly.

5. Analyze using procedure on the ICP-MS described in section 1.4.5.6.

1.4.5.6 ICP-MS Procedures

Special considerations: Because of the high salt content of the samples, it is necessary to
clean the skimmer and sampler cones after each use.

1. Turn the argon on at the tank and set the delivery pressure at 80 pounds per square
inch (psi).

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2. Turn on the exhaust fan and the water supply to the ICP-MS. The water supply has to
have a delivery pressure of 70 psi. It may be necessary to change the filters on the
water supply in order to achieve sufficient water supply pressure. The ICP-MS will
not operate below this pressure.

3. Turn on the computer, monitor and printer.

4. On the windows desktop, double-click the ELAN icon.

5. Check the condition of the sample introduction system.

6. Check that the sample tubing and drain tubing leading from the peristaltic pump to
the spray chamber are properly set up and in good working condition. It is
recommended to use new tubes every day.

7. Place the capillary tubing into a container of 2% Nitric acid solution.

8. Open the instrument window, and then click the Front Panel Tab.

9. On the front panel tab click vacuum start.

10. When the instrument is ready, click Plasma Start.

11. After the plasma ignites, allow the instrument to warm up for 45 minutes.

12. To begin sample analysis, click the sample tab, build the sample analysis list and
click on analyze sample.

13. After the last sample, aspirate the blank long enough to clean the lines.

14. Allow the pump to run long enough without aqueous uptake to void all lines.

15. Turn the flame off and relax lines off of pump.

16. After 5 to 10 minutes, turn off the water supply, exhaust fan and argon.

All bioassay samples need to be analyzed three (3) working days from receipt in the
laboratory. Samples are extremely susceptible to contamination. Precautions should be
taken to minimize traffic and fugitive dust while samples are digesting.

1.4.6 Reporting and Corrective Actions

White Mesa Mill –Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 1 Page 17 of 17

As soon as the analytical results are received, they are entered in the logbook and the
entries are checked for correctness and completeness.

The lab report is returned to the Radiation Safety Department with results reported as
micrograms/liter of uranium. The information must be placed in the individual
employee’s exposure file and maintained as directed by the DRC.

The Radiation Safety Department is notified immediately of any sample with a
concentration greater than 35 micrograms/liter of uranium. Corrective actions will be
taken when the urinary uranium concentration falls within the limits listed in Table 1
(attached).

The Radiation Safety Department should compute the error on the control spiked samples
and advise the lab if the results are more than ± 30% of the known values. If any of the
results obtained for the quality assurance control samples are in error by a ± 30%, the
analysis must be repeated.

1.5 IN-VIVO MONITORING

In-vivo body counting for lung burdens of U-natural and U-235 will not be routinely
conducted. Monitoring will be conducted at the discretion of the RSO, samples may be
sent for a follow-up analysis for specific radionuclides in consultation with DUSA
management should potential exposure to an individual warrant.

Table 1
cORRECTIVE ACTIONS BASED ON MONTHl V URINARY URANIUM RESULTSa
Urinary Uranit~m
Concentration
Less than 15 ].J.g/L
15 to 35 J.iS/L
Greater than 35 J..lgfl
Confirmed to be greater
rhan 35 wgJL for two
.::onsecutiv~; specim~:ns,
confirmed to bti:
gteatcr than 130 1-lg/L
for any single specimen,
OT all' sampling indica-
rion of more than a
quarrerly limir of
in rake
Interpretation
Uranium ~:onfinement and air
sampling prosrams are
indicated to be adequate. b
Uranium confinement 11nd air
sampling may not provide an
adequate m~g.in of safety. b
Uranium confinement and
perhaps air sampling programs
are not acceptable. c
Worker may have exceeded
regulatory limit on intake.
Actions
None. Continue: ro review further bioassay results.
1. ConfJtm results (repeat urinalysis).
2. Identify the cause of eleYated urinary uranium and initi-
ate additional control measures if the result is con finned.
3. Examine air samplins data to determine the source and
concentration of intake. If air sampling results are
anomalous, investigate samplin~ procedures. Make correc·
tions if necessary.
4. Determille whether other workers could have been exposed
and perform bioassay measurements for them.
5. Consider work assignment limitations until the worker's
urinary uranium concentration falls below 1.5 wg/L.
6. improve uranium confinement controls or respiratory
protection program as investigation indicates.
1. Take the actions given above.
2. Continue operations only if it is virtually certain than no
other worker will excct:d a urinary uranium concentra-
tion of 35 vgfL.
3. Establish work restrictions for affected employees or
increase uranium confim~ment controls if ore dust or
high-temperature-dried yellowcake are invol"ed.
4. Analyze bioass11y samples weekly.
1. Take the actions gjven above.
2. Have urine specimr:J\ tested for albuminuria .
3. Obtain an i11 vivo count if worker n1ay have been exposed
to Class Y material or ore dust.
4. Evaluate exposures.
5. Establish further uranium confinement !::ontrols or
respiratory pro·rection requirements as indicated.
6. Consider continued work resrrictions on affected
employees until urinary concentrations are below 15 ]J.g/L
<tnd laboratory tests for albuminuria are negative.
11Use Flgurc:s 1.3 to adjust acrion levels for other frequencies of bio~y sampling. 1"hc model ~J:~ed in NUREG-0~74 (R~:f. 1) employs
fractional compositiOrt valu~:s (F • F2, F3) for Class D, Ctll!l8 W, and ClaM Y compon~::nts of yeUowcai<IO compQ\Wds. The assigJted valu~:~~
in NUREG.OIS74 11re b.as~:d on da\n frllm aVIlilable literature. The u:re of alternative Values ofF , F2, and F specific for a pa.-ticular opera.
tion ;~re :~ccc:ptablc provided (l) detail:; regarding-their detenninatiol\-are dcscti!>cd and merttiolhcd 'rt empldyce exposure rr;!cords (see para-
gtaph :!0.40l(c}(1) of 10 CFR P.,.-l 20) <~nd (2) thl:' model as published in NUREG-0574 is tllen used m the detcrmi.ution of alternative
urinalysi.~ frcque.tcies nn<l action levels.
bHowever, if a pciSol\ is cxp0$1!d to uranium ore dll!it or orhcr material of ClaiiS W or Y alone, refer ~o Section 6 of NUREG-0874
about tne po5Sibllity of' the need for conducting in vivo lung counts on selected personnel or about using alternative urine sampling times
and ~~soci11ted actio~ level!; computed 1.1$1-ng NURE.G-0874.
cUnleiiS rhe restdt WliS ;~micipated and ClluSed by ~:onditions already co~rccted.
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 1 of 15

2.0 RADIATION MONITORING – AREA

2.1 HIGH VOLUME AIRBORNE AREA AIR SAMPLING

Area air sampling involves passing a representative sample of air through a filter paper
disc via an air pump for the purpose of determining the concentration of uranium in
breathing air at that location. Although the process is only measuring airborne
concentrations at a specific place and at a specific time, the results can often be used to
represent average concentration in a general area. A high volume sampler or similar high
volume pump will be used for this purpose. Samples will be analyzed as per standard
gross alpha analysis procedures using a sensitive alpha detector.

2.1.1 Equipment

Monitoring equipment will be capable of obtaining an air sample flow rate of 40 lpm or
greater for one hour or longer. A variety of equipment may be used for area air sampling,
however normally the equipment used is an Eberline RAS-1, Scientific Industries Model
H25004, or equivalent. Equipment is calibrated prior to each usage as per Section 3.6
of this manual.

2.1.2 Frequency/Locations

Area dust monitoring frequency is monthly for the locations shown in Table 2.1.2-1.

Table 2.1.2-1
Airborne Radiation Sample Locations

Code Location/Description
BA1 Ore Scalehouse
BA2 Ore Storage
BA6 Sample Plant
BA7 SAG Mill Area
BA7A SAG Mill Control Room (radon only)
BA8 Leach Tank Area
BA9 Washing Circuit CCD Thickness
BA10 Solvent Extraction Building/Stripping Section
BA11 Solvent Extraction Building/Control Room
BA12 Yellowcake Precipitation & West Storage Area
BA12A North Yellowcake Dryer Enclosure
BA12B South Yellowcake Dryer Enclosure
BA13 Yellowcake Drying & Packaging Area
BA13A Yellowcake Packaging Enclosure
BA14 Packaged Yellowcake Storage Room
BA15 Metallurgical Laboratory Sample Preparation Room
BA16 Lunch Room Area (New Training Room)
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 2 of 15

Code Location/Description
BA17 Change Room
BA18 Administrative Building
BA19 Warehouse
BA20 Maintenance Shop
BA21 Boiler
BA22 Vanadium Panel
BA22A Vanadium Dryer
BA23 Filter Belt/Rotary Dryer
BA24 Tails
BA25 Central Control Room
BA26 Shifter’s Office
BA27 Operator’s Lunch Room
BA29 Filter Press
BA30 Truck Shop
BA31 Women’s Locker Room
BA32 Oxidation
BA33A AF South Pad
BA33B AF North Pad

Areas BA-10 and BA-12 are soluble uranium exposure areas. These areas are areas
where the uranium compounds that are produced are soluble in lung fluids and are
comparatively quickly eliminated from the body. All the other areas are insoluble
exposure areas. Insoluble uranium areas are areas where the uranium compounds are not
readily soluble in lung fluids and are retained by the body to a higher degree.
Temperature of drying operations has a significant impact on solubility of uranium
compounds. High drying temperatures produce insoluble uranium compounds. Area
uranium dust monitoring, during production periods, is weekly in the designated
yellowcake production areas. Monitoring increases to weekly in other monitored areas
with the observance of levels exceeding 25% of 10 CFR 20 limits and reverts to monthly
upon a continued observance of levels below 25% of 10 CFR 20 limits as determined by
the RSO. The RSO may also perform any additional samplings at his or her discretion.

The RSO will designate those areas involved in area monitoring during non-production
periods. Non-production period monitoring becomes effective one month following the
cessation of production.

2.1.3 Sampling Procedures

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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 3 of 15

1. A RAS-1 or similar high volume pump shall be used for area grab sampling. Insure
the pump has been recently calibrated within the past month.

2. The locations selected for area air samples should be representative of exposures to
employees working in the area.

3. For routine sampling, the sampling period should be for a minimum collection
duration of 60 minutes at a flow of 40 lpm or greater.

4. Insert a clean filter into the filter holder on the sampler. Note start time of pump and
record unusual mill operating conditions if they exist.

A. Stop sample collection and note time. Normally, an automatic timer is
connected to the sampler and a 1 hour sample collection time is used.

6. Remove the filter from the sampler and place in a clean glassine envelope or the
package supplied by the manufacturer for delivery to the Radiation Department.

7. Count the sample by gross alpha counting techniques and enter the result and
sampling information into the record.

2.1.4 Calculations

Perform calculations as specified in Section 4.0.

2.1.5 Records

Logs of all samples taken are filed in the Radiation Safety Officer’s files. Data is utilized
to calculate radiation exposures as specified in Section 4.0.

2.1.6 Quality Assurance

Calibration checks on each air sampler are made at least monthly to ensure accurate
airflow volumes are being collected. Usage of tweezers and new filter storage containers
minimizes contamination potential. Field logging of data during sampling and logging of
identifying data on sampled filter containers minimizes sample transposition. Samples
may periodically be submitted for chemical analysis and a comparison of these results to
the radiometric measurements will be made.

Review of data by the RSO and by the ALARA audit committee further assures quality
maintenance.

2.2 RADON PROGENY

2.2.1 Definitions
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 4 of 15

Working Level:

A. The exposure to 1.3E + 05 MEV of alpha energy or the potential alpha energy
in one liter of standard air containing 100 pCi each of RaA (Polonium-218), RaB
(Lead-214), RaC (Bismuth-214), and RaC prime (Polonium-214). (Exposure
level, not a dose rate)

Kusnetz Method: Method of radon progeny measurement and calculation based
upon a 10 liter sample and at least 40 minutes decay time before counting.

2.2.2 Equipment

The equipment utilized consists of the following, or appropriate equivalents:

 Portable personal sampler
 Gelman 25 mm filter holder with end cap, or equivalent
 Gelman Type A/E 25 mm diameter glass fiber filters, or equivalent
 Counter-Scaler – Eberline MS-3 with SPA-1 probe, or equivalent

2.2.3 Frequency/Location

Radon progeny samples are obtained monthly for only those locations occupied by
personnel where exposures may have the potential of exceeding 25% of 10 CFR 20
limits. The RSO shall so designate those areas to be monitored during non-production
periods.

2.2.4 Procedures

The procedures to be utilized are as follows:

1. Assemble filter trains.

2. Ensure pump batteries are fully charged.

3. Calibrate pump (see Section 3.5).

4. Attached filter trains at sample locations; disconnect end plug.

5. Collect sample in the breathing zone of the employee.

6. Collect sample for five minutes at 4.0 lpm.

7. Log sample site, time started, time stopped, and filter pump number prior to leaving
each site on the field log notebook.
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 5 of 15

8. Samples are counted between 40 minutes and 90 minutes after collection using
sensitive alpha detector.

9. Check the calibration and function check information to ensure the detector is
calibrated and operating.

10. If the calibration check correlates, proceed with sample analysis.

11. Radon progeny samples are normally counted for three minutes; however any sample
count time may be selected for counting.

12. Run background detector count prior to running sampled filters.

13. After counting, calculate working levels.

Equation: _______(CPM - Bkg)______
( eff) (20 liters) (Time Factor) = WL

Where: CPM - sample count per minute
Bkg - counter-detector background count per minute
 Efficiency - The efficiency of the counting system (See Section
3.2.3.3)
Time Factor - Values determined from Kusnetz method (See
attached Table 2.2.4-1)
WL - Working Levels

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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 6 of 15

TABLE 2.2.4-1
Time Factors

Min. Factor Min. Factor
40 150 71 89
41 148 72 87
42 146 73 85
43 144 74 84
44 142 75 83
45 140 76 82
46 138 77 81
47 136 78 78
48 134 79 76
49 132 80 75
50 130 81 74
51 128 82 73
52 126 83 71
53 124 84 69
54 122 85 68
55 120 86 66
56 118 87 65
57 116 88 63
58 114 89 61
59 112 90 60
60 110
61 108
62 106
63 104
64 102
65 100
66 98
67 96
68 94
69 92
70 90

2.2.5 Exposure Calculations

The personnel exposure calculations are a job-weighted average of those areas and
concentrations that an individual is exposed to. The procedure is:

1. Determine areas and durations (hrs.) each individual worked during the period
(month and quarter).

2. Determine monitored concentrations (WL) for each area so noted.
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 7 of 15

3. The multiplication of the hours worked in each area by the area concentration (WL)
noted is added to the result for each area involved in the period.

4. The result is the Working Level Hours exposed (WLH) for the period.

5. The working level hours (WLH) divided by 173 (30 CFR 57.5-40 note); or hours per
month gives the working level months (WLM) exposure. (The limit is 4 working
level months exposure per year.)

6. If calculated per quarter, the working level hours summed for the quarter are divided
by 519 (173 X 3) to obtain the working level quarter exposure.

See Section 4.0 for details on how to perform exposure calculations and maintain the
exposure records.

2.2.6 Records

Data records, which are filed in the Radiation Safety files, include:

1. Sample location
2. Date and time of sample
3. Time on and off of sample pump
4. Counts per minute of sample
5. Elapsed time after sampling
6. Background detector count
7. Appropriate Kusnetz time factor
8. Working level
9. Sampler identification

Employee exposure records include:

1. Month monitored
2. Areas and duration worked
3. Employee identification
4. Concentrations (WL) observed
5. Calculated WLMs

2.2.7 Quality Assurance

Calibration checks each month assure proper calibration of the counting equipment.
Documented semi-annual calibrations of the counting equipment using certified alpha
calibration and pulse meter sources ensure proper calibration of the equipment over the
anticipated ranges. The air sampling system has documented calibration prior to each
use, ensuring sampling the appropriate air volumes. Duplicate counts of select data may
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 8 of 15

be counted to assure instrument precision. Field documentation is maintained for each
sample during monitoring. This methodology provides assurance in data quality.

Review of data by the RSO and the ALARA audit committee further assures quality
maintenance.

2.3 ALPHA SURVEYS

2.3.1 Equipment

Equipment to be utilized in area alpha surveys is shown in Appendix 1. Pre-use function
checks will be performed on all radiation survey equipment as specified in Section
3.1.2.3.2.

2.3.2 Frequency/Locations

Fixed and removable alpha surveys are made at those general locations on the Table
2.3.2-1, “Alpha Area Survey Locations.” Surveys are completed weekly in those areas
designated by the RSO as authorized lunchroom/break areas are monitored. Designated
eating areas are listed in Table 2.3.2-2.

Table 2.3.2-1
White Mesa Mill
Alpha Area Survey Locations

Scale House Table
Warehouse Office Desks
Maintenance Office Desks
Change Room Lunch Tables
Maintenance Lunchroom Tables
Mill Office Lunchroom Tables
Metallurgical Laboratory Desks
Chemical Laboratory Desks
Administrative Break Room Counter
Administrative Office Desks

Table 2.3.2-2
White Mesa Mill
Designated Eating Area Locations

Maintenance Supervisor Break Room
Main Lunch/Training Room
Administrative Break/Conference Rooms
Administrative Office Desks
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 9 of 15

2.3.3 Procedures

2.3.3.1 Respirators

Respirators are monitored utilizing a removable alpha smear that is read using alpha
scaler meter such as a Ludlum Model 2200 or other equivalent radiological instruments.
Readings exceeding 100 dpm/100 cm2 result in re-cleaning or discarding of the
respirator. Respirator cleaning and monitoring is a function of the Radiation Safety staff
assigned to this duty. The meter’s performance is checked prior to each use period.

2.3.3.2 Fixed Alpha Surveys

Alpha surveys for fixed alpha contamination are performed using a variety of alpha
detecting instruments, as listed in Appendix 1. Each instrument is checked using a
calibrated alpha source for proper function and operation prior to use, as described in
Section 3.1.2.3.2.

Adjustments to the surface area being measured must be made to convert from the
particular detector’s surface area to the commonly used surface area of 100 cm2.
Therefore when converting a measurement to the commonly used unit of dpm/100 cm2, a
multiplying area factor must be applied to the measurement. For the Ludlum instrument
with a 43-1 detector of 75 cm2 surface, multiply the value by 1.33 (i.e. 100 cm2 divided
by 75 cm2).

The procedures are:

1. Turn the meter on and check the meter battery condition.

2. Check alpha detector mylar surface for pinholes, etc. Replace if necessary and repeat
calibration.

3. As specified in Section 3.1.2.3.2, perform a function calibration check using
calibrated alpha source.

4. If check is acceptable, proceed with monitoring.

5. At each designated site, monitor designated surfaces, table tops, etc., holding within
¼ inch of the surface.

6. Record data, location, cpm/cm2 monitored on data sheet.

7. At the conclusion of the survey, transpose results to the file log, correcting to
dpm/100 cm2, using correction for detector’s surface area and cpm/dpm conversion
factor.
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 10 of 15

2.3.3.3 Removable Alpha Surveys

The Ludlum Model 2200 scaler with 43-17 detector, or a variety of other sensitive alpha
detection instruments such as Model 2929 or equivalent, counts wipe samples collected
during removable alpha surveys. Glass fiber filters, sized to fit the detector sample slot,
are utilized as the wipe medium. A template having a 100 cm2 surface area maybe used
to standardize the surface area wiped.

The procedure is:

1. Perform function check calibration of the scaler/detector. Ensure that this
measurement is within ± 10% of the value obtained from the calibration laboratory.

2. If so proceed with the survey and counting.

3. Obtain clean filters and clean envelopes for filter storage.

4. At a location to be surveyed, remove the filter from the envelope and wipe the surface
covering approximately 100 cm2. This is easily accomplished by making an “S”
shaped smear for approximately 10 inches using normal swipes (approximately 2.5
cm diameter).

5. Record on envelope the date and location of the sample.

6. Upon returning to counting lab, place an unused filter in the counting unit for at least
1 minute and obtain a background count rate.

7. Repeat procedure for each used filter, extracting filter from envelope, immediately
prior to counting, using tweezers and placing in the detector slot with the wiped
surface facing the detector, and count for at least 1 minute.

8. Convert results from cpm/filter to dpm/filter (100 cm2 wiped) after subtracting the
blank background count.

9. Record on the alpha survey form the following information:

A. Sample location and conditions
B. Sample date
C. Sampler identification
D. Wipe count dpm/100 cm2

10. Discard the filters and envelopes

2.3.4 Action Limits
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 11 of 15

2.3.4.1 Respirators

Levels greater than 100 dpm/100 cm2 squared require re-cleaning or discarding of a
respirator.

2.3.4.2 Fixed Alpha Surveys

Levels greater than 1,000 dpm/100 cm2 squared require remedial action by management.
ALARA criterion ensures that the RSO takes action where necessary to maintain levels
as low as reasonably achievable.

2.3.4.3 2.3.4.3 Removable Alpha Surveys

Levels greater than 1,000 dpm/100 cm2 squared require remedial action and
decontamination. ALARA criteria ensure that the RSO takes action where necessary to
maintain levels as low as reasonably achievable.

2.3.5 Records

Records of fixed and removable alpha surveys are maintained in the Radiation Safety
office files. Records include:

1. Sample location/conditions
2. Sample date
3. Sampler identification
4. Fixed alpha determination – dpm/100 cm2
5. Removable alpha determination – dpm/100 cm2
6. Remedial action taken, where necessary

2.3.6 Quality Assurance

Calibration function checks of detector performance and visual observation of detector
surfaces prior to each survey ensures counting reliability and consistency. Usage of clean
containers and tweezers minimizes contamination of wipe samples. A Field log of
sample I.D.’s on sample containers minimizes transposition of samples. Data review by
the RSO and by the Audit Committee further assures quality maintenance.

2.4 BETA-GAMMA SURVEYS

2.4.1 Equipment

Beta/Gamma surveying instruments used for beta-gamma surveys are listed in Appendix
1 and the sources used are listed in Appendix 2.

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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 12 of 15

Some instruments read directly in mrem/hour while others read in cpm (with a
conversion to mrem/hour). The model 44-6 detector has a removable beta shield
allowing discrimination between beta and gamma contributions. Each instrument has a
manufactures user’s manual which describes the function, use and capability of each
instrument. These manuals must be understood before surveying proceeds. Calibration
of Beta/Gamma and functional checks are performed using calibrated Cs-137 or SrY 90
sources

2.4.2 Frequency/Locations

The sites noted on Table 2.4.2-1 are monitored on a monthly basis by of the Radiation
Safety staff during production periods. During non-production periods, only areas
routinely occupied by personnel are monitored as designated by the RSO.

Table 2.4.2-1
Beta-gamma Survey Locations

Identification Number
Description of Possible
Source of Area of Exposure

Distance from Source in cm
WM-1 Mill Feed Hopper & Transfer Chute 1
WM-2 SAG Mill Intake-Feed Chute 1
WM-3 Screens-Area Floor Between Screen 1
WM-4 Leach Operator’s Desk 1
WM-5 Leach Tank Vent #3 1
WM-6 Leach Tank #3 – Wall 1
WM-7 CCD Thickeners 1
WM-8 Pumphouse Tailings Discharge 1
WM-9 Oxidant Makeup Room-Sump Pump 1
WM-10 Shift Foreman’s Office-Work Desk 1
WM-11 SX Operator’s Area 1
WM-12 Precipitation Tanks #1 Tank; Wall 1
WM-13 Precipitation Section “Lab Bench” 1
WM-14 Precipitation Vent 1
WM-15 Yellowcake Thickener #1; Wall 1
WM-16 Centrifuge Discharge-Chute Wall 1
WM-17 Yellowcake Thickener #2; Wall 1
WM-18 Yellowcake Packaging Room 1
WM-19 Yellowcake Dryer 1
WM-20 Yellowcake Dust Collector 1
WM-21 SX Uranium Mixer #1 Extractor 1
WM-22 SX Uranium Mixer #1 Stripping 1
WM-23 SX Vanadium Mixer #1 Stripping 1
WM-24 Vanadium Dryer 1
WM-25 Mill Laboratory Fume Hood 1
WM-26 Chemical Laboratory Work Area 1
WM-27 Metallurgical Laboratory Work Area 1
WM-28 Lunchroom Eating Area 1
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 13 of 15

Identification Number
Description of Possible
Source of Area of Exposure

Distance from Source in cm
WM-29 Lunchroom Wash Area 1
WM-30 Maintenance Shop – Work Area 1
WM-31 Maintenance Shop – Rubber Coating 1
WM-32 Tailings Impoundment Discharge 1
WM-33 Tailings Impoundment Dike 1 1
WM-34 Tailings Impoundment Dike 2 1
WM-35 Tailings Impoundment Dike 3 1
WM-36 Scalehouse 1
WM-37 Tailings Impoundment Dike 4 1

2.4.3 Procedures

The monitoring procedures are:

1. Check meter battery condition.

2. Check detector using a check source.

3. If the calibration function check indicates that the instrument is operating within
calibration specifications, proceed with monitoring.

4. Survey each designated location on Table 2.4.2-1 and record in the field log:

A. Site location/condition
B. Date
C. Instrument used
D. Sampler’s initials
E. Meter reading (beta + gamma)
F. Meter reading (gamma)

5. Upon returning to the office, record the mrem/hr reading into a permanent file which
is maintained for beta-gamma exposure evaluation.

2.4.4 Action Levels

The ALARA concept is utilized in action levels. Responses include operative cleaning of
the area or isolation of the source. The Radiation Safety Department will ensure levels
ALARA.

2.4.5 Records

Records maintained in the Radiation Safety office files include:

1. Date monitored
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Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 14 of 15

2. Site location/condition
3. Instrument used
4. Sampler’s initials
5. Beta/Gamma level, mrem/hr
6. Remedial action taken, if necessary

2.4.6 Quality Assurance

Quality of data is maintained with routine calibration and individual function checks of
meter performance. Personnel utilizing equipment are trained in its usage. Records of
the operational checks and calibrations are maintained in the files. The RSO routinely
reviews the data and the ALARA audit committee periodically analyzes the performance
of the management of the monitoring and administrative programs.

2.5 EXTERNAL GAMMA MONITORING

External gamma area monitoring is conducted at various locations around the Mill site in
order to provide Radiation Safety Staff with area-specific gamma measurements. The
procedures applicable to such monitoring are set out in Section 4.3 of the Mill’s
Environmental Protection Manual.

2.6 EQUIPMENT RELEASE SURVEYS

2.6.1 Policy

Materials leaving a Restricted Area going to unrestricted areas for usage must meet
requirements of NRC guidance for “Decontamination of Facilities and Equipment Prior
to Release for Unrestricted Use” (dated May 1987).

All material originating within the restricted area will be considered contaminated until
checked by the Radiation Safety Department. All managers who desire to ship or release
material from the facility will inform the RSO of their desires. The RSO has the
authority to deny release of materials exceeding NRC guidance for “Decontamination of
Facilities and Equipment Prior to Release for Unrestricted Use” (dated May, 1987). No
equipment or materials will be released without documented release by the RSO or his
designee.

2.6.2 Limits

The release limits for unrestricted use of equipment and materials is contained in the
NRC guidance listed above in Section 2.6.1 and are summarized as follows:

Limits for Alpha emissions for U-Nat and its daughter products are:

Average 5,000 dpm/100 cm2
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 2 Page 15 of 15

Maximum 15,000 dpm/100 cm2
Removable 1,000 dpm/100 cm2

Limits for Beta-gamma emissions (measured at a distance of one centimeter) for
Beta/Gamma emitting radioisotopes are:

Average 0.2 mrem/hr or 5,000 dpm/100 cm2
Maximum 1.0 mrem/hr or 15,000 dpm/100 cm2

2.6.3 Equipment

Radiological survey instruments are listed in Appendix 1.

2.6.4 Procedures

Upon notification that materials are requested for release, the Radiation Safety
Department shall inspect and survey the material. Surveys include fixed and removable
alpha surveys and beta-gamma surveys. An equipment inspection and release form is to
be prepared and signed by the RSO or his designee. Any material released from the mill
will be accompanied with the appropriate release form. If contamination exceeds levels
found in NRC guidance “Decontamination of Facilities and Equipment Prior to Release
for Unrestricted Use”, dated May, 1987, then decontamination must proceed at the
direction of the RSO. If the material cannot be decontaminated, then it will not be
released.

2.6.5 Records

Documented records for each released item are filed in the Radiation Safety Department
files.

2.6.6 Quality Assurance

The RSO and the ALARA Audit Committee periodically review the policy and
documented release forms to ensure policy and regulatory compliance.
White Mesa Mill Weekly Alpha Survey 

Date: _________________________ 

Technician: _________________________ 

Alpha Survey Instruments 

Fixed       Removable 
Model #:      Model #:  
Serial #:      Serial #:  
Calibration:      Calibration:  
Efficiency:      Efficiency:  
Factor:      Factor:  
Background:      Background:  
MDA:       MDA:  

Notes: 
All fixed readings are in dpm/100 cm2 
T or t = Total or Fixed Alpha Reading in dpm/100 cm2 
R or r = Removable Alpha Reading per swipe or filter (approximately 100 cm2) 

RSO Reviewed:  
RSO Comments:  
EMPLOYEE SPOT ALPHA CONTAMINATION SURVEY  
DATE NAME BOOTS CLOTHES HANDS COMMENTS

Alpha Instrument Information: 
Instrument Model: __________________________________ 
Instrument SN: _____________________________________ 
Th230 Source SN: ___________________________________ 
DPM: __________________ CPM: _____________________ 
Efficiency: ______________ Efficiency Factor: ___________  
Administration Building 

Process Engineer
Office 
Balance 
Room 
Mass Spec
Room 
Chief Chemist 
Office 
Electrical 
Room 
Bioassay Room Training Room 
Sample Storage 
Room 
Mill Supt. 
Office 
Copy Room
Respirator 
Room 
Vault Safety Office Safety 
Office 
Bucking 
Room 
Metallurgist 
Office 
Women’s Restroom 
Closet 
Men’s Restroom
Office Conference Room Chief 
Metallurgist 
Office 
WMI 
Office 
Engineer’s 
Office Office Mill Manager’s Office Accounting 
Office 
Radiation 
Office Environmen
tal Office RSO Office 
Product Room Mass Spec 
Room 
Survey – Alpha 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2 
Chemical 
Laboratory 
Chemical Storage 
Metallurgical 
Laboratory 
Receptionist Area 
Coffee 
Area 
Waiting Area 
Cell #4B Project Trailers 

Table 
D
e
s
k 
Desk 
Desk 
De
s
k
Desk 
Survey –Alpha
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2 
Central Control Room 

Table
D
e
s
k 
Re
s
t
r
o
o
m

Desk
Table 
Co
n
t
r
o
l
 Pa
n
e
l
Table 
Survey – Alpha 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2 
Scalehouse 

Desk 
Table
Table 
Restroom 
Survey –Alpha 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2 
Change/Lunch Room 

 Table 
Table
Men’s Locker Room 
Women’s Locker Room 
Table
Lunch Room 
Laundry 
Room 
Shower 
Survey – Alpha
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2 
Maintenance and Warehouse Areas 

 Rubbering Room Pa
i
n
t
 Ro
o
m

Electrical ShopCarpenter Shop 
Elect. 
Foreman’s 
Office 
Re
s
t
r
o
o
m
Maintenance 
Foreman’s 
Office 
Warehous
e Office 
Re
s
t
r
o
o
m
Mech. 
Office 
Tool Room
Instrument 
Shop 
Warehouse 
Supply Office 

Operation 
Foreman’s 
Office 
Operation 
Foreman’s 
Office 
Maintenance 
Supt. Office 
Survey –Alpha
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in dpm/100 cm2
Monthly Beta‐Gamma Survey 

Date: _________________________ 

Technician: _________________________ 

Function Check of Survey Instrument 

Model #:       
Serial #:        
Calibration:        
Source:        
Source #:        
Reading mrem/hr:        
All units are in mrem/hr.        

RSO Reviewed:  
RSO Comments:  

Feedstock Areas 

Feedstock Source Reading 

Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Tails Area 

 Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Cell #1‐I
Cell #4‐B  
Cell #4‐A
Cell #3
Cell #2

SX Building 

Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Catch Basin/Sump
Uranium SX Circuit
Vanadium SX Circuit
Mini SX Circuit
Product Packaging Areas 

Yellowcake Packaging Enclosure
YC
 Pa
n
e
l

V2O5 
MCC 
V2O5 
Control 
Room 
V2O5 Packaging Area
Yellowcake Storage Area 
Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
SAG Mill/Leach Areas 

#1 
Leach 
#3 
Leach 
#5 
Leach 
#2 
Leach 
#4 
Leach 
#6 
Leach 
#7 
Leach 
W. Pre‐
Leach 
E. Pre‐
Leach 
#1 Pulp 
Storage 
#2 Pulp 
Storage 
#3 Pulp 
Storage 
Conveyor Belt From Grizzly to SAG Mill 
SAG Mill 
Survey –Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Old Shifter’s Office 
Old Operator’s Lunch Room 
Emergency Generator Building 

Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Emergency Generator
CCD/Precipitation Circuits 

#8 #3 #2 #1 
#7 #6 #5 #4 
#2 YC 
Precip
#1 YC 
Precip
Flocculant 
Mix
Flocculant 
Storage 
#1 Thickener #2 Thickener 
Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Uranium Packaging Circuit Upper Levels 

Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
North YC Dryer 
YC MCC 
South YC Dryer 
South YC Dryer 
YC Centrifuges 
North YC Dryer 
Administration Building 

Process Engineer
Office 
Balance 
Room 
Mass Spec
Room 
Chief Chemist 
Office 
Electrical 
Room 
Bioassay Room Training Room 
Sample Storage 
Room 
Mill Supt. 
Office 
Copy Room
Respirator 
Room 
Vault Safety Office Safety 
Office 
Bucking 
Room 
Metallurgist 
Office 
Women’s Restroom 
Closet 
Men’s Restroom
Office Conference Room Chief 
Metallurgist 
Office 
WMI 
Office 
Engineer’s 
Office Office Mill Manager’s Office Accounting 
Office 
Radiation 
Office Environmen
tal Office RSO Office 
Product Room Mass Spec 
Room 
Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Chemical 
Laboratory 
Chemical Storage 
Metallurgical 
Laboratory 
Receptionist Area 
Coffee 
Area 
Waiting Area 
Cell #4B Project Trailers 

Table 
D
e
s
k 
Desk 
Desk 
De
s
k
Desk 
Survey –Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Central Control Room 

Table
D
e
s
k 
Re
s
t
r
o
o
m

Desk
Table 
Co
n
t
r
o
l
 Pa
n
e
l
Table 
Survey – Beta/Gamma 
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Scalehouse 

Desk 
Table
Table 
Restroom 
Survey –Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Change/Lunch Room 

 Table 
Table
Men’s Locker Room 
Women’s Locker Room 
Table
Lunch Room 
Laundry 
Room 
Shower 
Survey – Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Alternate Feed Circuit 

108 
Feed 
Tank 
105 
107
102103106
110 
108B 111A 111B 112
114 
Oxidation 
#2 
Oxidation 
#1 
ADJ 
#1 
ADJ 
#2 
ADJ 
#3 
104
Filter 
Aid 
Fi
l
t
e
r
Pr
e
s
s
#2
Filter Press #1 
Barrel 
Dump 
Station 
Survey –Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr 
Maintenance and Warehouse Areas 

 Rubbering Room Pa
i
n
t
 Ro
o
m

Electrical ShopCarpenter Shop 
Elect. 
Foreman’s 
Office 
Re
s
t
r
o
o
m
Maintenance 
Foreman’s 
Office 
Warehous
e Office 
Re
s
t
r
o
o
m
Mech. 
Office 
Tool Room
Instrument 
Shop 
Warehouse 
Supply Office 

Operation 
Foreman’s 
Office 
Operation 
Foreman’s 
Office 
Maintenance 
Supt. Office 
Survey –Beta/Gamma
Date _______________ 
Inst. _______________ 
Cal Date ____________ 
SN _________________ 
Tech _______________ 
All units in mrem/hr
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 1 of 13

3.0 EQUIPMENT/CALIBRATION

All radiation detection instruments used at the Mill are sent to a qualified independent
laboratory for calibration every six months. If necessary, Radiation Safety Staff can use
the procedures outlined below to verify calibration.

3.1 Counters/Detectors

3.1.1 General

All radiation detectors require determination of detector optimal voltage performance or
plateau operating point. The graph of voltage applied to a detector versus detector
response is referred to as a plateau curve. The plateau curve typically has two rapidly
sloping sections and a stable, flat region. The optimal operating point is typically located
at the beginning of the flat, or flatter, section of the graph. The plateau curve is specific
for a particular detector and its accompanying readout, or measuring meter, and may vary
over time depending upon electronic component condition.

The equipment used to determine detector plateau curves includes:

1. Appropriate radiation sources
2. Electrostatic voltmeter
3. Radiation detecting instrument
4. Graph paper
5. Manufacturer’s technical manual

The procedure is:

1. Ensure instrument batteries are fresh or fully charged, if applicable.

2. Turn the instrument on.

3. Adjust the instrument voltage control starting at voltage of 600 using electrostatic
voltmeter to monitor voltage setting.

4. Expose detector to a radiation source applicable to the type of detector and in the
appropriate setting.

5. Record voltage and instrument response for each adjustment of voltage applied;
increments of 50 volts are adequate.

6. Repeat steps 4 and 5 until instrument response rapidly increases versus voltage level.
At this point, the detector is approaching potential differentials across the electrode
that may damage the detector.

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 2 of 13

7. Graph instrument response versus voltage applied.

8. Set equipment high voltage control to the optimum operating point. Record on graph
voltage selected.

9. Retain graph with calibration records.

3.1.2 Function Checks

Calibration function checks are required prior to use of radiation detection instruments
used at the Mill for the purpose of verifying that the instruments are operating at the same
efficiency as when they were calibrated by the calibration laboratory (i.e., within +/-
10%). Function checks are also used for verifying repeatability, reliability, and
comparability of an instrument’s measurements from one period to another. By
performing function checks for extended time periods, or on a larger sample size, these
goals are met.

Function checks involve two basic elements:

(1) The calibration laboratory efficiency is compared to the instrument’s efficiency
on the date of the function check; and
(2) The function check is verified with a check source having similar isotopic
composition as the one that was used by the calibration laboratory to calibrate the
instrument.

Function checks are made for all types of radiation survey instruments. The basic
principle in performing a function check is measuring the radiation field using a survey
instrument against a known amount of radiation from a calibrated source. These
measurements are made for the specific type of radiation occurring. For example, when
performing a beta/gamma survey, the instrument function check is performed using a
beta/gamma check source, such as a (SrY)-90. When performing an alpha survey, use an
alpha check source, such as Th-230 or Pu-239 for performing the function check.

Function checks are documented on the Calibration Check Forms (see Attachment A for
copies of forms to be used) for each specific instrument. They will be maintained in the
instrument's’ calibration and maintenance file.

A number of radiation detection instruments are used at the Mill. An Instrument Users
Manual for each instrument is maintained in the calibration files, together with
calibration documentation. The Users Manuals are to be considered the primary
reference for operating a particular instrument. This Standard Operating Procedure
(SOP) is not intended to replace the Users Manual, but rather to supplement the Manual
by providing steps to be performed for function checks. Before operating an instrument,
personnel should read the Users Manual and become familiar with the instrument’s
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 3 of 13

operation, capabilities, and special features. Personnel will also receive on the job
training on each instrument.

3.1.3 Alpha Monitors

Alpha particles travel very short distances in the air due to their high ionization ability –
typically ¼ to ½ inch. Due to this limitation, alpha monitoring must be done at a distance
of ¼ inch or less between the detector face and the source. Alpha monitoring, to be
consistent, requires ensuring a consistent distance be utilized between the detector face
and the source. Alpha detectors read out in counts per minute (cpm). A correlation
relationship, known as the efficiency factor, between the meter response and the actual
disintegration rate of the source is used to determine actual calibration of the meter.

Radioactivity is measured in curies (Ci), which, by definition, is 3.7 x 1010
disintegrations per second (dps), or 2.2 X 1012 disintegrations per minute (dpm). Another
measurement unit is the Becquerel, or one dps. Alpha radiation is usually monitored as
dpm, per surface area measured.

Radiation survey equipment used at the Mill for alpha surveys is listed in Appendices 1
and 2.

3.1.3.1 Calibration and Function Check Frequency

The frequency of calibration is specified in individual instrument user manuals and
manufacturer’s specifications.

During production periods, the following frequencies are observed for calibration and
function checks of radiation detection instruments:

Type
Calibration
Frequency
Function
Checks
1. Employee scans 6 month 5 days/week
2. Radon progeny 6 month each use
3. Respirator checks 6 month each use
4. Area fixed scans 6 month Daily or each use
5. Area wipe scans 6 month Daily or each use

During non-production periods, the following frequencies are observed:

Type
Calibration
Frequency
Function
Checks
1. Employee scans 6 month bi-monthly
2. Radon progeny 6 month each use
3. Respirator checks 6 month each use
4. Area fixed scans 6 month Daily or each use
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 4 of 13

5. Area wipe scans 6 month Daily or each use

3.1.3.2 Function Check Procedures – Alpha Counters and Scaler Instruments

The following steps will be used for function checks for alpha counters and alpha scaler
instruments.

1. Turn the instrument on and place a calibrated alpha check source in the detector
holder on or the face of the detector.

2. Count the source for 1 minute and record this value in cpm.

3. Repeat step 2 four more times.

4. Average the five readings and divide the average in cpm by the known activity on the
alpha source. This is the efficiency of the instrument and detector.

5. Compare this efficiency with the efficiency obtained from the calibration lab. If the
efficiency comparison is within ±10% deviation the instrument needs is calibrated if
not the instrument needs to be recalibrated.

6. If this efficiency comparison is within ±10% deviation the instrument is in
calibration.

7. Proceed with monitoring activities.

3.1.3.4 Calibration Procedures

All radiation detection instruments used at the Mill are sent to a qualified offsite
laboratory every six months for calibration. However, if additional onsite calibration is
required the calibration procedures are:

1. Set the detector high voltage at the prior determined operating point using an
electrostatic voltmeter.

2. For counter/scalers (radon progeny/wipes), close the detector, without source present,
obtain a reading for a set time. This is a background reading.

3. Place a calibrated source for the type of radiation being measured in the source holder
and obtain reading.

4. Observe the cpm for both the background and the source.
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 5 of 13

5. Subtract the cpm value of background from the cpm value of the source to obtain the
net cpm.

6. Divide the net cpm value by the known dpm of the source. This is the percentage
efficiency of the instrument system for this energy source.

7. By dividing 100 by this efficiency, an efficiency factor is obtained.

8. Dpm equals the cpm divided by the efficiency of the instrument detector system:

Note: 1 curie = 2.22 E + 12 dpm
1 microcurie = 2.22 E + 6 dpm
1 picocurie = 2.22 dpm

3.1.4 Beta-gamma Monitors

Equipment utilized for beta-gamma monitoring is listed in Appendices 1 and 2.

3.1.4.1 Function Check Procedure

The following steps will be used for function checks on beta/gamma instruments:

1. Turn the instrument on and place the calibrated beta/gamma (SrY-90) check source
on the face of the detector.

2. Let the reading stabilize to a constant value.

3. Record this value in cpm.

4. Divide this value by the known activity on the check source. This is the efficiency of
the instrument and detector.

5. Compare this efficiency to the efficiency obtained from the calibration laboratory. If
the efficiency comparison is within ±10% deviation the instrument needs is calibrated
if not the instrument needs to be recalibrated.

6. If this efficiency comparison is within ±10% deviation the instrument is in
calibration.

7. Proceed with monitoring activities.

3.1.4.2 Calibration

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 6 of 13

All beta-gamma survey instruments are sent out every six months for calibration.
Additional calibration, if necessary, may be performed on site using techniques described
in Reg. Guide 8.30, Appendix C – Beta Calibration of Survey Instruments for calibration
performed by a qualified calibration laboratory using the indicated source as listed in
Appendix 2.

3.1.5 Gamma Monitors

Instruments for gamma measurements are listed in Appendix 1.

3.1.5.1 Calibration

Independent calibration service laboratories perform calibration every six months.
Meters are calibrated to Cs-137 or other radioisotopes as suggested by the calibration
laboratory or manufacturer. Most calibration service laboratories calibrate Beta/Gamma
instruments electronically in accordance with their standard calibration procedures.
However, electronic calibration basically consists of the steps described below:

1. Connect survey instrument to be calibrated to the Model 500.

2. Turn both instruments on.

3. Record high voltage reading on Model 500.

4. Set cpm and the range multiplier on the Model 500 to the desired meter deflection.
The model 500 frequency controls consist of the three-digit readout, range selector,
coarse tuning knob, and the fine tuning knob. The three-digit readout is in cpm times
the frequency multiplier.

5. Calibrating survey instruments in cpm:

A. Set Model 500 frequency to value that will provide a ¾ meter deflection on the
survey instrument’s highest count scale. Set pulse height/amplitude to twice
instrument input sensitivity.

B. Adjust the range calibration potentiometer on the survey meter to provide correct
reading record.

C. De-code Model 500 frequency to next lower value; then do the same for the
survey instrument.

D. Adjust the range calibration potentiometer for correct reading on survey
instrument. Record readings.

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 7 of 13

E. Repeat process until all ranges have been calibrated at ¾ meter deflection.
Record readings.

F. Return to highest count scale on survey meter.

G. Set Model 500 for ¼ scale deflection readings.

H. Survey instrument should read within ± 10% of Model 500 frequency. Record
readings.

1) If readings are outside of the tolerance, re-calibrate for ¾ meter deflection.

2) Tap instrument meter lightly to check for sticky meter. Meter tolerance is
± 3% from the initial readings to the final reading.

I. Decode Model 500 to next lower scale. Check survey instruments for ¼ scale
reading. Record.

6. Record input sensitivity.

A. Select the most sensitive amplitude range 0-5 mv on the Model 500.

B. Observe meter on survey instrument.

C. Increase pulse amplitude, switching to next higher range, if necessary, until the
rate meter indicates a stable reading (i.e., further increase of pulse amplitude does
not cause an increase in meter reading). Now, decrease pulse height until the
survey instrument meter reading drops 15 ± 5%. Record this pulse height as the
instrument sensitivity.

D. If your instrument has a gain or threshold control to set instrument sensitivity, set
pulse height on the Model 500 to desired sensitivity level. Now adjust your
instrument threshold or gain control until the rate meter reading is within 85 ± 5%
of its stable reading value (see step C). Record the pulse height as instrument
sensitivity.

7. Calibrating survey instrument to cps.

A. Set frequency in Model 500. Divide the Model 500 readings by 60 to convert to
counts per second.

B. Repeat calibration steps as in item 5 above.

3.1.5.2 Frequency of Calibration

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 8 of 13

If electronic calibration is performed using the above method by the Radiation Safety
Department, the Model 500 pulse generator will be sent out for calibration on an annual
basis.

3.2 PERSONNEL AIR SAMPLERS

The calibration procedure for personnel air samplers involves one of three calibration
procedures. Samplers will be calibrated prior to each use by one of the three
methodologies: bubble tube, electronic or mass flow determinations. Air samplers may
be calibrated to standard air conditions.

3.2.1 Bubble Tube Calibration Method

The Bubble Tube Calibration Method is a calibration method and does not require
corrections to or from standard conditions for temperature and pressure. Personal air
samplers are calibrated for the flow rate for the sampling being performed, typically 2-4
lpm.

The equipment utilized is as follows:

1. Burette – 1,000 ml capacity, 10 ml divisions
2. Support, iron, rectangular base, with rod
3. Burette clamps – 2
4. Soap solution, dish
5. Tubing, Gelman filter holder, filter media (0.8 micron glass fiber Gelman type A/E)
6. Stopwatch
7. Small screwdriver
8. Sample pump

The procedures utilized are:

1. Assemble a filter train – place a filter in an in-line filter. Attach two lengths of tubing
to each connector of the in-line filter holder.

2. Make sure the Burette is clean. Clamp the 1,000 ml Burette upside down on the ring
stand with the Burette clamps.

3. Attach the pump to be calibrated to one end of the filter train, connect the other end
of the filter train to the small end of the 1,000 ml Burette, as per Figure 1.

4. Check all tubing connections for air tightness.

5. Pour approximately ½ inch (12 mm) of soap solution into the dish.

6. Start the pump.
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 9 of 13

7. Raise the dish up under the Burette opening, and then immediately lower the dish.
This should cause a film of soap to form over the Burette opening (i.e., a bubble).
Repeat this procedure until the film (bubble) will travel up the inverted Burette the
length of the graduation marks on the Burette without breaking.

8. When the film (bubble) has wetted the Burette inside and will travel the entire length
of the graduated area of the Burette, proceed with the actual calibration run.

9. Quickly form three bubbles and start the stopwatch when the middle bubble is at the
bottom graduation line (actually the 1,000 ml mark, but for purposes here, it will be
called the “zero” line).

10. Time the travel of the bubble from the zero line to the top line of the graduated
distance (0 ml). Since the capacity of the Burette is 1,000 ml (1.0 liter), then the
volume of air that is displaced above the bubble (i.e., needed to raise the bubble) is
1.0 liter. Stopping the stopwatch at the top mark is the time elapsed for the pump to
accomplish this. The rate of rise of the bubble through the apparatus is the flow rate
of air being pulled by the pump.

11. Increase or decrease the pump collection rate by adjusting the appropriate screw or
knob designed for this purpose.

12. Set the pump flow collection rate to the desired valued usually between 2 and 4 liters
per minute for low volume collection pumps and between 30 and 80 liters per minute
for high volume collection pumps.

3.2.2 Mass Flow Method

Mass flow meters are manufactured equipment designed to measure air collection flow
rates for a variety of purposes. Mass flow meters may be subject to temperature and
pressure corrections of air movement depending on whether they are
calibrated/manufactured for standard conditions.

Utilizing an air mass flow meter, traceable to NBS, the airflow rate of pumps can be
quickly adjusted to correct standard flow rate conditions. However, the mass flow meter
must be calibrated annually using a primary calibration method.

The equipment consists of the following:

1. Kurz air mass flow model 543 or equivalent
2. Suitable filter head adapter connections
3. Filter heads with filter media
4. Pump to be calibrated

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 10 of 13

Note: The meter is calibrated directly in standard air conditions – 25º C., 29.82” Hg.

The procedures utilized are:

1. Ensure pump batteries are fully charged.

2. Ensure flow meter batteries are fully charged.

3. Assemble filter train.

4. Connect (with a suitable adapter) the Kurz probe onto the filter train. Ensure an
airtight seal with tape, if necessary.

5. Set the meter function switch to the highest range: 40 std liters per minute.

6. Turn the pump on.

7. Select appropriate range on the meter. (Do not allow meter needle to be forcibly
pegged.)

8. Adjust the pump flow rate as necessary to desired flow rate. Allow the meter to
stabilize before adjustment of the pump.

9. Meter reads directly in standard air conditions, correcting for temperature and
barometric pressure.

Pump is now calibrated. Low volume pumps are set 4 lpm.

3.2.3 Electronic Calibration Method

The electronic calibration is the calibration method and does not require corrections to or
from standards conditions for temperature and pressure. Personal air samplers are
calibrated for the flow rate for the sampling being performed typically 2 – 4 lpm. Area
Airborne high volume air samplers should be calibrated to a minimum of 40 lpm.

The equipment utilized is as follows:

1. UltraFlo Primary Gas Flow Calibrator, or equivalent
2. Soap solution
3. Tubing
4. Small screwdriver
5. Sample pump

The procedure proceeds as follows:

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 11 of 13

1. Remove the two nipples on the back of the UltraFlo Primary Gas Flow Calibrator.
2. Attach the connection tubing from the top nipple to the sample pump.
3. Turn calibrator on.
4. Turn sample pump on.
5. Press the plunger style button on top of the soap dispensing portion of the device.
6. Write down the digital reading from the calibrator device.
7. Repeat steps 5 and 6 three times.
8. Take an average of the three readings.
9. If the sample pump requires adjustment, take the screwdriver and adjust the set
screw on the face of the sample pump and then repeat steps 5 through 7.
10. After the sample pump is calibrated, document the calibration on the Breathing
Zone/Radon or the High Volume Calibration Sheet depending on which device is
being calibrated, in the Radiation department.
11. Replace nipple caps on the back of the calibrator.

3.3 AREA AIR SAMPLERS

The calibration procedure for area air samplers involves one of the following procedures;
Kurz Mass Flow, Wet Test Gas Meter, Electronic or Bubble Tube Method.

3.3.1 Kurz Mass Flow Method

Repeat procedures discussed in 3.2.2 – except – airflow rate is adjusted to 40 slpm and
samplers utilized are:

1. Eberline RAS-1
2. Scientific Industries Model H25004
3. Equivalent

3.3.2 Wet Test Gas Meter Method

The wet test gas meter method utilizes a Precision Scientific wet test meter rated at one
cubic foot per revolution of the main dial. This method is used to calibrate the Kurz air
mass flow meter in addition to direct calibration of the area air samplers.

The procedures are:

1. Attached coupling to sampler filter assembly; secure it with tape.

2. Connect wet test meter hose to coupling.

3. Check water level of wet test meter. The needle should be on slightly above the
water level.

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 12 of 13

4. Check the thermometer temperature of the wet test meter. Record this on the
calibration sheet. Assume that the wet and dry bulb temperatures are the same.

5. Turn on the sampler. Check the west test meter’s manometer reading. This reading
is obtained by adding the left and right column values. (A typical reading might be
.3). Log these values for each ball height on the “Static pressure … H2O” column.

6. For the following sampler approximate settings, pull one cubic foot of air through the
wet test meter and record the time (in seconds) for each: 20, 30, 40, and 50 lpm.

Sampler Calibration Procedures – Calculations and Equations

1. To convert the static pressure (of the manometer attached to the wet test meter) from
inches of water to inches of mercury, divide the number of inches to water by 13.6.
Example: 0.4/13.6-0.02941176” Hg

2. To compute the actual flow rate (“Q rate act. lpm”), first divide the number of cubic
feet by the number of seconds. Example: 1 ft.3/90 sec = .01111 ft.3/awx. Convert
the cubic feet to liters. The conversion factor is 28.317. Example: .01111 ft.3/sec x
28.317 L ft.3 = .3146 L/sec. Multiply this by 60 to convert from seconds to minutes.
Example: .3146 L/sec x 60 sec = 1888 L/m or 18.88 lpm.

3. Using the “Vapor Pressures of Water” chart, find the vapor pressure inside the wet
test meter by matching the wet bulb temperature with the corresponding vapor
pressure. This number is the vapor pressure at the standard wet bulb (Pvpstw).

4. Find the vapor pressure at dewpoint using this formula: Pv dewpoint = Pvpstw =
0.0003613 (td-tw) Bp (Where +d = dry bulb temp; tw = wet bulb temp; bp =
barometric pressure in inches of mercury.) Assume that the dry bulb temperature
and the wet bulb temperature are the same, so the difference between them will
always be zero. Thus, Pv dewpoint will equal Pvpstw.

5. Determine the actual air density (D act) with this formula:

D act = 1.327
td + 459.67 [(Pg-Sp) - 0.378 (Pv dewpoint)]

(Where td - dry bulb temp in degrees F.; Bp = barometric pressure in inches of
mercury; Sp = static pressure of wet test meter in inches of mercury.)

White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 3 Page 13 of 13

Example:

D act = 1.327
70.5 + 459.67 [(24,8031 - 0.02941176) - 0.378 (.875)]

= 1.327 530.17 (24,773688 - 0.33075)

= (0.00250297) (24.442938)

D act = 0.06117996

Log this in “Air Density lbs/ft3” column of log sheet.

6. Find the flow rate of the sampler at standard conditions (Q std) using this formula:

Q std = Q act D act
D std

(Where D std = .075 lbs/ft3)

(i.e., Q std = 18.88 (0.06117996)
0.075

= 18.88 (0.8157328)

= 15.40

Q std = 15.40 (write this down for each position in the Q 0.075 column)

3.3.3 Bubble Tube Method

Refer to Section 3.2.1 to perform this method.

3.3.4 Electronic Calibration

Refer to Section 3.2.3 to perform this method.
White Mesa Mill – Standard Operating Procedures Date: 09/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 4 Page 1 of 12

4. EXPOSURE CALCULATIONS AND RECORD MAINTENANCE

4.1 PERSONNEL EXPOSURE CALCULATIONS

4.1.1 DACs for Conventional Ores

4.1.1.1 Solubility Classes

The solubility class, chemical form and abundance of conventional ores at the Mill, and
the resulting DACs to be used are as set out in the following table:

Table 4.1.1.1-1
Solubility Class, Chemical Form and Abundance of Conventional Ores

Location DAC U nat Th-230 Ra-226 Pb-210
Ore-Grind
6.00E-11 DAC is specified in 10 CFR Part 20
Leach 2.8E-10 ½ Ore,
½ Precipitation
½ Ore,
½ Precipitation
½ Ore,
½ Precipitation
½ Ore,
½ Precipitation
CCD 1.2E-11 Class D Class W 1 Class W 1 Class D 1
Sulfate Sulfate Sulfate Sulfate
25% 25% 25% 25%
SX 1.2E-11 Class D Class W 1 Class W 1 Class D 1
Sulfate Sulfate Sulfate Sulfate
25% 25% 25% 25%
Precipitation 5.00E-10 Class D 2
Diuranate NA NA NA
100%
Yellowcake
Packaging
2.20E-11 Class Y: 90 %
and Class W:
10 %

Oxide NA NA NA
100%
Tailings 1.70E-11 Class Y Class Y 2 Class W 1 Class W 1
Oxide Oxide Oxide Oxide
4% 32% 32% 32%

1 10 CFR Part 20, Appendix B
2 NUREG/CR-0530, PNL-2870, D.R. Kalkwarf, 1979, "Solubility Classifications of Airborne Products from Uranium Ores
and Tailings Piles”

White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 2 of 12

4.1.1.2 Application of Conventional Ore DACs to Workplace Locations

The Conventional Ore DACs will be applied as follows to the various locations in the
Mill site:

Table 4.1.1.2-1
Application of Conventional Ore DACs to Workplace Locations

Type of DAC DAC (µCi/ml) Individual Location
Ore/Grind 6.00E-11 Ore Scalehouse
Ore Storage
Maintenance Shop
Warehouse
Lunch Room
Change Room
Administration Bldg

Ore/Grind 6.00E-11 Dump Station
Ore/Grind 6.00E-11 SAG Mill
SAG Mill Control
Shifter's Office
Operations Lunch Room
Filter Press

Leach 2.80E-10 Leach Tank Area
CCD 1.20E-11 CCD Circuit Thickeners
SX 1.20E-11 SX Building South
Boiler
Ore/Grind 6.00E-11 Control Room
Yellowcake Precipitation 5.00E-10 YC Precipitation &Wet
Storage
Yellowcake Packaging 2.20E-11 North YC Dryer Encl.
South YC Dryer Encl.
YC Pkg Enclosure
YC Drying & Packaging
Area
Packaged YC Staging
Area
Tailings 1.70E-11 Truck Shop
Tailings
Yellowcake Precipitation 5.00E-10 Vanadium Circuit

White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 3 of 12

4.1.2 DACs for Mixtures

Both uranium ore and uranium mill tailings consist of a mixture of radionuclides each
with their individual DAC’s. Unless otherwise specified or determined in accordance
with Section 4.1.1 or 4.1.2 above, the DAC for a mixture is as follows:

4.1.2.1 Ore Prior to Leach

6E-11 µCi of gross alpha from U-238, U-234, Th-230, and Ra-226 per ml of air, or 3E-11
µCi of natural uranium per ml of air

4.1.2.2 Tailings When the Concentration of the Radionuclides in the Mixture is
Unknown

6E-12 µCi/ml = DAC for Th-230

4.1.2.3 Tailings or Other Mixture When the Identity and Concentration of Each
Radionuclide is Known

.The DAC for the mixture is calculated by the following (see Regulatory Guide 8.30,
page 2).
DACm =  f1 + f2 + … + fn -1
DAC1 DAC2 DACn

Where DACm = DAC for the mixture of radionuclides 1 through n.

DAC1 = DAC for the first radionuclide in the mixture.

DACn = DAC for the nth, the last, radionuclide in the mixture.

f1 = Fraction of alpha activity from the first radionuclide in
the mixture.

fn = Fraction of alpha activity from radionuclide n in the
mixture.

For example:

Ra-226 80 pCi/g DAC = 3E - 10 µCi/ml
Th-230 20 pCi/g DAC = 2E - 12 µCi/ml

White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 4 of 12

DACm = 80 + 20

 100 100  -1
3E-10 2E-12

=  2.67E9 + 1.00E11  -1

= 1
1.0E11

= 9.7E-12 µCi
ml

4.1.3 Sampling Time

Calculate the sampling time required to detect 10% of the DAC by solving for sampling
time in the following equation:

LLD
(Sampling Time) (Flow Rate = 0.1 DAC
of Sampler)

For example:

To detect 10% of the DAC for U-Nat, a 40 lpm air sampler would have to operate 57
minutes, assuming the sample counter has a lower level of detection of 10 dpm above
background, i.e.:

(10 DPM) ( pCi ) (E-6 µCi)
2.22 DPM pCi = 2E-12 µCi
(X min.) (40 lit) 103ml ml
min. lit

X = 56.8 minutes

4.1.4 Dose Calculations (10 CFR 20.1201-20.1202)

1. Analytical results of airborne particulate samples may be obtained in several different
units that need to be converted into mg soluble natural uranium to determine the
weekly exposures and into uCi-hr/ml or WL-hr to determine annual exposures. The
following table presents a summary of the conversions that may be necessary. The
first row of the table presents the operations to be performed in the conversions.
Enter the measured weight or activity, the sampler flow rate, the sampling time, and
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 5 of 12

the exposure time into the first four columns. Divide the values in column 1 by the
values in column 2 and column 3, and then multiply by the values in columns 4 and 5
to obtain the units in column 6, or:

(Column 1) (Column 4) (Column 5) = Column 6
(Column 2) (Column 3)

UNIT CONVERSION TABLE

1 2 3 4 5 6

OPERATION

DIVIDE

DIVIDE

MULTIPLY

MULTIPLY

ANSWER
MEASURED
VALUE
SAMPLER
FLOW RATE
SAMPLING
TIME
EXPOSURE
TIME
CONSTANT ANSWER
µg soluble
U-Nat
L/min min hrs 1.2 mg soluble
U-Nat
pCi soluble
U-Nat
L/min min hrs 1.77 mg soluble
U-Nat
pCi
gross alpha
L/min min hrs E-9 µCi-hrs
ML
µg
U-Nat
L/min min hrs 6.77E-10 µCi-hrs
ML
µCi
mL
Radon
--- --- hrs E7 WL-hrs
For example:

(10 µg Soluble U-Nat) (10 hrs) (1.2) = 2 mg Soluble U-Nat
(2 L/min) (30 min)

See notes for a description of the unit conversions.

2. The table on the following page is divided into four quadrants. Different quadrants
are for soluble uranium, insoluble uranium, tailings dust, and radon. Select the
proper quadrant for the type of airborne particulate being sampled. Enter the area,
particulate concentration, and hours of exposure in the labeled columns of the
selected quadrant.

3. The protection factors are whole numbers, e.g., 10, 50, 1,000. Divide 1 by the
protection factor and enter the quotient in the fourth column of each quadrant, e.g.,
for a protection factor of 1,000, enter 1/1,000 or 0.001 in the column. The 1/PF
values are unit-less.

4. Enter the product of the airborne concentration, the hours of exposure, the time, and
1/PF in the fifth column of each quadrant. Add these values and enter the total at the
bottom of the column.
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 6 of 12

5. On the dose calculations form which follows, enter the total for Soluble Uranium in
the equation and calculate the corresponding mg. If a value exceeds 10 mg, an over-
exposure may have occurred. If verified by a high uranium in urine results, an over-
exposure has probably occurred and needs to be reported to the NRC.

6. Enter the totals for Soluble Uranium, Insoluble Uranium, Tailings Dust, and Radon in
their respective equations. Perform the indicated calculations, add the fractions
together, and record as the subtotal. (Use the DAC for Th-230 or the DAC for
tailings dust to determine the contribution of tailings dust to the subtotal.) If a
subtotal exceeds 1, an over-exposure may have occurred. If verified by a high
uranium in urine result, an over-exposure has probably occurred and needs to be
reported to the NRC.

7. Enter the TLD determinations of whole body dose as the Deep Dose Equivalent on
the form. If the Deep Dose Equivalent exceeds 5 rems, an over-exposure may have
occurred and needs to be reported to the NRC.

8. If the Deep Dose Equivalent exceeds 0.5 rem and the subtotal exceeds 0.1, calculate
the Total Effective Dose Equivalent by adding the Deep Dose Equivalent to the
product of 5 rems times the subtotal and enter on the form. If the total effective dose
equivalent exceeds 5 rems, an over-exposure may have occurred and may have to be
reported to the NRC.

DOSE CALCULATIONS (10 CFR 20.1201 + 20.1202)

_________________ ______________ ____________ ______ ______
Name Soc. Sec. No. Co. I.D. No. Week Year

AREA SOL. U
µCi/ML
HR 1
PF
µCi-HR
ML
AREA INSOL. U
µCi/ML
HR 1
PF
µCi-HR
ML

TOTAL --- --- --- TOTAL --- --- --- ---
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 7 of 12

AREA TAILINGS
DUST
µCi/ML
HR 1
PF
µCi-HR
ML
AREA RADON
WL
HR 1
PF
WL-HR

TOTAL --- --- --- TOTAL --- --- ---

White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 8 of 12

DOSE CALCULATIONS (10 CFR 20.1201 + 20.1202)

________________ ______________ __________ _______ ________
Name Soc. Sec. No. Co. I.D. No. Week Year

Weekly Soluble (µCi-hr) (1.77E9) = _____________ mg
Uranium (mL)
Limit 10 mg

Annual Soluble ( µCi-hr)
Uranium mL = _____________
(2000 hr) (5E-10)

Annual Insoluble ( µCi-hr)
Uranium mL = _____________
(2000 hr) (2E-11)

Annual Tailings ( µCi-hr)
Dust mL = _____________
(2000 hr) ( *)

* = DAC for Th-230 = 6E-12;
or = DAC for tailings dust.

Annual Radon with ( WL-hr) = _____________
Daughters Present (2000 hr) (0.33 WL)
Subtotal _____________

Limit 1

Deep Dose Equivalent = TLD Whole Body Dose in rem = _____________ rem

Limit 5 rem
If the Deep Dose Equivalent is > 0.5 rem
and
the Subtotal is > 0.1, then

Total Effective = Deep + Committed Effective
Dose Equivalent Dose Equivalent Dose Equivalent

= ( rem) + (5 rem) ( Subtotal) = _____________ rem

Limit 5 rem
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 9 of 12

DOSE CALCULATIONS (10 CFR 20.1201 + 20.1202)

Notes:µ

1. PF = Respiratory Protection Factor.

2. The 10 mg soluble uranium per week limit in 10 CFR Part 20.1201 is more
restrictive than the (40 hour) (DAC) limit for natural uranium, thus compliance is
based on 10 mg per week.

3. The conversion of uCi-hr/mL to mg natural uranium is the product of:

(air concentration ) (hours of exposure) (breathing rate for light work)
(conversion of minutes to hours) (specific activity of natural uranium)
(conversion of ug to mg) which is:

(µCi-hr) (2E4 mL) (60 min) ( µg ) (E-3 mg) =
mL min hr 6.77E-7 µCi µg

(µCi-hr) (1.77E9)
mL = mg U-Nat

Thus to obtain mg natural uranium, multiply the µCi-hr/mL by 1.77E9.

4. Soluble Uranium DAC (Class D) = 5E-10 µCi/mL
Insoluble Uranium DAC (Class Y) = 2E-11 µCi/mL
Thorium-230 DAC (Class Y) = 6E-12 µCi/mL
Radon with Daughters DAC = 3E-8 µCi/mL = 0.33 WL
Tailings Dust DAC is a Site Specific Value = µ5. Description of
unit conversions:

a. ug soluble U-Nat  mg soluble U-Nat

( µg ) (E-3 mg) (60 min) (hr exposure) =
(L/min) (min sampler) (E3 mL) µg hr
L

( µg ) (hr exposure) (1.2) = mg soluble U-Nat
(L/min) (min sampler)

b. pCi soluble U-Nat  mg soluble U-Nat
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 10 of 12

( pCi ) (E-9 mCi) ( mg) (2E4 mL) 
(L/min) (min sampler) (E3 mL) pCi 6.77E-7 mCi min
L

(60 min) (hr exposure) =
hr

( pCi ) (hr exposure) (1.77) = mg soluble U-Nat
(L/min) (min sampler)

c. pCi gross alpha  µCi-hr

( pCi ) (E-6 µCi) (hr exposure) =
( L ) (min sampler) (E-3 mL) pCi
min L

( pCi ) (hr exposure) (E-9) = µCi-hr
( L ) (min sampler) mL
min

d. µg U-Nat  µCi- hr
mL

( µg ) (6.77E-7 µCi) ( hr exposure) =
( L ) (min sampler) (E3 mL) µg
min L

( µCi ) ( hr exposure) (6.77E-10) = µCi-hr
( L ) (min sampler) mL
min

e. µCi of Radon-222  WL
mL

(µCi) (E6 pCi) (E3 mL) (L-WL) =
mL µCi L E2 pCi

(µCi) (E7) = WL
mL

White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 11 of 12

4.2 Personnel Exposure Files

Denison Mines (USA) Corp. will generate and maintain individual exposure records for
each employee that works at the White Mesa Mill. The record system will be designed to
meet the specifications of the Federal Code of Regulations 10 CFR Part 20.

When an employee is hired, a file will be generated specifically for that individual. All
records that are to be in the radiation exposure file will be maintained during the term of
employment. When the employee terminates, all records will be preserved until the
Nuclear Regulatory Commission authorizes their disposition.

Personnel exposure records will be maintained at the mill site and will be accessible only
to the employee and the Radiation Protection staff. No copy of the exposure history will
be furnished to anyone outside of the Radiation Protection Department without a signed
consent form from the employee.

Contents of the exposure file:

Each personnel exposure file will contain the following records:

1. Information Sheet – Each information sheet will include the following information:

A. Employee’s full name
B. Birth date
C. Social Security number
D. Date of hire
E. Date of termination

2. Record of Urinalyses – A multiple entry log of all urinalyses conducted at this work
site will include the following information:

A. Employee’s full name
B. Sample dates
C. Sample identification number
D. Concentration of uranium in µg/l
E. An entry for any quality assurance “spikes” entered in µg/l

3. Internal personnel Exposure Records – These will be calculated and prepared using
the forms above or by the computer and the printout will be used as the permanent
record in the exposure file. The internal exposure records will contain the following
information:

A. Employee’s full name
B. Social Security number
White Mesa Mill – Standard Operating Procedures Date: 2/07 Revision: DUSA-1
SOP PBL-RP-4
Book: Radiation Protection Manual, Section 4 Page 12 of 12

C. Birth date
D. Exposure to airborne uranium expressed in both µCi and percent MPC
E. Any breathing zone samples collected for airborne uranium to be expressed in
µCi
F. Radon daughters expressed in working levels (WL) and period of exposure
(date)

4. External Exposure Record (OSL, Dosimeter) – The date received from the Dosimeter
contractor will be posted to the Dosimeter record in the exposure file. The following
information will be included on the Dosimeter record:

A. Employee’s full name
B. Birth date
C. Social Security number
D. Period of exposure (dates)
E. Exposure in millirems (mrem) for a given period
F. Total accumulated exposure while at the White Mesa Mill
G. Identification number of the Dosimeter badge

5. Record of Exposure from Previous Employment (NRC form 4 or similar) – A record
of occupational exposures that occurred prior to employment at the mill must be
obtained for each employee. If no such exposure record is available, the employee
must sign a statement to that affect. If previous exposure records were kept, a copy
must be secured and placed in the individual’s file.

6. Reports of Over-exposure – If an individual has been found to be over-exposed, the
Radiation Safety Officer will draft a letter of explanation. The report will explain the
circumstances and/or reasons for the over-exposure. It will also state any actions
taken to correct the problem or to prevent future over-exposures. The report must be
placed in the individual’s exposure file.

EMPLOYEE NAME:
WEEK BEGINNING:
AH.I::.A
BA 1 SCALEHOUSE
BA 2 ORE STORAGE
BA 7 SAG MILL
BAS LEACH
BA 9 CCD CIRCUIT
BA 10 SX BUILDING
BA 12 YC PRECIP
BA 12A N. YC DRYER ENG
BA 12B S. YC DRYER ENG
BA 13 YC PACKAGING
BA 13A YC PKG ENCL.
BA 15 BUCKING ROOM
BA 16 LUNCH ROOM
BA 17 CHANGE ROOM
BA 18 ADMIN. BLDG
BA 19 WAREHOUSE
BA 20 MAINT SHOP
BA21 BOILER
BA 22 VAN. PANEL
BA 22A VAN. DRYER
BA 23 VAN. BELT SCRN
BA 24 TAILINGS
BA 25 CONTROL ROOM
BA 26 MILL OFFICE
BA 27 OPER. LUNCH RM
BA 28 DUMP STATION
BA 29 FILTER PRESS
BA 30 TRUCK SHOP
EMPLOYEE SIGNATURE:
SUN
11U
MON
111
WEEK ENDING:
TUE WED THU
1/l 11:.:1 114
EXPOSURE TIME SHEET
FRI
1/5
SAT
1/(j
Total:
TOTAL
'
---
SUN
1/7
MON
11"
TUE
119
COMPANYID:
WED
1/1U
THU
1/11
FRI
11n
SAT
1/1::1
Total:
TOTAL
---
White Mesa Mill – Standard Operating Procedures Date: 9/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 5 Page 1 of 2

5. RADIATION WORK PERMITS

5.1 General

A Radiation Work Permit (“RWP”) system has been established for non-routine activities
where there is a potential for a significant radiation exposure, or for certain routine
activities where there is a potential to spread radioactive materials.

Specifically, an RWP is required for:

a) All non-routine maintenance work, or work for which there is no effective
operating procedure, which may, by the determination of the Radiation Safety
Officer, exceed 25% of the R313-15 limits;

b) All routine work, not covered by an operating procedure, that could involve
the spread of radioactive materials; and

c) The receipt, handling or processing of any alternate feed material or other
radioactive material, which has been determined by the Radiation Safety Officer,
not to fall within an existing operating procedure.

An RWP may also be used on a temporary basis for routine activities in lieu of an
operating procedure, while an operating procedure is being developed for the activity.

5.2 All Non-Routine Activities Require Radiation Safety Officer
Review

All non-routine activities require review by the Radiation Safety Officer. The Radiation
Safety Officer will advise the Mill Manager on a regular basis of any activities that
require an RWP.

5.3 Radiation Work Permit

The RWP is a form that describes the work to be performed, the location, duration and
personnel involved, and the radiological controls needed, such as respirator, urine
samples, breathing zone monitoring, time limitations for the activity, etc. The form must
also have an area for the Radiation Safety Officer, or his designee’s, signature. A copy of
a form of RWP is attached.

White Mesa Mill – Standard Operating Procedures Date: 9/11 Revision: DUSA-1
Book 20: Radiation Protection for Reclamation Activities, Section 5 Page 2 of 2
5.4 Procedure for Obtaining a Radiation Work Permit

The procedure for obtaining an RWP is:

a) When RWP-type work is to be performed, the Shift Foreman, Maintenance
Superintendent or other supervisory personnel shall complete the top portion of
the RWP, which will provide information on the specific work locations,
estimated work duration, type of work to be performed, and personnel utilized,
and present it to the Radiation Safety Officer;

b) The Radiation Safety Officer will indicate the radiological controls needed
based on the information given and the safety of personnel. The Radiation Safety
Officer or his designee will provide the necessary surveillance and respiratory
protection equipment;

c) No work can be performed until the Radiation Safety Officer or his designee
has approved the RWP;

d) Any maintenance or RWP jobs done in the yellowcake dryer or packaging
enclosures will require a member of the Radiation Staff to be present for the
duration of the job;

e) All supervisors will be given training in and copies of the requirements for
using RWPs, with the permits remaining on file for five years; and

f) Any supervisor found to be knowingly and willfully violating these
procedures will be issued a written warning, and the situation will be reviewed by
appropriate management for remedial action.
Denison Mines (USA) Corp
RADIATION WORK PERMIT
RWP#
Requestor Date
Job Location Rad Tech
Job Description
Radiological Monitoring and Sampling
At Start Intermitte Continuous At End Personnel leaving
(A) Dust (B) Radon Daughters (C) Beta-Gamma
(D) Gross Alpha (E) Removable Alpha
Breathing Zone# Minutes Ran pCi
Bioassay Yes No
Protective Equipment
Rubber Gloves Rubber boots Rubber suits
Coveralls Hoods Local Ventilation
Respirator Fit Testing
Irritant Smoke Size Worn
ALARA Considerations
Estimated Job Duration: Number of Workers
Standby Workers Showers Required Time Limitations
Cleanup
Estimated exposure
APPROVED BY: Date
Name In Out In Out In Out In Out
Job Status: Completed Changed Cancelled
Permit Terminated Date Time By
Reviewed By Date
Total Time
Name Proper Fit Fitted by (Initials)
Authorized Signature
Type1/2 full
APPENDIX 1
Denison Mines (USA) Corp.
White Mesa Mill Radiation Detection Instrument List
Model Serial Number
Type of Radiation Monitored with 
Instrument
Model 177 41298 Alpha
Model 177 116481 Alpha
Model 177 41261 Alpha
Model 177 12970 Alpha
Model 177 159117 Alpha
Model 177 159170 Alpha
Model 177 189581 Alpha
Model 177 185035 Alpha
Model 177 264740 Alpha
Model 177 264743 Alpha
Model 177 264616 Alpha
Model 177 159172 Alpha
Model 177 264571 Alpha
Model 177 247816 Alpha
Model 3 12658 Beta/Gamma
Model 3 12661 Beta/Gamma
Model 3 164493 Beta/Gamma
Model 3 158587 Alpha
Model 3 235288 Alpha/Beta/Gamma
Model 3 158588 Alpha
Model 3 254802 Alpha
Model 3 266392 Alpha
Model 3 254799 Alpha/Beta/Gamma
Model 3 257131 Alpha
Model 3 266292 Alpha
Model 3 237483 Alpha
Model 3 257120 Alpha
Model 2 12859 Beta/Gamma
Model 2929 146781 Alpha/Beta/Gamma
Model 2200 17534 Alpha
Model 19 160104 Beta/Gamma
Model 3030 265992 Alpha/Beta/Gamma
Model 19 253133 Beta/Gamma
Source Type
Beta/Gamma
Beta/Gamma
Beta/Gamma
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Alpha
Beta
Beta
Beta/Gamma
Beta/Gamma
Beta/Gamma
Beta/Gamma
Beta/Gamma
Alpha
Alpha/Beta/Gamma
Alpha/Beta/Gamma
Alpha/Beta/Gamma
2,150
18,000
234 mr/hr
8uCi
8uCi
8uCi
38,000
S-2350
Cesium-137
CS-7A #2
0.72 uCi
DPM or uCi
39,300
12,600
3,580
11,600
15,500
11693
1121/89
C. S. 2039
1121/89Uranium-238
Uranium-238
Uranium-238
Thorium-230
Thorium-230
Technetium-99
Cesium-137
Plutonium-239
Cesium-137
Denison Mines (USA) Corp.
White Mesa Mill Radiation Detection Instrument
Check Source List
11694
1856/90
StrontiumYttrium-90
Thorium-230
Thorium-230
Thorium-230
APPENDIX 2
Cesium-137 S-2044 1.656 uCi
Isotope Source Serial No.
98SR4700903
5995-09
CS-7A #3
Cesium-137
Thorium-230
Thorium-230
Thorium-230
10810 NA
NA
1,630
S-2349 16,700
11056
10811
11693
11251
234 mr/hr
33,0005994-09
234 mr/hr
CS-7A #1
S-2351
1121/89
NA
NA
Technetium-99 NA 0.042 uCi
Thorium-230
Thorium-230
Thorium-230
Thorium-230
10810
StrontiumYttrium-90 NA 0.0206 uCi
StrontiumYttrium-90 C9050 NA