ASTM C1000-00
(Test Method)Standard Test Method for Radiochemical Determination of Uranium Isotopes in Soil by Alpha Spectrometry
Standard Test Method for Radiochemical Determination of Uranium Isotopes in Soil by Alpha Spectrometry
SCOPE
1.1 This test method covers the determination of uranium isotopes in soil.
1.2 The test method is designed to analyze 10 g of soil; however, the sample size may be varied to 50 g depending on the activity level. This test method may not be able to completely dissolve all forms of uranium in the soil matrix.
1.3 The lower limit of detection is dependent on count time, sample size, detector efficiency, background, and tracer yield. The chemical recovery averaged 78% in a single laboratory evaluation, and 66% in an interlaboratory collaborative study.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A specific precautionary statement is given in Section 10.
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Designation:C1000–00
Standard Test Method for
Radiochemical Determination of Uranium Isotopes in Soil by
Alpha Spectrometry
This standard is issued under the fixed designation C 1000; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope System of Units (SI): The Modern Metric System
1.1 This test method covers the determination of uranium
3. Summary of Test Method
isotopes in soil. This test method describes one acceptable
2 3.1 A soil sample with uranium-232 tracer added is heated
approach to the determination of uranium isotopes in soil.
to destroy organic matter and dissolved with a mixture of
1.2 The test method is designed to analyze 10 g of soil;
hydrofluoric acid and nitric acid.The uranium is coprecipitated
however, the sample size may be varied to 50 g depending on
with ferric hydroxide and the precipitate is dissolved with
the activity level. This test method may not be able to
hydrochloricacid.Ironisremovedbyextractionwithisopropyl
completely dissolve all forms of uranium in the soil matrix.
ether, and plutonium, radium, and thorium are separated from
1.3 The lower limit of detection is dependent on count time,
uranium by anion exchange. Uranium is electrodeposited on a
sample size, detector efficiency, background, and tracer yield.
stainless steel disk and determined by alpha spectrometry. As
The chemical recovery averaged 78 % in a single laboratory
an option, the uranium may be prepared for alpha spectromet-
evaluation, and 66 % in an interlaboratory collaborative study.
ric measurement by using coprecipitation with neodynium
1.4 This standard does not purport to address all of the
fluoride.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Significance and Use
priate safety and health practices and determine the applica-
4.1 This test method is used to analyze soil for uranium
bility of regulatory limitations prior to use. A specific precau-
isotopes.Itcanbeusedtoestablishbaselineuraniumlevelsand
tionary statement is given in Section 10.
to monitor depositions from nuclear facilities.
2. Referenced Documents
5. Interferences
2.1 ASTM Standards:
5.1 Protactinium-231 may not be completely separated by
C 998 Practice for Sampling Surface Soil for Radionu-
3 the procedure and could interfere with the determination of
clides
uranium-233 or uranium-234 because it has the following
C 999 Practice for Soil Sample Preparation for the Deter-
3 alpha energies in MeV: 5.06, 5.03, 5.01, 4.95 and 4.73 (see
mination of Radionuclides
Appendix).
C 1163 Test Method for Mounting Actinides for Alpha
Spectrometry Using Neodymium Fluoride
6. Apparatus
D 1193 Specification for Reagent Water
6.1 Alpha Pulse Height Analysis System:
D 3084 Practice for Alpha-Particle Spectrometry of Water
6.1.1 A system consisting of a charged particle detector
D 3648 Practices for the Measurement of Radioactivity
capable of 50 keV or less resolution on samples electrodepos-
IEEE/ASTM SI-10 StandardfortheUseoftheInternational
ited on a flat mirror-finished stainless steel disk is required.
6.1.2 The resolution is defined as the width of an alpha peak
when the counts on either side of the peak are equal to one-half
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Test of the counts at the maximum of the peak (full width at half
Methods.
maximum height (FWHM)).
Current edition approved Aug. 10, 2000. Published September 2000. Originally
6.1.3 The counting efficiency of the system should be
published as C 1000 – 83. Last previous edition C 1000 – 90.
greater than 15 % and the background in the energy region of
Casella, V. A., Bishop, C. T., and Glosby, A. A., “Radiometric Method for the
Determination of Uranium in Soil andAir,” U.S. Environmental ProtectionAgency,
each peak should be less than 10 counts in 1,000 min.
EPA-600/7-80-019, Las Vegas, NV, February 1980.
Annual Book of ASTM Standards, Vol 12.01.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 11.02.
Annual Book of ASTM Standards, Vol 14.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1000
6.1.4 Aregular program of measurement control operations 7.12 Hydrochloric Acid (0.5 M)—Mix 42 mL of concen-
should be conducted for the alpha spectrometry system such as trated HCl with water and dilute to 1 L.
regular background checks, daily source check to determine 7.13 Hydrochloric Acid (1 M)—Mix 83 mLof concentrated
system stability, control charting, and careful handling of HCl with water and dilute to 1 L.
samples during changing. 7.14 Hydrochloric Acid (6 M)—Mix 500 mL of concen-
6.2 Electrodeposition Apparatus —A direct current power trated HCl with water and dilute to 1 L.
supply, 0 to 12 V and 0 to 2 A is required. A disposable 7.15 Hydrochloric Acid (8 M)—Mix 667 mL of concen-
electrodeposition cell is recommended. The cathode is a trated HCl with water and dilute to 1 L.
20-mm diameter stainless steel disk polished to a mirror finish 7.16 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
and the anode is a 1-mm diameter platinum wire with an 8-mm chloric acid (HCl).
diameter loop facing the cathode. 7.17 Hydrochloric Acid-Hydriodic Acid Solution (HCl-
6.3 Beakers and Covers (TFE-fluorocarbon), 250 mL. HI)—Mix 1 mL of concentrated HI with 50 mL of 6 M HCl.
6.4 Casserole (porcelain), 60 mL. Prepare immediately before use.
6.5 Centrifuge and Bottles, 250-mL capacity. 7.18 Hydrofluoric Acid (48 %)—Concentrated hydrofluoric
6.6 Ion Exchange Columns, 1.3 cm inside diameter by 15 acid (HF).
cm long with 100 mL reservoir. 7.19 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
6.7 Automatic Pipettes, 0.1 to 1.0 mL with disposable tips. (HNO ).
7.20 Sodium Hydrogen Sulfate (0.36 M in 1 M H SO )—
2 4
7. Reagents
Dissolve 10 g of NaHSO ·H O in 88 mLof water and add 112
4 2
mL of 1.8 M H SO .
7.1 Purity of Reagents—Reagent grade chemicals shall be 2 4
7.21 Sulfuric Acid (1.8 M)—Mix 100 mL of concentrated
used in all tests. Unless otherwise indicated, it is intended that
sulfuric acid with water and dilute to 1 L.
all reagents conform to the specifications of the Committee on
7.22 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
Analytical Reagents of theAmerican Chemical Society, where
(H SO )
such specifications are available. Other grades may be used, 2 4
7.23 Thymol Blue Indicator, Sodium Salt Solution (0.04 %).
provided it is first ascertained that the reagent is of sufficiently
7.24 Uranium-232, Standard Solution.
high purity to permit its use without lessening the accuracy of
7.25 Boric Acid.
the determination.
7.2 Purity of Water— Unless otherwise indicated, refer-
8. Sampling
ences to water shall be understood to mean reagent water as
8.1 Collect the sample in accordance with Practice C 998.
defined in Specification D 1193, Type III.
7.3 Reagent purity shall be such that the measured radioac- 8.2 Prepare the sample for analysis in accordance with
Practice C 999.
tivity of blank samples does not exceed the calculated probable
error of measurement.
7.4 Ammonium Hydroxide (0.15 M)—Mix 10 mL of con- 9. Calibration and Standardization
centrated ammonium hydroxide with water and dilute to 1 L.
9.1 If a standard uranium-232 solution is not available for
7.5 Ammonium Hydroxide (sp gr 0.90)—Carbonate-free,
use as a tracer, standardize a freshly prepared sample of
concentrated ammonium hydroxide (NH OH).
4 uranium-232; for guidance refer to Practices D 3648. This
7.6 Ammonium Sulfate Solution (1 M)—Dissolve 132 g of
standard may also be used to establish the counting efficiency
(NH ) SO in water and dilute to 1 L.
4 2 4 of the alpha spectrometer which then can be used to calculate
7.7 Anion Exchange Resin—Bio Rad AG1-X8, 100 to 200
the chemical recovery and lower limit of detection (LLD) of
mesh, chloride form or equivalent. Prepare a resin slurry by
the test method.
soaking the resin in 8M HCl and transfer the slurry to an ion
exchange column so that the resin column is approximately 10
10. Procedure
cm high.
NOTE 1—Precaution: Adequate laboratory facilities, such as fume
7.8 Electrolyte—Adjust the pH of 1 M (NH ) SO solution
4 2 4
hoods and controlled ventilation, along with safe techniques, must be used
to 3.5 with concentrated H SO and concentrated NH OH.
2 4 4
in this procedure. Extreme care should be exercised in using hydrofluoric
7.9 Ethyl Alcohol Solution, basic— Add 2 drops of 15 M
and other hot, concentrated acids. Use of rubber gloves is recommended.
NH OH to 100 mL of 95 % alcohol.
10.1 Acid Dissolution:
7.10 Ferric Chloride Solution (0.18 M in 0.5 M HCl)—
10.1.1 Weigh a 10 60.01 g soil sample into a casserole.
Dissolve 46 g of FeCl.6HOin0.5 M HCl and dilute to 1 L.
3 2
10.1.2 Add an appropriate amount of uranium-232 tracer to
7.11 Hydriodic Acid (48 %)—Concentrated hydriodic acid
the sample. (If the activity of the sample is expected to be less
(HI).
than 0.01 Bq/g or is unknown, add 0.1 Bq of tracer. For higher
levels add uranium-232 tracer which is equivalent to the
estimated activity of uranium in the sample.)
“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-
cal Soc., Washington, DC. For suggestions on the testing of reagents not listed by
theAmerican Chemical Society, see “Reagent Chemicals and Stan
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