ASTM C1561-10(2016)

Standard Guide for Determination of Plutonium and Neptunium in Uranium Hexafluoride and U-Rich Matrix by Alpha Spectrometry

SIGNIFICANCE AND USE
5.1 The method is applicable to the analysis of materials to demonstrate compliance with the specifications set forth in Specifications C787 and C996.  
5.2 The method can be used to quantify Pu and Np in U-rich matrix before to recycle them.
SCOPE
1.1 This method covers the determination of plutonium and neptunium isotopes in uranium hexafluoride by alpha spectroscopy. The method can also be applicable to any matrix that may be converted to a nitric acid system.  
1.2 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 requirements prior to use.

General Information

• Status: Published
• Publication Date: 31-May-2016
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

Relations

• Replaces: ASTM C1561-10 - Standard Guide for Determination of Plutonium and Neptunium in Uranium Hexafluoride by Alpha Spectrometry
• Effective Date: 01-Jun-2016
• Refers: ASTM C996-20 - Standard Specification for Uranium Hexafluoride Enriched to Less Than 5&#x2009;%&#x2009;<sup > 235</sup>U
• Effective Date: 01-Mar-2020
• Refers: ASTM C787-20 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Mar-2020
• Refers: ASTM C1475-17 - Standard Guide for Determination of Neptunium-237 in Soil
• Effective Date: 01-Jun-2017
• Refers: ASTM C787-15 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Jul-2015
• Refers: ASTM C996-15 - Standard Specification for Uranium Hexafluoride Enriched to Less Than 5 % ²³⁵U
• Effective Date: 01-Jul-2015
• Refers: ASTM D3084-05(2012) - Standard Practice for Alpha-Particle Spectrometry of Water
• Effective Date: 01-Jun-2012
• Refers: ASTM C787-11 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Jun-2011
• Refers: ASTM D3648-04(2011) - Standard Practices for the Measurement of Radioactivity
• Effective Date: 01-Jan-2011
• Refers: ASTM C996-10 - Standard Specification for Uranium Hexafluoride Enriched to Less Than 5 % ²³⁵U
• Effective Date: 01-Oct-2010
• Refers: ASTM C1475-05(2010)e1 - Standard Guide for Determination of Neptunium-237 in Soil
• Effective Date: 01-Jun-2010
• Refers: ASTM C1163-08 - Standard Practice for Mounting Actinides for Alpha Spectrometry Using Neodymium Fluoride
• Effective Date: 15-Jul-2008
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM C787-06 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Jan-2006
• Refers: ASTM C1475-05 - Standard Guide for Determination of Neptunium-237 in Soil
• Effective Date: 01-Jun-2005

Overview

ASTM C1561-10(2016), titled Standard Guide for Determination of Plutonium and Neptunium in Uranium Hexafluoride and U-Rich Matrix by Alpha Spectrometry, provides comprehensive guidance for analyzing plutonium (Pu) and neptunium (Np) isotopes in uranium hexafluoride (UF₆) and other uranium-rich matrices. Published by ASTM International, this standard is especially relevant for nuclear material testing laboratories, regulatory compliance, and nuclear fuel cycle management.

The method utilizes alpha spectrometry to identify and quantify plutonium and neptunium, ensuring that materials meet the specifications outlined in ASTM C787 and C996 for uranium hexafluoride. Moreover, it offers procedures applicable to matrices convertible to a nitric acid system, enhancing its flexibility for various sample types in nuclear quality assurance.

Key Topics

• Purpose and Scope:

  • Determination of plutonium and neptunium isotopes in uranium hexafluoride and uranium-rich matrices using alpha spectrometry.
  • Applicable to matrices that can be processed into a nitric acid solution.

• Analytical Process Overview:

  • Conversion of hydrolyzed uranium hexafluoride to an oxalic acid-nitric acid system.
  • Sequential removal of uranium and purification of plutonium and neptunium via solid-phase extraction.
  • Co-precipitation with neodymium as fluorides, followed by alpha spectrometric counting.

• Significance and Use:

  • Ensures nuclear material compliance with critical ASTM specifications.
  • Supports quantification of Pu and Np for material recycling and waste minimization in the nuclear industry.

• Tracer and Quality Control:

  • Use of Pu tracers to monitor recovery and analytical accuracy.
  • Recommendations for handling interferences, blanks, and calibration for reliable low-level radionuclide detection.

Applications

• Nuclear Fuel Cycle:
  Facilitates the monitoring and verification of uranium hexafluoride (UF₆) for enrichment and recycling processes. Analytical results using this method help demonstrate compliance with regulatory requirements, supporting safe handling and reuse of nuclear materials.

• Regulatory Compliance Testing: Laboratories employ this guide to meet criteria defined in ASTM C787 (specification for uranium hexafluoride for enrichment) and ASTM C996 (specification for low-enriched UF₆). It is integral for ensuring that produced or recycled materials conform to quality and safety standards.

• Environmental and Decommissioning Analysis: Adaptable for use on samples that can be converted to a nitric acid system, making it valuable for environmental monitoring, legacy site assessments, and nuclear facility decommissioning.

• Quality Assurance in Radioanalytical Laboratories: The guide's procedures enhance the reliability and reproducibility of plutonium and neptunium measurements, supporting robust laboratory management and reporting.

Related Standards

• ASTM C787 - Specification for Uranium Hexafluoride for Enrichment
• ASTM C996 - Specification for Uranium Hexafluoride Enriched to Less Than 5% U-235
• ASTM C1163 - Practice for Mounting Actinides for Alpha Spectrometry Using Neodymium Fluoride
• ASTM C1475 - Guide for Determination of Neptunium-237 in Soil
• ASTM D3084 - Practice for Alpha-Particle Spectrometry of Water
• ASTM D3648 - Practices for the Measurement of Radioactivity
• ASTM D1193 - Specification for Reagent Water

Practical Value

The ASTM C1561-10(2016) standard provides a robust and validated method for nuclear laboratories to accurately determine trace levels of plutonium and neptunium in uranium hexafluoride and similar matrices. Its application ensures regulatory compliance, quality control, and supports the safe management and recycling of nuclear materials. By using alpha spectrometry in accordance with this guide, organizations can maintain high standards of material verification, prevent false positives, and contribute to sustainable fuel cycle practices in the nuclear industry.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:C1561 −10 (Reapproved 2016)
Standard Guide for
Determination of Plutonium and Neptunium in Uranium
Hexafluoride and U-Rich Matrix by Alpha Spectrometry
This standard is issued under the fixed designation C1561; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Test Method
1.1 This method covers the determination of plutonium and 4.1 An aliquot of hydrolyzed uranium hexafluoride equiva-
lenttoapproximately0.5gofuraniumisconvertedtoanoxalic
neptunium isotopes in uranium hexafluoride by alpha spectros-
copy.Themethodcanalsobeapplicabletoanymatrixthatmay acid-nitric acid system and the uranium is selectively removed
be converted to a nitric acid system. via solid phase extraction. Plutonium and neptunium are
further purified by additional solid phase extractions. The
1.2 This standard does not purport to address all of the
plutonium and neptunium are then co-precipitated with neo-
safety concerns, if any, associated with its use. It is the
dymium as the fluorides and counted by alpha spectrometry.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.2 Tracer recoveries using this method are typically be-
bility of regulatory requirements prior to use. tween 75 and 90 % for uranium hexafluoride, for different
matrix (with impurities): ~ 10 %.The resolution of the tracer is
2. Referenced Documents typically less than 40 keV full-width at half-maximum.
2.1 ASTM Standards: 4.3 The minimum detectable activity will vary with tracer
recovery, sample size, instrument background, and counting
C787 Specification for Uranium Hexafluoride for Enrich-
ment efficiency.
C996 Specification for Uranium Hexafluoride Enriched to
Less Than 5 % U 5. Significance and Use
C1163 Practice for MountingActinides forAlpha Spectrom-
5.1 The method is applicable to the analysis of materials to
etry Using Neodymium Fluoride
demonstrate compliance with the specifications set forth in
C1475 Guide for Determination of Neptunium-237 in Soil
Specifications C787 and C996.
D1193 Specification for Reagent Water
D3084 Practice for Alpha-Particle Spectrometry of Water 5.2 ThemethodcanbeusedtoquantifyPuandNpinU-rich
D3648 Practices for the Measurement of Radioactivity matrix before to recycle them.
3. Terminology 6. Interferences
3.1 reagent blank—DI water processed the same as the
6.1 Incomplete removal of U-234 from the neptunium
samples; used in the determination of the minimum detectable
fraction could result in a false positive for the Np-237 analysis.
activity.
The method has been shown to adequately remove uranium at
enrichments up to 5 %. If the method is used for the analysis of
3.2 region-of-interest (ROI)—the channels, or region, in the
materials at greater than 5 % enrichment, a blank consisting of
alpha spectra in which the counts due to a specific radioisotope
uranium at the same enrichment as the samples should be
appear on a functioning calibrated alpha spectrometry system.
analyzed to show adequate removal of the U-234.
6.2 APu tracer is used to monitor the chemical recovery of
the Np. Spiked analyses should be performed to confirm the
This guide is under the jurisdiction ofASTM Committee C26 on Nuclear Fuel
Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test. appropriateness of this correction; fractionation of Np and Pu
CurrenteditionapprovedJune1,2016.PublishedJuly2016.Originallyapproved
during the separation could lead to incorrect test results.
in 2003. Last previous edition approved in 2010 as C1561 – 10. DOI: 10.1520/
C1561-10R16.
7. Instrumentation
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
7.1 Alpha Spectrometry System—See Practices D3084 and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. D3648 for a description of the apparatus.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1561−10 (2016)
8. Apparatus 9.17 Nitric Acid (2M)—Add 125 mL of concentrated nitric
acid to 500 mL of water; dilute to a final volume of 1 L.
8.1 Ion Exchange Columns, able to hold a 10 mL resin bed
and 15 mL solution washes.
9.18 Oxalic Acid in 1M HCl(0.1M)—Dissolve12.6goxalic
acid dihydrate in 500 mL of 1M HCl; dilute to a final volume
8.2 Filter Paper, 0.1 µm pore size, 25-mm diameter, com-
of 1 L with 1M HCl.
patible with HF.
9.19 Oxalic Acid in 2M HNO (0.1M)—Dissolve 12.6 g
9. Reagents and Materials
oxalic acid dihydrate in 500 mL of 2M HNO ; dilute to a final
9.1 Purity of Reagents—Reagent grade chemicals shall be
volume of 1 L with 2M HNO .
used in all tests. Unless otherwise indicated, it is intended that
9.20 Pu-236 or Pu-242 Tracer, traceable to a national or
all reagents shall conform to the specifications of the Commit-
international standard.
tee onAnalytical Reagents of theAmerican Chemical Society,
9.21 Sodium Nitrite (100 mg/mL)—Dissolve 500 mg
where such specifications are available.
NaNO in 5 mL water. Prepare fresh when using.
9.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water as defined 9.22 Extraction Chromatography Resin, containing
octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide
in Specification D1193.
(CMPO) dissolved in tri-n-butyl phosphate (TBP) as the
9.3 Ammonium Oxalate (0.1M)—Dissolve 12.4 g ammo-
5,6
immobilized extractant.
nium oxalate in approximately 500 mL of water and dilute to
1L. 9.23 Extraction Chromatography Resin, containing diamyl
7,8
amylphosphonate (DAAP) as the immobilized extractant.
9.4 Ascorbic Acid Solution (Saturated)—Add ascorbic acid
to 2M nitric acid while stirring until no more ascorbic acid will
10. Calibration and Standardization
dissolve. Prepare fresh when needed for use.
10.1 The alpha spectrometry units should be calibrated for
9.5 Ethanol, ethyl alcohol, absolute (200 proof), denatured.
energy, resolution and efficiency according to the manufactur-
9.6 Hydrochloric Acid (HCl), specific gravity 1.19, concen-
ers instructions. The background counting rate for the instru-
trated.
ment should be measured at a frequency determined by the
9.7 Hydrochloric Acid, 9M—Add 750 mLconcentrated HCl user. See Practices D3084 and D3648 for additional informa-
to 100 mL of water, dilute to a final volume of 1 L.
tion.
9.8 Hydrochloric Acid, 4M—Add 333 mL of concentrated
11. Procedure
HCl to 500 mL of water; dilute to a final volume of 1 L.
11.1 Uranium Removal:
9.9 Hydrochloric Acid, 1.5M—Add 125 mLof concentrated
11.1.1 Pipette an aliquot of hydrolyzed UF sample equiva-
HCl to 500 mL of water; dilute to a final volume of 1 L. 6
lent to 0.05 to 0.5 g uranium into a beaker. Add the Pu tracer
9.10 Hydrochloric Acid, 1M—Add 83 mL of concentrated
to the sample and evaporate to dryness. Add 10 mL concen-
HCl to 500 mL of water; dilute to a final volume of 1 L.
trated nitric acid and evaporate to dryness. This operation may
9.11 Hydrofluoric Acid (HF), concentrated HF, minimum
be repeated to remove fluoride. Option: Neptunium-239 can be
assay 48 %.
added as an independent tracer for the Np-237; see Guide
C1475 for its use.
9.12 Iron (III) Nitrate (10 mg Fe/mL)—Dissolve 18.0 g of
11.1.2 Prepare 2 DAAP extraction columns per sample by
Fe(NO ) ·9H O in 250 mL of water.
3 3 2
addingresinslurriedinwatertothecolumn.Allowthewaterto
9.13 Neodymium Chloride (10 mg Nd/mL)—Add 25 mL
drain to obtain a 10 mLbed volume. Condition the columns by
concentrated HCl to 1.17 g neodymium oxide and heat at
adding 15 mL of the oxalic acid in 2M nitric acid solution.
100°C until dissolved.Allow solution to cool and dilute to 100
Allow the solution to pass through the columns.
mL with water.
11.1.3 Dissolve the sample residue in the beaker above by
9.14 Neodymium Chloride (100 µg Nd/mL)—Dilute 1 mLof
adding15mLoftheoxalicacidin2Mni
...