ASTM C1514-08

Standard Test Method for Measurement of ²³⁵U Fraction Using Enrichment Meter Principle

SIGNIFICANCE AND USE
The enrichment meter principle provides a nondestructive measurement of the 235U fraction of uranium-bearing items. Sampling is not required and no waste is generated, minimizing exposure to hazardous materials and resulting in reduced sampling error.
This method relies on a fixed and controlled geometry. The uranium-bearing materials in the measured items and calibration reference materials used for calibration must fill the detector field of view.
Use of a low resolution detector (for example, NaI detector) to measure uranium with 235U fraction approximately 10 % which is contained in a thin-walled container can provide a rapid (typically 100 s), easily portable measurement system with precision of 0.6 % and bias of less than 1 %.
Use of a high resolution detector (for example, high-purity germanium) can provide measurement with a precision better than 0.2 % and a bias less than 1 % within a 300-s measurement time when measuring uranium with 235U fraction in the range of 0.711 % or above which is contained in thin-walled containers.
In order to obtain optimum results using this method, the chemical composition of the item must be well known, the container wall must permit transmission of the 185.7 keV gamma-ray, and the uranium-bearing material within the item must be infinitely thick with respect to the 185.7 keV gamma-ray. All items must be in identical containers or must have a known container wall thickness and composition.
Items to be measured must be homogeneous with respect to both 235U fraction and chemical composition.
When measuring items, using low-resolution detectors, in thin-walled containers that have not reached secular equilibrium (more than about 120 days after processing), either the method should not be used, additional corrections should be made to account for the age of the uranium, or high-resolution measurements should be performed.
The method is often used as a enrichment verification technique.
SCOPE
1.1 This test method covers the quantitative determination of the fraction of 235U in uranium using measurement of the 185.7 keV gamma-ray produced during the decay of 235U.
1.2 This test method is applicable to items containing homogeneous uranium-bearing materials of known chemical composition in which the compound is considered infinitely thick with respect to 185.7 keV gamma-rays.
1.3 This test method can be used for the entire range of 235U fraction as a weight percent, from depleted (0.2 % 235U) to highly enriched (97.5 % 235U).
1.4 Measurement of items that have not reached secular equilibrium between 238U and 234Th may not produce the stated bias when low-resolution detectors are used with the computational method listed in Annex A2.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard may involve hazardous materials, operations, and equipment. 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.

General Information

• Status: Historical
• Publication Date: 30-Jun-2008
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.10 - Non Destructive Assay

Relations

• Replaced By: ASTM C1514-08(2017) - Standard Test Method for Measurement of ²³⁵U Fraction Using Enrichment Meter Principle
• Effective Date: 01-Jan-2017

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1514 − 08
Standard Test Method for
235
Measurement of U Fraction Using Enrichment Meter
1
Principle
This standard is issued under the fixed designation C1514; 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 C1592 Guide for Nondestructive Assay Measurements
C26.10 Terminology Guide
1.1 This test method covers the quantitative determination
235
2.2 ANSI Standard:
of the fraction of U in uranium using measurement of the
235
N42.14 Calibration and Use of Germanium Spectrometers
185.7 keV gamma-ray produced during the decay of U.
for the Measurement of Gamma-Ray Emission Rates of
1.2 This test method is applicable to items containing
3
Radionuclides
homogeneous uranium-bearing materials of known chemical
composition in which the compound is considered infinitely
3. Terminology
thick with respect to 185.7 keV gamma-rays.
3.1 For definitions of terms used in this test method, refer to
235
1.3 Thistestmethodcanbeusedfortheentirerangeof U
Terminology C26.10.
235
fraction as a weight percent, from depleted (0.2 % U) to
235
highly enriched (97.5 % U).
4. Summary of Test Method
1.4 Measurement of items that have not reached secular
4.1 The test method consists of measuring the emission rate
238 234
equilibrium between U and Th may not produce the
of 185.7 keV gamma-rays from an item in a controlled
stated bias when low-resolution detectors are used with the
geometry and correlating that emission rate with the enrich-
computational method listed in Annex A2.
ment of the uranium contained in the item.
1.5 The values stated in SI units are to be regarded as
4.2 Calibration is achieved using reference materials of
standard. No other units of measurement are included in this
known enrichment. Corrections are made for attenuating ma-
standard.
terials present between the uranium-bearing material and the
1.6 This standard may involve hazardous materials,
detector and for chemical compounds different from the
operations, and equipment. This standard does not purport to
calibration reference materials used for calibration.
address all of the safety concerns, if any, associated with its
4.3 The measured items must completely fill the field of
use. It is the responsibility of the user of this standard to
view of the detector, and must contain a uranium-bearing
establish appropriate safety and health practices and deter-
material which is infinitely thick with respect to the 185.7 keV
mine the applicability of regulatory limitations prior to use.
gamma-ray. If the field of view is not filled, a correction factor
must be applied.
2. Referenced Documents
2
2.1 ASTM Standards:
5. Significance and Use
C1030 TestMethodforDeterminationofPlutoniumIsotopic
5.1 The enrichment meter principle provides a nondestruc-
Composition by Gamma-Ray Spectrometry
235
tive measurement of the U fraction of uranium-bearing
C1490 GuidefortheSelection,TrainingandQualificationof
items. Sampling is not required and no waste is generated,
Nondestructive Assay (NDA) Personnel
minimizing exposure to hazardous materials and resulting in
reduced sampling error.
1
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear
5.2 This method relies on a fixed and controlled geometry.
Fuel Cycle and is the direct responsibility of Subcommittee C26.10 on Non
The uranium-bearing materials in the measured items and
Destructive Assay.
calibration reference materials used for calibration must fill the
Current edition approved July 1, 2008. Published August 2008. Originally
approved in 2002. Last previous edition approved in 2002 as C1514 – 02. DOI:
detector field of view.
10.1520/C1514-08.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C1514 − 08
5.3 Use of a low resolution detector (for example, NaI 6.5 Any impurities present in the measured items must be
235
detector) to measure uranium with U fraction approximately homogeneously distributed and well characterized. The pres-
10 % which is contained in a thin-walled container can provide ence of impurities, at concentrations which can measurably
a rapid (typically 100 s), easily portable meas
...

This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately,ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:C1514–02 Designation:C1514–08
Standard Test Method for
235
Measurement of U Fraction using theUsing Enrichment
1
Meter Principle
This standard is issued under the fixed designation C1514; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
235
1.1 This test method covers the quantitative determination of the fraction of U in uranium using measurement of the 185.7
235
keV gamma-ray produced during the decay of U.
1.2 Thistestmethodisapplicabletoitemscontaininghomogeneousuranium-bearingmaterialsofknownchemicalcomposition
in which the compound is considered infinitely thick with respect to 185.7 keV gamma-rays.
235 U fraction as a weight percent, from depleted
1.3 This test method can be used for the entire range of U fraction, from depleted (0.2%
235 235
U) to highly enriched (97.5%
(0.2% U) to very highly enriched (97.5% U).
238 234
1.4 Measurementofitemsthathavenotreachedsecularequilibriumbetween Uand Th,Thmaynotproducethestatedbias
when low-resolution detectors are used with the computational method listed in Appendix B.Annex A2.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard may involve hazardous materials, operations, and equipment. 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.
2. Referenced Documents
2
2.1 ASTM Standards:
C982StandardGuideforSelectingComponentsforEnergy-DispersiveX-RayFluorescence(XRF)Systems 1030 TestMethod
for Determination of Plutonium Isotopic Composition by Gamma-Ray Spectrometry
C1490 Guide for the Selection, Training and Qualification of Nondestructive Assay (NDA) Personnel
C1592 Guide for Nondestructive Assay Measurements
C26.10 Terminology Guide
2.2 ANSI Standard:
N42.14 Calibration and Use of Germanium Spectrometers for the Measurement of Gamma-Ray Emission Rates of
3
Radionuclides
3. Terminology
3.1Infinite thickness—The thickness of a material which is at least seven mean free paths for 185.7 keV gamma rays (i.e., the
minimum thickness which will attenuate 99.9% of 185.7 keV gamma rays incident on the compound).
235
3.2Enrichment—The fraction of U relative to total uranium in an item, typically expressed as a weight percentage.
235
3.3Atom Percent—The ratio of the number of atoms of a given isotope (e.g., U) to the total number of atoms of an element
(e.g., uranium), expressed as a percentage.
235
3.4Weight Percent—The ratio of the weight of a given isotope (e.g., U) to the total weight of an element (e.g., uranium),
expressed as a percentage.
3.1 For definitions of terms used in this test method, refer to Terminology C26.10.
4. Summary of Test Method
4.1 The test method consists of measuring the emission rate of 185.7 keV gamma-rays from an item in a controlled geometry
and correlating that emission rate with the enrichment of the uranium contained in the item.
1
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.10 on Non Destructive
Assay.
Current edition approved Jan. 10, 2002. Published May 2002.
Current edition approved July 1, 2008. Published August 2008. Originally approved in 2002. Last previous edition approved in 2002 as C1514–02.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,[e-mail] Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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C1514–08
4.2 Calibration is achieved using reference materials of known enrichment. Corrections are made for attenuating materials
presentbetweentheuranium-bearingmaterialandthedetectorandforchemicalcompoundsdifferentfromthecalibrationreference
materials used for calibration.
4.3Themeasureditemsmustcomplete
...