Standard Test Method for Determination of Uranium Isotopic Composition by the Modified Total Evaporation (MTE) Method Using a Thermal Ionization Mass Spectrometer

SIGNIFICANCE AND USE
5.1 Uranium material is used as a fuel in certain types of nuclear reactors. To be suitable for use as nuclear fuel, the starting material shall meet certain specifications such as those described in Specifications C753, C776, C787, C833, C967, C996, and C1008, or as specified by the purchaser. The isotope amount ratios of uranium material can be measured by mass spectrometry following this test method to ensure that they meet the specification.  
5.2 The MTE method can be used for a wide range of sample sizes even in samples containing as low as 50 μg of uranium. If the uranium sample is in the form of uranium hexafluoride, it can be converted into a uranium nitrate solution for measurement by the MTE method. The concentration of the loading solution for MTE has to be in the range of 1 to 6 mg/g to allow a sample loading of 2 to 6 μg of uranium. A minimum loading of 3 μg uranium per filament is recommended. This is needed to have a suitable ion signal especially for the two minor isotopes (234U and 236U) thus enabling the internal calibration of SEM versus the Faraday cups during the measurement.  
5.3 Until now, the instrument capabilities for the MTE method have only been implemented on the TRITON™ TIMS instrument.5 Therefore all recommendations for measurement parameters in this test method are specified for the TRITON™ TIMS instrument. The manufacturers of other TIMS instruments (for example, IsotopX and Nu Instruments) have plans to implement the modifications needed in their instruments to use the MTE method.  
5.4 The MTE method described here can also be extended to measurement of elements other than uranium. Note that the MTE method has already been implemented for plutonium and calcium.
SCOPE
1.1 This test method describes the determination of the isotope amount ratios of uranium material as nitrate solutions by the modified total evaporation (MTE) method using a thermal ionization mass spectrometer (TIMS) instrument.  
1.2 The analytical performance in the determination of the 235U/238U major isotope amount ratio by MTE is similar to the (“classical”) total evaporation (TE) method as described in Test Method C1672. However, in the MTE method, the evaporation process is interrupted on a regular basis to allow measurements and subsequent corrections for background form peak tailing, perform internal calibration of a secondary electron multiplier (SEM) detector versus the Faraday cups, peak centering, and ion source refocusing. Performing these calibrations and corrections on a regular basis during the measurement, improves precision, and significantly reduces uncertainties for the minor isotope amount ratios 234U/238U and 236U/238U as compared to the TE method.  
1.3 In principle, the MTE method yields major isotope amount ratios without the need for mass fractionation correction. However, depending on the measurement conditions, small variations are seen among sample turrets; therefore, a small correction based on measurements of a certified reference material is recommended to improve consistency. The uncertainty around the mass fractionation correction factor usually includes unity.  
1.4 Units—The values stated in SI units are to be regarded as the standard. When non-SI units are provided, they are for information only.  
1.5 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
14-Jan-2016
Technical Committee
Drafting Committee
Current Stage
Ref Project

Buy Standard

Standard
ASTM C1832-16 - Standard Test Method for Determination of Uranium Isotopic Composition by the Modified Total Evaporation (MTE) Method Using a Thermal Ionization Mass Spectrometer
English language
22 pages
sale 15% off
Preview
sale 15% off
Preview

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:C1832 −16
Standard Test Method for
Determination of Uranium Isotopic Composition by the
Modified Total Evaporation (MTE) Method Using a Thermal
1
Ionization Mass Spectrometer
This standard is issued under the fixed designation C1832; 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 2. Referenced Documents
2
1.1 This test method describes the determination of the 2.1 ASTM Standards:
isotope amount ratios of uranium material as nitrate solutions C753Specification for Nuclear-Grade, Sinterable Uranium
by the modified total evaporation (MTE) method using a Dioxide Powder
thermal ionization mass spectrometer (TIMS) instrument. C776Specification for Sintered Uranium Dioxide Pellets
C787Specification for Uranium Hexafluoride for Enrich-
1.2 The analytical performance in the determination of the
235 238 ment
U/ U major isotope amount ratio by MTE is similar to the
C833Specification for Sintered (Uranium-Plutonium) Diox-
(“classical”)totalevaporation(TE)methodasdescribedinTest
ide Pellets
MethodC1672.However,intheMTEmethod,theevaporation
C859Terminology Relating to Nuclear Materials
processisinterruptedonaregularbasistoallowmeasurements
C967Specification for Uranium Ore Concentrate
and subsequent corrections for background form peak tailing,
C996Specification for Uranium Hexafluoride Enriched to
perform internal calibration of a secondary electron multiplier
235
Less Than 5% U
(SEM) detector versus the Faraday cups, peak centering, and
C1008 Specification for Sintered (Uranium-Plutonium)
ion source refocusing. Performing these calibrations and cor-
3
DioxidePellets—Fast Reactor Fuel (Withdrawn 2014)
rections on a regular basis during the measurement, improves
C1068Guide for Qualification of Measurement Methods by
precision, and significantly reduces uncertainties for the minor
234 238 236 238
a Laboratory Within the Nuclear Industry
isotope amount ratios U/ U and U/ U as compared to
C1128Guide for Preparation of Working Reference Materi-
the TE method.
als for Use in Analysis of Nuclear Fuel Cycle Materials
1.3 In principle, the MTE method yields major isotope
C1156Guide for Establishing Calibration for a Measure-
amount ratios without the need for mass fractionation correc-
ment Method Used toAnalyze Nuclear Fuel Cycle Mate-
tion. However, depending on the measurement conditions,
rials
small variations are seen among sample turrets; therefore, a
C1347Practice for Preparation and Dissolution of Uranium
small correction based on measurements of a certified refer-
Materials for Analysis
ence material is recommended to improve consistency. The
C1411Practice for The Ion Exchange Separation of Ura-
uncertainty around the mass fractionation correction factor
nium and Plutonium Prior to Isotopic Analysis
usually includes unity.
C1625Test Method for Uranium and Plutonium Concentra-
1.4 Units—The values stated in SI units are to be regarded tions and Isotopic Abundances by Thermal Ionization
Mass Spectrometry
as the standard. When non-SI units are provided, they are for
information only. C1672Test Method for Determination of Uranium or Pluto-
nium Isotopic Composition or Concentration by the Total
1.5 This standard does not purport to address all of the
Evaporation Method Using a Thermal Ionization Mass
safety concerns, if any, associated with its use. It is the
Spectrometer
responsibility of the user of this standard to establish appro-
D1193Specification for Reagent Water
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Standards volume information, refer to the standard’s Document Summary page on
Test. the ASTM website.
3
Current edition approved Jan. 15, 2016. Published January 2016. DOI: 10.1520/ The last approved version of this historical standard is referenced on
C1832-16. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1832−16
E2655Guide for Reporting Uncertainty of Test Results and 3.3.18 RSD—relative standard deviation—SD (see below)
Use of the Term Measurement Uncertainty inASTM Test divided by the mean value of the observations in repeated
Methods sampling
E2586Practice for Calculating and Using Basic Statistics
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.