Designation: C1344 - 97 (Reapproved 2013) INTERNATIONAL Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Single- Standard Gas Source Mass Spectrometer Method This standard is issued under the fixed designation C1344; the number immediately following the designation indicates the year of superscript epsilon (e) indicates an editorial change since the last revision or reapproval. 1. Scope 2.2 Other Document: USEC-651, Uranium Hexafluoride: A Manual of Good 1.1 This test method covers the isotopic analysis of uranium Handling Practices3 hexafluoride (UFo) and may be used for the entire range of 3. Terminology 1.2 This test method is applicable to the determination of 3.1 Definitions of Terms Specific to This Standard: the isotopic relationship between two UF6 samples. If the 3.1.1 drop through, n-a measurement of the amount of the abundance of a specific isotope of one sample (the standard) is known, its abundance in the other can be determined. This test collector slit and measured on the 235UF,+ collector, stated as method is flexible in that the number of times a given material a percentage of the total 238UF,+ signal. is admitted to the ion source may be adjusted to the minimum 3.1.2 memory corrections, n-corrections applied to the required for a specified precision level. sample analysis results for memory effects. 1.3 The sensitivity with which differences between two 3.1.3 memory effect, n-the inability of the mass spectrom- materials can be detected depends on the measuring system used, but ratio-measuring devices can generally read ratio-of- eter to omit completely the isotopic composition of the sample analyzed previously from attributing to the results of further mol ratio differences as small as 0.0001. samples analyzed. 1.4 The values stated in SI units are to be regarded as 3.1.4 normal isotopic abundance material, n-UF having a standard. No other units of measurement are included in this value of 0.711 weight percent (wt %) 235U. standard. 3.1.5 ratio-of-mol-ratios, n-the mol ratio (235/238U) of 1.5 This standard does not purport to address all of the the sample divided by the mol ratio of the standard, or the safety concerns, if any, associated with its use. It is the inverse condition of the mol ratio of the standard divided by the responsibility of the user of this standard to establish appro- mol ratio of the sample. priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. Specific hazards 4. Summary of Test Method statements are given in Section 7. 4.1 Test Method-The unknown sample and a standard with 2. Referenced Documents an isotopic composition close to that of the sample are introduced in sequence into the Neir mass spectrometer. UFs+ 2.1 ASTM Standards:2 ions of the isotopes are focused through a mass-resolving C787 Specification for Uranium Hexafluoride for Enrich- collector slit and onto a faraday cup collector. Measurements ment are made of 235UF,+ to the total of the other UFs+ isotopes. C996 Specification for Uranium Hexafluoride Enriched to With the known composition of the standard, calculation of the Less Than 5 % 235U 235 U composition of the sample can be determined. 5. Significance and Use This test method is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of 5.1 Uranium hexafluoride is a basic material used to prepare Test nuclear reactor fuel. To be suitable for this purpose, the Current edition approved July 1, 2013. Published July 2013. Originally approved in 1997. Last previous edition approved in 2008 as C1344-97 (2008)el: DOI: material must meet the criteria for isotopic composition. This 10.1520/C1344-97R13. For referenced ASTM standards, visit the ASTM website, www.astm.org, or contactASTMCustome Service at [email protected]. For Annual Book of ASTM Standards volume information, refer to the standard's Document Summary pag