Measuring Isotope Ratios

A new ASTM International test method will help improve the measurements of uranium isotope ratios, helping laboratories analyze nuclear material and supporting efforts of organizations like the International Atomic Energy Agency (IAEA). The new standard ASTM standard C1832 is entitled "Test Method for Determination of Uranium Isotopic Composition by the Modified Total Evaporation (MTE) Method Using a Thermal Ionization Mass Spectrometer."

According to ASTM member Stephan Richter, for the past several years, the MTE method has proven to be a significant improvement for measuring isotope ratios for certification work at the New Brunswick Laboratory (part of the U.S. Department of Energy) and the Institute for Reference Materials and Measurement (part of the Joint Research Center of the European Commission). In addition, the MTE method has been used for nuclear safeguards measurements at the International Atomic Energy Agency and the Institute for Transuranium Elements (ITU), which is also part of the European Commission's JRC. Specifically, the MTE method has significantly helped with measuring the so-called "minor" isotope ratios such as 234U/238U and 236U/238U, because they can provide information about the specific enrichment processes and/or the origin of nuclear material.

"In 2013, organizations like the IRMM and NBL started working through ASTM to develop a standard for the MTE method," says Richter, who works at IRMM. "The collaboration worked very well. This new standard not only provides a more detailed description and instruction for users, it also provides information about the typical analytical performance to be expected." Richter notes that the standard can also be used to evaluate the quality of measurements for the user's own quality system, as well as by accredited organizers of interlaboratory comparisons (round-robin measurements) by organizations such as JRC-IRMM, New Brunswick Laboratory, IAEA and others.

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CONTACT Technical Information: Stephan Richter, Institute for Reference Materials and Measurements • Geel, Belgium • tel +32.14.571.701 | ASTM Staff: Joe Koury • tel +1.610.832.9804 | Upcoming Meeting: June 12-17, 2016 • Vienna, Austria

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