Rationale

The test method C1832-23 "Determination of Uranium Isotopic Composition by Modified Total Evaporation (MTE) Method Using Thermal Ionization Mass Spectrometer" should be revised in order to include also measurements of test samples, which are HEU samples (highly enriched uranium) with quite low 236U (236U/238U<1E-6). TIMS measurements for these samples require a hydride correction which is quite unusual for TIMS, but already a routine for other mass spectrometry test methods like ICPMS and SIMS.