Development of Analytical Methodologies in Response to Recent Challenges

At the threshold of the 21st century, new analytical challenges arise in the context of nonproliferation of nuclear material. Development work at the Institute for Transuranium Elements extends to alternative nuclear material, environmental sampling or high performance trace analysis (HPTA), nuclear forensic science and related areas. In the context of alternative nuclear materials, a method for the determination of Np in spent fuel solution was developed, based on chromatographic separation of U, Np, Pu and fission products using a single UTEVA column, followed by alpha spectrometric measurement of 237Np. For forensic analysis and for HPTA, a methodology for the age determination of Pu samples using the isotope pairs 238Pu/234U, 239Pu/235U, 240Pu/236U was developed and implemented. Measurements were carried out by isotope dilution thermal ionisation mass spectrometry and by secondary ion mass spectrometry. The effect of uranium impurities on the accuracy of Pu age determination was investigated for reactor grade and for weapons grade Pu.