Development of Efficient Safeguards Destructive Analysis Procedures at NMCC-SAL

The Uranium and Plutonium isotopic compositions and concentrations of safeguards inspection samples are measured mainly by the mass spectrometry and isotopic dilution mass spectrometry (IDMS) at Safeguards Analytical Laboratory of Nuclear Material Control Center (NMCC-SAL) in Japan. In these methods, chemical separation of U, Pu, Am and other interfering nuclides, and precise measurement of isotopic compositions are indispensable. The ion exchange procedure is used for the separation, but it requires a lot of workload and long operation time to result in inefficient analytical procedures. For mass spectrometry, it generally takes about an hour for the measurement of one sample by the conventional method using bias collection factor (BCF). In order to improve the efficiency of analysis, automated ion exchange separation unit was developed to reduce workload, and total evaporation mass spectrometry method was examined to reduce measurement time. These methods are expected to be used at Rokkasyo Reprocessing Plant On Site Laboratory (RRP-OSL) in future. This paper will describe the outline of these analytical procedures with emphasis on the performance of the automated ion exchange unit and total evaporation method, as well as their analytical results compared with conventional methods.