Basic Study on Remote Analysis for Low-decontaminated TRU Fuel by Combination of Laser Induced Breakdown Spectroscopy (LIBS) and Ablation Initiated Resonance Absorption Spectroscopy (AIRAS)

Basic study on remote analysis by combination of LIBS and AIRAS is performed to apply for a rapid and on-site analysis of low-decontaminated TRU fuel. In this paper, the summary of the study and recent results are presented. For the impurity measurement, by the use of the sample with the matrix of Lanthanide or Uranium oxide, which has complex atomic or ionic spectrum, detection linearity to % order and the sensitivity of order 100ppm were obtained by the optimization of the measurement conditions such as observation delay and gas pressure, and by the spectrum analysis based on the deconvolution technique. For the isotope analysis, the laser system specialized for the resonance spectroscopy by frequency stabilized semiconductor tunable laser, had been developed, and was applied to the resonance absorption spectroscopy for the ablated uranium oxide. Under the low pressure rare gas condition, spectrum resolution of 800MHz, which is narrow enough to separately observe the isotopes, was obtained and 235U in natural uranium was clearly detected. These results suggest that the combination of LIBS and AIRAS will be one of the alternative techniques applicable for the safeguards analysis of next generation fuels without neutron detection by 3He gas.