Nuclear Material Safeguards Surveillance and Accountancy by Isotope Correlation Techniques

The purpose of this study is to investigate the applicability of isotope correlation techniques (ICT) to the Liquid Metal Fast Breeder Reactor (LMFBR) fuel cycles for nuclear material accountancy and safeguards surveillance. The ICT allows a level of verification of the fabricator's fuel content specifications, the irradiation history, the fuel and blanket assemblies management and scheduling within the reactor, and the subsequent spent fuel assembly flows to the reprocessing plant. The investigation indicates that there exist relationships between isotopic concentrations which have predictable, functional behavior over a range of burnup. Several cross-correlations serve to establish the initial core assembly-averaged compositions. The selection of the more effective functional relationships will depend not only on the level of reliability of ICT for verification, but also on the capability, accuracy and difficulty of developing measurement methods. The propagation of measurement errors on the correlation functions and respective sensitivities to isotopic compositional changes have been examined and found to be consistent with current measurement methods.