부산대학교 도서관

A simulation package has been developed to holistically identify and assess unique signatures for nuclear material and nuclear processing verification. Specifically, this simulation effort is used to predict material response and identify nuclear signatures unique to industrial processing. A systematic approach has been developed for analyzing nuclear resonance structures within the epithermal energy range of the mechanical neutron time-of-flight (TOF) system that has been proposed for the Pennsylvania State Breazeale Reactor (PSBR). This comprehensive data analysis approach is based on identifying and optimizing a library of composition data for hypothetical nuclear samples (such as uranium minerals, ore concentrates, and industrial process waste material) based on existing results of inductively coupled plasma mass spectrometry (ICP-MS) experiments from literature and ASTM standards. These data are used to determine the macroscopic cross-sections of all isotopes in all theoretical samples. In addition, a series of verification tests are being developed to determine the level of element/isotope uniqueness amongst the theoretical samples. These tests include the presence or absence of elements and isotopes in the samples, the presence or absence of combinations of elements and isotopes in the samples, resonance peak ratio tests normalized to a comparator isotope, and the number of rare earth elements that can be observed in the samples. This data analysis methodology, along with the development of a data library, will allow for the identification of the most unique signatures for given nuclear material definitions with reference to ICP-MS. These signatures can then be used to make inferences on sample provenance or industrial processing from time-correlated prompt gamma activation analysis by being selectively sensitive to isotopic composition, while reducing the "noise" signal through reduced thermal activation and gated-detection of prompt gammas. Finally, this data analysis methodology will also be used to compare thermal- and epithermal-neutron sensitivities to assess performance of the PSBR neutron chopper system.