Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
In molten salt reactors, a nickel-based alloy (NA) named GH3535 is used as structural material such as the vessel, claddings of control rods and the support material of the reactor core. The thermal neutron scattering (TNS) effect of the GH3535 alloy should be considered in the design of the reactor neutronics due to the safety requirements of the Generation IV advanced nuclear power systems. However, there is no TNS data for the NA in the major evaluated nuclear data files (ENDF). Considering the neutron scattering mechanism of the NA is complicated owing to the long-range disordered lattice structure, this study is focused on the lattice structure approximation of the NA in the calculation of TNS data and the data process of the TNS cross section of nickel-based materials. To investigate the lattice structure of the NA, the neutron total cross section (TCS) of the GH3535 alloy is measured using the transmission method based on the TMSR-PNS in this study. An approximation to simplify the lattice structure of the alloy in the calculation of the coherent elastic scattering cross section is proposed according to the conformance of the Bragg edges (BEs) shown in the TCS results between the NA and natural nickel. Meanwhile, the characteristics of the TNS data for nickelbased materials are investigated by generating TNS cross section for natural nickel. To validate the TNS data calculated, the theoretical TCS of natural nickel, which is obtained by combining the calculated scattering cross section in this work and the absorption cross section from the ENDF/B-V library, is compared with experiment results. Fine agreement between the theoretical TCS for natural nickel and experiment results has been achieved.
