Neutron Cross Section Evaluation of Tungsten and Tantalum

The evaluations of neutron cross sections and covariances are presented for tungsten and tantalum which are considered as a prime candidate of plasma facing materials in fusion reactors and/or a structural material of the Korea Helium Cooled Ceramic Reflector (Ko HCCR) Test Blanket Module (TBM). The Fusion Evaluated Nuclear Data Library (FENDL-2.1) has been employed as the nuclear data for the neutronics analysis to obtain the optimal design parameters for Ko HCCR TBM. However, the neutron cross sections and energy and/or angular dependent neutron spectra from FENDL-2.1 showed some discrepancies with the differential and integral measured data available for tungsten and tantalum. In response to these situations, the neutron cross section for 181Ta and 180,182,183,184,186W have been newly evaluated using the up-to-date nuclear reaction code and the measured data available.