Neutron transport and benchmark on granular tungsten samples with 14.8 MeV neutrons

The leakage neutron spectrum from granular tungsten samples was measured by a TOF technique at 60°. The neutron transport and benchmark on granular tungsten samples were investigated using MCNP-4C simulations with the ENDF/B-VII.1, CENDL-3.1, JEFF-3.2, JENDL-4.0 and TENDL-2015 evaluated nuclear data libraries. And four different geometry lattices (FCC, BCC, CHPOP and SC) were considered for the granular tungsten target. The simulated results show that the leakage neutron spectrum mainly depends on the filling factor of granular tungsten. The general trend of the experimental leakage neutron spectrum is well reproduced by MCNP simulation with the ENDF/B-VII.1 library within 15% error. However, the inelastic contribution at around En = 10 MeV with CENDL-3.1 library largely underestimates the cross section. The discrepancies of the leakage neutron spectra in the MCNP simulations originate simply from the differences in the spectra distributions of the neutron reaction channels in the evaluated nuclear data libraries.