EXPERIMENTAL INVESTIGATION OF NEUTRON AND PHOTON PENETRATION AND STREAMING THROUGH IRON ASSEMBLIES

Nuclear shield parameters of fusion reactors such as ITER are determin ed by the neutron and photon fluxes within and behind the shield. Iron is the main element of shields. In order to verify calculational tool s for the blanket design a solid Fe slab of dimensions 100 cm x 100 cm x 30 cm in thickness was irradiated with 14 MeV neutrons, and the neu tron and photon fluxes penetrating the assembly were measured in wide energy ranges. They are compared with calculated fluxes using the thre e-dimensional Monte Carlo code MCNP and nuclear data of the European F usion File EFF-1. The calculation underestimates the neutron flux at l ow and at high energies. It is discussed in connection with the undere stimated photon flux. The investigation was extended to Fe assemblies with a gap at several positions.