Investigation of neutron and photon flux spectra in a streaming mock-up for ITER

A neutronics mock-up of the International Thermonuclear Experimental Reactor (ITER) inboard shielding system with streaming path for the fusion neutrons was investigated in order to validate the design. Neutron and photon flux spectra were measured at several positions in the assembly. The experimentally determined flux spectra are analysed with the ITER design tools Monte Carlo code MCNP-4A and Fusion Evaluated Nuclear Data Library FENDL-1 and FENDL-2. Helium production, radiation damage and photon heating rates, which are design parameters of the shielding system are derived from both, the measured and the calculated spectral fluxes.