NEUTRON AND PHOTON FLUX SPECTRA IN A MOCK-UP OF THE ITER SHIELDING SYSTEM

A neutronics mock-up of the ITER inboard shielding system including fi rst wall, shield-blanket, vacuum vessel and magnetic field coils, was investigated in order to validate calculational tools used for the ITE R design and to verify the nuclear performance of the shield by measur ing neutron and photon flux spectra at two positions inside the bulk a ssembly. The measured spectra are compared with results from calculati ons using the Monte Carlo code MCNP-4A and the data library FENDL-1. I ntegral values such as neutron-induced reaction rates and gamma-heatin g are calculated on the basis of the experimentally obtained flux spec tra, and are compared with independent measurements of these data. Hel ium and hydrogen production rates, as well as the radiation damage rat e, are determined again by using the measured flux spectra. (C) 1998 E lsevier Science S.A. All rights reserved.