Neutronics shield experiment for the fusion reactor design

Shielding neutronics experiments have been performed at the Frascati 14-MeV Neutron Generator (FNG), in the framework of the ITER EDA R&D Programme, to verify the nuclear performance of the shielding blanket of ITER fusion reactor, and to provide validation of nuclear data used in ITER design. The experiment has been performed on a mock-up of the inboard shield blanket, where the critical nuclear loads are predicted. Here, neutron reaction rates, with energy thresholds ranging from 13 MeV down to thermal, have been measured as a function of the penetration depth, up to about 1 m. The analysis with MCNP-code using FENDL-1 and EFF-3 libraries, allowed to conclude that the uncertainty in the calculations due the nuclear data base and numerical code is within +/-15% in the shielding blanket and +/-30% in the toroidal field coil region.