Nuclear responses in the ITER IVVS port cell

Highlights: • Relevant nuclear quantities in the Port Cells (PC) hosting the IVVS have been calculated by means of the MCNP Monte Carlo. • The neutron and gamma sources needed to perform the nuclear analyses include both the contribution from the radiation streaming through the Lower Port and by activated water. • Absorbed dose on sensitive components over the ITER lifetime has been calculated in the PC area, including contribution from activated water. • Shut down dose rate after 1 day has been calculated in the PC. - Abstract: The ITER In-Vessel Viewing System (IVVS) consists of six identical units located at the B1 level of the Tokamak complex. In this work relevant nuclear quantities in the Port Cell (PC) have been calculated by means of the MCNP Monte Carlo code in a full 3-D geometry, including the IVVS and its shielding blocks. A comprehensive MCNP model of the PC has been developed including a detailed description of the Bioshield plug, pipes, penetrations, cask rails and PC door. The neutron and gamma sources needed to perform the nuclear analyses include both contributions from the radiation streaming through the Lower Port and activated water. Monte Carlo calculations have been performed to assess the radiation field inside the PC through maps of neutron and gamma fluxes. Absorbed dose on sensitive components over the ITER lifetime has been calculated in the PC area, in order to estimate the nuclear loads that the installed equipment has to withstand. Moreover, the shutdown dose rate distribution at 1 day after shutdown has been calculated.