Shutdown dose rate mitigation in the ITER upper ports

In this work, the D1SUNED code has been used to characterize the shutdown dose rate (SDDR) in the ITER Upper Port (UP) interspace due to activation induced by two neutron sources: plasma prompt neutrons and N-17 decay neutrons emitted from the activated cooling water conducted through the UP. Furthermore, shielding measures have been proposed to mitigate the SDDR in the UP interspace; a set of conceptual shields has been designed and inserted into the MCNP computational model C-lite v2 covering the Vacuum Vessel UP Stub Extension and the UP Connecting Duct. The results have shown that the integration of proposed shields has significantly decreased the SDDR due to the activation induced by plasma prompt neutrons, while the activation induced by N-17 decay neutron has a negligible contribution to the total SDDR in the ITER UP interspace.