Neutronics in support of the Bioshield Plug design of equatorial port 12 for ITER

In ITER the Bioshield Plug (BP) connects the region inside the cryostat with the Port Cell (PC), which is the first part of the building just behind the bioshield. Therefore, its design has a large impact on the radiation environment of the PC in which worker access for maintenance operations is expected. In this article, dose rates, with a limit for worker access of 10 μSv/h, at 1 day after shutdown are analyzed for four concretes as candidate materials for the BP: (i) the standard used in B-lite (that was the reference input for ITER neutronics), (ii) one with iron added to estimate the impact of a possible iron structure inside the concrete, (iii) other with barite due to its photon shielding capability and (iv) a concrete specifically designed for neutron shielding with high content in H and B. For dose rates calculations R2SUNED system, based on R2S method with mesh approach, was used.