Simulations for practical measurement methods of spatial neutron distribution inside blanket mock-up irradiated with DT neutrons

Abstract

Measuring methods of spatial neutron distribution have been required for the evaluation of TBR inside the blanket. In this paper, neutron transport inside a blanket mock-up, mainly assembled by beryllium neutron multiplying layers and lithium breeding layers, was simulated for measurements of the neutron energy spectrum and the spatial distribution with activation analyses using activation foils and an imaging plate. Transport of deuterium-tritium (DT) fusion reaction neutrons were simulated by MCNP6 and activation calculations were performed by DCHAIN. These results of neutron transport indicate that activation foils were reacted to neutrons with specific energies; dysprosium for thermal, manganese with cadmium for epi-thermal and niobium or cobalt for fast neutrons. The results of activation calculations indicate each activity of activation foils inside the blanket, which proposes the exposure conditions for measurements using imaging plate.