Neutron shielding calculation for DEMO-Prad/SXR measurement system

In plasma fusion devices, the selection of shielding materials is one of the challenges for plasma diagnostic and control systems under high radiation levels during long operation times. This study presents the effect of shielding materials on neutron flux for a radiated power and soft x-ray core intensity measurement system for a DEMOnstration power plant. A calculation model of neutron shielding was used to investigate the neutron shielding performance of borides and carbides for a large distance from plasma to the diagnostic system. The neutron fluxes were characterized for three points close to the measurement system location. The related neutronic calculations were performed with an ADVANTG hybrid code to obtain neutron flux distribution and attenuation rate depending on the thickness of shielding materials. The results indicate that B4C, W2B5, and WB4 are the most effective options to serve as shielding material due to the effect of boron on neutron shielding effectiveness.