Speaker
Description
Recent progress in high temperature superconducting (HTS) magnets has greatly enhanced the potential of spherical tokamaks (ST) for harnessing fusion energy. Given the compactness of an ST and high plasma density, the centre column shield is subjected to challenges such as high neutron load, volumetric heating from neutrons and gamma radiation, and a limited amount of available space. The selected material must exhibit exceptional neutron and gamma attenuation for ensuring magnet lifetime, good thermo-mechanical properties for heat removal, with minimal radioactive waste.
A combination of python scripts and Monte Carlo radiation transport codes have been utilised to select optimal materials based on their shielding properties for different neutron and photon energy ranges. For STs, a combination of Tungsten Borides or Carbides are used to shield high energy neutrons. Once the materials were selected, a combination of high-fidelity unstructured mesh neutronics calculations and FEA analyses are used to assess conceptual shield designs for shielding efficacy as well as heat management of the shield.
