Description
Compact spherical fusion tokamaks require robust neutron shielding to protect superconducting cores from radiation-induced degradation within tight spatial constraints (~50 cm). Tungsten carbide (WC) is a prime candidate shielding material due to its excellent neutron and gamma attenuation properties, but its response to neutron irradiation is not fully understood. This study examined WC's irradiation-induced lattice swelling, defect evolution, and thermal transport degradation using tungsten ion irradiation (0.13–13 dpa; 100–400 °C). Grazing Incidence X-ray Diffraction showed significant initial lattice expansion (1.3% at 0.13 dpa, 100 °C), decreasing with higher temperatures and doses, ultimately transitioning to lattice contraction at high dose (13 dpa). Transmission Electron Microscopy and FIB-SEM revealed pronounced grain boundary cracking in coarse-grained WC and enhanced resistance in fine-grained WC due to refined microstructure. Preliminary Transient Grating Spectroscopy results demonstrated a dramatic reduction in thermal diffusivity (order-of-magnitude drop at lowest dose), highlighting substantial microstructural damage. This work informs WC shielding optimisation and future irradiation studies for advanced tokamak designs.
| Technical Track | Fusion and Advanced Reactors |
|---|
