Characterization Technique of TRISO Coating of Fuel Particle

Characterization technique of coating layer on brittle multi-coating layer which is able to apply the coating layer of TRISO nuclear particle for HTGR was developed. We proposed a method using tri-layer on the basis of the developed characterization technique of coating layer using bi-layer. In case of indentation on the surface coating layer in flat tri-layer, radial crack occurs by concentration of tensile stress on the bottom part of middle coating layer. Fracture strength was evaluated by measurement of critical load for the crack beginning, and this result was verified by experiments. Indentation was conducted on flat tri-layer(graphite / SiC / Polycarbonate), the fracture strength of SiC coating layer for TRISO nuclear fuel particle was evaluated using suggested strength equation. Critical load for crack initiation was calculated by finite element analysis on curved tri-layer which has various curvature. Difference of critical loads for crack initiation as the thickness and the curvature of coating layer was confirmed. And it was confirmed that these results have same tendencies with indentation experiments on curved tri-layer