Experimental investigation on the release of actinide and cesium from irradiated particles of spherical fuel element of high temperature reactor

The transport behaviour of actinides and cesium in irradiated particles such as BISO and TRISO, good and with failures, of the spherical fuel elements proposed to high temperature reactor is examined experimentally. The experimental procedures are presented and the computer code necessary are discussed. The diffusion coefficients of actinides-plutonium, americium and curium - as well as the cesium fission products are derived from the experimental data with the help of a numerical statistical treatment based on a single diffusion model in multizone spherical geometry. They are presented in the Arrhenius diagram form D=Doe sup(-Q/RT) for the U(Th)-O2 core and for the coating layers HTI-PyC and SiC of the particle. (E.G.)