Irradiation - High heat flux synergism in silicon carbide-based fuel claddings for light water reactors

Silicon carbide-based fuel cladding for light water reactors is anticipated to develop a unique stress state as a combined result from the high radial heat flux and irradiation-induced swelling assisted by thermal conductivity decrease. In order to verify the multi-physics analysis of this unique stress state, a novel experiment capturing the synergism of a high radiation field and a high radial heat flux in tubular silicon carbide specimens had been designed and implemented in the High Flux Isotope Reactor, Oak Ridge National Laboratory. In this experiment, small diameter tube test specimens made of monolithic or composite silicon carbide were irradiated to a dose of ∼2x1025 n/m2 (E > 0.1 MeV) under a radial heat flux of ∼0.6 MW/m2 while the outer surface temperature was maintained at a target temperature of ∼300°C achieving a steep temperature gradient through the cladding wall thickness. In this paper, the technical planning and execution of the experiment are discussed.