Simulation of Fission Product Release from Microfuel Particles Taking into Account the Effects of Trapped Fraction and Concentration Jumps at the Interfaces

A modification of the FP Kinetics code 1] has been performed to calculate the fission product release from HTGR microfuel particles, allowing for chemical binding, limited solubility effects, and component concentration jumps at the interfaces of the coating layers. A comparison is made of the release curves of Cs from microfuel particles calculated using the FP Kinetics and PARFUME codes 2]. It is shown that taking into account the concentration jumps at the interfaces of the silicon carbide layer makes it possible to give a noncontradictory explanation of the experimental data obtained for Cs release in post-reactor thermal testing. The need for performing experiments to determine the limits of solubility in coating materials is noted.