| Abstract Scope |
Understanding fission-product retention and release from fuel under both normal and off-normal conditions is essential for reactor safety analyses. This is especially critical for tristructural isotropic (TRISO)-coated particle fuel used in high temperature gas-cooled reactors (HTGRs), where the fuel itself serves as the primary barrier to fission-product release (a design doctrine referred to as “functional containment”). For key radionuclides, this presentation will summarize fission product release both in-pile and during post-irradiation safety testing from the Advanced Gas Reactor (AGR) Fuel Development and Qualification Program.
The release data come from post-irradiation examination (PIE) of the four AGR irradiation experiments, i.e., AGR-1, AGR-2, AGR-3/4, and AGR-5/6/7. The current PIE of AGR-5/6/7 is ongoing, but some preliminary results will be discussed. The study of in-pile release of condensable fission products involves analyzing fuel compacts and irradiation capsule components for fission-product inventories after the irradiation has been completed. High-temperature safety tests assess the fuel’s ability to retain fission products and determine the rates of fuel particle failure in hypothetical depressurized conduction cool-down events.
Additionally, the frequencies of silicon carbide (SiC) failure and TRISO-coating failure from irradiation and post-irradiation safety testing will be discussed. |