Fabrication and characterization of driver-fuel particles, designed-to-fail fuel particles, and fuel compacts for the US AGR-3/4 irradiation test

Fuel compacts have been fabricated for the third in a series of irradiation tests designed to study tri-structural isotropic (TRISO) coated particle fuel performance in support of advanced gas-cooled reactor (AGR) development. The purpose of this third irradiation test, designated as AGR-3/4, is to measure fission product release and transport by irradiating compacts containing a small fraction of fuel particles that are intentionally designed to fail (DTF) early in the irradiation test. Transport of fission products released by the mixed uranium carbide/uranium oxide kernels within the DTF particles will be studied in the compact's carbon matrix and in cylindrical rings surrounding the compacts, which were made from either compact matrix material or structural graphite. Results will be used to refine fission product transport models. Coating of the 20-μm-thick pyrocarbon-coated DTF and standard TRISO driver-fuel particles, fabrication of the fuel compacts containing these particles, and characterization of the key fuel properties are discussed in this paper.