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SiC‐Fission Product Reactions in HTGR TRISO UC 2 and UC x Q y Fissile Fuel: II, Reactions Under Isothermal Conditions
Author(s) -
SMITH C. L.
Publication year - 1979
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1979.tb12742.x
Subject(s) - nuclear fission product , fission products , materials science , fissile material , isothermal process , nuclear engineering , fuel element failure , nuclear fuel , radiochemistry , nuclear reactor , metallurgy , nuclear physics , chemistry , neutron , thermodynamics , physics , engineering
The performance of irradiated TRISO UC 2 and TRISO UC 4.3 0 1.3 HTGR fissile fuel particles was studied by postirradiation isothermal heating at 1600° to 2000°C to evaluate HTGR fuel performance models. Test conditions were similar to reactor conditions predicted for hypothetical core heatup events evaluated during safety and licensing studies. Less than 2% of the particles experienced failure of all coating layers with rapid gaseous and metallic fission product release (pressure vessel failure). Lanthanide fission product, Cs‐137, and Kr‐85 release occurred in the remaining particles by diffusion through intact outer pyrocarbon layers after SiC‐lanthanide fission product reactions had penetrated the SiC layers. The rates of SiC‐fission product reactions depended on the fission density of the test samples and were less than or equal to those observed in a thermal gradient. Test results showed the HTGR fuel performance models to be very conservative.