LMFBR Operational and Experimental In-Core, Local-Fault Experience, Primarily With Oxide Fuel Elements

Abstract

Case-by-case reviews of selective world experience with severe local faults, particularly fuel failure and fuel degradation, are reviewed for two sodium-cooled thermal reactors, several LMFBRs, and LMFBR-fuels experiments. The review summarizes fuel-failure frequency and illustrates the results of the most damaging LMFBR local-fault experiences of the last twenty years, beginning with BR-5, and including DFR, BOR-60, BR2’s MFBS-and Mol-loops experiments, Fermi, KNK, Rapsodie, EBR-II, and Treat-D2. Local-fault accommodation is demonstrated and a need to more thoroughly investigate delayed-neutron and gaseous-fission-product signals is highlighted in view of uranate formation, observed blockages, and slow fuel-element failure-propagation.