IRRADIATION PERFORMANCE OF HTGR FERTILE FUELnIN HFIR TARGET CAPSULES HT-12 THROUGH HT-15:PART I - EXPERIMENT DESCRIPTION AND FISSION PRODUCT BEHAVIOR

摘要

This report addresses the description of the experiment and extensive postirradiation analyses and experiments to determine fertile-particle burnup, fuel coating failures, and fission product behavior. Several low-temperature isotropic (LTI) pyrocarbon coatings, which "survived" according to visual inspection, were shown to have developed permeability during irradiation. These particles were irradiated at temperatures ≈1250° C and to burnups ≥8% fission per initial heavy-metal atom (FIMA). No evidence of permeability was found in similar particles irradiated at temperatures—1550° C and burnups ——16% FIMA. Failures due to permeability were not detectable by visual inspection but required a more extensive investigation by the 1000°C gaseous chlorine leaching technique.