Postirradiation examination report of TRISO and BISO coated ThO/sub 2/ particles irradiated in capsules HT-31 and HT-33. [HTGR]

Capsules HT-31 and HT-33 were uninstrumented capsule experiments irradiated in the target position of the High-Flux Isotope Reactor at Oak Ridge National Laboratory. The experiments were used to evaluate the irradiation performance of (1) fuel fabricated in a 240-mm-diameter coater for production scale-up, (2) TRISO ThO/sub 2/ and BISO ThO/sub 2/ particles, and (3) fuel with certain OPyC variables. A total of 16 BISO particle samples and 32 TRISO particle samples were irradiated to fast neutron fluences ranging from 4.0 to 11.7 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGR/ and heavy metal burnups between 3.5% and 13.2% FIMA at temperatures from 1150/sup 0/ to 1530/sup 0/C