Instrumented Fast-Reactor Irradiation of Boron Carbide Pellets

Eighteen boron carbide specimens were irradiated for 355 effective full-power days in the Experimental Breeder Reactor II to maximum burnups of 82 x 10²⁰ capture /cm³. Baseline specimens were patterned after Fast Flux Test Facility reference boron carbide, and material variables of ¹⁰B enrichment, pellet density, grain size, and stoichiometry were investigated in the test. Irradiation temperatures ranged from 1175 to 1570°F (635 to 855°C). Each specimen was individually instrumented to measure temperature and helium release continuously during irradiation.Postirradiation examination provided information on pellet integrity, swelling, tritium retention, and compatibility with stainless-steel containment components.