Destructive Testing of HFIR Irradiation “Rabbit” Capsules to Establish Containment Safety Limitations

Irradiation capsule containments, commonly referred to as rabbit capsules, are uninstrumented experiment capsules designed to facilitate irradiation of advanced materials, radioisotopes, and fuels in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Rabbit capsules are versatile, as they are able to accommodate various shapes and sizes of specimens, and they can generally reach target temperatures between 200–1200°C. The rabbit capsules’ modes of failure under internal pressurization are important to characterize and understand, particularly when considering how failures can affect HFIR coolant flow channels. Destructive testing was completed on single- and double-ended thin-walled rabbit capsules to establish a mode of failure under internal pressure and to characterize elastic/plastic diametrical deformation. This report details the methods, results, and conclusions of the destructive testing.