An aluminum capsule for long-term irradiations in the Hydraulic Capsule Facility (HCF) at the National Reactor Universal (NRU) at Chalk River. The capsule, which would contain the sample to be irradiated, is sealed by cold-welding a flat aluminum disk to it before irradiation. When completed, it measured approximately 70 mm in length, with a maximum outer diameter of approximately 35 mm. A wide variety of materials were irradiated in similar capsules for extended periods during NRU’s lifetime. The neutron flux available at NRU was typically 2.4 x 1014 neutrons/ cm2.
Between 2010 and NRU’s permanent shutdown in 2018, materials of commercial interest were irradiated in the HCF at NRU to confirm calculations and establish techniques for irradiations at Ontario Hydro facilities such as the Darlington Generating Station. These included the irradiation of microspheres of neptunium oxide for the production of Pu238 – an isotope highly valued in the space industry for use in Radioisotope Thermoelectric Generators (RTG) used in deep space probes.
