Features of Radiation Swelling of Uranium-Plutonium Nitride Fuel in Experimental Fuel Rods with Helium and Lead Sublayer

Experimental fuel rods with mixed uranium-plutonium nitride fuel are being tested in the BOR-60 reactor as part of collapsible irradiation devices, which are prototypes of fuel rods of the BREST-OD-300 reactor being designed. Currently, reactor tests of fuel rods with a helium sublayer as part of OU-2, as well as lead alloyed with components of EP823-Sh steel as part of OU-4, are continuing. In 2018, one fuel rod was removed from OU-2 and one OU-4 after the first stage of reactor tests with the rods replaced by others from those previously irradiated and post-reactor studies were performed. Information on the features of the radiation swelling of the uranium-plutonium nitride fuel of these fuel rods is presented.