Effect of the p Decay of Metallic Fission Products on the Chemical and Phase Compositions of the Uranium-Plutonium Nitride Nuclear Fuel Irradiated by Fast Neutrons

摘要

Thermodynamic analysis of the chemical and phase compositions of uranium-plutonium nitride (U_(0.8)Pu_(0.2))N_(0.995) irradiated by fast neutrons to a burn-up fraction of 14% shows that a structure, which consists of a solid solution based on uranium and plutonium nitrides and containing some elements (americium, neptunium, zirconium, yttrium, lanthanides), individual condensed phases (U_2N_3, CeRu_2, Ba_3N_2, Csl, Sr_3N_2, LaSe), metallic molybdenum and technetium, and U(Ru, Rh, Pd)_3 intermetallics, forms due to the accumulation of metallic fission products. The contents and compositions of these phases are calculated. The change in the chemical and phase compositions of the irradiated uranium-plutonium nitride during the [3 decay of metallic radioactive fission products is studied. The kinetics of the transformations of ~(95)Nb_(41)N, ~(143)Pr_(59)N, ~(151)Sm_(62)N, and ~(147)NdN into ~(95)Mo_(42) + N_(s.s.), ~(143)Nd_(602)N, ~(151) Eu_(63)N, and ~(147)SmN, respectively, is calculated.