Tc metal and metal-like carbide phases are revisited with special attention given to Tc-rich phases in the view of prospective nuclear fuel utilization and alternative transmutation targets fabrication. A new Tc-metal phase has been found and new softer conditions for the Tc carbide formation were observed. The unit cell parameters of a new orthorhombic Tc metal were a = 2.805(4), b = 4.958(8), c = 4.474(5)•ð (V/z = 15.55 •ð) for Tc-C with 1.38 wt.% C and a = 2.815(4), b = 4.963(8), c = 4.482(5) •ð (V/z = 15.65 A) for Tc-C with 1.96 wt.% C.

After fast neutron irradiation, uranium-plutonium nitride U 0.8 Pu 0.2 N is shown to acquire a com plex structure consisting of a solid solution that is based on the nitrides of uranium, plutonium, americium, neptunium, zirconium, yttrium, and lanthanides and contains condensed phases U 2 N 3 , CeRu 2 , BaTe, Ba 3 N 2 , CsI, Sr 3 N 2 , LaSe, metallic molybdenum, technetium, and U(Ru, Rh, Pd) 3 intermetallics. The con tents and compositions of these phases are calculated at a temperature of 900 K and a burn up fraction up to 14% (U + Pu). The change in the composition of the irradiated uranium-plutonium nitride is studied during the electron decay of metallic radionuclides. The kinetics of transformation of U 103 Ru 3 , 137 CsI, 140 Ba 3 N 2 , and 241 PuN is calculated.

No abstract

No abstract

No abstract