Analysis of the direct channel for formation of uranium isotopes in the reactions 238U(n, xn)

It was shown previously that one of the important differences in the methods of production of secondary nuclear fuel in the blankets of hybrid thermonuclear reactors and in the breeding zone of fast reactors is the sharp increase in the contamination of the secondary nuclear fuel by 236Pu, 238Pu and 232U, nuclides, whose yield is different because of the different neutron spectra in these setups and the threshold nature of the reactions (n, 2n) and (n, 3n), determining the formation of these nuclides together with the accumulation of secondary nuclear fuel. For neutron energies > 10-20 MeV the probability of nuclear processes accompanied by the emission several particles of the type (n, xn) (n, axn), (n, p), etc. increases significantly. In this work we study reactions with multiple emission of particles caused by the interaction of 1-70 MeV neutrons with 238U nuclei. They encompass the main channels for the formation of uranium isotopes and reflect to a large extent the specific features of the processes occurring at E = 10-70 MeV. Analysis showed that when 238U is irradiated by neutrons of this energy the possibilities for the accumulation of nuclides with A < 238, in particular 232U, increase significantly