Treffer: Soliton-like waves of nuclear burning in the neutron multiplicating media : (theory and computational approach)

Byegunova O. Soliton-like waves of nuclear burning in the neutron multiplicating media : (theory and computational approach) . Bielefeld (Germany): Bielefeld University; 2009. ; The research project has dealt with a conceptual design of a model of an innovative inherently safe nuclear soliton-like fast reactor of Feoktistov type. The main findings are summarized below. The kinetics of self-stabilising fast uranium-plutonium reactor, which generates self-propagating neutron-fission nuclear burning wave, that satisfies all conditions of inherent safety, was considered for the Feoktistov uranium-plutonium fuel cycle. For simplicity the neutron spectrum was assumed the same as the fission spectrum. A case with little or no moderator was considered - the neutron spectrum is the same as the initial neutron spectrum. The auto-wave solution for the transmutation chain with necessary condition n_crit < ñ_Pu was obtained and analyzing this solution it was shown that the soliton-like propagation of neutron-fission nuclear burning wave is possible in U_238 medium only under the condition of a certain ratio between equilibrium and critical plutonium concentration (ñ_Pu > n_crit), which is characterized by Bohr-Sommerfeld quantization condition. A preliminary model of nuclear fast reactor of Feoktistov type is proposed. The obtained model satisfied the requirement of inherent safety. The numerical experiments of nuclear reactor with uranium-plutonium fuel cycle are made and the solution in the form of soliton-like progressive burning wave is obtained. The physical conditions of Feoktistov wave mode are generalized and the necessary and sufficient condition of the soliton-like wave origin and propagation are first obtained. The soliton-like wave propagation velocity in the neutron-multiplicating medium is generally defined by two conditions, one of them the necessary one is predetermined by ratio of equilibrium plutonium concentration and critical plutonium concentration n_Pu /n_crit > 1, or, to be more precise, ...