Efficiency of an electronuclear plant with a fused-salt blanket and a neptunium breeding target

Abstract

One of the difficulties standing in the way of electronuclear transmutation and power plants are the extremely high requirements imposed on the power of the proton accelerator. For example, the power of a proton beam in the electronuclear plant design developed on the basis of the ABC program at the Los Alamos National Laboratory in the USA is equal to 64 MW [1]. This difficulty can be substantially decreased by using specific multisection blankets. As shown in [2], the power of the proton accelerator can be decreased by many times by using in the electronuclear plant a multisection blanket with deep-valve neutron coupling.The blanket displayed in Fig. 1 is being considered as a schematic variant of this suggestion. In this scheme the fissioning material is threshold 237Np in the inner section and 235U in the outer section. Once the neutrons produced in the inner section enter the outer section after being moderated in layer 5 they easily give rise to fissioning in the outer section. Neutrons produced in the outer section and passing through the same moderation phase cannot give rise to fissioning in the inner section. This is what determines the valve nature of the coupling in the scheme displayed in Fig. 1. A multisection blanket can also be considered on the same basis.The neutron characteristics of the scheme, shown in Fig. 1, of a two-section blanket and similar multisection schemes were obtained in [2] on the basis of an analytical solution of the equations for coupled reactors in the form of the equations derived by R. Avery [3]. The parameters of these systems which determine the neutron characteristics are the total subcriticality of the system Ak = 1 -k, the subcriticality of a separate section Ak i = 1 -k i (i = 1, 2), and the neutron-coupling coefficients k12 and k21 (kij is the multiplication factor in the i-th section for neutrons produced in the j-th section).The work [2] stimulated further calculations, but associated with the specific electronuclear plant in the ABC design. The problem addressed in these calculations was formulated by A. Faval (Grumman Aerospace Corporation, USA) and V. F. Kolesov (VNIIt~F, Russia). The concept of a valve-section system is expressed in this problem as a combination of the design blanket based on fused plutonium salt (section 2) and a breeding target made of 237Np metal (section 1). (A two-section system in the form of a combination of a blanket and a breeding target was previously discussed in [4]. It was assumed that the valve coupling in this system is realized as a result of placing a layer of a thermal-neutron absorber on the boundary between the sections.) Calculations of the neutron characteristics of this system with neptunium as well as of a design system with a thorium target were performed. Moreover, to obtain a more complete idea of the role of the readiness factor of the fissioning material in the system with neptunium, some calculations were performed for a system with a design blanket and a target consisting of uranium enriched up to 90% with 235U.T...

Experiments on cascade-reactor models

“…The All-Russia Research Institute of Experimental Physics, the Physics and Power-Engineering Institute, the Institute for Theoretical and Experimental Physics, the Russian Science Center Kurchatov Institute, the All-Russia Research Institute of Technical Physics, the Joint Institute for Nuclear Research (Russia), the Argonne, Los Alamos, and Sandia National Laboratories (USA), and Erevan University (Armenia) have all shown interest in the cascade reactors [1][2][3][4][5][6][7][8][9][10][11][12].…”

“…In the 1980s, great interest was shown in these systems because it was thought that they could substantially decrease the duration of radiation pulses in reactors and boosters and decrease the power of the proton accelerator in electronuclear facilities [1][2][3][4].…”