Simulation of ion flux of actinides and uranium fission products in the plasma separator with a potential well

Abstract

This work is devoted to the development of a plasma mass separation method with a potential well for spent nuclear fuel reprocessing. The configuration of the separation chamber with an axial magnetic field up to 0.25 T and a radial electric field up to 3 kV/m is considered. Using numerical simulation, we study the ion flux motion with the same mass composition as the spent nuclear fuel injected along magnetic field lines. The effect of fields and initial injection parameters on the spatial separation of actinides from uranium fission products is investigated. The simulation of the ion flux motion is also performed taking into account elastic collisions of ions with background gas atoms. Elastic collision cross sections for U+, Pu+, Cs+, and Sr+ ions in helium and argon are obtained theoretically. We show that in argon, the separation is possible up to a pressure of the order of 1 mTorr, while in helium, it is possible to separate elements by mass groups in the collisional regime at pressures up to about 10 mTorr.

Influence of magnetic field induction on the energy of ions and injection processes of ionized flows of working substances in a plasma mass separator

“…The characteristic time scale of separation at a value of a radial electric field of 15 V/cm and a magnetic field induction of 1400 G for Pb is 44 µs (the time of flight to the substrate for Ag is 30 µs), which, taking into account the geometric factors of the setup, will make it possible to carry out separation with particles up to an energy of 100 eV. It should be noted that plasma separation with a potential well and injection of working substances along magnetic field lines is possible at different values of the radial electric and axial magnetic fields [6]. This leads to the relevance of the study of energy distributions at relatively low values of magnetic induction (up to 150 G).…”

“…One of the primary factors that influences the efficiency of the concept is the initial dynamic characteristics of the particles. Thus, the energy distribution of the separated elements and the direction of injection significantly affect the scale of separation [6,7]. When the flow is injected across the magnetic field lines, the energy distribution of charged particles directly affects the separation efficiency.…”

The Optimal Axis-Symmetrical Plasma Potential Distribution for Plasma Mass Separation

“…The overlap occurs because of an increase in the dispersion (cross-section) of the beams in the components of the mixture. The possible factors leading to this are the scattering of particles by initial velocities and energies, distortions of the potential profile as a result of the injection, as well as fluctuations in the plasma potential [ 19 , 39 ]. Such a source of significant potential fluctuations in the Penning discharge could be a rotating structure, the characteristics of which have been described in Reference [ 40 ].…”

“…Numerical calculations of particle trajectories were carried out in linear and piecewise linear (consisting of two linear sections) axially symmetric potentials in the study [ 39 ]. It was shown that, with a constant radial electric field and the injection of particles at a distance of 25 cm from the axis, the characteristic separation scale was 10 cm.…”

Radial distribution of the plasma potential in a cylindrical plasma column with a longitudinal magnetic field

“…In such separators, the possibility to control the radial profile of the potential is actually the possibility to control the particle trajectories (Smirnov et al. 2018, 2020). Therefore, the question about the shape of the profile and the possibility of its adjustment for more efficient separation of the mixture has become particularly topical.…”