Author(s)

P. N. Alekseev, A. L. Shimkevich, I. Yu. Shimkevich

Abstract

The liquid-metal microstructure is a correct subdivision of Delaunay simplexes (triangular pyramids with atoms in their vertexes). Its dense part consists of almost regular tetrahedrons connected by faces in ramified clusters. Any metal additive (as a second component of alloy) can be outside of these tetrahedral clusters or into them as a constituent of dense liquid part. These structural states of liquid alloy convert to each other at its eutectic composition. Such the polymorphic conversion of the liquid-metal alloy is approved by molecular-dynamics simulating the Pb–K alloy and can be applied to any eutectic, for example, Na_0.93Tl_0.07 with the melting point of 64°C. At the sodium side of this point, a homogeneous solution of thallium is formed in liquid sodium which becomes the colloidal one with clusters, (Na₆Tl)_n, when it is passing the eutectic point. Such the modified sodium coolant enriched by the isotope, ²⁰⁵Tl, can appear attractive for inhibiting the chemical activity of this coolant maintained by oxygen-free technology. An alternative liquid-metal coolant for fast nuclear reactors is eutectic, Pb_0.83Mg_0.17, with the melting point of 248°C. This liquid alloy as a modified lead coolant maintained by the same oxygen-free technology can appear attractive for inhibiting the high corrosion activity of molten lead.

Keywords

liquid-metal eutectics, density fluctuations and tetrahedral clusters, sodium or lead solvent, thallium or magnum additive