LIQUID-METAL COOLANTS FOR NUCLEAR POWER

Abstract

Liquid-metal coolants for nuclear power systems are compared taking account of the general laws and individual physical-chemical properties of liquid metals, for which unique nuclear-physical and thermophysical properties, and low vapor pressure at high temperature are characteristic and the experimental data on the properties of metal melts can be generalized on the basis of thermodynamic similarity theory and the thermophysical parameters of these systems can be determined more accurately. Coolants are ranked under different thermohydraulic conditions: for the same transported power and the same Peclet number, which also fixes the Nusselt and Stanton numbers, for all melts. It is found that for heavy coolants the reactor core should be “open” with flow sections 10 times greater than for alkali metals. The lead velocity should be less than the sodium velocity by the same amount. For lithium, a core which is twice as compact is admissable, and the lithium velocity should be one-third that of sodium. The understanding of the microstructure and atomic dynamics of metal melts, physical-chemical processes occuring in such melts, and experience in handling such melts make it possible to adjust their characteristics so as to achieve prescribed performance indicators by using specific additives.