Thermophysical properties of solid and liquid thorium

Abstract

Experimental investigations of the thermophysical properties of both solid and liquid thorium have been made using our isobaric expansion facility. We have performed measurements under 0.06 GPa argon pressure up to the vicinity of the thorium boiling state (~ 5000 K). Enthalpy, volume expansion, and electrical resistivity data are reported and discussed. The electrical resistivity data display the different phase transformations in the solid and liquid states, before showing a sharp rise indicating crossing of the spinodal line. The enthalpies of transformations are measured and are in very good agreement with the available data in literature. Volume measurements show a strong expansion of liquid thorium up to the boiling state (V/Vo~ 2 at 0.68 MJ. kg-t).

Analysis of dislocation mechanism for melting of elements: Pressure dependence

“…( 17),( 20)), we do not consider such cases here, among which there are Pu and Ce. It has been established [24] that for Th, which is in the same column as Ce, △V > 0, and therefore, in view of Eq. ( 23), its melting temperature increases with pressure.…”

Ab initio inspection of thermophysical experiments for zirconium near melting

“…This requires the use of fast pyrometers and the knowledge of normal spectral emissivity as a function of temperature. Over the last decades temperature measurements on pulse heated liquid metal samples [7][8][9][10][11] have always been performed under the assumption that emissivity is constant over the investigated temperature range of the liquid phase and its value equal to that at the melting point, due to the lack of data on the emissivity of liquid metals. This, in turn, can cause large deviations, especially at elevated temperatures, and leads to significant uncertainty in temperature dependent thermophysical properties.…”