Application of the modified mixing rule components and of their data for calculation of thermophysical properties of lead‒potassium alloys

Alloys based on the potassium‒lead system are used as liquid‒metal coolants in heat‒dissipating elements of fast neutron nuclear power plants. Due to the practical importance of this alloy, a semi‒empirical calculation of thermophysical characteristics (heat capacity, coefficient of thermal linear expansion, density, thermal conductivity, thermal diffusivity and specific electrical resistance) of potassium, lead and melt of lead with potassium was carried out. For calculations we used the arrays of experimental data coordinated with each other, relations of the author’s model of two‒phase local‒equilibrium region and the modified rule of mixing of components. In the formation of thermal properties of components and their alloys give as phenomena in any small neighborhood of the sample point (local level), and collective phenomena of reactions of all points of the alloy (substantive level) to temperature changes. The existence of features in the temperature dependences of potassium and lead in the form of peaks, pits and jumps, as well as the inheritance of some graphical features of the temperature curves of components in the formation of thermal properties of the melt are indicated. By means of approximation of the experimental data of the melt, the disappearance of some features during the formation of the alloy was established. On experimentally unexplored temperature intervals the behavior of thermophysical characteristics of components is demonstrated, and thermal properties of the melt are displayed in the form of tables. It is pointed out the necessity of additional experimental work to verify the calculations performed and to clarify the behavior of thermophysical characteristics of the components and their alloy at unexplored temperature intervals.