Rogankov O. Metallic fluid carriers: phase diagram and transport coefficients of alkali and alkaline earth metals

Thesis research is devoted to the study of stages of work and the optimal choice of coolants for autonomous nuclear reactors of high power. Cascade scheme for converting high-potential thermal energy of the reactor to a given level of its consumption in mechanical and electrical forms is proposed. It is formed by sequence of alternating heat pipes and Stirling engines. The issues of safe operation of each of the elements of the cascade, taking into account modern requirements for environmental protection, are considered as priorities. The manuscript proves the principal possibility of increasing the working pressure and the specific power of pumping the coolant through the use of loop heat pipes. Self-regulation of the speed of movement of various vapor-liquid flows and the proposed modification of the “compensation chamber - porous wick” system is claimed. It plays the role of an efficient capillary pump, which ensures not only the intensification of pumping, but also the adaptation of its speed to potentially possible abrupt changes in the heat removal conditions of the reactor core. Thesis research comprehensively substantiated and confirmed by quantitative estimates the prospects of the transition in Stirling engines to the use of working fluids with a changing phase composition in the interphase region. This proves their competitiveness in comparison with the traditional operation of Stirlings on gaseous helium and hydrogen, compressed to enormous pressures at very high temperatures, which increases the risk of coolant leakage. A method for re-establishing of a congruent vapor-liquid diagram has been developed and brought up in the work to recommendations for practical use. It makes possible to predict effectively and with high accuracy the entire complex of thermo-physical properties of both the vapor interphase and the region of homogeneous coexisting phases. An adequate description of the properties of ten alkaline (Li, Na, K, Rb, Cs) and alkaline earth metals was proposed. It made possible to clarify a number of fundamentally important characteristics in monographs and reference books published so far.