The main factor of destruction of fuel rods in accidents with loss of coolant is associated with the vapor-zirconium reaction occurring between the fuel rod shell and the coolant (water). Improving the reliability of fuel cells can be obtained by modifying or replacing the fuel shell, materials that do not interact with the coolant during normal operation and in emergencies. The loss of coolant accident is a design-basis accident in light water reactors. The postulated accident requires an analysis of the double guillotine break in a main primary coolant pipe, which allows the coolant to freely discharge out of the primary system into the containment of the building. In the present work, the heat stored in the active zone of the reactor, the heat capacity of the fuel and the shell temperatures are determined for ATF materials U-10Mo and U3Si2. The calculated values are compared with the usually used fuel UO2. The results showed beneficial effect of using ATF materials. The above quantities are decreased dramatically for ATF, promising to replace UO2 with ATF fuels. This reduces the probabilities of accidents and oxidation in the nuclear reactors. The calculations are done for nuclear power plant, type VVER-1200.

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Abstract.The results of the experimental study of the thermophysical properties of the coating formed by microarc oxidation (MAO) on an aluminum-silicon alloy AK12D are presented. Тhe description of the research methodology, including the formation of the MAO-layer on the surface of laboratory samples and the study of their structure, composition and of thermophysical properties are given. The thermal conductivity of the coating was investigated by two methods: steady state and laser flash method. The tests were performed within the temperature range of 50-400° C. The obtained results showed that the coating have a rather low thermal conductivity (λ= 1.32…1.52 W/(m⋅K) at 100 о С). It is shown that a wealth of mullite (up to 60%) does not lower the thermal conductivity of the coating. It is assumed that the basic factors affecting the thermal conductivity of the oxide layer are small-scale porosity, crystallite sizes and amorphous phase.