Thermal-physical substantiation of temperature conditions for fast reactor fuel assemblies taking into account overheating factors and tamperature fields

Results of the analysis of experimentally obtained temperature distributions over a fuel element perimeter in a central and near the wall zones of fast reactor hexagonal fuel assemblies (FA) are presented. Ways to generalize the experimental and calculational materials are shown and particular generalizing dependences for the maximum nonuniformities of temperature in deformed fuel element lattices for wide ranges of geometric parameter variations (deformation directions, FA with and without displacer, smooth and ribbed fuel elements, various gaps between FA shroud and fuel elements) are obtained. The method for calculating temperature distribution over fuel element perimeter in deformed lattices is presented. The method is tested using experimental material. Results of the calculational analysis of temperature fields in fast reactor FA point to a considerable effect of FA shape change on the temperature fields in fuel elemens and FA shroud. The methods of overheating factor calculation is specified due to considering the effects of interchannel exchange on coolant overheating. An approach to the calculation of thermal technical reliability of FA is described