Structural investigation of fuel rods basing on dynamic model of heat flow phenomena in fuel assemblies

The structural investigation of reactor materials are usually by calculations determining the working conditions of particulars elements of fuel assemblies or the hole reactor core. For this analysis the mathematical model of heat flow phenomena was proposed which enable the calculations of temperature field within the assembly. The differential equations for mass, energy and momentum of cooling medium conservation in coaxial and transversal flow direction enable the steady state and transient analysis for the cases of change in heat flow in cooling medium velocity and the pressure in the assembly. The introduced empire correlation which are completing the set of equations make possible the analysis for violent changes of cladding temperature of fuel elements for cooling medium in two-phase flow. The computer program basing on the presented model was prepared for the calculations of initial parameters necessary for beginning the cladding and fuel material structural investigations. (author)