Thermomechanics of power reactor fuel elements

Analyzing the data of postreactor studies of fuel elements of the WWER type power reactors the calculational scheme of thermo-mechanical fuel-cladding interaction and deterministic technique for stressed-deformed state of large-scale fuel element model are developed. Account of friction forces between pellets non-axially located in a fuel element and fuel can appearing under transients in the reactor operation is the key point of the calculational scheme ad technique. The conclusion is made that the technique is applicable for practical calculations of stressed-deformed state of fuel elements in power reactors operating under stationary and variable conditions and satisfactory coincidence of calculational and experimental data on changes in forms of laboratory prototypes and WWER fuel elements testify to it. The calculational results explain nontrivial peculiarities of power reactor fuel element deformation