Analysis of fuel behavior in power-ramp tests by FEMAXI-IV code

FEMAXI-IV is a computer code to analyze the thermal and mechanical behavior of a fuel rod during steady-state and transient conditions. FEMAXI-IV calculates the stress and strain distributions in the fuel and cladding due to the pellet-cladding mechanical interaction using the two-dimensional axisymmetric finite element method. It also calculates the fission gas release using a simplified physical model. Two of the most important phenomena relating to cladding failure are the pellet-cladding mechanical interaction and the release of fission gas into the gap between fuel and cladding. Using the FEMAXI-IV code, the fuel behavior obtained in the Studsvik power ramp experiments has been analyzed and the several important parameters affecting cladding failure have been studied. (author)