Publication
OFFBEAT is a 1D, 2D and 3D fuel behavior code under development at the École Polytechnique Fédérale de Lausanne (EPFL) and the Paul Scherrer Institute (PSI). In this paper, an incremental stress-strain solver with dynamic mesh update is presented and preliminary validated against the IFA-650.2 experiment performed at the Halden reactor in 2004. The experiment, in which the cladding ballooning typical of LOCA scenarios was artificially induced, lead to the fuel rod burst and to peak cladding temperatures of ~1090 °C. The inner rod pressure behavior and the cladding deformation profile at burst time are selected as quantities of interest for the validation procedure. In addition, the OFFBEAT results are compared with the calculations provided by BISON and TRANSURANUS simulations. The results show an adequate prediction of the fuel rod behavior during ballooning.