Fuel Failures Recent Experience and Their Mitigation: A US Perspective

As part of the Tractebel contribution to the IAEA FUMAC project, Tractebel has used the updated FRAPTRAN-TE-1.5 code for simulation of selected Halden LOCA tests IFA-650.9 and IFA-650.10, together with the improvement in the thermal hydraulic modelling by using the imposed thermal hydraulic boundary conditions from SOCRAT calculations and in the thermal boundary conditions (axial power profile, plenum temperature). In particular, the impacts of the model improvements such as the Quantum Technologies' axial relocation model and errors corrections in the adapted FRAPTRAN-TE-1.5 version on the calculation results were identified and discussed. In addition, the statistical uncertainty and sensitivity analysis has been performed on the FRAPTRAN-TE-1.5 modelling of the selected Halden LOCA test IFA-650.10, which helped the identification of significant input parameters for LOCA fuel Behaviour modelling. The final objective is to apply the qualified fuel rod transient analysis codes FRAPCON/FRAPTRAN to develop an efficient methodology for assessing the performance and quantifying the margins for advanced technology fuel (ATF) designs under design basis accident conditions (in particular LOCAs). (author)