Recommendations and supporting information on the choice of zirconium oxidation models in severe accident codes

Fuel rod cladding oxidation is one of the key aspects of the accidental behaviour of LWR fuel elements, and a comprehensive base of experimental information on its kinetics is available. However, the conventional treatment of zirconium oxidation kinetics in some severe accident (SA) codes is unsatisfactory compared to the more recently implemented highly sophisticated core degradation models. Based on a review of experimental results recommendations for application are given in the report, in order to promote the acceptance of a common data base for all SA codes. Convergence towards this goal helps to avoid arbitrary user options and allows the focussing of code-to-code benchmarking comparisons to fields of actual and future concern.