Synthesis of spent fuel pool accident assessments using severe accident codes

This paper presents the results of various assessments of SFP accidents performed with different severe accident codes for different SFP geometries. In these studies, both loss of cooling and loss of water transients were analyzed. These calculations have been performed in the framework of the SARNET2 project. The analysis of these different SFP scenarios was conducted to identify some limits and needs for improvement of the SA code developed and usually used for reactor applications. More specifically, some questions about the SA code capabilities to evaluate the impact of air flow on coolability of the fuel assemblies (FAs) and the rate and path of air/steam flow in these FAs, have arisen. This work has also enabled us to identify the need to improve the knowledge and the models related to the effect of mixed air/steam atmospheres, especially the role of nitrogen on the acceleration of the corrosion rate of Zircaloy claddings and on the degradation of their mechanical properties.