Cooling and retention of fuel within the reactor vessel of the SNR-300 after power excursion accidents

Within the framework of the licensing procedure of the SNR-300 power plant in Kalkar it is being demonstrated that the reactor vessel, the primary piping system and the in-vessel immersion cooling system withstand the mechanical loads of an energetic accident and that the functionality of the decay- heat removal chain is maintained. The basic requirements for the long-term retention of the fuel within the vessel are thus fulfilled. In the present report the heat transport from the fuel to the decay-heat removal systems are investigated for various representative fuel distributions within the reactor vessel together with the local transient temperature fields within the fuel supporting structures. It is shown that the decay heat is removed by in vessel and external natural convection flows from the fuel to the active heat sinks