In-vessel melt-water interaction caused by the failure of the crust above the core support plate under molten pool. Pt. 1. Choice of the solution method

The first part of this work describes a methodology used to estimate the risk of melt water interaction for in-vessel scenarios. After presenting the available information for the admissible mechanical upper head impact energy and for the available thermal energy for the EPR several inherent limitations are discussed for transferring the available thermal energy into mechanical energy and to transport it up to the upper head. Finally a strategy is elaborated to apply the state of the art melt-water interaction analysis using the IVA5 computer code and, in addition, to estimate the maximum energy which can be transferred into mechanical energy. The strategy elaborated in Part 1 will then be applied in Part 2 for practical estimation of the risk of 4 selected scenarios for in-vessel meltwater interaction. (orig.)