Modelling of Multi-Physics Phenomena in Fast Reactor Design: Safety and Experimental Validation

The paper provides a cursory look at current approaches in numerical modelling and simulation of typical multi-physics phenomena of concern relevant to the sodium cooled fast reactor design and safety. Emphasis is placed on the methods that are in practice and their verification and validation programmes, including for those of fluid–structure thermal interactions due to thermal striping, thermodynamics of sodium–water chemical reactions, multi-component and multi-phase flows in the fuel degradation and core meltdown phases. Several of the numerical simulations of these phenomena are shown with verification and validation programs that employ not only separate effect small scale experiments of clean geometry but also for large scale integral tests or mock-up experiments. The last part of this paper will be spent on discussions on a more quantitative validation basis with identification of errors and/or uncertainties based on the Bayesian rule.