Modelling of multi-physics phenomena in fast reactor design; Safety and experimental validation

Ninokata, Hisashi*; Pellegrini, M.*; Kamide, Hideki ; Ricotti, M.*

The paper provides a cursory look at current approaches in numerical modeling 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 programs, 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 numerical simulations of these multi-physics 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 more quantitative validation basis with identification of errors and/or uncertainties based on the Bayesian rule.