Outcomes of the French ICE program on Liquid Fragmentation in Severe Nuclear Accidents
During a severe nuclear accident involving nuclear core melting, one of the risks is the development of a vapor explosion (a detonation involving the rapid release of thermal energy). It is usually thought to occur in two stages : a premixing stage where a jet of hot corium fragments in the coolant (water for Pressurized Water Reactor) and an explosion phase where droplets generated by the premixing are fragmented by a trigger that generates a quick fragmentation and heat release allowing for the transition to a vapor detonation wave.
The goal of the presentation is to show advances that have been obtained in liquid fragmentation modeling in this context. Experiments and numerical simulations are made without vapor production and the focus has been put on the mechanical fragmentation mechanism. Classically, the presentation will focus first on the single droplet fragmentation mechanism (or secondary atomization) and will go on with jet fragmentations (or primary atomization). The influence of instabilities and turbulence on the triggering mechanism and droplet PDF will be discussed.
Contact Nathanaë l Machicoane for more information or to schedule a discussion with the seminar speaker.