ETD

• sodium bubble

This work deal with the analysis of phenomena of sharp vaporization that may occur in the presence of a metastable superheated liquid. This phenomenon is of major interest for the safety analyses of sodium cooled reactors. Indeed, it is suspected to be at the origin of negative reactivity scram occurred in the Phénix reactor at the end of the eighties. The expansion and the collapse of a two phase bubble are addressed by theoretical considerations and the development of a computational tool. The validation of the computational tool, including several parameters, is achieved against experimental data of water bubble. The adaptation of the model to sodium bubble is therefore discussed and a preliminary study is carried out aiming at estimating the size, the duration and the expansion work of the bubble for different superheating temperatures. Suggestion for future development of the model and future activities are finally drawn.