Buoyancy driven flow in reactor safety

Abstract

Buoyancy driven flow is often found in many engineering applications such as the mixing process of fluids, which have different densities. The aim of this study is to simulate mixing of borated and unborated water, an issue which is relevant to the analysis of the safety of nuclear reactors. The degree of mixing of weakly and highly borated coolant is a critical issue with respect to reactivity of the reactor core. Therefore, a combined numerical and experimental study of buoyant mixing processes has been performed. The numerical studies on different types of grid show, that the main influence to the discription of the mixing processes is the simplifacation of the flow domain. In the case when the proper flow domain is used, a better agreement between the numerical and experimental results can be achieved.