Multi-phase transport phenomena are ubiquitous in our lives and industrial applications alike. From the flow of river in nature, and the flow of blood and oxygen transport in human body to rocket propulsion and the functioning of a nuclear power plant etc., all can be categorised within the domain of multi-phase transport process. The term in itself is so general that anything that is happening in this universe within the limits of the classical physics can be considered as the multi-phase process. Given the such broadness of this topic, it can only be discussed from the perspective of a single domain. One such domain where this process plays a very important role is nuclear power industry. As a consequence of rising CO2 levels in the world there is a demand for the carbon-zero energy resources, which can completely phase out the non-green fossil fuels, and can produce electricity 24 × 7 throughout the year for several years without producing any CO2, and the only source of power which guarantees this at present is the nuclear energy. Thus, the phenomenology of nuclear power generation is a very evolved and interdisciplinary research field, and the phenomena of multi-phase transport plays a crucial role in it. Although the experiments investigating various multi-phase phenomena occurring in a nuclear power plant may be one of the approaches to enrich R&D in this domain but dealing with nuclear materials at very high temperatures at the scale of a nuclear reactor renders them far from being a viable option in most of the cases. This has lead to the use of Computational Fluid Dynamics (CFD) since it’s inception to carry out the analysis of the various aspects of nuclear reactor operation from plant designing to thermal-hydraulic studies during normal operating conditions as well as during Severe Accident (SA) conditions - like the one happened in Fukushima, Japan (2011). Thus, the aim of this talk is to give a brief insight into some of the recently developed mathematical models and numerics for the multi-phase CFD, and their application to the study of multi-phase transport phenomena occurring in the scenario of severe accidents, specifically the
Loss of Coolant Accidents (LOCA) in the nuclear power reactors.