Since the Fukushima accidents, severe accident mitigation as a last protective barrier of nuclear disasters is of a great concern for the public acceptance. A lot of efforts have been made to resolve the severe accident mitigation issues during the several decades. Corium stabilization inside and outside the reactor vessel, one of the issues with a great progress, is a key to securing the safety of Light Water Reactor from the point of view of severe accident mitigation and containment integrity. It is noted that several organizations in the world are still doing a lot of researches for the final resolution of this issue and international workshops are actively held often. This special issue of the journal aims at providing high quality articles containing original research results and will let the readers of this journal know more about recent research results and new developments in this area.

Potential topics include but are not limited to the following:

• In-vessel accident progression
• In-vessel corium pool stratification and cooling
• Interaction of corium and vessel material
• Lower vessel failure mechanism
• Ex-vessel steam explosion
• MCCI and basemat failure
• Ex-vessel particulate bed spreading and formation
• Ex-vessel corium pool cooling
• Ex-vessel corium retention and stabilization (core catcher)
• Severe accident sequence analysis