Towards understanding melt eruption phenomena during molten corium concrete interactions

A defense-in-depth feature for advanced light water reactors to cope with beyond design basis accidents is the ability to cool and stabilize ex-vessel core melt debris. Several international experimental programs have investigated core-concrete interactions and debris cooling of ex-vessel core melts. These experimental programs have identified various phenomena which affect melt coolability and may enhance it. One such phenomenon, melt eruptions, occurs when gas from the underlying decomposing concrete entrains melt up through and onto a solidified crust, which separates the molten melt from the cooling water. Previous modeling and experimental work have shown this cooling mechanism can have a large impact on melt coolability. Previous melt eruption models are reviewed and a new synthesis model is proposed. Reviewing past experimental evidence and modeling efforts indicate the geometry of the flow area impacts the amount of melt ejected. To understand the potential flow area available for melt eruptions, past experimental evidence is reviewed, a steady state analysis of flow area is performed and non-steady state considerations are discussed.