Models of core melt behaviour after a postulated reactor vessel melt-through

In the unlikely event of reactor core debris melting through the reactor vessel after a postulated core meltdown it will contact the underlying substrate material. The subsequent behavior of the core-melt depends on the fractions of oxide fuel and stainless steel in the melt. Models for the penetration of an immiscible phase into a lower melting point substrate are developed and illustrative calculations presented. Factors where a more detailed understanding would enable the range of models considered to be reduced are indicated. 13 refs