One-dimensional models of boiling and dryout

A time dependent model of boiling in a self-heated debris bed for the use in predictive computer codes is developed from basic physical laws and accepted phenomenological models of flows through porous media. The steady solutions have different forms depending on the presence or otherwise of capillary pressure. Sufficient flow through the permeable base alters the forms of solution and the approach to dryout. The inclusion of fluid inertia has only quantitative effects, depressing the dryout heat flux. (DG)