Author(s)

R. Wittmaack

Abstract

Dynamic leak increase in a steel wall caused by corium discharge R. Wittmaack Siemens AG, KWUNDS1, Erlangen, Germany Abstract In a postulated core melt accident in a pressurized water reactor where molten corium accumulates on top of the core support plate, the heavy reflector wall fails due to thermal attack by hot corium. For steam explosion investigations the time-dependent area of the leak in the wall is an essential boundary condition. We analyse the increase of the leak size caused by the discharge of molten oxidic corium and stainless steel through the leak. The dynamics of the leak area, which we assume to be circular, is investigated analytically and numerically with the CORFLOW finite volume code. We show that the leak increase caused by oxidic corium discharge is of minor importance, whereas molten steel leads to significant wall erosion during the discharge process. Conservative analytical calculations of the steel discharge lead to radial erosion rates of about 5

Keywords