Failure mode of a concrete cylinder due to attack by an eroding melt while cooled by outside water

In the BETA facility an experiment was conducted on the failure of a cylindrical concrete wall which is eroded on the inner side by a heated melt while being cooled outside by stagnant water. No decrease of the radial erosion velocity is observed when the melt front approaches the outer concrete surface and wall failure occurs after the residual wall thickness is reduced to less than one centimeter. The melt relocates into the water annulus and fast evaporation of the water and pressure increase occur. Applicability of the experimental results for LWR severe accidents is discussed. (orig.)