This is the third part of a three-part series of papers addressing the probability of liner failure in a Mark-I containment. The purpose is to quantify the corium/concrete interactions and liner attack phenomena in a form suitable for use in the probabilistic framework as discussed in the first part of this series. In the quantifications of corium/concrete interactions, the principal parameter of interest is the melt superheat transient, especially as it is affected by the oxidation of the metallic components in the melt. A computer code specifically developed for this purpose is also described and compared with available experimental data. In the quantification of the liner attack phenomena, the principal parameters are melt-to-liner heat transfer coefficient and liner failure criteria. The assessment of the heat transfer coefficient is based on experiments that simulate the melt-to-liner contact (recirculating) flow regime, which were specifically run for this purpose. The consideration of liner failure criteria includes finite element analyses addressing the potential for structural failure (due to loss of strength in high-temperature steel) in addition to straightforward failure by melting. The two-dimensional and transient aspects of the heat transfer problem, including solid-liquid phase change at the melt-liner interface, are shown to be important, and the quantification is carried out by means of an analysis tool specifically developed for this purpose.