Abstract
The lack of experimental data concerning the long-term 2-dimensional concrete ablation by a prototypic core oxide melt initiated the OECD-sponsored series of CCI experiments at ANL (USA). Complementary experiments (COMET) which were sponsored by the European Commission were conducted within the LACOMERA project at FZK (Germany). The CCI-2 test investigated the long-term interaction of a heated (direct electrical heating) core oxide melt within a rectangular limestone/common sand (LCS) concrete crucible. In absence of crusts the lateral/axial erosion ratio for oxide melts is approximately 1. However, crusts which can more easily develop in oxide melts may in case of a local crust failure lead to an irregular cavity shape as observed in the CCI-1 and CCI-3 experiment. The experiment COMET-L2 was designed to investigate a long-term MCCI of metallic corium in cylindrical siliceous concrete cavity under dry conditions with decay heat simulation of intermediate power, and subsequently at reduced power. During the first 100 s, i. e. until the end of the melt overheat, the ratio of the axial to the lateral erosion is approx. 1. The long-term axial erosion became more pronounced and was a factor of 2-3 higher than the lateral ablation. This is in agreement with results obtained in the former BETA experiments. Both series of experiments provided valuable data for code (WECHSL) validation and model improvements. The current version of WECHSL code is applied to the COMET-L2 and CCI-2 experiment.
