Status of precalculations and interpretation of the first two phebus FP tests

摘要

This paper summarises the main results at the time of writing from the analysis of the Phebus FP severe accident experiments. While the overall picture expected from precalculations is confirmed, there are many important questions of detail. Better understanding of the later phases of core degradation is needed to explain the experimental data. Chemical speciation and physical resuspension effects on fission product transport appear important but are hard to predict. Aerosol deposition in the containment is much influenced by flow patterns, and iodine chemistry is strongly affected by the presence of other materials. Results from the first two tests with different fuel burnups should help clarify the many interacting mechanisms behind the test data.