Verification of the atmosphere response on sodium boiling in CONTAIN

This paper describes the scope and results of the verification effort focusing on the model for sodium boiling outside the reactor vessel. Hypothetical accident situations are conceivable when the core penetrates the vessel and falls together with sodium into a catchpan or on the floor of the reactor cavity. The computational models in CONTAIN involved in simulating coolant boiling situations are pool heat-up and pool boiling, thermodynamics of the atmosphere and mass flow between connected rooms. (orig./HP)