Comparison of Lumped Parameter and CFD Code Predictions: Sump Evaporation Phenomena

In nuclear reactor containment, Sump, Calandria Vault and Calandria Vessel contain large amounts of water. Condensation on walls and containment spray system actuation also results in accumulation of water in the containment sump during the accident conditions. Evaporation of water takes place during the accident conditions and needs to be accounted in the hydrogen distribution analysis. Lump parameter codes such as ASTEC have built-in models for sump water evaporation. However, CFD codes are being increasingly used for containment hydrogen distribution studies, development of a sump water evaporation model for multi-dimensional calculations is required. The sump model is implemented through mass and energy balance using two different approaches. The main focus of the paper is on the simulation of sump evaporation experiment conducted in TOSQAN facility using the lumped parameter code and its comparison with the CFD results and the available experimental data.