Containment Cooler Performance in the Presence of Light Non Condensable Gas with Cooler Location as a Primary Parameter

Abstract

Modeling of steam condensation caused by the operation of a cooler in a containment poses certain challenges. Consequently, the calculated gas flow and the gas distribution in the containment during test scenarios representative of severe accident sequences must be validated against experimental data. Such validation experiments were conducted in the PANDA facility (Switzerland) in the frame of the OECD/SETH-2 project. The performance of the containment cooler was evaluated for two configurations, designated middle and top position, corresponding to the location of the cooler in the containment during a 3-time-phase injection of steam, steamhelium and steam. For the middle position, the results show a deterioration of the cooler performance caused by the accumulation of helium in the cooler-casing which partially blocks the flow path through the cooler. This is followed by a recovery associated with the release of helium from the cooler-casing and the formation of a stable stratified layer on top of the vessel. For the top position a weak degradation of the performance and formation of stable helium rich layer in the center of the vessel was observed.