Analysis of the Phenix end-of-life natural convection test with SAS4A/SASSYS-1

From a reduced power and flow condition, the 2009 Phenix Natural Convection Test mimics a protected loss-of-heat sink event. The measured transient response of the Phenix reactor to such an event provides an important data set for validating safety analysis codes. A model of the Phenix reactor and primary coolant system was developed using the reactor safety analysis code system SAS4A/SASSYS-1. While the overall global response of the reactor was predicted reasonably well, there were some non-negligible discrepancies in the temperature predictions during the transient and work continues to improve the model. Some modeling issues have been identified, and will be addressed as improvements to the model continue. (authors)