Analysis of a Station Blackout Scenario With The Atlas Data

A station blackout experiment named SBO-01 was performed at the ATLAS facility. From the SBO-01 test, the station blackout scenario can be characterized by two typical phases: The 1st phase characterized by decay heat removal through secondary safety valves until the SG dryouts; The 2nd phase characterized energy release by blowdown of the primary system after the SG dryouts. During the 2nd phase, some physical phenomena of the change over a pressurizer function, the pressurizer being full before the 1st POSRV opening, and the termination of normal natural circulation flow were identified. And finally, the PCT occurred at low core water level although under a significant amount of the PZR inventory, whose drainage seemed to be hindered due to the pressurizer function by the RV. The transient of SBO-01 is well reproduced in the calculation using MARS code