A cold-leg LOCA in PIUS

The PIUS reactor is a pressurized water reactor with passive safety features. It is based on a concept developed and verified at ABB Atom during the last 10 yr. The basic design of PIUS features core degradation protection by connecting the core to a large pool of highly borated water to form a natural circulation loop. During normal operations, the hydraulic balance is maintained between the primary coolant loop and the reactor pool by controlling the main coolant pumps. During inadvertent conditions, when the hydraulic balance cannot be maintained, the borated pool water will enter the primary coolant loop to shut down the reactor, and a natural circulation path will be established to provide long-term cooling for the core