The SCOR pressurizer is integrated into the upper part of the riser, just below the steam generator. The pressurizer region is designed as an annular shape in the form of an inverted U, see Figure XIX-1. The coolant flows through the central part of the pressurizer. The bottom portion of the inverted U contains the opening to allow water insurge and outsurge to/from the pressurizer region

The electric heaters are located in a small volume tank outside the reactor vessel and act as a steam source. The cold water supply is tapped off just downstream the pumps and the two-phase mixture is reinjected at the top of the pressurizer.

Owing to the low pressure and low temperature operating point leading to smaller variations of water density versus temperature, the volume of the pressurizer is smaller than those used in plants with a classical, separate, pressurizer vessel. The SCOR pressurizer has a total volume of ~21 m3. This volume is large enough to manage a blackout without steam release through the safety valve of the pressurizer.