The pressurizer is a device used to maintain proper pressure in the primary circuit (usually between 10-15 MPa). In order to do so pressurizer is built as a tall vessel filled halfway with primary circuit water. Pressurizer heaters will heat this water allowing the water to boil and creating steam pressure which affects the whole primary system. Pressure should always be enough that the water never boils in the primary circuit outside the pressurizer. As such the boiling temperature should always be higher than primary water temperature.
The primary circuit consists of two legs, one for the left side of the reactor, the other one for the right. The pressurizer is located in the left leg. There are several devices in the pressurizer:
- 4 Pressurizer heaters designed to heat water in the pressurizer and raise pressure via boiling.
- Makeup/drain to change water level in the pressurizer.
- 4 Relief valves to dump steam and lower pressure in emergencies.
- 2 Pressurizer sprays to cool down the steam by spraying cold water in it.
The pressurizer is also equipped with a very strong startup heater. As some PWRs can startup solely on decay heat, we have provided the startup heater to make the startup process quicker. It will heat the left leg of the primary circuit.