The maximum power removed by each RRP loop is about 5 to 7 MW(th), depending on operating conditions. The low amount of removed power ensures that, whatever the reactor power, it is possible to test the heat removal system while the reactor is in operation without significantly disturbing operating conditions. The abovementioned testing procedure is a significant element in validation of the reliability of such passive heat removal systems.

The RRPp are safety grade. The RRPa are safety grade, except for the chilled water loop and pumps. Normal residual heat removal system

In the reactor hot state, residual heat is removed through the steam generator. The steam is discharged to the atmosphere, and the steam generator is fed by the startup shutdown system (SSS). This system is not safety grade. At low temperatures, the RRP with the air-cooling tower (RRPa) removes decay heat.

When the reactor vessel is open, especially during refuelling operations, decay heat is removed by the twelve RRPa cooled by chilled water to secure a very low primary water temperature, compatible with the maintenance action conditions. The primary circuit operates on natural convection and the RRPa loops operate in an active mode (with forced circulation in the chilled water loop).

The safety injection system is the only active safety system of the SCOR; it is safety grade. A short description of this system is provided below.

Safety injection system

As large break LOCAs are eliminated by design, and as the primary system thermal inertia is larger than that of a loop type PWR, the safety injection system requires devices with a small flow rate. With the selected low pressure for the reactor, there is safety injection of only one with a pressure of about 20 bars. The pump power required for the safety injection is very small, about 35 kW(e).