XIX-3.1. Primary circuit and its main characteristics

The SCOR is an integrated PWR with a compact primary circuit. The reactor pressure vessel houses the main primary system components including the core, pressurizer, steam generator, reactor coolant pumps, control rod drive mechanism (CRDM) and the heat exchangers of the decay heat removal system. This design configuration eliminates large penetrations in the reactor vessel, thus excluding the possibility of large break loss of coolant accidents.

The single steam generator acts as the reactor vessel head as shown in Figure XIX-1. The flow path of the reactor coolant is illustrated in this figure. From the lower plenum, water flows upward through the core and the riser and through the centre of the pressurizer.

In the upper portion of the vessel, the fluid flows upward and then downward inside the U tubes of the steam generator. Then the fluid is collected in an annular plenum and passes to the inlet of the reactor coolant pumps. From the pump outlet, the coolant flows through a venturi and then across the tubes of the decay heat exchangers to the lower plenum.

XIX-3.2. Core andfuel features

The core is similar to the core of French 900 MW(e) PWRs with 28% lower power density than the standard French PWR. The core consists of 157 assemblies of 264 fuel rods in a 17 x 17 square array, with an active fuel height of 3.667 m. The central position in each fuel assembly may be used for in­core instrumentation, and 24 positions have guide tubes for control rods. The core thermal power is 2 000 MW.

It is a soluble boron free core. The reactivity is controlled with integrated CRDM (control rod drive mechanism).