Figure 2 shows the general arrangement of the reactor pressure vessel and its internal structures. The core is low down in the vessel. Helically coiled once through steam generator is located between the core support barrel(CSB) and reactor vessel. Thermal shields are provided below the steam generator surrounding the core to reduce the neutron fluence level on the reactor vessel. There are four main coolant pumps installed on the reactor vessel above the steam generators. The upper plenum of the vessel forms a pressurizer to maintain the operating pressure.

MS/FWS	CCS

The primary coolant flows up through the core and CSB riser, through the pumps, down through the steam generator and back to the lower plenum under the core. The current design is capable of 50% of full power operation only with natural circulation.