FIG. 22 illustrates a cross-section view of an embodiment of a reactor 2200 utilizing a circulating reflector material. The illustration shows the half of the reactor 2200 from the center to the left edge of the containment vessel 2218. The reactor 2200 includes a reactor core 2204 defined by an upper reflector 2208A, a lower reflector 2208B and an inner reflector 2208C. In the embodiment shown, the lower reflector 2208B also extends laterally and up the sides of the containment vessel 2218 for added protection to the vessel head 2238. The primary heat exchanger 2210 configured to have shell-side coolant flow (illustrated by dotted lines 2214), the coolant entering through a coolant inlet channel 2230 and heated coolant exiting from coolant outlet channel 2236. In the embodiment shown, fuel flows (illustrated by dashed lines 2206) from the reactor core 2204, via an upper channel through the inner reflector 2208C, and into the heat exchanger 2210 through the inlet tube sheet 2232. After passing through the tube set, the now-cooled fuel exits the lower tube sheet 2231 and flows back into the reactor core 2204 via a lower channel through the inner reflector 2208C. Flow of the fuel is driven by a pump assembly 2212 that includes an impeller in the fuel circuit (in this embodiment illustrated below the lower tube sheet 2231) connected by a shaft to a motor (in this embodiment located above the upper reflector 2208A).
