Patent ID: 8744035

Claim:
A power module comprising: a reactor vessel containing a coolant; a reactor core disposed in the reactor vessel and submerged in the coolant; a riser section disposed in the reactor vessel above the reactor core, the riser section comprising one or more outer walls defining an inner passageway; a coolant deflector shield comprising an ellipsoidal surface, the coolant deflector shield being disposed in the reactor vessel at a position above an open end of the inner passageway; a pressure control assembly, positioned in the reactor vessel in a pressurizer region between the coolant deflector shield and an upper end of the reactor vessel, to control a pressure in the pressurizer region, the pressure control assembly comprising one or more heaters positioned on opposite sides of the reactor vessel within the pressurizer region; and a fluid passageway that extends between the heaters from the coolant deflector shield to the upper end of the reactor vessel and is fluidly coupled to gaps between an inner surface of the reactor vessel and distal ends of the ellipsoidal surface for a flow of coolant from the riser section into the pressurizer region and through the fluid passageway.