Pressure-tube reactor with pressurized moderator

A nuclear reactor comprising:

• a) a pressure vessel for containing a pressurized moderator at a first pressure that is between about 5 MPa and about 25 MPa;
• b) a coolant inlet plenum disposed at one end of the pressure vessel and having at least one inlet port for receiving a coolant fluid, the coolant inlet plenum comprising an inlet plenum upper wall, an inlet plenum lower wall spaced apart from the inlet plenum upper wall in a first direction and an inlet plenum sidewall extending therebetween;
• c) a coolant outlet plenum disposed within the coolant inlet plenum, the coolant outlet plenum comprising an outlet plenum upper wall, an outlet plenum lower wall spaced apart from the outlet plenum upper wall and an outlet plenum sidewall extending therebetween, and wherein the outlet plenum lower wall is spaced between the inlet plenum lower wall and the outlet plenum upper wall in the first direction;
• d) a plurality of fuel channels for a coolant fluid at a second pressure and fluidly connected at inlet ends thereof to the coolant inlet plenum, the fuel channels adapted to receive nuclear fuel bundles and to be mounted within the pressure vessel and surrounded by the moderator, and outlet ends thereof being fluidly connected to the coolant outlet plenum to enable the coolant fluid to circulate from the coolant inlet plenum through the fuel channels to the coolant outlet plenum;
• e) the plurality of fuel channels maintaining separation between the coolant fluid circulating within the fuel channels and the moderator.