Fuel assembly having a shared fission gas plenum

A fuel assembly for use in a nuclear reactor, the nuclear reactor having a vessel and coolant situated within the vessel, wherein the fuel assembly defines a longitudinal axis, a first end, and a second end, wherein the second end is positioned above the first end when the fuel assembly is located within the nuclear reactor, and wherein the fuel assembly comprises:

• a first portion positioned adjacent the first end, the first portion comprising:
• an elongate duct configured to permit the coolant to pass therethrough;
• a plurality of fuel elements positioned within the elongate duct, wherein each fuel element comprises nuclear fuel material situated therein;
• and
• an upper end fitting comprising a plurality of gas flow pathways formed therein and a plenum header connection in fluid communication with the gas flow pathways, the upper end fitting positioned above the plurality of fuel elements, wherein the nuclear fuel material of the plurality of fuel elements is in fluid communication with the plurality of gas flow pathways;
• and
• a second portion positioned adjacent the second end, the second portion comprising a fission gas storage tank in fluid communication with the plurality of gas flow pathways and the plenum header connection of the upper end fitting, wherein the fission gas storage tank is configured to store an amount of fission gas generated by the nuclear fuel material during operation of the nuclear reactor, and wherein the fission gas storage tank penetrates a top most surface of the coolant such that a first portion of the fission gas storage tank is positioned above the top most surface of the coolant and a second portion of the fission gas storage tank is positioned below the top most surface of the coolant;
• and
• a plurality of coolant outlets for directing the entirety of the flow of coolant out of the fuel assembly below the fission gas storage tank, wherein the coolant outlets are longitudinally positioned between the fission gas storage tank and the upper end fitting.