Fuel assembly having a shared fission gas plenum
A fuel assembly for use in a nuclear reactor comprising a fuel bundle, a plenum header connection positioned on the fuel bundle, a mast extending from the fuel bundle, and a common fission gas plenum extending from the mast is disclosed. The reactor includes a vessel and coolant situated within the vessel. The fuel bundle comprises a plurality of fuel elements including nuclear fuel material positioned therein. The plenum header connection comprises a plurality of passageways defined therein that are in fluid communication with the nuclear fuel material. The elongate mast comprises an internal passage connecting the common fission gas plenum to the plurality of passageways of the plenum header connection such that the common fission gas plenum is configured to receive an amount of fission gas generated by the nuclear fuel material during operation. The common fission gas plenum is positioned in an otherwise unused portion of the vessel.
1 . 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.
2 . The fuel assembly of claim 1 , wherein the fuel assembly comprises a third portion positioned intermediate the first portion of the fuel assembly and the second portion of the fuel assembly, and wherein the third portion of the fuel assembly includes a passage that places the first portion of the fuel assembly and the second portion of the fuel assembly in fluid communication with one another.
3 . The fuel assembly of claim 2 , wherein the first portion of the fuel assembly comprises a first outermost surface defined within a first diameter, wherein the second portion of the fuel assembly comprises a second outermost surface defined within a second diameter, and wherein the third portion of the fuel assembly comprises a third outermost surface defined within a third diameter that is smaller than the first diameter.
4 . The fuel assembly of claim 3 , wherein the third diameter is smaller than the second diameter.
5 . The fuel assembly of claim 2 , wherein the plenum header connection is configured to fluidly connect the plurality of gas flow pathways of the upper end fitting to the passage of the third portion of the fuel assembly.
6 . The fuel assembly of claim 1 , wherein the upper end fitting comprises a plurality of coolant flow channels defined therein, the coolant flow channels permit the coolant situated within the vessel to flow therethrough.
7 . The fuel assembly of claim 1 , wherein the upper end fitting comprises a plurality of plenum flow connection openings defined therein, and wherein the plurality of fuel elements are in one-way fluid communication with the plurality of plenum flow connection openings of the upper end fitting.
8 . The fuel assembly of claim 1 , further comprising a pipe defining an internal passage, wherein the internal passage places the fission gas storage tank and the upper end fitting in fluid communication with each other, and wherein the pipe defines a longitudinal centerline axis that is coincident with the longitudinal axis defined by the fuel assembly.
9 . The fuel assembly of claim 1 , wherein the fuel assembly defines an internal passage that places the plenum header connection and the fission gas storage tank in fluid communication with each other, and wherein the internal passage defines an inner diameter that is smaller than an inner diameter defined by the fission gas storage tank.
10 . The fuel assembly of claim 1 , wherein the fuel assembly defines an internal passage that places the plenum header connection and the fission gas storage tank in fluid communication with each other, and wherein the fission gas storage tank is in one-way fluid communication with the internal passage such that the amount of fission gas stored in the fission gas storage tank is prevented from back-flowing into the internal passage.
11 . The fuel assembly of claim 1 , wherein a longitudinal centerline axis defined by the plenum header connection is coincident with the longitudinal axis defined by the fuel assembly.
12 . 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 a first portion of the fission gas storage tank is positioned above a 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.
13 . The fuel assembly of claim 12 , wherein the fuel assembly comprises a transport pipe positioned intermediate the first portion of the fuel assembly and the second portion of the fuel assembly, the transport pipe defining an internal passage, wherein the internal passage places the fission gas storage tank and the plenum header connection in fluid communication with one another, and wherein the transport pipe defines a longitudinal centerline axis that is coincident with the longitudinal axis defined by the fuel assembly.
14 . The fuel assembly of claim 13 , wherein the first portion of the fuel assembly comprises a first outermost surface defined within a first diameter, wherein the second portion of the fuel assembly comprises a second outermost surface defined within a second diameter, and wherein the transport pipe of the fuel assembly comprises a third outermost surface defined within a third diameter that is smaller than the first diameter.
15 . The fuel assembly of claim 14 , wherein the third diameter is smaller than the second diameter.
16 . The fuel assembly of claim 13 , wherein the plenum header connection is configured to fluidly connect the plurality of gas flow pathways of the upper end fitting to the passage of the transport pipe of the fuel assembly.
17 . The fuel assembly of claim 12 , wherein the upper end fitting comprises a plurality of coolant flow channels defined therein, the coolant flow channels permit the coolant situated within the vessel to flow therethrough.
18 . The fuel assembly of claim 12 , wherein the upper end fitting comprises a plurality of plenum flow connection openings defined therein, and wherein the plurality of fuel elements are in one-way fluid communication with the plurality of plenum flow connection openings of the upper end fitting.
19 . The fuel assembly of claim 12 , wherein the fuel assembly defines an internal passage that places the plenum header connection and the fission gas storage tank in fluid communication with each other, and wherein the internal passage defines an inner diameter that is smaller than an inner diameter defined by the fission gas storage tank.
20 . The fuel assembly of claim 12 , wherein the fuel assembly defines an internal passage that places the plenum header connection and the fission gas storage tank in fluid communication with each other, and wherein the fission gas storage tank is in one-way fluid communication with the internal passage such that the amount of fission gas stored in the fission gas storage tank is prevented from back-flowing into the internal passage.
21 . The fuel assembly of claim 12 , wherein a longitudinal centerline axis defined by the plenum header connection is coincident with the longitudinal axis defined by the fuel assembly.