Nuclear reactor fuel assembly and method of forming same
AssigneeWestinghouse Electric Corp.
InventorsThomas M. Camden, Jr., Thomas R. Freeman
Life of this patent
Estimating the term…
Abstract
A nuclear fuel assembly, particularly advantageous for use in a pressurized water reactor, wherein each alternate fuel rod in the assembly is positioned with its fission gas plenum zone at the top of the assembly and the intervening alternate fuel rods are positioned with their fission gas plenum zones at the bottom of the assembly. All of the fuel rods are preferably axially coextensive. An axial blanket region may be formed by providing the fuel zone of each fuel rod with a small zone of natural or depleted uranium at a part of the fuel zone furthest from the fission gas plenum zone. A method of effectively lengthening the active length of a nuclear fuel assembly is also described.
Claims11
A nuclear fuel assembly comprising:
- a top nozzle assembly;
- a bottom nozzle assemble spaced from said top nozzle assembly
- a plurality of guild thimble tubes extending between said top and bottom nozzle assemblies;
- a plurality of spacer grid assemblies axially spaced along and attached to said guild thimble tubes;
- a plurality of fuel rods held in a spaced lateral array between said top and bottom nozzle assemblies by said spacer grid assemblies, each of said fuel rods comprising a fuel zone and a fission gas plenum zone wherein a first group of said fuel rods are disposed in said fuel assembly with said fission gas plenum zone adjacent said top nozzle assembly and a second group of said fuel rods are disposed in said fuel assembly with said fission gas plenums adjacent said bottom nozzle assembly and wherein the fuel zone of said first group of fuel rods is axially shifted with respect to the fuel zone of said second group of fuel rods.
A method for obtaining enhanced fuel utilization and for increasing the effective active length of a nuclear fuel assembly comprising an array of fuel rods, each fuel rod having a fuel zone and a fission gas plenum zone at opposite ends thereof, said method comprising the steps of:
- arranging a first group of said fuel rods in said fuel assembly with the fission gas plenum zones thereof at a top of said fuel assembly;
- arranging a second group of said fuel rods in said fuel assembly with the fission gas plenum zones thereof at a bottom of said fuel assembly;
- positioning the fuel rods in said fuel assembly to form a substantially axially coextensive array of fuel rods having top and bottom zones containing both fuel zones and fission gas plenum zones.
Dependencies are inferred from the claim text.