Abstract: Disclosed are a fuel rod and a fuel bundle using the fuel rod. The fuel rod may include first enriched uranium in a boost zone of the fuel rod, wherein the boost zone may be arranged directly at a bottom of the fuel rod. The fuel rod may also include second enriched uranium in a second zone of the fuel rod, wherein the second zone is arranged over the boost zone. The fuel rod may also include natural uranium in a third zone of the fuel rod, wherein the third zone is arranged over the second zone. In this fuel rod, a percent of enrichment of the enriched uranium in the boost zone is at least one percent.

Abstract: Disclosed are a fuel rod and a fuel bundle using the fuel rod. The fuel rod may include first enriched uranium in a boost zone of the fuel rod, wherein the boost zone may be arranged directly at a bottom of the fuel rod. The fuel rod may also include second enriched uranium in a second zone of the fuel rod, wherein the second zone is arranged over the boost zone. The fuel rod may also include natural uranium in a third zone of the fuel rod, wherein the third zone is arranged over the second zone. In this fuel rod, a percent of enrichment of the enriched uranium in the boost zone is at least one percent.

Abstract: A method and system for demonstrating compliance of nuclear fuel rods with fundamental licensing criteria for fuel rod internal pressure during nuclear reactor operation is presented. A nuclear fuel rod evaluation process is performed during the fuel cycle design and licensing process for each operating cycle of a particular nuclear reactor. The evaluation process includes a rod-by-rod internal pressure analysis based on empirical data of actual operational power output levels of each fuel rod in the reactor core. A computer program constructs individual fuel rod power histories for each nuclear fuel rod in the reactor core based on empirical information acquired during previous fuel cycles and the projected operation of the reactor in an upcoming fuel cycle. Using the constructed power histories for each fuel rod, the program then computes thermal and mechanical overpower limits and a maximum internal pressure for each rod in the upcoming fuel cycle.

Abstract: A nuclear fuel bundle has differential peak power limits for the edge or peripheral fuel rods and the interior fuel rods. Also, the magnitude of nuclear fuel in the edge or peripheral rods is decreased in comparison with the magnitude of nuclear fuel in the interior rods. The nuclear reactor can thus operate at higher power output by decreasing the margins between the power outputs and peak power limit of the interior rods, as well as by decreasing the margins between the power outputs of the edge or peripheral rods and the increased peak power limit of those rods. The outer or peripheral edge rods can also be enriched for enhanced power output.

Abstract: In a nuclear reactor fuel bundle assembly having a plurality of fuel rods and a non-round water rod extending between upper and lower tie plates, and having at least one fuel rod spacer located along the non-round water rod, an improvement which includes cooperating components on the fuel rod spacer and on the water rod for permitting movement of the spacer along the water rod to a desired axial location and for thereafter preventing further axial movement of the spacer in at least one of two opposite axial directions, the cooperating components including at least one spring on one of the spacer and the water rod.

Abstract: A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced.

Abstract: In a fuel bundle having an array of fuel rods of 9-by-9 or greater, removal of the corner fuel rods from the array occurs. This removal enables the remainder of the array rod-to-rod pitch to be decreased. Further, and over this array with the corner fuel rod removed, a fuel bundle channel having rounded corners of increased radius of curvature or flattened corners imparting a broadly taped curvature is utilized. In both cases, the effective flat span of the fuel bundle sides is reduced with the result that the new fuel bundle incorporates improved resistance to channel bulge with improved critical power.

Abstract: In a fuel bundle for use in the core of a boiling water nuclear reactor, part length rods having a tendency to reduce pressure drop are used in combination with spacers and spacer attached devices tending to restore pressure drop to improve critical power. The addition of the part length rods has the advantage of lowering the pressure drop. Attached devices substantially recapture the pressure drop. Exemplary spacer attached mechanisms for the recapture of pressure drop are set forth including vanes--preferably swirl vanes on the spacers, decreasing the spacer pitch to increase the total number of spacers in the upper two phase region of the fuel bundle, increasing the vertical height of the spacers, and increasing the thickness of the metal from which the spacers are constructed. Two classes of separation devices are disclosed for placement in the volume overlying the end of the partial length fuel rods.

Abstract: A fuel bundle having spacers optimally deployed is disclosed wherein the distance between the spacers varies along the length of the fuel bundle. The fuel bundle has a dense fuel rod array (preferably in the range of 10.times.10). It includes at least one part length rod extending from the lower tie plate toward but not to the upper tie plate, which part length rod terminates at a spacer and defines under the upper tie plate overlying the end of the spacer a vent volume for the preferential venting of vapor moderator (steam) from the fuel bundle. A vertical spatial distribution of the spacers is disclosed in which the bottom spacers in the single phase region of the fuel bundle are relatively closely vertically spaced and the upper spacers are relatively more distantly vertically spaced one from another.

Abstract: The present invention relates to nuclear reactors and more specifically to a fuel bundle arrangement for a boiling water nuclear reactor in which so-called mixed oxide fuels including plutonium and uranium are utilized in a nuclear fuel bundle together with a burnable absorber such as gadolinium to optimize the reaction of a nuclear fuel bundle.

Abstract: The disclosed invention consists of a ceramic form of fuel for a nuclear reactor comprising an oxide of a fissionable element and containing therein a consumable neutron absorbing agent. The ceramic fissionable fuel product provides longer fuel performance in nuclear reactor service.