Abstract: A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.

Abstract: Annular metal fuel and fuel rods are described that have improved performance over uranium oxide fuel rods. The annular metal fuel can be made out of porous metal nuclear fuel and will generate more power and operate at a much lower temperature than uranium oxide fuel. The annular metal fuel rods may be used in traveling wave reactors and other fast reactors. Pressurized water reactors may also be retrofit with annular metal fuel rods to improve reactor performance.

Abstract: A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.

Abstract: A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.

Abstract: This disclosure describes fuel-cladding chemical interaction (FCCI) resistant nuclear fuel elements and their manufacturing techniques. The nuclear fuel elements include two or more layers of different materials (i.e., adjacent barriers are of different base materials) provided on a steel cladding to reduce the effects of FCCI between the cladding and the nuclear material. Depending on the embodiment, a layer may be the structural element (i.e., a layer thick enough to provide more than 50% of the strength of the overall component consisting of the cladding and the barriers) or may be more appropriately described as a liner or coating that is applied in some fashion to a surface of the structural component (e.g., to the cladding, or to a structural form of the fuel).

Abstract: A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.

Abstract: Disclosed embodiments include fuel assemblies, methods of making a fuel element, and methods of using a fuel element.