Patent Number: 040295451
Section: abstract

An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel has a composite cladding container comprising an outer layer having two coatings on the inside surface with the first coating on the outer layer being a diffusion barrier and the second coating on the first coating being a metal layer. The diffusion barrier is comprised of chromium or a chromium alloy, and the metal layer is selected from the group consisting of copper, nickel, iron and alloys thereof. The nuclear fuel element comprises a container of the elongated composite cladding, a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, an enclosure integrally secured and sealed at each end of said container and a nuclear fuel material retaining means positioned in the cavity. The metal layer and the diffusion barrier of the composite cladding prevent perforations or failures in the outer layer of the cladding from stress corrosion cracking or from fuel pellet-cladding interaction or both. The outer layer of the composite cladding is selected from conventional cladding materials and preferably is a zirconium alloy.