Abstract: An improved fuel element for use in a nuclear reactor comprised of a central core of nuclear material, which is surrounded by a composite cladding. The cladding has an outer metallic tubular portion comprised of well-known cladding alloys used for such purposes. Metallurgically bonded to the outer metallic tubular portion is a commercially pure zirconium microalloyed with a controlled quantity of iron. The zirconium microalloyed with iron produced an inner metallic barrier having a beneficial balance between stress corrosion crack resistance and corrosion resistance while retaining other beneficial properties of pure zirconium, such as ductility.

Abstract: The present invention provides a creep resistant zirconium alloy comprising a coarse grained lath alpha microstructure. The microstructure can include small second phase precipitates. The small second phase precipitates can have a diameter less than 0.15 &mgr;m. The microstructure can be partially recrystallized. The microstructure is an acicular structure and can include a lath spacing within the range from about 0.5 to about 3.0 &mgr;m. The microstructure is an acicular structure and can include a lath spacing within the range from about 0.5 to about 3.0 &mgr;m. The present invention provides a nuclear fuel cladding comprising an annular layer of the creep resistant zirconium alloy.

Abstract: An improved fuel element for use in a nuclear reactor comprised of a central core of nuclear material, which is surrounded by a composite cladding. The cladding has an outer metallic tubular portion comprised of well-known cladding alloys used for such purposes. Metallurgically bonded to the outer metallic tubular portion is a commercially pure zirconium microalloyed with a controlled quantity of iron. The zirconium microalloyed with iron produced an inner metallic barrier having a beneficial balance between stress corrosion crack resistance and corrosion resistance while retaining other beneficial properties of pure zirconium, such as ductility.

Abstract: An improved fuel element for use in a nuclear reactor comprised of a central core of nuclear material, which is surrounded by a composite cladding. The cladding has an outer metallic tubular portion comprised of well-known cladding alloys used for such purposes. Metallurgically bonded to the outer metallic tubular portion is a commercially pure zirconium microalloyed with a controlled quantity of iron. The zirconium microalloyed with iron produced an inner metallic barrier having a beneficial balance between stress corrosion crack resistance and corrosion resistance while retaining other beneficial properties of pure zirconium, such as ductility.

Abstract: In a zirconium-alloy fuel element cladding, a method for generating regions of coarse and fine intermetallic precipitates across the cladding wall is provided. The method includes steps of specific heat treatments and anneals that coarsen precipitates in the bulk of the cladding. The method also includes at least one step in which an outer region (exterior) of the cladding is heated to the beta or alpha plus beta phase, while an inner region (interior) is maintained at a temperature at which little or no metallurgical change occurs. This method produces a composite cladding in which the outer region comprises fine precipitates and the inner region comprises coarse precipitates.