Nuclear fuel element

A nuclear fuel element comprising an elongated composite cladding container of a zirconium alloy tube consisting of constituents, other than the zirconium, in amounts greater than about 5000 parts per million by weight and having a barrier lining of sponge zirconium metal in a thickness of from about 1 percent to about 30 percent of the thickness of zirconium alloy tube, metallurgically bonded to the inner surface of the zirconium alloy tube, a central core of nuclear fuel material disposed within and partially filling said lined tubular container so as to leave a gap between said container and fuel providing the core, said nuclear fuel material comprising an oxide of uranium which contains dispersed therethrough an additive of aluminum silicate in an amount of about 0.01 percent up to about 5 percent by weight of the fuel material.

A nuclear fuel element comprising an elongated composite cladding container of a zirconium alloy tube consisting of constituents, other than the zirconium, in amounts greater than about 5000 parts per million by weight and having a barrier lining of sponge zirconium comprising constituents, other than zirconium, in amounts ranging from about 1000 up to 5000 parts per million by weight, in a thickness of from about 5 percent to about 30 percent of the thickness of the zirconium alloy tube, metallurgically bonded to the inner surface of the zirconium alloy tube, a central core of nuclear fuel disposed within and partially filling said lined tubular container so as to leave a gap between said container and fuel providing the core, said nuclear fuel material comprising uranium dioxide which contains dispersed therethrough an additive of aluminum silicate in amounts of about 0.1 percent to about 1.0 percent by weight of the fuel material.