Patent ID: 7570728

Claim:
A nuclear fuel rod for a boiling water nuclear reactor, comprising: a cladding tube, defining a closed inner space and which is manufactured from at least one of the materials in the group zirconium and a zirconium-based alloy, the material of the cladding tube comprising a plurality of sites in which hydrogen is capable of being adsorbed; a plurality of nuclear fuel pellets, arranged in the inner space in the cladding tube so that the nuclear fuel pellets fill pan of the inner space; an initial fill gas arranged in the closed inner space in order to fill the rest of the inner space; wherein the initial fill gas contains a proportion of inert gas and a proportion of carbon monoxide, the carbon monoxide being located in the sites in which hydrogen is capable of being adsorbed, thereby blocking the sites; and wherein the internal pressure (P fill ) of the initial gas in the nuclear fuel rod amounts to at least about 7 bar (abs) at room temperature (T R ) and the proportion of carbon monoxide is at least 4.7 volume percent of the initial fill gas; and wherein the cladding tube has an inner surface that faces the inner space and the material in the cladding tube nearest the inner surface is pre-oxidized to provide a surface layer that comprises zirconium oxide.