Patent ID: 7715518

Claim:
A method of producing a cladding tube for nuclear fuel for a nuclear boiling water reactor, which method comprises the following steps: forming a tube comprising: an outer cylindrical component comprising a first composition comprising a zirconium-based alloy; and an inner cylindrical component metallurgically bonded to the outer component, wherein the inner component comprises a second composition comprising 0.1 to 0.4 percentage by weight Sn, 400 to 1500 ppm Fe, less than 600 ppm O and the rest Zr, except for impurities of a content that does not exceed that which is normally accepted in Zr or Zr-alloys for applications in nuclear reactors, wherein the first and second compositions materially differ from each other, and wherein the second composition has a lower recrystallization temperature than the first composition; rolling the tube; and finally annealing the cladding tube at a temperature and a time that results in a first degree of recrystallization of the outer component and a second degree of recrystallization of the inner component, wherein the second degree is at least 97 percent and wherein the first degree is less than the second degree and higher than 50%.