Patent ID: 8320515

Claim:
A water reactor fuel cladding tube for a pressurized water reactor, said cladding tube comprising an outer layer of a first zirconium based alloy and having directly metallurgically bonded thereto an inner layer of a second zirconium based alloy, wherein the cladding tube does not have any further zirconium based alloy layer, wherein the inner layer is adapted to protect the cladding tube against stress corrosion cracking, wherein the second zirconium based alloy comprises tin as an alloying material, and wherein each one of the zirconium based alloys comprises at least 96 percent by weight zirconium, wherein the main alloying materials of the first zirconium based alloy are niobium, iron and tin with the content of any additional substances being below 0.05 percent by weight, wherein the first zirconium based alloy comprises oxygen; the first zirconium based alloy comprising 0.6-1.2 percent by weight niobium, 0.6-1.2 percent by weight tin, and 0.1-0.3 percent by weight iron; wherein the main alloying materials of the second zirconium based alloy are tin and iron and wherein the content of any additional substances is below 0.05 percent by weight, and wherein the second zirconium based alloy comprises 0.1-1 percent by weight tin and 0.02-0.3 percent by weight iron; and wherein the thickness of the inner layer is 5-40% of the thickness of the reactor fuel cladding tube.