Method of treating zirconium-based alloy tubes
AssigneeAB Asea-Atom
InventorGunnar Vesterlund
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Abstract
In the process of applying a layer of copper and a layer of zirconium dioxide to the internal surface of a tube of a zirconium-based alloy, with the layer of zirconium dioxide being located between the copper layer and the internal surface of the tube, the tube surface is first treated with an activating solution in the form of an aqueous solution containing from about 1 to about 3 grams/liter of hydrogen fluoride, from about 2 to about 8 grams/liter of ammonium fluoride and from about 0.1 to about 0.5 gram/liter of sulfuric acid, the amounts of hydrogen fluoride and ammonium fluoride being chosen so that the amount of ammonium fluoride, calculated in moles, exceeds the amount of hydrogen fluoride, calculated in moles, by at least 5 percent.
Claims14
A method of producing cladding tubes, said method comprising the steps of
- (a) providing a tube made of a zirconium-based alloy,
- (b) treating the internal surface of the tube of step (a) to form an oxide layer thereon having a thickness of between about 0.01 and about 0.1 micron,
- (c) contacting the oxide layer on the internal surface of the tube of step (b) with an activating solution, said activating solution consisting of an aqueous solution containing from about 1 to about 3 g/l of hydrogen fluoride, from about 2 to about 8 g/l of ammonium fluoride and from about 0.1 to about 0.5 g/l of sulfuric acid, the amount of ammonium fluoride, calculated in moles, exceeding the amount of hydrogen fluoride, calculated in moles, by at least 5 percent,
- (d) applying a copper layer to the treated oxide layer on the internal surface of the tube of step (c), and
- (e) treating the tube of step (d) to provide a layer of zirconium dioxide between the internal surface of the tube and the copper layer thereon.
A method of producing cladding tubes, said method comprising the steps of
- (a) providing a tube made of a zirconium-based alloy,
- (b) treating the internal surface of the tube of step (a) to form an oxide layer thereon having a thickness of between about 0.01 and about 0.1 micron,
- (c) contacting the oxide layer on the internal surface of the tube of step (b) with an activating solution, said activating solution consisting of an aqueous solution containing from about 1 to about 3 g/l of hydrogen fluoride, from about 2 to about 8/gl of ammonium fluoride and from about 0.1 to about 0.5 g/l of sulfuric acid, the amount of ammonium fluoride, calculated in moles, exceeding the amount of hydrogen fluoride, calculated in moles, by at least 5 percent,
- (d) applying a layer of zirconium dioxide to the treated oxide layer on the internal surface of the tube of step (c), and
- (e) treating the tube of step (d) to provide a layer of copper on the layer of zirconium dioxide.
Dependencies are inferred from the claim text.