Zirconium alloy compositions having excellent corrosion resistance by the control of various metal-oxide and precipitate and preparation method thereof

Abstract

Disclosed herein are a zirconium alloy composition, which exhibits excellent corrosion resistance by varying the kinds of metal oxides and controlling the size of precipitates of the composition, including: 1.05˜1.45 wt % of Nb; one or more selected from the group consisting of 0.1˜0.7 wt % of Fe and 0.05˜0.6 wt % of Cr; and residual Zr, and a method of preparing the same. The zirconium alloy composition exhibits excellent corrosion resistance by controlling the kinds and amounts of the elements included in the zirconium alloy composition and the heat-treatment temperature and thus varying the kinds of metal oxides formed during an oxidation process and controlling the size of precipitates of the zirconium alloy, so that it can be usefully used as a raw material for nuclear fuel cladding tubes, spacer grids, nuclear reactor internals and the like of a light-water reactor or a heavy-water reactor in a nuclear power plant.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a zirconium alloy composition having excellent corrosion resistance by the control of various metal oxides and precipitates of the composition, and a method of preparing the same.[0003]2. Description of the Related Art[0004]Nuclear fuel cladding tubes, spacer grids and nuclear reactor internals, which are used in a nuclear fuel assembly of a nuclear power plant, are easily embrittled and corroded due to the nuclear irradiation and the corrosive environment of high temperature and high pressure, and thus their mechanical properties are deteriorated. For this reason, it is important to control their alloy compositions. Therefore, zirconium alloys having small neutron absorption cross sections, high mechanical strength and excellent corrosion resistance have been widely used in a pressurized water reactor (PWR) and a boiling water reactor (BWR). Among conventional zirconium alloys including...

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Benefits of technology

[0020]In order to accomplish the above object, the present invention provides a zirconium alloy composition, which exhibits excellent corrosion resistance by the control of various metal oxides and precipitates of the composition, comprising 1.05˜1.45 wt % of Nb; at least one of 0.1˜0.7 wt % of Fe and 0.05˜0.6 wt % of Cr; 0.12 wt % of Sn; and residual Zr, and a method of preparing the same.

[0021]Since the zirconium alloy composition according to the present invention exhibits excellent corrosion resistance by controlling the kinds and amounts of the elements included in the zirconium alloy composition and the heat-treatment temperature and thus varying the kinds of metal oxides formed during an oxidation process and controlling the size of precipitates of the zirconium alloy, it can be usefully used as a raw material of nuclear fuel cladding tubes, spacer grids, nuclear reactor internals and the like of a light-water reactor or a heavy-water reactor in a nuclear power plant.

Problems solved by technology

Nuclear fuel cladding tubes, spacer grids and nuclear reactor internals, which are used in a nuclear fuel assembly of a nuclear power plant, are easily embrittled and corroded due to the nuclear irradiation and the corrosive environment of high temperature and high pressure, and thus their mechanical properties are deteriorated.

Therefore, when the conventional Zircaloy-2 or Zircaloy-4 is used as a raw material for a nuclear fuel cladding tube, there is a problem in that the corrosion phenomenon of the nuclear fuel becomes serious.

That is, since carbon atoms interposed between iron atoms serve to prevent the movement of iron atoms, as the amount of carbon included in iron is increased, the hardness of iron increases, whereas as the hardness of iron increases, iron is easily broken.

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