PURPOSE: To detect the presence of a defect of a ZrO2 film in a non destructive manner, by a method wherein the ZrO2 film is formed on an inner surface of a Zr(alloy) pipe, a Cu layer is further formed on the ZrO2 film, and an electric resistance between the Ar(alloy) pipe and the Cu layer is measured.
CONSTITUTION: In an overheating steam with a temperature of about 400°C, an autoclave processing is conducted on an inner surface of a nuclear fuel sheathed pipe made of a Zr(alloy) to form a ZrO2 film 2 with a thickness of about 1μ. A Cu layer 3 is formed about 5μ thick on the layer 2 by a chemical plating method. In the composite type fuel sheathed pipe 1, the layer (3) surface acts as an electrode 4, and other electrode 6 is connected to a part 5, a where the ZrO2 film 2 is removed and has a metallic luster, at one end of the pipe 1 covered with the film 2 to measure (7) a resistance between the two electrodes 4 and 6. If a resistance value exceeds 106Ωcm, it is assured that the sheathed pipe 1 has a high reliability such that there is no defect in the layer 2, and the Cu layer 3 is in no danger of the production of Zr(alloy) and bristle alloy.
SHINPO KATSUTOSHI
KOZONOE ATSUSHI
