Chromalizing device and process for small hole of driving device for control rod of nuclear reactor

Abstract

The invention provides a chromalizing device for a small hole of a driving device for a control rod of a nuclear reactor. The chromalizing device comprises an anode and auxiliary cathodes, wherein the auxiliary cathodes are shaped like sheets and arranged by covering the two ends of the small hole; the anode is of a cylindrical body arranged along the axial direction of the small hole and penetrates through the end surfaces of the auxiliary cathodes, and radial gaps are arranged between the anode and the auxiliary cathodes; and anode insulation sleeves are sheathed at the parts at the two ends of the anode, which are exposed on the outer side of the small hole. A preparation process sequentially comprises the following steps of: (1) performing alkaline cleaning to remove oil and cleaning with B-grade pure water; (2) assembling the chromalizing device; and (3) using an electroplating solution which only comprises CrO3, concentrated H2SO4 and Cr<3+> components to chromalize the small hole. The thickness of a plated layer prepared by adopting the method is at least not less than 45mu m; the deviation of the axle center of the plated layer after plating does not exceed 10mu m; and the plated layer has no micro-cracks and can meet the using requirements of working conditions and ensure the effective operation of the driving device for the nuclear control rod.

Description

technical field [0001] The invention relates to the field of surface treatment, in particular to a chrome-plating device and a process for small holes of a nuclear reactor control rod driving device. Background technique [0002] In the nuclear control rod driving device, many parts contain small holes and the sizes of the small holes are different, such as φ9.54mm, φ12mm, φ61.35mm, φ65.41mm, but each small hole needs to be chrome-plated and the plating requirements are the same: namely The thickness of the coating shall be at least 45 μm; the axial center of the coating shall not deviate more than 10 μm in the radial direction after plating; the coating shall have no microcracks. However, the radius of such small holes is small, especially the radius of the φ9.54mm small hole is not more than 5mm, and the distance between the cathode and the anode is very close during the plating process. Fast, very easy to initiate cracks. [0003] Therefore, in order to control the grow...

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Problems solved by technology

However, the radius of such small holes is small, especially the radius of the φ9.54mm small hole is not more than 5mm, and the distance between the cathode and the anode is very close during the plating process. Fast, very easy to initiate cracks

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