Tool and method for repairing omega seal weld defects of CRDM (control rod drive mechanism) pressure-resistant housing of nuclear power plant

Abstract

The invention discloses a tool and a method for repairing the omega seal weld defects of the CRDM (control rod drive mechanism) pressure-resistant housing of a nuclear power plant. The tool comprises a knife body, roller wheels, a knife rest and a knife, wherein a perforated hole used for sleeving a CRDM pressure-resistant housing omega seal weld seam is formed in the knife body; the roller wheels are mounted on the knife body, and the edges of the roller wheels protrude out of the edges of the perforated hole of the knife body to guide the rotation of the knife body; the knife is fixed to the knife body through the knife rest and extends out of the perforated hole to be in close contact with the weld defects. The method comprises the following steps: removing the defects by the repair tool and performing quick and high-quality repair welding on the weld seam by an automatic fusion ring pulsed tungsten argon arc welding process. Compared with the prior art, the tool and the method have the characteristics that the weld defects can be quickly removed, a specific repair groove is formed, and the knife can be effectively guaranteed to be accurately positioned during defect removal.

Description

technical field [0001] The invention belongs to the field of construction and installation of nuclear power plants. More specifically, the invention relates to a tool and method for repairing welding defects of CRDM pressure shell Ω of nuclear power plants. Background technique [0002] The Control Rod Drive Mechanism (CRDM for short) is an extremely important servo mechanism in the reactor control and protection system of a nuclear power plant, which is used to realize safety functions such as reactor startup, power increase, power maintenance, load tracking, normal shutdown and emergency shutdown; The pressure vessel at the lower part of the CRDM is the pressure boundary of the primary circuit of the nuclear power plant. CRDM is installed above the pressure vessel connecting seat, and its pressure shell and pressure vessel connecting seat are connected by Ω-tight welding. During the construction and operation of nuclear power plants, there are repairs of CRDM pressure she...

AI Technical Summary

Problems solved by technology

However, this solution has at least the following deficiencies: First, it is difficult to control the opening position when the ordinary drill bit is used to remove welding defects, which makes it difficult to remove the defects, and may damage the base material around the weld, and the construction efficiency is relatively low; second, When the manual TIG welding process repairs defects, the welding quality is greatly affected by human factors, not only the construction efficiency is low, the quality of the weld is difficult to guarantee, but also the radiation dose received by the construction personnel during operation is relatively large

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