Front-end probe mechanism of reactor pressure vessel checking machine

Abstract

The invention relates to a front-end probe mechanism of a reactor pressure vessel checking machine. The front-end probe mechanism comprises an ultrasonic probe body, a probe support framework framed outside the ultrasonic probe body, and a wall support frame in rotary connection with the probe support framework through a third rotating shaft; the probe support framework comprises an inner frame in rotary connection with two opposite sides of the ultrasonic probe body through a first rotating shaft respectively and an outer frame in rotary connection with two opposite sides of the inner frame through a second rotating shaft respectively; a torsion spring is also sleeved on the third rotating shaft; one end of the torsion spring is connected with the wall support frame, while the other end is connected with the outer frame; and the first rotating shaft, the second rotating shaft and the torsion spring provides a rotating freedom for the ultrasonic probe body on a spherical surface so that the ultrasonic probe body is tightly coupled with the spherical surface to be detected. The probe mechanism overcomes the defect of detection data loss due to poor coupling of the probe body and the spherical surface, and lays a foundation for safe operation of a nuclear power station.

Description

Technical field [0001] The invention relates to a welding seam detection equipment for a nuclear power plant reactor pressure vessel. Background technique [0002] The bottom of the nuclear reactor pressure vessel is welded by a cylindrical cylinder 100 and a hemispherical lower head 200, such as figure 1 As shown, therefore, there is a weld 300 at the joint between the two under the pressure vessel. According to the relevant inspection specifications of nuclear power plants, a 50mm area on both sides of the weld is required ( image 3 (Shown in the middle shaded part) for flaw detection. At the same time, the surfacing layer on the surface also needs to be scanned with the weld as the center line and 250mm on both sides. The existing technology has adopted the principle of ultrasonic detection. The principle of the inspection machine is to extend the probe into the bottom of the pressure vessel for scanning. Since the area to be scanned is a spherical surface, and the existing in...

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Problems solved by technology

[0002] The lower part of the nuclear reactor pressure vessel is welded by a cylindrical body 100 and a hemispherical lower head 200, such as figure 1 As shown, therefore, there is a weld 300 at the connection between the two under the pressure vessel. According to the relevant inspection specifications of nuclear power plants, the area of ​​50mm on both sides of the weld ( image 3 (shown in the shaded part in the middle) for flaw detection inspection. At the same time, the surfacing layer on the surface also needs to be scanned with the weld as the center line and 250 mm on both sides. In the prior art, there are ultrasonic principles for detection The principle of the inspection machine is to extend the probe into the bottom of the pressure vessel for scanning. Since the area to be scanned is a spherical surface, the installation method of the existing ultrasonic probe cannot ensure the close coupling between the probe and the spherical arc surface, resulting in unreliable detection results. Moreover, at the bottom of the pressure vessel, there are a plurality of penetrating pieces 400 erected on different horizontal levels, and the top penetrating piece 400 is close to the area to be tested, so that the movement range of the ultrasonic probe is blocked, thus affecting the comprehensive scanning of the area to be tested.

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