CN107976486B - Split pin probe assembly of nuclear power station control rod guide cylinder - Google Patents

Abstract

The invention discloses a split pin probe assembly of a control rod guide cylinder of a nuclear power station, which comprises a probe wafer, a wafer fixing frame for fixing the probe wafer, a bottom plate and a first buffer assembly connected between the bottom plate and the wafer fixing frame, wherein a second buffer assembly is also arranged between the first buffer assembly and the wafer fixing frame and comprises a middle plate connected with the first buffer assembly, a cylinder body sleeved on the middle plate and an elastic rubber ring fixed in the cylinder body, the wafer fixing frame is fixedly inserted in the elastic rubber ring and has a gap with the middle plate, the height of the probe wafer and the wafer fixing frame higher than the second buffer assembly is larger than the distance from the deepest part of a split pin groove to the lower end face of a grid plate, and the distance is a compression distance. The invention can self-adapt to positioning error and mounting error, and the contact pressure of the ultrasonic probe and the opening pin is constant, thereby being beneficial to the repeatability of ultrasonic inspection.

Description

Nuclear power plant control rod guide cylinder split pin probe assembly

technical field

The invention relates to the field of nuclear power detection, in particular to a split pin probe assembly for a control rod guide cylinder of a nuclear power plant.

Background technique

The cotter pin of the control rod guide cylinder is located in the upper inner member of the nuclear power plant reactor. Its function is to provide positioning and lateral support for the control rod guide cylinder, and it is an important factor for the control rod to fall as required during power regulation and emergency shutdown of the nuclear power plant. . The failure of cotter pins has occurred many times in foreign nuclear power plants. The consequences are reflected in two aspects. One is that the control rod guide cylinder is dislocated, which affects the falling time of the control rod. , will damage other important equipment and affect the integrity of nuclear power equipment. Therefore, it is necessary to carry out in-service inspection on the cotter pin of the control rod guide cylinder to monitor the quality status during its operation and improve the reliability, safety and integrity of the nuclear power plant.

In-service inspections are generally carried out during the overhaul of nuclear power plants. During major repairs, the entire upper internals assembly is stored in the structural pool. In order to carry out the ultrasonic inspection of the key area of the cotter pin, a flat probe needs to be inserted into the groove of the cotter pin. The width of the groove in the installed state is between 2.696mm and 2.896mm. However, limited by the size of the probe wafer, the width of the probe assembly is 2.4 mm. About mm, the underwater positioning accuracy is required to be high. Moreover, the end of the cotter pin is recessed into the bottom surface of the upper grid plate by 37.75 mm, which brings great difficulty to the observation and positioning of the end face of the cotter pin. In addition, after more than 20 years of operation of the nuclear power unit, the deformation of parts and assembly tolerances may cause the cotter pin to be deflected to a certain extent, so the probe assembly needs to have a certain flexibility to adapt to the situation; in addition, due to the ultrasonic probe and cotter pin A constant contact pressure is beneficial to the repeatability of ultrasonic inspection. In order to provide such a constant pressure, a pressure detection and adjustment mechanism is often required. It is extremely difficult to set the above structure on a probe assembly with a small size.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a nuclear power plant control rod guide cylinder cotter pin probe assembly which can be adaptive and can provide constant contact pressure to ensure the repeatability of detection.

In order to solve the above technical problems, the present invention adopts the following technical solutions: a nuclear power plant control rod guide cylinder split pin probe assembly, which includes a probe wafer, a wafer holder for fixing the probe wafer, a bottom plate, and a A first buffer component between the wafer holders, a second buffer component is further arranged between the first buffer component and the wafer holder, and the second buffer component includes a buffer component corresponding to the first buffer component. A connected middle plate, a cylindrical body sleeved on the middle plate, and an elastic rubber ring fixed inside the cylindrical body, the wafer holder is fixedly inserted in the elastic rubber ring and is connected with the middle plate There is a gap therebetween, and the height of the probe wafer and the wafer holder above the second buffer assembly is greater than the distance from the deepest part of the split pin groove to the lower end surface of the upper grid plate, which is the compression distance.

Preferably, the probe assembly further includes a cover plate which is covered on the cylinder and sleeved on the wafer holder.

Preferably, the lower end surface of the middle plate has an extension column extending downward and an annular plate extending radially outward from the lower end of the extension column, and the first buffer component includes a plurality of The annular plate and the guide columns in the bottom plate, and the support springs sleeved on each of the guide columns and located between the annular plate and the bottom plate, the two ends of the guide columns are provided with preventing them from sliding from the annular plate. and the nut that came off the base plate.

Preferably, the lower end of the wafer holder has a card plate extending radially outward, a through hole is formed in the middle of the elastic rubber ring, and the inner wall of the through hole is provided with a card matching the fixing ring. slot, the card board is clamped in the slot.

Preferably, the compression distance is 1-5 mm.

Further, the card board is in the shape of a racetrack, and has two parallel straight sides and an arc-shaped side connected between the two straight sides.

The beneficial effects of the invention are: the invention can adapt to the positioning error and the installation error of the internal components of the stack, and the contact pressure between the probe wafer and the cotter pin is constant, which is beneficial to the repeatability of ultrasonic inspection.

Description of drawings

Figure 1: Stereoscopic view of the probe assembly;

Figure 2: Sectional view of the probe assembly;

Figure 3: Sectional view of the probe assembly;

Figure 4: After the probe assembly is in contact with the groove of the cotter pin, the distance between the probe assembly cover and the bottom surface of the upper grid plate is 3mm.

Detailed ways

The present invention is described in detail below in conjunction with the embodiments shown in the accompanying drawings:

As shown in Figures 1, 2 and 3, the nuclear power plant control rod guide cylinder split pin probe assembly includes a probe wafer 71, a wafer holder 72 for fixing the probe wafer 71, a base plate 78, a base plate 78 connected to the base plate 78 and the A first buffer component between the wafer holders 72 and a second buffer component disposed between the first buffer component and the wafer holder 72 .

The second buffer assembly includes a middle plate 75 connected to the first buffer assembly, a cylinder 74 sleeved on the middle plate 75, an elastic rubber ring 79 fixed inside the cylinder 74, and a seal. A cover plate 73 covering the cylindrical body 74 and sleeved on the wafer holder 72 , the wafer holder 72 is fixedly inserted in the elastic rubber ring 79 and exists between the middle plate 75 The height of the probe wafer 71 and the wafer holder 72 above the second buffer assembly is greater than the distance from the deepest part of the groove of the split pin 721 to the lower end surface of the upper grid plate 722, which is the compression distance, so The compression distance is 1 to 5mm. The lower end of the wafer holder 72 has a clamping plate 716 extending radially outward, a through hole is formed in the middle of the elastic rubber ring 79 , and the inner wall of the through hole is provided with a matching plate 716 . A card slot, the card board 716 is clamped in the card slot. The card board is in the shape of a racetrack, and has two parallel straight sides and an arc-shaped side connected between the two straight sides. When the probe wafer 71 needs to be rotated adaptively, the elastic rubber ring 79 rotates and deforms with the wafer holder 72 and resets after the detection is completed.

The lower end surface of the middle plate 75 has an extension column 714 extending downward and an annular plate 715 extending outward along the radial direction of the extension column 714 from the lower end of the extension column 714 . The annular plate 715 and the guide column 76 in the bottom plate 78, the support spring 77 sleeved on each of the guide columns 76 and located between the annular plate 715 and the bottom plate 78, the guide column Both ends of 76 are provided with nuts 717 to prevent them from falling off from the annular plate 715 and the bottom plate 78 .

As shown in Figure 4, when the top of the probe assembly contacts the end face of the split pin 721, if there is a certain positioning deviation or installation error, the probe assembly can be automatically adjusted by the elastic rubber ring 79 and the supporting spring 77. After reaching the top of the groove of the cotter pin 721, the vertical lifting mechanism that drives the probe to move up and down (mechanisms such as air cylinders can be realized, which are not the focus of the present invention, and will not be repeated here) continues to rise until the cover plate 73 is in contact with the upper grid plate 722. , the support spring 77 and the elastic rubber ring 79 begin to compress. At this time, the contact pressure between the probe assembly and the split pin 721 is the elastic force that the support spring 77 and the elastic rubber ring 79 generate a total deformation of 1-5 mm, and remains unchanged. In this embodiment, the elastic coefficient of the rubber is 10N/mm, By adjusting the glue content and hardness, the best pressure on the probe is 30N, so the best deformation is 3mm. The probe assembly has certain flexibility, self-adaptive positioning error and installation error, and the contact pressure between the ultrasonic probe and the cotter pin 721 can be kept constant within the required range without additional pressure detection equipment, which is beneficial to the repeatability of ultrasonic inspection.

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (5)

1. The utility model provides a nuclear power station control rod guide cylinder split pin probe subassembly, its includes probe wafer, is used for fixing the wafer mount of probe wafer, bottom plate and connect in the bottom plate with the first buffer subassembly between the wafer mount which characterized in that: the probe comprises a first buffering assembly, a wafer fixing frame and a second buffering assembly, wherein the first buffering assembly is arranged on the wafer fixing frame, the second buffering assembly is arranged between the first buffering assembly and the wafer fixing frame, the second buffering assembly comprises a middle plate connected with the first buffering assembly, a cylinder body sleeved on the middle plate and an elastic rubber ring fixed inside the cylinder body, the wafer fixing frame is fixedly inserted into the elastic rubber ring and a gap exists between the middle plates, the height of the probe wafer and the wafer fixing frame is larger than the distance between the deepest part of a groove of a split pin and the lower end face of an upper grid plate, the distance is a compression distance, and the compression distance is 1-5 mm.

2. The nuclear power plant control rod guide cylinder cotter pin probe assembly as recited in claim 1, wherein: the probe assembly further comprises a cover plate which is covered on the cylinder body and sleeved on the wafer fixing frame.

3. The nuclear power plant control rod guide cylinder cotter pin probe assembly as recited in claim 1, wherein: the terminal surface has downwardly extending's extension post and by the annular plate that extends the radial outside extension of post under the post along extending, first buffering subassembly includes a plurality of wearing to locate simultaneously the annular plate with guide post, cover in the bottom plate are located every on the guide post and be located the annular plate with supporting spring between the bottom plate, the guide post both ends are equipped with the nut that prevents it from droing on annular plate and the bottom plate.

4. The nuclear power plant control rod guide cylinder cotter pin probe assembly as recited in claim 1, wherein: the lower end part of the wafer fixing frame is provided with a clamping plate which extends outwards along the radial direction, the middle part of the elastic rubber ring is provided with a through hole, the inner wall of the through hole is provided with a clamping groove matched with the clamping plate, and the clamping plate is clamped in the clamping groove.

5. The nuclear power plant control rod guide cylinder cotter pin probe assembly as recited in claim 4, wherein: the clamping plate is in a runway shape and is provided with two parallel straight edges and an arc-shaped edge connected between the two straight edges.

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