CN210795530U

CN210795530U - Mechanical centering device for hoisting top cover of pressure vessel of pressurized water reactor unit

Info

Publication number: CN210795530U
Application number: CN201921238572.8U
Authority: CN
Inventors: 聂文哲
Original assignee: CNNC Nuclear Power Operation Management Co Ltd; Qinshan Nuclear Power Co Ltd
Current assignee: CNNC Nuclear Power Operation Management Co Ltd; Qinshan Nuclear Power Co Ltd
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2020-06-19
Anticipated expiration: 2029-08-02

Abstract

The utility model relates to a nuclear power station machinery overhauls the field, concretely relates to a mechanical centering device for hoist and mount of pressurized water reactor unit pressure vessel top cap. The device comprises: the lug, the supporting head, the barrel, the cone, the target, the guide post, the top cap flange. The center of the upper part of the supporting head is provided with a circular disc, the lower part of the supporting head is a hollow cylinder, and the lifting lug is fixedly connected with the upper part of the supporting head through a bolt; the lower part of the supporting head is fixedly connected with the upper end of the cylinder body through threads, and the lower end of the cylinder body is fixedly connected with the cone; the target is mounted on a guide post. The utility model discloses excellent in use effect has shortened top cap repacking centering time effectively, produces economic benefits and has improved the unit security.

Description

Mechanical centering device for hoisting top cover of pressure vessel of pressurized water reactor unit

Technical Field

The utility model relates to a nuclear power station machinery overhauls the field, concretely relates to a mechanical centering device for hoist and mount of pressurized water reactor unit pressure vessel top cap.

Background

The reactor pressure vessel is used for fixing and containing a core and internals, so that the nuclear fuel fission reaction is limited to be carried out in a sealed metal shell. During the period of the pressurized water reactor unit refueling overhaul, the reactor top cover needs to be lifted from the reactor core to the top cover storage room so as to carry out nuclear fuel replacement. After the fuel is replaced, the top cover is lifted to the reactor core for reloading.

At present, when the top cover of the pressurized water reactor unit is installed again, the guide column installed on the bottom hole of the pressure container is used as a centering reference, and the pressurized water reactor unit is centered visually through a through hole of a flange of the top cover. Due to observation angle limitation, the centering mode needs to arrange personnel to perform auxiliary centering at the bottom of the refueling water pool, and at the moment, the reactor core is exposed and has extremely high radioactivity. Meanwhile, due to the limitation of a visual mode, the centering operation consumes long time, and the hoisting operation risk is high.

Taking the M310 reactor type as an example, the hoisting master command sends an instruction to a ring crane driver through an interphone, and the top cover is hoisted to the upper part of the reactor core from the top cover storage room. When the top cover is aligned with the guide post, the gap between the guide post and the through hole of the top cover needs to be observed for many times, and the position of the ring crane needs to be adjusted. Because the positions of the three guide columns need to be accurately centered, the hoisting command needs to be repeatedly observed to determine the position of the circular crane, and the centering time is long. Simultaneously because the top cap flange is thicker, personnel stand and can't see the guide post and get into the top cap through-hole above the pond, need arrange the staff at the bottom of the pool and observe, personnel expose the reactor core and have certain safety risk under the high radioactive environment this moment. According to experience feedback, other power plants have an event similar to guide post scratching at present, and certain influence is caused on equipment safety and major overhaul lines.

Disclosure of Invention

Firstly, the purpose is as follows: the mechanical structure auxiliary centering device for hoisting the top cover of the pressure vessel of the nuclear power pressurized water reactor unit can reduce the operation difficulty of the hoisting operation of the top cover of the pressure vessel, save a large amount of centering time, reduce the dosage of personnel, increase the visibility and the accuracy of the centering operation and ensure the safety of equipment. Has important significance for the safety and the economic benefit of the nuclear power plant.

The technical scheme is as follows:

a mechanical centering device for hoisting a top cover of a pressure vessel of a pressurized water reactor unit comprises: the lug, the supporting head, the barrel, the target. The center of the upper part of the supporting head is provided with a circular disc, the lower part of the supporting head is a hollow cylinder, and the lifting lug is fixedly connected with the upper part of the supporting head through a bolt; the lower part of the supporting head is fixedly connected with the upper end of the cylinder body through threads, and the lower end of the cylinder body is fixedly connected with the cone; the target is mounted on a guide post.

The cylinder body is hollow, and the outer wall of the cylinder body is hollow.

The lower end of the cone is in an inverted cone shape.

The middle of the target is a conical groove, and the groove is embedded with the lower end of the cone.

Cylindrical through holes are uniformly distributed on the top cover flange.

The outer diameter of the hollow cylinder at the lower end of the supporting head is the same as the inner wall of the hollow part of the flange.

The guide posts are distributed on the annular screw hole of the pressure container according to a certain angle.

Thirdly, the effect is as follows:

the design method is successfully applied to the top cover reinstallation of Qinshan nuclear power Fangjiashan No. 1 and No. 2 units. Through the field use experience feedback, the device has good use effect, effectively shortens the top cover re-assembly centering time, generates economic benefit and improves the unit safety. The device has the following advantages:

the invention relates to a mechanical structure auxiliary centering tool, which has the following functional characteristics:

1. the method is used for the top cover reinstallation of the pressure vessel of the pressurized water reactor nuclear power station.

2. The mechanical structure design is simple and easy to operate.

3. And materials such as aluminum alloy, nylon and the like are adopted, so that the light weight design meets the strength requirement at the same time.

4. And in the target design, the centering reference moves downwards, and the equipment hoisting centering precision is improved.

5. Visual blind areas are eliminated, a water tank is omitted for centering observers, and the safety of hoisting operation is improved.

Drawings

FIG. 1 is a schematic view of a mechanical centering device

FIG. 2 top view of the installation position of the mechanical centering device

In the figure: 1. lifting lug, 2, supporting head, 3, barrel, 4, cone, 5, target, 6, guide post, 7, top cover flange.

Detailed Description

A mechanical centering device for hoisting a top cover of a pressure vessel of a pressurized water reactor unit comprises: the lug, the supporting head, the barrel, the cone, the target, the guide post, the top cap flange. The device is matched with a top cover flange through hole through a supporting head so as to ensure the coaxiality of the center of the through hole and the cylinder body and cone.

As shown in fig. 1, the center of the upper part of the supporting head is provided with a circular disc, the lower part of the supporting head is a hollow cylinder, and the lifting lug is fixedly connected with the upper part of the supporting head through a bolt; the lower part of the supporting head is fixedly connected with the upper end of the cylinder body through threads, and the lower end of the cylinder body is fixedly connected with the cone; the target is mounted on a guide post.

The cylinder body is hollow, and the outer wall of the cylinder body is hollow.

The lower end of the cone is in an inverted cone shape.

Cylindrical through holes are uniformly distributed on the top cover flange.

As shown in fig. 2, the guide posts are distributed on the annular screw hole of the pressure vessel according to a certain angle.

The specific installation steps are as follows:

and (3) installing a mechanical centering device: one end of the long rope is connected with a lifting lug of the mechanical centering device. The maintainer steps on the top cap, inserts mechanical centering device into the top cap flange and corresponds the guide post through-hole to fix the other end of the long rope on the top cap hoist. And a target is installed in a screw hole in the upper part of the guide post.

Auxiliary centering for hoisting of the top cover of the pressure vessel: the top cap handling is to the reactor core top, and the relative position of cone and target can the direct observation to hoist and mount owner commander, finds the centering position through the adjustment. The top cover is slowly lowered until the cone contacts the target and ejects the cartridge from the through hole. And continuously descending the top cover to the position of the core.

Dismantling the mechanical centering device: the service person removes the device from the top cover using a long rope.

Claims

1. A mechanical centering device for hoisting a top cover of a pressure vessel of a pressurized water reactor unit comprises: the device comprises a lifting lug (1), a supporting head (2), a cylinder body (3) and a target (5); the method is characterized in that: a disc with a hole at the center of the upper part of the supporting head (2), and a hollow cylinder at the lower part of the supporting head are arranged on a top cover flange (7); the lifting lug (1) is fixedly connected with the upper part of the supporting head (2) through a bolt; the lower part of the supporting head (2) is fixedly connected with the upper end of the cylinder body (3) through threads, and the lower end of the cylinder body (3) is fixedly connected with the cone (4); the target (5) is mounted on the guide post (6).

2. The apparatus of claim 1, wherein: the cylinder body (3) is hollow, and the outer wall of the cylinder body is hollow.

3. The apparatus of claim 1, wherein: the lower end of the cone (4) is in an inverted cone shape.

4. The apparatus of claim 1, wherein: the middle of the target (5) is a conical groove, and the groove is embedded with the lower end of the cone (4).

5. The apparatus of claim 1, wherein: the flanges (7) are uniformly distributed with cylindrical through holes.

6. The apparatus of claim 1, wherein: the outer diameter of the hollow cylinder at the lower end of the supporting head (2) is the same as the inner wall of the hollow part of the flange (7).

7. The apparatus of claim 1, wherein: the guide posts (6) are arranged on screw holes which are distributed in the pressure container in an annular mode according to a certain angle.