Rapid clamping mechanism for nuclear reactor cable

Abstract

The invention belongs to the technical field of nuclear reactor maintenance tools for nuclear power stations, and particularly relates to a quick clamping mechanism for a nuclear reactor cable. The first cylindrical pin fixes the semicircle of the clamping buckle, the second cylindrical pin is installed on the clamping buckle and used for fixing the pawl buckle, the switch head drives the cam to drive the pawl and the pawl buckle to be opened and closed, the spring is used for fixing the pawl buckle to prevent the pawl buckle from falling off, the third cylindrical pin is used for fixing the clamping shell, the pawl is arranged on the inner side of the clamping shell, and the switch head is arranged on the upper side of the clamping shell. All the components are mounted on the base. The problem of rapid clamping in the nuclear reactor cable dismounting and mounting process is solved, and the problem of field operation limitation proposed in the background technology is gradually improved and finally solved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power plant nuclear reactor maintenance tools, and in particular relates to a nuclear reactor cable quick clamping mechanism. Background Art

[0002] The reactor side equipment of the nuclear reactor control and protection system of the No. 1-4 VVER units of Tianwan Nuclear Power Plant is numerous, mainly including: 54 core nuclear measurement loop cables on the cement wall side of the core reactor shaft; 54 neutron temperature measurement channels; 103 rod control rod position instrumentation cables on the cement wall side of the core reactor shaft; 103 rod control rod position power cables on the cement wall side of the core reactor shaft;

[0003] The core nuclear measurement loop cable and the neutron temperature measurement channel equipment are both Class 1E important safety equipment. There are 163 fuel assemblies in the core, of which 54 fuel assemblies are equipped with neutron temperature measurement channels, and each neutron temperature measurement channel occupies the position of a fuel rod. The core neutron temperature measurement channel consists of three parts: a protective sleeve, a core measurement probe, and an electrical connection plug. Among them, the measurement probe includes 7 self-powered neutron detectors (SPND), a nickel-chromium-nickel-aluminum "K" type thermocouple thermometer (TT), and a thermal resistance thermometer (RT). After the neutron temperature measurement channel is connected to the core nuclear measurement loop cable, it outputs the reactor core monitoring parameters, including neutron flux density, reactor coolant temperature, reactor pressure vessel liquid level, etc.

[0004] During routine operation, real-time monitoring of the reactor core neutron flux density is achieved. When the reactor power is in the range of (30-110)% Norm, core emergency protection signals are generated based on local core parameters (linear power density QL of fuel elements and deviation from nucleate boiling ratio DNBR), and these signals are sent to the safety instrumentation and control system TXS to realize the reactor protection function. During overhaul, the core nuclear measurement cables are disconnected and connected, and the neutron temperature measurement channels are pulled out and installed (overall replacement).

[0005] After the rod control position cable is connected to the upper side of the control rod drive mechanism on the reactor side, the upper end of each bundle of control rods is fixedly connected to the SHEM-3 of the drive mechanism, and moves up and down in the core or remains at any height in the core with the drive shaft of SHEM-3, thereby realizing the control of reactor power. The main functions realized by the system are as follows: reactor reactivity and power control; transfer the reactor core to subcriticality and maintain it in this state; complete the control function and maintain the reactor power in "automatic" mode, and realize control from APC; reduce power and shut down the reactor; display the control rod group position in the main control room and the standby control room; display the control rod single rod position on the PIV monitor; display the operation status (operation / fault) of the rod control position system equipment in the main control room; generate other information and send it to other instrumentation and control subsystems.

[0006] Due to the need for overhaul equipment maintenance, the local equipment of the system is mainly used for insulation inspection, plug cleaning and performance inspection after the removal of rod control rod position instrumentation and power cables during the overhaul of the unit. The CPS system is mainly responsible for controlling the up and down movement of 103 control rods within the core height, monitoring the position of the control rods at the core height, and realizing the power control of the reactor. During the overhaul, the 103 pairs of control rod position top cable assemblies need to be removed and installed. During the removal and reinstallation of the cable assembly, the cable interface on the core cement wall and the control rod drive mechanism needs to be sealed and removed with a plug. Since the working area is a first-level foreign body protection area, it is very easy to cause the risk of foreign body falling; if the installation quality of the reinstalled cable assembly is not high, it will cause the risk of control rods losing control or accidentally falling during the operation of the unit, seriously affecting the safe and stable operation of the unit and causing huge economic losses. Due to the particularity of the workplace, there are unfavorable factors such as long time occupying the main line of the overhaul, complex procedures, large workload, high temperature, radiation, and industrial safety risks. In order to ensure the normal operation of the equipment, reliable cable reinstallation tools are needed to reduce the problem of poor work quality caused by human factors; it is necessary to avoid rework caused by large workload and complex procedures; it is necessary to innovate tool application and optimize process flow to achieve time-saving and labor-saving work results.

[0007] During the unit refueling overhaul (long cycle 18 months refueling), the nuclear reactor cables are currently required to be inspected and maintained by manpower, mainly including the disassembly and assembly of the threaded end joints of the instrumentation and control cables on the cement wall side of the reactor shaft and the disassembly and assembly of the threaded end joints of the instrumentation and control cables on the control rod drive mechanism side. Cable maintenance needs to be carried out for a long time in difficult environments such as high temperature, high radiation dose, and narrow working space. Manual operation is difficult and time-consuming, and there are urgent practical problems such as work efficiency needs to be improved and the risk of heat stroke.

[0008] The current human-powered nuclear reactor cable maintenance (dismantling and installation) process has the following major problems: a large number of cables, narrow cable spacing, and difficult manual operation; high radiation doses, a limited number of cables that can be inspected by a single person, and a long overall working time; high working environment temperatures, requiring multiple rotations of personnel to complete the overall work, and the risk of heat stroke.

[0009] Due to the high working environment temperature, high radiation dose, narrow working space, and large number of working objects of nuclear power plant nuclear reactors, manual operation is required to realize the removal and installation of the self-contained cable end joints and the joints on the reactor cement wall side and the control rod drive module side, which is inefficient and not conducive to the health of the workers. Therefore, it is of great significance to develop a nuclear reactor cable quick clamping mechanism according to the maintenance needs of nuclear power plant reactors, improve the maintenance efficiency of nuclear reactor control and protection systems, shorten the working time of overhaul critical paths, reduce the risk of heat stroke, and reduce the man-hours and collective doses consumed. Summary of the invention

[0010] The purpose of the present invention is to provide a nuclear reactor cable quick clamping mechanism to achieve the quick clamping problem during the disassembly and assembly of the nuclear reactor cable, gradually improve and ultimately solve the on-site operation limitation problem raised in the above background technology.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] A nuclear reactor cable quick clamping mechanism, cylindrical pin one fixes the clamping buckle semicircle, cylindrical pin two is installed on the clamping buckle to fix the ratchet buckle, the switch head drives the cam to drive the ratchet and the ratchet buckle to open and close, the spring is used to fix the ratchet buckle to prevent it from falling off, cylindrical pin three is used to fix the clamping shell, the inner side of the clamping shell is the ratchet, and the upper side is the switch head, and the above components are all installed on a base.

[0013] The clamping buckle is rotated around the cylindrical pin 1 to open so as to facilitate the insertion of the nuclear reactor cable connector, and the ratchet buckle is rotated around the cylindrical pin 2. When it is rotated to be parallel to the length direction of the base, the clamping action can be performed.

[0014] The switch head drives the cam to drive the opening and closing of the pawl and the pawl buckle. When the cam rotates to the minimum diameter and contacts the pawl, the pawl buckle is inserted into a fixed position, and the spring supports the pawl buckle to prevent it from detaching. At this time, the cable head is in a clamped state; when the cam rotates to the maximum diameter and contacts the pawl, the pawl buckle can be easily pulled out, which means the locking state is released.

[0015] The clamping buckle opens, and the rotating clamping buckle rotates around the cylindrical pin while pressing the cable connector. The ratchet buckle is inserted into the clamping housing. The cam is in a clamping state through the rotation of the switch head. The spring presses the ratchet buckle so that the ratchet buckle cannot retreat, and the clamping buckle is pressed tightly.

[0016] The cam is in a released state through the rotation of the switch head, and the cam pushes the pawl to rotate backward, so that the pawl buckle is out of contact with the pawl, and the cable connector can be removed by rotating the clamping buckle open.

[0017] The beneficial effects achieved by the present invention are:

[0018] The present invention solves the function of fixing and clamping the cable head during assembly and disassembly; the present invention solves the function of positioning the cable head during assembly and disassembly; the present invention enables the tool and the cable head to be quickly assembled and disassembled, thereby improving work efficiency; the present invention adopts a ratchet method for locking, which has the advantage of small size compared with the existing bolt locking and cam mechanism locking; the present invention adopts a ratchet method for locking, which has a smaller operating space than the existing bolt locking and cam mechanism locking; the present invention adopts a ratchet method for locking, which has high work efficiency compared with the existing bolt locking and cam mechanism locking, and is plug-and-play without waiting during installation, and can be disengaged by simply rotating the camshaft to push open the ratchet claw during disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the released state of the cable quick clamping mechanism of the present invention.

[0020] Figure 2 It is a schematic diagram of the locking components of the cable quick clamping mechanism of the present invention.

[0021] Figure 3 This is a schematic diagram of the cable head installation state of the cable quick clamping mechanism of the present invention.

[0022] Figure 4 This is a schematic diagram of the cable quick clamping mechanism of the present invention clamping a cable head.

[0023] Figure 5 1 is an exploded view of some parts of the cable quick clamping mechanism of the present invention.

[0024] Figure 6 This is an exploded view II of some parts of the cable quick clamping mechanism of the present invention.

[0025] Figure 7 FIG. 3 is an exploded view of some parts of the cable quick clamping mechanism of the present invention.

[0026] Figure 8 This is a cross-sectional view of the cable quick clamping mechanism of the present invention.

[0027] In the figure: cylindrical pin one 1, clamping buckle 2, cylindrical pin two 3, pawl buckle 4, switch head 5, cam 6, cylindrical pin three 7, pawl 8, spring 9, clamping shell 10, base 11. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The cylindrical pin 1 fixes the semicircle of the clamping buckle 2, and the cylindrical pin 2 3 is installed on the clamping buckle 2 to fix the pawl buckle 4. The switch head 5 drives the cam 6 to drive the pawl 8 and the pawl buckle 4 to open and close. The spring 9 is used to fix the pawl buckle 4 and prevent it from falling off. The cylindrical pin 3 7 is used to fix the clamping shell 10. The inner side of the clamping shell 10 is the pawl 8, and the upper side is the switch head 5. The above components are all installed on the base 11.

[0030] The nuclear reactor cable connector is placed vertically downward into the recess of the cable disassembly and assembly tool to be clamped, wherein the clamping buckle 2 is rotated around the cylindrical pin 1 to open and facilitate the insertion of the nuclear reactor cable connector. The ratchet buckle 4 can rotate around the cylindrical pin 2 3, and when it is rotated to be parallel to the length direction of the base 11, the clamping action can be performed.

[0031] The locking function part of the mechanism, the switch head 5 drives the cam 6 to drive the pawl 8 and the pawl buckle 4 to open and close. When the cam 6 rotates to the minimum diameter and contacts the pawl 8, the pawl buckle 4 is inserted into the fixed position, and the spring 9 supports the pawl buckle 4 to prevent it from being disengaged. At this time, the cable head can be in a clamped state. When the cam 6 rotates to the maximum diameter and contacts the pawl 8, the pawl buckle 4 can be easily pulled out, that is, the locking state is released, and the tool can be used for the installation and disassembly of the next nuclear reactor cable head;

[0032] During installation, the clamping buckle 2 is opened, the cable connector is placed in the groove of the cable disassembly and assembly tool, the rotating clamping buckle 2 rotates around the cylindrical pin and presses the cable connector at the same time, the ratchet buckle 4 is inserted into the clamping housing 10, and the cam 6 is rotated through the switch head 5 to be in a clamping state. The spring 9 presses the ratchet buckle 8 so that the ratchet buckle 4 cannot retreat, and the clamping buckle 2 is pressed tightly.

[0033] To loosen the cable connector, the cam 6 is rotated in a loosened state through the switch head 5, and the cam 6 pushes the pawl 8 to rotate backward, so that the pawl buckle 4 is out of contact with the pawl 8, and the rotating clamping buckle 2 is rotated and opened to remove the cable connector.

[0034] The present invention belongs to a part of the automatic disassembly and assembly tool for cable maintenance of a nuclear reactor. When the automatic disassembly and assembly tool for cable maintenance performs the above-mentioned core side rod control rod position instrumentation and power cable installation work, the following operating steps need to be performed in sequence: confirm that the working state of the automatic disassembly and assembly tool for cable maintenance is in the locking installation mode; adjust the locking torque of the mechanical torque device to the working range value; pre-connect the cable connector and the base; insert the cable connector quick clamping mechanism through the opening of the automatic disassembly and assembly tool for cable maintenance, and fix the cable connector through the above-mentioned operating process; place the automatic disassembly and assembly tool for cable maintenance vertically, and calibrate it with a level bubble, press the throttle switch button, and the automatic tool drives the cable connector housing to rotate, and starts to lock after automatically screwing in. The cable removal process is similar to the installation process. When the disassembly tool is performing cable removal work, the following operations need to be confirmed in sequence: confirm that the working status switch of the cable disassembly tool is in the release mode; adjust the mechanical torque setting device to release the torque to the working range; place the cable connector into the connector quick clamping mechanism through the opening side of the cable disassembly automation tool, and fix the cable connector through the above operation process; place the cable automation disassembly tool vertically, and calibrate it with a spirit level, press the throttle switch button, the tool drives the cable connector shell to rotate, and automatically rotates out to start the release operation.

[0035] In summary, the invention of the cable connector quick clamping mechanism in the cable disassembly and assembly tool has achieved more reliable and rapid completion of the cable removal and installation of the reactor control and protection system, which can significantly improve the efficiency of cable removal and installation, reduce the working time of personnel in high temperature and high radiation environment, reduce the collective radiation dose of personnel, and ensure that personnel radiation activities meet the reasonable and feasible low ALARA principle. The tool is easy to operate and has the advantages of preventing foreign objects and not being easily deformed after collision. The use of the cable quick clamping mechanism on site is conducive to the optimization and improvement of the cable maintenance process, which can effectively reduce the main line overhaul time, and the on-site application will produce obvious social and economic benefits.

Claims

1. A nuclear reactor cable quick clamping mechanism, characterized in that: Cylindrical pin one fixes the semicircle of the clamping buckle, and cylindrical pin two is installed on the clamping buckle to fix the pawl buckle. The switch head drives the cam to drive the pawl and the pawl buckle to open and close. The spring is used to fix the pawl buckle and prevent it from falling off. Cylindrical pin three is used to fix the clamping shell. The inner side of the clamping shell is the pawl, and the upper side is the switch head. The above components are all installed on the base.

2. The nuclear reactor cable quick clamping mechanism according to claim 1, characterized in that: The clamping buckle is rotated around the cylindrical pin 1 to open so as to facilitate the insertion of the nuclear reactor cable connector, and the ratchet buckle is rotated around the cylindrical pin 2. When it is rotated to be parallel to the length direction of the base, the clamping action can be performed.

3. The nuclear reactor cable quick clamping mechanism according to claim 1, characterized in that: The switch head drives the cam to drive the opening and closing of the pawl and the pawl buckle. When the cam rotates to the minimum diameter and contacts the pawl, the pawl buckle is inserted into a fixed position, and the spring supports the pawl buckle to prevent it from detaching. At this time, the cable head is in a clamped state; when the cam rotates to the maximum diameter and contacts the pawl, the pawl buckle can be easily pulled out, which means the locking state is released.

4. The nuclear reactor cable quick clamping mechanism according to claim 1, characterized in that: The clamping buckle opens, and the rotating clamping buckle rotates around the cylindrical pin while pressing the cable connector. The ratchet buckle is inserted into the clamping housing. The cam is in a clamping state through the rotation of the switch head. The spring presses the ratchet buckle so that the ratchet buckle cannot retreat, and the clamping buckle is pressed tightly.

5. The nuclear reactor cable quick clamping mechanism according to claim 1, characterized in that: The cam is in a released state through the rotation of the switch head, and the cam pushes the pawl to rotate backward, so that the pawl buckle is out of contact with the pawl, and the cable connector can be removed by rotating the clamping buckle open.

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