A device and method for mitigating remote installation of lagging pads

Abstract

The present application belongs to the technical field of nuclear power, and particularly relates to a device and method for relieving the remote installation of a heat insulation sleeve cushion. The device comprises a grabber and a screwing tool. The grabber is used to grab the cushion, bolts and locking caps, and to install and remove the cushion. The screwing tool is used to position and install the cushion on the upper cover plate of the control rod guide cylinder, and to fasten the bolts. The present application has the beneficial effect that the air cylinder is used to drive the opening and closing of the grabber, so that the cushion is clamped. At the same time, the built-in spring ensures that the grabber is in the open state when the air is lost, so that the cushion is prevented from falling. The bolts and locking caps are hoisted together with the cushion, and the grabber has the function of preventing falling, so that the clamping, transmission, positioning and screwing of the cushion are integrated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear power, and particularly relates to a device and method for remotely installing a spacer block for a spacer. BACKGROUND

[0002] The spacer belongs to a component of a control rod drive mechanism, is installed in a CRDM pipe seat on a top cover of a pressure vessel in a suspended manner, and is installed in a radial gap fit and an axial unconstrained manner. During operation of the unit, the spacer is affected by flow-induced vibration of a primary loop medium, which causes rubbing between an upper end of the spacer and a flange joint of the CRDM pipe seat, and causes the spacer height position to drop. With the increase of the operation time, the spacer end wear causes the spacer pipe position to drop intensively. If no intervention is made, the spacer pipe settlement distance will become larger and larger, and finally the whole spacer pipe will fall after the end part is worn out.

[0003] At present, a common mitigation measure is to install a mitigation block on a top cover plate of a control rod guide tube of an upper in-core component. The block is composed of a vertebral body and a flange, the flange has three groups of uniformly distributed bolts and locking caps, and the flange has two evenly distributed positioning holes. The positioning of the block relies on the cooperation of the positioning holes and the anti-rotation pins on the top cover plate of the guide tube, the fixation of the block relies on the fastening of the three groups of bolts, and the anti-loosening is achieved by the locking caps matched with the bolts.

[0004] Since the contact dose of the guide tube is about 15 mSv / h, boracic acid water needs to be used for shielding, and therefore the installation of the block on the end face of the guide tube needs to be performed underwater. The guide tube is immersed in boracic acid water (boracic acid water concentration 2400-2500 ppm), and an operator stands on an auxiliary bridge above the water pool to perform remote operation. SUMMARY

[0005] The purpose of the present application is to provide a device and method for remotely installing a spacer block for a spacer, which can integrate clamping, transmission, positioning and screwing, is used for underwater remote installation of the spacer block, and installs the spacer block on the end face of the control rod guide tube and fastens it firmly.

[0006] The technical scheme of the present application is as follows: a device for remotely installing a spacer block for a spacer, comprising a grabber and a screwing tool, the grabber is used to grab the block, bolts and locking caps, and install and remove the block, and the screwing tool is used to position and install the spacer block on the top cover plate of the control rod guide tube and fasten the bolts.

[0007] The grabber comprises a plug, a grab claw, a driving rod, a cylinder piston rod, a spring, a guide cup, a positioning pin and a disc, the plug is located in the center of the grabber, the upper end of the driving rod is connected with the cylinder piston rod, the lower end is in contact with the wedge surface of the grab claw, when the lower port of the cylinder is supplied with air, the cylinder piston rod drives the driving rod to move upward, drives the grab claw to close, and the grabber is separated from the cushion block; when the upper port of the cylinder is supplied with air, the cylinder piston rod drives the driving rod to move downward, drives the grab claw to open, clamps the inner tapered surface of the cushion block, and the grabber is fixed with the cushion block.

[0008] The spring in the compressed state is located between the cylinder and the driving rod, when the cylinder loses air, the compression force of the spring makes the driving rod be located at the lower position, and the grab claw keeps the open state, preventing the grabber from being separated from the cushion block.

[0009] The screwing tool comprises a long rod and an outer hexagonal screwing head, and the end of the long rod is connected with the outer hexagonal screwing head.

[0010] The guide cup has three uniformly arranged bolt positions.

[0011] The positioning pin is fixed on the disc of the grabber and is a tapered cylindrical pin, which is inserted into the positioning process hole on the flange of the cushion block to realize the positioning of the grabber and the cushion block.

[0012] The grab claw has three uniformly arranged pins on the plug, and the closing and opening are realized by swinging around the pin shaft.

[0013] A method for remotely installing a cushion block for a heat insulation sleeve comprises the following steps:

[0014] Step 1: before the cushion block is installed, the bolt and the locking cap are installed on the cushion block;

[0015] Step 2: the lower cylinder of the cylinder is supplied with air, the cylinder piston rod is in the upper position, and the three grab claws are closed;

[0016] Step 3: when the grabber clamps the cushion block, the plug is inserted into the central hole of the cushion block, and the positioning pin is inserted into the positioning process hole on the cushion block to realize the circumferential positioning;

[0017] Step 4: the disc of the grabber is tightly attached to the upper end surface of the cushion block;

[0018] Step 5: the upper cylinder of the cylinder is supplied with air, the cylinder piston rod is in the lower position, the three grab claws are opened, and the fixed clamping between the grabber and the cushion block is realized;

[0019] Step 6: the grabber together with the cushion block is transmitted to the upper side of the upper cover plate of the guide cylinder through the long rod, the plug is inserted into the central hole of the guide cylinder, and the positioning hole at the bottom of the cushion block is matched with the anti-rotation pin to realize the positioning of the cushion block and the upper cover plate of the guide cylinder;

[0020] Step 7: operate the screwing tool, guide its outer hexagonal screwing head through the guide cup, and insert it into the inner hexagonal hole of the bolt;

[0021] Step 8: remotely rotate the long rod to screw the bolt;

[0022] Step 9: sequentially screw the bolts at the three positions to the required torque value, that is, the installation of the cushion block is completed, and then the long rod is removed;

[0023] Step 10: supply gas to the lower cylinder of the cylinder, move the cylinder piston rod upward, drive the driving rod to move upward, drive the claws to close, and the claws are separated from the inner tapered surface of the cushion block, and the claws are lifted and taken away.

[0024] The beneficial effects of the present application are that the cylinder drives the opening and closing of the claws, realizes the clamping of the cushion block, and at the same time, through the built-in spring, ensures that the claws are in the open state when the gas is lost, preventing the cushion block from falling. The bolt and the locking cap are lifted and transported together with the cushion block, and at the same time, have the function of preventing falling, realizing the integrated operation of clamping, transmission, positioning and screwing of the cushion block. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram for cushion block installation;

[0026] Figure 2 It is a sectional view of cushion block installation;

[0027] Figure 3 It is a process diagram for cushion block installation;

[0028] Figure 4 It is a screwing diagram for cushion block installation.

[0029] In the figure, 1 is a guide cylinder upper cover plate; 2 is a cushion block; 3 is a grab; 4 is a screwing tool; 11 is an anti-rotation pin; 12 is a center hole; 21 is a bolt; 22 is a locking cap; 31 is a plug; 32 is a claw; 33 is a driving rod; 34 is a cylinder piston rod; 35 is a guide cup; 36 is a positioning pin; 37 is a spring; 38 is a disc; 41 is an outer hexagonal screwing head; and 42 is a long rod. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0031] The present application provides a device for relieving the remote installation of cushion blocks of a heat shield, for positioning and installing the relief cushion block on the upper cover plate of the control rod guide cylinder, and fastening the bolt.

[0032] The technical scheme of the present application is:

[0033] 1) For the clamping of the pad, a special gripper is designed, which adopts a center hole structure of the gripper jaw, and opens and closes the gripper jaw by the driving of the cylinder to realize the clamping and axial fixation of the pad, and realizes the circumferential positioning of the gripper and the pad through the cooperation between the gripper positioning pin and the anti-rotation pin on the pad positioning hole.

[0034] 2) For the installation and positioning of the pad, the positioning is realized through the cooperation between the positioning hole of the pad flange surface and the anti-rotation pin on the upper cover plate of the guide cylinder.

[0035] 3) For the screwing of the bolt, a long rod operating tool is adopted, which is externally hexagonal at the lower part, and is inserted into the inner hexagonal head of the bolt to realize cooperation and perform screwing operation until the required torque value is reached.

[0036] As shown in Figure 1 , a device for relieving the remote installation of the pad of the heat insulation sleeve includes a gripper 3 and a screwing tool 4.

[0037] As shown in Figure 2 , the gripper 3 includes a plug 31, a gripper jaw 32, a driving rod 33, a cylinder piston rod 34, a spring 37, a guide cup 35, a positioning pin 36 and a disc 38.

[0038] The gripper 3 is used to hold the pad 2, the bolt 21 and the locking cap 22 to install and remove the pad.

[0039] The plug 31 is located in the center of the gripper 3, and when the pad 2 is grabbed, it is inserted into the center hole of the pad 2 for clamping and locking, and when the pad is installed, it is inserted into the center hole 12 of the upper cover plate 1 of the guide cylinder for positioning and installation.

[0040] The gripper jaw 32 has three, which are evenly arranged on the plug 31 through the pin shaft, and swing around the pin shaft to realize folding and opening.

[0041] The upper end of the driving rod 33 is connected with the cylinder piston rod 34, which moves up and down under the action of the cylinder; the lower end is in contact with the wedge surface of the gripper jaw 32. When the cylinder inlet is filled with air, the cylinder piston rod 34 drives the driving rod 33 to move upwards, which drives the gripper jaw 32 to fold, and realizes the separation of the gripper 3 and the pad 2; when the cylinder inlet is filled with air, the cylinder piston rod 34 drives the driving rod 33 to move downwards, which drives the gripper jaw 32 to open, clamps the inner tapered surface of the pad, and realizes the fixation of the gripper 3 and the pad 2.

[0042] The spring 37 is in a compressed state between the cylinder and the driving rod 33, and when the cylinder loses air, the compression force of the spring 37 makes the driving rod 33 in the lower position, so that the gripper jaw 32 keeps open state, preventing the gripper 3 and the pad 2 from loosening, which is a safety guarantee measure.

[0043] The screwing tool comprises a long rod 42 and an outer hexagonal screw head 41, the end of the long rod 42 is connected with the outer hexagonal screw head 41, the guide cups 35 are three, are uniformly arranged at the bolt positions, and guide the long rod 42 and the outer hexagonal screw head 41, so that the outer hexagonal screw head 41 is located in the inner hexagonal groove of the bolt 21, and the screwing operation on the bolt 21 is realized.

[0044] The positioning pin 36 is fixed on the disc 38 of the grabber 3, is a tapered cylindrical pin, is inserted into the positioning process hole on the flange of the cushion block 2, and realizes the positioning of the grabber 3 and the cushion block 2.

[0045] The application also provides a method for relieving the installation of the cushion block by the heat insulation sleeve, comprising the following steps:

[0046] Step 1: before the installation of the cushion block 2, the bolt 21 and the locking cap 22 are installed on the cushion block;

[0047] Step 2: the lower cylinder of the cylinder is supplied with air, the cylinder piston rod 34 is in the upper position, and the three clamping claws 32 are closed;

[0048] Step 3: when the grabber 3 clamps the cushion block 2, the plug 31 is first inserted into the central hole of the cushion block, and at the same time, the positioning pin 36 is inserted into the positioning process hole on the cushion block to realize the circumferential positioning;

[0049] Step 4: the disc 38 of the grabber is tightly attached to the upper end surface of the cushion block 2;

[0050] Step 5: the upper cylinder of the cylinder is supplied with air, the cylinder piston rod 34 is in the lower position, the three clamping claws 32 are opened, and the fixed clamping between the grabber 3 and the cushion block 2 is realized;

[0051] Step 6: the grabber 3 is transmitted to the upper side of the upper cover plate 1 of the guide cylinder together with the cushion block 2 through the long rod, the plug 31 is inserted into the central hole 12 of the guide cylinder, and the positioning hole at the bottom of the cushion block is matched with the anti-rotation pin 11 to realize the positioning of the cushion block 2 and the upper cover plate 1 of the guide cylinder;

[0052] Step 7: the outer hexagonal screw head 41 of the screwing tool 4 is guided by the guide cup 35 and inserted into the inner hexagonal hole of the bolt 21;

[0053] Step 8: personnel are above the water tank, and the long rod 42 is remotely rotated to realize the screwing of the bolt 21;

[0054] Step 9: the bolts 21 at the three positions are sequentially screwed to the required torque value, that is, the installation of the cushion block is completed, and then the long rod 42 is taken out;

[0055] Step 10: the lower cylinder of the cylinder is supplied with air, the cylinder piston rod 34 is moved upwards, the driving rod 33 is moved upwards, the clamping claw 32 is closed, the clamping claw 32 is separated from the inner tapered surface of the cushion block 2, and the grabber 3 is taken out.

Claims

1. A device for remote installation of heat insulation sleeve relief pads, characterized in that: It includes a gripper and a screwdriver. The gripper is used to hold the pad, bolt and locking cap for installing and removing the pad. The screwdriver is used to position the relief pad onto the control rod guide tube cover and tighten the bolts. The gripper includes a plug, grippers, a drive rod, a cylinder piston rod, a spring, a guide cup, a positioning pin, and a disc. The plug is located in the center of the gripper. The upper end of the drive rod is connected to the cylinder piston rod, and the lower end contacts the wedge surface of the gripper. When air enters from the lower end of the cylinder, the cylinder piston rod drives the drive rod upward, causing the gripper to retract and separating the gripper from the pad. When air enters from the upper end of the cylinder, the cylinder piston rod drives the drive rod downward, causing the gripper to open and clamp the inner conical surface of the pad, thus fixing the gripper to the pad. The spring is in a compressed state between the cylinder and the drive rod. When the cylinder loses air, the compression force of the spring causes the drive rod to be in the lower position, keeping the gripper open and preventing the gripper from becoming loose from the pad. The screwing tool includes a long rod and an external hexagonal screwing head, with the end of the long rod connected to the external hexagonal screwing head; The gripper has three claws evenly arranged on the plug via pins, and swings around the pins to retract and open; The guide cups are three evenly distributed at the bolt positions; The positioning pin is fixed on the disc of the gripper and is a tapered cylindrical pin. It is inserted into the positioning process hole on the flange of the pad to achieve positioning of the gripper and the pad.

2. A method for remote installation of heat insulation sleeve relief pads, characterized in that, Using the device for remote installation of a heat insulation sleeve relief pad as described in claim 1 includes the following steps: Step 1: Before installing the pad, first install the bolts and locking caps on the pad; Step 2: The lower cylinder is supplied with air, the cylinder piston rod is in the upper position, and the three grippers retract. Step 3: When the gripper picks up and holds the pad, the plug is first inserted into the center hole of the pad, and at the same time, the positioning pin is inserted into the positioning process hole on the pad for circumferential positioning. Step 4: Press the gripper's disc firmly against the upper surface of the pad; Step 5: The upper cylinder is supplied with air, the cylinder piston rod is in the lower position, the three grippers are spread open, and the gripper is fixedly clamped to the pad block; Step 6: Transfer the gripper and the pad together through the long rod to the top of the guide cylinder cover plate. Insert the plug into the center hole of the guide cylinder. The positioning of the pad and the guide cylinder cover plate is achieved by the positioning hole at the bottom of the pad and the anti-rotation pin. Step 7: Operate the screwing tool, guide its external hexagonal screwing head through the guide cup, and insert it into the internal hexagonal hole of the bolt; Step 8: Remotely rotate the long rod to tighten the bolt; Step 9: Tighten the bolts in the three positions to the required torque value in sequence to complete the installation of the pad, and then remove the long rod; Step 10: Supply air to the lower cylinder of the cylinder, the cylinder piston rod moves upward, driving the drive rod to move upward, causing the gripper to retract, the gripper to disengage from the inner conical surface of the pad, and the gripper is lifted out.

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