Device and method for remote installation of heat insulation sleeve relieving cushion block

Abstract

The invention belongs to the technical field of nuclear power, and particularly relates to a device and method for remote installation of a heat insulation sleeve relieving cushion block. Comprising a gripping apparatus and a screwing tool, the gripping apparatus is used for gripping the cushion block, the bolt and the locking cap to mount and dismount the cushion block, and the screwing tool is used for positioning and mounting the relieving cushion block on the upper cover plate of the control rod guide cylinder and fastening the bolt. The clamping device has the beneficial effects that the air cylinder is adopted to drive the grabhooks to be opened and closed, clamping of the cushion block is achieved, meanwhile, it is guaranteed that the grabhooks are in an open state during air loss through the built-in springs, and the cushion block is prevented from falling off. A grabbing structure that the bolts and the locking caps are lifted along with the cushion blocks is adopted, meanwhile, the anti-falling function is achieved, and integrated operation of clamping, conveying, positioning and screwing of the cushion blocks is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power, and in particular relates to a device and method for remote installation of a thermal insulation sleeve relief pad. Background Art

[0002] The thermal sleeve is a component of the control rod drive mechanism (CRDM) and is suspended from the CRDM socket on the pressure vessel head. It is installed with a radial clearance fit and no axial constraints. During unit operation, the thermal sleeve is subject to vibrations induced by the primary flow, causing friction between the upper end and the CRDM socket flange, resulting in a drop in the sleeve's height. Over time, wear on the sleeve's end causes the sleeve to drop further. If not addressed, the sleeve will continue to settle, eventually wearing away completely and causing the entire sleeve to fall.

[0003] Currently, a common mitigation measure involves installing a mitigation pad on the upper cover of the control rod guide cylinder, an upper core component. The pad consists of a cone and a flange, with three sets of evenly spaced bolts and locking caps on the flange. The flange has two evenly spaced locating holes underneath. The pad is positioned by the locating holes mating with anti-rotation pins on the guide cylinder's upper cover. The pad is secured with three sets of bolts, and the locking caps that work with the bolts prevent loosening.

[0004] Because the guide cylinder's exposure dose is approximately 15mSv / h, it requires shielding with boric acid water. Therefore, the installation of the spacer on the upper end face of the guide cylinder must be performed underwater. The guide cylinder is immersed in boric acid water (concentration 2400-2500ppm), and the operator performs remote control from an auxiliary bridge above the pool. The entire installation process includes clamping, transporting, positioning, and tightening the spacer. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for remote installation of an insulation sleeve relief pad, which can integrate clamping, transmission, positioning and screwing, and is used for underwater remote installation of the relief pad, and the relief pad is installed on the upper end face of the control rod guide cylinder and fastened securely.

[0006] The technical solution of the present invention is as follows: a device for remotely installing a thermal insulation sleeve relief pad, comprising a gripper and a screwing tool. The gripper is used to grip the pad, bolts, and locking cap to install and remove the pad. The screwing tool is used to position and install the relief pad on the upper cover plate of the control rod guide cylinder and tighten the bolts. The gripper includes a plug, a gripper, 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 is introduced into the lower port of the cylinder, the cylinder piston rod drives the drive rod to move upward, driving the gripper to retract, thereby separating the gripper from the pad; when air is introduced into the upper port of the cylinder, the cylinder piston rod drives the drive rod to move downward, driving the gripper to open, clamping the inner conical surface of the pad, thereby fixing the gripper to the pad.

[0007] The spring is in a compressed state and is located between the cylinder and the drive rod. When the cylinder loses air, the compression force of the spring causes the drive rod to be located in a lower position, so that the claw remains in an open state, thereby preventing the gripper from loosening from the pad.

[0008] The screwing tool comprises a long rod and an external hexagonal screwing head, and the end of the long rod is connected to the external hexagonal screwing head.

[0009] There are three guide cups evenly arranged at the bolt positions.

[0010] 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 pad flange to achieve the positioning of the gripper and the pad.

[0011] The three grippers are evenly arranged on the plug through a pin shaft and can be folded and opened by swinging around the pin shaft.

[0012] A method for remotely installing a thermal insulation sleeve relief pad includes the following steps: Step 1: Before installing the spacer, install the bolts and locking caps on the spacer; Step 2: The air cylinder is lowered and supplied with air. The piston rod of the cylinder is in the upper position and the three grippers are retracted. Step 3: When the gripper grabs and clamps 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: Place the gripper's disc close to the upper end of the pad; Step 5: The air cylinder is supplied with air, the cylinder piston rod is in the lower position, and the three claws are stretched open to achieve fixed clamping between the gripper and the pad; Step 6: Transfer the gripper together with the pad through the long rod to the top of the guide cylinder cover. Insert the plug into the center hole of the guide cylinder. Use the positioning hole at the bottom of the pad to cooperate with the anti-rotation pin to achieve the positioning of the pad and the guide cylinder cover. Step 7: Operate the screwing tool, guide its external hexagonal screw 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 at the three positions in sequence to the required torque value, completing the installation of the pad, and then remove the long rod; Step 10: Supply air to the lower cylinder of the air cylinder, and the cylinder piston rod moves upward, driving the drive rod to move upward, driving the gripper to retract, and the gripper disengages from the inner conical surface of the pad, and the gripper is lifted up and removed.

[0013] The beneficial effects of the present invention are: a pneumatic cylinder drives the gripper to open and close, achieving gripping of the cushion block. Simultaneously, a built-in spring ensures that the gripper remains open in the event of air loss, preventing the cushion block from falling. A gripping structure in which the bolt and locking cap are hoisted along with the cushion block also provides a fall prevention function, achieving integrated gripping, transporting, positioning, and screwing of the cushion block. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the pad installation; Figure 2 Provide a cross-sectional view of the spacer installation; Figure 3 The installation process drawing for the pad; Figure 4 Screw diagram for spacer installation.

[0015] In the figure, 1. Guide cylinder upper cover plate; 2. Spacer block; 3. Gripper; 4. Twist tool; 11. Anti-rotation pin; 12. Center hole; 21. Bolt; 22. Locking cap; 31. Plug; 32. Gripper; 33. Drive rod; 34. Cylinder piston rod; 35. Guide cup; 36. Positioning pin; 37. Spring; 38. Disc; 41. Hexagonal screwdriver; 42. Long rod. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] The present invention provides a device for remotely installing a thermal insulation sleeve relief pad, which is used for positioning and installing the relief pad on an upper cover plate of a control rod guide cylinder and tightening bolts.

[0018] The technical solution for realizing the present invention is: 1) In order to clamp the pad, a special gripper is designed, which adopts a claw-operated center hole structure. The gripper is driven by a cylinder to open and close to achieve clamping and axial fixation of the pad. The circumferential positioning of the gripper and the pad is achieved by the cooperation between the gripper locating pin and the pad positioning process hole.

[0019] 2) For the installation and positioning of the pad, positioning is achieved by cooperating with the positioning hole on the ground of the pad flange and the anti-rotation pin on the upper cover of the guide cylinder.

[0020] 3) For tightening the bolts, use a long-rod operating tool with an external hexagon at the bottom. Insert the internal hexagon head of the bolt through the guide to achieve fit, and then perform the tightening operation until the required torque value is reached.

[0021] As shown in Figure 1 A device for the remote installation of a spacer pad for a heat shield, comprising a grabber 3 and a screwing tool 4.

[0022] As shown in Figure 2 The grabber 3 comprises a plug 31, a grab claw 32, a drive rod 33, a cylinder piston rod 34, a spring 37, a guide cup 35, a positioning pin 36 and a disc 38.

[0023] The grabber 3 is used to grab the spacer pad 2, the bolt 21 and the locking cap 22, and to install and remove the spacer pad.

[0024] The plug 31 is located in the center of the grabber 3, and when the spacer pad 2 is grabbed, it is inserted into the center hole of the spacer pad 2 for clamping and locking, and when the spacer pad is installed, it is inserted into the center hole 12 of the guide cylinder upper cover plate 1 for positioning and installation.

[0025] The grab claw 32 has three, which are evenly arranged on the plug 31 through a pin shaft, and are swung around the pin shaft to realize folding and opening.

[0026] The upper end of the drive 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 grab claw 32. When the cylinder inlet is filled with air, the cylinder piston rod 34 drives the drive rod 33 to move upwards, which drives the grab claw 32 to fold, and the grabber 3 is separated from the spacer pad 2; when the cylinder inlet is filled with air, the cylinder piston rod 34 drives the drive rod 33 to move downwards, which drives the grab claw 32 to open, clamping the inner tapered surface of the spacer pad, and the grabber 3 is fixed with the spacer pad 2.

[0027] The spring 37 is in a compressed state between the cylinder and the drive rod 33, and when the cylinder loses air, the compression force of the spring 37 makes the drive rod 33 in the lower position, so that the grab claw 32 remains in the open state, preventing the grabber 3 from being separated from the spacer pad 2, which is a safety measure.

[0028] 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 cup 35 has three, which are evenly arranged at the bolt position, providing guidance for the long rod 42 and the outer hexagonal screw head 41, facilitating the outer hexagonal screw head 41 to be located in the inner hexagonal groove of the bolt 21, and realizing the screwing operation of the bolt 21.

[0029] The positioning pin 36 is fixed on the disc 38 of the grabber 3, which is a tapered cylindrical pin, which is inserted into the positioning process hole on the flange of the spacer pad, realizing the positioning of the grabber 3 and the spacer pad 2.

[0030] The application also provides a method for the remote installation of a spacer pad for a heat shield, comprising the following steps: Step 1: Before installing the spacer pad 2, install the bolt 21 and the locking cap 22 on the spacer pad; Step 2: The air cylinder is lowered to supply air, the cylinder piston rod 34 is in the upper position, and the three gripping claws 32 are retracted; Step 3: When the gripper 3 grabs and clamps the cushion block 2, the plug 31 is first inserted into the center hole of the cushion block, and the positioning pin 36 is inserted into the positioning process hole on the cushion block to perform circumferential positioning; Step 4: Place the gripper's disc 38 firmly against the upper end surface of the pad 2; Step 5: The air cylinder is supplied with air, the cylinder piston rod 34 is in the lower position, and the three claws 32 are stretched open to achieve fixed clamping between the gripper 3 and the pad 2; Step 6: The gripper 3 and the pad 2 are transferred to the upper part of the guide cylinder cover 1 through the long rod. The plug 31 is inserted into the central hole 12 of the guide cylinder. The positioning hole at the bottom of the pad cooperates with the anti-rotation pin 11 to achieve the positioning of the pad 2 and the guide cylinder cover 1. Step 7: Operate the screwing tool 4, guide its external hexagonal screwing head 41 through the guide cup 35, and insert it into the internal hexagonal hole of the bolt 21; Step 8: A person above the pool remotely rotates the long rod 42 to tighten the bolt 21; Step 9: Tighten the bolts 21 at the three positions in sequence to the required torque value, thus completing the installation of the spacer. Then, remove the long rod 42. Step 10: Supply air to the lower cylinder of the cylinder, the cylinder piston rod 34 moves upward, driving the drive rod 33 to move upward, driving the claw 32 to retract, the claw 32 to disengage from the inner conical surface of the pad 2, and the gripper 3 is lifted up and taken away.

Claims

1. A device for remote installation of thermal insulation sleeve relief pads, characterized by: It includes a gripper and a screwing tool. The gripper is used to grasp the spacer, bolts and locking cap to install and remove the spacer. The screwing tool is used to position the relief spacer onto the upper cover of the control rod guide cylinder and tighten the bolts. The gripper includes a plug, a gripper, 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 is introduced into the lower port of the cylinder, the cylinder piston rod drives the drive rod to move upward, driving the gripper to retract, thereby separating the gripper from the pad; when air is introduced into the upper port of the cylinder, the cylinder piston rod drives the drive rod to move downward, driving the gripper to open, clamping the inner conical surface of the pad, thereby fixing the gripper to the pad.

2. The device for remote installation of a thermal insulation sleeve relief pad according to claim 1, characterized in that: The spring is in a compressed state and is located between the cylinder and the drive rod. When the cylinder loses air, the compression force of the spring causes the drive rod to be located in a lower position, so that the gripper remains in an open state, thereby preventing the gripper from loosening from the pad.

3. The device for remote installation of a thermal insulation sleeve relief pad according to claim 1, characterized in that: The screwing tool comprises a long rod and an external hexagonal screwing head, and the end of the long rod is connected to the external hexagonal screwing head.

4. The device for remote installation of a thermal insulation sleeve relief pad according to claim 1, characterized in that: There are three guide cups evenly arranged at the bolt positions.

5. The device for remote installation of a thermal insulation sleeve relief pad according to claim 1, characterized in that: 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 cushion block to achieve the positioning of the gripper and the cushion block.

6. The device for remote installation of a thermal insulation sleeve relief pad according to claim 1, characterized in that: The three grippers are evenly arranged on the plug through a pin shaft and can be folded and opened by swinging around the pin shaft.

7. A method for remote installation of thermal insulation sleeves to relieve pads, characterized in that: Using a device for remote installation of a thermal insulation sleeve to alleviate a pad according to any one of claims 1 to 6 comprises the following steps: Step 1: Before installing the spacer, install the bolts and locking caps on the spacer; Step 2: The air cylinder is lowered and supplied with air. The piston rod of the cylinder is in the upper position and the three grippers are retracted. Step 3: When the gripper grabs and clamps 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: Place the gripper's disc close to the upper end of the pad; Step 5: The air cylinder is supplied with air, the cylinder piston rod is in the lower position, and the three claws are stretched open to achieve fixed clamping between the gripper and the pad; Step 6: Transfer the gripper together with the pad through the long rod to the top of the guide cylinder cover. Insert the plug into the center hole of the guide cylinder. Use the positioning hole at the bottom of the pad to cooperate with the anti-rotation pin to achieve the positioning of the pad and the guide cylinder cover. Step 7: Operate the screwing tool, guide its external hexagonal screw 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 at the three positions in sequence to the required torque value, completing the installation of the pad, and then remove the long rod; Step 10: Supply air to the lower cylinder of the air cylinder, and the cylinder piston rod moves upward, driving the drive rod to move upward, driving the gripper to retract, and the gripper disengages from the inner conical surface of the pad, and the gripper is lifted up and removed.

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