CN112607576A - Lifting appliance and lifting process for main bolt of nuclear reactor pressure vessel - Google Patents

Abstract

The invention belongs to the technology of nuclear power station maintenance, and particularly relates to a lifting appliance for a main bolt of a nuclear reactor pressure vessel and a lifting process. The lifting appliance comprises a sleeve and a lifting mechanism, wherein the upper end of the sleeve can move up and down relative to the sleeve, a pressing plate is fixedly arranged at the lower end of the lifting mechanism, the area of the pressing plate is larger than the mounting hole of the lifting mechanism, a through hole is processed in the side wall of the sleeve, a connecting key is mounted in the through hole, and the through hole is welded and fixed. The height of the locking bolt is adjusted by rotating the handle anticlockwise, whether the lifting appliance is right opposite to the groove of the adapter is judged by the welding seam between the outer wall of the sleeve and the connecting key, the sleeve is lifted after the sleeve is in place on the adapter along the groove, and the handle of the locking bolt is rotated clockwise to screw the locking bolt to the bottom. The main bolt hoisting hanger realizes the main bolt hoisting in the state of installing the adapter, so that the whole switch cover operates each main bolt to dismount and mount the main bolt hoisting hanger for 2 times respectively, and the adapters are dismounted and mounted for 1 time respectively, the process is simplified, and the operability is improved.

Description

Lifting appliance and lifting process for main bolt of nuclear reactor pressure vessel

Technical Field

The invention belongs to the technology of nuclear power station maintenance, and particularly relates to a lifting appliance for a main bolt of a nuclear reactor pressure vessel and a lifting process.

Background

A certain nuclear power plant adopts four large-scale nuclear power units, 54 bolt holes are arranged outside a main sealing surface of a nuclear reactor pressure vessel, and 54 through holes are arranged on a top cover. The pressure vessel and the top cover are sealed through a main sealing element (comprising 54 main bolts, 54 main nuts, 54 sets of concave-convex ball gaskets and 2 nickel gaskets).

The nuclear power unit usually adopts 12 months or 18 months as a fuel cycle, partial nuclear fuel must be replaced after each fuel cycle is finished, and the following operations are required: open the reactor pressure vessel (i.e., open lid operation) → refueling → close the pressure vessel (i.e., close lid operation). The whole cover opening and closing operation relates to the maintenance work of the main sealing element, and comprises the following steps: the method comprises the steps of stretching and unscrewing a main bolt, dismantling, locally disassembling, cleaning, checking, thread lubricating, assembling, reinstalling and stretching and pre-tightening the main bolt. The main bolt has a mass of 306Kg, M42 hoisting threads are arranged at the top of the main bolt for hoisting, and meanwhile, a manufacturer is matched with a special hoisting tool. In order to improve the working quality and efficiency, a special tool, namely a main bolt stretcher, is usually used for opening and closing the cover of the nuclear reactor pressure vessel. In order to realize the rotation and lifting operation of the manipulator to the main bolt and meet the measurement requirement of the elongation of the main bolt, an adapter must be installed at the position of a hoisting hole of each main bolt.

In the prior art, the main seal maintenance procedures are as follows: (1) uncovering: installing an adapter on the kingbolt → releasing the seal using a kingbolt tensioner → dismantling the adapter → installing a kingbolt hanger → dismantling the kingbolt from the head → dismantling the kingbolt hanger; (2) disassembling, cleaning, checking, lubricating and assembling the main sealing element in a nuclear service factory building; (3) and (3) closing the cover: installing the kingbolt hanger → installing the kingbolt to the head → removing the kingbolt hanger → installing the kingbolt adapter → sealing using a kingbolt tensioner → removing the adapter. Wherein each main bolt is at least disassembled and assembled for 2 times respectively in the operation of opening and closing the cover, and each adapter is disassembled and assembled for 2 times respectively. The time of the disassembly and assembly work of the lifting appliance is short, and the time of major repair key paths is not occupied. The removal and installation of 54 adapters requires at least 6 persons 2 hours 1 time, the work is on the key path of overhaul, and the working site is in the reactor shaft, and the environmental radiation dosage rate is high.

The existing main bolt lifting appliance can only be directly connected with the main bolt, the lifting of the main bolt in the adapter mounting state cannot be considered, and the applicability is not strong; the existing main bolt hoisting process is complicated and fussy, and the investment of manpower, material resources and financial resources is large, so that unnecessary dose irradiation and radioactive wastes are generated.

Disclosure of Invention

The invention aims to provide a lifting tool for a main bolt of a nuclear reactor pressure vessel and a lifting process, which can greatly simplify the lifting process and adapt to the condition of installing an adapter.

The technical scheme of the invention is as follows:

the utility model provides a nuclear reactor pressure vessel kingbolt hoist, includes the sleeve, locates the hoist mechanism that sleeve upper end can reciprocate for the sleeve, hoist mechanism lower extreme fixed be equipped with the clamp plate, the area of clamp plate is greater than hoist mechanism's mounting hole, telescopic lateral wall processing have the through-hole, installation connecting key in it to welded fastening.

The lifting mechanism is a locking bolt, and a mounting hole of the lifting mechanism is a threaded hole formed in the upper surface of the sleeve and is in threaded fit with the locking bolt; the lower end of the locking bolt is welded with a pressure plate; the area of the pressure plate is larger than that of the threaded hole.

The center of the upper surface of the sleeve is provided with a cylindrical protruding structure, and the center of the upper surface of the sleeve is provided with a threaded hole which penetrates through the protruding structure.

The locking bolt is connected through threads, is arranged in the protruding structure and penetrates into the sleeve.

And a handle is welded at the upper end of the locking bolt.

The handle is fixed on the top of the locking bolt through a pin.

The sleeve top be equipped with rings, rings lower extreme fixed suit in the telescopic upper end outside.

A lifting appliance for a king bolt of a nuclear reactor pressure vessel and a lifting process for the king bolt comprise the following steps:

step 1), adjusting the height of a locking bolt by rotating a handle anticlockwise until a pressure plate moves back to the top of a sleeve;

step 2) lifting the lifting ring, placing a lifting appliance of the main bolt of the nuclear reactor pressure vessel on the adapter, and judging whether the lifting appliance is over against the groove of the adapter through a welding seam between the outer wall of the sleeve and the connecting key;

step 3) positioning the sleeve on the adapter along the groove, and rotating the sleeve to the bottom anticlockwise;

step 4), lifting the sleeve, rotating a handle of the locking bolt clockwise, screwing the locking bolt to the bottom, and enabling the pressing plate to press the main bolt adapter;

and 5) in order to prevent the locking bolt from being seized, the locking bolt rotates 90 degrees anticlockwise.

The step 2) is specifically as follows:

when the connecting key and the adapter groove are in the same plumb line, the connecting key is judged to be opposite to the adapter groove;

otherwise, the adapter groove is not aligned;

if the adapter groove is not aligned, the hanging ring 1 needs to be rotated clockwise or anticlockwise, so that the connecting key and the adapter groove are located in the same plumb line.

The following steps are included after the step 5):

step 6), lifting the sleeve upwards, and rotating the handle anticlockwise until the pressing plate is completely retracted to the top of the sleeve;

step 7), lifting the handle to drop the sleeve to the bottom;

step 8), rotating the sleeve clockwise to the bottom;

and 9) lifting the handle, and vertically lifting the sleeve upwards along the groove of the adapter to lift the hanger.

The invention has the following remarkable effects: after the main bolt lifting appliance is used, the maintenance process of the main sealing element is changed. (1) Uncovering: installing an adapter on the kingbolt → releasing the seal using a kingbolt stretcher → installing a kingbolt hanger → removing the kingbolt from the head cover → removing the kingbolt hanger; (2) disassembling, cleaning, checking, lubricating and assembling the main sealing element in a nuclear service factory building; (3) and (3) closing the cover: installing the kingbolt hanger → installing the kingbolt onto the roof → removing the kingbolt hanger → sealing using a kingbolt tensioner → removing the adapter. The main bolt hoisting hanger realizes the main bolt hoisting in the state of installing the adapter, so that the whole switch cover operates each main bolt to dismount and mount the main bolt hoisting hanger for 2 times respectively, and the adapters are dismounted and mounted for 1 time respectively, the process is simplified, and the operability is improved.

In addition, the design and connection reliability is high, the sleeve is in threaded connection with the locking bolt, the adapter is pressed through the pressing plate, and the self-locking and anti-falling functions are achieved;

in the whole operation process of opening and closing the cover, the times of detaching and installing the adapter in a reactor plant are reduced from 2 times to 1 time respectively, the operation time is shortened by 50 percent, the key path time of major repair is shortened, the operation time of high-dose environment is shortened, and the irradiated dose of operators is reduced; the improvement of the maintenance efficiency can reduce the times of personnel entering and exiting the radiation pollution isolation area, and reduce the use amount of radiation protection articles and the generation amount of radioactive wastes;

the lifting appliance is simple to operate and high in dismounting efficiency, and the threaded connection adopts a double-thread design, so that the dismounting time of the lifting appliance is shortened.

Drawings

FIG. 1 is a schematic illustration of a kingbolt hanger;

FIG. 2 is a side view of a kingbolt hanger;

in the figure: 1. a hoisting ring; 2. a pin; 3. locking the bolt; 4. a handle; 5. a sleeve; 6. pressing a plate; 7. a connecting key.

Detailed Description

The invention is further illustrated by the accompanying drawings and the detailed description.

As shown in fig. 1 and fig. 2, a lifting appliance for a main bolt of a nuclear reactor pressure vessel is composed of a lifting ring 1, a pin 2, a locking bolt 3, a handle 4, a sleeve 5, a pressure plate 6 and 2 connecting keys 7.

Wherein the sleeve 5

Wherein, the sleeve 5 is a cylindrical protruding structure processed at the center of the upper surface, so that the upper surface of the sleeve 5 is in a ladder shape.

The center of the upper surface of the sleeve 5 is provided with a threaded hole which penetrates through the upper convex structure. Through threaded hole installation locking bolt 3, this locking bolt 3's lower extreme welding clamp plate 6, the surface of clamp plate 6 is greater than locking bolt 3's cross-section, consequently when locking bolt 3 reciprocates for sleeve 5 through threaded connection, drives clamp plate 6 and removes, but the direction obtains the restriction, consequently has the anticreep function.

And meanwhile, the pressing plate 6 is moved downwards, can compress the adapter and has a self-locking function. The adapter is the common device of kingbolt installation, is the implementation object of this application.

Handle 4 is welded at locking bolt 3 upper end, and locking bolt 3's top is locked with pin 2, makes things convenient for the change of handle 4.

The lifting ring 1 is positioned above the sleeve 5, and the lower end of the lifting ring is sleeved outside the upper end of the sleeve 5 and is connected together by welding.

The side wall of the sleeve 5 is provided with a through hole, and a connecting key 7 is arranged in the through hole and is welded and fixed.

The lower end of the sleeve 5 is provided with symmetrical through grooves, and the upper end of the sleeve 5 is provided with an internal thread through hole; the upper part of the locking bolt 3 is provided with a through hole, and the lower part is provided with an external thread.

The hoisting process realized based on the lifting appliance realizes connection and disassembly of the lifting appliance and the main bolt, and specifically comprises the following steps.

The connection method of the hanger and the main bolt is realized based on the hanger.

The method comprises the following steps: the handle 4 is rotated anticlockwise (the rotation direction ensures that the pressure plate 6 rises), and the height of the locking bolt 3 is adjusted until the pressure plate 6 is retracted to the top of the sleeve 5;

step two: lifting the lifting ring 1, placing a lifting appliance of a main bolt of a nuclear reactor pressure vessel on the adapter, and judging whether the lifting appliance is over against the groove of the adapter through a welding seam between the outer wall of the sleeve 5 and the connecting key 7;

the specific judgment method comprises the following steps:

when the connecting key 7 and the adapter groove are in the same plumb line, the connecting key is judged to be opposite to the adapter groove;

otherwise, the adapter groove is not aligned;

if the adapter groove is not aligned, the hanging ring 1 needs to be rotated clockwise or anticlockwise, so that the connecting key 7 and the adapter groove are located in the same plumb line.

Step three: positioning the sleeve 5 on the adapter along the groove, rotating the sleeve 5 counterclockwise to the bottom (36 °);

step four: lifting the sleeve 5, rotating the handle 4 of the locking bolt 3 clockwise, screwing the locking bolt 3 to the bottom, and enabling the pressing plate 6 to press the main bolt adapter;

step five: to prevent the locking bolt 3 from being seized, the locking bolt 3 is rotated 90 degrees counterclockwise;

when the hanger is separated from the main bolt, the subsequent steps are carried out

Step six: lifting the sleeve 5 upwards, and rotating the handle 4 anticlockwise until the pressing plate 6 is completely retracted to the top of the sleeve 5;

step seven: the handle 4 is lifted to drop the sleeve 5 to the bottom;

step eight: rotating sleeve 5 clockwise to the bottom (36 °);

step nine: the handle 4 is lifted and the sleeve 5 is lifted vertically up the adapter groove and out of the sling.

Claims (10)

1. A nuclear reactor pressure vessel main bolt spreader is characterized in that: it comprises a sleeve (5), a lifting mechanism arranged on the upper end of the sleeve (5) and capable of moving up and down relative to the sleeve (5), the lifting mechanism The lower end is fixedly provided with a pressure plate (6), the area of the pressure plate (6) is larger than the installation hole of the lifting mechanism, the side wall of the sleeve (5) is machined with a through hole, the connecting key (7) is installed in it, and is welded and fixed . 2. A nuclear reactor pressure vessel main bolt hanger according to claim 1, characterized in that: the lifting mechanism is a locking bolt (3), and the mounting hole of the lifting mechanism is machined on the upper surface of the sleeve The threaded hole is threaded with the locking bolt (3); the lower end of the locking bolt (3) is welded with a pressure plate (6); the area of the pressure plate (6) is larger than the threaded hole. 3. A nuclear reactor pressure vessel main bolt hanger according to claim 2, characterized in that: a cylindrical convex structure is processed at the center of the upper surface of the sleeve (5), and the sleeve (5) The center of the upper surface is machined with a threaded hole, which penetrates the raised structure on the upper surface. 4. A nuclear reactor pressure vessel main bolt hanger according to claim 3, characterized in that: the locking bolts (3) are connected by threads, installed in the raised structure, and penetrated to the sleeve (5). )Inside. 5. A nuclear reactor pressure vessel main bolt hanger according to any one of claims 1-4, characterized in that: the upper end of the locking bolt (3) is welded with a handle (4). 6 . The main bolt hanger of a nuclear reactor pressure vessel according to claim 5 , wherein the handle ( 4 ) is fixed to the top of the locking bolt 3 through a pin ( 2 ). 7 . 7. A nuclear reactor pressure vessel main bolt hanger according to claim 5, characterized in that: a lifting ring (1) is provided above the sleeve (5), and the lower end of the lifting ring (1) is fixedly sleeved on Outside the upper end of the sleeve (5). 8. A nuclear reactor pressure vessel main bolt hanger and main bolt hoisting process, characterized in that it comprises the following steps: Step 1) Adjust the height of the locking bolt (3) by rotating the handle (4) counterclockwise until the pressure plate (6) retreats to the top of the sleeve (5); Step 2) Lift the lifting ring (1), place the nuclear reactor pressure vessel main bolt spreader on the adapter, and judge whether the spreader is facing the adapter groove through the weld between the outer wall of the sleeve (5) and the connecting key (7); Step 3) Position the sleeve (5) on the adapter along the groove, and rotate the sleeve (5) counterclockwise to the end; Step 4) Lift the sleeve (5), turn the handle (4) of the locking bolt (3) clockwise, and screw the locking bolt (3) to the bottom so that the pressure plate (6) presses the main bolt adapter; Step 5) To prevent the locking bolt (3) from being bitten, the locking bolt (3) is rotated 90 degrees counterclockwise. 9. The method for connecting the main bolt spreader of a nuclear reactor pressure vessel and the main bolt according to claim 8, wherein the step 2) is specifically: When the connecting key (7 and the adapter groove are on the same vertical line, it is judged that the adapter groove is facing; Otherwise, it is not facing the adapter groove; If it is not facing the adapter groove, rotate the lifting ring (1) clockwise or counterclockwise so that the connecting key (7) and the adapter groove are on the same vertical line. 10. The method for connecting the main bolt spreader of a nuclear reactor pressure vessel and the main bolt as claimed in claim 8, wherein after step 5) the following steps are included: Step 6) Lift the sleeve (5) upward, and rotate the handle (4) counterclockwise until the pressure plate (6) is completely retracted to the top of the sleeve (5); Step 7) Hold the handle (4) and drop the sleeve (5) to the bottom; Step 8) Rotate the sleeve (5) clockwise to the end; Step 9) Lift the handle (4), and lift the sleeve (5) vertically upward along the adapter groove to lift the spreader.

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