Modular construction method for VVER type dome penetration piece

Abstract

The invention belongs to a construction method, and particularly relates to a modular construction method of a VVER type dome penetration piece. The modular construction method for the VVER type dome penetration piece comprises the following steps that firstly, preconditions are checked; 2, the civil engineering sleeve is transferred to a workshop; thirdly, the civil engineering sleeve and the penetration piece are welded in a workshop; step 4, introducing a penetration piece module; 5, fixing and protecting; and sixthly, modular construction of the penetration piece is conducted. The method has the remarkable effects that the sleeve is directly transferred to our party to be welded in a workshop, the time for waiting for the civil engineering sleeve to be in place on site is shortened, welding work can be completed in the workshop in a centralized mode, the construction period is prolonged, and personnel waiting consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to construction methods, and particularly relates to a method for modular construction of VVER reactor dome penetrations. Background Art

[0002] The internal and external structures of the VVER reactor building are double containment shells. The penetrations are key components that ensure the tight connection between the inside and outside when the pipelines pass through the double containment shells, and can meet the design requirements of the system pipelines under various working conditions while ensuring the airtightness and integrity of the containment. The installation of the pipeline penetrations includes two parts: the penetration body and the sealing ring. According to the construction methods of the same type of nuclear power plants built in China so far:

[0003] 1) For the dome penetrations, the civil construction unit first fixes the civil sleeve to the double shells of the nuclear island, then introduces the penetration body into the civil sleeve, and then welds the body to the civil sleeve.

[0004] 2) After the dome penetrations are welded to the civil sleeves, the upstream and downstream pipelines are welded to connect the inside and outside of the nuclear island.

[0005] 3) The welding work of the dome penetrations needs to be carried out on a scaffold with a height difference of 15 meters. The risk of working at heights is relatively high, and the difficulty of hoisting and fixing measures is relatively large.

[0006] This installation method has problems such as a long construction period restricted by the positioning of the civil sleeves, low construction efficiency, high safety risks, high quality control difficulty, a long occupation of the main construction period of the dome, large construction period losses, idling of construction personnel, and high labor costs. Summary of the Invention

[0007] Aiming at the defects of the prior art, the present invention provides a method for modular construction of VVER reactor dome penetrations.

[0008] The present invention is implemented as follows: A method for modular construction of VVER reactor dome penetrations, including the following steps:

[0009] Step 1: Prerequisite inspection;

[0010] Step 2: Hand over the civil sleeve to the workshop;

[0011] Step 3: Weld the civil sleeve and the penetration in the workshop;

[0012] Step 4: Introduce the penetration module;

[0013] Step 5: Fix and protect;

[0014] Step 6: Modular construction of the penetrations.

[0015] A method for modular construction of VVER reactor dome penetrations as described above, wherein step one includes the following content:

[0016] 1) The dome penetration position is smooth and free of debris.

[0017] 2) The penetrations have been transported to the site as required. The penetration sleeves have been received from the civil engineering work and their identification and specifications have been checked and meet the requirements.

[0018] 3) The passage in the installation area is unobstructed and the construction site is ready for installation.

[0019] 4) The civil engineering construction meets the installation requirements and the construction risk prevention measures have been implemented.

[0020] 5) Check that the specifications and models of the penetrations meet the design requirements and that the appearance of the penetrations is not damaged.

[0021] 6) The penetration identification is consistent with the installation position. The identification should include the following data: name of the manufacturer, name of the penetration, serial number, production date, design pressure, design temperature, type of working medium, classification, grouping and grading of seismic stability, KKS code of the penetration, weight, etc.

[0022] 7) Measure the dimensions of the penetrations and fittings. If any dimension discrepancies, missing fittings or damage are found, notify the manufacturer for handling as soon as possible.

[0023] 8) Check whether the civil engineering construction meets the installation requirements and whether the construction area and environment meet the construction requirements. If not, notify the upstream unit for coordination in a timely manner.

[0024] A method for modular construction of VVER reactor dome penetrations as described above, wherein step two includes the following content:

[0025] Transport the civil engineering sleeve to the workshop, perform pre-cleaning on the civil engineering sleeve, remove the dirt on the civil engineering sleeve, with the criterion that no visible dirt remains, measure the dimensions of the civil engineering sleeve, and verify with the preset drawings. After the above is completed, proceed to the subsequent steps.

[0026] A method for modular construction of VVER reactor dome penetrations as described above, wherein step three includes the following content:

[0027] Reinforce the civil engineering sleeve, and after reinforcement, weld the penetration to the civil engineering sleeve.

[0028] A method for modular construction of VVER reactor dome penetrations as described above, wherein step four includes the following content:

[0029] Lift and install the welded penetration and civil engineering sleeve combined module to the preset position.

[0030] A method for modular construction of a VVER reactor dome penetration, as described above, wherein step five includes the following contents:

[0031] Install a reinforcement device outside the penetration and civil engineering sleeve combination module. The reinforcement device is composed of four angle steels with a specification of ∠150*15 and a material of Q355B, which are evenly arranged. One end is welded to the outermost flange surface of the sleeve, and the other end is welded to the stiffening rib plate of the dome steel lining. After completion, check whether it is firmly installed.

[0032] A method for modular construction of a VVER reactor dome penetration, as described above, wherein step six includes the following contents:

[0033] Step 6.1: Transportation and protection of the penetration

[0034] (1) For the incoming items of the penetration and expansion joint, if the groove has been processed, during on-site transportation, the groove position needs to be protected firmly to avoid damage during transportation.

[0035] (2) When using a lifting tool for hoisting, the stainless-steel outer surface should be wrapped with halogen-free ion plastic cloth to prevent the ferrite steel of the chain block from directly contacting the stainless-steel equipment.

[0036] (3) Lay sleepers or wooden boards below during transportation to ensure that it will not be damaged or deformed. According to the installation area and working conditions, use corresponding lifting tools (cranes, chain hoists, transport trolleys, etc.) to place the penetration at the installation position in the installation sequence.

[0037] (4) The transportation, cleaning, maintenance, and protection of the items should meet the relevant requirements.

[0038] Step 6.2: Welding of the penetration in the workshop

[0039] (1) Check whether the KKS code, specification, and model of the penetration body meet the design requirements, whether it matches the casing, the quantity of accessories, and measure the dimensions of the penetration and fittings, and whether the penetration and its fittings are matched.

[0040] (2) The penetration body should be free of grease and rust, and the paint on the carbon-steel surface should not fall off.

[0041] (3) Remove the paint, grease, and rust at the seal weld, with a cleaning width of 20 mm. Wipe the weld gasket ring with a white cloth, and there should be no contaminants and vegetable fibers on the ring.

[0042] (4) Align and level the penetration. Accurately and firmly support and position the adjusted pipe penetration with wooden wedges.

[0043] (5) Inspect the welded joints of the pipe penetrations. Spot welding and welding can only be carried out after passing the inspection, and the welding team should meet the requirements for component alignment before welding.

[0044] (6) Weld the stainless steel penetrations according to the welding requirements for stainless steel components, and strictly follow the corresponding welding data package for welding.

[0045] (7) Before welding, mechanically fix the workpiece using tooling fixtures or temporary supports or preheat the welding position to reduce deformation.

[0046] (8) Visually inspect each layer of the weld seam and record the inspection results and conduct 100% liquid penetrant inspection. For visual inspection, refer to the visual inspection requirements, and for liquid penetrant inspection, refer to the relevant requirements for liquid penetrant inspection.

[0047] (9) In addition to meeting the relevant requirements of the general construction plan for penetrations, the weld seam markings should also meet the requirements in the general description of the drawing documents: the height of welded joints with grades should not exceed 10 mm, and the depth of steel stamps should not exceed 0.3 mm.

[0048] Step 6.3: Hoisting and positioning

[0049] (1) Use a crane inside the dome to lift it from the inside to the outside.

[0050] (2) During the positioning process, handle it with care to prevent damage to the penetrations. For stainless steel pipe penetrations, use nylon slings.

[0051] (3) Install reinforcement measures outside the penetration sleeve. The reinforcement measures use four angle steels with specifications of ∠100*10 and material Q355B, which are evenly arranged and welded on the stiffening rib plates of the dome steel lining. After completion, check whether it is firmly installed.

[0052] (4) When hoisting the penetrations, the relevant regulations of the hoisting and transportation construction requirements for small items should be followed, and the slings should be carefully inspected to prevent accidents such as dropping or collision during hoisting.

[0053] (5) The penetrations of the JNB system are not modularly assembled in the workshop. After the civil engineering sleeve is handed over, the penetrations are introduced before the inner dome is hoisted.

[0054] Step 6.4: Fixing the penetrations

[0055] (1) To avoid interference with the outer dome, after introduction, retract 800 mm. For the penetrations outside the embedded sleeve of the reactor internal containment, use pipe clamps to fix the body, and use lifting straps for fixing on the inner side (one end of the lifting strap is fastened to the equipment support and the other end is fixed to the penetration). The specifications of the lifting straps are selected according to the actual situation on site. The penetrations are wrapped with rubber pads at the fastening points of the pipe clamps to increase friction. Load tests need to be carried out before pipe clamp fixation (conduct tests on two specifications of penetrations respectively).

[0056] (2) After the rollback is completed, the installation work shall be carried out in accordance with the installation construction plan for pipe penetrations.

[0057] Step 6.5: Position inspection

[0058] (1) After the penetration sleeve module is reinforced and adjusted, the position shall be rechecked to ensure that it meets the design tolerance requirements of the penetration sleeve. The welding work of the penetration sleeve module shall be the responsibility of the civil engineering unit;

[0059] (2) After the welding of the penetration sleeve module is completed, recheck whether the installation deviation of the penetration meets the design requirements;

[0060] (2a) The allowable deviation value of the installation position (horizontal and vertical) of the penetration is 10 mm;

[0061] (2b) For the installation of the penetration, the deviation of a line between the center of the outer opening and the center of the inner opening of the penetration is 10 mm;

[0062] (2c) For the installation of the penetration, the difference between the center line of the penetration and the center line of the reactor is ±40 mm.

[0063] (3) After the recheck is completed, the work shall be carried out in accordance with the installation construction plan for pipe penetrations.

[0064] Step 6.6: Inspection and finished product protection of penetrations

[0065] (1) Before the penetration is in place, the outer surface of the penetration shall be completely covered with polyethylene plastic sheeting. Wrap two layers at the pipe opening and fix with tape. The penetration port shall be sealed tightly to prevent dirt from entering;

[0066] (2) After the temporary protection is completed, mark the KKS code of the penetration on the outer surface of the protective layer with paint and handle the temporary handover record with the civil engineering unit;

[0067] (3) The part of the penetration that protrudes from the inner wall of the containment after being in place shall be protected;

[0068] (3a) After the penetration is in place, make a warning sign beside it to prevent others from damaging the protection. At the same time, mark the KKS code of the penetration on the outer surface of the protection device with paint;

[0069] (3b) After the penetration is in place and protected, regular inspections shall be carried out (the inspection period is 1 month) to promptly discover and solve unforeseen problems and take remedial measures.

[0070] (4) There shall be no invasion of pollution, dust, impurities, moisture and sundries, and there shall be no damage to the inside of the penetration;

[0071] (5) If some parts of the packaging or external protection are damaged, the extent of the damage should be determined and, if necessary, partial or complete re-maintenance should be carried out.

[0072] The significant effect of the present invention is that the sleeve of the invention is directly handed over to our workshop for welding, which reduces the waiting time for the civil construction sleeve to be in place on site, and the welding work can be completed in the workshop, which improves the construction period and reduces the waiting time of personnel;

[0073] This invention is welded in the workshop, which reduces the hidden dangers of operation safety during the construction process, reduces the establishment of hot spots, reduces high-altitude operations, and reduces safety risks compared with the previous through-piece construction;

[0074] The invention improves the welding cleanliness requirements in the workshop, provides better control over the protection of finished products, and facilitates inspection work;

[0075] The invention uses the method of connecting the penetration piece and the civil construction sleeve at one time in the workshop, which reduces the difficult welding joints due to the narrow space on site and the construction amount of the air crash welding joints at high altitudes, and reduces the pollution of the pipeline by the welding joints on site, the layout of the power line, and the smoke and dust on site, which can greatly improve the on-site construction environment;

[0076] In terms of scaffolding erection, the traditional installation of penetrations requires the erection of a scaffolding welding platform inside the dome and an inflatable operating platform outside the dome. The erection of the scaffolding requires manpower, material resources and time. During the erection and dismantling of the scaffolding, other installation and construction activities cannot be carried out. After modular assembly, only a platform is needed to temporarily fix the penetrations in place, which saves 15 working days of scaffolding erection time and 10 scaffolding erection workers;

[0077] The invention's penetration weld joints take 12 working days to complete in the workshop prefabrication of 32 sets of penetrations, and there is no need to weld the penetrations and civil engineering casings on site. If welding is done on site, it will take 30 working days to complete the welding on the scaffolding after the civil engineering transfers the dome, saving 18 working days on the overall welding time, and the welding completion time is completed ahead of schedule. Brief Description of the Figures

[0078] Figure 1 Construction process of traditional penetration parts

[0079] Figure 2 Post-construction process of modularization Specific implementation method

[0080] Comparison of process innovation after modular execution adopted by traditional and present invention:

[0081] ​When performing Process 2, in the traditional process, it is necessary to wait for the civil engineering and installation unit to complete the on-site fixed welding of the civil engineering sleeve. In the modular process, the civil engineering sleeve is transferred to us without on-site welding. This change in this process step can avoid the influence of the constraints of the on-site installation of the civil engineering sleeve on the welding of the penetrator body and the sleeve, delay the welding time, and avoid situations such as idling of waiting personnel during the process.

[0082] When performing Process 3, in the traditional process, after the on-site installation of the civil engineering sleeve is completed, we will introduce the penetrator body. In the modular process, the civil engineering sleeve is welded in the workshop. If deformation is found, it should be adjusted in time, and anti-deformation tooling is made. During the welding process, since the civil engineering sleeve is separately transferred to us for welding, compared with the traditional installation process, the lack of reinforcement of civil engineering steel bars and concrete will cause the sleeve to deform during the welding process. In order to prevent the sleeve from deforming during welding, the workshop needs to make anti-deformation devices for reinforcement. The concentricity control tooling for the penetrator consists of a ring-shaped stainless steel plate and bolts. This change in this process step can optimize the welding operation environment, reduce high-altitude operations, reduce the erection of scaffolding, and improve the welding quality.

[0083] When performing Process 4, in the traditional process, the introduced penetrator is welded to the civil engineering sleeve on-site. In the modular process, the penetrator module (the civil engineering sleeve and the penetrator body are integrated) after being welded in the workshop is introduced into the hole reserved in advance by the civil engineering of the dome and lifted from the outside to the inside by a crane outside the dome. The module is positioned according to the drawing requirements, and the civil engineering unit performs the assembly of the module. After the assembly, CNNC 23 performs re-measurement and adjustment. This change in this process step can reduce lifting operations, reduce the use of lifting personnel and lifting machinery.

[0084] When performing Process 5, in the traditional process, foreign object protection is carried out on the open position and the body is wrapped after the penetrator is welded to the civil engineering sleeve. In modular construction, the penetrator module needs to be fixed firmly before the civil engineering unit welds it, and reinforcement measures are installed outside the penetrator sleeve. The reinforcement measures use four angle steels with specifications of ∠150*15 and a material of Q355B, which are evenly arranged, welded at one end to the outermost flange surface of the sleeve, and welded at the other end to the stiffening rib plate of the dome steel lining. After completion, check whether it is installed firmly. This change in this process step can prevent the stability of the penetrator and avoid risks such as falling objects or sliding at high altitudes before civil engineering welding.

[0085] Perform Process 6.1: Transportation and protection of the penetrator

[0086] (1) For the delivered items of the penetrator and the expansion joint, if the groove has been processed, during the on-site transportation process, the groove position needs to be protected firmly to avoid damage during transportation;

[0087] (2) When using a lifting tool for lifting, the stainless steel outer surface should be wrapped with halogen-free ion plastic cloth to prevent the ferrite steel of the chain block from directly contacting the stainless steel equipment;

[0088] (3) Lay sleepers or wooden boards below during transportation to ensure that it will not be damaged or deformed. According to the installation area and working conditions, use corresponding lifting tools (cranes, chain hoists, transport trolleys, etc.) to place the penetrator in the installation position in the installation sequence;

[0089] (4) The transportation, cleaning, maintenance and protection of items shall meet the relevant requirements.

[0090] Perform process 6.2: Welding in the penetrator workshop

[0091] (1) Check whether the KKS code, specifications, and models of the penetrator body meet the design requirements, whether they match the casing, the quantity of accessories, and measure the dimensions of the penetrator and its accessories to check whether the penetrator and its accessories are matched;

[0092] (2) The penetrator body shall be free of grease and rust, and the paint on the surface of carbon steel shall not fall off;

[0093] (3) Remove the paint, grease, and rust at the seal weld, with a cleaning width of 20 mm. Wipe the weld gasket ring with a white cloth, and there should be no contaminants and vegetable fibers on the ring;

[0094] (4) Center and level the penetrator, and use wooden wedges to accurately and firmly support and position the qualified pipeline penetrator;

[0095] (5) Check the weld area of the pipeline penetrator. Spot welding and welding can only be carried out after passing the inspection, and the welding assembly shall meet the requirements of pre-welding component assembly;

[0096] (6) Carry out welding work on the stainless steel penetrator according to the welding requirements of stainless steel components, and the welding shall be carried out strictly in accordance with the corresponding welding data package;

[0097] (7) Before welding, use tooling fixtures or temporary supports to mechanically fix the workpiece or preheat the welding position to reduce deformation;

[0098] (8) Visually inspect each layer of the weld seam and record the inspection results and conduct 100% liquid penetrant inspection. For visual inspection, refer to visual inspection, and for liquid penetrant inspection, refer to the relevant requirements of liquid penetrant inspection;

[0099] (9) In addition to meeting the relevant requirements of the general construction plan for penetrators, the weld seam markings shall also meet the requirements in the general description of the drawing documents: the height of welded joints with grades does not exceed 10 mm, and the depth of steel stamps does not exceed 0.3 mm.

[0100] Perform process 6.3: Lifting and placing in position

[0101] (1) Use a crane to lift it from the inside to the outside inside the dome;

[0102] (2) Be careful and gentle when placing the pipe in place to prevent damage to the penetration parts. For stainless steel pipe penetration parts, use nylon slings;

[0103] (3) Install reinforcement measures on the outside of the penetration sleeve. The reinforcement measures use four angle steels with specifications of ∠100*10 and material Q355B, which are evenly arranged and welded on the reinforcing ribs of the dome steel lining. After completion, check whether they are firmly installed;

[0104] (4) When lifting the penetration parts, the relevant regulations on the lifting and transportation of small items should be followed, and the lifting ropes should be carefully checked to prevent them from falling or being damaged during the lifting process;

[0105] (5) The JNB system penetrations are not modularly assembled in the workshop. After the civil construction sleeve is handed over, the penetration body is introduced before the inner dome is hoisted.

[0106] Execute step 6.4: Fixing the penetration

[0107] (1) To avoid interference with the outer dome, the pipe is introduced and retreated 800mm. The penetration outside the embedded sleeve of the reactor internal containment is fixed to the body with a pipe clamp, and the inner part is fixed with a lifting belt (one end of the lifting belt is fastened to the equipment bracket, and the other end is fixed to the penetration). The specifications of the lifting belt are selected according to the actual situation on site. Rubber pads are used to wrap the penetration at the fastening point of the pipe clamp to increase friction. A load test is required before fixing the pipe clamp (two specifications of penetrations are tested separately);

[0108] (2) After the return is completed, the installation work shall be carried out according to the pipeline penetration installation construction plan.

[0109] Execute step 6.5: Positioning check

[0110] (1) After the penetration sleeve module is reinforced and adjusted, the position is checked to ensure that it meets the design tolerance requirements of the penetration sleeve. The welding work of the penetration sleeve module is the responsibility of the civil engineering unit;

[0111] (2) After the penetration sleeve module is welded, retest whether the penetration installation deviation meets the design requirements;

[0112] (2a) The allowable deviation of the installation position (horizontal and vertical) of the penetration piece is 10mm;

[0113] (2b) For the installation of penetrations, the deviation between the center of the outer opening of the penetration and the center of the inner opening of the penetration is 10 mm;

[0114] (2c) For the installation of penetrations, the difference between the centerline of the penetration and the centerline of the reactor is ±40 mm.

[0115] (3) The work after retesting is carried out according to the pipeline penetration installation construction plan.​​​

[0116] Perform process 6.6: Inspection and finished product protection of penetrations

[0117] (1) Before the penetrations are in place, the outer surface of the penetrations shall be completely wrapped with polyethylene plastic sheeting. Wrap two layers at the pipe openings and fix with tape. The ports of the penetrations shall be sealed tightly to prevent dirt from entering;

[0118] (2) After the temporary protection is completed, mark the KKS code of the penetrations on the outer surface of the protective layer with paint and handle the temporary handover record with the civil engineering unit;

[0119] (3) The part of the penetrations protruding from the inner wall of the containment after being in place shall be protected;

[0120] (3a) After the penetrations are in place, make a warning sign beside them to prevent others from damaging the protection. At the same time, mark the KKS code of the penetrations on the outer surface of the protection device;

[0121] (3b) After the penetrations are in place and protected, regular inspections shall be carried out (the inspection period is 1 month) to promptly discover and solve unforeseen problems and take remedial measures.

[0122] (4) There shall be no invasion of pollution, dust, impurities, moisture and sundries, and there shall be no damage inside the penetrations;

[0123] (5) If some positions of the packaging and outer protection are damaged, determine the degree of damage and, if necessary, implement partial or full re-maintenance.

Claims

1. A method for modular construction of VVER dome penetrations, characterized in that: The steps include: Step 1: Prerequisites check; Step 2: Civil construction sleeve is handed over to the workshop; Step 3: Welding of civil engineering sleeve and penetration parts in workshop; Step 4: Introduction of penetration module; Step 5: Fixed protection; Step 6: Modular construction of penetration parts.

2. A method for modular construction of a VVER dome penetration as claimed in claim 1, characterized in that: The step 1 includes the following contents: 1) The dome penetration position is smooth and free of debris; 2) The penetrations have been transported to the site as required, and the sleeves have been received from the civil engineering department and checked for markings and specifications that meet the requirements; 3) The passages in the installation area are unobstructed and the construction site is ready for installation; 4) Civil construction meets the requirements for installation work, and construction risk prevention measures have been implemented; 5) Check that the specifications and models of the penetrations meet the design requirements, and that the appearance of the penetrations is free of damage; 6) The penetration mark should be consistent with the installation position, and the mark should include the following data: manufacturer name, penetration name, serial number, production year and month, design pressure, design temperature, working medium type, classification, grouping and classification of seismic stability, penetration KKS code, weight, etc.; 7) Measure the dimensions of the penetrations and accessories. If the dimensions do not match or the accessories are incomplete or damaged, Notify the manufacturer as soon as possible; 8) Check whether the civil construction meets the installation requirements, and whether the construction area and environment meet the construction requirements. If not, promptly notify the upstream unit for coordination.

3. A modular construction method for VVER dome penetrations as claimed in claim 2, characterized in that: The step 2 includes the following contents: Transport the civil engineering sleeve to the workshop, pre-clean it, remove the dirt on it, and make sure that the dirt is invisible to the naked eye. Measure the size of the civil engineering sleeve and verify it with the preset drawing. After completing the above, proceed to the subsequent steps.

4. A method for modular construction of a VVER dome penetration as claimed in claim 3, characterized in that: The step three includes the following contents: The civil engineering sleeve is reinforced, and after reinforcement, the penetration piece is welded to the civil engineering sleeve.

5. A method for modular construction of a VVER dome penetration as claimed in claim 4, characterized in that: The step 4 includes the following contents: Lift the welded penetration and civil engineering sleeve combination module to the preset position.

6. A method for modular construction of a VVER dome penetration as claimed in claim 5, characterized in that: The step five includes the following contents: A reinforcement device is installed outside the combined module of the penetration piece and the civil engineering sleeve. The reinforcement device uses four angle steels with specifications of ∠150*15 and material Q355B, which are evenly arranged. One end is welded to the outermost flange surface of the sleeve, and the other end is welded to the reinforcing rib of the dome steel lining. After completion, check whether it is installed firmly.

7. A modular construction method for VVER dome penetrations as claimed in claim 6, characterized in that: The step six includes the following contents: Step 6.1: Transport and protection of penetrations (1) For the delivery items of penetration parts and expansion joints, if the groove has been processed, the groove position needs to be hard protected during on-site transportation to avoid damage during transportation; (2) When using lifting tools for lifting, the outer surface of stainless steel should be wrapped with halogen-free plastic cloth to prevent the ferrite steel of the hand chain hoist from directly contacting the stainless steel equipment; (3) During transportation, sleepers or wooden boards are laid underneath to ensure that they will not be damaged or deformed. According to the installation area and working conditions, corresponding lifting tools (crane, fall chain, transport trolley, etc.) are used to place the penetration parts in the installation position in the installation order; (4) The transportation, cleaning, maintenance and protection of items shall meet relevant requirements. Step 6.2: Through-hole shop welding (1) Check whether the KKS code, specification and model of the penetration body meet the design requirements, whether it is consistent with the casing, the number of accessories, and measure the dimensions of the penetration and accessories, and whether the penetration and its accessories are matched; (2) The penetration body should be free of grease and rust, and the paint on the carbon steel surface should not fall off; (3) Remove paint, grease and rust from the sealed weld, remove 20mm in width, and wipe the weld gasket with a white cloth. There should be no pollutants or plant fibers on the ring; (4) Center and level the penetrations, and use wooden wedges to accurately and firmly support and position qualified pipeline penetrations; (5) Check the weld joints of the pipeline penetrations. Spot welding and welding can only be carried out after the inspection is qualified. The welding group should meet the requirements of the pre-welding component grouping; (6) Welding of stainless steel penetrations shall be carried out in accordance with the welding requirements of stainless steel components, and welding shall be carried out strictly in accordance with the corresponding welding data package; (7) Before welding, use fixtures or temporary supports to mechanically fix the workpiece or preheat the welding position to reduce deformation; (8) The welds must be visually inspected layer by layer and the inspection results and 100% liquid penetrant inspection must be recorded. For visual inspection, see Visual Inspection. For liquid penetrant inspection, see the relevant requirements for liquid penetrant inspection. (9) In addition to meeting the relevant requirements of the general construction plan for penetration parts, weld markings should also meet the general description of the drawing documents: the height of graded welded joints shall not exceed 10 mm and the depth of the steel stamp shall not exceed 0.3 mm. Step 6.3: Lifting into place (1) Use a crane to lift it from the inside to the outside of the dome; (2) The installation process should be done with care to prevent damage to the penetration parts. Nylon slings should be used for stainless steel pipe penetration parts. (3) Install reinforcement measures on the outside of the penetration sleeve. Four angle steels with a specification of ∠100*10 and a material of Q355B are evenly arranged and welded on the reinforcing ribs of the dome steel lining. After completion, check whether they are firmly installed; (4) When lifting the penetration parts, the relevant regulations on the lifting and transportation of small items should be followed, and the lifting ropes should be carefully checked to prevent them from falling or being damaged during the lifting process; (5) The JNB system penetrations are not assembled in a modular manner in the workshop. After the civil construction sleeve is handed over, the penetration body is introduced before the inner dome is hoisted. Step 6.4: Fixing the penetration (1) To avoid interference with the outer dome, the pipe is introduced and retreated 800mm. The penetration outside the embedded sleeve of the reactor internal containment is fixed to the body with a pipe clamp, and the inner side is fixed with a lifting belt (one end of the lifting belt is fastened to the equipment bracket, and the other end is fixed to the penetration). The specifications of the lifting belt are selected according to the actual situation on site. Rubber pads are used to wrap the penetration at the fastening point of the pipe clamp to increase friction. A load test is required before fixing the pipe clamp (test the penetrations of two specifications separately); (2) After the rollback is completed, the installation work is carried out according to the pipeline penetration installation construction plan. Step 6.5: Positioning check (1) After the penetration sleeve module is reinforced and adjusted, the position is checked to ensure that it meets the design tolerance requirements of the penetration sleeve. The welding work of the penetration sleeve module is the responsibility of the civil engineering unit; (2) After the penetration sleeve module is welded, retest whether the penetration installation deviation meets the design requirements; (2a) The allowable deviation of the installation position (horizontal and vertical) of the penetration piece is 10 mm; (2b) For the installation of penetrations, the deviation between the center of the outer opening of the penetration and the center of the inner opening of the penetration is 10 mm; (2c) For the installation of penetrations, the difference between the centerline of the penetration and the centerline of the reactor shall be ±40 mm. (3) The work after the retest is completed shall be carried out according to the pipeline penetration installation construction plan. Step 6.6: Inspection of penetrations and protection of finished products (1) Before the penetration is in place, the outer surface of the penetration should be completely covered with polyethylene plastic sheeting, with two layers of plastic sheeting at the pipe opening, and fixed with tape. The end of the penetration should be tightly sealed to prevent dirt from entering; (2) After the temporary protection is completed, the KKS code of the penetration shall be marked on the outer surface of the protective layer with paint, and the temporary handover record shall be submitted to the civil engineering unit; (3) After being installed, the part of the penetration exposed from the inner wall of the containment should be protected; (3a) After the penetration is in place, a warning sign is made next to it to prevent others from damaging the protection. At the same time, the KKS code of the penetration is marked on the outer surface of the protection device with paint; (3b) After the penetrations are in place and protected, they should be inspected regularly (inspection cycle is 1 month) to promptly detect and resolve unexpected problems and take remedial measures. (4) There shall be no pollution, dust, impurities, moisture and debris intrusion, and the inside of the penetration shall not be damaged; (5) If some parts of the packaging or external protection are damaged, the extent of the damage should be determined and, if necessary, partial or complete re-maintenance should be carried out.

Images