Hanging basket barrel device for nuclear reactor and welding method of hanging basket barrel device

Abstract

The invention provides a hanging basket barrel device for a nuclear reactor and a welding method of the hanging basket barrel device. The welding method comprises the steps that S1, a bottom plate and a lower barrel are assembled and subjected to spot welding; s2, welding machine guide rails are installed; s3, a welding machine trolley is adopted for conducting circumferential weld joint welding on the bottom plate and the lower barrel; s4, the upper end face of the lower barrel is smooth and flat; s5, the upper barrel body and the lower barrel body are assembled and subjected to spot welding; s6, welding machine guide rails are installed; s7, a welding machine trolley is adopted for conducting circumferential weld joint welding on the upper barrel and the lower barrel; s8, the cylinder is subjected to size stabilization heat treatment; s9, the inner diameter and the outer diameter of the barrel are machined to the final size; s10, liquid penetration inspection is conducted on the surface of the weld joint; and S11, performing ray detection on the welding seam. The problems that welding of circumferential welds of medium and large barrels depends on special machines, and the quality of the welds is unstable are solved, the welding machine trolley is matched with the guide rails, automatic welding of the circumferential welds of the hanging basket barrels is achieved, and the welding efficiency and quality can be effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of nuclear reactor technology, specifically relating to a suspended basket cylinder device for a nuclear reactor and its welding method. Background Technology

[0002] The reactor core, often referred to as the "heart of the reactor," is a crucial component of a pressurized water reactor (PWR). It primarily supports the reactor core, positions fuel assemblies, and attenuates neutron radiation. It is a cylindrical stainless steel structure approximately 15 meters high and 4 meters in outer diameter, composed of an upper cylinder, lower cylinder, and base plate. Made of austenitic stainless steel, it possesses high strength, corrosion resistance, and radiation resistance. The manufacturing of the core involves sheet metal rolling, welding, and precision machining. Due to the high precision requirements, specialized machines are currently used for welding and machining. These specialized machines are equipped with a load-bearing turntable to ensure assembly accuracy, and the welding speed is controlled by the turntable's rotation.

[0003] Patent document CN109623186A discloses an assembly device for a cylinder and a cylinder body, and a cylinder body and a head. The assembly device includes: a lifting mechanism, a welding robot, an inner support fixture, and an outer clamping fixture. The lifting mechanism is positioned above the inner support fixture and lifts the lower cylinder body or the assembly component to be assembled. The inner support fixture is used to fix the lower cylinder body and the assembly component to be assembled and drive them to rotate. The inner support fixture is equipped with a lifting guide mechanism that extends upwards from the inside of the lower cylinder body to guide the descent of the upper cylinder body and to round the upper and lower cylinder bodies. The outer clamping fixture is fitted outside the inner support fixture to guide the descent of the head and clamp the outer walls of the lower cylinder body and the head. The welding robot is positioned on one side of the inner support fixture and welds the circumferential weld between the lower cylinder body and the assembly component to be assembled.

[0004] Patent document CN109623186A employs a typical technical approach, utilizing a large, specialized machine integrating load-bearing, rotation, and guiding functions to ensure welding precision. However, this type of specialized machine solution still faces limitations in adaptability and process when practically applied to the manufacture of nuclear reactor basket bodies. This type of machine often can only weld one type of basket, requiring multiple sets for multiple projects, resulting in significant space and resource consumption. Furthermore, the need for repeated modifications and reuse of these machines leads to low overall automation, unstable welding quality, low efficiency, and difficulty in guaranteeing weld quality.

[0005] To address the challenges of relying on specialized machines and inconsistent weld quality in welding circumferential welds of medium and large-sized reactor cylinders, this invention proposes a new fully automated welding method for nuclear reactor cylinders using a welding machine trolley and guide rails. This method significantly improves welding efficiency and quality. Therefore, this invention designs a nuclear reactor cylinder suspension device and its welding method, resolving the aforementioned problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a suspended basket device for nuclear reactors and its welding method.

[0007] According to the present invention, a welding method for a suspended basket assembly for a nuclear reactor includes the following steps: Step S1: Spot weld the bottom plate to the lower cylinder; Step S2: Install welding machine guide rail 1; Step S3: Use welding machine carriage 1 to weld the circumferential weld between the bottom plate and the lower cylinder; Step S4: Smooth the upper surface of the lower cylinder; Step S5: Assemble and spot weld the upper cylinder and the lower cylinder together; Step S6: Install welding machine guide rail 2 and welding machine guide rail 3; Step S7: Use welding machine carriage 2 and welding machine carriage 3 to perform circumferential welds on the upper and lower cylinders; Step S8: Perform dimensional stabilization heat treatment on the cylinder; Step S9: Machin the inner and outer diameters of the cylinder to the final dimensions.

[0008] Preferably, in step S1: argon arc welding is used for evenly distributed spot welding to control the assembly gap to 0-0.5mm; In step S4: the upper end surface of the lower cylinder is smoothed to ensure the assembly accuracy with the upper cylinder and the assembly gap is controlled to be 0-0.5mm; In step S6: the welding machine guide rail 2 is located outside the circumferential weld between the upper cylinder and the lower cylinder, and the welding machine guide rail 3 is located inside the circumferential weld between the upper cylinder and the lower cylinder. In step S8: dimensional stabilization heat treatment removes stress; In step S9: the thickness allowance of the cylinder and bottom plate is removed to the final size.

[0009] Preferably, in step S2: the welding machine guide rails 1 are distributed around the circumferential weld between the base plate and the lower cylinder, and a level is used for leveling during installation; the operation steps include: Step S2-1: Place the high-precision electronic level or bubble level on the straight reference surface of the guide rail; Step S2-2: Move the level along the length of the guide rail and observe the bubble position or digital reading at each point; Step S2-3: If tilting is found, make fine adjustments by adjusting the adjustable screws or shims of the guide rail support feet until the levelness error is within the allowable range along the entire length of the guide rail.

[0010] Preferably, in step S3: the circumferential weld between the bottom plate and the lower cylinder has a single-sided U-shaped bevel; the welding position is horizontally welded, and the welding steps include: Step S3-1: Weld shrinkage measuring blocks at four positions on the upper and lower sides of the weld: 0°, 90°, 180°, and 270°, with two blocks at each position; Step S3-2: Assemble a double-layer nozzle and a tungsten electrode of matching length on the welding machine carriage 1; Step S3-3: Adjust the welding torch of the welding machine carriage 1 to align with the center of the weld; Step S3-4: Control the welding machine carriage 1 to move at a constant speed on the welding machine guide rail 1 for one revolution, and start welding the first layer clockwise from 0°. Step S3-5: Welding trolley 1 starts the second layer by welding counterclockwise from 180° arc. Step S3-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block; Step S3-7: Select the arc initiation position according to the shrinkage amount and weld the third layer; Step S3-8: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth layer of weld; Step S3-9: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located on the upper side of the weld, and weld the upper side of the fourth layer of weld. Repeat steps S3-8 and S3-9; Step S3-10: When the weld thickness is 1 / 3, remove the inner nozzle, replace it with a tungsten electrode of matching length, and fill the weld to the last layer; Step S3-11: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located from the lower side to the upper side of the weld, and weld the last layer of 5 welds in sequence.

[0011] Preferably, in step S3-2: the double-layer nozzle includes an inner nozzle and an outer nozzle, and the nozzle structure of the inner nozzle and the outer nozzle is nearly elliptical; the inner nozzle is slender and suitable for welding the root pass; the outer nozzle is suitable for welding the fill pass. The dimensions of the double-layer nozzle structure include: the outer nozzle length is a1, the outer nozzle width is b1, and the outer nozzle rounding is R1; the inner nozzle length is a2, the inner nozzle width is b2, and the inner nozzle rounding is R2; the above dimensions must match the bevel dimensions, including: bevel depth is a, (a1+a2)≥a, generally a1≥(a / 3), a2≥(2a / 3); R2≤R; R1≤(b / 2); b2≥(10R2), b1≥(10R1).

[0012] Preferably, in steps S3-6 to S3-11: the shrinkage measuring block is used to measure the shrinkage of the weld in the height direction of the cylinder, and the arc initiation position is determined based on the shrinkage. Deformation control during welding is performed using the principle of welding reverse deformation. The steps include: Step S3-6-1: Before welding, measure the distance between the vertical shrinkage measuring blocks at four positions: 0°, 90°, 180°, and 270°, and use them as reference values; Step S3-6-2: After each weld layer is welded, measure the distance between the upper and lower shrinkage measuring blocks at four positions, compare it with the value in step S3-6-1, and mark the position with the largest shrinkage among the four positions of 0°, 90°, 180°, and 270°; Step S3-6-3: Adjust the arc starting position to be 180° away from the position with the maximum shrinkage, and perform full-circle welding.

[0013] Preferably, in step S7: the circumferential weld between the upper and lower cylinders has a double-sided U-shaped bevel, and the welding position is horizontally welded. The specific welding steps are as follows: Step S7-1: Weld shrinkage measuring blocks at four positions on the upper and lower sides of the weld: 0°, 90°, 180°, and 270°, with two blocks at each position; Step S7-2: Assemble double-layer nozzles and tungsten electrodes of matching length on welding machine carriage 2 and welding machine carriage 3; Step S7-3: Adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to align with the center of the weld; Step S7-4: Welding machine carriage 2 starts from 0° and welds the first outer layer clockwise; Step S7-5: Welding trolley 3 starts welding the first inner layer counterclockwise from 180° arc. Step S7-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block; select the arc starting position based on the shrinkage amount, and alternately weld inside and outside the welding machine carriages 2 and 3 until the third layer is reached; Step S7-7: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 2 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth outer layer weld of welding machine carriage 2; select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 2 to be located on the upper side of the weld, and weld the upper side weld bead of the fourth outer layer weld of welding machine carriage 2. Steps S7-8: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 3 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth outer layer weld of welding machine carriage 3; select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 3 to be located on the upper side of the weld, and weld the upper side weld bead of the fourth outer layer weld of welding machine carriage 3. Repeat steps S7-7 and S7-8; Steps S7-9: Welding machine carriage 2 and welding machine carriage 3 alternately weld inside and outside until 1 / 3 of the weld thickness on the matching side is reached. Then, remove the inner nozzle, replace the tungsten electrode with the matching length, and fill the weld to the last layer. Step S7-10: Select the arc starting position according to the shrinkage amount, adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to be located from the lower side to the upper side of the weld, and weld the last layer of welds on the inner and outer sides in sequence.

[0014] Preferably, in steps S3 to S7, the welding method used includes: TIG welding, MIG welding, arc welding, laser welding, and electron beam welding.

[0015] Preferably, the steps further include: Step S10: Liquid penetration test on weld surface; Step S11: Weld radiographic inspection.

[0016] According to the present invention, a suspended basket cylinder device for a nuclear reactor is provided, and a welding method for the suspended basket cylinder device for a nuclear reactor is provided, comprising: a base plate, a lower cylinder, an upper cylinder, a welding machine guide rail, and a welding machine trolley; The bottom plate, lower cylinder, and upper cylinder are coaxially stacked from bottom to top. The outer wall of the bottom plate is flush with the outer wall of the lower cylinder, and the inner and outer walls of the lower cylinder are flush with the inner and outer walls of the upper cylinder, respectively. The joint between the bottom plate and the lower cylinder is beveled on the outer side, and the joint between the upper cylinder and the lower cylinder is beveled on the inner and outer sides, respectively. The welding machine guide rail is fixed to the inner or outer side of the lower cylinder; the welding machine carriage is slidably connected to the welding machine guide rail, and the welding gun of the welding machine carriage is equipped with a double-layer nozzle that passes through the bevel; the double-layer nozzle includes an inner nozzle and an outer nozzle, the outer nozzle is movably connected to the welding machine carriage, and the inner nozzle is detachably snapped into the inside of the outer nozzle. The inner nozzle extends in the direction of the opening of the outer nozzle to its front, and the front opening of the inner nozzle is smaller than the front opening of the outer nozzle. Two shrinkage measuring blocks are located on the upper and lower sides of each bevel as a group. At least four groups of shrinkage measuring blocks are evenly spaced along the circumference of the lower cylinder. Each shrinkage measuring block is fixed to a matching upper cylinder, lower cylinder or bottom plate.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The use of a welding machine trolley in conjunction with a welding machine guide rail makes the welding machine trolley easy to disassemble and move, enabling all-round welding of the suspended basket cylinder and solving the problem of relying on special machines for welding the circumferential welds of medium and large cylinders.

[0018] 2. The arc-starting position is adjusted by the welding machine carriage according to the weld shrinkage. Weld shrinkage is adjusted in time during the welding process to effectively control the welding deformation of the circumferential weld of the suspended platform cylinder.

[0019] 3. By using a narrow-gap double-layer nozzle in conjunction with long and short tungsten electrodes, gas shielding of the weld is effectively achieved, improving weld quality and solving the problems of single nozzles being unsuitable and insufficient gas shielding in the welding process of narrow-gap, thick welds.

[0020] 4. The unique narrow-gap double-layer nozzle structure, with the inner and outer nozzles snapped together, is easy to disassemble and is compatible with narrow-gap bevel sizes, making it suitable for welding narrow-gap bevels of different thicknesses. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the welding between the base plate and the lower cylinder of the present invention.

[0022] Figure 2 This is a schematic diagram of the welding between the upper and lower cylinders of the present invention.

[0023] Figure 3 This is a schematic diagram of the welding bevel of the present invention.

[0024] Figure 4 yes Figure 3 Enlarged view of the L section.

[0025] Figure 5 yes Figure 3 Enlarged view of part M.

[0026] Figure 6 This is a schematic diagram of the narrow-gap double-layer nozzle of the present invention.

[0027] Figure 7 This is a schematic diagram of the narrow-gap double-layer nozzle of the present invention.

[0028] Figure 8 This is a schematic diagram illustrating the weld dimensions of this invention.

[0029] Figure 9 This is a schematic diagram of the welding torch position on the welding machine carriage 1 of the present invention.

[0030] Figure 10 This is a schematic diagram of the weld distribution between the base plate and the lower cylinder of the present invention.

[0031] Figure 11This is a schematic diagram of the weld distribution between the upper and lower cylinders of the present invention. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0033] like Figures 1-7 As shown, a welding method for a suspended basket assembly for a nuclear reactor includes the following steps: Step S1: Assemble and spot weld the bottom plate to the lower cylinder.

[0034] Step S2: Install welding machine guide rail 1.

[0035] Step S3: Use welding machine carriage 1 to weld the circumferential weld between the bottom plate and the lower cylinder.

[0036] Step S4: Smooth the upper surface of the lower cylinder.

[0037] Step S5: Assemble and spot weld the upper cylinder and the lower cylinder together.

[0038] Step S6: Install welding machine guide rail 2 and welding machine guide rail 3.

[0039] Step S7: Use welding machine carriage 2 and welding machine carriage 3 to perform circumferential welding of the upper and lower cylinders.

[0040] Step S8: Perform dimensional stabilization heat treatment on the cylinder.

[0041] Step S9: Machin the inner and outer diameters of the cylinder to the final dimensions.

[0042] Step S10: Liquid penetration test on weld surface.

[0043] Step S11: Weld radiographic inspection.

[0044] In step S1, argon arc welding is used to evenly distribute spot welding, and the assembly gap is controlled to be 0-0.5mm.

[0045] In step S2: the welding machine guide rails 1 are distributed around the circumferential weld between the base plate and the lower cylinder. A level is used during installation to ensure leveling and smooth movement of the welding machine trolley 1. Specific operating steps include: Step S2-1: Place the high-precision electronic level or bubble level on the straight reference surface of the guide rail.

[0046] Step S2-2: Move the level along the length of the guide rail and observe the bubble position or digital reading at each point.

[0047] Step S2-3: If tilting is found, make fine adjustments by adjusting the adjustable screws (or shims) of the guide rail support feet until the levelness error is within the allowable range (usually required to be ≤0.05mm / m) along the entire length of the guide rail.

[0048] In step S3: the circumferential weld between the bottom plate and the lower cylinder, such as... Figure 1 As shown. The bevel is a single-sided narrow-gap U-shaped bevel, as... Figure 3 As shown. The welding position is horizontally welded, and the welding steps include: Step S3-1: Weld shrinkage measuring blocks at four positions (0°, 90°, 180°, and 270°) on the upper and lower sides of the weld, two blocks at each position, as shown below. Figure 1 As shown.

[0049] Step S3-2: Assemble a narrow-gap double-layer nozzle and a long tungsten electrode on the welding machine carriage 1. The narrow-gap double-layer nozzle is as follows: Figure 4 As shown.

[0050] Step S3-3: Adjust the welding torch on the welding machine carriage 1 to align with the center of the weld, such as... Figure 5 As shown.

[0051] Step S3-4: Control the welding machine carriage 1 to move at a constant speed on the welding machine guide rail 1 for one revolution, and start welding the first layer clockwise from 0°.

[0052] Step S3-5: Welding trolley 1 starts the arc at 180° and welds the second layer counterclockwise.

[0053] Step S3-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block.

[0054] Step S3-7: Select the arc initiation position according to the shrinkage amount and weld the third layer.

[0055] Step S3-8: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth layer of weld, such as... Figure 6 As shown.

[0056] Step S3-9: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be on the upper side of the weld, and weld the upper side of the fourth layer of weld, such as... Figure 6 As shown.

[0057] Repeat steps S3-8 and S3-9.

[0058] Step S3-10: When the weld thickness is 1 / 3, remove the inner nozzle, replace the short tungsten electrode, and fill the weld to the last layer.

[0059] Step S3-11: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be located from the lower side to the upper side of the weld, and weld the last layer of 5 welds in sequence, such as... Figure 6 As shown.

[0060] In step S3-2: the double-layer nozzle mainly consists of an outer nozzle and an inner nozzle, both with nearly elliptical nozzle surfaces. Because the bottom of the narrow-gap groove is deep and narrow, larger nozzles have poor reachability and insufficient protection. The inner nozzle of this structure is slender and suitable for the root pass in narrow-gap welding, providing adequate protection for the root pass. Because the narrow-gap groove gradually widens in the upper part, the fill pass also widens due to changes in welding parameters. Narrow nozzles cannot provide sufficient protection. The outer nozzle of this structure is wide and suitable for the fill pass in narrow-gap welding.

[0061] The dimensions of the double-layer nozzle structure include: the outer nozzle length is a1, the outer nozzle width is b1, and the outer nozzle rounding is R1. The inner nozzle length is a2, the inner nozzle width is b2, and the inner nozzle rounding is R2. These dimensions must be matched with the narrow-gap bevel dimensions, including: bevel depth a, (a1+a2)≥a, generally a1≥(a / 3), a2≥(2a / 3), R2≤R, R1≤(b / 2), b2≥(10R2), b1≥(10R1).

[0062] In steps S3-6 to S3-11: the shrinkage measuring block is mainly used to measure the shrinkage of the weld in the height direction of the cylinder, determine the arc initiation position based on the shrinkage, and control deformation during the welding process using the principle of welding reverse deformation. The steps include: Step S3-6-1: Before welding, measure the distance between the vertical shrinkage measuring blocks at four positions: 0°, 90°, 180°, and 270°, and use them as reference values.

[0063] Step S3-6-2: After each weld layer is welded, measure the distance between the upper and lower shrinkage measuring blocks at four positions, compare it with the value in step S3-6-1, and mark the position with the largest shrinkage among the four positions of 0°, 90°, 180°, and 270°.

[0064] Step S3-6-3: Adjust the arc starting position to be 180° away from the position with the maximum shrinkage, and perform full-circle welding.

[0065] In step S4: the upper end surface of the lower cylinder is smoothed to ensure the assembly accuracy with the upper cylinder and the assembly gap is controlled to be 0-0.5mm.

[0066] In step S6: the welding machine guide rail 2 is located outside the circumferential weld between the upper and lower cylinders, and the welding machine guide rail 3 is located inside the circumferential weld between the upper and lower cylinders.

[0067] In step S7: the circumferential weld between the upper and lower cylinders has a double-sided narrow-gap U-shaped bevel, and the welding position is horizontally welded, such as... Figure 2 As shown, the specific welding steps are as follows: Step S7-1: Weld shrinkage measuring blocks at four positions (0°, 90°, 180°, and 270°) on the upper and lower sides of the weld, two blocks at each position, as shown below. Figure 2 As shown.

[0068] Step S7-2: Assemble a narrow-gap double-layer nozzle and a long tungsten electrode on welding machine carriage 2 and welding machine carriage 3. The narrow-gap double-layer nozzle is as follows: Figure 4 As shown.

[0069] Step S7-3: Adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to align with the center of the weld.

[0070] Step S7-4: Welding machine carriage 2 starts from 0° and welds the first outer layer clockwise.

[0071] Step S7-5: Welding machine carriage 3 starts from 180° and welds the first inner layer counterclockwise.

[0072] Step S7-6: Measure the shrinkage at 0°, 90°, 180°, and 270° using the shrinkage measuring block. Select the arc starting position based on the shrinkage amount, and alternately weld inside and outside the welding machine carriages 2 and 3 until the third layer is reached.

[0073] Step S7-7: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 2 to be located on the lower side of the weld seam, and weld the lower side weld bead of the fourth outer layer weld seam on the outer side. Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 2 to be located on the upper side of the weld seam, and weld the upper side weld bead of the fourth outer layer weld seam on the outer side, as follows. Figure 7 As shown.

[0074] Steps S7-8: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 3 to be located on the lower side of the weld seam, and weld the lower side weld bead of the fourth outer layer of weld seam on welding machine carriage 3. Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 3 to be located on the upper side of the weld seam, and weld the upper side weld bead of the fourth outer layer of weld seam on welding machine carriage 3, such as... Figure 7 As shown.

[0075] Repeat steps S7-7 and S7-8.

[0076] Steps S7-9: Welding machine carriage 2 and welding machine carriage 3 alternately weld inside and outside until the weld thickness is 1 / 3 on the matching side. Then remove the inner nozzle, replace the short tungsten electrode, and fill the weld to the last layer.

[0077] Steps S7-10: Select the arc initiation position according to the shrinkage amount, adjust the welding torches of welding machine carriage 2 and welding machine carriage 3 to be positioned from the lower side to the upper side of the weld seam respectively, and weld the last layer of weld seams on the inner and outer sides in sequence, such as... Figure 7 As shown.

[0078] In step S8, the dimensional stabilization heat treatment is mainly for stress removal.

[0079] In step S9, the thickness allowance of the cylinder and bottom plate needs to be removed to the final size.

[0080] In steps S3 to S7: the welding method is not limited to TIG welding, and other automatic or manual filler wire welding and autofusion welding methods can be used, including MIG welding, arc welding, laser welding, electron beam welding, etc.

[0081] In a more specific embodiment: Taking the suspended platform cylinder of a nuclear reactor in a certain project as an example, the base material of the parts to be welded is austenitic stainless steel, and the welding and processing procedures are as follows: Step S1: Assemble and spot weld the bottom plate to the lower cylinder.

[0082] Step S2: Install welding machine guide rail 1.

[0083] Step S3: Use welding machine carriage 1 to weld the circumferential weld between the bottom plate and the lower cylinder.

[0084] Step S4: Smooth the upper surface of the lower cylinder.

[0085] Step S5: Assemble and spot weld the upper cylinder and the lower cylinder together.

[0086] Step S6: Install welding machine guide rail 2 and welding machine guide rail 3.

[0087] Step S7: Use welding machine carriage 2 and welding machine carriage 3 to perform circumferential welding of the upper and lower cylinders.

[0088] Step S8: Perform dimensional stabilization heat treatment on the cylinder.

[0089] Step S9: Machin the inner and outer diameters of the cylinder to the final dimensions.

[0090] Step S10: Liquid penetration test on weld surface.

[0091] Step S11: Weld radiographic inspection.

[0092] In step S1, argon arc welding is used to evenly distribute spot welding, and the assembly gap is controlled to be 0-0.5mm.

[0093] In step S2: the welding machine guide rails 1 are distributed around the circumferential weld between the base plate and the lower cylinder. A level is used during installation to ensure leveling and smooth movement of the welding machine trolley 1. Specific operating steps include: Step S2-1: Place the high-precision electronic level or bubble level on the straight reference surface of the guide rail.

[0094] Step S2-2: Move the level along the length of the guide rail and observe the bubble position or digital reading at each point.

[0095] Step S2-3: If tilting is found, make fine adjustments by adjusting the adjustable screws (or shims) of the guide rail support feet until the levelness error is ≤0.05mm / m along the entire length of the guide rail.

[0096] In step S3: the circumferential weld between the bottom plate and the lower cylinder, such as... Figure 1 As shown. The bevel is a single-sided narrow-gap U-shaped bevel, as... Figure 3 As shown. The welding position is horizontal, with a weld thickness of 48mm, a bevel rounding radius of R=5±0.5mm, a bevel angle of 10±1°, and a blunt edge of 2 (0, +0.13)mm. The welding steps include: Step S3-1: Weld shrinkage measuring blocks at four positions (0°, 90°, 180°, and 270°) on the upper and lower sides of the weld, two blocks at each position, as shown below. Figure 1 As shown.

[0097] Step S3-2: Assemble a narrow-gap double-layer nozzle and a long tungsten electrode on the welding machine carriage 1. The narrow-gap double-layer nozzle is as follows: Figure 4 As shown.

[0098] Step S3-3: Adjust the welding torch on the welding machine carriage 1 to align with the center of the weld, such as... Figure 5 As shown.

[0099] Step S3-4: Control the welding machine carriage 1 to move at a constant speed on the welding machine guide rail 1 for one revolution, and start welding the first layer clockwise from 0°.

[0100] Step S3-5: Welding trolley 1 starts the arc at 180° and welds the second layer counterclockwise.

[0101] Step S3-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block.

[0102] Step S3-7: Select the arc initiation position according to the shrinkage amount and weld the third layer.

[0103] Step S3-8: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth layer of weld, such as... Figure 6 As shown.

[0104] Step S3-9: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be on the upper side of the weld, and weld the upper side of the fourth layer of weld, such as... Figure 6 As shown.

[0105] Repeat steps S3-8 and S3-9.

[0106] Step S3-10: When the weld thickness is 1 / 3, remove the inner nozzle, replace the short tungsten electrode, and fill the weld to the last layer.

[0107] Step S3-11: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 1 to be located from the lower side to the upper side of the weld, and weld the last layer of 5 welds in sequence, such as... Figure 6 As shown.

[0108] In step S3-2, the dimensions of the double-layer nozzle structure include: the outer nozzle length is a1, the outer nozzle width is b1, and the outer nozzle rounding is R1. The inner nozzle length is a2, the inner nozzle width is b2, and the inner nozzle rounding is R2. These dimensions must be matched with the narrow gap bevel dimensions, including: The bevel depth is 'a', (a1+a2)≥a=48mm, a1≥(a / 3)=16mm, a2≥(2a / 3)=32mm. R2≤R, and R2=5mm, R=5mm. R1≤(b / 2), and R1=8mm, (b / 2)=8mm. b2≥(10R2)=50mm, b1≥(10R1)=80mm.

[0109] The welding parameters for the circumferential weld between the bottom plate and the lower cylinder are as follows: TIG root pass parameters: ER308L welding material, φ1.2mm, DC positive polarity, current 180-220A, voltage 10-13V, welding speed 8-15cm / min, wire feed speed 100-120cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0110] TIG filler welding parameters: ER308L welding material, φ1.2mm, DC positive polarity, current 250-300A, voltage 15-20V, welding speed 15-20cm / min, wire feed speed 150-200cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0111] TIG cover pass welding parameters: ER308L welding material, φ1.2mm, DC positive polarity, current 200-240A, voltage 12-15V, welding speed 15-18cm / min, wire feed speed 120-150cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0112] TIG root pass parameters are relatively small, TIG fill pass parameters are relatively large, and TIG cap pass parameters are moderate. Figure 6 As shown.

[0113] In step S4: the upper end surface of the lower cylinder is smoothed to ensure the assembly accuracy with the upper cylinder and the assembly gap is controlled to be 0-0.5mm.

[0114] In step S6: the welding machine guide rail 2 is located outside the circumferential weld between the upper and lower cylinders, and the welding machine guide rail 3 is located inside the circumferential weld between the upper and lower cylinders.

[0115] In step S7: the circumferential weld between the upper and lower cylinders has a double-sided narrow-gap U-shaped bevel, with horizontal welding at the welding position. The weld thickness is 60mm, the outer bevel depth is 35mm, the inner bevel depth is 23mm, the bevel rounding radius is R=5±0.5mm, the bevel angle is 10±1°, and the blunt edge is 2(0,+0.13)mm. Figure 2 As shown, the specific welding steps are as follows: Step S7-1: Weld shrinkage measuring blocks at four positions (0°, 90°, 180°, and 270°) on the upper and lower sides of the weld, two blocks at each position, as shown below. Figure 2 As shown.

[0116] Step S7-2: Assemble a narrow-gap double-layer nozzle and a long tungsten electrode on welding machine carriage 2 and welding machine carriage 3. The narrow-gap double-layer nozzle is as follows: Figure 4 As shown.

[0117] Step S7-3: Adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to align with the center of the weld.

[0118] Step S7-4: Welding machine carriage 2 starts from 0° and welds the first outer layer clockwise.

[0119] Step S7-5: Welding machine carriage 3 starts from 180° and welds the first inner layer counterclockwise.

[0120] Step S7-6: Measure the shrinkage at 0°, 90°, 180°, and 270° using the shrinkage measuring block. Select the arc starting position based on the shrinkage amount, and alternately weld inside and outside the welding machine carriages 2 and 3 until the third layer is reached.

[0121] Step S7-7: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 2 to be located on the lower side of the weld seam, and weld the lower side weld bead of the fourth outer layer weld seam on the outer side. Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 2 to be located on the upper side of the weld seam, and weld the upper side weld bead of the fourth outer layer weld seam on the outer side, as follows. Figure 7 As shown.

[0122] Steps S7-8: Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 3 to be located on the lower side of the weld seam, and weld the lower side weld bead of the fourth outer layer of weld seam on welding machine carriage 3. Select the arc initiation position according to the shrinkage amount, adjust the welding torch of welding machine carriage 3 to be located on the upper side of the weld seam, and weld the upper side weld bead of the fourth outer layer of weld seam on welding machine carriage 3, such as... Figure 7 As shown.

[0123] Repeat steps S7-7 and S7-8.

[0124] Steps S7-9: Welding machine carriage 2 and welding machine carriage 3 alternately weld inside and outside until the weld thickness is 1 / 3 on the matching side. Then remove the inner nozzle, replace the short tungsten electrode, and fill the weld to the last layer.

[0125] Steps S7-10: Select the arc initiation position according to the shrinkage amount, adjust the welding torches of welding machine carriage 2 and welding machine carriage 3 to be positioned from the lower side to the upper side of the weld seam respectively, and weld the last layer of weld seams on the inner and outer sides in sequence, such as... Figure 7 As shown.

[0126] The welding parameters for the circumferential weld between the upper and lower cylinders are as follows: TIG root pass parameters: ER308L welding material, φ1.2mm, DC positive polarity, current 180-210A, voltage 10-12V, welding speed 8-14cm / min, wire feed speed 100-120cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0127] TIG filler welding parameters: ER308L welding material, φ1.2mm, DC positive polarity, current 240-300A, voltage 14-20V, welding speed 16-20cm / min, wire feed speed 150-200cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0128] TIG cover pass welding parameters: welding material ER308L, φ1.2mm, DC positive polarity, current 200-220A, voltage 12-14V, welding speed 15-18cm / min, wire feed speed 120-150cm / min, 70%He+30%Ar mixed gas, flow rate 20-30L / min.

[0129] In step S8: dimensional stabilization heat treatment: 410±10℃, not less than 24h, mainly to remove stress.

[0130] In step S9, the thickness allowance of the cylinder and bottom plate needs to be removed to the final size.

[0131] In step S10: the liquid penetration test of the weld surface is carried out in accordance with NB 47013.5-15, and the acceptance is based on the first-class weld. The liquid penetration test is qualified.

[0132] In step S11: the weld is inspected by radiographic testing according to NB 47013.2-15, and the acceptance is based on the first-class weld, and the radiographic testing is qualified.

[0133] The advantages of this embodiment are as follows: The use of a welding machine carriage with a welding machine guide rail facilitates the disassembly and movement of the carriage, enabling omnidirectional welding of the suspended platform cylinder and solving the problem of relying on dedicated machines for welding circumferential welds of medium and large cylinders. The welding machine carriage adjusts the arc initiation position according to the weld shrinkage, and timely adjustments are made during the welding process to effectively control welding deformation of the suspended platform cylinder's circumferential welds. The use of a narrow-gap double-layer nozzle with long and short tungsten electrodes effectively achieves gas shielding for the weld, improving weld quality and solving the problems of single nozzles being unsuitable and insufficient gas shielding in the welding of narrow-gap, thick welds. The originality of the narrow-gap double-layer nozzle structure, with its interlocking combination of inner and outer nozzles, facilitates disassembly and is compatible with narrow-gap bevel dimensions, making it suitable for welding narrow-gap bevels of varying thicknesses.

[0134] This application also provides a suspended basket body device for nuclear reactors, and a welding method for a suspended basket body device for nuclear reactors, comprising: a base plate, a lower cylinder, an upper cylinder, a shrinkage measuring block, a welding machine guide rail, and a welding machine trolley.

[0135] The bottom plate, lower cylinder, and upper cylinder are coaxially stacked from bottom to top. The outer wall of the bottom plate is flush with the outer wall of the lower cylinder, and the inner and outer walls of the lower cylinder are flush with the inner and outer walls of the upper cylinder, respectively.

[0136] The joint between the bottom plate and the lower cylinder has a bevel on the outer side, while the joint between the upper cylinder and the lower cylinder has bevels on both the inner and outer sides.

[0137] The welding machine guide rail is fixed to the inner or outer side of the lower cylinder; the welding machine carriage is slidably connected to the welding machine guide rail, and the welding gun of the welding machine carriage is equipped with a double-layer nozzle that passes through the bevel.

[0138] The double-layer nozzle includes an inner nozzle and an outer nozzle. The outer nozzle is movably connected to the welding machine carriage, and the inner nozzle is detachably snapped into the inside of the outer nozzle. The inner nozzle extends in front of the outer nozzle opening, and the front opening of the inner nozzle is smaller than the front opening of the outer nozzle.

[0139] Two shrinkage measuring blocks are located on the upper and lower sides of each bevel as a group. At least four groups of shrinkage measuring blocks are evenly spaced along the circumference of the lower cylinder. Each shrinkage measuring block is fixed to a matching upper cylinder, lower cylinder or bottom plate.

[0140] A welding machine track 1 is installed on the outer side of the joint between the upper cylinder and the base, and a welding machine carriage 1 is installed on the welding machine track 1. A welding machine track 2 is installed on the outer side of the joint between the upper cylinder and the lower cylinder, and a welding machine carriage 2 is installed on the welding machine track 2. A welding machine track 3 is installed on the inner side of the joint between the upper cylinder and the lower cylinder, and a welding machine carriage 3 is installed on the welding machine track 3.

[0141] In one embodiment, the welding machine track is an adjustable radial support mechanism, which includes a support frame, support arms, extension rods, and a track bracket. The support frame is housed in the lower cylinder and abuts against the base plate. At least three support arms extend horizontally outward from a point on the support frame, and the extension ends of the support arms are mechanically or hydraulically adjustable in length. The extension rods are fixed to the support frame. The track brackets are fixed to the extension rods.

[0142] In one embodiment, the welding machine track is an adjustable radial support mechanism, which includes a support frame, support arms, extension rods, and a track bracket. The support frame is fitted onto the lower cylinder and abuts against the base plate. At least three support arms extend horizontally inward from a point on the support frame, and the extension ends of the support arms are mechanically or hydraulically adjustable in length. The extension rods are fixed to the support frame. The track brackets are fixed to the extension rods.

[0143] The adjustable radial support mechanism works by using the cylinder's own structure to forcibly establish a standard center with the inner or outer wall of the cylinder as a reference, and then rigidly connecting the welding machine trolley track to this reference or calibrating it with laser linkage.

[0144] The positioning method for the adjustable radial support mechanism includes the following specific steps: Step S1: Establish an internal rigid reference (internal support centering method) and install a radially expandable "central support frame" inside the cylinder.

[0145] Step S2: Place the central support frame inside the cylinder joint and adjust the support arm outward by mechanical screw or hydraulic means to make it evenly contact the inner wall. At this time, the central axis of the support frame is the ideal axis of the cylinder.

[0146] Step S3: Fix the rail bracket of the welding machine trolley directly to the extension rod of this internal support frame, or lock the rail to the internal support frame through a rigid connecting rod.

[0147] The track is forced to be coaxial with the internal reference of the cylinder, so that the welding machine trolley will not deviate due to unevenness of the external weld seam during operation.

[0148] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0149] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A welding method for a suspended basket cylinder assembly for a nuclear reactor, characterized in that the steps include... include: Step S1: Spot weld the bottom plate to the lower cylinder; Step S2: Install welding machine guide rail 1; Step S3: Use welding machine carriage 1 to weld the circumferential weld between the bottom plate and the lower cylinder; Step S4: Smooth the upper surface of the lower cylinder; Step S5: Spot weld the upper cylinder and the lower cylinder together; Step S6: Install welding machine guide rail 2 and welding machine guide rail 3; Step S7: Use welding machine carriage 2 and welding machine carriage 3 to perform circumferential welding of the upper and lower cylinders; Step S8: Perform dimensional stabilization heat treatment on the cylinder; Step S9: Machin the inner and outer diameters of the cylinder to the final dimensions.

2. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 1, characterized in that, In step S1: Argon arc welding is used to evenly distribute spot welding, and the assembly gap is controlled to be 0-0.5mm; In step S4: the upper end surface of the lower cylinder is smoothed to ensure the assembly accuracy with the upper cylinder and the assembly gap is controlled to be 0-0.5mm; In step S6: the welding machine guide rail 2 is located outside the circumferential weld between the upper cylinder and the lower cylinder, and the welding machine guide rail 3 is located inside the circumferential weld between the upper cylinder and the lower cylinder. In step S8: dimensional stabilization heat treatment removes stress; In step S9: the thickness allowance of the cylinder and bottom plate is removed to the final size.

3. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 1, characterized in that, In step S2: the welding machine guide rails 1 are distributed around the circumferential weld between the base plate and the lower cylinder, and a level is used for leveling during installation; the operation steps include: Step S2-1: Place the high-precision electronic level or bubble level on the straight reference surface of the guide rail; Step S2-2: Move the level along the length of the guide rail and observe the bubble position or digital reading at each point; Step S2-3: If tilting is found, make fine adjustments by adjusting the adjustable screws or shims of the guide rail support feet until the levelness error is within the allowable range along the entire length of the guide rail.

4. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 1, characterized in that, In step S3: the circumferential weld between the bottom plate and the lower cylinder has a single-sided U-shaped bevel. The welding position is horizontally welded, and the welding steps include: Step S3-1: Weld shrinkage measuring blocks at four positions on the upper and lower sides of the weld: 0°, 90°, 180°, and 270°, with two blocks at each position; Step S3-2: Assemble a double-layer nozzle and a tungsten electrode of matching length on the welding machine carriage 1; Step S3-3: Adjust the welding torch of the welding machine carriage 1 to align with the center of the weld; Step S3-4: Control the welding machine carriage 1 to move at a constant speed on the welding machine guide rail 1 for one revolution, and start welding the first layer clockwise from 0°. Step S3-5: Welding trolley 1 starts the second layer by welding counterclockwise from 180° arc. Step S3-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block; Step S3-7: Select the arc initiation position according to the shrinkage amount and weld the third layer; Step S3-8: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth layer of weld; Step S3-9: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located on the upper side of the weld, and weld the upper side of the fourth layer of weld. Repeat steps S3-8 and S3-9; Step S3-10: When the weld thickness is 1 / 3, remove the inner nozzle, replace it with a tungsten electrode of matching length, and fill the weld to the last layer; Step S3-11: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 1 to be located from the lower side to the upper side of the weld, and weld the last layer of 5 welds in sequence.

5. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 4, characterized in that, In step S3-2: the double-layer nozzle includes an inner nozzle and an outer nozzle, and the nozzle structure of the inner nozzle and the outer nozzle is nearly elliptical; the inner nozzle is slender and suitable for welding the root pass; the outer nozzle is suitable for welding the fill pass. The dimensions of the double-layer nozzle structure include: the outer nozzle length is a1, the outer nozzle width is b1, and the outer nozzle rounding is R1; the inner nozzle length is a2, the inner nozzle width is b2, and the inner nozzle rounding is R2; the above dimensions must match the bevel dimensions, including: bevel depth is a, (a1+a2)≥a, a1≥(a / 3), a2≥(2a / 3); R2≤R; R1≤(b / 2); b2≥(10R2), b1≥(10R1).

6. The welding method for the suspended basket body device for a nuclear reactor according to claim 4, characterized in that, In steps S3-6 to S3-11: the shrinkage measuring block is used to measure the shrinkage of the weld in the height direction of the cylinder, and the arc initiation position is determined based on the shrinkage. The deformation is controlled during the welding process using the principle of welding reverse deformation. The steps include: Step S3-6-1: Before welding, measure the distance between the vertical shrinkage measuring blocks at four positions: 0°, 90°, 180°, and 270°, and use them as reference values; Step S3-6-2: After each weld layer is welded, measure the distance between the upper and lower shrinkage measuring blocks at four positions, compare it with the value in step S3-6-1, and mark the position with the largest shrinkage among the four positions of 0°, 90°, 180°, and 270°. Step S3-6-3: Adjust the arc starting position to be 180° away from the position with the maximum shrinkage, and perform full-circle welding.

7. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 1, characterized in that, In step S7: the circumferential weld between the upper and lower cylinders has a double-sided U-shaped bevel, and the welding position is horizontal. The specific welding steps are as follows: Step S7-1: Weld shrinkage measuring blocks at four positions on the upper and lower sides of the weld: 0°, 90°, 180°, and 270°, with two blocks at each position; Step S7-2: Assemble double-layer nozzles and tungsten electrodes of matching length on welding machine carriage 2 and welding machine carriage 3; Step S7-3: Adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to align with the center of the weld; Step S7-4: Welding machine carriage 2 starts from 0° and welds the first outer layer clockwise; Step S7-5: Welding trolley 3 starts welding the first inner layer counterclockwise from 180° arc. Step S7-6: Measure the shrinkage at 0°, 90°, 180°, and 270° positions using the shrinkage measuring block; select the arc starting position based on the shrinkage amount, and alternately weld inside and outside the welding machine carriages 2 and 3 until the third layer is reached; Step S7-7: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 2 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth outer layer weld of welding machine carriage 2; select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 2 to be located on the upper side of the weld, and weld the upper side weld bead of the fourth outer layer weld of welding machine carriage 2. Steps S7-8: Select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 3 to be located on the lower side of the weld, and weld the lower side weld bead of the fourth outer layer weld of welding machine carriage 3; select the arc starting position according to the shrinkage amount, adjust the welding gun of welding machine carriage 3 to be located on the upper side of the weld, and weld the upper side weld bead of the fourth outer layer weld of welding machine carriage 3. Repeat steps S7-7 and S7-8; Steps S7-9: Welding machine carriage 2 and welding machine carriage 3 alternately weld inside and outside until 1 / 3 of the weld thickness on the matching side is reached. Then, remove the inner nozzle, replace the tungsten electrode with the matching length, and fill the weld to the last layer. Step S7-10: Select the arc starting position according to the shrinkage amount, adjust the welding guns of welding machine carriage 2 and welding machine carriage 3 to be located from the lower side to the upper side of the weld, and weld the last layer of welds on the inner and outer sides in sequence.

8. The welding method for the suspended basket cylinder device for nuclear reactors according to claim 1, characterized in that, In steps S3 to S7, the welding methods used include: TIG welding, MIG welding, arc welding, laser welding, and electron beam welding.

9. The welding method for the suspended basket cylinder assembly for a nuclear reactor according to claim 1, characterized in that, The steps also include: Step S10: Liquid penetration test on weld surface; Step S11: Weld radiographic inspection.

10. A suspended basket assembly for a nuclear reactor, used in the welding method of the suspended basket assembly for a nuclear reactor as described in any one of claims 1-9, characterized in that, include: Base plate, lower cylinder, upper cylinder, welding machine guide rail and welding machine trolley; The bottom plate, lower cylinder, and upper cylinder are coaxially stacked from bottom to top. The outer wall of the bottom plate is flush with the outer wall of the lower cylinder, and the inner and outer walls of the lower cylinder are flush with the inner and outer walls of the upper cylinder, respectively. The joint between the bottom plate and the lower cylinder is beveled on the outer side, and the joint between the upper cylinder and the lower cylinder is beveled on the inner and outer sides, respectively. The welding machine guide rail is fixed to the inner or outer side of the lower cylinder; the welding machine carriage is slidably connected to the welding machine guide rail, and the welding gun of the welding machine carriage is equipped with a double-layer nozzle that passes through the bevel; the double-layer nozzle includes an inner nozzle and an outer nozzle, the outer nozzle is movably connected to the welding machine carriage, and the inner nozzle is detachably snapped into the inside of the outer nozzle. The inner nozzle extends in the direction of the opening of the outer nozzle to its front, and the front opening of the inner nozzle is smaller than the front opening of the outer nozzle. Two shrinkage measuring blocks are located on the upper and lower sides of each bevel as a group. At least four groups of shrinkage measuring blocks are evenly spaced along the circumference of the lower cylinder. Each shrinkage measuring block is fixed to a matching upper cylinder, lower cylinder or bottom plate.

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