CN115846827A - Thin shell type semispherical dome structure of nuclear power station containment vessel steel lining and manufacturing method thereof - Google Patents

Abstract

The invention discloses a thin-shell type semispherical dome structure of a nuclear power station containment vessel steel lining and a manufacturing method thereof.A dome partition plate is formed by welding unit plates in a splicing manner, nuclear-grade anticorrosive paint is brushed on the inner side of the partition plate, and transverse and longitudinal stiffening and anchoring nails are welded on the outer side of the partition plate; after the block plates are prefabricated in a workshop, the block plates are assembled into a whole on site, and finally, large-scale hoisting equipment is adopted to integrally hoist and position the block plates. The invention adopts key technologies of optimizing plate parting, forming die, adding stiffening ribs, curved surface submerged arc welding and the like, and solves the problems of difficult radian molding, difficult deformation control and high requirement on dimensional precision; the unit plate splicing submerged arc welding technology, the block plate mould one-step forming technology and the large-breadth block plate splicing technology are adopted, the construction period is shortened, the cost is saved, and the integral construction progress of the steel lining dome is ensured. The invention has the advantages of high forming quality, small welding deformation, high construction efficiency and reduced on-site assembling quantity.

Description

Thin-shell type semispherical dome structure of steel lining of nuclear power station containment vessel and manufacturing method thereof

Technical Field

The invention belongs to the technical field of building construction, and relates to a forming tool, a forming method and deformation control for manufacturing a hemispherical dome of a nuclear island steel lining, in particular to a thin shell type hemispherical dome structure of a nuclear power station containment steel lining and a manufacturing method thereof.

Background

The Hualong I reactor type nuclear power station has a third-generation nuclear power technology with complete independent intellectual property rights, a nuclear island steel lining has the main function of resisting nuclear pollution diffusion under the working condition of an abnormal accident, is a third leakage-proof barrier of the nuclear power station, and a dome is used as a capping part of a containment steel lining and has the same function. The Hualong I-shaped steel-lined dome is composed of a P265GH 6mm thick steel plate, L200X 125X 12 and L75X 50X 6 angle steel stiffening ribs and welding nails which are welded on the outer side, a workshop is prefabricated into 62 block plates, the block plates are welded on the spot, the appearance of the dome is a hemispherical shell with the inner side diameter of 46.8m, and the dome is nuclear safety related equipment with quality assurance grade QA1 and nuclear safety grade 2.

Compared with the CPR1000, WWER-1000 and EPR reactor types at present in China, the steel-lined dome with the 'Hualong I' is the giant hemispherical dome which has the largest body type and the highest total amount in the nuclear power station up to now and has the most remarkable difference in the size. The new pile type "hualong one" has no mature construction experience and can be adopted.

At present, dome manufacture at home and abroad mostly adopts the manual welding process of slice pressing forming and moulding assembly. A plate rolling machine rolling forming process is adopted for manufacturing the dome of Yangjiang second-stage CPR1000, and a submerged arc welding process is introduced to carry out shell plate splicing on the basis of the Taishan EPR pile type. The method is not realized, the process of direct molding of the forming die and automatic submerged arc welding and assembly of the shell plate is used for the manufacturing technology of the hemispherical dome, and the manufacturing of the containment dome of the Bakistan kalazar K-2/K-3 nuclear power project is initiated at home and abroad.

Disclosure of Invention

The invention aims to solve the technical problems that a partitioning plate of a steel lining shell type semispherical dome of a nuclear power station containment vessel is large in size, difficult in radian forming, difficult in deformation control, high in size precision requirement and the like, and provides a steel lining shell type semispherical dome structure of a nuclear power station containment vessel and a manufacturing method thereof.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a manufacturing method of a lamella type semispherical dome structure of a containment vessel steel lining of a nuclear power station comprises the following steps:

step one, analyzing whether each layer of a dome steel lining needs to be re-partitioned, dividing the design of the dome layer needing to be re-partitioned into partitioned plates, and dividing the design of the partitioned plates into unit plates;

step two, manufacturing a forming die matched with the dome wall plate according to the size and drawing requirements of the dome layer needing to be partitioned again according to analysis design;

thirdly, blanking a unit plate meeting the size precision through a numerical control cutting machine, and automatically lofting longitudinal and transverse angle steel positioning lines on the unit plate by using a scribing device of the numerical control cutting machine;

transporting the unit plates onto a forming die, sequentially placing and splicing the unit plates into the forming die, and attaching the wall plates of the unit plates to the forming die by adopting a fixed tool;

step five, welding the unit plates on the forming die to form a block plate;

welding radian-molded longitudinal and transverse stiffening rib angle steel on the convex surface of the block plate to manufacture a dome block wall plate;

step seven, after the dome block wall plate is taken down from the moulding bed, turning 180 degrees for welding the inner side weld joint;

step eight, mounting anchoring nails on the dome block wall plate;

step nine, performing anticorrosive coating on the dome block wall plate;

step ten, assembling all dome layers into a whole on site.

In the first step, the dome steel lining is analyzed by adopting a polar cap meridian mixed spherical expansion method and a TAKELA three-dimensional model.

And in the second step, arc-shaped angle steel is added in the radial direction according to the difference of the width size of each dome layer layered plate, so that the splicing welding seam of the layered plate on the forming die is not in a suspended position, and the periphery of the layered plate is tightly attached to the forming die.

And in the fourth step, a limiting device is arranged on the outer side of the contact position of the platform where the moulding bed is placed and one end of the moulding bed, so that the moulding bed is prevented from sliding on the platform when the other end of the moulding bed is lifted.

And fifthly, welding the unit plates on the forming die by adopting submerged arc automatic welding, adjusting the welding position of the outer convex surface by adopting a forklift, and using a seesaw type leveling device when the inner concave surface is welded, so that the welding position of the unit plate splicing welding line on the forming die is always in the range of-15 degrees to +15 degrees from the horizontal plane.

And in the sixth step, after the radian-formed longitudinal and transverse stiffening rib angle steel is subjected to cold bending primary forming, the radian precision is adjusted by matching the radian control device with flame correction.

And seventhly, adopting a seesaw type leveling device to assist submerged arc automatic welding, so that the welding position of the welding seam is always in the range of-15 degrees to +15 degrees from the horizontal plane.

The seesaw type leveling device comprises a rotating shaft supporting frame and a balance weight leveling device, wherein a unit plate is placed on the rotating shaft supporting frame, the rotating shaft supporting frame is positioned in the center of the bottom of the unit plate, a clamping groove is formed in the rotating shaft supporting frame, the unit plate is fixed with the supporting frame, the balance weight leveling device is positioned on the unit plate on one side of the rotating shaft supporting frame, and a submerged arc welding machine is arranged on the unit plate on the other side of the rotating shaft supporting frame.

And step eight, taking the longitudinal and transverse stiffening rib angle steel frame on the dome block wall plate as a unit, searching for the arrangement commonality of the anchoring nails in the unit to design a common template for installing the anchoring nails, forming positioning small holes with the diameter of 5mm at the lofting positions of the anchoring nails on the template, and positioning the anchoring nails by adopting the template.

The welding process sequence of the angle steel with the six stiffening ribs is as follows: firstly welding the welding seams of the larger angle steel and the steel plate, then welding the welding seams of the rest smaller angle steel and the steel plate, and finally welding the welding seams between the angle steel, wherein 4-6 welders perform sectional back welding on two sides of the angle steel from the middle to two ends during welding; the welding direction is from the middle to the two ends; fillet welds between the stiffening ribs and the block plates are staggered welds; after the angle steel of the stiffening rib is welded, the partition plate can be removed after the partition plate is formed on the forming die for at least 24 hours.

Compared with the prior art, the invention has the beneficial effects that:

the invention relates to a semi-spherical shell structure of a steel lining of a containment vessel of a nuclear power station and a manufacturing method thereof, which adopts key technologies such as optimized plate parting, auxiliary molding of a moulding bed and a stiffening rib, stiffening rib attaching method, curved surface submerged arc welding and the like, and solves the problems of difficult radian molding, difficult deformation control and high requirement on dimensional accuracy; the unit plate splicing submerged arc welding technology, the block plate mould one-step forming technology and the large-breadth block plate splicing technology are adopted, the construction period is shortened, the cost is saved, and the integral construction progress of the steel lining dome is ensured. The invention has the advantages of high forming quality, small welding deformation, high construction efficiency and reduced on-site assembling quantity.

According to the invention, through reasonable parting and manufacturing of the special hyperboloid general tire mold, as well as the technological methods of submerged arc welding wane type tool assistance, large-breadth board dividing workshop splicing technology and the like, deformation of the block boards in the manufacturing process is effectively prevented, the dome manufacturing quality is greatly improved, and a foundation is laid for shortening the construction period and reducing the safety risk in dome splicing.

Compared with the traditional construction method, the novel process greatly improves the construction quality and the welding quality, meets the requirements on good dimensional precision, overcomes the problems of difficult radian forming, large welding deformation and long manufacturing period of the traditional block plate, provides powerful technical support for smoothly completing the field assembly and hoisting of the dome, and further provides powerful support for hoisting nuclear island equipment and nuclear fuel.

Specifically, the invention has the following characteristics:

1) According to the invention, by designing the universal moulding bed and adopting the direct forming technology of the moulding bed and the stiffening ribs, the pressing or rolling process of the unit plate is removed, the manufacturing period is shortened, and the prefabrication cost is saved;

2) The spherical unit plate determines the blanking size of the unit plate steel plate through software modeling optimization parting and lofting technology, reduces the total number of the block plates, solves the problem of solid lofting of the fan-shaped unit plate, and ensures the sheet size and spherical radius forming quality of the dome block plate;

3) By designing the sequence of the stiffening rib welding process and a rigid fixing method of additional angle steel, the welding deformation is effectively controlled, and the tolerance precision of the radian of the wall plate in the construction process is ensured;

4) The welding technology of splicing the spherical unit plates by adopting the submerged arc automatic welding process is assisted by designing a 'wane type' submerged arc tool, the submerged arc automatic welding process is used for achieving maximization, and the manufacturing quality and the construction efficiency are further improved;

5) The partial layered split plates can adopt a large-width split plate assembling technology, so that the welding seam assembling amount is reduced, the field assembling construction period is shortened, the construction operation environment is improved, and the construction safety risk is reduced.

Drawings

FIG. 1 is a schematic view of a steel lined hemispherical dome segmented panel of the present invention.

Fig. 2 is a process flow diagram for constructing a steel-lined hemispherical dome segment plate.

FIG. 3 is a schematic view of a dome tire mold.

FIG. 4 is a node diagram of the structure of the separation plate fixedly attached to the molding bed.

FIG. 5 is a schematic view of a submerged arc welding process for matching leveling of a forklift.

FIG. 6 is a schematic view of a stiffener camber control device.

Fig. 7 is a schematic view of a sample plate for arc inspection.

Fig. 8 is a schematic view of the method of adding stiffeners.

FIG. 9 is a schematic cross-welding of stiffeners.

Fig. 10 is a schematic view of a "rocker" leveling device.

FIG. 11 is a schematic view of an anchor nail lofting template.

In the figure: 1-splitting plate, 11-unit plate, 12-stiffening rib, 13-anchoring nail, 14-splicing welding line, 2-forming die, 21-arc angle steel, 22-base, 3-splitting plate fixed node diagram, 31-wedge iron, 32-U type iron, 4-forklift cooperation welding device, 41-forklift, 42-submerged arc welding machine, 43-steel plate baffle, 44-prefabricated platform, 5-stiffening rib radian control device, 51-screw jack, 52-limiting plate, 53-L type iron, 54-wedge iron, 55-steel platform, 6-additional stiffening rib method, 61-additional stiffening angle steel, 7-staggered welding line, 8-rocker type leveling device, 81-turning away supporting frame and 82-counterweight adjusting device.

Detailed description of the preferred embodiments

The present invention is described in more detail below by way of examples, but it should not be construed that the scope of the subject matter of the present invention is limited to the examples below, and that techniques realized based on the above contents of the present invention are within the scope of the present invention.

In the description of the present invention, it is also to be noted that: the positional or orientational relationships are those illustrated in the drawings for ease of description and simplicity of description, and are not intended to indicate or imply that the referenced devices or elements must be in a particular orientation, constructed and operative in a particular orientation and are not to be construed as limiting the present invention. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

The dome design of the steel lining shell type semispherical dome structure of the nuclear power station containment vessel is divided into a plurality of block plates 1 (shown in figure 1), the block plates are formed by welding unit plates 11, nuclear-grade anticorrosive paint is brushed on the inner side, and transverse and longitudinal stiffening ribs 12 and anchoring nails 13 are welded on the outer side.

The manufacturing process flow of the block plate is shown in figure 2, and mainly comprises the following steps:

analyzing a dome steel lining according to a polar cap meridian mixed spherical expansion method and a TAKELA three-dimensional model, refining and decomposing block plates when blocks are smaller and closer to an expansion value, re-blocking each layer on the premise of meeting technical standards and quality, and dividing each block plate into four unit plate curved surfaces for splicing;

and step two, manufacturing a forming die 2 (shown in figure 3) matched with the dome wall plate according to the size of the parting plate after the parting and the drawing requirements. According to the hemispherical characteristic, the moulding bed can be made into a universal moulding bed. According to the local transformation, arc-shaped angle steel is added in the radial direction according to the difference of the width and the size of each layer of block plates, so that the splicing welding seam of the block plates on the moulding bed is not in a suspended position, the periphery of the plate is tightly attached to the moulding bed, and the multi-purpose effect of one membrane is realized;

thirdly, blanking a unit plate meeting the dimensional accuracy through a numerical control cutting machine, and automatically lofting a longitudinal and transverse stiffening rib positioning line by using a scribing device of the numerical control cutting machine;

transporting the unit plates to a forming die to be sequentially placed into a split plate, adopting a fixing tool to enable the split plate to be attached to the forming die (see figure 4), welding a steel plate baffle 43 on the outer side of a contact part of one end of the forming die and a prefabricated platform 44 for limiting, and enabling the forming die not to slide on the prefabricated platform when the other end of the forming die is lifted;

welding the unit plates on the forming die by adopting a submerged arc welding machine 42 to weld and splice the welding seam 14, lifting one end of the forming die by utilizing a forklift 41, and slowly lifting the forming die in the welding process to enable the welding seam welding position of the unit plates on the forming die to be in an approximately horizontal state within a range of an included angle of-15 to +15 degrees with the horizontal plane (see figure 5);

and step six, welding all welding seams of the convex surfaces of the unit plates to form a complete dome segmented wall plate, and welding radian-shaped longitudinal and transverse stiffening ribs on the convex surfaces of the dome wall plate. The arc shape of the stiffening rib is formed by cold bending and preliminary molding, and then the radian accuracy is adjusted by using a stiffening rib radian control device 5 (shown in figure 6) in cooperation with flame correction;

in the fourth step and the sixth step, the dome manufacturing quality is improved by adopting methods of rigid fixation, sectional desoldering and symmetrical welding.

And step seven, after the welding of the stiffening ribs is finished, the dome section plate is taken down from the forming die, and the dome section plate is turned over by 180 degrees to weld (concave surface) the inner side welding seam of the section plate. Welding and splicing welding seams are welded by adopting a seesaw type leveling device 8 (shown in a figure 10) to replace a forklift auxiliary submerged arc welding machine, so that the welding conditions can meet the requirements in the fifth step all the time;

and step eight, taking the longitudinal and transverse stiffening rib angle steel frame as a unit, and searching for the arrangement commonality of the anchoring nails in the unit to design a common template (Y2) (see figure 11). Positioning holes (Y22) with the diameter of 5mm are formed in the lofting positions of the anchoring nails on the template, and the template is adopted to position the anchoring nails. Welding by adopting a special stud welding machine after polishing;

after the block plate is prefabricated, carrying out anticorrosive coating on the block plate in a transportation sand blasting paint workshop;

step ten, after the block board paint is qualified, hoisting and transporting three layers and four layers of the dome to the existing general tire mold to splice two adjacent block boards again, wherein the field splicing amount of the three layers of the dome is reduced by half, and the fourth layer of the dome is spliced into a whole;

and sixthly, welding process sequence of the stiffening ribs: firstly welding staggered welding seams (9) between large stiffening ribs and unit plates, then welding seams between the remaining small stiffening ribs and the unit plates, and finally welding the welding seams between the stiffening ribs, wherein 4-6 welders perform sectional back welding on two sides of the stiffening ribs from the middle to two ends during welding. The same method is adopted for the small angle steel. The welding direction is from the middle to both ends. The fillet welds between the stiffeners and the segmented plates are staggered welds (see fig. 9). After the angle steel stiffening ribs are welded, the block plates can be taken down after forming on the forming die for at least 24 hours;

before step seven, additional stiffening ribs (61) are added to the part where the stiffening ribs of each block plate are sparse, particularly around the plate (see figure 8), so as to prevent welding deformation.

The embodiment is described by taking a Pakistan Kalazi K-2/K-3 nuclear power project nuclear island safety sense steel lining shell type semispherical dome as an example, the structure of the dome comprises 5 layers from bottom to top, wherein each layer of dome is composed of a plurality of split plates 1, as shown in figure 1, the split plates are formed by welding unit plates 11, the inner sides of the split plates are brushed with nuclear grade anticorrosive paint, and the outer sides of the split plates are welded with transverse and longitudinal stiffeners 12 and anchoring nails 13. After the prefabrication of the block plate workshop is completed, the block plate workshop is assembled into a whole on site, finally, large-scale hoisting equipment is adopted to integrally hoist and place, the lower opening of the first layer of the dome is connected with the upper opening of the steel lining cylinder body in a welding mode, and the dome and the steel lining cylinder body of the containment form a complete whole, so that the third leakage barrier function is achieved.

The invention solves the construction problems of excessive number of the block plates, high material loss rate, one-step molding of the block plates, submerged arc welding and splicing of the unit plates, large field splicing engineering quantity and the like. The invention optimizes the number of the block plates, deeply applies the submerged-arc welding unit plate assembly technology, and innovatively adopts the large-breadth block plate workshop assembly technology, thereby effectively improving the construction quality and the construction efficiency, reducing the field assembly engineering quantity, reducing the safety risk of high-altitude operation and shortening the field assembly period by more than 24 days.

The dome manufacturing process of the present invention is shown in fig. 2. The method comprises the following steps:

(1) Preparation for construction

(1) Plate optimization preparation

The design drawing is divided into five layers, the first-third layer of the block plates are optimized, and each layer of the first-third layers is divided into 48 block plates. And on the principle that the initial angle and the elevation are unchanged, after optimization, the first, second and third layers of dome plates are optimized into 24 blocks by 48 originally designed arc plates spliced on site. The number of the first-third layers of the dome field assembling plates is reduced by 72, and the field assembling workload is reduced by 40%.

(2) Cell plate expansion calculations

The dome steel lining is analyzed according to a polar cap warp mixed spherical expansion method and a TAKELA three-dimensional model, the expansion value is closer when the blocks are smaller, the block plates are refined and decomposed, and each block plate is divided into four unit plates to be subjected to curved surface splicing on the premise of meeting the technical standard and quality, so that the workshop seam is increased. And listing calculation formulas of all parameters according to an expansion method, then calculating specific numerical values of all parameters through excel software, and finally determining the size of each unit plate of the dome steel lining and the position of an angle steel positioning line through CAD lofting according to calculation results.

(3) Design of moulding bed

A section of sphere with evenly distributed wefts of R =23400mm is cut out to serve as a design prototype of the tire mold, and the positions where the wefts pass through become the upper opening radian and the placing angle of the inclined struts of the tire mold, as shown in figure 3. The base 22 section steel of the tire mould 2 is ordinary I-shaped steel with the type I25a, the inclined supports are made of arc steel plates with the thickness of 6mm and 12mm, the longitudinal arc angle steel 21 between the inclined supports is made of angle steel 80 multiplied by 10, and the materials are all carbon steel of Q235B. The dome tire mold which meets the construction requirement size is formed by designing a tire mold base, inclined supports with different radians and angles, longitudinal arc-shaped angle steel and connecting the components in a welding mode.

(4) Tyre mould improvement

According to the hemispherical characteristic, the moulding bed can be made into a universal moulding bed. The size of the general tire mold is manufactured according to the largest and widest size of the block plates, and arc-shaped angle steel is added in the radial direction according to the difference of the width size of each layer of block plates in local transformation. The structure of the dome fourth layer and fifth layer split plates is designed as follows: the fourth layer of layered board is the semicircle board of radius 3.8m, increases arc angle steel according to radius R =3800mm on the child mould, realizes that a membrane is multi-purpose. The fifth layer is 1 block plate with the diameter of 1m, and the fetal membrane does not need to be reconstructed.

(2) Lofting and blanking

The steel plate is blanked by adopting a flame cutting method, the used equipment is a numerical control cutting machine, and the CAD is converted into programming input numerical control for lofting and blanking before blanking. The marking device is an important functional component of the numerical control cutting machine. The principle of the marking device is that high-mesh zinc powder is melted by high-temperature flame and then sprayed on the surface of a steel plate to form uniform and clear zinc powder lines, and the lines have certain corrosion resistance and wear resistance. The function is utilized to loft the angle steel positioning line, and finally, the unit plate edge line cutting is carried out. And (3) carrying out blanking cutting on the angle steel stiffening rib according to the size after lofting, reserving 100mm of field installation allowance at the upper opening of each unit plate, and reserving 50mm of field assembling allowance at the side edge of 1 unit plate in each group of unit plates.

(3) Unit board splicing (convexity)

Each block plate in the first layer to the fourth layer consists of 4 unit plates, the block plate in the fifth layer consists of 2 unit plates, the unit plates are transported to a forming die to be sequentially arranged and spliced into the block plate, in order to ensure that the plates are attached to the forming die during the time combination, the U-shaped iron 32 which is processed in a standardized mode is used for crossing over the longitudinal arc-shaped angle steel of the forming die and is welded below the block plate in a spot mode, and the block plate is attached to the longitudinal arc-shaped angle steel 21 of the forming die (shown in figure 4) by hitting a wedge 31.

Before welding, the plate and the moulding bed are attached to the periphery of the steel plate by using U-shaped clamps and wedges, and the sequence of driving the wedges is performed by four persons at the same time from the middle to the two ends at intervals of 380 mm.

The welding is carried out by adopting the upper curved surface submerged arc welding 42 of the forming die. The general applicable position of submerged arc welding is flat welding and the seam can not be suspended. Longitudinal arc-shaped angle steel is additionally arranged on the forming die below the splicing seams to meet the requirements of welding positions of flat welding, and a forklift 41 is adopted to lift one section of the forming die (see figure 5), so that the welding positions of the splicing seams on the forming die are in an approximately horizontal state within a range of-15 degrees to +15 degrees with the horizontal plane. In order to prevent the tire mold from sliding on the steel platform in the lifting process, a steel plate backer is welded on the outer side of one section of the tire mold, which is in contact with the steel platform, before lifting (see figure 5).

Before welding, the welding track is subjected to flame baking for removing moisture, and the baking range is as follows: the two sides of the welding bead are respectively 40-60 mm, and the baking time is as follows: before the first welding seam is welded, the welding seam is kept synchronous with submerged-arc welding, and the welding seam is not baked at one time.

(4) Forming of angle steel stiffening rib

The angle steel stiffening rib is formed in advance by cold bending on a section steel stretch bender, the formed angle steel is checked piece by using a design arc sample plate, and if the arc of the stretch-bending formed angle steel is not consistent with the sample plate, the radian precision is adjusted by using a radian control device 5. The arc control device consists of a limit plate 52, a screw jack 51, L-shaped iron 53 and oblique iron 54, wherein the limit plate and the L-shaped iron are welded on a steel platform 55, as shown in figure 6.L type iron distributes along R =23406mm radian laying-out line, and it is fixed that the angle steel is carried out with the cooperation drift use to mainly used angle steel radian is spacing, and spacing backup pad is screw jack's quiet power strong point, through adjusting screw jack, adopts quiet power roof pressure with angle steel and radian line coincidence. And (5) matching flame correction until the radian reaches the design requirement. The surface was inspected with a 3m long arc inspection template (Y1) (see fig. 7) during the calibration process until the arc reached the design requirements.

(5) Blanking of angle steel stiffening rib

Blanking the angle steel stiffening ribs with qualified radian according to the positioning lofting size of the angle steel on the block plate, and marking part numbers

(6) Assembling and welding stiffening ribs

(1) Group to group

The radian molding of the dome is realized by adopting a moulding bed and a bent angle steel stiffening rib. And vertically placing the longitudinal and transverse angle steel stiffening ribs which are formed by bending on a steel plate according to the direction of a designed blueprint according to the numerical control lofting angle steel positioning line, and performing spot welding and fixing after adjusting the verticality of the angle steel to meet the requirement.

(2) Welding of

And adopting a rigid fixing method of additional angle steel. The welding of the angle steel stiffening rib and the block plate adopts gas shield welding, the welding mode is double-sided pattern welding, in order to prevent the block plate from contracting and arching upwards during welding, an I-shaped steel beam is required to be pressed on the angle steel stiffening rib before the welding of the angle steel stiffening rib, the deformation of the block plate is prevented during welding, and the I-shaped steel beam is fixed on the moulding bed.

Additional stiffening ribs (see figure 8) are additionally arranged at the sparse place of stiffening ribs of each block plate, particularly around the plate, so that welding deformation is prevented, the radian of the formed block plate is ensured, the specification of the additional stiffening ribs is L125 multiplied by 80 multiplied by 10, the opening surface of the angle steel faces inwards, long limbs of the angle steel and the block plate are welded together in a pattern mode, the distance is 400-500mm, and the length of a welding line is 30-50mm.

Sequence of welding processes

Firstly welding the welding seams of the large angle steel and the steel plate, then welding the welding seams of the rest small angle steel and the steel plate, and finally welding the welding seams between the angle steel, wherein 4-6 welders perform sectional back welding on two sides of the angle steel from the middle to two ends during welding. The same method is adopted for the small angle steel. The welding direction is from the middle to both ends. The fillet welds between the stiffeners and the segmented plates are staggered welds (see fig. 9). And (3) finishing welding the angle steel stiffening ribs, and taking off the block plates at least for 24 hours after the block plates are formed on the forming die in order to ensure that the radian of the block plates meets the requirement.

(7) Unit board splicing (concave)

And after the dome partition plate is taken off from the forming die, the dome partition plate is turned for 180 degrees to perform submerged arc automatic welding on the back surface of the shell, and a submerged arc seesaw type leveling device is designed and manufactured according to the leveling principle. The seesaw type leveling device 8 (shown in figure 10) is composed of a rotating shaft supporting frame 81 and a counterweight leveling device 82, the rotating shaft supporting frame in the figure is arranged in the middle of the dome plate, and a clamping groove is formed in the supporting frame, so that the dome plate and the supporting frame are fixed to form a seesaw; the end head is communicated with a balance weight leveling device, and the hand chain reversing lifting balance weight is pulled to achieve the leveling purpose. The seesaw type leveling device is manufactured to replace a forklift, the forklift is liberated, and the materials and semi-finished products are transported in time, so that the production is continuous, the working procedures are connected compactly, and the engineering progress is guaranteed; the liberation of fork truck, the reduction of equipment machine class has reduced the prefabrication cost to a certain extent. The requirements of submerged arc welding are the same as that of upper mould split welding (concave surface welding). After completion of the welding, the steel plate-joining weld was subjected to 100% VT, 100% LT, 100% PT, 2% RT, and the stiffening angle weld was subjected to 100% VT, 10% PT, and the next step was performed after passing.

(8) Assembling and welding of anchoring nails

(1) Group to group

In order to prevent the deformation of the dome block plate, the formed block plate cannot be reversely buckled on the ground at will to weld anchoring nails, and stud welding is carried out on a forming die or a special storage rack.

Before welding, a welding point of a welding nail is marked on the wall plate according to design requirements, and the marked part is polished by a polishing machine to expose the metal luster. The anchoring nails are positioned by using an anchoring nail lofting template, and the template is made of sheet iron (Y21), so that the anchoring nails are light in weight, good in toughness and capable of being repeatedly used. The templates are manufactured according to layers, the circular large angle steel is used as a boundary, and 3 templates, 4 blocks in the second layer, 4 blocks in the third layer and 1 block in the fourth layer need to be manufactured in the first layer. The longitudinal ring is taken as a unit towards the stiffening rib angle steel frame, the anchoring nails in the unit are searched for to arrange the commonality to design a common template (Y2), positioning holes (Y22) with the diameter of 5mm are formed in the lofting positions of the anchoring nails on the template (see figure 11), a large amount of lofting time is saved by adopting the template positioning anchoring nails, the repeated work is avoided, and the error occurrence rate is greatly reduced. After the template is lofted and positioned, the template is carefully checked and welded, so that the dislocation of the template is avoided.

(2) Welding of

The anchoring nails are phi 8 multiplied by 80 welding nails, the lofting template is adopted to determine the welding positions of the anchoring nails before welding, and a special stud welding machine is adopted to weld after polishing. The weld was completed by a 100% VT, 10% hammer test.

The anchoring nail lofting template is made of sheet iron and the like, and a plurality of holes are formed in the anchoring nail lofting template and used for positioning and lofting of the anchoring nails.

(9) Sand blasting paint

(1) Sand blasting

And rust, dust, moisture, oil stain and the like in a welding line area are removed by adopting a sand blasting derusting process, and the roughness reaches grade Sa3 in a design file.

(2) Coating of

The coating material system is PIC100I, and the coating thickness needs to meet the design requirement.

(10) Large-breadth block board assembly

After the prefabrication of the third layer and the fourth layer of the block plates of the dome is finished, the block plates are hoisted and transported to the existing general moulding bed for secondary splicing. And cutting off the allowance of the spliced part before assembly, splicing two adjacent dome third layers into 12 whole bodies, and hoisting the whole bodies to a scaffold platform to assemble and weld the remaining 12 welding seams. The dome fourth layer is spliced into a whole, and the whole is hoisted in place and then spliced with the upper opening of the third layer.

(11) Numbering deposit

After the dome block plate is manufactured, component number identification is carried out according to a drawing, identification handwriting is clear, and the position is obvious. The partition plates are horizontally stored on a special bracket, and the number of each pile is not more than 5.

The invention is used for manufacturing the steel lining semispherical dome shell plate of the Pakistan Kalazi K-2/K-3 nuclear power project No. 3 unit, and achieves the following beneficial effects:

1) Construction period

The prefabrication period is shortened by 18 days, and the field assembly construction period is shortened by 24 days.

2) Quality of weld

And the ray detection (RT) of all butt weld joints is 274 in total, and the primary qualified rate of RT is 100%.

3) Mass of arc of shell

The radian error of the block plate manufactured by the traditional process is +/-10 mm/1m, and the manufacturing of the dome block plate by the method effectively controls the welding deformation, the radian error reaches +/-10 mm/3m, and the set technical requirements are met.

The radian is checked by using a template for checking the radian, and the template for checking the radian is used as a template for checking a theoretical radian system of a component and can be made of plywood or other materials.

4) Construction safety

The submerged automatic arc welding process is deeply used, so that the labor intensity is reduced, and the construction safety risk is reduced; by adopting the large-breadth block board workshop splicing technology, the field work load is reduced, the field splicing construction period is shortened, and the safety risk of field high-altitude splicing operation is reduced.

5) Economic efficiency

Prefabricating a workshop: shortening the prefabricating period by 18 days, saving 144 working days such as riveting workers, welding workers, labor workers and the like, and reducing 16 machine shifts of a 10t gantry crane and a plate bending machine.

Saving manual wages: 0.03 ten thousand yuan/workday × 144 workday =4.32 ten thousand yuan;

saving equipment platform shift fee: 0.0738 ten thousand yuan/shift × 16+0.1275 ten thousand yuan/shift × 16=3.22 ten thousand yuan;

assembling on site: the construction period is shortened by 24 days, the working days of welders, rivets and mechanics are reduced by 1056, and the number of square meters of a lap-joint and tear-joint welding operation platform is reduced by 110.25.

Saving manual wages: 0.03 ten thousand yuan/workday x 1056 workday =31.68 ten thousand yuan;

saving the cost for setting up a welding operation platform: 0.01161 ten thousand yuan/square meter × 110.25=1.28 ten thousand yuan;

the economic benefits sum up as follows: 4.32+3.22+31.68+1.28=40.50 ten thousand yuan.

In the embodiment, the third layer and the fourth layer of block plates adopt a large-breadth block plate assembly technology (if the first layer and the second layer cannot be assembled in a running way for the second time, the hoisting risk is overlarge in field assembly, the fifth layer is a block plate with the diameter of 1m, secondary assembly is not needed), the on-site welding seam assembly amount of the third layer and the fourth layer is reduced by 36.7%, the on-site assembly construction period is shortened by 24 days, the construction operation environment is improved, and the construction safety risk is reduced.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention in any way, and any person skilled in the art can make any simple modification, equivalent replacement, and improvement on the above embodiment without departing from the technical spirit of the present invention, and still fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. A manufacturing method of a lamella type semispherical dome structure of a containment vessel steel lining of a nuclear power station comprises the following steps:

step one, analyzing whether each layer of a dome steel lining needs to be re-partitioned, dividing the design of the dome layer needing to be re-partitioned into partitioned plates, and dividing the design of the partitioned plates into unit plates;

step two, manufacturing a forming die matched with the dome wall plate according to the size and drawing requirements of the dome layer needing to be re-partitioned according to analysis design;

thirdly, blanking a unit plate meeting the size precision through a numerical control cutting machine, and automatically lofting longitudinal and transverse angle steel positioning lines on the unit plate by using a marking device of the numerical control cutting machine;

transporting the unit plates onto a forming die, sequentially placing and splicing the unit plates into the forming die, and attaching the wall plates of the unit plates to the forming die by adopting a fixed tool;

step five, welding the unit plates on the forming die to form a block plate;

welding radian-molded longitudinal and transverse stiffening rib angle steel on the convex surface of the block plate to manufacture a dome block wall plate;

step seven, after the dome block wall plate is taken down from the moulding bed, turning over the dome block wall plate to weld the inner side weld joint;

step eight, mounting anchoring nails on the dome block wall plate;

step nine, performing anticorrosive coating on the dome block wall plate;

step ten, assembling all dome layers into a whole on site.

2. The manufacturing method of the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: in the first step, the dome steel lining is analyzed by adopting a polar cap meridian mixed spherical surface expansion method and a TAKELA three-dimensional model.

3. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and in the second step, arc-shaped angle steel is added in the radial direction according to the difference of the width size of each dome layer layered plate.

4. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and in the fourth step, a limiting device is arranged on the outer side of the contact position of the platform for placing the moulding bed and one end of the moulding bed.

5. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and fifthly, welding the unit plates on the forming die by adopting union welding and adopting union melt welding, adjusting the welding of the convex surface at the outer side by adopting a forklift, and using a seesaw type leveling device when welding the concave surface at the inner side to ensure that the welding positions of the unit plate splicing welding seams on the forming die are always in the range of-15 degrees to +15 degrees from the horizontal plane.

6. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and in the sixth step, after the radian-formed longitudinal and transverse stiffening rib angle steel is subjected to cold bending primary forming, the radian precision is adjusted by matching the radian control device with flame correction.

7. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and seventhly, adopting a seesaw type leveling device to assist submerged arc automatic welding, so that the welding position of the welding seam is always in the range of-15 degrees to +15 degrees from the horizontal plane.

8. The manufacturing method of the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 5 or 7, is characterized in that: the seesaw type leveling device comprises a rotating shaft supporting frame and a balance weight leveling device, wherein a unit plate is placed on the rotating shaft supporting frame, the rotating shaft supporting frame is positioned in the center of the bottom of the unit plate, a clamping groove is formed in the rotating shaft supporting frame, the unit plate is fixed with the supporting frame, the balance weight leveling device is positioned on the unit plate on one side of the rotating shaft supporting frame, and a submerged arc welding machine is arranged on the unit plate on the other side of the rotating shaft supporting frame.

9. The manufacturing method of the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: and step eight, taking the longitudinal and transverse stiffening rib angle steel frame on the dome block wall plate as a unit, searching for the arrangement commonality of the anchoring nails in the unit to design a common template for installing the anchoring nails, forming positioning small holes with the diameter of 5mm at the lofting positions of the anchoring nails on the template, and positioning the anchoring nails by adopting the template.

10. The method for manufacturing the lamella type semispherical dome structure of the steel lining of the nuclear power station containment vessel according to claim 1, is characterized in that: in the sixth step, the welding process sequence of the stiffening rib angle steel is as follows: firstly welding a welding seam of a larger angle steel and a steel plate, then welding a welding seam of the rest smaller angle steel and the steel plate, and finally welding the welding seam between the angle steel, wherein the welding seam is removed from the middle to two ends of the angle steel in sections when welding is carried out; the welding direction is from the middle to the two ends; fillet welds between the stiffening ribs and the block plates are staggered welds; after the angle steel of the stiffening rib is welded, the block plate can be taken down when the forming of the block plate on the moulding bed is at least 24 hours.

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