Storage device for heavy water reactor spent fuel and installation method thereof

Abstract

The invention belongs to the technical field of nuclear power, and particularly relates to a storage device for heavy water reactor spent fuel and an installation method of the storage device. The whole storage barrel is divided into the manufacturing process of multiple sections such as the upper structure, the multiple sections of barrel bodies and the lower structure, machining treatment is carried out with the annular plate at the bottom of the support as the datum plane, the manufacturing difficulty of all the sections is reduced, the machining precision of all the sections can be improved, and the machining efficiency is improved. The machining precision of each section is further controlled to be higher than the overall machining precision requirement of the storage barrel, allowance is reserved for micro deformation generated after each section is welded, and the overall machining precision of the storage barrel is effectively guaranteed; in the assembling process, the upper plate serves as a datum plane, so that the levelness of the surface of the bottom plate and the concrete pouring technology do not affect leveling of the storage cylinder any more, and errors gradually accumulated from bottom to top are effectively overcome. The overall installation precision of the storage cylinder is ensured, and spent fuel loading requirements are met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear power, and particularly relates to a storage device for spent fuel of a heavy water reactor and a mounting method thereof. BACKGROUND

[0002] The dry storage module for spent fuel of the heavy water reactor is internally embedded with multiple vertical storage cylinders, and the storage cylinder is a core device of the dry storage module for spent fuel. The leveling process during the installation of the storage cylinder is very important. If there is a flaw in the leveling of the storage cylinder, it will seriously affect the safety of the remote mechanical loading. For example, the spent fuel basket deviates from the axis, repeatedly collides with the cylinder wall during the falling process, and causes serious deformation, resulting in difficulty in retrieving the spent fuel basket. For another example, the spent fuel basket collides with the cylinder wall or even overturns and falls, resulting in damage and waste of the storage cylinder and the spent fuel basket.

[0003] The MACSTOR type storage module commonly used in the industry adopts the form of fixing the storage cylinder by the top plate. The leveling process for installing the storage cylinder only needs to level the plane of the upper surface of the top plate and the upper end of the storage cylinder. The bottom of the storage cylinder is a free end and can be heated and stretched up and down.

[0004] If the storage cylinder is fixed by the bottom plate instead of the top plate, the sequence of installing the storage cylinder will be changed to from bottom to top. The error of each step during the installation process will be gradually accumulated from bottom to top. The control link is complex. In addition, in engineering practice, the flaws in the installation process of the storage cylinder will only appear in the last few links, which will lead to overall rework and waste of huge manpower and resources. As can be seen, the installation difficulty brought by changing the storage cylinder to be fixed by the bottom is significantly improved. It is urgent to overcome many technical problems such as installation accuracy and installation efficiency of the storage cylinder. SUMMARY

[0005] In order to overcome the problems in the related art, a storage device for spent fuel of a heavy water reactor and a mounting method thereof are provided.

[0006] According to an aspect of an embodiment of the present disclosure, a storage device for spent fuel of a heavy water reactor is provided, which comprises a storage cylinder, a support and a pre-buried assembly. The storage device is fixedly installed on a bottom plate in a storage module, and a top plate of the storage module does not support the storage device. The storage cylinder is assembled in the order of an upper structure, a multi-section cylinder body and a lower structure. The pre-buried assembly comprises an upper plate, a lower plate and a plurality of anchor bolts. The lower plate is embedded in the bottom plate of the storage module, the upper plate is embedded and fixed on the surface layer of the bottom plate, and the upper surface of the upper plate is exposed to the bottom plate. The flatness of the upper surface of the upper plate is not more than 5 mm. The support is a tubular structure, which is sleeved and fixed on the outer wall of the storage cylinder; a ring plate is arranged on the bottom end of the support in a circumferential direction, the outer edge of the ring plate extends radially outward, and the inner edge of the ring plate extends radially inward; the flatness of the lower surface of the ring plate is not more than 3 mm; The flatness of the lower surface of the lower structure is not more than 3 mm compared with the lower surface of the ring plate; the perpendicularity of each cylinder compared with the lower surface of the ring plate is not more than 7 mm; the straightness of the whole multi-section cylinder after assembly is not more than 6 mm, and the straightness of the cylinder in each 3-meter range after assembly is not more than 3 mm; the perpendicularity of the upper structure compared with the lower surface of the ring plate is not more than 10 mm; The bottom end of the storage cylinder is suspended on the upper surface of the upper plate, the ring plate is mounted on the upper surface of the upper plate, and the outer wall of the support has a plurality of lugs extending radially outward; each anchor bolt is fixedly connected with the lower plate, the upper plate, the ring plate and one lug, respectively; taking the upper surface of the upper plate as a reference surface, the installation levelness of the lower surface of the ring plate is not more than 2 mm, and the perpendicularity of the center line of the storage cylinder in the full-length range is not more than 8 mm.

[0007] In a possible implementation, the storage device further comprises a plurality of positioning pin embedded parts and positioning pins, the plurality of positioning pin embedded parts and the positioning pins are arranged on the upper surface of the storage module top plate, the plurality of positioning pin embedded parts are uniformly distributed around the center of the storage cylinder, the positioning pins are arranged close to the storage cylinder and the positioning pin embedded parts, the upper surface flatness allows a deviation of ±1 mm, the levelness tolerance of each positioning pin embedded part is not more than 3 mm, the upper surface of each positioning pin embedded part is the highest point of the module top, and the positioning pins are used for centering and positioning of the adapter device and the storage cylinder.

[0008] According to another aspect of the embodiments of the present disclosure, a mounting method for a heavy water reactor spent fuel storage device is provided, the method is implemented based on the above-mentioned heavy water reactor spent fuel storage device, and the method comprises the following steps: Step one, the lower plate is positioned and mounted on the cushion layer of the storage module through expansion bolts, and the levelness of the lower plate is adjusted so that the levelness of the lower plate meets the preset requirements; Step two, a plurality of first nuts are welded on the preset positions on the upper surface of the lower plate, so that the horizontal deviation distance of each first nut from the center of the lower plate is not more than 1 mm, then the lower end of each anchor bolt is connected with one first nut to form a pre-fixed bolt group, so that the horizontal deviation distance of the top of each anchor bolt after installation from the center of the lower plate is not more than 2 mm; Step three, after installing a second nut on the upper part of each bolt, the upper plate with array bolt holes is axially sleeved into the pre-fixed bolt group, each anchor bolt is matched with a bolt hole, so that the upper plate is erected on each second nut, and the levelness of the upper plate can be adjusted by rotating any one or more second nuts. When the levelness of the upper plate meets the preset requirement, each second nut is fixed by spot welding with the lower surface of the upper plate; Step four, after the pre-embedded component is installed, the bottom plate concrete is poured, the flatness of the upper plate is less than 5mm after the bottom plate concrete is poured, and the installation tolerance of the exposed length of the anchor bolt is 0-1mm.

[0009] In a possible implementation, in step one, the levelness of the lower plate is adjusted by adjusting the number of stainless steel shims between the lower plate and the cushion layer.

[0010] In a possible implementation, in step two, the upper surface of the lower plate is provided with a plurality of positioning areas, the marking size of each positioning area is consistent with the outer diameter of the first nut, and each first nut is welded and fixed in a positioning area.

[0011] In a possible implementation, in step three, during the installation of the anchor bolt on the upper surface of the lower plate, the position of each anchor bolt is adjusted by using a simulation piece, then the upper plate is installed, and the simulation piece is removed after the installation of the upper plate. The simulation piece is consistent with the size and bolt hole layout of the upper plate, and a light material is used.

[0012] In a possible implementation, the lower layer of the bottom plate is bound before the installation of the anchor bolt, and the upper layer of the bottom plate is bound after the installation of the anchor bolt.

[0013] In a possible implementation, the upper surface of the upper plate and the lower surface of the lower plate are subjected to thermal spraying zinc anticorrosion, and the coating thickness is at least 350um.

[0014] In a possible implementation, after the storage cylinder is installed in place and fixed, the outside of the support is subjected to zinc spraying treatment, and the first cavity formed between the bottom end of the storage cylinder, the inner wall of the support and the upper plate is filled with grout until 10cm from the bottom of the storage cylinder; The position of each lug on both sides of the support is provided with a stiffener plate connected with the lug and the ring plate, the stiffener plate and the folded plate cooperate to form a second cavity, and the second cavity is filled with grout through the through hole reserved by the folded plate, so as to fill the second cavity; The position of each anchor bolt passing out of the lug is fixed by a nut and a cap, and is welded, a sleeve is arranged around the outside of the cap and the nut on the upper surface of the lug, and the cap and the nut inside the sleeve are filled with grout to wrap the cap and the nut inside the sleeve.

[0015] In a possible implementation, a plurality of discharge openings are formed in the top plate of the storage module, each of the discharge openings is opposite to one storage cylinder, and the storage device further comprises a support cylinder and a water retaining cylinder, wherein the support cylinder is arranged around the inner wall of the corresponding discharge opening and is used to support the discharge opening; the water retaining cylinder is arranged around the upper opening of the discharge opening, the water retaining cylinder is welded with the support cylinder below, and the upper edge of the water retaining cylinder is higher than the upper edge of the discharge opening and is used to prevent water on the outer surface of the top plate from flowing into the discharge opening; the support cylinder and the water retaining cylinder are installed by the following steps: Step five, after the top plate support scaffold and the bottom die are installed, the preset gap between the storage cylinder and the support cylinder is measured, steel nails with the same length as the preset gap are symmetrically nailed on the bottom die along the outer wall of the storage cylinder to position the inner diameter of the support cylinder, polystyrene extruded plates with the same thickness as the preset gap are inserted along the outer wall of the storage cylinder for reinforcement, the first half and the second half of the support cylinder are hoisted to the top of the storage cylinder, and the first half and the second half are assembled and fastened into a whole support cylinder, and the bolts between the first half and the second half are tightened; Step six, the gap error between the support cylinder and the storage cylinder is not more than 0.5 mm, the installation height of the support cylinder is adjusted based on the horizontal plane of the ring plate of the water retaining cylinder, after the support cylinder is positioned, the gaskets are uniformly inserted between the water retaining cylinder and the storage cylinder, after the water retaining cylinder and the support cylinder are ring-welded, the elevation of the ring plate of the water retaining cylinder is checked and adjusted again to the design value, and then the gaskets are removed.

[0016] The present disclosure has the beneficial effects that the overall processing of the storage cylinder is divided into an upper structure, a multi-section cylinder body and a lower structure and other segmented manufacturing processes, the base bottom ring plate is used as a reference surface for processing, the manufacturing difficulty of each segment is reduced, the processing precision of each segment is improved, the processing precision of each segment is further controlled to be higher than the overall processing precision requirement of the storage cylinder, a small amount of deformation generated after welding of each segment is left with a margin, the overall processing precision of the storage cylinder is effectively ensured, in the assembly process, the upper plate is used as a reference surface, so that the levelness of the bottom plate surface and the concrete pouring process no longer affect the leveling of the storage cylinder, and the gradually accumulated error from bottom to top is effectively overcome. The overall installation precision of the storage cylinder is ensured, and the need for spent fuel loading is met. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of a storage device for spent fuel of a heavy water reactor according to an embodiment of the present disclosure.

[0018] Figure 2 is a schematic diagram of a pre-embedded assembly according to an embodiment of the present disclosure.

[0019] Figure 3 is a schematic diagram of a support according to an embodiment of the present disclosure.

[0020] In the drawings: 1, storage cylinder; 2, support; 3, embedded component; 4, support cylinder; 5, water retaining cylinder; 6, shielding plug; 7, rain cover; 11, upper structure; 12, cylinder body; 13, lower structure; 21, lug; 22, ring plate; 31, upper plate; 32, lower plate; 33, anchor bolt; 211, stiffener; 212, folded plate; 213, sleeve. DETAILED DESCRIPTION

[0021] The present disclosure will be further described in conjunction with the drawings and specific embodiments.

[0022] Unless otherwise defined, technical and scientific terms used in the present disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure; the term "comprising" and any variation thereof in the present disclosure is intended to cover a non-exclusive inclusion; it is apparent that the embodiments described in the present disclosure are only a part of the embodiments of the present disclosure, and not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0023] In the present disclosure, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present disclosure. The phrase appears at various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] The storage device is fixedly installed inside a spent fuel storage module of a concrete structure, Figure 1 is a schematic diagram of a storage device for spent fuel of a heavy water reactor according to an embodiment of the present disclosure, as Figure 1 As shown, the storage device includes a storage cylinder 1, a support 2 and an embedded component 3; the storage device is fixedly installed on a bottom plate inside the storage module, and the top plate of the storage module no longer supports the storage device. The storage cylinder 1 is assembled in the order of an upper structure 11, a multi-section cylinder body 12 (for example, 3-section cylinder body) and a lower structure 13; Figure 2 is a schematic diagram of an embedded component according to an embodiment of the present disclosure, as Figure 2As shown, the pre-embedded component 3 comprises an upper plate 31, a lower plate 32 and a plurality of anchor bolts 33; the lower plate 32 is embedded in the bottom plate of the storage module, the upper plate 31 is embedded and fixed on the surface layer of the bottom plate, and the upper surface of the upper plate 31 is exposed to the bottom plate, and the flatness of the upper surface of the upper plate 31 is not more than 5mm.

[0025] Figure 3 is a schematic view of a support shown by an embodiment of the present disclosure, as Figure 3 As shown, the support 2 is a tubular structure, the support 2 is sleeved and fixed on the outer wall of the storage cylinder 1; the bottom end of the support 2 is circumferentially provided with a ring plate 22, the outer edge of the ring plate 22 extends radially outward, and the inner edge of the ring plate 22 extends radially inward; the flatness of the lower surface of the ring plate 22 is not more than 3mm; during the processing and manufacturing of the storage cylinder 1, the lower surface of the ring plate 22 is used as a reference surface, and the flatness of the lower surface of the lower structure 13 is not more than 3mm compared with the lower surface of the ring plate 22; each section of the cylinder body 12 is used to control the perpendicularity and straightness of the whole storage cylinder 1, and the perpendicularity of each section of the cylinder body 12 is not more than 7mm compared with the lower surface of the ring plate 22; the straightness of the whole multi-section cylinder body 12 after assembly is not more than 6mm, and the straightness of the cylinder body 12 within every 3m range of the multi-section cylinder body 12 after assembly is not more than 3mm; the perpendicularity of the upper structure 11 compared with the lower surface of the ring plate 22 is not more than 10mm.

[0026] The bottom end of the storage cylinder 1 is suspended on the upper surface of the upper plate 31, the ring plate 22 is installed on the upper surface of the upper plate 31, and the outer wall of the support 2 has a plurality of lugs 21 extending radially outward; each anchor bolt 33 is fixedly connected with the lower plate 32, the upper plate 31, the ring plate 22 and one lug 21 respectively; taking the upper surface of the upper plate 31 as a reference surface, the installation levelness of the lower surface of the ring plate 22 is not more than 2mm, and the perpendicularity of the center line of the storage cylinder 1 within the whole length range is not more than 8mm.

[0027] The present disclosure divides the whole processing of the storage cylinder into a plurality of segmented manufacturing processes such as the upper structure, the multi-section cylinder body and the lower structure, processes the ring plate at the bottom of the support as a reference surface, reduces the manufacturing difficulty of each segment, is conducive to improving the processing precision of each segment, and further controls the processing precision of each segment to be higher than the overall processing precision requirement of the storage cylinder, leaves a margin for the slight deformation generated after welding of each segment, effectively ensures the overall processing precision of the storage cylinder; during the assembly process, the present disclosure takes the upper plate as a reference surface, so that the levelness of the bottom plate surface and the concrete pouring process no longer affect the leveling of the storage cylinder, effectively overcoming the cumulative error from bottom to top. Ensure the overall installation precision of the storage cylinder to meet the needs of spent fuel loading.

[0028] In a possible implementation, the following steps are adopted to install the pre-embedded assembly: Step one, the lower plate is positioned and installed on the cushion layer of the storage module by expansion bolts, and the levelness of the lower plate is adjusted by adjusting the stainless steel gasket between the lower plate and the cushion layer.

[0029] Step two, the lower plate is provided with a plurality of positioning areas, and the marking size of each positioning area can be consistent with the outer diameter of the first nut, so as to facilitate positioning of each first nut during welding, and each first nut is welded and fixed in a positioning area, and the horizontal deviation distance of each first nut from the center of the lower plate is not more than 1mm, and then the lower end of each anchor bolt is connected with a first nut to form a pre-fixed bolt group, so that the horizontal deviation distance of the top of each anchor bolt from the center of the lower plate after installation is not more than 2mm.

[0030] Step three, after a second nut is installed on the upper part of each bolt, the upper plate with array bolt holes is axially sleeved into the pre-fixed bolt group, each anchor bolt is inserted into a bolt hole to cooperate, so that the upper plate is erected on each second nut, and rotating any one or more second nuts can adjust the levelness of the upper plate, and in the case that the levelness of the upper plate after leveling meets the preset requirements, each second nut is spot-welded and fixed to the lower surface of the upper plate.

[0031] Step four, after the pre-embedded assembly is installed, the bottom plate concrete is poured, and the flatness of the upper plate after pouring of the bottom plate concrete is less than 5mm, and the installation tolerance of the exposed length of the anchor bolt is 0-1mm.

[0032] The pre-embedded assembly of the present disclosure adopts a split adjustable structure of the upper plate, the lower plate and the anchor bolt, which facilitates the construction personnel to adjust the leveling from bottom to top according to the actual working conditions of the actual bottom plate level, thereby flexibly adapting to different construction scenes and improving the accuracy and efficiency of leveling. In addition, the leveling of the pre-embedded assembly is prior to the pouring of the bottom plate, so that the levelness of the bottom plate surface and the concrete pouring process have little influence on the leveling of the storage cylinder, which can realize the layer-by-layer adjustment of the levelness of the storage cylinder base, effectively fix the storage cylinder after pouring of the bottom plate, and at the same time guarantee the leveling accuracy and installation firmness of the storage cylinder.

[0033] In a possible implementation, in step three, during the process of installing the anchor bolt on the upper surface of the lower plate, a simulation piece is used to constrain and adjust the position of each anchor bolt, and then the upper plate is installed, and after the upper plate is installed, the simulation piece is removed, so that after the simulation piece is removed, each bolt can be smoothly inserted into the corresponding bolt hole of the upper plate, and the horizontal deviation distance of the top of each bolt from the center of the lower plate is less than or equal to 2mm. The simulation piece is consistent in size and bolt hole layout with the upper plate, and is made of light material (such as aluminum or resin material).

[0034] In a possible implementation, the lower layer of steel bars of the bottom plate is tied before the anchor bolt installation, and the upper layer of steel bars of the bottom plate is tied after the anchor bolt installation.

[0035] In a possible implementation, the upper surface of the upper plate and the lower surface of the lower plate are subjected to thermal spraying of zinc for corrosion prevention, and the coating thickness is at least 350 um. After the storage cylinder is installed and fixed in place, the outside of the support is subjected to zinc spraying treatment, and the first cavity formed between the bottom end of the storage cylinder, the inner wall of the support, and the upper plate is filled with grout until 10 cm from the bottom of the storage cylinder.

[0036] As shown in Figure 3 , the stiffener plate 211 connecting the lug 21 and the ring plate 22 is arranged on both sides of each lug 21 of the support 2, the folded plate 212 is arranged on the side opening of the stiffener plate 211, the stiffener plate 211, the folded plate 212, the lug 21, and the ring plate 22 form a second cavity, and the through hole reserved by the folded plate 212 is used to fill the second cavity with grout. Each anchor bolt 33 passes through the position of the lug 21 and is fixed by a nut and a nut cap, and can be welded by a 2mm fillet weld to prevent loosening. The lug 21 is provided with a sleeve 213 around the outside of the nut cap and the nut, and the sleeve is filled with grout to wrap the nut cap and the nut inside the sleeve. In the above manner, the lug, the anchor bolt, the ring plate, and the fixed connection position therebetween are effectively wrapped, prevented from corrosion, and supported.

[0037] In a possible implementation, referring to Figure 1 , a plurality of discharge ports are arranged on the top plate of the storage module, each discharge port is opposite to one storage cylinder 1, the storage device further includes a support cylinder 4 and a water blocking cylinder 5, the support cylinder 4 is arranged around the inner wall of the corresponding discharge port and is used to support and fix the discharge port, and the water blocking cylinder 5 is arranged around the upper opening of the discharge port, the water blocking cylinder 5 is welded with the support cylinder 4 below, the upper edge of the water blocking cylinder 5 is higher than the upper edge of the discharge port and is used to block the water flow from the outer surface of the top plate into the discharge port, and a rain cover 7 is arranged on the upper end of the water blocking cylinder 5. The support cylinder 4 and the water blocking cylinder 5 are installed by the following steps.

[0038] Step five, after the top plate support scaffold and the bottom mold are installed, the preset gap (for example, 20 mm) between the storage cylinder and the support cylinder is measured, steel nails with a length equal to the preset gap are symmetrically nailed on the bottom mold along the outer wall of the storage cylinder to position the inner diameter of the support cylinder, 20mm-thick polystyrene extruded plates are added to the outer wall of the storage cylinder for reinforcement, the first half and the second half of the support cylinder are hoisted to the top of the storage cylinder, the first half and the second half are assembled and fastened to form a whole support cylinder, and the bolts between the first half and the second half are tightened to ensure that the joint is tight.

[0039] Step six, the gap error between the support cylinder and the storage cylinder is not more than 0.5mm, and the installation height of the support cylinder is adjusted appropriately based on the horizontal plane of the ring plate of the water retaining cylinder. After the positioning and fine adjustment of the support cylinder, the gaskets are uniformly inserted between the water retaining cylinder and the storage cylinder to prevent welding deformation, which reduces the distance between the water retaining cylinder and the storage cylinder, and can ensure that the subsequent loading and unloading ring can be smoothly put in. After the ring welding connection of the water retaining cylinder and the support cylinder, the elevation of the ring plate of the water retaining cylinder is adjusted to the design value again, and then the gaskets are taken out.

[0040] In the present disclosure, if the water retaining cylinder and the support cylinder are welded and fixed at the factory, it is beneficial to control the welding thermal deformation, but after intensive storage, the distance between the two storage cylinders is significantly reduced, the steel bars of the module top plate are densely arranged, and the installation of the steel bars will further reduce the operation space if the water retaining cylinder is installed first. It is not convenient to bind the steel bars of the top plate, and it is not convenient to transport the water retaining cylinder and the support cylinder, so it is necessary to separate the two components and install them on site.

[0041] In one possible implementation, the storage device further comprises a plurality of positioning pin embedded parts and positioning pins, the plurality of positioning pin embedded parts and the positioning pins are arranged on the upper surface of the storage module top plate, the plurality of positioning pin embedded parts are evenly distributed around the center of the storage cylinder, and the positioning pins are arranged near the storage cylinder and the positioning pin embedded parts. The positioning pin embedded part serves as a reference plane for positioning the upper part of the shielding transport container on the storage cylinder, the flatness of the upper surface of the positioning pin embedded part allows a deviation of ±1mm, and the horizontal tolerance of each positioning pin embedded part is not more than 3mm. The upper surface of the storage module top plate is fixedly embedded with a plurality of positioning pin embedded parts around each storage cylinder, and the upper surface of the module top plate concrete and the water retaining cylinder ring plate cannot be higher than the upper surface of the positioning pin embedded part, so that the upper surface of the positioning pin embedded part is the highest point of the module top, to ensure that the shielding transport container is located on the plurality of positioning pin embedded parts and is on the same horizontal plane.

[0042] The positioning pin is a positioning device of the adapter device and the storage cylinder pair, and also determines whether the shielding transport container can be finally centered with the storage cylinder pair to prevent the fuel from colliding with the cylinder wall when being lowered into the storage cylinder. In order to ensure the positioning of the positioning pin, a special tool for installing the positioning pin is made on site to facilitate the determination of the position of the positioning pin and ensure the centering with the storage cylinder.

[0043] The above has described various embodiments of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A storage device for heavy water reactor spent fuel, characterized in that: The storage device comprises: a storage cylinder, a support, and a pre-embedded component; the storage device is fixedly mounted on the bottom plate of the storage module, and the top plate of the storage module does not support the storage device; the storage cylinder is assembled in the order of an upper structure, a multi-section cylinder, and a lower structure; The embedded assembly includes: an upper plate, a lower plate and a plurality of anchor bolts; the lower plate is embedded in the bottom plate of the storage module, the upper plate is embedded and fixed to the surface of the bottom plate, and the upper surface of the upper plate is exposed from the bottom plate, and the flatness of the upper surface of the upper plate does not exceed 5mm; The support is a tubular structure, which is sleeved and fixed to the outer wall of the storage cylinder; a ring plate is provided around the bottom end of the support, the outer edge of the ring plate extends radially outward, and the inner edge of the ring plate extends radially inward; the flatness of the lower surface of the ring plate does not exceed 3mm; The flatness of the lower surface of the lower structure is no more than 3mm compared to the lower surface of the ring plate; the verticality of each cylinder section is no more than 7mm compared to the lower surface of the ring plate; the overall straightness of the assembled multiple cylinder sections is no more than 6mm, and the straightness of the cylinder sections within every 3 meters of the assembled multiple cylinder sections is no more than 3mm; the verticality of the upper structure is no more than 10mm compared to the lower surface of the ring plate; The bottom end of the storage cylinder is suspended above the upper surface of the upper plate, the ring plate is mounted on the upper surface of the upper plate, and the outer wall of the support has a plurality of lugs extending radially outward; each anchor bolt is fixedly connected to the lower plate, the upper plate, the ring plate, and one lug respectively; with the upper surface of the upper plate as the reference plane, the installation horizontality of the lower surface of the ring plate does not exceed 2 mm, and the verticality of the centerline of the storage cylinder does not exceed 8 mm over the entire length.

2. The storage device for heavy water reactor spent fuel according to claim 1, characterized in that: The storage device also includes a plurality of positioning pin embedded parts and positioning pins, and the plurality of positioning pin embedded parts and positioning pins are arranged on the upper surface of the top plate of the storage module. The plurality of positioning pin embedded parts are evenly distributed around the center of the storage cylinder. The positioning pins are arranged at a position close to the storage cylinder and the positioning pin embedded parts. The flatness of the upper surface is allowed to deviate by ±1mm. The horizontality tolerance of each positioning pin embedded part does not exceed 3mm. The upper surface of each positioning pin embedded part is the highest point of the module top. The positioning pins are used to align and position the adapter device with the storage cylinder.

3. A method for installing a heavy water reactor spent fuel storage device, characterized in that: The method is implemented based on the storage device for heavy water reactor spent fuel according to claim 1 or 2, and the method comprises: Step 1: The lower plate is positioned and installed on the cushion layer of the storage module using expansion bolts, and the levelness of the lower plate is adjusted so that the levelness of the lower plate meets the preset requirements; Step 2: Weld multiple first nuts at preset positions on the upper surface of the lower plate, so that the horizontal deviation between each first nut and the center of the lower plate does not exceed 1 mm. Then, install and connect the lower end of each anchor bolt with a first nut to form a pre-fixed bolt group, so that the horizontal deviation between the top of each anchor bolt and the center of the lower plate after installation does not exceed 2 mm. Step 3: After installing a second nut on the upper part of each bolt, the upper plate with the array bolt holes is axially inserted into the pre-fixed bolt group, and each anchor bolt is inserted into a bolt hole to fit, so that the upper plate is mounted on each second nut. By rotating any one or more second nuts, the levelness of the upper plate can be adjusted. When the levelness of the upper plate meets the preset requirements, each second nut is spot welded to the lower surface of the upper plate; Step 4: After the embedded components are installed, pour the base plate concrete. After the base plate concrete is poured, the flatness of the upper plate is less than 5mm, and the installation tolerance of the exposed length of the anchor bolts is 0~1mm.

4. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: In step one, the levelness of the lower plate is adjusted by adjusting the number of stainless steel spacers between the lower plate and the cushion layer.

5. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: In step 2, a plurality of positioning areas are provided on the upper surface of the lower plate, the marking size of each positioning area is consistent with the outer diameter of the first nut, and each first nut is welded and fixed in a positioning area.

6. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: In step three, during the installation of anchor bolts on the upper surface of the lower plate, the positions of the anchor bolts are adjusted using simulation parts, and then the upper plate is installed. After the upper plate is installed, the simulation parts are removed. The simulation parts are consistent with the size and bolt hole layout of the upper plate and are made of lightweight materials.

7. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: The lower layer of steel bars of the base plate are tied before the anchor bolts are installed, and the upper layer of steel bars of the base plate are tied after the anchor bolts are installed.

8. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: Thermal spraying zinc is used on the upper surface of the upper plate and the lower surface of the lower plate for corrosion protection, with a coating thickness of at least 350um.

9. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: After the storage tube is installed and fixed in place, the outside of the support is zinc-sprayed, and the first cavity formed between the bottom of the storage tube, the inner wall of the support and the upper plate is poured with slurry until it is 10 cm away from the bottom of the storage tube; Stiffening plates connecting the lugs and the ring plate are respectively provided on both sides of each lug of the support. The stiffening plates cooperate with the folding plates to form a second cavity. Slurry is poured into the second cavity through the through holes reserved in the folding plates to fill the second cavity. The position where each anchor bolt passes through the lug is fixed by a nut and a cap and welded. A sleeve is set on the upper surface of the lug around the cap and the outside of the nut, and grout is poured into the sleeve to wrap the cap and nut inside the sleeve.

10. The installation method for a heavy water reactor spent fuel storage device according to claim 3, characterized in that: A plurality of discharge ports are provided on the top plate of the storage module, each of which faces a storage cylinder. The storage device further comprises a support cylinder and a water retaining cylinder, wherein the support cylinder is arranged around the inner wall of the corresponding discharge port for supporting the discharge port; the water retaining cylinder is arranged around the inner wall of the upper opening of the discharge port, the water retaining cylinder is welded to the support cylinder below, and the upper edge of the water retaining cylinder is higher than the upper edge of the discharge port for preventing water on the surface of the top plate from flowing into the discharge port; the support cylinder and the water retaining cylinder are installed by the following steps: Step 5: After the top plate support scaffolding and bottom formwork are installed, the preset gap between the storage tube and the support tube is measured. Steel nails of the same length as the preset gap are symmetrically nailed on the bottom formwork along the outer wall of the storage tube to locate the inner diameter of the support tube. Polystyrene extruded board of the same thickness as the preset gap is inserted along the outer wall of the storage tube for reinforcement. The first half and the second half of the support tube are hoisted to the top of the storage tube, the first half and the second half are assembled and fastened to form a whole support tube, and the bolts between the first half and the second half are tightened. Step six: the gap error between the support tube and the storage tube shall not exceed 0.5mm. The installation height of the support tube shall be adjusted based on the horizontal plane of the water retaining tube ring plate. After the support tube is positioned, the pads shall be evenly inserted between the water retaining tube and the storage tube. After the water retaining tube and the support tube are connected by ring welding, the elevation of the water retaining tube ring plate shall be checked and adjusted to the design value again, and then the pads shall be removed.

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