CN111243775A

CN111243775A - Disposal method with radioactive device for nuclear power plant, system and product

Info

Publication number: CN111243775A
Application number: CN202010076983.2A
Authority: CN
Inventors: 刘省勇; 张文利; 谢建华; 何英勇
Original assignee: China General Nuclear Power Corp; CGN Power Co Ltd; Daya Bay Nuclear Power Operations and Management Co Ltd; Lingdong Nuclear Power Co Ltd; Guangdong Nuclear Power Joint Venture Co Ltd; Lingao Nuclear Power Co Ltd
Current assignee: China General Nuclear Power Corp; CGN Power Co Ltd; Daya Bay Nuclear Power Operations and Management Co Ltd; Lingdong Nuclear Power Co Ltd; Guangdong Nuclear Power Joint Venture Co Ltd; Lingao Nuclear Power Co Ltd
Priority date: 2020-01-23
Filing date: 2020-01-23
Publication date: 2020-06-05
Anticipated expiration: 2040-01-23
Also published as: CN111243775B

Abstract

A disposal method, a disposal system and a disposal product for a nuclear power station with a radioactive device are disclosed, the method comprises a disassembling step, a cutting and sorting step, a decontamination step and a smelting step, the disassembling step is used for disassembling the radioactive device to be disposed to obtain each part with the radioactive device to be disposed, the cutting and sorting step is used for cutting and sorting according to preset specification and size corresponding to each part to obtain parts with corresponding specification and size, the decontamination step is used for decontaminating the parts with corresponding specification and size to obtain corresponding materials, the smelting step is used for smelting reusable metals in the materials, and solidification treatment is carried out on the reusable metals in the materials. Volume reduction treatment of radioactive contaminated devices in the nuclear power station is achieved through the disassembling step and the cutting and sorting step, and occupation of space is reduced. Through the decontamination step and the smelting step, the material is reused, and the big problem that the radioactive polluted device is difficult to treat is solved.

Description

Disposal method with radioactive device for nuclear power plant, system and product

Technical Field

The invention relates to the technical field of nuclear power, in particular to a disposal method, a disposal system and a disposal product with a radioactive device for a nuclear power station.

Background

The spent fuel framework is a device for storing spent fuel assemblies, new fuel assemblies, control rod assemblies and damaged fuel assemblies which are discharged from a nuclear power plant reactor core. The neutron absorption material of the early spent fuel grillwork is cadmium metal, and the size of the sleeve is large, so that 36 fuel assemblies can be accommodated. The structure of the device is shown in figure 1 and mainly comprises a lower supporting plate, an upper supporting plate, a coaming, a sleeve, a supporting leg, a connecting fastener and the like. The novel spent fuel grillwork adopts aluminum-based boron carbide as a neutron absorption material, one spent fuel grillwork can hold 56 groups of fuel assemblies, and in order to enable a spent fuel pool to store more spent fuel assemblies, part of power plants reform the spent fuel pool, and the old cadmium spent fuel grillwork is replaced by a new aluminum-based boron carbide grillwork (high-density grillwork). The replaced spent fuel grillwork has certain radioactivity because the replaced spent fuel grillwork is used in a spent fuel pool for a long time, and needs to be disposed as radioactive waste.

The original disposal scheme is as follows: the method comprises the steps of firstly washing and decontaminating the spent fuel grillwork by using high-pressure water in a refueling water pool, then drying, finally packaging and marking the spent fuel grillwork by using plastic tarpaulin, and then transferring the spent fuel grillwork to a radioactive machine maintenance, decontamination and storage workshop for storage. The main disadvantages of this solution are as follows: the national environmental protection agency of people's republic of China stipulates that the storage of radioactive solid wastes in No. 25, the radioactive waste treatment, storage and disposal permit management method, requires the establishment of corresponding temporary waste storage facilities, and the maximum storage life is 5 years, and the original technical scheme needs to adopt other schemes for disposal after reaching the temporary storage life; secondly, by adopting the scheme of temporary storage disposal, 20 spent fuel grills and packaging materials thereof occupy about 300m³The space of the radioactive machine maintenance, decontamination and storage factory building is occupied, and daily maintenance operation of the area is seriously influenced; and thirdly, although the scheme adopts decontamination modes such as high-pressure water washing and the like, the spent fuel grillwork still has certain radioactivity, and the risk of potential irradiation on workers in the area exists.

Disclosure of Invention

The invention mainly solves the technical problem of realizing volume reduction treatment and material reuse of a radioactive pollution device in a nuclear power station.

According to a first aspect, a treatment method with a radioactive device for a nuclear power plant in an embodiment comprises:

disassembling: disassembling the device to be treated with radioactivity to obtain each part of the device to be treated with radioactivity;

cutting and sorting: cutting and sorting according to the preset specification and size corresponding to each part to obtain parts with corresponding specification and size;

a decontamination step: decontaminating the parts with corresponding specifications and sizes to obtain corresponding materials;

a smelting step: and smelting reusable metal in the material, and solidifying non-reusable metal in the material.

In one possible implementation, the method further comprises a radioactive dose detection step;

the radioactive dose detection step includes:

a measurement step: measuring the surface dose rate and sampling and analyzing the nuclide species to obtain a dose detection result;

a step of classification and identification: and marking and classifying according to a preset dose horizontal classification table based on the dose detection result.

In one possible implementation, the radioactive dose detection step is performed before the disassembly step;

the disassembling step includes:

and according to the marking and classifying result of the device to be treated with radioactivity, remotely disassembling the device to be treated with radioactivity with high dose, and disassembling the device to be treated with radioactivity with low dose in a short distance.

In one possible implementation, the step of detecting the radioactive dose is performed before the step of melting, and the step of classifying includes:

and classifying the metals in the material into reusable metals and non-reusable metals according to a preset dose level classification table based on a dose detection result.

In one possible implementation, the disassembling step includes:

and disassembling the bolt, the support legs, the coaming, the sleeve and the upper and lower support plates with the radioactive devices to be treated by using disassembling equipment in a disassembling station with a ventilation arrangement device.

In one possible implementation, the device to be disposed of with radioactivity is a spent fuel grid, and the cutting and sorting step includes:

in a cutting station with a local exhaust ventilation device, a vacuum suction device, a cutting debris collection device and an air detection device, cutting a sleeve of a spent fuel framework by using a laser cutting method according to preset cutting power and linear speed;

and sorting the cadmium plate obtained after cutting.

In one possible implementation, the decontamination step comprises:

the decontamination is performed using a chemical decontamination method, an ultrasonic decontamination method, and/or a laser decontamination method.

In one possible implementation, the smelting step includes:

and obtaining a material obtained by smelting reusable metal in the material, and processing the material into a product.

According to a first aspect, a disposal system with radioactive means for a nuclear power plant in one embodiment comprises a disassembling module, a cutting and sorting module, a decontamination module and a melting module;

the disassembling module is used for disassembling the device to be treated with radioactivity to obtain each part of the device to be treated with radioactivity;

the cutting and sorting module is used for cutting according to the preset specification and size corresponding to each part and sorting to obtain parts with corresponding specification and size;

the decontamination module is used for decontaminating the parts with the corresponding specification and size to obtain corresponding materials;

the smelting module is used for smelting reusable metal in the materials and solidifying non-reusable metal in the materials.

According to a first aspect, a disposal product with a radioactive device for use in a nuclear power plant in an embodiment comprises:

a memory for storing a program;

a processor for implementing the method as claimed in any one of the above by executing the program stored in the memory.

The embodiment of the invention has the following beneficial effects:

a disposal method with a radioactive device for a nuclear power station comprises a disassembling step, a cutting and sorting step, a decontamination step and a smelting step, wherein the disassembling step is used for disassembling the radioactive device to be disposed to obtain each part with the radioactive device to be disposed, the cutting and sorting step is used for cutting and sorting according to the preset specification and size corresponding to each part to obtain parts with corresponding specification and size, the decontamination step is used for decontaminating the parts with corresponding specification and size to obtain corresponding materials, the smelting step is used for smelting reusable metals in the materials, and the solidification treatment is carried out on the reusable metals in the materials. Through the disassembly step and the cutting and sorting step, the volume reduction treatment of the radioactive contaminated device in the nuclear power station is realized, the occupation of the radioactive contaminated device to the space is reduced, the radioactive contaminated device is further concentrated, and the potential irradiation risk of the radioactive contaminated device to workers is avoided. Through the decontamination step and the smelting step, the waste treatment cost is reduced, the material reuse is realized, and the economic and social benefits are further increased.

Drawings

Fig. 1 is a schematic structural diagram of a spent fuel lattice according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a disposal method with radioactive equipment for a nuclear power plant in accordance with an embodiment of the present invention;

FIG. 3 is a schematic diagram of another disposal method with radioactive devices for a nuclear power plant in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view of a long rod tool for measuring surface dosage of a cannula according to an embodiment of the present invention;

FIG. 5 is a schematic illustration of a disassembly process according to an embodiment of the present invention;

FIG. 6 is a schematic view of a casing disassembling apparatus according to an embodiment of the present invention;

FIG. 7 is a disassembled view of a casing according to an embodiment of the present invention;

FIG. 8 is a disassembled schematic view of another sleeve of the embodiment of the present invention;

FIG. 9 is a schematic view of a sleeve structure according to an embodiment of the present invention;

FIG. 10 is a cut-away view at A of FIG. 9 according to an embodiment of the present invention;

FIG. 11 is a cutaway view at C of FIG. 9 of an embodiment of the present invention;

FIG. 12 is a cutaway view at B-B of FIG. 9 of an embodiment of the present invention;

fig. 13 is a schematic diagram of a cutting workshop arrangement according to an embodiment of the present invention.

FIG. 14 is a schematic diagram of a laser-cut entity according to an embodiment of the present invention;

FIG. 15 is a schematic diagram of the cutting entity at A in FIG. 14 according to an embodiment of the present invention;

FIG. 16 is a schematic view of a laser-cut model of an embodiment of the present invention;

FIG. 17 is a schematic view of another cutting booth according to an embodiment of the present invention;

fig. 18 is a schematic view of a casing cutting process according to an embodiment of the present invention.

FIG. 19 is a diagram of a cutting and flattening apparatus according to an embodiment of the present invention;

FIG. 20 is a schematic view of a process flow for implementing a backup plate/fence cutting operation according to an embodiment of the present invention;

FIG. 21 is a schematic view of a support plate for plasma cutting according to an embodiment of the present invention;

FIG. 22 is a schematic flow chart of another handling method with radioactive device for nuclear power plant in accordance with an embodiment of the present invention;

FIG. 23 is a schematic diagram of a disposal system having a radioactive device for use in a nuclear power plant in accordance with an embodiment of the present invention;

fig. 24 is a schematic structural diagram of another disposal system with a radioactive device for a nuclear power plant according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). (may be omitted as the case may be)

As described in the background art, the prior art disposal methods for devices with radioactive contamination in a nuclear power plant, such as spent fuel grids, are all transferred to radioactive machine maintenance, decontamination and storage plants for storage, but storage is not a practical problem, devices with radioactive contamination still need to be properly disposed of, as nuclear power continues to develop, more and more nuclear power plants or equipment gradually enter a decommissioning stage, the technology for disposing radioactive contaminants in the field of decommissioning of nuclear power facilities is not mature, the inventor minimizes secondary wastes (including tools) based on a waste minimization principle, realizes cleaning and control of wastes, and considers that the equipment structures in the nuclear power plants are large, so that the devices with radioactive contamination need to be disposed first, after the devices with radioactive contamination are disassembled, classification treatment is performed according to the dose level of radioactive substances contained in the disassembled materials, the reusable metal is processed into a product, and the non-reusable metal is cured.

Example one

Referring to fig. 2, a schematic diagram of a disposal method with radioactive apparatus for a nuclear power plant according to an embodiment of the present invention includes a disassembling step S10, a cutting and sorting step S20, a decontamination step S30, and a melting step S40, and a radioactive dose detection step S50 may also be included in one possible implementation manner. This will be explained in detail below.

In the embodiment of the present invention, the radioactive device is described by taking a spent fuel rack as an example, and it is obvious to those skilled in the art that the radioactive contaminated device in a nuclear power plant can be disposed by using the disposal method with the radioactive device for a nuclear power plant of the present invention. The grills are used to refer to spent fuel grills with radioactivity to be treated.

As shown in fig. 3, before performing the disassembling step S10, the transferring step S00 may be optionally performed, and the transferring step S00: the spent fuel grids to be treated with radioactivity are transferred from the storage area to the corresponding working area to be disassembled S10, or the spent fuel grids to be treated with radioactivity can be directly taken out from the pool to be transferred to the corresponding working area.

In the embodiment of the invention, a transfer trolley can be used for carrying, or a crane, a forklift and the like can be used for hoisting and transferring.

A disassembly step S10: and disassembling the device to be treated with radioactivity to obtain each part of the device to be treated with radioactivity.

As shown in fig. 3, the radioactive dose detection step S50 may be optionally performed before the dismantling step S10, and it should be noted that the radioactive dose detection step S50 in fig. 3 is not limited to be performed only before the dismantling step S10, and may be performed during the steps of dismantling step S10, cutting sorting step S20, decontamination step S30, and melting step S40, or after or before the dismantling step S10, cutting sorting step S20, decontamination step S30, and melting step S40, which is not specifically limited in this respect. Radioactive dose detection step S50: and detecting the surface dose rate of the spent fuel grillwork, and sampling and analyzing the species of nuclides to obtain a dose detection result. And then marking and classifying according to a preset dose horizontal classification table based on a dose detection result. When the spent fuel grillwork is transferred out of the pool, the actual dosage level and the nuclide type of the spent fuel grillwork cannot be known according to data of the spent fuel grillwork after the spent fuel grillwork is discharged out of the pool, so the surface dosage rate of a sleeve needs to be measured and the nuclide type needs to be sampled and analyzed before the spent fuel grillwork is disassembled, a subsequent treatment process, such as decontamination, solution control, waste classification treatment and the like, is determined after the radiation level is obtained, classification marks can be carried out according to GB27742-2011 radioactive nuclide activity concentration in materials which can be free from radiation protection supervision, GB/T17567-2009 clean solution control level of iron, steel, aluminum, nickel and copper recycling and recycling of nuclear facilities, for example, the spent fuel grillwork is further divided into tube-free metal waste, recyclable metal waste and high-radioactive waste according to the radioactivity level and the pollution degree of the waste. And adopts different treatment and disposal modes according to corresponding regulations. For example, the spent fuel framework is divided into pipe-free metal waste, and the spent fuel framework can be directly processed; the spent fuel framework is divided into reusable metal wastes, and then the spent fuel framework can be further treated (cut, decontaminated and smelted); when the spent fuel grillwork is divided into high radioactive wastes, the spent fuel grillwork can be smelted and solidified.

In one possible embodiment, the radioactive dose detection step S50 is performed before the dismantling step S10, and the dismantling step S10 includes: and according to the marking and classifying result of the device to be treated with radioactivity, remotely disassembling the device to be treated with radioactivity with high dose, and disassembling the device to be treated with radioactivity with low dose in a short distance. The surface dose of the spent fuel grid sleeve is measured in a horizontal position, under the condition that the dose rate of the outer surface of the spent fuel grid is high, as shown in fig. 4, a disassembling robot long rod tool is supposed to be adopted for detection, and under the condition that the dose rate is low, a person can be adopted for detection in a mode of matching a movable shielding device.

In one possible embodiment, the disassembling step S10 includes:

and disassembling the bolt, the support legs, the coaming, the sleeve and the upper and lower support plates with the radioactive devices to be treated by using disassembling equipment in a disassembling station with a ventilation arrangement device. In order to avoid the diffusion risk of radioactive dust and aerosol, a grid disintegration station with the ventilation and local arrangement function is built. As shown in fig. 5, fig. 5 is one of the possible disassembling flow steps, which includes performing on-site cleaning, building a disassembling station, equipping a ventilation arrangement device to the disassembling station, then hoisting the framework onto a workbench, placing the framework, performing dose detection, disassembling the bolts, the legs, the coaming, the sleeves, the upper and lower support plates of the framework, collecting and storing the loose parts pulled down by disassembling the bolts and the legs, performing large-piece cutting on the support plates and the coaming, and individually cutting the sleeves, and it should be noted that the disassembling step S10 is not limited to that shown in fig. 5, and fig. 5 is only an indication of one possible implementation manner. The specific disassembly of the grillwork can adopt the following two schemes:

scheme one

Considering that there are radioactive dust and aerosol diffusion risk in the spent fuel framework disassembling process, set up ventilation office row device at the disassembling station, disassemble the work and mainly include: disassembling preparation: the intelligent disassembling robot is used for disassembling in a short distance according to a received instruction, can be provided with personnel protection and a movable shielding device for instruction control, and further comprises bolt disassembling equipment, a special tool and a field cleaning tool. As in fig. 1 and 6, after transporting the grillage to corresponding workstation, disassemble by the intelligence disassembly robot, including disassembling two bounding walls: the adjustable shelf comprises a coaming connecting bolt (M20), an adjustable shelf support leg at the bottom of the shelf and a coaming disassembling structure. The spot-welded bolt is screwed off mainly by using bolt disassembling equipment (a movable support frame, a bolt pneumatic wrench, a driving head and the like), and the support bolt is disassembled by using a special long rod tool. As shown in fig. 7, the grid bushing is disassembled: includes removing the sleeve coupling nut (M64) using a bolt removal mechanism, then withdrawing the sleeve from the grid, and transferring the sleeve to the temporary sleeve storage area using a mobile forking device. After each sleeve pipe is detached in sequence, the rest two enclosing plates and the upper supporting plate and the lower supporting plate are detached, and the spare parts are placed in the temporary storage area through a factory crane or forking equipment.

It should be noted that bolt disassembling is planned to adopt intelligent robot close range remote operation, adopts simple structure to operate safe convenient equipment to reduce the production of secondary waste, sets up waste collection facility in the operating area of disintegration station, avoids causing secondary pollution, and can carry out radioactive dose detection step S50 at the disassembly in-process.

Scheme two

Considering the mechanical dismantling of the spent fuel grillwork, a remote control machine tool can be adopted, as shown in fig. 8, according to preset logic control, the machine tool is operated remotely to prevent the spent fuel grillwork from being directly placed on a machine tool base by a crane at a dismantling station to be positioned and clamped, the machine tool adopts a gate type structure, and a milling head, a bolt tightening mechanism, a cutting monitoring system, a base, a walking structure, a remote control system and the like are configured. The milling head of the cutting machine tool mills the M20 bolt (anti-loosening in spot welding) on the enclosing plate, and then sequentially splits the grillwork to obtain each part, such as the bolt with the radioactive device to be treated, the supporting legs, the enclosing plate, the sleeve, the upper supporting plate and the lower supporting plate.

Optionally, after disassembling the spent fuel grillwork, using a dose detection tool to classify wastes according to dose levels, loading 200L metal barrels with over-standard dose (more than or equal to 2mSv/h), transporting to QS/QT library for super compression through a transfer shielding container, and then loading 400L metal barrels for cement solidification. The cutting and sorting step S20, the decontamination step S30 and the smelting step S40 are carried out on the small dosage.

Cutting and sorting step S20: and cutting according to the preset specification and size corresponding to each part, and sorting to obtain the parts with corresponding specification and size.

Due to the complex structure of the grid casing, the casing structure is a three-layer structure composed of stainless steel and cadmium, as shown in fig. 9, fig. 10, fig. 11 and fig. 12, cadmium is a toxic heavy metal, in order to recycle different metal materials, a cutting station with the functions of air tightness and cutting debris collection is developed for the grid, the grid casing is cut in an optical fiber laser cutting mode, and then the grid casing is flattened and sorted. As the upper support plate, the lower support plate and the coaming of the spent fuel grillwork have large sizes and the thickness reaches 50mm, the parts can be cut and disintegrated by adopting a plasma cutting mode in the cutting station.

In one possible implementation manner, as shown in fig. 13, the cutting and sorting step S20 includes: in a cutting station with a local row ventilation device, a vacuum suction device, a cutting debris collection device and an air detection device, a laser cutting method is used for cutting a sleeve of a spent fuel grid frame according to preset cutting power and linear speed, cadmium plates obtained after cutting are sorted, and dust, aerosol and the like generated in the cutting process are filtered through a ventilation local row and then discharged to a ventilation system of a factory building.

In the embodiment of the invention, the whole metal cutting process can be divided into two modes of cold cutting and hot cutting. The cold cutting is realized by adopting mechanical processing or other cutting modes, and high temperature is not generated in the cutting process; thermal cutting is a method of melting or gasifying a material to separate the material by means of high temperature of heat energy. The relatively mature cold cutting modes in industrial production comprise mechanical cutting, water cutting and the like. When radioactive metal is cut, introduction of liquid is avoided as much as possible to prevent radioactive waste liquid from being generated, and a coolant is required to be introduced to cool a workpiece in the cutting process of cold cutting; meanwhile, in the mechanical stamping and cutting method commonly used in mechanical cutting, the direct contact between the cutting tool and the workpiece can cause the rapid abrasion of the cutting tool, and the cutting tool needs to be replaced periodically; and meanwhile, the method also faces the limiting factors of difficult clamping and fixing, large workpiece deformation and the like. The sleeve pipe occupies a large proportion of the workload of disassembling the grillwork, and meanwhile, the sleeve pipe is internally provided with a highly toxic cadmium material, the cutting of the sleeve pipe needs to consider the separation of cadmium, and the cadmium pollution of air or dust generated in the operation process is avoided. The sleeve is made of three layers of thin-wall metal, large smoke or dust is avoided during processing and separation, cold cutting is the best choice, and through research and analysis, the cold cutting is difficult to cut, a cutter is cooled, the efficiency is low, and the like, and the sleeve is disassembled and processed preferably in a laser cutting and mechanical cutting (two ends of the sleeve). For thick steel plates (enclosing plates, upper and lower supporting plates) and special-shaped tools, cutting is carried out in a plasma mode, and a scrap collecting device and a smoke collecting device are arranged to ensure operation safety. When the spent fuel grillwork is cut, the spent fuel grillwork is cut into parts with certain specification and size according to the requirements of a subsequent treatment process, so that the subsequent detection and disposal operation is facilitated. For example, the maximum size of the metal piece charged into the furnace in the smelting step is 300 mm. Therefore, in the grid cutting process, in order to meet the size requirement of waste preparation, the cutting or compression operation equipment needs to be added, and cutting is carried out according to the preset specification size.

Laser cutting of the cannula is described in detail below.

Firstly, performing laser cutting theoretical analysis, and in order to determine key process parameters of laser cutting and guide the actual cutting process, performing simulation analysis on the laser cutting process by using ANSYS19.0 finite element analysis software (ANSYS 19.0 is more mature in the technology of life and death units, and error reporting and temperature distortion can occur in ANSYS 12). In the modeling section, the physical properties of cadmium metal and 316L stainless steel are defined, and then a three-layer model (0.8mm-0.5mm-2mm) is established in software according to the sandwich structure of the cadmium plate, and considering that the heat affected zone of laser cutting is small while saving time, the length is illustratively 5mm along the cutting direction and 4mm perpendicular to the cutting direction, as shown in fig. 14 and 15, i.e., the plane shown in fig. 15 is cut at a in fig. 14, in the meshing section, because the coordinates of each cell need to be accurately positioned when using the life and death cell judgment, only the regular meshing can be used. Setting of boundary conditions: the heat source was loaded on a stainless steel surface 8mm thick using a gaussian surface heat source power density. The general flow of the overall simulation is as follows: the first calculation is performed after modeling and adding the load. And judging the temperature of the unit according to the calculation result, carrying out life and death unit treatment, and killing the unit with the temperature exceeding the melting point. And after a new model is obtained, moving the heat source, and carrying out next calculation until the whole cutting action is completed. When the cutting speed was 8mm/s (0.48/min), the model after cutting was as shown in FIG. 16. It can be seen that in the middle of the material, since the melting point of cadmium metal is much lower than that of 316L stainless steel, the middle part has a larger cutting width than the other parts. Meanwhile, because the boundary conditions of the two ends of the model along the cutting direction are different from those of the middle part, the cutting width of the model is larger and is suitable for shifting. Furthermore, the cutting simulation analysis at cutting speeds of 12.5mm/s, 15mm/s, 17mm/s, 19mm/s, 21mm/s and 25mm/s was exemplarily performed. Simulation results show that when the laser power and the auxiliary gas flow are fixed, the cutting speed is increased, the efficiency can be improved, the material gasification amount is reduced, and the generation of aerosol and cutting debris is reduced. However, when the cutting speed exceeds 19mm/s, the material may be stuck. According to the research and analysis, the sleeve of the spent fuel lattice can be cut by using a laser cutting method according to the preset cutting power and linear speed, and the better cutting effect can be achieved.

Each spent fuel framework is provided with 36 casings, and the casing cutting is sequentially carried out in batches in consideration of limited field turnover space. As shown in fig. 17, the cutting is performed in the cutting workshop of fig. 17, that is, the cutting is performed in the container sealing workshop, all operations are performed in the container sealing workshop, and personnel control is performed through an operation table outside the container. Every sheathed tube cutting flow can refer to fig. 18, and fig. 18 is the sleeve pipe cutting mode that one of them probably realized, and sleeve pipe location dress card carries out the bottom plate cutting, carries out the horn mouth cutting, or collects bottom plate, horn mouth cutting back, indulges the sleeve pipe and cuts, flattens, cuts and sorts to collect the material after the cutting, transport and keep in. The lattice cutting includes lattice bottom plate cutting, bell mouth cutting, casing pipe longitudinal cutting, casing pipe leveling and cutting, cadmium plate separation and the like, as shown in fig. 19, fig. 19 is a drawing of cutting and flattening equipment according to an embodiment of the present invention, and the equipment is used for cutting and flattening the casing pipe. The used equipment comprises a sleeve transmission and clamping platform, a sleeve end cutting device (milling machine), a sleeve turnover mechanism, a longitudinal cutting machine (laser cutting machine), a sleeve (continuous) leveling device, a cadmium plate sorting mechanism and an auxiliary crane. The end cutting equipment cuts off the cadmium-free parts at the two ends of the sleeve firstly, and then the laser cutting robot cuts the sleeve into an upper part and a lower part from the middle. And the conveying structure conveys the cadmium-containing sheets into flattening/shearing equipment, flattening and cutting the cadmium-containing sheets into sheets of less than 30cm by 30cm, and finally sorting the cadmium sheets. Dust, aerosol and the like generated in the cutting process are filtered by local discharge and then discharged to a ventilation system of a factory building.

Compared with cold cutting, the laser cutting does not need to be in direct contact with a workpiece, the defect that a cutting head of cold cutting equipment needs to be replaced is avoided, and the efficiency is improved while the cost is reduced. Compared with other cutting methods, the laser cutting has the following effects: a) the cutting quality is good, the laser cutting light spot is small, the energy convergence is high, the heat affected zone is small, the better cutting quality can be obtained, meanwhile, the gasified part is less, and the gasification amount of radioactivity and toxic heavy metals can be effectively controlled. b) The cutting efficiency is high, the energy conversion rate of the optical fiber laser cutting is high, the energy density is high, and the cutting speed can be greatly improved. c) The cutting materials are various, and the laser cutting materials are more than flame cutting and plasma arc cutting, and comprise metal, nonmetal, wood, fiber and the like.

The cutting of the grid plates, such as the cutting of the support plates and the fenders, is described in detail below.

Fig. 20 is a schematic diagram of one possible support plate/shroud cutting process, as shown in fig. 20, where each grid includes four shrouds and upper and lower support plates. The coaming is of an L-shaped structure, the length multiplied by the width is about 4120mm multiplied by 1760mm, and the thickness is 10 mm. The upper and lower support plates are 1720mm × 1720mm in thickness and 50mm in total weight, and the total weight is 332kg/655kg respectively. Considering that the thickness of the coaming and the supporting plate is thick, the laser cutting speed is too slow, and a high-power laser is needed, so that the price is high, and therefore a mature and low-price plasma cutting mode is adopted. The plasma cutting apparatus may employ a robot or a cutting machine, as shown in fig. 21. The cutting robot is flexible to operate and has higher applicability, and comprises a robot hand, a base, a plasma cutting head, a plasma power supply, an operation cabinet, an electrical control system, a cutting platform, an auxiliary card installing mechanism and the like. The enclosing plate and the supporting plate are conveyed into the cutting workshop through the transfer trolley and placed on the cutting platform through the auxiliary hoisting tool, the plasma cutting robot can automatically cut the plate, and the plasma cutting technology belongs to the mature technology and is mainly used for cutting thick metal plates. The plasma cutting equipment of the robot mechanism is selected, and is based on mature application and expanded applicability, the cutting equipment not only can cut the grillwork, but also can cut the grillwork operation tool and other metals and even special-shaped materials made of various metal materials, and the radioactive metal processing requirements of the nuclear power plants in gulf of great asia and Australia of mountains can be met to the maximum extent.

Decontamination step S30: and (4) decontaminating the parts with the corresponding specifications and sizes to obtain corresponding materials.

In one possible implementation, the decontamination step S30 includes:

After the spent fuel grillwork is discharged from the pool, the spent fuel grillwork is washed and dried by high-pressure water, and the surface basically has no dust accumulation. However, according to the analysis of the dosage data measured by the effluent pool, the risk that the local dosage exceeds the standard exists in the grid (the dosage of the outer surface is greatly different before and after the pool is flushed, and the internal dosage data is an underwater measured value), and the dosage of the surface is increased or greatly increased after the grid is disassembled into parts. And (3) adopting necessary classification treatment according to the dosage level of the grillwork before disassembly, and carrying out decontamination treatment on parts with higher dosage level in a workshop of a factory decontamination room. The current processing equipment is as follows: the maximum decontamination volume of SBE203BA/SBE204BA/SBE205BA is 1.2m × 1.2m × 1.2m, and chemical decontamination can be carried out; SBE207BA/SBE208BA is an ultrasonic decontamination tank and can be matched with chemical decontamination to realize mechanical decontamination; SBE201BA can be used for cleaning and decontaminating long rods, and the maximum workpiece size is 7.3m multiplied by 0.4 m; SBE213BA is a wash station with a table size of 4.28m 3.28m 0.61m and can carry 1t/m 2. The chemical decontamination, cleaning and drying of the grid parts are completed by utilizing the decontamination equipment and the auxiliary tool. After decontamination, the dosage levels were measured and classified in preparation for subsequent treatment. Considering that partial spare parts may have local hot spots, the project implementation stage adopts advanced decontamination modes such as laser decontamination and the like according to specific situations, so that decontamination efficiency is improved, and waste minimization is realized.

After the decontamination step S30, the radioactive dose detection step S50 may be optionally performed, and the species of the nuclide of the analysis result after the disassembly, cutting, and decontamination of the old grid members may satisfy table 1. When nuclide exemption level and uncontrol level are required, exemption and uncontrol application can be made to a supervision department. Exempt and uncontrolled can be classified as reusable metal. For metal wastes which cannot be exempted or controlled directly, the method of smelting decontamination can be further adopted for decontamination. The scrap metal meeting the level of solution control can be sent to a common steel smelting plant for smelting.

TABLE 1

Note: a. the level of solid matter decontrol and the level of exemption of bulk solid matter; b. the exemption level of small batches of solid matter, usually applied to practice with radioactive substances on a small scale, is of the order of up to a few dimensionless tons.

And judging whether different parts of the old framework are surface pollution or bulk (including activation) pollution according to the source of radioactive pollutants on the framework and the sampling analysis result, and further determining a subsequent detailed treatment scheme. Radioactive metal waste which belongs to surface pollution can be subjected to solution control by adopting a physical or chemical cleaning decontamination method; radioactive metal waste contaminated by bodies (including activated) can be treated by melting decontamination or by solidification. Dose guidelines for exemption or resolution according to the rules of radioactive waste classification: in all cases where this is reasonably foreseen, the exempt practice or source (or the controlled substance) will be such that any individual will receive an effective dose on the order of 10 μ Sv or less within a year, and will receive an effective dose of no more than 1ms Sv, even in the unlikely event of a low probability of unexpected disadvantage.

A melting step S40: and smelting reusable metal in the material, and solidifying non-reusable metal in the material.

In one possible implementation, the radioactive dose detection step S50 is performed before the melting step S40, and the classification and identification step includes:

As shown in fig. 22, before smelting, after decontamination, radioactive dosage detection is performed, high dosage and low dosage are obtained according to detection results, cement solidification is performed on the high dosage, a waste barrel is placed to be operated to a waste disposal site, the low dosage is sent to a smelting treatment plant to be treated to obtain steel ingots, the steel ingots are sent to be manufactured by utilization equipment to obtain corresponding shielding materials or waste barrels, and the corresponding shielding materials or waste barrels are returned to a nuclear power plant to be recycled.

In one possible implementation manner, the smelting step S40 includes: and obtaining a material obtained by smelting reusable metal in the material, and processing the material into a product.

In the embodiment of the invention, the reusable metal is low-dose metal or exempt or uncontrolled metal, and the radioactivity of the reusable metal meets the requirement of materials and can be processed into a product. The non-reusable metal is a high dose metal or a metal that is not exempt or uncontrollable.

In the embodiment of the invention, about 90.5% of the material in the spent fuel grillwork is 316L stainless steel, the spent fuel grillwork can be directly cast into a shielding container or a plate after smelting, and the plate can be made into a metal barrel or other containers for nuclear power plant production after rolling and machining. Illustratively, non-reusable metal is loaded into 200L metal drums, transported through transport shielded containers to QS/QT reservoir for super compression, and then loaded into 400L metal drums for cement curing.

The embodiment of the invention has the following characteristics: the spent fuel framework is firstly disassembled, cut, decontaminated and smelted in China, so that the volume reduction treatment of the spent fuel framework and the reuse of most materials are realized; disassembling the radioactive spent fuel framework by using a framework disassembling station with a ventilation local arrangement function; cutting and sorting the grid parts by adopting a cutting station with air tightness and cutting debris collection functions; removing radioactive substances stained on the spent fuel grillwork by adopting an ultrasonic wave and chemical decontamination mode; and reusing the metal material subjected to the solution control by adopting a smelting mode.

Solves the following major technical problems: the spent fuel grillwork has a complex structure, has certain radioactivity after being used, and lacks volume reduction treatment experience at home and abroad. The invention adopts the processes of disassembly, cutting, decontamination, dosage detection, smelting and the like to realize the volume reduction treatment and material reuse of the spent fuel grillwork; the framework casing is a composite three-layer structure consisting of 2mm/0.8mm stainless steel and 0.5mm cadmium material, has poor structural rigidity, and how to realize the sorting and recycling of the stainless steel and the cadmium material; cadmium materials are toxic heavy metals, which may cause environmental pollution, and insufficient protection measures will cause serious industrial safety accidents. The grid work station is provided with a local exhaust system, a vacuum suction device, an air monitoring system and the like, so that the cutting is ensured not to cause environmental pollution; according to the national regulation, radioactive metal materials can be used in a controlled manner after decontamination and other operations are carried out and the national decontrol standard is reached, for example, the radioactive metal materials are applied to mining machinery, but the spent fuel grid material is mainly stainless steel, and after the decontrol and smelting treatment are carried out, the final volume reduction treatment effect is determined by how to use the spent fuel grid material in a controlled manner. The invention reprocesses the stainless steel material after the smelting treatment, processes the metal barrel or shielding material for containing radioactive wastes in the nuclear power plant, realizes the controlled use and finally realizes the capacity reduction treatment of the spent fuel grillwork.

The application of the invention can generate economic and social benefits: the core device such as the cutting station can be used for cutting treatment of the spent fuel grillwork and can also be used for treating radioactive waste metal generated in the daily operation and maintenance process of a power plant. Wherein part of the materials can be recycled, thereby bringing high net benefit and saving waste treatment cost. The invention can bring greater social benefit. With the continuous development of nuclear power, more and more nuclear power plants or equipment gradually enter the retirement stage. The radioactive waste metal treatment idea can be provided, and certain reference and guiding significance is provided for the formulation of the decommissioning scheme of the subsequent nuclear power plant and the selection of the decommissioning operation equipment.

Example two

Referring to fig. 23, an embodiment of the present invention provides a disposal system with radioactive devices for a nuclear power plant, including a disassembling module 101, a cutting and sorting module 102, a decontamination module 103, and a melting module 104;

the disassembling module is used for disassembling the device to be treated with radioactivity to obtain each part of the device to be treated with radioactivity.

The cutting and sorting module is used for cutting and sorting according to the preset specification and size corresponding to each part to obtain the parts with corresponding specification and size.

The decontamination module is used for decontaminating the parts with the corresponding specification and size to obtain corresponding materials.

In one possible implementation manner, as shown in fig. 24, the radioactive dose detection module 105 is further included, it should be noted that the radioactive dose detection module in fig. 24 is not limited to be executed before the melting module 104, but may be executed during the steps of disassembling the module 101, the cutting and sorting module 102, the decontamination module 103 and the melting module 104, or executed after or before the disassembling module 101, the cutting and sorting module 102, the decontamination module 103 and the melting module 104, and the present invention is not particularly limited thereto.

Those skilled in the art will appreciate that all or part of the functions of the various methods in the above embodiments may be implemented by hardware, or may be implemented by computer programs. When all or part of the functions of the above embodiments are implemented by a computer program, the program may be stored in a computer-readable storage medium, and the storage medium may include: a read only memory, a random access memory, a magnetic disk, an optical disk, a hard disk, etc., and the program is executed by a computer to realize the above functions. For example, the program may be stored in a memory of the device, and when the program in the memory is executed by the processor, all or part of the functions described above may be implemented. In addition, when all or part of the functions in the above embodiments are implemented by a computer program, the program may be stored in a storage medium such as a server, another computer, a magnetic disk, an optical disk, a flash disk, or a removable hard disk, and may be downloaded or copied to a memory of a local device, or may be version-updated in a system of the local device, and when the program in the memory is executed by a processor, all or part of the functions in the above embodiments may be implemented.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.

Claims

1. A disposal method with radioactive means for a nuclear power plant, characterized by comprising:

cutting and sorting: cutting according to the preset specification and size corresponding to each part, and sorting to obtain parts of each corresponding specification and size;

2. The method of claim 1, further comprising a radioactive dose detection step;

the radioactive dose detection step includes:

3. The method of claim 2, wherein the radioactive dose detection step is performed prior to the disassembly step;

the disassembling step includes:

4. The method of claim 2, wherein the step of detecting radioactive doses is performed before the step of melting, and wherein the step of categorizing includes:

5. The method of claim 1, wherein the disassembling step comprises:

6. The method of claim 1, wherein the device with radioactivity to be disposed of is a spent fuel grid, and the cutting and sorting step comprises:

and sorting the cadmium plate obtained after cutting.

7. The method of claim 1, wherein the decontaminating step comprises:

8. The method of claim 1, wherein the smelting step comprises:

9. A disposal system with radioactive devices for a nuclear power plant, characterized by comprising a disassembling module, a cutting and sorting module, a decontamination module and a melting module;

the cutting and sorting module is used for cutting and sorting according to the preset specification and size corresponding to each part to obtain parts with corresponding specification and size;

10. A disposal product having a radioactive device for use in a nuclear power plant, comprising:

a memory for storing a program;

a processor for implementing the method of any one of claims 1-8 by executing a program stored by the memory.