阅读说明：本技术 一种放射性废物-包壳固化体及其制备方法和放射性废物的整备方法 (Radioactive waste-cladding solidified body and preparation method thereof and preparation method of radioactive waste ) 是由 李建军 李子沐 于 2020-07-20 设计创作，主要内容包括：本发明提供了一种放射性废物-包壳固化体及其制备方法和放射性废物的整备方法,属于放射性废物处理及整备技术领域。本发明提供的放射性废物-包壳固化体,包括芯体和包裹在所述芯体表面的壳层,其中,所述芯体的制备原料包括放射性废物,所述壳层的材质为玻璃。本发明以玻璃作为壳层包裹在芯体表面,芯体被完全包裹在壳层内部,不会与外部环境接触,较现有放射性废物与玻璃基材混合熔融的玻璃固化方法相比,可以大大降低芯体的浸出率,甚至可以达到放射性浸出率为零的效果；同时可以提高包容率,同样多的玻璃基材包容的放射性废物质量相比现有的玻璃固化方法大大增大,可以大大降低处理费用。(The invention provides a radioactive waste-cladding solidified body and a preparation method thereof and a preparation method of radioactive waste, belonging to the technical field of radioactive waste treatment and preparation. The radioactive waste-cladding solidified body comprises a core body and a shell layer wrapped on the surface of the core body, wherein the core body is prepared from radioactive waste, and the shell layer is made of glass. The invention takes the glass as the shell to wrap the surface of the core body, the core body is completely wrapped in the shell and can not contact with the external environment, compared with the existing glass solidification method of mixing and melting the radioactive waste and the glass substrate, the leaching rate of the core body can be greatly reduced, and even the effect of zero radioactive leaching rate can be achieved; meanwhile, the containment rate can be improved, the quality of radioactive wastes contained by the same amount of glass substrates is greatly increased compared with that of the conventional glass curing method, and the treatment cost can be greatly reduced.)

1. The radioactive waste-cladding solidified body comprises a core body and a shell layer wrapped on the surface of the core body, wherein the core body is prepared from radioactive waste, and the shell layer is made of glass.

2. The radioactive waste-clad solidified body as claimed in claim 1, wherein the core has a particle size of 0.2 to 150 mm.

3. The radioactive waste-clad solidified body as claimed in claim 2, wherein the thickness of the clad layer is 0.2 to 10 mm.

4. The radioactive waste-clad solidified body of claim 1, wherein the glass comprises a silicate glass, a borate glass, or a phosphate glass.

5. The radioactive waste-enclosure solidified body according to any one of claims 1 to 4, wherein the radioactive waste includes radioactive liquid waste and/or radioactive solid waste.

6. The radioactive waste-cladding solidified body according to claim 5, wherein the radioactive liquid waste is subjected to a first pretreatment including one or more of concentration, drying, calcination and incineration before use.

7. The radioactive waste-cladding solidified body according to claim 5, wherein the radioactive solid waste is subjected to a second pretreatment before use, the second pretreatment including one or more of crushing, incineration and steam reforming.

8. The radioactive waste-clad solidified body as claimed in claim 1, wherein the core is prepared from raw materials further including an additive.

9. The method for preparing the radioactive waste-cladding solidified body as set forth in any one of claims 1 to 8, comprising the steps of:

coating a shell layer on the surface of the core body to obtain a radioactive waste-shell solidified body; the core body is made of radioactive wastes, and the shell layer is made of glass.

10. A method of servicing radioactive waste comprising the steps of:

placing the radioactive waste-cladding solidified body into a metal packaging barrel, pouring and fixing the radioactive waste-cladding solidified body by adopting cement mortar, and then covering and sealing the metal packaging barrel; wherein the radioactive waste-clad solidified body is the radioactive waste-clad solidified body according to any one of claims 1 to 8 or the radioactive waste-clad solidified body prepared by the preparation method according to claim 9.

Technical Field

The invention relates to the technical field of radioactive waste treatment and preparation, in particular to a radioactive waste-cladding solidified body and a preparation method thereof and a preparation method of radioactive waste.

Background

Radioactive waste is a substance that contains or is contaminated with radionuclides, whose concentration or specific activity is greater than the level of cleanliness regulations prescribed by the state department of administration, and is expected to be no longer utilized. Radioactive wastes are classified by their physical properties into gaseous wastes, liquid wastes, and solid wastes, and generally into low-level radioactive wastes, medium-level radioactive wastes, and high-level radioactive wastes according to their radioactive concentration levels. The harm of radioactive waste includes physical toxicity, chemical toxicity, biological toxicity, etc., and some radioactive waste also has the properties of heat, inflammability, explosiveness, harmful gas emission, etc. Therefore, the disposal of radioactive waste is subject to safety principles in the first place, and it is necessary to ensure an acceptable level of protection against human health and environmental impact.

The radioactive waste is prepared before disposal, and is converted into waste objects or waste bags meeting the requirements of the waste receiving standard of the subsequent process, so as to ensure the safety requirements in the processes of carrying, transporting, storing and disposing. At present, the radioactive waste is prepared by a solidification method generally, and specifically, the radioactive waste (such as radioactive solid waste and radioactive liquid waste) is added into a base material and is mixed to form an object which is easy to process (load and unload), stable in physical properties and not easy to disperse. According to different base materials, the method can be divided into cement solidification, asphalt solidification, plastic solidification, glass solidification, ceramic solidification, artificial rock solidification and the like, and the first three methods are suitable for treating the radioactive waste with medium and low water levels and the last three methods are suitable for treating the radioactive waste with high water levels from the economic viewpoint. The techniques that are mature at present and are used industrially are cement curing and glass curing.

Cement setting is a method of setting radioactive waste based on hydration and hydraulic gelation of cement. The cement is used as an inorganic cementing material, a hard cement solidified body is formed after hydration reaction, and the radioactive waste is fixed in the cement solidified body through physical inclusion or chemical combination, so that the aim of solidifying the radioactive waste is fulfilled. However, the method has the defects of low radioactive waste containment rate and high radioactive leaching rate.

The glass solidification is to mix the radioactive wastes with a glass substrate, then to calcine, melt and cast the mixture at a high temperature (900-1200 ℃), and to transform the mixture into a stable glass solidified body after annealing. From the physical and chemical points of view, glass solidification is a dissolution process, and the radioactive waste is dissolved by taking the molten mass of the glass substrate as a solvent, so that the solidification of the radioactive waste is realized. However, the method still has the problems of low inclusion rate (only 15-25 wt%), complex process and high operation and disposal cost.

Disclosure of Invention

The invention aims to provide a radioactive waste-cladding solidified body, a preparation method thereof and a preparation method of the radioactive waste, wherein the radioactive waste is processed into a core body, glass is used as a shell layer to wrap the surface of the core body, the core body is completely wrapped inside the shell layer, the containment rate of the radioactive waste is high, and the leaching rate is low; the radioactive waste-cladding solidified body provided by the invention can realize further preparation and protection of high-level radioactive waste by fixing through cement, and has the advantages of simple operation and low cost.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a radioactive waste-cladding solidified body which comprises a core body and a shell layer wrapped on the surface of the core body, wherein the core body is prepared from radioactive waste, and the shell layer is made of glass.

Preferably, the particle size of the core is 0.2-150 mm.

Preferably, the thickness of the shell layer is 0.2-10 mm.

Preferably, the glass comprises a silicate glass, a borate glass or a phosphate glass.

Preferably, the radioactive waste comprises radioactive liquid waste and/or radioactive solid waste.

Preferably, the radioactive liquid waste is subjected to a first pretreatment before use, the first pretreatment including one or more of concentration, drying, calcination and incineration.

Preferably, the radioactive solid waste is subjected to a second pre-treatment prior to use, the second pre-treatment comprising one or more of crushing, incineration and steam reforming.

Preferably, the raw materials for preparing the core further comprise additives.

The invention provides a preparation method of the radioactive waste-cladding solidified body in the technical scheme, which comprises the following steps:

coating a shell layer on the surface of the core body to obtain a radioactive waste-shell solidified body; the core body is made of radioactive wastes, and the shell layer is made of glass.

The invention provides a preparation method of radioactive waste, which comprises the following steps:

placing the radioactive waste-cladding solidified body into a metal packaging barrel, pouring and fixing the radioactive waste-cladding solidified body by adopting cement mortar, and then covering and sealing the metal packaging barrel; wherein the radioactive waste-clad solidified body is the radioactive waste-clad solidified body in the technical scheme or the radioactive waste-clad solidified body prepared by the preparation method in the technical scheme.

The invention provides a radioactive waste-cladding solidified body which comprises a core body and a shell layer wrapped on the surface of the core body, wherein the core body is prepared from radioactive waste, and the shell layer is made of glass. The invention takes the glass as the shell to wrap the surface of the core body, the core body is completely wrapped in the shell and can not contact with the external environment, compared with the existing glass solidification method of mixing and melting the radioactive waste and the glass substrate, the leaching rate of the core body can be greatly reduced, and even the effect of zero radioactive leaching rate can be achieved; meanwhile, the containment rate can be improved, the quality of radioactive wastes contained by the same amount of glass substrates is greatly increased compared with that of the conventional glass curing method, and the treatment cost can be greatly reduced.

The invention provides a preparation method of the radioactive waste-cladding solidified body, which comprises the following steps: coating a shell layer on the surface of the core body to obtain a radioactive waste-shell solidified body; the core body is made of radioactive wastes, and the shell layer is made of glass. The method provided by the invention is simple to operate, the core body has high containment rate and low leaching rate.

The radioactive waste-cladding solidified body provided by the invention can be further prepared and protected by fixing the radioactive waste-cladding solidified body through cement, particularly the medium and high level radioactive waste, the operation is simple, and the preparation cost of the radioactive waste can be greatly reduced on the premise of meeting the mechanical strength of the solidified body.

Drawings

FIG. 1 is a schematic structural view of a radioactive waste-clad solid according to the present invention;

FIG. 2 is a schematic structural view of a prefabricated two-piece glass shell for use in the preparation of a radioactive waste-cladding solidified body according to the present invention;

FIG. 3 is a schematic structural view of a prefabricated hollow glass shell for use in the preparation of a radioactive waste-clad solid according to the present invention;

in the figure, 1-core body, 2-glass shell layer, 3-two-petal glass shell body and 4-hollow glass shell body;

fig. 4 is a flow chart of the present invention for preparing and preparing a radioactive waste-clad solidified body.

Detailed Description

The invention provides a radioactive waste-cladding solidified body, which comprises a core body and a shell layer wrapped on the surface of the core body, wherein the core body is prepared from radioactive waste, and the shell layer is made of glass.

The radioactive waste-cladding solidified body provided by the invention comprises a core body, wherein the core body is prepared from raw materials comprising the radioactive waste. In the present invention, the particle size of the core is preferably 0.2 to 150mm, more preferably 0.5 to 100mm, still more preferably 1 to 50mm, and still more preferably 2 to 10 mm.

The radioactive concentration level of the radioactive waste is not specially limited, the radioactive waste can be placed at a low level, a middle level and a high level, the radioactive waste is particularly suitable for the radioactive waste at the middle level and the high level, the containment effect is good, the radioactive leaching rate is low, and even the effect that the radioactive leaching rate is zero can be achieved; specifically, the radioactive concentration of low, medium and high levels of radioactive waste can be divided by reference to art-standard divisions.

In the present invention, the radioactive waste preferably includes radioactive liquid waste and/or radioactive solid waste. The source of the radioactive liquid waste and the radioactive solid waste is not particularly limited, and any radioactive liquid waste and radioactive solid waste to be treated can be used; specifically, the radioactive liquid waste can be waste water and organic waste liquid containing or polluted by radioactive nuclides, such as high-level radioactive waste liquid or medium-low level radioactive waste liquid generated by post-treatment of spent fuel, radioactive waste organic solvent (such as TBP extractant), waste oil, decontamination solution, and the like; the radioactive solid waste can be solid waste containing or polluted by radioactive nuclides, such as radioactive waste resin, polluted waste working clothes, decontamination cotton yarn and the like.

In the invention, the radioactive liquid waste is preferably subjected to a first pretreatment before use, the first pretreatment preferably comprises one or more of concentration, drying, calcination and incineration, and a proper process is selected according to actual needs, for example, the radioactive liquid waste can be sequentially subjected to concentration, drying and calcination before use, or can be directly calcined or incinerated; specifically, the calcination is preferably performed under high-temperature anaerobic conditions to achieve sufficient pyrolysis of long-chain organic matter, and the incineration is preferably performed under oxygen sufficient conditions to achieve complete combustion. In the present invention, the concentration in the first pretreatment is preferably performed by an MVR evaporation concentration process. The present invention has no special limitation on the specific operation conditions of concentration, drying, calcination and incineration in the first pretreatment, and can adopt the existing mature process and equipment according to the characteristics of the radioactive liquid waste. In the present invention, after the first pretreatment, a granular waste (inorganic salt substance, referred to as a first granular waste) is obtained. In the present invention, the first pretreatment may remove a solvent (e.g., moisture) and organic matter from the radioactive liquid waste, and may achieve volume reduction and stabilization of the radioactive liquid waste.

In the invention, the radioactive solid waste is preferably subjected to second pretreatment before use, the second pretreatment preferably comprises one or more of crushing, incineration and steam reforming, and a proper process is selected according to actual needs, for example, the radioactive solid waste can be subjected to incineration or steam reforming before use, or can be crushed to obtain a material with a proper particle size according to needs. The present invention has no special limitation on the specific operating conditions of crushing, incineration and steam reforming in the second pretreatment, and can be carried out by adopting the existing mature process and equipment according to the characteristics of radioactive solid wastes. In the present invention, after the second pretreatment, a granular waste (inorganic salt substance, referred to as a second granular waste) is obtained. In the invention, the second pretreatment can remove organic matters and other components in the radioactive solid waste, and can realize volume reduction and stabilization treatment of the radioactive solid waste.

In the present invention, the material of the shell layer is glass, and preferably silicate glass, borate glass, or phosphate glass. In the present invention, the thickness of the shell layer is preferably 0.2 to 10mm, more preferably 0.4 to 8mm, even more preferably 0.6 to 5mm, and even more preferably 1 to 3 mm. The invention preferably uses the glass as a shell layer, can meet the storage requirement of radioactive waste package, and the shell layer can ensure the requirement of structural strength within the thickness range, so that the leaching rate of the radioactive waste in the obtained radioactive waste-cladding solidified body is greatly lower than the national standard and even is zero.

The invention provides a preparation method of the radioactive waste-cladding solidified body in the technical scheme, which comprises the following steps:

coating a shell layer on the surface of the core body to obtain a radioactive waste-shell solidified body; the core body is made of radioactive wastes, and the shell layer is made of glass.

The invention first prepares the core. In the present invention, when the granulated waste (including the first granulated waste and/or the second granulated waste) satisfies the requirement of the particle size for core preparation, it can be used as it is; when the granular waste does not meet the requirement of the particle size for core preparation, such as the granular waste has a large particle size, the granular waste is preferably crushed in the present invention. The granular waste is preferably mixed with additives to form a core, and if the particle size of the granular waste is suitable for a subsequent coating method (such as a subsequent pre-coating method), the granular waste can be directly used without additional additives. In the present invention, the additive is preferably a ceramic preparation raw material or a glass preparation raw material, the ceramic preparation raw material preferably includes feldspar, quartz, clay, kaolin and lime, and the glass preparation raw material preferably includes quartz sand, soda ash, calcite, dolomite and borax; the additive amount and the content of each component of the additive are not specially limited, and the core body processing requirement can be met.

The preparation method of the core body is not particularly limited, and the core body meeting the requirements of shape, size, compactness and temperature resistance can be prepared by adopting a method and mature process equipment well known by the technical personnel in the field. The invention preferably mixes the radioactive waste with the additive, then carries out extrusion molding (aiming at larger-size materials) or spray granulation (aiming at smaller-size materials), and then carries out drying, sintering and solidification to obtain the core body meeting the requirements of shape, size and strength. The invention preferably obtains the core body which has uniform size, stable structure, firm adhesion and no radioactive waste shedding by the method; when the technology is improved and the coating strength of the outer glass shell layer meets the requirement, the size of the core body should be increased as much as possible so as to improve the treatment efficiency and reduce the operation cost.

After the core body is obtained, the surface of the core body is coated with the shell layer, and the radioactive waste-cladding solidified body is obtained. In the present invention, as a method for coating the shell layer on the surface of the core, any one of the following methods is preferably used, and the following methods will be specifically described.

Method one (slurry method): preparing raw materials for preparing the shell layer into slurry, coating the slurry on the surface of the core body, and then sequentially drying, sintering and cooling to obtain the radioactive waste-cladding solidified body.

The invention has no special limitation on the formula of the raw materials for preparing the shell layer and the slurry, and the formula is well known to those skilled in the art. The invention has no special limitation on the coating mode and the operation conditions of drying, sintering and cooling, can realize uniform coating of the slurry, and ensures that a complete and uniform glass shell layer is formed on the surface of the core body after subsequent drying, sintering and cooling treatment. In the invention, the slurry layer coated on the surface of the core body is melted in the sintering process, and then a glass shell layer is formed on the surface of the core body through cooling, so that the core body is wrapped.

Method two (glass frit process): melting the raw materials for preparing the shell layer, injecting the obtained molten material into a mold with a core body in the center, cooling, and demolding to obtain the radioactive waste-cladding solidified body.

In the present invention, the raw materials for preparing the shell layer are preferably the same as those in the above method, and thus, the description thereof is omitted.

The melting temperature is not specially limited, and the preparation raw materials of the shell layer are completely melted. In the present invention, the size of the mold is preferably determined according to the size of the radioactive waste-clad solidified body. In the invention, the molten material is cooled to form a glass shell layer on the surface of the core body, thereby realizing the wrapping of the core body.

Method three (pre-jacketing method): processing and prefabricating a preparation raw material of a shell layer to obtain a shell, wherein the shell is of a two-petal structure (shown in figure 2) or a cylindrical hollow structure (shown in figure 3) with one open end and one closed end; and placing the core body in the shell, and then sequentially sintering and cooling to obtain the radioactive waste-clad solidified body.

In the present invention, the raw materials for preparing the shell layer are preferably the same as those in the above method, and thus, the description thereof is omitted.

The method for preparing the shell is not particularly limited, and the method known to those skilled in the art can be adopted. The shell is preferably sintered by oxyhydrogen flame or a plasma torch, the shell outside the core is melted in the sintering process, the shell is bonded or closed under the action of surface tension (the two split shells are bonded together, and the opening of the cylindrical hollow shell is melted and closed), the core is closed in the shell, and then a glass shell layer is formed on the surface of the core through cooling, so that the core is wrapped. The operation conditions of sintering and cooling are not specially limited, and a complete and uniform glass shell layer is formed on the surface of the core body.

The invention preferably realizes the wrapping of the core body by the shell layer by any one of the three methods, and obtains the radioactive waste-cladding solidified body with uniform and complete shell layer, compact structure, round appearance (without edges and corners) and smooth outer wall.

The invention provides a preparation method of radioactive waste, which comprises the following steps:

placing the radioactive waste-cladding solidified body into a metal packaging barrel, pouring and fixing the radioactive waste-cladding solidified body by adopting cement mortar, and then covering and sealing the metal packaging barrel; wherein the radioactive waste-clad solidified body is the radioactive waste-clad solidified body in the technical scheme or the radioactive waste-clad solidified body prepared by the preparation method in the technical scheme.

The present invention preferably selects a specific preparation method according to the size of the radioactive waste-clad solidified body. When the radioactive waste-clad solidified body has a large size (50 to 160mm), the preparation method preferably comprises the following steps: placing the waste-cladding solidified body in a net frame made of inorganic materials with good heat conduction, wherein the distance between every two adjacent radioactive waste-cladding solidified bodies is 0.5-3 cm, placing the net frame containing the radioactive waste-cladding solidified body in a metal packaging barrel, and ensuring that the distances between the radioactive waste-cladding solidified body and the side wall, the bottom and the top of the metal packaging barrel are more than or equal to 2 cm; and then, adopting cement mortar to pour the radioactive waste-cladding solidified body, realizing filling balance and dense filling of the cement mortar through the integral vibration of the metal packaging barrel in the pouring process, and covering and sealing the metal packaging barrel after complete pouring for protecting the radioactive waste-cladding solidified body and facilitating subsequent disposal. When the radioactive waste-cladding solidified body is small in size (0.4 to 50mm), the preparation method preferably includes the steps of: adding 1/3 volume of cement mortar into the metal packaging barrel, immediately adding the radioactive waste-cladding solidified body, gradually adding the cement mortar, and simultaneously realizing filling balance and dense filling of the cement mortar through the integral vibration of the metal packaging barrel until the cement mortar is filled in the metal packaging barrel; and after the cement mortar is completely poured, covering and sealing the metal packaging barrel.

The invention adopts cement mortar to fix the radioactive waste-cladding solidified body, can realize secondary fixation and protection of the radioactive waste, and is convenient to ensure the safety requirement of the radioactive waste in the subsequent transportation, storage and disposal processes. The invention has no special requirements on the components and the proportion of the cement mortar, and the cement mortar which is well known by the technicians in the field can be adopted; the metal packaging barrel is not particularly limited, and is a disposal container commonly used in the art.

Fig. 4 is a flow chart of the preparation and preparation of the radioactive waste-cladding solidified body, specifically, the radioactive liquid waste and/or radioactive solid waste are used as raw materials to be treated, and are firstly treated into granular waste, processed into a core body, and then coated and solidified by glass to obtain the radioactive waste-cladding solidified body, and then the radioactive waste-cladding solidified body is barreled and fixed by cement, and then is subjected to subsequent treatment according to actual conditions.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.