CN107434388A - A kind of spent fuel dry-type storage container concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of spent fuel dry-type storage container concrete and preparation method thereof, described concrete includes binder materials, fine aggregate, coarse aggregate, water, composite fibre and water reducer；Preparation method includes, and described coarse aggregate, fine aggregate and composite fibre are carried out into the first stirring, obtain the first intermediate, described binder materials is added into the first described intermediate, and carries out the second stirring, obtains the second intermediate；Described water reducer and water are added into the second described intermediate, and carries out third time stirring, that is, obtains described spent fuel dry-type storage container concrete.Spent fuel dry-type storage container concrete provided by the invention, while there is very strong radiation hardness, high temperature resistant and fire resistance, meet requirement of the spent fuel dry-type storage container to its preparing raw material.

Description

Concrete for spent fuel dry storage container and preparation method thereof

technical field

The application relates to the field of nuclear power industry, in particular to a concrete used for a spent fuel dry storage container and a preparation method thereof.

Background technique

With the rapid development of the global nuclear power industry, the number of units under construction and in operation is gradually increasing, and the problem of comprehensive treatment of highly radioactive spent fuel discharged from the core has become increasingly prominent. According to IAEA statistics, global nuclear power plants have produced more than 350,000 tons of spent fuel so far, and it is estimated that by 2020, the global spent fuel amount will reach 445,000 tons. At present, the treatment methods of spent fuel are divided into wet storage and dry storage. The storage container for dry storage is a metal container or concrete container, the outside of which is provided with metal or concrete to provide radioactive shielding, and the inside uses natural or forced flow of gas to cool the spent fuel. The spent fuel dry storage and disposal method has the advantages of strong storage flexibility, simple operation management and monitoring, no secondary nuclear waste, low maintenance cost, strong operation and safety, and has been vigorously developed and used internationally.

Among the dry storage and disposal methods of spent fuel, the cost of concrete containers is the lowest. Due to the long-term synergistic effect of internal radiation and high temperature, external corrosive medium erosion and environmental effects on the concrete used for dry storage of spent fuel, it is a huge challenge to the long-term stability of the comprehensive performance of concrete within the design life. At present, the comprehensive performance of concrete for dry storage of spent fuel on the market still needs to be improved. It has very significant practical significance, economic benefits and social benefits.

Contents of the invention

This application solves the problem of low comprehensive performance of concrete for spent fuel dry storage containers in the prior art by providing a concrete for spent fuel dry storage containers and its preparation method. The spent fuel dry storage container provided by this application Concrete is not only resistant to high radiation, long-term high temperature and external corrosion, but also can maintain its own stable mechanical properties.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions.

According to the concrete for spent fuel dry storage container proposed by the present invention, the concrete includes cementitious material, fine aggregate, coarse aggregate, water, composite fiber and water reducing agent; wherein, the cementitious material is Cement, or a mixture of cement and active powder; the ratio of the components of the concrete used for the spent fuel dry storage container is: cement 150-360kg/m ³ , active powder 0-330kg/m ³ , fine Aggregate 450-640kg/m ³ , coarse aggregate 832-1024kg/m ³ , water 66-150kg/m ³ , volumetric dosage of composite fiber is 0.3%-2.5% of the total volume of concrete, water reducer The mass dosage is 1.5%-2.5% of the total mass of the concrete.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

Preferably, in the aforementioned concrete for spent fuel dry storage containers, the said permanent powder is one or more of silica fume, slag powder or fly ash.

Preferably, the aforementioned concrete for spent fuel dry storage containers, wherein the cement is one or more of P.I. type, P.II. type or P.S. type cement, and the strength level of the cement is not low 42.5.

Preferably, in the aforementioned concrete for spent fuel dry storage containers, the fine aggregate is ordinary river sand, and the fineness modulus of the fine aggregate is 2.60-3.20.

Preferably, the aforementioned concrete for spent fuel dry storage containers, wherein the coarse aggregate is one or more of granite, limestone, basalt or boron-containing gravel, the coarse aggregate The particle gradation is 5-10mm and 10-20mm gradation, and the maximum particle size does not exceed 20mm.

Preferably, the aforementioned concrete for spent fuel dry storage containers, wherein the composite fibers are a mixture of steel fibers and polypropylene fibers; wherein, the volume content of the steel fibers is the total amount of the concrete 0.2-2.0% of the volume, the volume dosage of the polypropylene fiber is 0.1-0.5% of the total volume of the concrete; the length of the steel fiber is 12-14mm, and the tensile strength is ≥2850MPa; the The length of the polypropylene fiber is 6-19mm, and the breaking strength is ≥688MPa.

Preferably, the aforementioned concrete for spent fuel dry storage containers, wherein the water-reducing agent is a liquid polycarboxylate-based water-reducing agent, and the water-reducing rate of the water-reducing agent is not less than 30%.

Preferably, the aforementioned concrete for spent fuel dry storage containers, wherein the concrete is irradiated with neutrons of 1*10 ¹⁵ n and gamma rays of 2.4*10 ⁷ Gy, the strength decreases by <10%. After a fire at 800°C, the strength will be reduced by <10%, the thermal conductivity will not be lower than 1.82W/(m·°C), the concrete density will be greater than 2350kg/m ³ , and the compressive strength will be not less than 30MPa.

The purpose of the present invention and the solution to its technical problems are also achieved by the following technical solutions.

According to a preparation method of concrete for spent fuel dry storage containers proposed by the present invention, according to any one of the aforementioned concretes, the preparation method includes the following steps: mixing the coarse aggregate, fine aggregate and performing the first stirring on the composite fiber to obtain the first intermediate; adding the gelling material to the first intermediate and performing the second stirring to obtain the second intermediate; adding the second intermediate to the Add the water reducer and water into the mixture, and carry out the third stirring to obtain the concrete for the spent fuel dry storage container.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

Preferably, the aforementioned method for preparing concrete for spent fuel dry storage containers, wherein the first stirring, the second stirring or the third stirring is carried out in a forced mixer, and the first stirring or the The stirring time of the second stirring is 30-60s, and the stirring time of the third stirring is 50-180s.

By means of the above-mentioned technical solution, the concrete for spent fuel dry storage container and its preparation method in the present invention have at least the following advantages:

1. The concrete used for the spent fuel dry storage container provided by the present invention has strong radiation resistance.

Spent fuel, also known as irradiated nuclear fuel, is nuclear fuel that has been exposed to radiation and used. Spent nuclear fuel contains large amounts of radioactive elements and is therefore radioactive, which, if not properly disposed of, can seriously affect the environment and the health of those who come into contact with them. Therefore, containers used to store spent fuel need to have strong radiation resistance in order to protect the environment and human beings from the harm of spent fuel.

In the prior art, although the preparation method of concrete with radiation resistance performance is recorded, due to the different application environments, radiation sources and radiation intensities, the existing radiation-resistant concrete cannot be directly applied to the spent fuel drying described in the present invention. Preparation of storage containers. The strength reduction of the concrete provided by the invention is less than 10% after being irradiated by neutron 1*10 ¹⁵ n and gamma ray 2.4*10 ⁷ Gy. It can be seen that the concrete provided by the present invention has strong radiation resistance, and can be used as a raw material for preparing spent fuel dry storage containers, and the spent fuel dry storage containers prepared by the present invention have high safety and meet the requirements for Requirements for the safety of spent fuel dry storage containers.

2. The concrete for spent fuel dry storage containers provided by the present invention has strong high temperature resistance and fire resistance.

The application environment of the spent fuel dry storage container is relatively special. During the application process, it has been exposed to internal high temperature environment and fire conditions under extreme conditions for a long time, which requires the selection of special gelling and reinforcing materials for the spent fuel dry storage container. To improve the stability of concrete hydration structure under high temperature or even fire conditions.

The concrete used for the spent fuel dry storage container provided by the present invention has strong high temperature resistance and fire resistance performance. Its high temperature resistance performance can be maintained at 300°C for 40 hours; The decrease in strength is less than 10%. It can be seen that the concrete provided by the invention has strong high temperature resistance and fire resistance, and can be used as a raw material for preparing spent fuel dry storage containers.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention will be described in detail below.

detailed description

The present invention will be described in further detail below in conjunction with specific examples, but not as a limitation of the present invention.

In order to further explain the technical means and effects adopted by the present invention to achieve the intended purpose of the invention, the concrete implementation of a concrete used for a spent fuel dry storage container proposed according to the present invention and its preparation method will be described below in conjunction with preferred embodiments. Mode, structure, feature and effect thereof are as follows in detail. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, the particular features, structures or characteristics of one or more embodiments may be combined in any suitable manner.

The invention provides a concrete used for a spent fuel dry storage container.

Concrete used as a storage container for spent fuel needs to satisfy strong radiation resistance, high temperature resistance and fire resistance at the same time. In the prior art, although the concrete with radiation or high temperature resistance is also recorded, the particularity of the application environment of the concrete provided by the present invention has different radiation sources and radiation intensities. Therefore, the existing concrete cannot be directly Applied to the preparation of spent fuel dry storage containers.

The concrete provided by the invention has strong radiation resistance, high temperature resistance and fire resistance, meets the safety requirements for preparing spent fuel dry storage containers, and is suitable for the preparation of spent fuel dry storage containers.

Further, in the concrete for spent fuel dry storage containers provided by the present invention, the active powder is one or more of silica fume, slag powder or fly ash; the cement is P.I. type, P.II type One or more of . or P.S. type cements with a strength class not lower than 42.5.

The active powder of the present invention, together with cement, is used as the cementitious material of concrete. The particles of active powder materials are small, which can fill the voids of cement and react with the hydration products of cement to make the concrete denser.

The hydration products of cement are an important source of concrete strength and an important barrier against various erosions. Cement, for example, improves concrete's ability to retain properties at high temperatures. But not all cements can meet the requirements of the present invention for high temperature resistance and fire resistance. The hydration products of P.I, P.II or P.S. cement selected in the present invention and the formed compact hydration structure can resist and shield the invasion of corrosive media and radioactive media.

Cement composition improves the performance retention of concrete in high temperature and aggressive environments. The invention further limits the types of cement and active powder, which is beneficial to improve the gelling effect on concrete and further improve the strength of concrete.

Further, in the concrete for spent fuel dry storage container provided by the present invention, the fine aggregate is ordinary river sand, and the fineness modulus of the fine aggregate is 2.60-3.20. The coarse aggregate is one or more of granite, limestone, basalt or boron-containing crushed stone, and the particle gradation of the coarse aggregate is 5-10mm and 10-20mm, and the largest particle The diameter does not exceed 20mm.

Compared with fine aggregate, coarse aggregate has larger particles and is the skeleton of concrete structure. Therefore, coarse aggregate can also be called aggregate. In low- and medium-strength concrete, the interface between coarse aggregate and cement paste is the weak zone, while in high-strength concrete, the coarse aggregate tends to be the first to fail.

The concrete of the present invention belongs to high-strength concrete, therefore, a reasonable coarse aggregate system must be selected and designed. The coarse aggregate selected in the present invention is one or more of granite, limestone, basalt or boron-containing gravel, which meets the strength requirements of spent fuel dry storage containers. Preferably, the coarse aggregate It is boron-type crushed stone, or the above-mentioned composition containing boron-type crushed stone, and the boron-containing stone can improve the radiation resistance of concrete.

Further, in the concrete for spent fuel dry storage container provided by the present invention, the composite fiber is a mixture of steel fiber and polypropylene fiber; wherein, the volume content of the steel fiber is the total volume of the concrete 0.2-2.0%, the volume dosage of the polypropylene fiber is 0.1-0.5% of the total volume of the concrete; the length of the steel fiber is 12-14mm, and the tensile strength is ≥2850MPa; the polypropylene fiber The length of the propylene fiber is 6-19mm, and the breaking strength is ≥688MPa.

Fiber can enhance the crack resistance of concrete, reduce the cracks caused by cement shrinkage, and the channel for gas transmission under high temperature and fire conditions, thereby improving the high temperature resistance of concrete. Preferably, the steel fiber can improve the strength, toughness and impact resistance of the concrete, and avoid nuclear waste leakage in the dry storage container of spent fuel in an accident; the burst resistance of the concrete under the polypropylene fiber can improve high temperature or fire conditions. The composition of steel fiber and polypropylene can comprehensively realize the toughness, burst resistance and impact resistance of concrete under the high temperature and irradiation conditions of spent fuel storage.

Example 1

This embodiment provides a composition and preparation method of concrete for a spent fuel dry storage container.

The composition of the concrete used for the spent fuel dry storage container provided in this example is shown in Table 1.

The preparation method of the concrete for the spent fuel dry storage container provided in this example is as follows: the coarse aggregate, fine aggregate and composite fiber used in this example are first stirred in a forced mixer, and the stirring time is 60s to obtain The first intermediate; add the gelling material used in the present embodiment to the first intermediate, and carry out the second stirring in the forced mixer, and the stirring time is 60s to obtain the second intermediate; add the second intermediate to the first intermediate The water reducer and water used in this example were added to the second intermediate, and the third stirring was carried out in a forced mixer for 180 s to obtain the concrete for spent fuel dry storage container described in this example.

The physical properties of the concrete prepared in this example are shown in Table 2.

Example 2

This embodiment provides a composition and preparation method of concrete for a spent fuel dry storage container.

The composition of the concrete used for the spent fuel dry storage container provided in this example is shown in Table 1.

The preparation method of the concrete for the spent fuel dry storage container provided in this example is the same as that in Example 1 or with appropriate adjustments.

The physical properties of the concrete prepared in this example are shown in Table 2.

Example 3

This embodiment provides a composition and preparation method of concrete for a spent fuel dry storage container.

The composition of the concrete used for the spent fuel dry storage container provided in this example is shown in Table 1.

The preparation method of the concrete for the spent fuel dry storage container provided in this example is the same as that in Example 1 or with appropriate adjustments.

The physical properties of the concrete prepared in this example are shown in Table 2.

Example 4

This embodiment provides a composition and preparation method of concrete for a spent fuel dry storage container.

The composition of the concrete used for the spent fuel dry storage container provided in this example is shown in Table 1.

The preparation method of the concrete for the spent fuel dry storage container provided in this example is the same as that in Example 1 or with appropriate adjustments.

The physical properties of the concrete prepared in this example are shown in Table 2.

Table 1. Components of concrete used in spent fuel dry storage containers provided in Examples 1-4

The physical property of the concrete that table 2 embodiment 1-4 prepares

It can be seen from the data in Table 2 that the concrete for spent fuel dry storage containers prepared by the present invention has strong radiation resistance, high temperature resistance and fire resistance, and meets the performance requirements of spent fuel dry storage containers for concrete.

In the foregoing embodiments, the descriptions of each embodiment have their own emphases, and for parts not described in detail in a certain embodiment, reference may be made to relevant descriptions of other embodiments. It should be noted that Examples 1-4 are only practical cases of the present invention. Although other components and their contents provided by the present invention are not shown in the examples, the invention of the present invention can also be realized.

It can be understood that related features in the above devices can refer to each other. In addition, "first", "second" and so on in the above embodiments are used to distinguish each embodiment, and do not represent the advantages and disadvantages of each embodiment.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, in order to streamline this disclosure and to facilitate an understanding of one or more of the various inventive aspects, various features of the invention are sometimes grouped together in a single embodiment, or in its description. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

Those skilled in the art can understand that the components in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment. The components in the embodiments may be combined into one component, and furthermore may be divided into a plurality of subcomponents. All features disclosed in this specification (including accompanying claims, abstract) and all parts of any apparatus so disclosed may be combined in any combination, unless at least some of such features are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including accompanying claims, abstract) may be replaced by alternative features serving the same, equivalent or similar purpose.

Furthermore, those skilled in the art will understand that although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention. and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination. The various component embodiments of the present invention can be implemented in hardware, or in a combination thereof.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of parts or components not listed in a claim. The word "a" or "an" preceding an element or component does not exclude the presence of a plurality of such elements or components. The invention can be implemented by means of an apparatus comprising several different components. In a claim enumerating several components, several of these components may be embodied by the same component item. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names.

The numerical range stated in the present invention includes all the numerical values in this range, and includes the range value composed of any two numerical values in this range. For example, "the volume content of the composite fiber is 0.3%-2.5% of the total volume of the concrete", this numerical range includes all numerical values between 0.3%-2.5%, and includes any two numerical values within this range (for example : 0.5%, 1.0%) constitutes the range value (0.5%-1.0%); the different numerical values of the same index appearing in all embodiments of the present invention can be combined arbitrarily to form the range value.

The technical features in the claims of the present invention and/or the description can be combined, and the combination is not limited to the combination obtained by reference in the claims. The technical solution obtained by combining the technical features in the claims and/or the description is also within the protection scope of the present invention.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to this invention. within the scope of the technical solution of the invention.

Claims (10)

1. A concrete for a spent fuel dry storage container, characterized in that, The concrete includes cementitious material, fine aggregate, coarse aggregate, water, composite fiber and water reducing agent; wherein, the cementitious material is cement, or a mixture of cement and active powder; The ratio of each component of the concrete for spent fuel dry storage container is: cement 150-360kg/m ³ , active powder 0-330kg/m ³ , fine aggregate 450-640kg/m ³ , coarse aggregate 832-1024kg/m ³ of material, 66-150kg/m ³ of water, the volume dosage of composite fiber is 0.3%-2.5% of the total concrete volume, and the mass dosage of water reducer is the total concrete mass 1.5%-2.5%. 2. The concrete for spent fuel dry storage container according to claim 1, characterized in that: The active powder is one or more of silica fume, slag powder or fly ash. 3. The concrete for spent fuel dry storage container according to claim 1, characterized in that, The cement is one or more of P.I. type, P.II. type or P.S. type cement, and the strength grade of the cement is not lower than 42.5. 4. The concrete for spent fuel dry storage container according to claim 1, characterized in that: The fine aggregate is common river sand, and the fineness modulus of the fine aggregate is 2.60-3.20. 5. The concrete for spent fuel dry storage container according to claim 1, characterized in that: The coarse aggregate is one or more of granite, limestone, basalt or boron-containing crushed stone, and the particle gradation of the coarse aggregate is 5-10mm and 10-20mm, and the largest particle The diameter does not exceed 20mm. 6. The concrete for spent fuel dry storage container according to claim 1, characterized in that, The composite fiber is a mixture of steel fiber and polypropylene fiber; wherein, the volume dosage of the steel fiber is 0.2% to 2.0% of the total volume of the concrete, and the volume dosage of the polypropylene fiber is 0.1-0.5% of the total volume of the concrete; The length of the steel fiber is 12-14mm, and the tensile strength is ≥ 2850MPa; the length of the polypropylene fiber is 6-19mm, and the breaking strength is ≥ 688MPa. 7. The concrete for spent fuel dry storage container according to claim 1, characterized in that: The water reducer is a liquid polycarboxylate water reducer, and the water reducer has a water reducing rate of not less than 30%. 8. The concrete for spent fuel dry storage container according to claim 1, characterized in that: After the concrete is irradiated with neutrons of 1*10 ¹⁵ n and gamma rays of 2.4*10 ⁷ Gy, the strength decreases by <10%, and after a fire at 800°C, the strength decreases by <10%, and the thermal conductivity is not lower than 1.82W /(m·℃), the concrete density is greater than 2350kg/m ³ , and the compressive strength is not less than 30MPa. 9. A preparation method of concrete for spent fuel dry storage containers, characterized in that, The concrete for spent fuel dry storage container according to any one of claims 1-8, the preparation method thereof comprises the following steps: performing the first stirring on the coarse aggregate, fine aggregate and composite fiber to obtain the first intermediate; adding the gelling material to the first intermediate, and performing a second stirring to obtain a second intermediate; Add the water reducer and water into the second intermediate, and carry out the third stirring to obtain the concrete for the spent fuel dry storage container. 10. A method for preparing concrete for spent fuel dry storage containers according to claim 9, characterized in that: The first stirring, the second stirring or the third stirring are carried out in a forced mixer, The stirring time of the first stirring or the second stirring is 30-60s, and the stirring time of the third stirring is 50-180s.