JP3821889B2 - Disposal method for contaminated concrete waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating and disposing of contaminated concrete waste generated during dismantling of a nuclear power plant, a nuclear facility such as a fuel reprocessing plant of the nuclear power plant, and a facility for handling hazardous substances.
[0002]
[Prior art]
Conventionally, as a method for treating and treating this type of concrete waste, there is one shown in FIG. As shown in FIG. 5, when the nuclear power plant 101 and the reprocessing facility 102 are dismantled, contaminated waste 103 contaminated with radioactivity is generated. This contaminated waste 103 includes contaminated concrete waste 105 contaminated by radioactivity and other waste 104 including steel frames.
[0003]
The contaminated concrete waste 105 is crushed to the extent of a human head, mixed with the filling mortar 108 supplied from the raw plant 107, and filled into the drum can 110. The drum can 110 is placed in a concrete pit, buried in soil, and finally stored.
[0004]
[Problems to be solved by the invention]
However, in the conventional disposal method described above, when the concrete pits and the shields of the drum cans 110 are damaged and the pollutants come into direct contact with the groundwater, the pollutants elute into the groundwater and flow into the ground in a relatively short period of time. Therefore, there is a problem that the contaminated area expands until the concrete pit or the drum can is repaired and the pollutant is reshielded.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for treating and treating contaminated concrete waste that can suppress the spread of contamination when a shield is damaged.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the method for treating and disposing of contaminated concrete waste according to the first aspect of the present invention comprises crushing contaminated concrete waste to form granular concrete waste having a continuous particle size distribution in which hydraulic substances are present. The granular concrete waste is first separated into a coarse part composed of grains having a particle size of more than 5 mm and not more than 40 mm and a fine particle part comprising particles having a particle size of more than 0.15 mm and not more than 5 mm. And the process of
A second step of heating and pulverizing a part of the fine particles to produce fine particles containing unhydrated hydraulic material having a brain value of 1000 to 5000 cm ² / g;
And a third step of mixing the coarse, fine, and fine particles as the granular concrete waste, mixing the mixture, agitating and filling the container, and storing it in an underground storage. .
[0007]
According to the first aspect of the present invention, when groundwater or the like enters the contamination processing container filled with the granular concrete waste during long-term storage, the groundwater reacts with the hydraulic substance. Used to solidify the granular concrete waste. Accordingly, it is possible to suppress the elution of pollutants due to groundwater intrusion.
[0008]
Moreover, since the granular concrete waste has a continuous particle size distribution, the fine particles having a relatively small particle size can be used as a solidified material, and the coarse particles having a relatively large particle size can be used as a coarse aggregate. The fine particles having a medium particle size can be used as the fine aggregate. Further, a hydraulic substance remaining on the surface of the coarse and fine particles can also be used as the solidifying material. Therefore, the amount of waste after the treatment can be greatly reduced without supplying the solidification material from the outside as in the conventional example and without having a low filling rate of the aggregate.
[0009]
In addition, since the granular concrete waste having a continuous particle size distribution is used, fine particles enter between coarse particles and the filling property is improved, so that the amount of waste after treatment can be greatly reduced.
[0010]
Further, the invention of claim 3 is the method for treating and disposing of contaminated concrete waste according to claim 1 or 2 , wherein in the third step, the weight is 5.0% with respect to the total weight of the contaminated concrete waste. % Or less of water is added to the granular concrete waste.
[0011]
According to the third aspect of the present invention, the amount of water added to the concrete waste is set to a minimum amount necessary for compacting the granular concrete waste, and is small enough not to generate excess water.
The compaction effect due to water and vibration works, and the mixture is packed more densely in the contamination treatment container, so the amount of waste can be reduced, and the coarse and fine particles are dry inside, and the surface Some dry parts remain. Therefore, when the mixture is stored in the storage, when the groundwater enters the storage, the intruded water is gradually absorbed by the drying unit, and further the unhydrated hydraulic substance remaining in the drying unit. Contamination is delayed due to consumption of solidification.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0013]
In FIG. 1, the process of embodiment of the disposal method of the contaminated concrete waste of this invention is shown. This embodiment is a method of treating contaminated waste contaminated with radioactivity generated when a nuclear power plant is dismantled.
[0014]
First, this contaminated waste is separated into concrete waste 2 and other waste such as steel frames.
[0015]
Next, after crushing the concrete waste 2 with a crusher 5, a coarse particle portion 7 having a particle size exceeding 5 mm and having a particle size of 40 mm or less, and a fine particle having a particle size exceeding 0.15 mm and a particle having a particle size of 5 mm or less. Sort into minutes 6. Then, the fine particle portion 6 is separated into 6A which is introduced into the heating pulverizer 8 and made into the fine particle portion 10 and 6B which is packed in the drum can 13 as it is as a fine particle portion.
[0016]
In this embodiment, with respect to the total weight 100 of the concrete waste 2, the weight percentage of the coarse grain 7 is 50%, the weight percentage of the fine grain 6B is 30%, The weight percentage of 6A made into the grain fraction 10 was 20%. The particle size distribution of the mixture of coarse particles 7 after grinding and 6B made into fine particles and 6A made into fine particles 10 is shown by a broken line K1 connected by a solid line in FIG. The broken line K1 indicates a value obtained by sequentially adding the weight% of each particle size in order from the smaller particle size to the larger particle size. In FIG. 2, the region between the two dotted lines K2 and K3 indicates the range of the particle size distribution that can minimize the gap between the grains of the mixture and increase the compaction density.
[0017]
Next, the portion 6A of the fine particle portion 6 which is made into the fine particle portion 10 is heated by the heat pulverizer 8 and finely pulverized to a brain value (fineness) of 1000 to 5000 cm ² / g.
[0018]
On the other hand, the coarse particle portion 7 having a particle size exceeding 5 mm is subdivided and shaped as a coarse aggregate.
[0019]
Next, the coarse particle portion 7, the fine particle portion 6B, and the fine particle portion 6A are packed in the drum can 13 and mixed with stirring or mixed and stirred, and then shaken and compacted by vibration.
[0020]
In this embodiment, the coarse particle portion 7, the fine particle portion 6B, and the fine particle portion 6A are mixed and stirred after being packed in the drum can 13, but after mixing and stirring, the drum portion 13 is packed and shaken. Further, compaction by vibration may be performed. For this mixing, an ordinary mixer such as a puggle mixer, a mortar mixer, or a pan mixer may be used.
[0021]
Next, after the drum cans 13 are arranged in the concrete pits 15, the concrete is poured and hardened. And the earth and sand 17 are piled up on the concrete, and it will be in a final storage state.
[0022]
Here, the mixing | blending content of the mixture of the said coarse particle part 7, the fine particle part 6B, and the fine particle part 10 is shown to the mixing examples 1-0 and 2-0 of FIG. As shown in columns 1-0 and 2-0, the mixture has a solidified material having the fine particle content of 10. Further, the volume percentage (fine aggregate ratio) of the fine particle portion 6B with respect to (coarse particle portion + fine particle portion) was 40% in the blending example 1-0 and 31% in the blending example 2-0.
[0023]
According to this embodiment, during long-term storage, when groundwater or the like has entered the drum can 13 as a contamination treatment container filled with the mixture of the coarse particles 7, the fine particles 6B, and the fine particles 10. In addition, this groundwater is consumed for hydrating and hardening the unhydrated hydraulic substance in the fine particle fraction 10 to solidify the mixture. Therefore, the elution of the pollutant due to the groundwater intrusion can be delayed by this consumption, and the elution of the pollutant into the groundwater can be suppressed.
[0024]
In addition, the granular concrete waste composed of the coarse portion 7, fine portion 6B, and fine portion 10 has a continuous particle size distribution as shown by the broken line K1 in FIG. The fine particle portion 10 can be used as a solidified material, the coarse particle portion 7 having a large particle size can be used as a coarse aggregate, and the fine particle portion 6B having a medium particle size can be used as a fine aggregate. Therefore, the amount of waste after the treatment can be greatly reduced without supplying the solidification material from the outside as in the conventional example and without having a low filling rate of the aggregate.
[0025]
In addition, since the granular concrete waste having a continuous particle size distribution is used, fine particles enter between coarse particles and the filling property is improved, so that the amount of waste after treatment can be greatly reduced.
[0026]
Moreover, according to this embodiment, the particle size distribution of the granular concrete waste composed of the above-mentioned coarse portion 7, fine portion 6B, and fine portion 10 is set within a range sandwiched by dotted lines K2, K3 shown in FIG. Therefore, the granular concrete waste can be filled most densely into the drum can 13 by minimizing the gap between the grains. Therefore, the final amount of waste can be reduced.
[0027]
In addition, as a second embodiment, a predetermined amount of water is added to the coarse particle portion 7, the fine particle portion 6B, and the fine particle portion 6A, mixed and stirred, and the mixture is packed in the drum can 13 and vibrated. You may make it perform the compaction by vibration. In this case, the effect of compaction with water acts and the filling can be performed more densely.
[0028]
In addition, this embodiment is necessary for compacting the granular concrete waste composed of the above-mentioned coarse fraction 7, fine fraction 6B and fine fraction 10 with the amount of water added to the fine fraction 10 of the concrete waste 2. The minimum amount (specifically, 5.0% by weight with respect to the total weight of the concrete waste 2) was set to such a small amount that no excess water was generated.
[0029]
This embodiment can reduce the amount of waste because the compaction effect by water and vibration works and the mixture is tightly filled with the drum can. In addition, the coarse particles and the fine particles are in a dry state, and a dry portion remains on a part of the surface. Therefore, when the mixture is stored in the storage, when the groundwater enters the storage, the intruded water is gradually absorbed by the drying unit, and further the unhydrated hydraulic substance remaining in the drying unit. Contamination is delayed due to consumption of solidification.
[0030]
In addition, since most of the radioactive substances are generally adsorbed by alkaline mortar, according to this embodiment, the effect of suppressing the elution of radioactive substances from the waste 2 is high.
[0031]
In addition, in the said embodiment, as shown to 1-1 column of FIG. 3, although the fine particle part 10 was used as the solidification material, as shown to 1-2 column of FIG. Recycled cement added with blast furnace slag powder may be used as a solidifying material. Moreover, in the said embodiment, although the particle size distribution shown by the broken line K1 of FIG. 2 was employ | adopted, you may employ | adopt the particle size distribution shown by the broken line K4 of FIG. In this case, the blending content is the blending content shown in the columns 2-1 or 2-2 of FIG. 3, and is fine aggregate compared to the blending examples shown in the columns 1-1 and 1-2. The rate was reduced by 9% and the water / recycled cement ratio was reduced by 3.2%.
[0032]
[Experimental example]
Here, the consistency, compressive strength (kgf / m ² ) and filling rate, which are indicators of “hardness to flow”, are measured for each of the above blending examples 1-1, 1-2, 2-1 and 2-2. The results are shown in FIG. The consistency is expressed as a modified VC value. This corrected VC value is the time from compacting the concrete as a test object using a shaking table (frequency: 3000 rpm, amplitude: 1 mm) and an overweight (20 kg) (JST) Standard specification [1996 version], RCD concrete consistency test method (draft) (JSCE-F507-1995)). The compressive strength (kgf / m ² ) is a breaking pressure when a compressive force is applied to a sample that has passed a predetermined number of days after the concrete of the sample is kneaded. In addition, the filling rate is expressed as a percentage of the volume of the sample after applying pressure to this sample to separate and remove bubbles when the concrete container of the kneaded sample is filled in a predetermined container. It is the expressed value.
[0033]
As can be seen from FIG. 4, for compressive strength, the example in which the solidified material is recycled cement (Formulation Example 1-2, Formulation Example 2-2) is the example in which the solidified material is a fine particle (Formation Example). Compared to 1-1, Formulation Example 2-1), the value was about 8 times (28th day), indicating a significantly higher strength. On the other hand, with regard to the corrected VC value indicating the consistency, which is an index of “hardness to flow”, the blending examples 1-1 and 2-1 using the fine particles as the solidifying material are the blending examples 1 using the recycled cement as the solidifying material. The values were -2 and 2-2 twice and 1.7 times.
[0034]
In addition, in the blending examples 2-1 and 2-2 in which the fine aggregate ratio (volume%) is decreased by 9% compared to the blending examples 1-1 and 1-2, the filling rate is decreased by 3% and the compression is reduced. The strength (28th day) decreased by 30% to 40%, and the corrected VC value indicating “hardness of flow” increased by 10 seconds.
[0035]
In addition, in the said embodiment, although 5.0 weight% of water was added with respect to the total weight of a contaminated concrete waste, you may add 5.0 weight% or less of water. Further, as shown in formulation examples 1-0 and 2-0 in FIG. 3, it is not necessary to add water.
[0036]
Moreover, although the said embodiment demonstrated the method to process the concrete waste 2 contaminated with the radioactivity, the application of this invention is not restricted to the radioactive concrete waste 2, but is contaminated with harmful substances, such as a chemical. It can also be applied to the treatment of waste concrete. Moreover, in the said embodiment, although the drum can 13 was used as a container, of course, a container is not restricted to the drum can 13, The metal container of a form different from a drum can may be sufficient, and it is made of resin or glass. It may be a container.
[0037]
In addition, when solidifying fine particles in a contamination treatment container, water reducing agents such as lignin sulfonic acids, polyols and oxycarboxylates, and high performance water reducing agents such as alkylallyl sulfonates and sulfonated melamine condensates are used. Can be used.
[0038]
【The invention's effect】
As apparent from the above, the method for treating and treating contaminated concrete waste according to the present invention crushes the contaminated concrete waste into granular concrete waste having a continuous particle size distribution in which hydraulic substances are present. A first step of separating the granular concrete waste into a coarse portion composed of particles having a particle size exceeding 5 mm and not exceeding 40 mm and a fine particle portion including particles having a particle size exceeding 0.15 mm and not exceeding 5 mm; A second step of heating and pulverizing part of the fine particles to produce fine particles containing unhydrated hydraulic material having a brain value of 1000 to 5000 cm ² / g, and the granular concrete And a third step of mixing coarse particles, fine particles, and fine particles as waste, stirring them, filling them into a contaminated container, and storing them in an underground storage.
[0039]
According to the first aspect of the present invention, when groundwater or the like enters the contamination processing container filled with the granular concrete waste during long-term storage, the groundwater reacts with the hydraulic substance. Used to solidify the granular concrete waste. Accordingly, it is possible to suppress the elution of pollutants due to groundwater intrusion.
[0040]
Since the granular concrete waste has a continuous particle size distribution, fine particles with relatively small particle size can be used as a solidified material, and coarse particles with relatively large particle size can be used as coarse aggregate. The fine particles having a medium particle size can be used as the fine aggregate. Therefore, the amount of waste after the treatment can be greatly reduced without supplying the solidification material from the outside as in the conventional example and without having a low filling rate of the aggregate.
[0041]
In addition, since the granular concrete waste having a continuous particle size distribution is used, fine particles enter between coarse particles and the filling property is improved, so that the amount of waste after treatment can be greatly reduced.
[0042]
Further, the invention of claim 3 is the method for treating and disposing of contaminated concrete waste according to claim 1 or 2 , wherein in the third step, the weight is 5.0% with respect to the total weight of the contaminated concrete waste. % Water is added to the granular concrete waste.
[0043]
According to the third aspect of the present invention, the amount of water added to the concrete waste is set to a minimum amount necessary for compacting the granular concrete waste, and is small enough not to generate excess water.
The compaction effect due to water and vibration works, and the mixture is packed more densely in the contamination treatment container, so the amount of waste can be reduced, and the coarse and fine particles are dry inside, and the surface Some dry parts remain. Therefore, when the mixture is stored in the storage, when the groundwater enters the storage, the intruded water is gradually absorbed by the drying unit, and further the unhydrated hydraulic substance remaining in the drying unit. Contamination is delayed due to consumption of solidification.
[Brief description of the drawings]
FIG. 1 is a diagram showing processing steps of an embodiment of a processing and disposal method for contaminated concrete waste according to the present invention.
FIG. 2 is a characteristic diagram showing a particle size distribution of the concrete waste crushed in the embodiment.
FIG. 3 is a chart showing an example of mixing concrete waste crushed in the embodiment.
FIG. 4 is a chart showing the result of a characteristic test for each of the above blending examples.
FIG. 5 is a diagram showing processing steps of a conventional contaminated concrete waste processing and disposal method.
[Explanation of symbols]
2 ... concrete waste, 5 ... crusher, 6 ... fine fraction,
6A: Minute portion, 6B: Fine portion, 7: Coarse portion,
8 ... Heat crusher, 10 ... Fine particles, 13 ... Drum,
15 ... Concrete pit.

Claims (4)

The contaminated concrete waste is crushed into a granular concrete waste having a continuous particle size distribution in the presence of a hydraulic substance, and the granular concrete waste is coarsely composed of grains having a particle size of more than 5 mm and not more than 40 mm. A first step of separating into a granule and a fine granule having a grain size exceeding 0.15 mm and not more than 5 mm;
A second step of heating and pulverizing a part of the fine particles to produce fine particles containing unhydrated hydraulic material having a brain value of 1000 to 5000 cm ² / g;
A third step of mixing the coarse, fine and fine particles as the granular concrete waste, agitating and filling the contaminated container and storing it in an underground storage; Disposal method of contaminated concrete waste. In the disposal method of the contaminated concrete waste according to claim 1 ,
The third step is
A method for treating and treating contaminated concrete waste, characterized in that the concrete waste filled in the container is vibrated and compacted by vibration. In the disposal method of the contaminated concrete waste according to claim 1 or 2 ,
In the third step, a contaminated concrete waste disposal method, wherein 5.0% by weight or less of water is added to the granular concrete waste with respect to the total weight of the contaminated concrete waste. In the disposal method of the contaminated concrete waste according to any one of claims 1 to 3 ,
The third step is
A method for treating and treating contaminated concrete waste, characterized in that gypsum powder and blast furnace slag powder are added to the fine particles.

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