JP2014016301A - Method and system for decontaminating object contaminated by radioactive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for decontaminating an object contaminated by a radioactive material that can reduce the concentration of radioactive cesium to 100 Bq/kg or less, included in a decontamination object contaminated by a radioactive material.SOLUTION: A system for decontaminating an object contaminated by a radioactive material comprises: a washing liquid storing tank 2 for conditioning and storing a natural surfactant washing liquid: a washing machine 4 for performing cavitation jet washing using a natural surfactant as a washing liquid; a collection tank 6 for collecting the natural surfactant washing liquid and a decontamination object; a nano-bubble washing liquid storing tank 8 for conditioning and storing a carbonic acid nano-bubble washing liquid; a washing machine 9 for performing cavitation jet washing using a carbonic acid nano-bubble water as a washing liquid; a classification machine 14 for classifying the decontamination object and suspension water; a washing waste liquid storing tank 15 for collecting the suspension water; and a suspension water treating machine 16 for separating deposit from water to be treated by aggregating, adsorbing, and precipitating radioactive materials and fine particles in the suspension water by using an aggregating, adsorbing, and precipitating agent. The cavitation jet washing is performed by using the natural surfactant washing liquid, and then by using the carbonic acid nano-bubble washing liquid.

Description

  The present invention includes incombustible materials contaminated with radioactive materials (soils such as schoolyards, gardens and parks, sludge generated from water treatment plants, sea sand, tile scraps, etc.) and combustible materials (chip fallen trees, driftwood and Decontamination method and decontamination of decontaminated materials contaminated with radioactive materials that can be decontaminated to a concentration of 100 Bq / kg or less for thinned wood, fallen leaves, etc.) and reused as construction materials and fuel About the system.

  Japan Atomic Energy Agency (JAEA) commissions the government agency commissioned project “Decontamination Demonstration in Evacuation Zones, etc. Related to Fukushima Daiichi Nuclear Power Station Accident” for decontamination of soil contaminated with radioactive materials In 2011, the “Decontamination Technology Demonstration Test Project” was conducted. In 2011, Fukushima Prefecture conducted a “decontamination technology demonstration project field trial”. According to a report published on the JAEA website (Non-patent Document 1) and the website of Fukushima Prefecture, the mechanical decontamination methods include ball mill equipment, crushing equipment, and high-pressure jet equipment, and chemical decontamination methods. Applied oxalic acid dissolution, but none of the decontamination methods reduced the radioactive cesium concentration in the soil to 100 Bq / kg or less.

Japan Atomic Energy Agency website, “(3) Report on decontamination technology verification test results, 2011 decontamination technology verification test project”, March 26, 2012, [June 25, 2012 Day search], Internet URL: http://www.jaea.go.jp/fukushima/decon04/ke05.pdf

  According to Ministry of the Environment Notification No.76, the average concentration of radioactive cesium (total of Cs-134 and Cs-137) in products recycled from disaster waste caused by the Great East Japan Earthquake is 100 Bq / It is set as kg or less. If soil and thinned wood contaminated with radioactive cesium cannot be decontaminated to 100 Bq / kg or less, they cannot be reused as construction materials, and there is a problem that the amount of radioactive waste stored cannot be reduced or increased. .

Further, if the cleaning waste liquid after decontamination is purified and cannot be reused as cleaning water, the cleaning waste liquid becomes radioactive liquid waste, and there is a problem that the storage amount of the radioactive liquid waste increases. The radioactive cesium concentration in the cleaning waste liquid after decontamination needs to be purified below the standard value of the Ministry of the Environment shown below.
Cs-134 concentration (Bq / L) / 60 (Bq / L) + Cs-137 concentration (Bq / L) / 90 (Bq / L) ≦ 1

  Therefore, the present invention provides a decontamination method and a decontamination system for a decontaminated object contaminated with a radioactive substance that can be decontaminated to a radioactive cesium concentration of the decontaminated object contaminated with a radioactive substance to 100 Bq / kg or less. Is an issue.

  In addition, the present invention can decontaminate the radioactive cesium concentration of the decontaminated material contaminated with radioactive substances to 100 Bq / kg or less, and purify the radioactive cesium concentration of the cleaning waste liquid after decontamination to a standard value or less of the Ministry of the Environment. It is an object to provide a decontamination method and a decontamination system for an object to be decontaminated contaminated with a radioactive substance.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

(Claim 1)
In a decontamination method of a decontaminated object contaminated with a radioactive substance, a cavitation jet cleaning is performed using a natural surfactant cleaning liquid, followed by a cavitation jet cleaning using a carbonic acid nanobubble cleaning liquid. Decontamination method for contaminated objects to be decontaminated.

(Claim 2)
Natural surfactant cleaning liquid adjustment process, cavitation jet cleaning process using natural surfactant as cleaning liquid, carbonated nanobubble cleaning liquid adjustment process, cavitation jet cleaning process using carbonated nanobubble water, and decontaminated product And a step of classifying the suspension into water (including radioactive substances and fine particles), a step of aggregating and precipitating radioactive substances and fine particles in the suspension water with an agglomeration adsorbing precipitant, and separating the precipitate and the water to be treated; The method for decontamination of a decontaminated material contaminated with a radioactive substance according to claim 1, wherein the water to be treated is reused as cleaning water for decontamination.

(Claim 3)
3. The removal of a decontaminated material contaminated with a radioactive substance according to claim 1 or 2, wherein the natural surfactant concentration of the natural surfactant cleaning liquid is in the range of 0.01 to 0.1%. Dyeing method.

(Claim 4)
The carbonic acid nanobubble cleaning liquid is produced by supplying carbon dioxide gas to the nanobubble generator in a range of 2.5 to 100% with respect to the nanobubble water generation amount (L / min) of the nanobubble generator. The decontamination method of the to-be-decontaminated thing contaminated with the radioactive substance of Claim 1 or 2.

(Claim 5)
The high-pressure water for driving of 15 to 25 MPa is supplied to the cavitation jet cleaning process using the natural surfactant as a cleaning liquid and the cavitation jet cleaning process using the carbonated nanobubble water as a cleaning liquid. Or the decontamination method of the to-be-decontaminated material contaminated with the radioactive substance of 2.

(Claim 6)
3. The method for decontamination of a decontaminated material contaminated with a radioactive substance according to claim 2, wherein the coagulation adsorbing precipitant contains binos powder obtained by drying Parachlorella sp. Binos. .

(Claim 7)
The method for decontamination of a decontaminated object contaminated with a radioactive substance according to claim 2 or 6, wherein the agglomerated adsorbing precipitant is added in an amount of 0.1 to 0.5 g / L to the cleaning waste liquid after decontamination. .

(Claim 8)
In a decontamination system for decontaminated materials contaminated with radioactive substances, a cleaning liquid storage tank that adjusts and stores a natural surfactant cleaning liquid, a cleaning machine that uses a natural surfactant as a cleaning liquid and a cavitation jet cleaning, and a natural surfactant cleaning liquid A recovery tank for recovering the decontaminated material, a nanobubble cleaning liquid storage tank for adjusting and storing the carbonic acid nanobubble cleaning liquid, a washing machine for cavitation jet cleaning using the carbonic acid nanobubble water as a cleaning liquid, (Including particles), a washing waste liquid storage tank that collects suspended water, and agglomerated adsorptive precipitants that aggregate and adsorb the radioactive substances and fine particles in the suspended water to separate the precipitate and the water to be treated. A decontamination system for an object to be decontaminated by a radioactive material, comprising a suspension water treatment machine.

  The effects of the present invention are as follows.

(1) Decontaminated materials after decontamination (soil, chipped fallen trees, driftwood, thinned wood, etc.) have a radioactive cesium (Cs-134 + Cs-137 total) concentration of 100 Bq / kg or less. It can be reused for construction materials.

(2) Since 80% or more of the decontaminated soil of 100 Bq / kg or less can be recovered, the amount of disaster waste stored can be greatly reduced and reused.

(3) The cleaning waste liquid subjected to the purification treatment can be reused as cleaning water because the radioactive cesium concentration is not more than the detection lower limit value and the COD is not more than 20 mg / L.

(4) When the cleaned cleaning waste liquid is discharged, the radioactivity concentration is not more than the detection lower limit value and the COD is not more than 20 mg / L, so there is no influence on the environment.

Apparatus flow diagram for explaining a decontamination system according to the present invention Implementation procedure of soil decontamination according to the present invention Treatment procedure of washing waste liquid after soil decontamination according to the present invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the present invention, to-be-contaminated materials contaminated with radioactive substances are non-combustible materials such as schoolyards, gardens, parks, soil, sludge generated from water treatment plants, sea sand, waste tiles, etc. Examples include chipped fallen trees, driftwood, thinned wood, and fallen leaves.

(Equipment configuration)
FIG. 1 shows an apparatus configuration of a decontamination system for an object to be decontaminated contaminated with a radioactive substance.

  In the present embodiment, soil is used as a decontamination object contaminated with radioactive substances.

  Contaminated soil was decontaminated in two stages. In the first stage of decontamination, a supply tank 3 that receives a predetermined amount of soil 1 before decontamination and a cleaning liquid storage tank 2 that receives a natural surfactant cleaning liquid, and a soil 1 mixed with the natural surfactant cleaning liquid are cleaned. Passed through a first stage cavitation jet washer 4, a first stage plunger pump 5 for supplying driving high-pressure water connected to the first stage cavitation jet washer 4, and a first stage cavitation jet washer 4 And a collection tank 6 for collecting the natural surfactant cleaning liquid.

  After discharging the supernatant liquid (natural surfactant cleaning liquid) in the recovery tank 6 to the cleaning waste liquid storage tank 15, the second stage decontamination is performed.

  In the second stage decontamination, a nanobubble cleaning liquid storage tank 8 for supplying a predetermined amount of carbonic acid nanobubble cleaning liquid into a collection tank 6 storing the soil 7 after the first stage decontamination, and soil 7 mixed with the carbonic acid nanobubble cleaning liquid are used. A second-stage cavitation jet type washing machine 9 to be washed and a second-stage plunger pump 10 for supplying driving high-pressure water connected to the second-stage cavitation jet type washing machine 9 are configured.

  The carbonic acid nanobubble cleaning liquid is produced by the nanobubble generator 12 to which the carbon dioxide gas cylinder 11 is connected. The first stage plunger pump 5 and the second stage plunger pump 10 are connected to a water storage tank 13.

  The soil 7 and the carbonated nanobubble cleaning liquid that have passed through the second-stage cavitation jet cleaning machine 9 are transferred to the wet classifier 14. In the wet classifier 14, it classifies into the soil of 75 micrometers or more and the soil of less than 75 micrometers.

  The soil of less than 75 μm classified by the wet classifier 14 is purified as a washing waste liquid together with the suspended water. The cleaning treatment of the cleaning waste liquid includes a cleaning waste liquid storage tank 15 that receives the suspended water transferred from the wet classifier 14, a suspension water processing machine 16 that coagulates and precipitates the cleaning waste liquid, and an aggregation adsorption connected to the suspension water processing machine 16. And a precipitating agent supply unit 17.

(Execution of decontamination)
Using the apparatus shown in FIG. 1, decontamination of soil contaminated with radioactive substances was performed. Cs-134 and Cs-137 were detected from the soil 1 before decontamination, and the total concentration was 750 Bq / kg. As a result of measuring the particle size distribution, 15% of the particles were less than 75 μm and 85% were 75 μm or more.

  FIG. 2 shows a soil decontamination method. The decontamination procedure is as follows.

1. In the cleaning liquid storage tank 2, 90 L of a cleaning liquid containing 0.01% of a natural surfactant whose main component is surfactin sodium is prepared.
2. 30 kg of soil 1 and 90 L of a natural surfactant cleaning solution are charged into the supply tank 3.
3. The first-stage plunger pump 5 is activated and 15 MPa of driving high-pressure water is supplied to the first-stage cavitation jet cleaning machine 4.
4). Since the inside of the pipe 3a connected between the supply tank 3 and the first stage cavitation jet type washing machine 4 becomes negative pressure, the soil 1 and the natural surfactant washing liquid in the supply tank 3 are transferred to the cavitation jet type washing machine 4. Sucked into. Cavitation occurs in the cavitation jet cleaning machine 4, and the soil 1 is ground, crushed and washed in the cleaning liquid while passing through the cavitation jet cleaning machine 4.

5. The soil 1 and the natural surfactant cleaning liquid that have passed through the first-stage cavitation jet cleaning machine 4 are recovered in the recovery tank 6.
6). The supernatant liquid (natural surfactant cleaning liquid) in the recovery tank 6 is transferred to the cleaning waste liquid storage tank 15. Soil fine particles (less than 75 μm) floating in the natural surfactant cleaning liquid are also transferred to the cleaning waste liquid storage tank 15.
7). While supplying carbon dioxide gas from the carbon dioxide gas cylinder 11 to the nanobubble generator 12, water in the nanobubble cleaning liquid storage tank 8 is circulated to the nanobubble generator 12, and 90 L of carbonic acid nanobubble cleaning liquid is produced in the nanobubble cleaning liquid storage tank 8. In this example, since the nanobubble water generation amount of the nanobubble generator 12 is 4 L / min, the supply amount of carbon dioxide gas is 2.5% (0.1 L / min) with respect to the nanobubble water generation amount. is there.
8). 90 L of carbonic acid nanobubble cleaning liquid is put into the collection tank 6.

9. The second-stage plunger pump 10 is activated and 15 MPa of driving high-pressure water is supplied to the second-stage cavitation jet cleaning machine 9.
10. Since the pipe 6a connected between the recovery tank 6 and the second stage cavitation jet type washing machine 9 has a negative pressure, the soil 7 and the carbonated carbon nanobubble cleaning liquid in the recovery tank 6 are in the second stage cavitation jet type washing machine. 9 sucked. Cavitation occurs in the second-stage cavitation jet cleaning machine 9, and the soil 7 is ground, crushed and washed in the cleaning liquid while passing through the second-stage cavitation jet cleaning machine 9. Moreover, the natural surfactant covering the soil surface is rinsed with a carbonic acid nanobubble cleaning solution.
11. The soil 7 and the carbonic acid nanobubble cleaning liquid that have passed through the second stage cavitation jet cleaning machine 9 are transferred to the wet classifier 14.
12 The wet classifier 14 classifies the soil after washing into soil having a size of less than 75 μm and soil having a size of 75 μm or more, and separates a washing waste liquid containing soil having a size less than 75 μm.
13. Measure the radioactivity concentration of soil of 75μm or more.

  As a result of decontamination by the above procedure, the total concentration of Cs-134 and Cs-137 in the soil of 75 μm or more was 80 Bq / kg. Further, 25 kg of soil having a size of 75 μm or more was recovered, and the recovery rate of soil after decontamination was 83%.

  From the above, it was found that the decontamination method of the present invention can decontaminate soil contaminated with radioactive cesium to 100 Bq / kg or less.

  A feature of the decontamination method of the present invention is that a natural surfactant cleaning solution and a carbonic acid nanobubble cleaning solution are applied to the cleaning solution. The natural surfactant cleaning liquid expands once when it is sucked into the first stage cavitation jet cleaning machine 4 under negative pressure, but the volume shrinks in the first stage cavitation jet cleaning machine 4 at high pressure (15 MPa). To do. Due to the expansion and contraction of the volume, the micelle (natural surfactant aggregate) of the natural surfactant is made ultrafine. On the other hand, the soil is ground and crushed in the first stage cavitation jet washer 4 so that some of the coarse particles become fine particles or ultrafine particles. Since the surface of these particles is covered with a natural surfactant (for example, the surface of ultrafine particles is covered with ultrafine micelles), the repulsive coarse particles of 75 μm or more settle in the washing liquid, and the fine particles of less than 75 μm and The ultrafine particles float in the cleaning liquid, so that it becomes easy to separate the soil particles of 75 μm or more and the soil particles of less than 75 μm.

  Further, the carbonic acid nanobubble cleaning liquid is sucked into the second-stage cavitation jet cleaning machine 9 with a negative pressure, passes through the high-pressure (15 MPa) second-stage cavitation jet cleaning machine 9, and is released to atmospheric pressure. Because the air introduced from the outside and carbon dioxide in the cleaning liquid coexist in the second stage cavitation type washing machine 9, cavitation with a large destructive force is generated by repeating generation and disappearance of a large number of bubbles with pressure fluctuation. The soil is then ground and crushed.

  Due to the above phenomenon, the soil of 75 μm or more is strongly decontaminated, and the radioactive cesium concentration is considered to have decreased to 100 Bq / kg or less.

  In the Ministry of the Environment Notification No. 76, the average radioactive cesium concentration of products recycled from disaster waste caused by the Great East Japan Earthquake is set to 100 Bq / kg or less before being put on the market.

  In addition, it was confirmed that the radioactive cesium concentration can be decontaminated to 100 Bq / kg or less by using the decontamination method of the present invention for the timber and the fallen leaves that are made into chips.

  Therefore, by applying the decontamination method of the present invention, it is possible to recycle more than 80% of soil and thinned wood contaminated with radioactivity, so that the amount of disaster waste stored can be greatly reduced. And reuse for construction materials is promoted.

  Independent administrative agency Japan Atomic Energy Agency (JAEA) received the “Decontamination Demonstration Project in Evacuation Zones, etc. Related to the Fukushima Daiichi Nuclear Power Station Accident” commissioned by the Cabinet Office. Was carried out. In addition, Fukushima Prefecture independently conducted a “decontamination technology demonstration project field test” in FY2011. The test results are posted on the JAEA and Fukushima Prefecture websites. Soil decontamination results are also listed, but none of the decontamination techniques have been decontaminated to 100 Bq / kg or less.

  Therefore, the decontamination method of the present invention is the only technique capable of decontaminating radioactively contaminated soil to 100 Bq / kg or less.

  Although the examples of decontamination have described in detail preferred embodiments of the present invention, the present invention is not limited to specific embodiments, and is within the scope of the gist of the present invention described in the claims. Needless to say, various modifications and changes are possible.

  The decontamination conditions include a natural surfactant concentration of 0.01 to 0.1%, a carbon dioxide gas supply amount of 2.5 to 100% of the nanobubble generation amount when producing a carbonated nanobubble cleaning solution, and a plunger pump drive It was confirmed that decontamination can be performed to 100 Bq / kg or less when the pressure of the high pressure water for use is in the range of 15 to 25 MPa. Moreover, a vibration sieve device or a high mesh separator can be applied to the classification of the soil after washing and the separation of the washing liquid.

(Implementation of cleaning waste liquid treatment)
FIG. 3 shows a cleaning waste liquid purification procedure. The purification procedure is as follows.

1. The cleaning waste liquid of the wet classifier 14 is transferred to the cleaning waste liquid storage tank 15.
2. The cleaning waste liquid in the cleaning waste liquid storage tank 15 is transferred to the suspension water treatment machine 16.
3. Aggregated adsorptive precipitant (including binos powder) is added to the washing waste liquid of the suspension water treatment machine 16 from the aggregate adsorbent / precipitant supply unit 17 at 0.3 g / L.
Radioactive material and soil fine particles are aggregated and adsorbed in 4.5 to 10 minutes.
5. Separated into precipitate and filtrate by filter cloth.
6). Measure the radioactivity concentration of the filtrate.
7). Confirm that the radioactivity concentration of the filtrate is below the standard value of the Ministry of the Environment shown below, and reuse it as a cleaning solution.
Cs-134 concentration (Bq / L) / 60 (Bq / L) + Cs-137 concentration (Bq / L) / 90 (Bq / L) ≦ 1
8). Measure and store the radioactive concentration of sediment (sludge).

  As a result of purifying the cleaning waste liquid by the above procedure, the concentration of radioactive cesium in the filtrate was below the lower limit of detection (20 Bq / L). Further, the COD concentration of the filtrate was 20 mg / L or less. The amount of cleaning waste liquid subjected to the purification treatment was 450 L.

  10 kg of sediment (sludge) was recovered, and the radioactive cesium concentration was 1,000 Bq / kg.

  The aggregated adsorbing precipitant is 10 to 25% by weight of binos powder obtained by drying Parachlorella sp. Binos, 20 to 25% by weight of aluminum sulfate, gypsum and / or sodium carbonate weight of 30 to 30%. 40%, diatomaceous earth 8 to 15% by weight, alkaline substance 15 to 20% by weight such as soda ash, and polymer flocculant weight 1 to 7%. Parachlorella binos refers to Parachlorella microalgae capable of producing alginic acid, and the applicant (Bainos Co., Ltd.) filed an international application to provide useful new Parachlorella microalgae and methods for using the same ( WO2010 / 024367).

  From the above, it was found that the aggregated adsorbing precipitant containing binos powder can purify the radioactive cesium concentration in the washing waste liquid below the detection lower limit value. It was also found that the COD concentration in the cleaning waste liquid can be reduced to 20 ppm or less because the natural surfactant is also aggregated and adsorbed.

  Therefore, since the cleaning waste liquid after the purification treatment can be reused as cleaning water, in principle, no radioactive liquid waste is generated. Even if the purified waste liquid is discharged, the radioactive substance concentration is not more than the detection lower limit value, and the COD concentration is not more than 20 ppm.

  In addition, although the Example of the decontamination waste liquid processing explained in detail about the preferred embodiment of the present invention, the present invention is not limited to the specific embodiment, and the gist of the present invention described in the claims is described. It goes without saying that various modifications and changes can be made within the range. It was confirmed that the concentration of radioactive cesium in the waste liquid for purification treatment was not more than the detection lower limit value and the COD concentration was not more than 20 ppm in the range of addition amount of 0.1 to 0.5 g / L for the aggregated adsorbing precipitant containing binos powder.

(effect)
In the Example of this invention, the natural soil and the carbonic acid nano bubble washing | cleaning liquid were used for washing | cleaning liquid, and the contaminated soil was decontaminated with the cavitation jet type washing machine. In addition, the cleaning waste liquid after decontamination was purified with an agglomerated adsorptive precipitant containing binos powder. The effects of the present invention are as follows.

(1) Soil after decontamination, chipped timber and fallen leaves have a radioactive cesium (total of Cs-134 + Cs-137) concentration reduced to 100 Bq / kg or less. Can be reused.

(2) Since 80% or more of the decontaminated soil of 100 Bq / kg or less can be recovered, the amount of disaster waste stored can be greatly reduced and reused.

(3) The cleaning waste liquid subjected to the purification treatment can be reused as cleaning water because the radioactive cesium concentration is not more than the detection lower limit value and the COD is not more than 20 mg / L.

(4) When the cleaned cleaning waste liquid is discharged, the radioactivity concentration is not more than the detection lower limit value and the COD is not more than 20 mg / L, so there is no influence on the environment.

1: Soil before decontamination 2: Washing liquid storage tank 3: Supply tank 4: First stage cavitation jet washing machine 5: First stage plunger pump 6: Recovery tank 7: Soil after first stage decontamination 8: Nano bubble washing liquid storage tank 9: Second stage cavitation jet type washing machine 10: Second stage plunger pump 11: Carbon dioxide gas cylinder 12: Nano bubble generator 13: Water storage tank 14: Wet classifier 15: Washing waste liquid storage tank 16: Suspended water treatment machine 17: Aggregation adsorption precipitant supply section

Claims (8)

  In a decontamination method of a decontaminated object contaminated with a radioactive substance, a cavitation jet cleaning is performed using a natural surfactant cleaning liquid, followed by a cavitation jet cleaning using a carbonic acid nanobubble cleaning liquid. Decontamination method for contaminated objects to be decontaminated.   Natural surfactant cleaning liquid adjustment process, cavitation jet cleaning process using natural surfactant as cleaning liquid, carbonated nanobubble cleaning liquid adjustment process, cavitation jet cleaning process using carbonated nanobubble water, and decontaminated product And a step of classifying the suspension into water (including radioactive substances and fine particles), a step of aggregating and precipitating radioactive substances and fine particles in the suspension water with an agglomeration adsorbing precipitant, and separating the precipitate and the water to be treated; The method for decontamination of a decontaminated material contaminated with a radioactive substance according to claim 1, wherein the water to be treated is reused as cleaning water for decontamination.   3. The removal of a decontaminated material contaminated with a radioactive substance according to claim 1 or 2, wherein the natural surfactant concentration of the natural surfactant cleaning liquid is in the range of 0.01 to 0.1%. Dyeing method.   The carbonic acid nanobubble cleaning liquid is produced by supplying carbon dioxide gas to the nanobubble generator in a range of 2.5 to 100% with respect to the nanobubble water generation amount (L / min) of the nanobubble generator. The decontamination method of the to-be-decontaminated thing contaminated with the radioactive substance of Claim 1 or 2.   The high-pressure water for driving of 15 to 25 MPa is supplied to the cavitation jet cleaning process using the natural surfactant as a cleaning liquid and the cavitation jet cleaning process using the carbonated nanobubble water as a cleaning liquid. Or the decontamination method of the to-be-decontaminated material contaminated with the radioactive substance of 2.   3. The method for decontamination of a decontaminated material contaminated with a radioactive substance according to claim 2, wherein the coagulation adsorbing precipitant contains binos powder obtained by drying Parachlorella sp. Binos. .   The method for decontamination of a decontaminated object contaminated with a radioactive substance according to claim 2 or 6, wherein the agglomerated adsorbing precipitant is added in an amount of 0.1 to 0.5 g / L to the cleaning waste liquid after decontamination. .   In a decontamination system for decontaminated materials contaminated with radioactive substances, a cleaning liquid storage tank that adjusts and stores a natural surfactant cleaning liquid, a cleaning machine that uses a natural surfactant as a cleaning liquid and a cavitation jet cleaning, and a natural surfactant cleaning liquid A recovery tank for recovering the decontaminated material, a nanobubble cleaning liquid storage tank for adjusting and storing the carbonic acid nanobubble cleaning liquid, a washing machine for cavitation jet cleaning using carbonic acid nanobubble water as the cleaning liquid, and the decontaminated material and suspended water (radioactive substances and fine water). (Including particles), a washing waste liquid storage tank that collects suspended water, and agglomerated adsorptive precipitants that aggregate and adsorb the radioactive substances and fine particles in the suspended water to separate the precipitate and the water to be treated. A decontamination system for an object to be decontaminated by a radioactive material, comprising a suspension water treatment machine.

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