JP5946658B2 - Radioactivity decontamination system and radioactivity decontamination method - Google Patents

Description

  The present invention relates to a radioactivity decontamination system and radioactivity decontamination method, and in particular, a radioactivity decontamination system and radioactivity suitable for removing and reducing radioactivity contamination in a vast natural environment such as a mountain, forest, plateau, and satoyama. It relates to a decontamination method.

  Radioactive contamination in a vast natural environment such as mountains, forests, plateaus, and satoyama can be distinguished from low-dose contamination because it is generally thin and easy to spread. However, if the total dose of a vast area is summed up, it becomes a huge dose, a hot spot (a place where the radiation dose is locally high) occurs depending on the weather conditions when the radiation dust falls, and natural conditions such as rain In view of the occurrence of hot spots naturally concentrated in the downstream area due to purification, it is not preferable to leave radioactive contamination in a vast natural environment such as mountains, forests, plateaus, satoyama, etc.

  In particular, when radioactive materials in a vast natural environment are left unattended, natural purification can be expected by rain and snow, but contaminated water containing radioactive materials may flow into rivers and groundwater, causing ocean pollution and human pollution.

  By the way, radioactive decontamination in a narrow area such as a building or a hot spot is generally treated by collecting pollutants or washing with high-pressure water. However, a method that can decontaminate the entire vast natural environment is now available. I can't find it. For example, Patent Document 1 collects polluted water containing suspended particle components that have fallen on the ground surface by spraying mist-like water in the air with a sprinkler and dropping suspended particles that remain in the air onto the ground surface. However, it is not practical to arrange such a watering device so as to fill a large area.

JP 2002-191922 A

  As described above, when the area of radioactive contamination is vast, for example, it is conceivable to perform radioactive decontamination as an emergency decontamination target in places where people go in and out, near houses, farmland, and the like. However, in places adjacent to the natural environment such as mountains, forests, plateaus, and satoyama, radiation doses may increase again due to weather conditions, natural concentration, and the like.

  In addition, in the natural environment such as mountains, forests, plateaus, and satoyama, when collecting contaminated soil or cutting contaminated plants, securing a place to store the collected materials, generating landslide disasters, reducing the volume of incineration facilities, etc. Problems, such as the necessity of a conversion process, will arise.

  The present invention was devised in view of the above-mentioned problems, and can remove and reduce radioactive contamination in a vast natural environment, and can reduce radioactive contamination in the downstream area. An object is to provide a dyeing system and a radioactive decontamination method.

  ADVANTAGE OF THE INVENTION According to this invention, it is a radioactive decontamination system which removes or reduces the radioactive contamination in a natural environment, Comprising: It is formed in the location where a radioactive substance tends to accumulate, and a dam with a sediment layer and rain water flow easily A damming wall formed at a location, a road and a side groove formed along the damming wall, a water channel for collecting contaminated water flowing into the side groove, and a contaminated water purification apparatus connected to the water channel. The contaminated water that has flowed into the gutter is decontaminated by the contaminated water purification device, and the radioactive material accumulated in the sediment layer of the dam is recovered by exchanging the sediment layer. A radioactive decontamination system is provided.

The dam is a clay layer disposed on a depression formed in the ground, an earth and sand layer disposed on the clay layer, and a wall member disposed on the downstream side where rainwater flows in the dam. , May be included. Moreover, it has a reservoir formed adjacent to the sabo dam, and the reservoir may be connected to the water channel.

  The polluted water purification apparatus includes a mud separation tank that precipitates and removes mud from the contaminated water, a radioactive decontamination filter that adsorbs and removes radioactive substances from the primary treated water that has passed through the mud separation tank, and the radioactive decontamination A precipitation separation tank that removes impurities from the secondary treated water that has passed through the filter, a water storage tank that stores the tertiary treated water that has passed through the precipitation separation tank, and a radioactivity detector disposed in the water storage tank, When the measurement value of the radioactivity detector is not more than a predetermined threshold value, tertiary treated water may be drained from the water storage tank into the natural environment.

  Moreover, according to this invention, it is a radioactive decontamination method which removes or reduces the radioactive contamination in a natural environment, Comprising: A dam with a sediment layer is formed in the place where a radioactive substance tends to accumulate, and rainwater flows easily Forming a damming wall at a location, forming a gutter along the road and the damming wall, collecting and decontaminating contaminated water flowing into the gutter, and exchanging the soil layer of the dam A radioactive decontamination method is provided, wherein the radioactive material accumulated in the sediment layer is recovered.

  According to the radioactivity decontamination system and the radioactivity decontamination method according to the present invention described above, the location where the sediment is collected at the location where the radioactivity is likely to accumulate (so-called hot spot), and the location where the rainwater easily flows. By disposing the damming walls and the side grooves, it is possible to easily collect radioactive substances that tend to stay in a specific location, and it is possible to collect and easily decontaminate radioactive substances that are easily washed away by rainwater. Therefore, by applying the radioactive decontamination system and the radioactive decontamination method according to the present invention to a vast natural environment such as a mountain, forest, plateau, satoyama, etc., the radioactive contamination of the vast natural environment is removed and reduced. And radioactive contamination in the downstream area can be effectively suppressed.

  In particular, since radioactive materials can be recovered upstream in a vast natural environment, the amount of radioactive material diffusing downstream can be reduced, hot spots can be generated in locations close to the isolator, groundwater radiation And pollution of rivers and oceans can be effectively suppressed.

1 is an overall configuration diagram showing a radioactive decontamination system according to an embodiment of the present invention. It is detailed explanatory drawing of the dam with the dam shown in FIG. 1, (A) is sectional drawing, (B) has shown the top view. FIG. 2 is a detailed explanatory view of the damming wall shown in FIG. It is detailed explanatory drawing of the radioactive purification apparatus shown in FIG. 1, (A) is a whole block diagram, (B) has shown the contaminated water treatment system diagram.

  Hereinafter, embodiments of the radioactivity decontamination system and radioactivity decontamination method according to the present invention will be described with reference to FIGS. Here, FIG. 1 is an overall configuration diagram showing a radioactive decontamination system according to an embodiment of the present invention.

  As shown in FIG. 1, the radioactive decontamination system according to the embodiment of the present invention is a radioactive decontamination system that removes or reduces radioactive contamination in the natural environment, and is formed in a place where radioactive substances tend to accumulate. In addition, the dam 1 including the sediment layer 13, the dam wall 2 formed at a place where rainwater easily flows, the side groove 3 formed along the road 3 a and the dam wall 2, and the contamination flowing into the side groove 3 The polluted water which has the water channel 4 which collects water, and the contaminated water purification apparatus 5 connected to the water channel 4 and flows into the side groove 3 is decontaminated by the contaminated water purification apparatus 5 and The radioactive material absorbed in the earth and sand layer 13 is recovered by exchanging the earth and sand layer 13.

  The radioactivity decontamination system shown in FIG. 1 has a reservoir 7 formed adjacent to the sabo dam 6, and the reservoir 7 is connected to the water channel 4. It is assumed that a river 8 flows downstream of the reservoir 7.

  The radioactive decontamination system described above is intended to remove and reduce radioactive contamination in a vast natural environment such as mountains, forests, plateaus, and satoyama. Therefore, in the vast natural environment such as mountains, forests, plateaus, satoyama, etc., the dam 1, the dam wall 2 and the gutter 3 correspond to the size of the natural environment area, the level of radioactive contamination, the geography and topography of the natural environment. Are arranged.

  The dam 1 has a function for removing or reducing radioactive contamination at a place where radioactive substances are easily accumulated, such as a hot spot. Since the radioactive material in the hot spot stays in the place, it is gradually concentrated by natural purification such as rainwater to form a highly concentrated contaminated area. Therefore, in the present invention, the dam 1 is formed in advance at a place where a hot spot is easily formed, the radioactive material is actively accumulated, and the accumulated radioactive material is collected together with the earth and sand. The place where the dam 1 is formed may be a hot spot discovered by a radiation measuring device (Geiger counter), or a spot where radioactive materials are likely to accumulate geographically or topographically. However, it may be a spot where it is desired to intentionally form a place where radioactive substances are likely to accumulate positively.

  Here, FIG. 2 is a detailed explanatory view of the cough pond shown in FIG. As shown in FIGS. 2 (A) and 2 (B), the dam 1 includes, for example, a clay layer 12 disposed on a depression 11 formed on the ground and earth and sand disposed on the clay layer 12. It has the layer 13 and the wall member 14 arrange | positioned in the downstream from which rainwater flows. In addition, on the outer periphery of the dam 1, a rope 16 hung over the support column 15 may be arranged in order to make it clear that the area is prohibited from entering.

  The depression 11 has, for example, an inclined portion 11a that smoothly curves the upstream side through which rainwater flows, and the wall member 14 is disposed on the downstream side. The clay layer 12 has a function of forming a poorly permeable layer on the depression 11 and suppressing the penetration of contaminated water containing a radioactive substance into the underground. The earth and sand layer 13 is a layer having water permeability, and has a function of retaining the contaminated water that has flowed in and suppressing the diffusion of radioactive substances. The wall member 14 is comprised by the crosspiece 14a laminated | stacked on the clay layer 12, and the pile 14b which supports the crosspiece 14a, for example. The wall member 14 can suppress the sediment outflow of the sediment layer 13.

  By forming the dam 1 in the natural environment, radioactive materials can be accumulated in the sediment layer 13, and the radioactive material can be easily recovered simply by replacing the sediment in the sediment layer 13. Radioactive material can be removed. The earth and sand may be exchanged when, for example, the radiation dose measured by a radiation measuring instrument (Geiger counter) exceeds a predetermined threshold, or regularly exchanged every few days or weeks. It may be. The collected earth and sand may be stored and stored in a radioactive waste storage container capable of shielding radiation, or may be subjected to decontamination treatment to remove radioactive substances, or may be incinerated. It may be stored after volume reduction processing.

  The said dam wall 2 has a function for keeping the radioactive substance carried away by rainwater, and suppressing the spreading | diffusion of the radioactive contamination to a downstream area. In general, radioactive substances adhering to the ground, trees, buildings, etc. tend to be naturally purified by rain, snow, etc. and diffused downstream. In natural environments such as mountains, forests, plateaus, satoyama, etc., rainwater passes through the downstream by selecting a place where it can easily pass, so the path of rainwater is easily identified topographically. Therefore, a damming wall 2 is arranged to block the path of the rainwater and suppress the diffusion of contaminated water containing radioactive substances to the downstream area.

  Here, FIG. 3 is a detailed explanatory view of the damming wall shown in FIG. 1, (A) is a sectional view, and (B) is a plan view showing an arrangement method. As shown in FIGS. 3A and 3B, the damming wall 2 is constituted by a concrete wall member embedded in the ground on the rainwater passage 2a and extending to the ground. The dam wall 2 may be made of steel, but is preferably made of concrete in consideration of corrosion and the like. From the viewpoint of construction, the damming wall 2 is formed to have a size of about 1 to 2 m above ground height and about 5 to 10 m wall length, for example.

  A side groove 3 is formed on the upstream side of the damming wall 2. The side groove 3 supplies, for example, a concrete groove member 31 embedded in the ground, a lid member 32 having an opening disposed on the groove member 31, and water flowing into the groove member 31 to the water channel 4. And a drain pipe 33. Thus, by arranging the damming wall 2 and the side groove 3 on the rainwater passage 2a, the tainted water that passes through the rainwater passage 2a can be stopped by the damming wall 2 and the flow is blocked ( Rainwater containing radioactive material) flows into the side grooves 3. The contaminated water flowing into the side groove 3 is supplied to the water channel 4 and removed from the natural environment.

  In FIG. 3 (A), the drain pipe 33 is formed so as to penetrate the retaining wall 2, but is not limited to such a configuration. For example, when the side groove 3 has a certain distance, The drain pipe 33 may be connected to the downstream end. Further, as shown in FIG. 3B, the damming walls 2 and the side grooves 3 may be distributed and arranged for each rainwater passage 2a, or a plurality of rainwater passages 2a may be blocked. You may make it arrange | position to. However, if the retaining wall 2 is formed long, the construction is difficult and expensive, and therefore the retaining wall 2 may be partially disposed at a necessary location even when the side groove 3 is disposed long.

  By the way, the side groove 3 may be arranged not only on the upstream side of the above-described retaining wall 2 but also on the existing or new road 3a as shown in FIG. In this case, as illustrated, the side grooves 3 are preferably arranged at least on the downstream side of the road 3a, and the side grooves 3 may be arranged on both sides of the road 3a. Since the configuration of the side groove 3 is the same as that shown in FIG. 3A, detailed description thereof is omitted here.

  In a natural environment having a steep slope such as a mountain, a sabo dam 6 may be formed. The rainwater overflowing from the sabo dam 6 is collected by a reservoir 7 arranged on the downstream side of the sabo dam 6 and supplied to the water channel 4. You may make it newly install the sabo dam 6 and the reservoir 7 in the location which has the steep slope where the sabo dam 6 is not formed. It can also be said that the sabo dam 6 is obtained by increasing the size of the retaining wall 2.

  The contaminated water (rain water containing radioactive substances) collected in the side groove 3 and the reservoir 7 is conveyed to the contaminated water purification device 5 through the water channel 4. Here, FIG. 4 is a detailed explanatory diagram of the radioactivity purification apparatus shown in FIG. 1, (A) shows an overall configuration diagram, and (B) shows a contaminated water treatment system diagram.

  As shown in FIG. 4 (A), the contaminated water purification apparatus 5 has a mud separation tank 51 that precipitates and removes mud from the contaminated water, and radiation that adsorbs and removes radioactive substances from the primary treated water that has passed through the mud separation tank 51. Active decontamination filter 52, precipitation separation tank 53 for removing impurities from secondary treated water that has passed through radioactive decontamination filter 52, water storage tank 54 for storing tertiary treated water that has passed through precipitation separation tank 53, and water storage tank 54 And when the measured value of the radioactivity detector 55 is equal to or lower than a predetermined threshold value, the tertiary treated water is drained from the water storage tank 54 into the natural environment. ing.

  As shown in FIG. 4 (B), the water channel 4 includes a plurality of branch water channels 41 connected to the side grooves 3 and the reservoirs 7 disposed in the natural environment, a main water channel 42 in which the branch water channels 41 are aggregated, And a water supply channel 43 connected to the contaminated water purification device 5 from the main water channel 42. The branch water channel 41 is buried and stretched underground, and is connected to a surrounding drainage system (such as the gutter 3 and the reservoir 7). The main waterway 42 is a large tunnel waterway that integrates all drainage systems. In addition, in the case where the amount of drainage temporarily increases due to guerrilla heavy rain or the like, a water storage tank for storing the wastewater transported to the main water channel 42 may be arranged.

  In addition, a plurality of contaminated water purification devices 5 are connected to the water channel 4 via a water supply channel 43, and the contaminated water (rainwater containing radioactive material) conveyed to the main water channel 42 is sequentially contaminated water purification device. 5 to be decontaminated. The decontaminated water (tertiary treated water) is finally discharged from the drain pipe 56 into a natural environment such as a river. In addition, you may make it arrange | position a flow control valve in the branch water channel 41 and the water supply channel 43 of the water channel 4 as needed.

  The contaminated water (rain water containing radioactive substances) supplied to the contaminated water purification apparatus 5 is first put into the mud separation tank 51. The drainage from the gutter 3 and the reservoir 7 described above contains many impurities such as mud, fallen leaves, and dust. Therefore, in the mud separation tank 51, impurities such as mud having a heavy specific gravity are mainly precipitated and separated from the waste water. Since the sediment may contain radioactive substances, the sediment is periodically collected and subjected to processing such as storage, incineration, and decontamination. Light impurities such as fallen leaves and dust may be removed by passing the filter through a filter such as a wire mesh before the wastewater is put into the mud separation tank 51. Since these recovered materials may contain radioactive substances, the precipitates are periodically recovered and subjected to processing such as storage, incineration, and decontamination.

  The primary treated water that overflows from the mud separation tank 51 passes through a radioactive decontamination filter 52 that is disposed adjacent to the primary treated water, thereby adsorbing and removing radioactive substances contained in the primary treated water. The radioactive decontamination filter 52 is a filter capable of adsorbing a radioactive substance such as cesium, for example, and a commercially available filter can be used. The radioactive decontamination filter 52 is periodically replaced, and the used radioactive decontamination filter 52 is stored in a radioactive waste storage container or the like after incineration, for example. In order to actively pass the primary treated water through the radioactive decontamination filter 52, a circulation pump (not shown) may be arranged in the same water tank as the radioactive decontamination filter 52.

  The sedimentation separation tank 53 is a step of further purifying the secondary treated water from which radioactive substances have been removed by the radioactive decontamination filter 52, and is often arranged in multiple stages as shown in the figure. In each of the precipitation separation tanks 53, only the water that flows over the wall surface portion (weir) is supplied to the downstream side, and a substance having a high specific gravity is precipitated and separated in each tank. Since the sediment may contain radioactive substances, the sediment is periodically collected and subjected to processing such as storage, incineration, and decontamination.

  The wastewater that has passed through the sedimentation separation tank 53 is supplied to the water storage tank 54 via, for example, a pumping pump 53a. A drain pipe 56 having a drain pump 56a and a flow control valve 56b is connected to the water storage tank 54. In addition, a radioactive detector 55 is disposed in the water storage tank 54, and the radiation dose in the water storage tank 54 is constantly or regularly monitored. And when the measured value of the radiation detector 55 is below a predetermined threshold value, the flow control valve 56b is opened, the drain pump 56a is operated, and the tertiary treated water is released from the water storage tank 54 into the natural environment. The threshold value of the radioactivity detector 55 is set to 0.23 μSv / h or less, which is an air dose rate per hour converted from an annual exposure dose of 1 mSv or less, for example.

  According to the radioactivity decontamination system described above, the dam 1 is provided with the sediment layer 13 where radioactive substances tend to accumulate, the dam wall 2 is formed where rainwater easily flows, and the road 3a and the dam 2 In addition to collecting and decontaminating contaminated water that has flowed into the side groove 3, the radioactive material accumulated in the sediment layer 13 can be removed by periodically exchanging the sediment layer 13 of the dam 1 It is possible to easily carry out the radioactive decontamination method to be collected.

  According to the radioactivity decontamination system and radioactivity decontamination method according to the above-described embodiment, the dam 1 is disposed at a place where radioactivity is likely to accumulate (so-called hot spot), and rainwater flows. By arranging the damming walls 2 and the side grooves 3 at easy places, it is possible to easily collect radioactive substances that tend to stay in specific places, and to easily decontaminate radioactive substances that are easily washed away by rainwater. Can do. Therefore, by applying the radioactivity decontamination system and radioactivity decontamination method described above to a vast natural environment such as mountains, forests, plateaus, and satoyama, it is possible to remove and reduce the radioactivity contamination of the vast natural environment. And radioactive contamination in the downstream region can be effectively suppressed.

  In particular, since radioactive materials can be recovered upstream in a vast natural environment, the amount of radioactive material diffusing downstream can be reduced, hot spots can be generated in locations close to the isolator, groundwater radiation And pollution of rivers and oceans can be effectively suppressed.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, such as being able to be applied as appropriate in a vast natural environment such as mountains, forests, plateaus, and satoyama. Of course.

DESCRIPTION OF SYMBOLS 1 Coughing pond 2 Coughing wall 2a Road 3 Side gutter 3a Road 4 Water channel 5 Contaminated water purification apparatus 6 Sabo dam 7 Reservoir 8 River 11a Inclined part 12 Clay layer 13 Sediment layer 14 Wall member 14a Cross bar 14b Pile 15 Strut 16 Rope 31 Groove member 32 Lid member 41 Drain pipe 41 Branch water channel 42 Main water channel 43 Water supply channel 51 Mud separation tank 52 Radioactive decontamination filter 53 Sedimentation separation tank 53a Pumping pump 54 Water tank 55 Radioactivity detector 56 Drain pipe 56a Drain pump 56b Flow control valve

Claims (5)

A radioactive decontamination system that removes or reduces radioactive contamination in the natural environment,
A dam with a sediment layer that is formed in a place where radioactive substances tend to accumulate,
A damming wall formed in a place where rainwater easily flows,
Gutters formed along the road and the retaining wall;
A water channel for collecting contaminated water flowing into the gutter,
A contaminated water purification device connected to the water channel,
The contaminated water that has flowed into the gutter is decontaminated by the contaminated water purification device, and the radioactive material accumulated in the sediment layer of the dam is collected by replacing the sediment in the sediment layer. Radioactive decontamination system characterized by that. The dam is a clay layer disposed on a depression formed in the ground, an earth and sand layer disposed on the clay layer, and a wall member disposed on the downstream side where rainwater flows in the dam. The radioactive decontamination system according to claim 1, wherein   The radioactive decontamination system according to claim 1, further comprising a reservoir formed adjacent to the sabo dam, the reservoir being connected to the water channel.   The polluted water purification apparatus includes a mud separation tank that precipitates and removes mud from the contaminated water, a radioactive decontamination filter that adsorbs and removes radioactive substances from the primary treated water that has passed through the mud separation tank, and the radioactive decontamination A precipitation separation tank that removes impurities from the secondary treated water that has passed through the filter, a water storage tank that stores the tertiary treated water that has passed through the precipitation separation tank, and a radioactivity detector disposed in the water storage tank, The radioactivity decontamination system according to claim 1, wherein when the measurement value of the radioactivity detector is equal to or less than a predetermined threshold value, the tertiary treated water is drained from the water storage tank into a natural environment. A radioactive decontamination method for removing or reducing radioactive contamination in the natural environment,
Form a dam with a sediment layer in a place where radioactive substances tend to accumulate,
Form a damming wall where rainwater easily flows,
Forming a gutter along the road and the retaining wall,
Concentrating and decontaminating the contaminated water that flowed into the gutter, and collecting radioactive material accumulated in the sediment layer by exchanging the sediment of the sediment layer of the dam
A radioactive decontamination method characterized by that.