JP7525418B2 - Dismantling and removal method and dismantling and removal device - Google Patents

Description

This disclosure relates to a method and device for dismantling and removing highly radioactive concrete.

Various methods and devices for dismantling and removing highly radioactive concrete have been known for some time. JP-B-2-62036 describes a dismantling system for dismantling a cylindrical concrete heat shield wall inside a concrete biological shield in a nuclear reactor. The concrete biological shield has a top opening and a roof seal that seals the top opening.

The roof seal ensures that the inside and outside of the concrete biological shield are at equal pressure, while preventing slag and dust generated during the concrete cutting process from leaking out to the outside. A main shaft is installed at the center of the thermal shield. The main shaft is supported by upper and lower support devices installed inside the concrete biological shield. A rotating device is attached to the main shaft, and a plasma cutter is installed on the rotating device. The plasma cutter is a device that dismantles the thermal shielding wall, and dismantles it into blocks. The thermal shielding wall cut into blocks is disposed of as waste.

Special Publication No. 2-62036

When breaking down concrete into blocks using the aforementioned plasma cutting machine, etc., the cutting machine must be moved in multiple directions, which can make remote operation difficult and can require large equipment. When breaking down concrete into blocks, the concrete cannot be cut into small pieces, which creates the problem that concrete with high and low levels of activation cannot be cut separately.

The current situation is that the disposal costs of highly activated concrete are higher than those of low activated concrete. Therefore, if highly activated concrete cannot be cut separately from low activated concrete as described above, the disposal costs of the concrete could become high.

Furthermore, when dismantling concrete into blocks, the pieces of dismantled concrete tend to be relatively large, making it difficult to store them in waste containers. In addition, the cutting machine that cuts the radioactive concrete into blocks itself becomes secondary waste, resulting in a large amount of secondary waste.

The present disclosure aims to provide a demolition and removal method and demolition and removal device that can be easily operated remotely, reduces the cost of disposing of concrete, and allows for easy storage of demolished concrete.

The demolition and removal method according to the present disclosure is a method for demolition and removal of highly radioactive concrete, comprising: a step of chipping the concrete by spraying high-pressure liquefied gas onto the surface while a high-pressure liquefied gas spraying device moves along the surface of the concrete; and a step of recovering the concrete chipped in the chipping step, in which the chipping step crushes the concrete into powder and granular material by spraying high-pressure liquefied gas, and in the recovering step, the concrete that has been crushed as powder and granular material is recovered and the surface of the concrete is covered with a hood portion of the high-pressure liquefied gas spraying device, and in the chipping step, In the process, high-pressure liquefied gas is sprayed onto the surface of the concrete covered by the hood portion to chip the concrete, and in the recovery process, the concrete that is covered by the hood portion and has been crushed into powder is recovered, and the hood portion has a sloping portion that extends diagonally downward as it moves away from the surface of the concrete, and in the recovery process, the concrete that has been crushed into powder in the chipping process accumulates on the sloping portion and the chipped concrete is recovered by a recovery mechanism in the internal space of the hood portion, and the concrete powder that was not completely recovered by the recovery mechanism accumulates in the sloping portion .

In this demolition and removal method, the high-pressure liquefied gas injection device moves along the surface of the highly activated concrete and injects high-pressure liquefied gas onto the surface to chip the concrete. Therefore, the concrete can be chipped by the injection of high-pressure liquefied gas by the high-pressure liquefied gas injection device, and the high-pressure liquefied gas injection device can be easily operated remotely. In this demolition and removal method, in the chipping process, the concrete is crushed into powder by the injection of high-pressure liquefied gas. Therefore, the concrete can be finely crushed into powder by the injection of high-pressure liquefied gas, and concrete with a high activation level can be selectively chipped. Therefore, concrete with a high activation level can be chipped separately from concrete with a low activation level, and the mixing of low activation level concrete with high activation level concrete can be suppressed, and the disposal cost of concrete can be reduced. In addition, by crushing the concrete into powder, the crushed concrete can be easily stored in a waste storage container. Furthermore, the injected high-pressure liquefied gas is vaporized when chipping the concrete, so it does not become secondary waste. This reduces the amount of secondary waste.

However , when cutting concrete into blocks as described above, activated concrete dust scatters during cutting, which can cause a problem of difficulty in collecting the activated dust. In contrast, in the above-mentioned demolition and removal method, the concrete is chipped while the surface of the concrete is covered with the hood of the high-pressure liquefied gas injection device, and the concrete powder covered by the hood is collected. Therefore, the concrete can be crushed and collected inside the hood, so that the chipped concrete can be easily collected.

Since the powder particles of the chipped concrete are accumulated on the inclined portion of the hood portion, the chipped concrete can be collected more easily.

The above-mentioned demolition and removal method may include a step of sucking up the concrete collected in the collecting step, and a step of storing the concrete sucked up in the sucking step in a waste container. In this case, the collected concrete is sucked up and stored in the waste container, making it even easier to suck up and store the concrete powder.

The high-pressure liquefied gas may be high-pressure liquid nitrogen, and in the chipping process, the high-pressure liquid nitrogen may be sprayed onto the surface to chip the concrete. In this case, high-pressure liquid nitrogen is non-flammable, so the high-pressure liquefied gas can be easily handled. Furthermore, high-pressure liquid nitrogen has a high vaporization power, and can increase the jet efficiency when sprayed onto the surface of the concrete, so that the concrete can be efficiently chipped.

The concrete contains a highly activated area located on the surface side of the concrete and having a certain amount of radiation or more, and a low activated area located on the opposite side of the surface of the highly activated area and having a radiation amount less than a certain amount, and in the chipping process, only the highly activated area of the concrete may be selectively chipped. In this case, since only the highly activated area located on the surface side of the concrete is selectively chipped in the chipping process, the highly activated area with a high activation level can be chipped separately from the low activated area. Therefore, since only the highly activated area can be selectively chipped and disposed of in a different way from the low activated area, the cost of disposing of the concrete can be reduced.

The demolition and removal equipment according to the present disclosure is a demolition and removal equipment for dismantling and removing highly radioactive concrete, and is provided with a high-pressure liquefied gas injection device that moves along the surface of the concrete, the high-pressure liquefied gas injection device chips the concrete by injecting high-pressure liquefied gas onto the surface as it moves along the surface to crush the concrete into powder and granular material , the surface of the concrete is covered with a hood portion of the high-pressure liquefied gas injection device, the high-pressure liquefied gas injection device chips the concrete by injecting high-pressure liquefied gas onto the surface of the concrete covered by the hood portion, and the concrete that is covered by the hood portion and has been crushed into powder and granular material is recovered, the hood portion has a slope that extends diagonally downward as it moves away from the surface of the concrete, and during recovery, the concrete that has been crushed into powder and granular material accumulates on the slope, the chipped concrete is recovered by a recovery mechanism in the internal space of the hood portion, and the powder and granular material of the concrete that was not completely recovered by the recovery mechanism accumulates on the slope portion .

In this demolition and removal device, the high-pressure liquefied gas spraying device moves along the surface of the highly activated concrete while spraying high-pressure liquefied gas to chip the concrete, so that the high-pressure liquefied gas spraying device can be easily remotely operated, as in the demolition and removal method described above. In this demolition and removal device, the concrete is crushed into powder by spraying high-pressure liquefied gas onto the concrete, so that concrete with a high activation level can be selectively chipped. Therefore, the mixing of low-activation concrete with high-activation concrete can be suppressed, so that the cost of disposing of concrete can be reduced. Furthermore, by crushing the concrete into powder, the activated concrete can be easily stored in a waste storage container. And, the sprayed high-pressure liquefied gas vaporizes when chipping the concrete, so it does not become secondary waste. As a result, the amount of secondary waste can be reduced.

The present disclosure allows for easy remote operation, reduces the cost of disposing of concrete, and makes it easy to store demolished concrete.

1 is a cross-sectional view showing an exemplary nuclear reactor to which a dismantling and removal method and a dismantling and removal apparatus according to an embodiment are applied. FIG. 2 is a perspective view showing a schematic diagram of the nuclear reactor of FIG. 1. 1 is a perspective view showing a high-pressure liquefied gas injection device according to an embodiment. FIG. FIG. 4 is a perspective view of the high-pressure liquefied gas ejection device according to the embodiment, seen from a different direction than that shown in FIG. 3 . FIG. 2 is a side view of the high-pressure liquefied gas injection device according to the embodiment. 1 is a diagram showing a schematic diagram of high-pressure liquefied gas being sprayed by a high-pressure liquefied gas spraying device according to an embodiment. FIG. 4A, 4B, and 4C are cross-sectional views showing a state in which the injected high-pressure liquefied gas is crushing the concrete. FIG. 2 is a diagram showing a schematic diagram of the state of concrete that has been crushed into granular powder. 1 is a flowchart illustrating an example of steps of a dismantling and removal method according to an embodiment.

Below, an embodiment of the dismantling and removal method and dismantling and removal device according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In addition, the drawings may be partially simplified or exaggerated to facilitate understanding, and the dimensional ratios, etc. are not limited to those shown in the drawings.

Figure 1 shows a nuclear reactor N made of concrete C to which the dismantling and removal method and dismantling and removal device according to the embodiment are applied. The nuclear reactor N is, for example, a research reactor, and the nuclear reactor N is equipped with a biological shield 2, which includes concrete C and reinforcing bars.

The reactor N is, for example, a vertically long cylinder having a vertical hole N1 in which the pressure vessel 3 is placed. As an example, the reactor N is a pressurized water reactor (PWR). Inside the pressure vessel 3, there are provided a number of fuel assemblies each made up of a bundle of fuel rods that cause a nuclear fission reaction to generate thermal energy, and the heat generation is controlled by controlling the nuclear fission reaction with a control rod inserted between the fuel assemblies.

For example, a steel plate lining is applied along the inner surface of the vertical hole N1 of the reactor N. In this embodiment, for example, the lining is peeled off and the concrete C in the high-dose area in the primary shielding wall of the reactor N is dismantled. The activation levels inside the reactor N are classified into marginal depth waste (L1), pit disposal waste (L2), trench disposal waste (L3), clearance (CL), and non-radioactive waste (NR). L1 is the highest activation level, L2 is the second highest, L3 is the third highest, CL is the fourth highest, and NR is the lowest.

The disposal methods differ for L1 radioactive waste, L2 radioactive waste, L3 radioactive waste, CL radioactive waste, and NR non-radioactive waste. CL does not need to be treated as radioactive waste, but L3 requires trench disposal by burying it in the shallow ground, L2 requires pit disposal, and L1 requires subsurface disposal.

The disposal costs for L1 subsurface disposal tend to be higher than those for L2 pit disposal, which tend to be higher than those for L3 trench disposal. As such, the higher the activation level of the waste, such as concrete C, the higher the disposal costs, so it is necessary to selectively remove only the parts with high activation levels. In this embodiment, for example, it is possible to selectively remove only the concrete C at L1 and only the concrete C at L2.

For example, concrete C includes a high activation area A1 that has a certain amount of radiation or more and constitutes the surface C1 of concrete C, and a low activation area A2 that has an amount of activation less than a certain amount and is located on the opposite side of the surface C1 of high activation area A1. Furthermore, in this embodiment, high activation area A1 includes a first area A11 and a second area A12 that has a lower activation level than the first area A11, and low activation area A2 includes a third area A21 and a fourth area A22 that has a lower activation level than the third area A21. As an example, the first area A11 corresponds to concrete C with L1, the second area A12 corresponds to concrete C with L2, the third area A21 corresponds to concrete C with L3, and the fourth area A22 corresponds to concrete C with CL.

The distribution of activation levels of concrete C, such as the first area A11, second area A12, third area A21, and fourth area A22, is, for example, known in advance. The method for determining the distribution of activation levels may involve calculating the activation levels of each part of concrete C by activation calculation, or may involve core analysis in which a part of concrete C is extracted and analyzed. In this embodiment, with the distribution of activation levels of concrete C known in advance, the concrete C is selectively chipped off in areas with high activation levels.

As shown in Figures 1 and 2, the dismantling and removal device 1 according to this embodiment is capable of selectively chipping away highly activated portions of the concrete C, and is provided in a position facing the surface C1 of the concrete C. For example, the dismantling and removal device 1 includes a work manipulator 5 provided in the vertical hole N1 of the reactor N, and a high-pressure liquefied gas injection device 10 facing the surface C1 of the concrete C.

As shown in FIG. 2, the work manipulator 5 is attached to a wire 5b extending in the vertical direction D1. For example, the work manipulator 5 has a cutting device 5c including a cutter and a laser suspended from the wire 5b, and a support mechanism 5d that is disposed on the upper surface C2 of the concrete C and supports the cutting device 5c and the high-pressure liquefied gas spraying device 10 from the upper surface C2 via the wire 5b. The high-pressure liquefied gas spraying device 10 is provided, for example, below the cutting device 5c.

The cutting device 5c has, for example, multiple arms 5k with cutters or lasers attached to their tips. As one example, the multiple arms 5k may be arranged in a line in the circumferential direction of the cylindrical surface C1. As one example, the support mechanism 5d includes a plate-like member 5f that is placed on the upper surface C2, and a tubular member 5g that is placed on the plate-like member 5f.

The cylindrical member 5g has a pair of upper and lower annular portions 5h, and a number of pillar portions 5j that connect the pair of annular portions 5h to each other. For example, equipment for demolishing concrete C is placed in the space formed between the multiple pillar portions 5j. Although an example of the work manipulator 5 has been described above, the configuration of the work manipulator 5 is not limited to the above example and can be modified as appropriate.

The demolition and removal device 1 may, for example, include a connection member 6 extending from the high-pressure liquefied gas injection device 10, and a tank 7 provided on the upper surface C2 of the concrete C via the connection member 6. The tank 7 is connected to the high-pressure liquefied gas injection device 10 via the connection member 6. The tank 7 is a tank that supplies high-pressure liquefied gas G (see FIG. 6) to the high-pressure liquefied gas injection device 10, and the connection member 6 includes a supply path for high-pressure liquefied gas to the high-pressure liquefied gas injection device 10, and a recovery path for the concrete C through which the concrete C demolished by the high-pressure liquefied gas injection device 10 passes.

The demolition and removal device 1 may include, for example, a pump 8 and a dust collector 9 connected to the connection member 6 on the upper surface C2. The pump 8 supplies high-pressure liquefied gas G stored in the tank 7 to the high-pressure liquefied gas injection device 10 via the connection member 6. The dust collector 9 collects the demolished concrete C from the high-pressure liquefied gas injection device 10 via the connection member 6. The dust collector 9 collects, for example, the concrete C that has been demolished by the high-pressure liquefied gas injection device 10 and turned into powder P (see Figures 7(b), 7(c) and 8).

The high-pressure liquefied gas spraying device 10 (hood section 11 described later) is movable along the surface C1 of the concrete C, and as it moves, it sprays high-pressure liquefied gas G onto the surface C1 to chip the concrete C. The high-pressure liquefied gas spraying device 10 is movably supported, for example, by a wire 5b. The high-pressure liquefied gas spraying device 10 is movable, for example, in both the vertical and horizontal directions.

For example, the high-pressure liquefied gas injection device 10 is remotely operated (remotely monitored) from outside the reactor N and moves to inject high-pressure liquefied gas G onto the concrete C. The high-pressure liquefied gas injection device 10 may also move automatically along the surface C1, which contributes to reducing the labor required for chipping the concrete C.

Figure 3 is a perspective view showing the high-pressure liquefied gas injection device 10. Figure 4 is a perspective view of the high-pressure liquefied gas injection device 10 seen from a different direction than that of Figure 3. As shown in Figures 3 and 4, the high-pressure liquefied gas injection device 10 comprises a hood portion 11 that covers the surface C1 of the concrete C, an injection mechanism 12 that is disposed in the internal space 11j of the hood portion 11 and injects high-pressure liquefied gas G onto the surface C1 of the concrete C, and a recovery mechanism 13 that recovers the chipped concrete C.

The hood portion 11 has, for example, a rectangular box shape. The length L1 of the hood portion 11 in the vertical direction D1, the length L2 of the hood portion 11 in the first direction D2, and the length L3 of the hood portion 11 in the second direction D3 are, for example, 1500 mm or less. The first direction D2 is a direction that intersects (for example, perpendicular to) the vertical direction D1, and the second direction D3 is a direction that intersects (for example, perpendicular to) both the vertical direction D1 and the first direction D2.

As an example, the first direction D2 is the width direction of the hood portion 11, and the second direction D3 is the depth direction of the hood portion 11. In addition, the first direction D2 may be a direction along the surface C1 of the concrete C, and the second direction D3 may be a direction intersecting (e.g., perpendicular to) the surface C1 of the concrete C.

The injection mechanism 12 injects high-pressure liquefied gas G into the portion of the concrete C covered by the hood portion 11 to chip the concrete C. The concrete C chipped by the injection mechanism 12 is collected by the collection mechanism 13 in the internal space 11j of the hood portion 11. For example, the hood portion 11 has a top surface portion 11b facing upward in the vertical direction D1, a pair of side portions 11c facing in the first direction D2, a back surface portion 11d facing the opposite side of the surface C1 (the depth direction of the hood portion 11), an opening portion 11f that is in contact with the surface C1, and a bottom surface portion 11g facing the opposite side of the top surface portion 11b. In the following description, the direction in which the opening portion 11f of the hood portion 11 is provided may be referred to as the "front" and the direction in which the back surface portion 11d of the hood portion 11 is provided may be referred to as the "rear". However, these directions are for convenience of description and do not limit the arrangement position of objects, etc.

The top surface portion 11b is, for example, flat and extends in both the first direction D2 and the second direction D3. Each of the pair of side surface portions 11c is flat and extends in both the vertical direction D1 and the second direction D3, and for example, the back surface portion 11d is flat and extends in both the vertical direction D1 and the first direction D2. As an example, in the hood portion 11 having six surfaces, five of the six surfaces are closed except for the opening 11f.

Figure 5 is a side view of the high-pressure liquefied gas spray device 10 viewed along the first direction D2. As shown in Figures 3 to 5, the high-pressure liquefied gas spray device 10 has an inclined portion 14. The inclined portion 14 is formed on the bottom surface portion 11g of the hood portion 11 and extends diagonally downward as it moves away from the opening 11f.

In the internal space 11j of the hood section 11, high-pressure liquefied gas G is sprayed by the spray mechanism 12 to recover the chipped concrete C. For example, concrete C powder P (see Figures 7(b), 7(c) and 8) that could not be fully recovered by the recovery mechanism 13 accumulates in the inclined section 14 (inside the inclined section 14). In this way, by providing the hood section 11 with the inclined section 14 that extends diagonally downward as it moves away from the opening 11f, it is possible to prevent the chipped concrete C from leaking outside the hood section 11.

The hood portion 11 includes, for example, a plurality of spring portions 15 that constitute the opening 11f. The material of the spring portions 15 includes, for example, at least one of nylon and rubber. The plurality of spring portions 15 are arranged around the entire circumference of the opening 11f. In other words, the plurality of spring portions 15 are arranged so as to be aligned along the opening 11f. The plurality of spring portions 15 are arranged so as to be aligned along the vertical direction D1, and are also arranged so as to be aligned along the first direction D2.

The spring portion 15 has, for example, a first plate portion 15b that forms the opening 11f, a second plate portion 15c that is located on the rear side of the first plate portion 15b, a spring 15d that expands and contracts in the second direction D3 above the second plate portion 15c, and a support plate 15f that extends upward relative to the second plate portion 15c and supports the spring 15d so that it can expand and contract.

As an example, the end faces facing the front side of the first plate portion 15b are aligned along the vertical direction D1 and the first direction D2, thereby forming the opening 11f. The spring portion 15 includes, for example, a plurality of springs 15d and a plurality of support plates 15f. Although an example of the configuration of the spring portion 15 has been described above, the configuration of the spring portion 15 is not limited to the above example.

Each spring portion 15 (spring 15d) is expandable and contractable along the second direction D3. When no external force is applied to the opening 11f, the opening 11f has a rectangular shape as shown in FIG. 3. However, when a rearward external force is applied to the opening 11f, the spring portion 15 in the portion to which the external force is applied moves rearward, causing the opening 11f to deform.

In this way, because each of the multiple spring portions 15 is movable rearward, even if the opening 11f is brought into contact with an uneven portion of the surface C1, the opening 11f can be made to follow the shape of the uneven portion. As a result, even if the opening 11f is brought into contact with the uneven portion, the opening 11f can follow the shape of the uneven portion, so that the surface C1 can be more reliably sealed and the powder P of the chipped concrete C can be more reliably prevented from leaking outside the hood portion 11.

3 and 4, the injection mechanism 12 has, for example, a rectangular box-shaped injection unit 17 that injects high-pressure liquefied gas G, and a movement mechanism 12c that moves the injection unit 17 in the internal space 11j of the hood unit 11. The movement mechanism 12c has, for example, a support member 12d that supports the injection unit 17, a first rail portion 12f that supports the support member 12d so that it can move along the first direction D2, and a second rail portion 12g that supports the first rail portion 12f so that it can move along the vertical direction D1.

The second rail portion 12g is fixed in the internal space 11j of the hood portion 11. By moving the first rail portion 12f along the vertical direction D1 relative to the second rail portion 12g and moving the support member 12d along the first direction D2 relative to the first rail portion 12f, it is possible to face the injection portion 17 to any part of the opening 11f.

The recovery mechanism 13 recovers the concrete C granulated by the injection mechanism 12 injecting high-pressure liquefied gas G onto the surface C1 of the concrete C. The recovery mechanism 13 has a first tubular portion 13b that communicates with the internal space 12h of the injection unit 17, and a second tubular portion 13c that extends outward from the side portion 11c of the hood portion 11.

The first tubular portion 13b extends from the injection mechanism 12 and penetrates the side portion 11c to the outside of the hood portion 11. The recovery mechanism 13 has a third tubular portion 13d that joins the first tubular portion 13b and the second tubular portion 13c outside the hood portion 11. One end of the first tubular portion 13b communicates with the internal space 12h of the injection portion 17, and one end of the second tubular portion 13c communicates with the internal space 11j of the hood portion 11.

The recovery mechanism 13 further includes, for example, an exhaust fan (not shown) provided on the opposite side of the third tubular portion 13d from the hood portion 11. This exhaust fan sucks in both the powder P in the internal space 11j of the hood portion 11 and the powder P in the internal space 12h of the injection portion 17. That is, by operating the exhaust fan, the powder P in the internal space 11j is sucked into the third tubular portion 13d via the second tubular portion 13c, and the powder P in the internal space 12h is sucked into the third tubular portion 13d via the first tubular portion 13b. The powder P sucked into the third tubular portion 13d is collected in the dust collector 9, for example, via the connecting member 6 described above.

The high-pressure liquefied gas injection device 10 has a hood section 11 and an injection section 17 disposed inside the hood section 11, forming a double structure for suction of powdered or granular material P. That is, the powdered or granular material P in the internal space 12h of the injection section 17 is sucked into the first tubular section 13b and discharged to the outside of the injection section 17 and the hood section 11.

The powder P that could not be sucked through the first tubular portion 13b is sucked into the second tubular portion 13c and discharged to the outside of the hood portion 11. Furthermore, the powder P that could not be sucked through the second tubular portion 13c is accumulated in the inclined portion 14. Therefore, the high-pressure liquefied gas injection device 10 has a triple structure (a triple structure of the first tubular portion 13b, the second tubular portion 13c, and the inclined portion 14) for recovering the powder P of the concrete C. Therefore, leakage of the concrete C that has become the powder P from the hood portion 11 is suppressed, and the powder P can be recovered more reliably.

Next, the detailed structure of the ejection unit 17 will be described with reference to FIG. 6. FIG. 6 is an enlarged perspective view of the ejection unit 17 of the ejection mechanism 12. For example, the ejection unit 17 has a top surface portion 17b facing upward in the vertical direction D1, a pair of side surfaces 17c facing the first direction D2, an opening portion 17f facing the surface C1, and a bottom surface portion 17g facing the opposite side of the top surface portion 17b.

As an example, the spray portion 17 has six faces, and five of the six faces are blocked except for the opening 17f. The inside of the opening 17f is recessed toward the rear, and an opening 17j is formed in this recessed portion. As an example, the opening 17j has a circular shape. A nozzle 17h that sprays high-pressure liquefied gas G is disposed inside the opening 17j.

The ejection portion 17 may, for example, include a plurality of spring portions 18 that form the opening 17f. Each of the plurality of spring portions 18 is disposed around the entire circumference of the opening 17f. That is, the plurality of spring portions 18 are disposed so as to be aligned along the opening 17f. The plurality of spring portions 18 are disposed so as to be aligned along the vertical direction D1, and are also disposed so as to be aligned along the first direction D2.

The configuration of the spring portion 18 can be the same as that of the spring portion 15 described above, for example. However, because the size of the spring portion 18 is smaller than that of the spring portion 15, for example, the illustration of the spring portion 18 is simplified. Each spring portion 18 is capable of expanding and contracting along the second direction D3. When no external force is applied to the opening 17f, the opening 17f has a rectangular shape.

However, when a rearward external force is applied to the opening 17f, the spring portion 18 in the portion to which the external force is applied moves rearward, causing the opening 17f to deform. Therefore, similar to the spring portion 15 described above, by allowing the multiple spring portions 18 to move rearward, the opening 17f can be made to conform to the unevenness of the surface C1 of the concrete C.

As a result, in the injection section 17, similar to the hood section 11, the surface C1 is reliably sealed to prevent the powder P of the chipped concrete C from leaking outside the injection section 17. The nozzle 17h of the injection section 17 has an injection hole 17k through which the high-pressure liquefied gas G is injected.

The high-pressure liquefied gas G is, for example, high-pressure liquid nitrogen with a liquefaction point (boiling point) of -196°C. In this case, the high-pressure liquefied gas G is nitrogen gas that has been liquefied through a refrigeration cycle, and expands approximately 600 to 700 times when vaporizing. In this embodiment, the concrete C that has been activated by the energy generated when the high-pressure liquefied gas G vaporizes is selectively chipped.

Figures 7(a), 7(b) and 7(c) are longitudinal cross-sectional views of concrete C, which show the state in which high-pressure liquefied gas G is sprayed onto concrete C and chipped. As shown in Figures 6 and 7(a), when high-pressure liquefied gas G is sprayed onto surface C1 of concrete C from spray unit 17, the sprayed high-pressure liquefied gas G vaporizes and expands on surface C1.

As shown in Figures 7(b) and 7(c), when high-pressure liquefied gas G vaporizes and expands on the surface C1 of concrete C, the concrete C on the surface C1 is crushed by the explosive energy generated by the vaporization and expansion. As shown in Figures 7(c) and 8, the crushed concrete C becomes powder P.

Figure 8 shows concrete C that has been chipped into powdered or granular material P. In this disclosure, "powdered or granular material" refers to powder and granular material (particulate material), and includes, for example, concrete that has been crushed into powder or granular material. The diameter of the powdered or granular material P is, for example, several μm or more and 30 mm or less. In addition, the chipping range (width of the concrete C to be chipped) W by the injection of high-pressure liquefied gas G from the injection unit 17 is, for example, 3 cm or more and 7 cm or less (approximately 5 cm as an example). Therefore, the powdered or granular material P can be easily collected by the hood unit 11 and the collection mechanism 13.

Next, an example of the dismantling and removal method according to this embodiment will be described with reference to the flowchart in FIG. 9. FIG. 9 shows an example of the steps of the dismantling method for dismantling the concrete C of the reactor N illustrated in FIG. 1 and FIG. 2. First, a high-pressure liquefied gas injection device 10 is lowered into the vertical hole N1 of the reactor N via a connection member 6 (or wire 5b), and a laser and cutter are attached to a work manipulator 5, which is then lowered into the vertical hole N1 via the wire 5b.

First, the lining of the vertical hole N1 of the reactor N is cut and peeled off by the laser of the work manipulator 5 (step S1). Next, as shown in FIG. 7(a), the demolition and removal device 1 moves the high-pressure liquefied gas injection device 10 to the location where the concrete C to be chipped is present, and covers and seals the surface C1 of the concrete C at that location (covering process, step S2). At this time, the opening 11f of the hood portion 11 is pressed against the surface C1 of the concrete C to seal the surface C1 of the concrete C.

With the surface C1 of the concrete C sealed, the injection unit 17 injects high-pressure liquefied gas G onto the surface C1 of the concrete C to chip the concrete C (chipping process, step S3). As shown in Figures 7(b) and 7(c), the concrete C at the location where the high-pressure liquefied gas G was injected is crushed into powder P, and the powder P is collected (collection process).

Then, the powder P collected inside the hood portion 11 is sucked in (suction process, step S4). Specifically, the powder P in the internal space 12h of the injection portion 17 is sucked in through the first tubular portion 13b and the third tubular portion 13d, and the powder P in the internal space 11j of the hood portion 11 is sucked in through the second tubular portion 13c and the third tubular portion 13d. The powder P that was not sucked in is accumulated in the inclined portion 14.

As described above, the concrete C is chipped by spraying the high-pressure liquefied gas G, and the reinforcing bars inside the concrete C are cut by the cutter of the work manipulator 5 (step S5). Meanwhile, the powder P sucked in in the above process is stored in a waste storage container (storing process, step S6). The powder P stored in the waste storage container is then removed from the reactor N (step S7), completing the series of processes.

Next, the effects obtained from the demolition and removal method and demolition and removal device 1 according to this embodiment will be described. In the demolition and removal method and demolition and removal device 1 according to this embodiment, the high-pressure liquefied gas injection device 10 moves along the surface C1 of the highly radioactive concrete C while injecting high-pressure liquefied gas G onto the surface C1 to chip the concrete C. Therefore, since the concrete C can be chipped by the injection of high-pressure liquefied gas G by the high-pressure liquefied gas injection device 10, the high-pressure liquefied gas injection device 10 can be easily operated remotely.

In the dismantling and removal method and dismantling and removal device 1 of this embodiment, in the chipping process, the concrete C is crushed into powder P by the injection of high-pressure liquefied gas G. Therefore, since the concrete C can be finely crushed into powder P by the injection of high-pressure liquefied gas G, it is possible to selectively chip concrete C with a high activation level (for example, only concrete C with L1 or only concrete C with L2).

As a result, a process can be carried out in which concrete C with a high activation level is separated from concrete C with a low activation level and chipped, thereby preventing the mixing of concrete C with a high activation level with concrete C with a low activation level, thereby reducing the disposal costs of concrete C.

In addition, by crushing the concrete C into powder P, the crushed concrete C can be easily stored in a waste storage container. Furthermore, the sprayed high-pressure liquefied gas G vaporizes when the concrete C is chipped, so it does not become secondary waste. Therefore, the amount of secondary waste can be reduced.

The demolition and removal method and demolition and removal device 1 according to this embodiment may include a step of covering the surface C1 of the concrete C with the hood portion 11 of the high-pressure liquefied gas injection device 10, and in the chipping step, high-pressure liquefied gas G may be injected onto the surface C1 of the concrete C covered by the hood portion 11 to chip the concrete C, and in the recovery step, the concrete C that is covered by the hood portion 11 and crushed into powder P may be recovered.

However, when cutting concrete into blocks as has been done conventionally, activated concrete dust scatters during cutting, which can cause the problem of making it difficult to collect the activated dust. In contrast, in the demolition and removal method and demolition and removal device 1 of this embodiment, the concrete C is chipped while the surface C1 of the concrete C is covered with the hood portion 11 of the high-pressure liquefied gas injection device 10, and the powder P of the concrete C covered by the hood portion 11 is collected. Therefore, the concrete C can be crushed and collected in the internal space 11j of the hood portion 11, making it easy to collect the chipped concrete C.

As shown in Figures 7(a), 7(b) and 7(c), the hood portion 11 may have an inclined portion 14 that extends diagonally downward as it moves away from the surface C1 of the concrete C, and in the recovery process, the concrete C that has been crushed as powder P in the chipping process may accumulate in the inclined portion 14. In this case, the powder P of the chipped concrete C accumulates in the inclined portion 14 of the hood portion 11, making it even easier to recover the chipped concrete C.

The demolition and removal method and demolition and removal device 1 according to this embodiment may include a step of sucking up the concrete C recovered in the recovery step, and a step of storing the concrete C sucked up in the suction step in a waste container. In this case, the recovered concrete C is sucked up and stored in the waste container, so that the powder P of the concrete C can be sucked up and stored in the waste storage container more easily.

As mentioned above, the high-pressure liquefied gas G may be high-pressure liquid nitrogen, and in the chipping process, the high-pressure liquid nitrogen may be sprayed onto the surface C1 to chip the concrete C. In this case, since the high-pressure liquid nitrogen is non-flammable, the high-pressure liquefied gas G can be easily handled. Furthermore, since the high-pressure liquid nitrogen has a high vaporization power and can increase the jet efficiency when sprayed onto the surface C1 of the concrete C, the concrete C can be efficiently chipped.

As shown in FIG. 1, concrete C includes a highly activated area A1 that has a certain amount of radiation or more and is located on the surface C1 side of concrete C, and a low activated area A2 that has a certain amount of radiation or less and is located on the opposite side of surface C1 of highly activated area A1. In the chipping process, only highly activated area A1 of concrete C may be selectively chipped. In this case, since only highly activated area A1 located on the surface C1 side of concrete C is selectively chipped in the chipping process, highly activated area A1, which has a high activation level, can be chipped separately from low activated area A2. Therefore, since only highly activated area A1 can be selectively chipped and disposed of in a different manner from low activated area A2, the disposal cost of concrete C can be reduced.

The above describes the embodiments of the dismantling and removal method and dismantling and removal device according to the present disclosure. However, the present disclosure is not limited to the above-mentioned embodiments. Various modifications of the present disclosure are possible without changing the gist of the claims. In other words, the configuration, shape, size, material, number and arrangement of each part of the dismantling and removal device, as well as the content and order of each step of the dismantling and removal method, can be modified as appropriate without changing the gist of the above.

In the above embodiment, a high-pressure liquefied gas spraying device 10 is described that includes a hood portion 11 having a rectangular opening 11f. However, the shape of the opening of the hood portion of the high-pressure liquefied gas spraying device is not limited to a rectangular shape and can be changed as appropriate. For example, it may be curved in an arc shape to fit the surface of curved concrete.

Furthermore, the high-pressure liquefied gas spraying device according to the present disclosure may be a high-pressure liquefied gas spraying device that does not have a hood portion. Also, in the above-described embodiment, the spring portion 15 including at least one of nylon and rubber was described. However, the material of the spring portion that constitutes the opening of the hood portion is not limited to nylon or rubber, and can be changed as appropriate.

In the above embodiment, the distribution of the activation level of the concrete C is known in advance, and an example has been described in which concrete C with a previously known high activation level is chipped off. However, for example, a detection rod attached to the work manipulator 5 may measure the activation level of the concrete C and selectively chip off the concrete C with a high activation level. In this way, the timing of measuring the activation level of the concrete C is not particularly limited. Also, for example, information on the activation level and activated area of the concrete C may be constructed in advance by BIM (Building Information Management), and the high-pressure liquefied gas injection device 10 may be automatically operated by linking the data constructed in the BIM with the demolition and removal device 1. In this case, chipping off of the concrete C can be fully automated.

In the above embodiment, an example was described in which the high-pressure liquefied gas G was high-pressure liquefied nitrogen. However, the high-pressure liquefied gas may be something other than liquefied nitrogen. For example, the high-pressure liquefied gas may be high-pressure liquefied air or high-pressure liquefied oxygen. The liquefaction point (boiling point) of oxygen is -183°C, which is higher than that of nitrogen, and therefore has the advantage of being easier to handle.

In the above embodiment, an example of chipping concrete C of a reactor N, which is a pressurized water reactor (PWR), has been described. Since a PWR has many highly activated areas, the dismantling and removal method and dismantling and removal device 1 according to the above embodiment may be particularly effective. However, the subject to which the dismantling and removal method and dismantling and removal device according to the present disclosure are applied is not limited to PWRs and is not particularly limited. For example, the dismantling and removal method and dismantling and removal device according to the present disclosure may be applied to a boiling water reactor (BWR) or to a structure other than a reactor.

1 ... Dismantling and removal device, 2 ... Living body shield, 3 ... Pressure vessel, 5 ... Working manipulator, 5b ... Wire, 5c ... Cutting device, 5d ... Support mechanism, 5f ... Plate-shaped member, 5g ... Cylindrical member, 5h ... Ring-shaped portion, 5j ... Column portion, 5k ... Arm, 6 ... Connection member, 7 ... Tank, 8 ... Pump, 9 ... Dust collector, 10 ... High-pressure liquefied gas injection device, 11 ... Hood portion, 11b ... Top surface portion, 11c ... Side portion, 11d ... Back portion, 11f ... Opening portion, 11g ... Bottom portion, 11j ... Internal space, 12 ... Injection mechanism, 12c ... Moving mechanism, 12d ... Support member, 12f ... First rail portion, 12g ... Second rail portion, 12h ... Internal space, 13 ... Recovery mechanism, 13b ... First tubular portion, 1 ３ｃ…第２管状部、１３ｄ…第３管状部、１４…傾斜部、１５…バネ部、１５ｂ…第１板部、１５ｃ…第２板部、１５ｄ…バネ、１５ｆ…支持板、１７…噴射部、１７ｂ…天面部、１７ｃ…側面部、１７ｆ…開口部、１７ｇ…底面部、１７ｈ…ノズル、１７ｊ…開口、１７ｋ…噴射孔、１８…バネ部、Ａ１…高放射化領域、Ａ２…低放射化領域、Ａ１１…第１領域、Ａ１２…第２領域、Ａ２１…第３領域、Ａ２２…第４領域、Ｃ…コンクリート、Ｃ１…表面、Ｃ２…上面、Ｄ１…鉛直方向、Ｄ２…第１方向、Ｄ３…第２方向、Ｇ…高圧液化ガス、Ｎ…原子炉、Ｎ１…縦穴、Ｐ…粉粒体、Ｗ…範囲。

Claims (5)

A method for dismantling and removing highly radioactive concrete, comprising the steps of:
a step of moving a high-pressure liquefied gas spraying device along the surface of the concrete and spraying high-pressure liquefied gas onto the surface to chip the concrete;
A step of recovering the concrete chipped in the chipping step;
Equipped with
In the crushing step, the high-pressure liquefied gas is sprayed to crush the concrete into powder particles,
In the recovering step, the concrete crushed as the powder or granular material is recovered,
covering the surface of the concrete with a hood portion of the high-pressure liquefied gas injection device;
In the chipping step, high-pressure liquefied gas is sprayed onto the surface of the concrete covered by the hood portion to chip the concrete,
In the recovering step, the concrete that is covered by the hood portion and crushed into the powder or granular material is recovered,
The hood portion includes an inclined portion extending obliquely downward as it moves away from the surface of the concrete,
In the recovering step, the concrete crushed as the powder particles in the chipping step is accumulated on the inclined portion,
The chipped concrete is collected by a collection mechanism in the internal space of the hood portion,
The inclined portion accumulates the concrete powder that has not been completely collected by the collection mechanism.
Dismantling removal method. A step of suctioning the concrete recovered in the recovery step;
The concrete is then collected in a waste container.
The dismantling and removal method according to claim 1 . The high pressure liquefied gas is high pressure liquid nitrogen,
In the chipping step, the high-pressure liquid nitrogen is sprayed onto the surface to chip the concrete.
The dismantling and removal method according to claim 1 or 2 . the concrete includes a highly activated region having a radiation dose equal to or greater than a certain amount and located on the surface side of the concrete, and a low activation region having a radiation dose less than the certain amount and located on the opposite side of the surface of the highly activated region,
In the chipping step, only the highly activated area of the concrete is selectively chipped.
The dismantling and removal method according to any one of claims 1 to 3 . A demolition and removal device for dismantling and removing highly radioactive concrete,
a high-pressure liquefied gas jet device that moves along the surface of the concrete;
the high-pressure liquefied gas spraying device moves along the surface and sprays high-pressure liquefied gas onto the surface to break up the concrete into powder particles, thereby chipping the concrete;
Covering the surface of the concrete with a hood portion of the high-pressure liquefied gas injection device;
The high-pressure liquefied gas injection device injects high-pressure liquefied gas onto the surface of the concrete covered by the hood portion to chip the concrete,
The concrete that is covered with the hood portion and crushed into powder or granular material is collected,
The hood portion includes an inclined portion extending obliquely downward as it moves away from the surface of the concrete,
In the recovery, the concrete crushed as powder is accumulated on the inclined portion,
The chipped concrete is collected by a collection mechanism in the internal space of the hood portion,
The inclined portion accumulates the concrete powder that has not been completely collected by the collection mechanism.
Demolition removal equipment.

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