KR102631280B1 - Cutting device for decommissioning nuclear facilities and nuclear facilities decommissioning method using thereof - Google Patents

Abstract

The present invention relates to a cutting device for dismantling a nuclear facility and a method for dismantling a nuclear facility using the same. The cutting device for dismantling a nuclear facility according to the present invention mechanically removes the structure of the nuclear facility while moving along the structure of the nuclear facility. mechanical cutting means; a cutting auxiliary unit that moves together with the mechanical cutting means and selectively heats a position ahead of the movement path of the mechanical cutting means in the structure of a nuclear power facility; and a transfer unit that moves the mechanical cutting means and the cutting auxiliary unit together.
Accordingly, it is possible to quickly and safely proceed with the decommissioning of nuclear facilities.

Description

Cutting device for decommissioning nuclear facilities and nuclear facilities decommissioning method using the same}

The present invention relates to a cutting device for dismantling a nuclear facility and a method for dismantling a nuclear facility using the same. More specifically, it relates to a cutting device and method that enable the dismantling of a nuclear facility to be carried out quickly and safely.

Technologies applicable to cutting waste generated during the decommissioning of nuclear facilities are largely divided into thermal cutting technology and mechanical cutting technology.

Representative devices that implement dual thermal cutting technology include plasma torch, laser, oxy-propane flame, electric discharge machining (EDM), and metal decomposition machining (MDM). Methods such as Metal Disintegration Machining (CAMC), Contact Arc Metal Cutting (CAMC), and thermit lance are applied.

And devices that implement mechanical cutting technology generally include milling cutters, drills, disk saws, reciprocating saws, shears, grinders, Methods such as diamond wire cutting, water jet, and various pipe cutters can be used.

Most mechanical cutting devices have the advantage of generating less floating dust in the form of aerosol and not deteriorating performance even underwater, compared to thermal cutting technology, so they can be applied as a safe and eco-friendly cutting technology first when dismantling nuclear facilities.

On the other hand, all mechanical cutting devices have the characteristic that the cutting load, or reaction force, felt during the cutting process increases in proportion to the tensile strength of the object to be cut. Therefore, in order to cut high-strength waste such as metal structures, the mechanical cutting device must be made large and heavy in proportion to the strength of the object to be cut so that it can overcome the corresponding reaction force. However, the weight and size of the mechanical cutting device cannot be increased indefinitely due to limited work space and technical limitations, and accordingly, there are limits to the thickness and cutting speed that can be cut depending on the type of object.

In addition, when using mechanical cutting devices, not only is it impossible to avoid the generation of liquid secondary contaminants due to the use of cutting oil or coolant, but also the cutting efficiency is reduced due to frequent tool replacement and the tool can get caught in the object during cutting and get damaged. Process side effects, such as symptoms, are also serious.

On the other hand, thermal cutting devices do not have any part in direct contact with the metal, and as a result, no reaction force is generated due to the cutting load, so they can be made lighter in weight and relatively smaller in volume compared to mechanical cutting devices. In addition, it has the advantage of being able to quickly cut thick metal and high-rigidity materials.

However, as mentioned earlier, thermal cutting technology has the disadvantage that a large amount of floating dust and combustion gas is generated during the cutting process, which may increase the worker's radiation exposure, and thus requires additional facilities for dust removal and combustion gas treatment. Because of this, there are great difficulties in applying it to the cutting process of radioactive waste.

Meanwhile, among the radioactive waste generated during the dismantlement of nuclear facilities, high-strength structures used to directly encounter or shield radioactive materials and neutrons, such as the primary system of a nuclear power plant, contain radioactive materials on the inside or are contaminated by radioactivity on the inside by neutrons. Most of them.

In other words, a significant area between the outer surface and the inner surface is free of radioactive material or is non-radioactive, and performing mechanical cutting of the entire thick, high-strength structure due to the contaminated inner layer is economically inefficient due to the disadvantages mentioned above. There are bound to be technical limitations.

Accordingly, for safe and efficient decommissioning of nuclear facilities, the development of a method that can guarantee safety for the contaminated inner layer and increase cutting efficiency for areas excluding the contaminated inner layer is required.

KR 10-1845493 B1

Therefore, the purpose of the present invention is to solve such conventional problems, and is a cutting device for dismantling nuclear facilities that can quickly and safely dismantle nuclear facilities by applying different cutting methods depending on the depth of the nuclear facility structure. and a method of dismantling a nuclear facility using the same.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The above object is, according to the present invention, a cutting device for dismantling a nuclear facility, comprising: a mechanical cutting means for mechanically removing the structure of the nuclear facility while moving along the structure of the nuclear facility; a cutting auxiliary unit that moves together with the mechanical cutting means and selectively heats a position ahead of the movement path of the mechanical cutting means in the structure of a nuclear power facility; and a transfer unit that moves the mechanical cutting means and the cutting auxiliary unit together.

The mechanical cutting means may include an end mill or circular saw.

The end mill and the circular saw may be formed to be detachable.

The mechanical cutting means may be provided with an index to which the end mill and the circular saw are fixed.

The cutting assistant may be equipped with a plasma torch.

The cutting assistant may include a position control unit that rotates and moves the plasma torch based on the transfer unit.

The mechanical cutting means and the arc column generated from the plasma torch may be formed to be spaced apart from each other by a certain distance or more.

The cutting device for dismantling nuclear power facilities according to the present invention controls the mechanical cutting means, the cutting auxiliary unit, and the transfer unit, and a control unit that determines whether or not to operate the cutting auxiliary unit depending on the depth from the outer surface of the structure of the nuclear facility. It may further include.

The cutting device for dismantling nuclear power facilities according to the present invention further includes a temperature sensor that measures the temperature at a position ahead of the movement path of the mechanical cutting means in the structure of the nuclear power facility and transmits the measurement result to the control unit, wherein the control unit The operating speed of the transfer unit can be adjusted according to the measurement results of the temperature sensor.

The cutting device for dismantling a nuclear facility according to the present invention further includes a radiation dose measurement sensor that measures the radiation dose along the movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit, The control unit may determine whether to operate the cutting auxiliary unit according to the measurement result of the radiation dose measurement sensor.

According to another embodiment of the present invention, a mechanical cutting means for mechanically removing the structure of the nuclear facility while moving along the structure of the nuclear facility; a cutting auxiliary unit that moves together with the mechanical cutting means and selectively heats a position ahead of the movement path of the mechanical cutting means in the structure of a nuclear power facility; and a transfer unit that moves the mechanical cutting means and the cutting auxiliary together. In the method of dismantling a nuclear facility using a cutting device for dismantling a nuclear facility, the structure of the nuclear facility is formed while operating the mechanical cutting means and the cutting auxiliary. A combined cutting step to remove some depth from the outer surface; and a mechanical cutting step of removing the remaining portion removed in the combined cutting step while operating the mechanical cutting means.

The mechanical cutting means includes an end mill and a circular saw. The end mill may be used in the combined cutting step, and the circular saw may be used in the mechanical cutting step.

In the combined cutting step, the transfer unit may move the mechanical cutting means and the cutting auxiliary unit at a certain speed or higher.

The cutting device for dismantling a nuclear power plant further includes a control unit that controls the mechanical cutting means, the cutting auxiliary unit, and the transfer unit, and in the combined cutting step, the control unit according to the temperature of a position in front of the movement path of the mechanical cutting means. The operating speed of the transfer unit can be adjusted.

The cutting device for dismantling a nuclear facility further includes a temperature sensor that measures the temperature at a position ahead of the movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit, and in the combined cutting step, The control unit may adjust the operating speed of the transfer unit according to the measurement result of the temperature sensor.

The cutting device for dismantling a nuclear power plant further includes a data storage unit storing temperature data of the outer surface of the structure of the nuclear power plant for each operating state of the cutting auxiliary unit, and in the combined cutting step, the control unit controls the operating state of the cutting auxiliary unit. The operating speed of the transfer unit can be adjusted based on the data of the data storage unit.

The cutting device for dismantling a nuclear facility further includes a radiation dose measurement sensor that measures the radiation dose along a movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit, wherein the control unit, It can be decided whether to perform the combined cutting step or the mechanical cutting step.

The cutting device for dismantling the nuclear facility further includes a data storage unit storing radioactive material concentration according to the location and depth of the structure of the nuclear facility, and the control unit performs the combined cutting step based on the data of the data storage unit. You can decide whether to perform the mechanical cutting step or not.

In the combined cutting step, the structure of the nuclear facility can be removed several times for each section in the thickness direction of the structure of the nuclear facility.

In the combined cutting step, the width of the section located on the outside of the thickness of the structure of the nuclear facility can be removed to be wider than the width of the section located on the inside.

According to the cutting device for dismantling nuclear facilities according to the present invention, it is possible to safely and easily cut the structure of a nuclear facility.

More specifically, when cutting the outer part of the nuclear facility structure that is not contaminated by radioactive materials, the cutting load during cutting using mechanical cutting means can be reduced by lowering the rigidity by heating the nuclear facility structure above the softening point. When cutting the inner part of a nuclear facility structure contaminated with radioactive materials, the release of radioactive materials can be prevented as much as possible by performing the cutting operation using only mechanical cutting means.

1 is a perspective view of a cutting device for dismantling nuclear power facilities according to the present invention;
Figure 2 is an explanatory diagram of cutting the outer surface of a nuclear facility structure using a cutting device for dismantling a nuclear facility according to the present invention;
Figure 3 is an explanatory diagram of cutting the inner surface of a nuclear facility structure using a cutting device for dismantling a nuclear facility according to the present invention;
Figure 4 is an explanatory diagram of cutting a thick nuclear facility structure in the nuclear facility dismantling method according to the present invention;
5 to 7 are explanatory diagrams of the effect of the cutting device for dismantling nuclear facilities according to the present invention;
Figure 8 is an explanatory diagram of the process of cutting a 25 mm stainless steel plate using a cutting device for dismantling a nuclear facility according to the present invention.

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

The structure of a nuclear facility in which the cutting device (1) for dismantling a nuclear facility according to the present invention is used may be made of high-strength metal, and in terms of the thickness of the structure, the inner portion is contaminated by radioactive materials and the outer portion is contaminated with radioactive materials. It may be uncontaminated.

Figure 1 shows a perspective view of a cutting device 1 for dismantling nuclear power facilities according to the present invention.

The cutting device (1) for dismantling nuclear power facilities according to the present invention includes a mechanical cutting means (2), a cutting auxiliary part (5), and a conveying part (18).

The mechanical cutting means 2 moves along the structure 19 of the nuclear facility and serves to mechanically remove the structure of the nuclear facility from the outer surface. That is, the mechanical cutting means 2 can cut or shave and remove the structure of the nuclear facility.

Here, 'mechanically' removing the structure of a nuclear facility means directly contacting the structure of the nuclear facility and deforming the structure of the nuclear facility with physical external force.

The mechanical cutting means (2) includes a cutting part (7) that applies cutting force while directly contacting the structure (19) of the nuclear facility, a spindle head (8) that holds the cutting part (7), and a rotating spindle head (8). It may include a spindle motor (9), etc.

The cutting auxiliary part 5 moves together with the mechanical cutting means 2 and selectively heats positions ahead of the movement path of the mechanical cutting means 2 in the structure 19 of the nuclear power plant. More specifically, the cutting auxiliary unit 5 heats the structure of the nuclear facility when removing the outer portion that is not contaminated by radioactive materials on the thickness of the structure of the nuclear facility, and heats the structure of the nuclear facility when removing the inner portion that is contaminated by radioactive materials. Do not heat structures in nuclear facilities. Therefore, when cutting the inner part of the structure of a nuclear power facility, the cutting operation is performed using only the mechanical cutting means (2).

The transfer unit 18 serves to move the mechanical cutting means 2 and the cutting auxiliary unit 5 together. In the transfer unit 18, the mechanical cutting means 2 and the cutting auxiliary unit 5 are fixed at a distance from each other. , the transfer unit 18 may be provided with an actuator (not shown) such as a motor or may be fixed to the manipulator 6 and moved. The cutting auxiliary part 5 can be coupled to the conveying part 18 through a mechanical cutting means 2.

According to the cutting device for dismantling nuclear facilities according to the present invention, it is possible to safely and easily cut the structure of a nuclear facility.

That is, when cutting the outer part 13 of the nuclear facility structure, as shown in FIG. 2, the cutting auxiliary part 5 is used to heat the area in front of the moving path of the mechanical cutting means 2 to the softening point or higher. By creating a heat affected zone (14), the rigidity and cutting load of the nuclear facility structure can be reduced. Accordingly, the mechanical cutting means 2 can quickly cut the structure of the nuclear facility, and the possibility of the mechanical cutting means 2 being damaged during cutting is reduced. In addition, the use of cutting oil or coolant for cooling the mechanical cutting means 2 can be eliminated or the amount used can be minimized. The outer part of the nuclear facility structure contains very little radioactive material, so even when heated, little radioactive material is generated.

On the other hand, when cutting the inner part 17 of the nuclear facility structure, as shown in FIG. 3, the cutting operation is performed using only the mechanical cutting means 2 without operating the cutting auxiliary unit 5, thereby preventing contamination. The generation of radioactive materials in the inner part of the nuclear facility structure can be prevented as much as possible.

The mechanical cutting means 2 may comprise, for example, an end mill 7 or a circular saw (not shown).

The end mill (7) has a bar-like overall shape and performs work by standing on the surface of the nuclear facility structure (19), so cutting work can be performed at a close distance from the cutting auxiliary unit (5). Accordingly, the heat-affected area can be cut by the cutting auxiliary unit 5 before the heat-affected area is affected by external air, and as a result, the mechanical cutting means 2 can perform cutting work while receiving a constant small reaction force. there is.

Because the circular saw has a long cutting edge and a relatively thin thickness, it is possible to quickly cut nuclear facility structures while minimizing the amount of cutting.

In other words, the end mill (7) can effectively cut the nuclear facility structure when the mechanical cutting means (2) and the cutting auxiliary unit (5) are used together, and the circular saw can effectively cut the nuclear facility structure using the mechanical cutting means (2) alone. In some cases, nuclear facility structures can be effectively cut.

The end mill 7 can also facilitate the application of the circular saw by forming a cutting groove with a certain width at the position where the circular saw is to be applied.

The end mill (7) and the circular saw are detachably formed on the main body part of the mechanical cutting means (2), so that the end mill (7) can be used depending on whether the mechanical cutting means (2) is used together with the cutting auxiliary part (5). Alternatively, it can be used by replacing it with a circular saw.

The mechanical cutting means 2 may be provided with an index (not shown) to which the end mill 7 and the circular saw are fixed. An end mill (7) and a circular saw are fixed to the index, and the rotation or linear movement of the index moves the end mill (7) or circular saw to a position where it can cut the structure of a nuclear power facility. Accordingly, either the end mill 7 or the circular saw can be selectively used.

The cutting assistant 5 can heat the structure of a nuclear power facility using, for example, a plasma torch 3.

In order for the mechanical cutting means (2) to smoothly cut the structure of a nuclear facility, the width of the heat-affected area must be formed to be larger than the width of the part (to-be-cut portion) cut by the mechanical cutting means (2).

The plasma torch 3 is capable of creating an arc column 15 of sufficient width and a corresponding heat affected area 14 by adjusting the output, gas flow rate, and nozzle diameter.

When the plasma torch (3) is moved along the surface of the structure of a nuclear power facility, the heat-affected area expands to form a long trajectory (16), and the mechanical cutting means (2) moves along the plasma torch (3) to form this trajectory ( 16) will be removed.

The plasma torch 3 may specifically be a transfer type direct current arc plasma torch 3 or a non-transfer type direct current plasma torch 3.

For reference, when the plasma torch 3 is a transfer type direct current arc plasma torch 3, the heat-affected area may include welding chips, cuffs, and arc-eroded spaces formed on the surface of the nuclear facility structure.

The width and depth of the heat-affected area formed by the plasma torch (3) can be adjusted by adjusting the output or moving speed of the plasma torch (3) according to the specifications of the cutting part (7) that constitutes the mechanical cutting means (2). .

For example, when cutting a stainless steel 316 thick plate, for an end mill (7) with a diameter of 16 mm and a length of 100 mm, the output of the plasma torch (3) is set to 10 kW and the feed speed is set to 200 mm/min, so that the width is 20 mm and the depth is 20 mm. It can create internal and external heat affected areas.

The cutting auxiliary unit 5 may be provided with a position adjusting unit 4.

The position control unit 4 serves to rotate and move the plasma torch 3 based on the transfer unit 18. For example, the cutting auxiliary unit 5 may be coupled to the mechanical cutting means 2 through the position adjusting unit 4, and the mechanical cutting means 2 may be coupled to the conveying unit 18.

Specifically, the position control unit 4 is a rotation stage 12 that rotates the plasma torch 3 about an axis that intersects the movement path of the mechanical cutting means 2 and is located parallel to the surface of the nuclear facility structure. , a first linear stage 10 that moves the rotation stage 12 along the direction of the rotation axis of the rotation stage 12, and a first linear stage 10 that moves the first linear stage 10 along a direction intersecting the surface of the nuclear facility structure. Shiki may be provided with a second linear stage 11.

By this position adjusting unit 4, the angle and distance of the plasma torch 3 with respect to the mechanical cutting means 2 can be adjusted, and the angle and distance of the plasma torch 3 with respect to the nuclear facility structure can be adjusted. there is. The angle and position of the plasma torch (3) can be adjusted according to the material of the nuclear facility structure or the depth of the nuclear facility structure to be cut by using the mechanical cutting means (2) and the cutting assistant (5) together. Accordingly, it is possible to control the degree to which the plasma torch (3) heats the nuclear facility structure and the degree to which it is exposed to the outside air after the heat-affected zone is created and before it is cut by the mechanical cutting means (2).

The arc columns 15 generated from the mechanical cutting means 2 and the plasma torch 3 are preferably formed to be spaced apart from each other by a certain distance or more. The plasma torch 3 may be spaced apart from the mechanical cutting means 2 by a distance such that the arc plume does not soften the mechanical cutting means 2 .

Accordingly, it is possible to prevent the rigidity of the mechanical cutting means (2) from being reduced due to heat, and as the mechanical cutting means (2) cuts the heat-affected area where the temperature is too high, viscous chips are formed on the cutting part (7). It can prevent fusion.

The cutting device 1 for dismantling nuclear power facilities according to the present invention may further include a control unit (not shown).

The control unit controls the mechanical cutting means (2), the cutting auxiliary unit (5), and the conveying unit 18. In particular, depending on the depth from the outer surface of the structure of the nuclear power plant, whether the cutting auxiliary unit (5) operates and whether the cutting auxiliary unit (5) operates. Determine operating conditions.

That is, the control unit automatically determines the state of the cutting assistant 5 without the operator, thereby preventing the operator from being exposed to radioactive materials generated during the cutting process.

The cutting device 1 for dismantling a nuclear facility according to the present invention may be equipped with a radiation dose measurement sensor (not shown) capable of measuring the concentration of radioactive materials in the nuclear facility structure. The radiation dose measurement sensor measures the radiation dose along the movement path of the mechanical cutting means (2) in the nuclear facility structure and transmits the measurement results to the control unit, and the control unit controls the cutting auxiliary unit (5) according to the measurement results of the radiation dose measurement sensor. You can decide whether to operate or not. In other words, based on the radiation dose at the location to be cut using the cutting device (1) for dismantling nuclear power facilities according to the present invention, if the radiation dose is below the standard value, the mechanical cutting means (2) and the cutting auxiliary unit (5) are used together. And if the radiation dose is above the standard value, only mechanical cutting means (2) can be used.

Since the radiation dose in a nuclear facility structure may vary depending on the location and depth, the radiation dose measurement sensor can measure at certain sections in the longitudinal, width, and depth directions of the nuclear facility structure, especially depending on the depth of the nuclear facility structure. Since the radiation dose can vary significantly, the radiation dose can be measured whenever the cutting depth changes.

In contrast, the cutting device 1 for dismantling nuclear facilities according to the present invention is provided with a data storage unit (not shown) that stores radioactive material concentrations according to the location and depth of the nuclear facility structure, and cuts based on the data in the data storage unit. It is possible to determine whether or not the auxiliary unit 5 is operating.

The cutting device 1 for dismantling nuclear facilities according to the present invention may further include a temperature sensor (not shown).

The temperature sensor measures the temperature at a position ahead of the movement path of the mechanical cutting means (2) in the structure of the nuclear facility and transmits the measurement results to the control unit, and the control unit adjusts the operating speed of the transfer unit (18) according to the measurement results of the temperature sensor. do.

If the temperature at the front position of the movement path of the mechanical cutting means (2) is too low, the structure of the nuclear facility may be less softened and a large reaction force may be generated in the mechanical cutting means (2), and if the temperature is too high, the structure of the nuclear facility may become less soft. The viscosity of the chips generated while cutting is high, so the degree of fusion to the mechanical cutting means (2) may increase.

And, if the transfer unit 18 moves the cutting auxiliary unit 5 too quickly, the structure of the nuclear facility may not be sufficiently heated, and if the transfer unit 18 moves the cutting auxiliary unit 5 too slowly, the structure of the nuclear facility may not be heated sufficiently. The structure may become heated more than necessary.

Therefore, when the temperature of the structure of the nuclear facility measured by the temperature sensor is such that a large reaction force is not generated in the mechanical cutting means 2 and the viscosity of the chip does not become too high, the mechanical cutting means 2 is in the heat affected area. The operating speed of the transfer unit 18 is controlled so that it can be cut.

Since the stiffness or softening degree of the nuclear facility structure may vary at the same temperature depending on the material of the nuclear facility structure, the control unit may determine the operating speed of the transfer unit 18 by considering the material of the nuclear facility structure in addition to the measurement results from the temperature sensor. there is.

Data regarding the material of the nuclear facility structure may be stored in a data storage unit (not shown) and transmitted to the control unit.

In contrast, the cutting device 1 for dismantling nuclear power facilities according to the present invention does not have a temperature sensor, and determines the position and angle of the cutting auxiliary unit 5 relative to the nuclear facility structure, the output of the cutting auxiliary unit 5, and the material of the nuclear facility structure. , a data storage unit in which data on the temperature of the nuclear facility structure according to the moving speed of the cutting auxiliary unit 5 is stored, and the control unit determines the current operating state of the cutting auxiliary unit 5 and the conditions of the nuclear facility structure material to be cut. A method of calculating the moving speed of the cutting assistant 5 to bring the structure to a specific temperature can also be used.

Hereinafter, the method for dismantling a nuclear facility according to the present invention will be described.

While explaining the method of dismantling a nuclear facility according to the present invention, detailed description of the parts mentioned in the description of the cutting device 1 for dismantling a nuclear facility according to the present invention may be omitted.

In the nuclear facility dismantling method according to the present invention, a mechanical cutting means (2) moves along the structure of the nuclear facility and mechanically removes the structure of the nuclear facility, and moves along with the mechanical cutting means (2) to remove the structure of the nuclear facility. A nuclear power plant comprising a cutting auxiliary unit (5) that selectively heats a position ahead of the movement path of the mechanical cutting means (2), and a transfer unit (18) that moves the mechanical cutting means (2) and the cutting auxiliary unit (5) together. Use a cutting device (1) to dismantle the facility.

The nuclear facility dismantling method according to the present invention largely includes a combined cutting step and a mechanical cutting step.

In the combined cutting step, the mechanical cutting means (2) and the cutting auxiliary unit (5) are operated together to remove some depth from the outer surface of the structure of the nuclear power facility. More specifically, when the cutting auxiliary unit 5 heats the outer surface of the nuclear facility structure to create a heat-affected zone, the mechanical cutting means 2 located behind the cutting auxiliary unit 5 creates the heat-affected zone by mechanical means. Remove it with

The heat-affected area has reduced rigidity compared to other parts that are not heated, so it can be easily removed with a mechanical cutting means (2). When removed, the reaction force applied to the mechanical cutting means (2) is not large, so the mechanical cutting means (2) can be easily removed. Less likely to be damaged.

In addition, a portion of the depth from the outer surface of the structure of the nuclear facility that is removed in the combined cutting step is a section that is almost uncontaminated by radioactive materials, and even when heated, almost no radioactive materials are generated.

In the mechanical cutting step, only the mechanical cutting means (2) is operated to remove the portion remaining after the combined cutting step on the thickness of the structure of the nuclear facility.

In the structure of a nuclear facility, the remaining part after the combined cutting step is carried out on the inner side of the nuclear facility structure may be contaminated with radioactive materials. In the mechanical cutting step, only the mechanical cutting means (2) is used to reduce heat as much as possible. By preventing this from occurring, you can prevent radioactive materials from being released.

When the mechanical cutting means (2) according to the present invention includes an end mill (7) and a circular saw, the end mill (7) can be used in the combined cutting step and the circular saw can be used in the mechanical cutting step.

The end mill (7) can cut the heat-affected area before the heat-affected area is affected by external air, so it can not only effectively cut the nuclear facility structure in the combined cutting step, but also provide a schedule that can facilitate the application of the circular saw. It can provide cutting grooves of any width, and because the circular saw has a long cutting edge and a relatively thin thickness, it can effectively cut nuclear facility structures while minimizing the amount of cutting in the mechanical cutting stage.

In the combined cutting step, it is preferable that the transfer unit 18 moves the mechanical cutting means 2 and the cutting auxiliary unit 5 at a certain speed or higher.

If the cutting auxiliary unit (5) moves too slowly, the temperature of the heat-affected area may become too high, causing a problem in which chips generated during cutting are fused to the mechanical cutting means (2). Therefore, in the combined cutting step, the mechanical cutting means (2) may be used. ) and the cutting auxiliary unit (5) are moved at a certain speed or higher.

On the other hand, if the cutting auxiliary unit 5 moves too quickly, the heat-affected area may be narrow or the temperature may be too low, resulting in a large reaction force during cutting, so the mechanical cutting means 2 and the cutting auxiliary unit 5 may be moved too quickly. Moving it is also not desirable.

When the cutting device 1 for dismantling a nuclear power plant further includes a control unit, in the combined cutting step, the control unit can adjust the operating speed of the transfer unit 18 according to the temperature at a position ahead of the movement path of the mechanical cutting means 2. .

That is, the control unit can adjust the speed of the cutting assistant 5 so that the heat-affected area is not heated too much or too little by the cutting assistant 5.

The temperature at a position ahead of the movement path of the mechanical cutting means 2 can be measured in real time by a temperature sensor and the measurement results can be transmitted to the control unit.

If the temperature measurement result is lower than the standard value, the control unit controls the transfer unit 18 to transfer the mechanical cutting means 2 and the cutting auxiliary unit 5 more slowly. If the temperature measurement result is higher than the standard value, the transfer unit 18 controls the transfer unit 18 to transfer the mechanical cutting means 2 and the cutting auxiliary unit 5 more slowly. The mechanical cutting means (2) and the cutting auxiliary unit (5) can be controlled to move faster.

Control of the operating speed of the transfer unit 18 by the control unit may be based on data from a data storage unit that stores temperature data on the outer surface of the nuclear facility structure for each operating state of the cutting auxiliary unit 5.

The operating state of the cutting auxiliary unit 5 may include the moving speed of the cutting auxiliary unit 5, the output of the cutting auxiliary unit 5, etc. And the conditions for determining the temperature from the temperature data may further include the material conditions of the nuclear facility structure in addition to the operating state conditions of the cutting auxiliary unit 5.

In this case, in the combined cutting step, the control unit can find a temperature that meets the conditions in the data storage unit based on the current operating state of the cutting auxiliary unit 5 and the material of the nuclear facility structure. And the operating speed of the transfer unit 18 can be adjusted based on the found temperature.

If the cutting device 1 for dismantling nuclear power facilities according to the present invention further includes a radiation dose measurement sensor, the control unit may decide whether to perform a combined cutting step or a mechanical cutting step according to the measurement results of the radiation dose measurement sensor. there is.

The control unit performs a combined cutting step when the radioactive material measurement result at the location where the cutting device (1) for dismantling nuclear power facilities wants to cut is lower than the standard value, and performs a mechanical cutting step when the radioactive material measurement result is higher than the standard value. To perform this, the operations of the mechanical cutting means (2), the cutting auxiliary unit (5), and the conveying unit (18) are controlled.

Accordingly, since it is possible to accurately determine at which position to perform the combined cutting step or the mechanical cutting step, cutting work on the nuclear facility structure can be performed more effectively and safely.

The decision of the cutting step by the control unit may be made based on data from a data storage unit that stores the radioactive material concentration according to the location and depth of the nuclear facility structure.

In other words, the cutting device (1) for dismantling nuclear facilities can determine the location and depth of the cutting operation, and find the radioactive material concentration at that location and depth in the data storage unit. And based on the found radioactive material concentration, it can be decided whether to perform a combined cutting step or a mechanical cutting step.

In the combined cutting step, cutting operations can be performed several times at each section on the thickness of the nuclear facility structure.

The structure of a nuclear facility can be thick for safety, and even if most sections of the thickness of the structure of a nuclear facility are uncontaminated, cutting the uncontaminated section at once creates a large reaction force in the mechanical cutting means (2) during cutting. This can cause problems with long chips being formed. In addition, long-length chips may cause problems such as reduced cutting efficiency and the cutting portion 7 of the mechanical cutting means 2 being caught in the workpiece (structure of a nuclear power facility) and being damaged during cutting.

Specifically, when the chip is formed long, it becomes difficult for the chip to be easily ejected from the cutting area, causing the chip to more easily attach to the mechanical cutting means (2), causing the problem of tool breakage and the heat generated by the cutting assistant (5). Problems that make discharge difficult may occur.

Accordingly, as shown in (a) of FIG. 4, it is possible to use a method of cutting the outermost section of the nuclear facility structure and then gradually cutting the sections below it one by one. In this case, since the chips generated by cutting are in a short shape, they can be easily discharged from the cutting area, thereby preventing problems caused by chips not being discharged smoothly. In addition, since no significant reaction force is generated in the mechanical cutting means (2) during cutting, the possibility of damage to the mechanical cutting means (2) can be reduced.

The width of the groove formed by cutting the outer section of the nuclear facility structure is determined by the cutting portion (7) to reduce friction with the side of the cutting portion (7) constituting the mechanical cutting means (2) when cutting the section below. It can be formed to be about 10% wider than the diameter.

When cutting is performed several times for each section on the thickness of the nuclear facility structure as above, as shown in (b) of FIG. 4, the width of the section located outward on the thickness of the nuclear facility structure is It can be removed wider than the width of the section located on the inside.

The end mill (7), which can be used as a mechanical cutting means (2) in the combined cutting step, has the tool holder (20) of the spindle head (8) because the direction in which the tool extends intersects with the direction of the reaction force during cutting. If you hold (7) long, the end mill (7) may be damaged more easily than if you hold it short. On the other hand, if the end mill 7 is held short, a problem may occur in which the tool holder and the nuclear facility structure interfere when cutting a deep part of a nuclear facility structure having a large thickness.

Therefore, the width of the section located outside of the thickness of the nuclear facility structure is formed to be larger than the diameter of the tool holder to prevent the tool holder and the nuclear facility structure from interfering when cutting a deep part of the nuclear facility structure.

If the width of the section located on the outside of the thickness of the nuclear facility structure is made larger than the width of the section located on the inside, the effect of smoothly dissipating heat through the cut part of the nuclear facility structure is also exerted, resulting in chipping by stagnant heat. The problem of increased viscosity can be prevented.

In the above, the outer surface portion of the nuclear facility structure that is not contaminated by radioactive materials is cut using a combination of mechanical cutting means (2) and the cutting auxiliary unit (5), and the inner surface portion of the nuclear facility structure that is contaminated by radioactive materials is mechanically cut. Although it was explained that cutting can be done only with the means (2), if an unexpected situation occurs in which the mechanical cutting means (2) is damaged during work, cutting work can also be performed using only the plasma torch (3) of the cutting assistant (5). do.

Cutting work using only the plasma torch (3) can be determined by considering the decrease in work efficiency and worker safety resulting from replacing the damaged mechanical cutting means (2).

Hereinafter, the effects of the present invention will be described in more detail through specific examples of the present invention.

However, the following examples are for illustrating the specific application of the present invention, and the scope of the present invention is not limited to the examples.

Example 1

In the cutting device (1) for dismantling nuclear power facilities according to the present invention, 25 mm thick stainless steel 316L was cut by using a mechanical cutting means (2) and a cutting assistant (5) in combination. Specifically, a 16 mm SUS-CUT end mill (7) was used as the end mill (7) constituting the mechanical cutting means (2), the cutting depth was 13 mm, and the movement of the mechanical cutting means (2) and the cutting auxiliary unit (5) was used. The speed was 200 mm/min and the cutting length was 150 mm. The rotation speed of the end mill (7) was set to 1,000 rpm, and the arc current of the plasma torch (3) constituting the cutting auxiliary part (5) was set to 60 A.

In Figure 5 (a), voltage value waveform data for the load of the spindle motor 9 that operates the end mill 7 under the above conditions is shown along with its average value. When a cutting process is performed with an end mill (7) while creating a heat-affected zone with a plasma torch (3), it can be confirmed that an average voltage value of about 1.58 V is obtained, as shown in (a) of FIG. 5. there is.

Comparative example One

In Comparative Example 1, cutting work was performed under the same conditions as Example 1 except for using the plasma torch (3). That is, cutting work was performed only with the end mill (7).

In Figure 5 (b), voltage value waveform data for the load of the spindle motor 9 that operates the end mill 7 in Comparative Example 1 is shown along with its average value. When the cutting process is performed using only the end mill 7, it can be confirmed that the average voltage value is approximately 2.27V, as shown in (b) of FIG. 5.

In summary, when the end mill (7) was used in combination with the plasma torch (3), the load was reduced by about 30% or more compared to the case where the end mill (7) was not used.

Example 2

A 25 mm stainless steel 316L steel plate was cut until the 16 mm end mill (7) was broken without lubricant or coolant under the conditions of cutting depth of 17 mm, feed speed of 200 mm/min, and end mill (7) rotation speed of 1,000 rpm. A current of 40A was passed through the plasma torch (3).

Figure 6 (a) is a photograph of the surface of a stainless steel sheet after the above operation. As shown in (a) of FIG. 6, when the end mill 7 is used in combination with the plasma torch 3, it is possible to perform a total cutting process of about 850 mm without fatal damage to the end mill 7. did.

Comparative example 2

In Comparative Example 2, the cutting operation was performed in the same manner as Example 2, except for using the plasma torch (3).

Figure 6 (b) is a photograph of the surface of a stainless steel sheet after work according to Comparative Example 2. As shown in (b) of FIG. 6, when only the end mill 7 was used, the end mill 7 was damaged after cutting about 100 mm. It can be seen that not only the blade of the end mill (7) but also the body was broken, indicating that a very strong reaction force was applied to the end mill (7) according to Comparative Example 2.

In summary, when the end mill 7 is used in combination with the plasma torch 3, the lifespan of the end mill 7 can be dramatically improved by about 850% or more compared to the case where the end mill 7 is not used.

Example Lesson 3 Comparative example 3

Figure 7 shows the cutting capacity for each diameter of the end mill 7 when cutting a 25 mm thick stainless steel 316L sheet in the case where the plasma torch 3 is used together (Example 3) and when the plasma torch 3 is not used (Comparative Example 3). The results of an experiment to determine depth are shown. In each case, a carbide end mill (7) (SUS-CUT) was used as the end mill (7), and the feed speed of the end mill (7) was 200 mm/min and the rotation speed was 1,000 rpm. When the plasma torch 3 was used together, the arc current of the plasma torch 3 was set to 40A.

7, regardless of whether the plasma torch (3) is used in combination, the cutting depth increases as the tool diameter increases. This means that in the case of the end mill (7), the greater the number of blades and the larger the diameter, the greater the risk of destruction. Because the resistance strength increases, this phenomenon can be said to be a general phenomenon that appears as the diameter of the end mill (7) increases.

However, when the plasma torch (3) is used together, it can be seen that the depth that can be cut without tool destruction increases by at least 40% at the same feed speed. In other words, it can be seen that when the plasma torch 3 is used together, the cutting depth of the end mill 7 is significantly increased due to a reduction in the cutting load.

Example 4

Based on the results of Examples 1 to 3, a cutting process was performed on a 316L stainless steel plate with a width of 150 mm and a thickness of 25 mm to be cut. Figure 8 shows each process of the cutting process according to Example 4.

In Example 3, it was confirmed that a cutting depth of 21 mm is guaranteed at a speed of 200 mm/min or more when the carbide end mill (7) is used in combination with the plasma torch (3), so for a 25 mm thick plate, i) the plasma torch (3) A step of cutting to a depth of 21 mm at a speed of 200 mm/min (Figure 8 (a)), ii) a step of cutting the remaining 4 mm at a speed of 200 mm/min using only the end mill (7) (Figure 8 (b)) ) was performed through the cutting process. In the cutting step using the plasma torch 3, the end mill 7 was rotated at a speed of 1,000 rpm, and the arc current of the plasma torch 3 was 60A.

As a result of performing the cutting operation in the same manner as above, it took a total of 90 seconds, and the time taken to cut to a depth of 21mm using the dual plasma torch (3) was 45 seconds, and the remaining 4mm was removed using the end mill (7) alone. The time taken was measured to be 45 seconds. In other words, the cutting speed when using the plasma torch (3) is 4,200 mm ³ /min, while the cutting speed when using the end mill (7) alone is 800 mm ³ /min, and the cutting speed is 5 times higher due to the plasma torch (3). You can see that it is faster.

In addition, the cutting process used in Example 4 is to quickly cut the outer surface portion of the structure of a nuclear power facility that is not contaminated by radioactive materials using a mechanical cutting means (2) and the cutting auxiliary unit (5), and to quickly cut the outer surface portion that is not contaminated by radioactive materials. It is shown that the contaminated inner surface part can be safely cut using mechanical cutting means (2). In other words, it clearly shows the advantages of the cutting device 1 according to the present invention as one of the cutting processes for dismantling a nuclear reactor.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. It is considered to be within the scope of the claims of the present invention to the extent that anyone skilled in the art can make modifications without departing from the gist of the invention as claimed in the claims.

1: Cutting device for dismantling nuclear facilities
2: Mechanical cutting means 3: Plasma torch
4: Position control part 5: Cutting auxiliary part
7: End mill 18: Transfer unit

Claims (20)

In a cutting device for dismantling nuclear facilities,
Mechanical cutting means for mechanically removing the structure of the nuclear facility while moving along the structure of the nuclear facility;
a cutting auxiliary unit that moves together with the mechanical cutting means and selectively heats a position ahead of the movement path of the mechanical cutting means in the structure of a nuclear power facility;
a transfer unit that moves the mechanical cutting means and the cutting auxiliary unit together;
a control unit that controls the mechanical cutting means, the cutting auxiliary unit, and the transfer unit;
A data storage unit storing radioactive material concentrations according to the location and depth of the nuclear facility structure; and
It includes a radiation dose measurement sensor that measures the radiation dose along the movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit,
The control unit,
Determining whether to operate the cutting auxiliary unit according to the data of the data storage unit and the measurement result of the radiation dose measurement sensor,
The cutting auxiliary part,
plasma torch; and
A cutting device for dismantling a nuclear facility comprising a position control unit that rotates and moves the plasma torch up, down, left and right based on the transfer unit.
According to paragraph 1,
A cutting device for dismantling nuclear power facilities, characterized in that the mechanical cutting means includes an end mill or circular saw.
According to paragraph 2,
A cutting device for dismantling nuclear power facilities, characterized in that the end mill and the circular saw are formed to be detachable.
According to paragraph 2,
A cutting device for dismantling nuclear power facilities, characterized in that the mechanical cutting means has an index to which the end mill and the circular saw are fixed.
According to paragraph 1,
The cutting auxiliary part is coupled to the mechanical cutting means through the position adjusting part,
A cutting device for dismantling nuclear power facilities, characterized in that the mechanical cutting means is coupled to the transfer unit.
According to paragraph 1,
The position control unit,
a rotation stage that rotates the plasma torch about an axis that intersects the movement path of the mechanical cutting means and is located parallel to the surface of the nuclear facility structure;
a first linear stage that moves the rotation stage along a direction of the rotation axis of the rotation stage; and
A cutting device for dismantling a nuclear facility, comprising a second linear stage that moves the first linear stage along a direction intersecting the surface of the nuclear facility structure.
According to clause 5,
A cutting device for dismantling nuclear power facilities, characterized in that the arc column generated from the mechanical cutting means and the plasma torch are spaced apart from each other by a certain distance or more.
delete According to paragraph 1,
It further includes a temperature sensor that measures the temperature at a position ahead of the movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit,
A cutting device for dismantling nuclear power facilities, wherein the control unit adjusts the operating speed of the transfer unit according to the measurement result of the temperature sensor.
delete Mechanical cutting means for mechanically removing the structure of the nuclear facility while moving along the structure of the nuclear facility; a cutting auxiliary unit that moves together with the mechanical cutting means and selectively heats a position ahead of the movement path of the mechanical cutting means in the structure of a nuclear power facility; a transfer unit that moves the mechanical cutting means and the cutting auxiliary unit together; a control unit that controls the mechanical cutting means, the cutting auxiliary unit, and the transfer unit; A data storage unit storing radioactive material concentrations according to the location and depth of the nuclear facility structure; and a radiation dose measurement sensor that measures the radiation dose along the movement path of the mechanical cutting means in the structure of a nuclear power facility and transmits the measurement result to the control unit, wherein the cutting assistant unit includes a plasma torch; and a position control unit that rotates and moves the plasma torch up, down, left, and right based on the transfer unit. In a method of dismantling a nuclear facility using a cutting device for dismantling a nuclear facility, including:
A combined cutting step of removing a portion of the depth from the outer surface of the structure of the nuclear facility while operating the mechanical cutting means and the cutting auxiliary unit; and
A mechanical cutting step of removing the remaining portion removed in the combined cutting step while operating the mechanical cutting means,
The control unit determines whether to perform the combined cutting step or the mechanical cutting step according to the data of the data storage unit and the measurement result of the radiation dose measurement sensor.
According to clause 11,
The mechanical cutting means includes an end mill and a circular saw,
In the combined cutting step, the end mill is used,
A method of dismantling a nuclear facility, characterized in that the circular saw is used in the mechanical cutting step.
According to clause 11,
In the combined cutting step, the transfer unit moves the mechanical cutting means and the cutting auxiliary unit at a certain speed or more.
According to clause 11,
In the combined cutting step, the method of dismantling a nuclear facility, wherein the control unit adjusts the operating speed of the transfer unit according to the temperature of a position ahead of the movement path of the mechanical cutting means.
According to clause 14,
The cutting device for dismantling a nuclear facility further includes a temperature sensor that measures the temperature at a position ahead of the movement path of the mechanical cutting means in the structure of the nuclear facility and transmits the measurement result to the control unit,
In the combined cutting step, the nuclear facility decommissioning method is characterized in that the control unit adjusts the operating speed of the transfer unit according to the measurement result of the temperature sensor.
According to clause 14,
In the data storage unit, temperature data of the outer surface of the structure of the nuclear facility for each operating state of the cutting auxiliary unit is stored,
In the combined cutting step, the nuclear facility decommissioning method is characterized in that the control unit adjusts the operating speed of the transfer unit based on the operating state of the cutting auxiliary unit and the data of the data storage unit.
delete delete According to clause 11,
In the combined cutting step, a method of dismantling a nuclear facility, characterized in that the structure of the nuclear facility is removed several times for each section in the thickness direction of the nuclear facility structure.
According to clause 14,
In the combined cutting step,
A method of dismantling a nuclear facility, characterized in that the width of the section located on the outside of the thickness of the structure of the nuclear facility is wider than the width of the section located on the inside.

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