JP2010019700A - Method for work on structure and shielding unit in nuclear power plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely carry out work by easily reducing radiation doses spread to workers while applying a shield where a container is filled with water. <P>SOLUTION: The method includes processes of: placing a shielding container 2 whose flexible and stretchable coverture 21 is expanded by filling a fluid into a sealed region covered with the coverture 21 in a desired position inside a primary coolant pipe 150 with the coverture 21 deflating; expanding the shielding container 2 by supplying air to it; composing a wall-shaped shield for shielding from radiation by covering the desired position inside the primary coolant pipe 150 with the shielding container 2 filled with water by exhausting air from it while supplying water to it; and carrying out a work in a region shielded from radiation by the shield. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an in-structure work method for performing work such as inspection and repair in a structure of a nuclear power plant, and a shielding device for reducing the amount of radiation irradiated to an operator in the work in the structure. .

  At the nuclear power plant, the structure is regularly inspected. And the defect part recognized as needing repair by inspection is repaired suitably. Thus, in a nuclear power plant, work such as inspection and repair is required to maintain a normal operating state. In such work, an operator may enter the structure of the nuclear power plant from the manhole. In this case, it is necessary to reduce the radiation dose irradiated to the worker.

  Therefore, it is conceivable to install a wall-shaped shield for shielding radiation in the structure. However, in order to reduce the radiation dose, for example, a shield having a weight exceeding 100 kg is required. And it is not easy to carry the shield of such weight from the manhole into the structure.

  Conventionally, for example, Patent Document 1 discloses a pipe cleaning method for separating a pipe cleaning area and a non-cleaning area by simple means. In this cleaning method, a balloon is inserted into the boundary between the cleaning area and the non-cleaning area of the pipe, and the balloon is pressurized by supplying a fluid such as air or water into the balloon to pressurize the balloon. Isolate from unwashed areas.

  That is, it is conceivable to apply the conventional cleaning method to the work in the structure of the nuclear power plant and shield the inside of the structure with a shield filled with water in the balloon to reduce the radiation dose irradiated to the worker. .

JP 2003-80192 A

  However, when water is supplied into the balloon, since the water is stored in the lower part of the balloon at the beginning of the supply, the balloon does not inflate evenly and the position and orientation of the balloon cannot be determined. Moreover, the position and orientation of the balloon cannot be adjusted due to the weight of water. As a result, it has been difficult for the shielding body that fills the balloon with water to inflate the balloon as a wall so as to shield radiation and to arrange it as intended.

  The present invention solves the above-described problems, and can apply a shield in which a container is filled with water, and can easily reduce the amount of radiation irradiated to an operator and perform the work safely. An object of the present invention is to provide an in-structure working method and a shielding device.

  In order to achieve the above object, the in-structure operation method according to the present invention is an in-structure operation method for performing an operation in a structure of a nuclear power plant, which is sealed with a flexible outer skin. A step of arranging a shielding container in which the outer skin is filled with a fluid and the outer skin swells in a desired position inside the structure with the outer skin deflated, and then inflating by supplying air to the shielding container And a wall-shaped shielding body that covers the desired position in the structure and shields radiation by the shielding container filled with water by exhausting water while supplying water to the shielding container. And a step of performing an operation in an area where radiation is shielded by the shield.

  This working method in the structure is once supplied to the inside of the shielding container and then exhausted while being supplied with water. Therefore, the position and orientation in the structure can be adjusted at the time of supplying air, and when the water is filled The shape is stable. For this reason, the shielding body filled with water inside can be applied. And the radiation amount irradiated to the worker who performs work in a structure with this shield can be reduced easily, and work can be performed safely.

  In order to achieve the above-described object, according to the shielding apparatus of the present invention, the shielding apparatus shields radiation applied to a work area in a structure of a nuclear power plant, and is covered with a flexible outer skin. A shielding container in which a sealed area is filled with fluid and the outer skin expands, a supply / exhaust means for supplying or exhausting air to or from the shielding container, and a water supply / drainage means for supplying or draining water to or from the shielding container. It is characterized by that.

  According to this shielding apparatus, the in-structure work method can be implemented, and the amount of radiation applied to the worker who performs the work in the structure can be easily reduced to perform the work safely.

  Further, the shielding apparatus of the present invention is characterized by comprising monitoring means for monitoring the swelled state or the deflated state of the shielding container disposed inside the structure outside the structure.

  According to this shielding apparatus, the operator can monitor the state of the shielding container without entering the inside of the structure.

  Further, in the shielding apparatus of the present invention, the shielding container is provided with a holding member that forms a leg that is disposed inside the structure in a deflated form and that holds a shape in which the shielding container is swollen. It is characterized by having.

  According to this shielding device, the position and orientation in the structure of the shielding container before the outer skin swells can be maintained by the holding members that form the legs. In addition, the shape of the shielding container in which the outer skin swells can be held by the holding member forming the frame.

  In the shielding device of the present invention, the shielding container is formed in advance in an outer shape along the inner peripheral shape of the structure in a state where the sealed area is filled with fluid and the outer skin swells. To do.

  According to this shielding apparatus, since the shielding container swells in accordance with the inner peripheral shape of the structure and appropriately closes the inside of the structure, the radiation shielding effect can be improved and the radiation dose can be further reduced.

  In the shielding device of the present invention, the structure includes a support member that covers and defines a desired work area inside the structure and supports the shielding container on the outer periphery thereof.

  According to this shielding device, the shielding container can be applied even when a shielding body covering the work area is configured.

  Moreover, in the shielding apparatus of this invention, the said shielding container is divided | segmented and formed in multiple, Each is combined and it makes one shielding body, It is characterized by the above-mentioned.

  According to this shielding device, the shielding member can be applied even when the area where the shielding body is disposed is relatively wide.

  According to the present invention, since the inside of the shielding container is once supplied with air and then exhausted while being supplied with water, the position and orientation in the structure can be adjusted at the time of supplying air, and the shape when filled with water is Stabilize. For this reason, the shielding body filled with water inside can be applied. And the radiation amount irradiated to the worker who performs work in a structure with this shield can be reduced easily, and work can be performed safely.

  Embodiments of an in-structure operation method and a shielding device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is an explanatory diagram showing a configuration of a steam generator of a nuclear power plant, FIG. 2 is a schematic diagram showing a nozzle portion of the steam generator shown in FIG. 1, and FIG. 3 is a structure according to an embodiment of the present invention. It is a flowchart which shows the maintenance operation | work process of a steam generator nozzle including the work method in goods.

  In this embodiment, an in-structure work method and a shield included in maintenance work for a steam generator nozzle of a nuclear power plant will be described.

  The nuclear power plant 100 includes, for example, a pressurized water light reactor nuclear power generation facility (see FIG. 1). In this nuclear power plant 100, a reactor vessel 110, a pressurizer 120, a steam generator 130, and a pump 140 are sequentially connected by a primary coolant pipe 150, thereby forming a primary coolant circulation path (primary system circulation path). Yes. Further, a secondary coolant circulation path (secondary system circulation path) is formed between the steam generator 130 and the turbine (not shown).

  In this nuclear power plant 100, the primary coolant is heated in the reactor vessel 110 to become high temperature and high pressure, and is pressurized by the pressurizer 120 to maintain the pressure constant, while the steam is passed through the primary coolant pipe 150. It is supplied to the generator 130. In the steam generator 130, the primary coolant flows into the inlet-side water chamber 131 and is supplied from the inlet-side water chamber 131 to the U-shaped and plural heat transfer tubes 132. And heat exchange with a primary coolant and a secondary coolant is performed in the heat exchanger tube 132, and a secondary coolant evaporates and becomes steam. Then, when the secondary coolant that has become steam is supplied to the turbine, the turbine is driven to generate power. The primary coolant that has passed through the heat transfer tube 132 is recovered from the outlet water chamber 133 to the pump 140 side via the primary coolant tube 150.

  In the steam generator 130, an inlet nozzle 135 is provided in the inlet-side water chamber 131, and the inlet-side primary coolant pipe 150 is welded to the inlet nozzle 135. The inlet nozzle 135 and the primary coolant pipe 150 are connected via an elbow pipe 151 serving as a joint. The inlet nozzle 135 and the primary coolant pipe 150 are welded to each end of the elbow pipe 151. (See FIG. 2). Similarly, the outlet side water chamber 133 is provided with an outlet nozzle (not shown), and the outlet side primary coolant pipe 150 is welded to the outlet nozzle. The inlet side water chamber 131 and the outlet side water chamber 133 are partitioned through a partition plate 134. In addition, the entrance-side water chamber 131 and the exit-side water chamber 133 are respectively provided with manholes 137 for workers to enter and exit the water chamber (see FIG. 2).

  In the steam generator 130 which is one of the structures of the nuclear power plant 100 having such a configuration, the maintenance work of the inlet nozzle 135 is performed as follows (see FIG. 3). Here, as the maintenance work of the inlet nozzle 135, the repair of the welded portion 152 between the inlet nozzle 135 and the elbow pipe 151 (including the in-structure work method according to the present embodiment) is illustrated.

  Before repairing the welded part 152, the welded part 152 is inspected. In this inspection, the presence or absence of defects such as scratches and cracks is detected by an eddy current test, and the depth of scratches and cracks is further measured by an ultrasonic test. This ultrasonic flaw detection test is performed by remote control of the test robot after the drain work of the primary coolant in the inlet side water chamber 131 is performed.

  In the inspection of the welded part 152, when a defect that requires repair is found, the welded part 152 is repaired. In this repair, first, a sump observation is performed (step S1). In the sump observation, an operator enters the inside of the inlet-side water chamber 131 from the manhole 137, polishes and etches the surface of the defective portion, and transfers the metal surface structure to the replica film. In this sump observation, since the worker enters the inside of the inlet-side water chamber 131, in order to reduce the radiation dose irradiated to the worker, the inside of the primary coolant pipe 150 is blocked before the observation. In addition, a shield is installed along the inner wall of the inlet-side water chamber 131. In this sump observation, the length of the flaw on the surface of the defective portion may be confirmed by a penetrant flaw detection test. Then, after the observation of the sump, each shield is removed.

  Next, the elbow pipe 151 is cut (step S2). The elbow pipe 151 is removed by cutting the welded portion 152 with the inlet nozzle 135 and the welded portion 153 with the primary coolant pipe 150.

  Next, decontamination of the inside of the inlet nozzle 135 and the inside of the primary coolant pipe 150 is performed (step S3). The decontamination is performed by blasting in which the granular projection material collides with the site to be decontaminated from the opening on the inlet nozzle 135 side and the opening on the primary coolant pipe 150 side that are generated when the elbow pipe 151 is removed. When decontamination is performed, a shield (not shown) is installed so as to block the part of the inlet side water chamber 131 reaching the inlet nozzle 135 and the inside of the primary coolant pipe 150. Reduce the radiation dose to workers performing decontamination. The removed elbow pipe 151 is also decontaminated.

  Next, buttering welding is performed on the opening peripheral end surface on the inlet nozzle 135 side (step S4). That is, a buttering layer serving as a joint surface with the elbow pipe 151 to be welded later is formed on the peripheral edge surface of the opening on the inlet nozzle 135 side by overlay welding. In the step S4, the shield installed in step S3 is left installed.

  Next, annealing is performed on the part subjected to buttering welding (step S5). In the step S5, the shield installed in step S3 is left installed.

  Next, a groove is formed (step S6). The part forming the groove includes an opening peripheral end surface (battering welded portion) on the inlet nozzle 135 side, an opening peripheral end surface on the primary coolant pipe 150 side, and an elbow pipe 151 (even if removed at step S2). These may be the peripheral end surfaces of the two openings, which are welded to each other. In the step S6, the shield installed in step S3 is left installed. This shield is removed when the formation of the groove is completed.

  Next, the elbow pipe 151 is welded to the inlet nozzle stand 135 side and the primary coolant pipe 150 side (step S7). That is, the inlet nozzle 135 and the primary coolant pipe 150 are connected via the elbow pipe 151.

  Next, an urgent inspection is performed on the portion welded in step S7 (step S8). In the uranami inspection, the radiation irradiated to the welded portion (corresponding to the welded portions 152 and 153) is transferred to the film to inspect whether the welded portion is sound. In this uranami inspection, if there is a protrusion protruding on the inner wall surface 150a side of the primary coolant pipe 150, the inspection cannot be determined. That is, it can be seen whether or not there is a protrusion on the lumpy portion.

  Finally, when a protrusion is found in the undulating part by the urami inspection (step S8: Yes), the operator enters the entrance-side water chamber 131 from the manhole 137 and cuts out the protruding part of the undulating part ( Step S9). In the process of excision of the protrusions of the undulating part, since the operator enters the inlet side water chamber 131 or the primary coolant pipe 150, before the excision is performed in order to reduce the radiation dose irradiated to the operator. In addition, a shielding body (shielding body described later) is installed so as to block the inside of the primary coolant pipe 150, and a shielding body (shielding body described later) is installed along the inner wall of the inlet-side water chamber 131. Then, after the removal of the protrusions of the lumpy part is completed, each shield is removed.

  Here, the shielding apparatus used for the said work in a structure is demonstrated. FIG. 4 is a schematic diagram showing a shielding container of the shielding device according to the embodiment of the present invention, FIG. 5 is a schematic diagram showing the shielding device, and FIGS. 6 to 10 are diagrams showing an installation process of the shielding member, FIGS. 11-13 is a figure which shows the removal process of a shielding member, FIGS. 14-18 is a figure which shows the other shielding member concerning embodiment of this invention.

  As shown in FIGS. 4 and 5, the shielding device 1 includes a shielding container 2 and an operation unit 3. As shown in FIG. 4, the shielding container 2 is a so-called balloon in which a sealed area is formed inside a flexible and stretchable outer skin 21 made of urethane rubber or the like in a bag shape by high frequency welding. It constitutes. The shielding container 2 is a container in which an inner sealed area is filled with a fluid and the outer skin 21 swells. In the swelled state (shown by a solid line in FIG. 4), the inside of the structure (here, the primary coolant pipe 150) A shield along the circumference. In addition, the deflated form of the state which the fluid was discharged | emitted from the sealed area inside the shielding container 2 is shown with the dashed-two dotted line in FIG.

  One end of the air pipe 22 is fixed to a part of the outer skin 21 of the shielding container 2 so as to communicate with the inside of the shielding container 2. The air feed tube 22 has flexibility, and a connector 23 such as a coupler is provided at the other end. The air feed tube 22 is formed to be transparent so that the inside of the tube can be seen. In addition, plate-shaped holding members 24 are provided on the outer periphery of both ends of the shielding container 2 so as to face each other. Each holding member 24 is fixed to both ends of a cylindrical member 25 inserted into the shielding container 2. A plurality of holes (not shown) are formed in the cylinder member 25 so that the inside of the cylinder communicates with the inside of the shielding container 2. The cylindrical member 25 has one end closed, the other end penetrates the holding member 24 and communicates the inside of the cylinder to the outside of the shielding container 2, and the other end is fed with water. One end of the tube 26 is fixed. The water pipe 26 has flexibility, and a connector 23 such as a coupler is provided at the other end. Further, a U-shaped handle 27 is provided on the outer surface of the holding member 24 fixed to one end of the cylindrical member 25. Further, on the outer surface of the holding member 24 fixed to the other end portion of the cylindrical member 25, a locking portion 28 having a shape in which both ends of the bar member are fixed by plate members attached to the holding member 24 is provided. .

  The operation unit 3 includes an air supply / exhaust means 4, a water supply / drainage means 5, and a monitoring means 6. The air supply / exhaust means 4 is for supplying or exhausting air to or from the shielding container 2. The air supply / exhaust means 4 has an air supply main pipe 41 connected between an air compressor (not shown) outside the operation unit 3 and the air supply pipe 22 of the shielding container 2. That is, one end of the air feed main pipe 41 is connected to the air compressor and the other end is connected to the air feed pipe 22. The air supply main pipe 41 includes a pressure regulator 41a, an air supply source valve 41b, an exhaust valve 41c, and an air supply valve 41d from one end connected to the air compressor to the other end connected to the air supply pipe 22. It is provided sequentially toward the side. Further, an air pressure gauge 41e is connected to the air supply main pipe 41 between the exhaust valve 41c and the air supply valve 41d.

  The air supply / exhaust means 4 supplies air to the shielding container 2. First, the supply air source valve 41b is opened, and the exhaust valve 41c and the supply valve 41d are closed. Next, the pressure adjuster 41a adjusts the pressure value indicated by the air pressure gauge 41e to a predetermined pressure value. Next, the air supply valve 41d is opened. Thereby, the air is supplied into the shielding container 2. At this time, since the air pressure decreases, the pressure regulator 41a adjusts so that the pressure value indicated by the air pressure gauge 41e becomes the pressure value set above. Next, when the pressure value indicated by the air pressure gauge 41e gradually increases from the set pressure value, the air is filled in the shielding container 2 at a desired pressure value, so the air supply valve 41d is closed. To do.

  On the other hand, when exhausting from the shielding container 2, the supply source valve 41b is closed, and the exhaust valve 41c and the supply valve 41d are opened.

  The water supply / drainage means 5 is for supplying or draining water to the shielding container 2. The water supply / drainage means 5 has a water supply main pipe 52 connected between a water supply tank 51 disposed in the operation unit 3 and the water supply pipe 26 of the shielding container 2. That is, the water supply main pipe 52 has one end connected to the water supply tank 51 and the other end connected to the water supply pipe 26. The water supply main pipe 52 includes a pump water supply valve 52a, a water supply pump 52b, a water supply adjustment valve 52c, and a water supply valve 52d from one end side connected to the water supply tank 51 to the other end side connected to the water supply pipe 26. It is provided sequentially. Further, a water pressure gauge 52e is connected to the water supply main pipe 52 between a water supply adjustment valve 52c and a water supply valve 52d. Further, the water supply main pipe 52 is provided with a drain valve 52f between the water supply tank 51 and the pump water supply valve 52a. The water main pipe 52 is connected to a bypass pipe 53 that connects the upstream side and the downstream side of the water supply pump 52b. The bypass pipe 53 is provided with a bypass valve 53a. In addition, a pressure relief pipe 54 is connected to the water main pipe 52 between a portion where the bypass pipe 53 is connected on the upstream side of the water supply pump 52b and the water supply adjustment valve 52c. One end of the pressure relief pipe 54 is connected to the water main pipe 52, and the other end reaches the water supply tank 51. The pressure relief pipe 54 is provided with a pressure relief valve 54 a and a pressure relief valve 54 b from the side close to the water feed main pipe 52. The opening degree of the pressure relief valve 54b is adjusted by the pressure relief setting device 54c. The pressure relief setter 54c is provided with a pressure detector 54d that detects the pressure at the same location as the water pressure gauge 52e (between the water supply adjustment valve 52c and the water supply valve 52d of the water main pipe 52). Further, a drain pipe 55 is connected to the water main pipe 52 on the upstream side of the water supply valve 52d. The drain pipe 55 has one end connected to the water main pipe 52 and the other end reaching the drain tank 56. The drain pipe 55 is provided with a drain valve 55 a and a drain pump 55 b from the side close to the water main pipe 52. The drainage pump 55b is provided with a drainage pump drive pipe 57 connected between the pressure regulator 41a of the air supply main pipe 41 in the air supply / exhaust means 4 and the air supply source valve 41b. The drain pump drive pipe 57 is provided with a drain pump drive valve 57a.

  The water supply pump 52b is supplied with power via a water supply pump switch 58. The drain pump 55b is an air pump, and is driven by supplying compressed air from an air compressor (not shown) outside the operation unit 3 via a drain pump drive pipe 57. The water supply tank 51 is provided with a water surface detector 51a, and is configured so that water is automatically supplied to the water supply tank 51 when the water surface detector 51a detects a predetermined water level below the water surface. Yes.

  Water is supplied to the shielding container 2 by the water supply / drainage means 5. Here, a description will be given of water supply from a state in which the inside of the shielding container 2 is filled with air at a desired pressure value by the air supply / exhaust means 4, that is, a case where the air inside the shielding container 2 is replaced with water. First, the air supply source valve 41b of the air supply / exhaust means 4 is closed, and the exhaust valve 41c and the air supply valve 41d are opened. Next, the water supply valve 52d, the drain valve 52f, the drain valve 55a, and the drain pump drive valve 57a of the water supply / drainage means 5 are closed, and the pump water supply valve 52a, the water supply adjustment valve 52c, the bypass valve 53a, and the pressure relief valve 54a are opened. Put it in a state. Next, it is confirmed that water is stored in the water supply tank 51 at a predetermined water level, and the water supply pump switch 58 is turned on. Next, the water supply valve 52d is opened. Thereby, water is supplied into the shielding container 2. At this time, the water supply adjustment valve 52c is adjusted so that the pressure value indicated by the water pressure gauge 52e becomes a predetermined pressure value. Further, when the pressure value is less than the desired pressure value, the bypass valve 53a is gradually closed and adjusted so as to become a predetermined pressure value.

  Check the water head pressure during this water supply. First, after a few minutes (for example, about 3 minutes) have elapsed since the start of water supply, the water main pipe 52 is filled and the water supply adjustment valve 52c is closed. Next, the pressure value indicated by the water pressure gauge 52e is recorded. This pressure value becomes the water head pressure. Then, the water supply adjustment valve 52c is gradually opened, and adjustment is made by the bypass valve 53a so as to obtain a pressure value obtained by adding a predetermined pressure value to the water head pressure, and water supply is resumed.

  Then, the water supply is continued, and when the water comes out from the inside of the shielding container 2 to the air feeding tube 22, the water supply is completed. At this time, the water supply valve 52d of the water supply / drainage means 5 is closed, and the exhaust valve 41c and the air supply valve 41d of the air supply / exhaust means 4 are closed. Finally, the water supply pump switch 58 is turned off.

  On the other hand, it drains from the shielding container 2. First, the air supply source valve 41b, the exhaust valve 41c and the air supply valve 41d of the air supply / exhaust means 4 are closed, and the pump water supply valve 52a, the water supply adjustment valve 52c, the water supply valve 52d, the drain valve 52f, the bypass of the water supply / drainage means 5 are bypassed. The valve 53a, the pressure relief valve 54a, and the drain valve 55a are closed. Next, the pressure adjuster 41a of the air supply / exhaust means 4 is adjusted so that the pressure value indicated by the air pressure gauge 41e becomes a predetermined pressure value. Next, the drain pump drive valve 57a is opened. Thereby, the drainage pump 55b is driven and drained from the inside of the shielding container 2 to the drainage tank 56. The drainage is completed when the operation sound of the drainage pump 55b changes. At this time, the drain pump drive valve 57a is closed and the drain pump 55b is stopped. Next, the air supply source valve 41b and the air supply valve 41d of the air supply / exhaust means 4 are opened to supply air into the shielding container 2 for a few seconds, and then the air supply source valve 41b and the air supply valve 41d are closed. Put it in a state. This operation is for preventing the inside of the shielding container 2 from coming into close contact. Finally, the pressure regulator 41a of the air supply / exhaust means 4 is operated to stop the supply of air.

  The monitoring means 6 is for monitoring the air supply state, water supply state, and drainage state of the shielding container 2, and has a camera 61 and a monitor 62. The camera 61 is provided with an illumination 61a. Power is supplied to the camera 61 and the monitor 62, respectively. In addition, the camera 61 is connected to a monitor 62, and the video taken by the camera 61 can be confirmed on the monitor 62.

  In the operation unit 3 described above, the air supply / exhaust means 4, the water supply / drainage means 5 (excluding the drainage tank 56), and the monitor 62 of the monitoring means 6 are arranged in an integral frame 7. The frame 7 is provided with casters 71 so that the frame 7 can be easily moved.

  An in-structure work method in which the shielding apparatus 1 configured in this way is applied to maintenance work for the inlet nozzle 135 of the steam generator 130 in the structure of the nuclear power plant 100 described above will be described.

  In repairing the welded portion 152 between the inlet pedestal 135 and the elbow pipe 151, in the step of removing the projection of the undulating portion in step S <b> 9, an operator can enter the inside of the inlet side water chamber 131 and the primary coolant pipe 150 from the manhole 137. The protrusions generated in the stagnation parts of the welded part 152 and the welded part 153 are cut off. In this process, since the worker enters the entrance-side water chamber 131 and the primary coolant pipe 150, a shield for reducing the radiation dose irradiated to the worker is installed.

  First, a description will be given of the removal of protrusions when protrusions are formed at the undulating portion of the welded portion 153 between the primary coolant pipe 150 and the elbow pipe 151.

  First, the shielding device 1 is set. Specifically, as shown in FIG. 5, the air feed pipe 22 of the shielding container 2 is connected to the air feed main pipe 41 of the air supply / exhaust means 4, and the water feed pipe 26 is connected to the water feed main pipe 52 of the water supply / drainage means 5. At the same time, the camera 61 of the monitoring means 6 is connected to the monitor 62 and the power line. Then, the compressed air is supplied from the air compressor (not shown) to the air main pipe 41 of the air supply / exhaust means 4, the water is supplied to the water supply tank 51 of the water supply / drainage means 5, and the water supply pump 52b. In such a state, power is supplied through the water supply pump switch 58.

  Next, the operator brings the shielding container 2 with the outer skin 21 deflated from the manhole 137 into the inlet-side water chamber 131, and the shielding container 2 passes through the elbow pipe 151 from the inlet nozzle 135 into the primary coolant pipe 150. Slide down. Here, the shielding container 2 can be easily carried by grasping the handle 27 and the locking portion 28. When the position and orientation of the shielding container 2 slid down inside the primary coolant pipe 150 are not appropriate, the operator adjusts the position and orientation of the shielding container 2 from the inlet side water chamber 131 by the guide member 8 (FIG. 6).

  The guide member 8 is a longitudinal bar, and the length thereof is provided so that the length can be adjusted. At the tip of the guide member 8, an upward U-shaped hook 81 and a lock pin 82 for opening and closing the opening portion of the hook 81 are provided. The lock pin 82 is opened and closed on the proximal end side of the guide member 8 held by the operator. Then, the lock pin 82 is opened and the hook 81 is hooked on the locking portion 28 of the shielding container 2, and the lock pin 82 is closed and the hook 81 is locked on the locking portion 28. For this reason, it becomes possible for an operator to adjust the position and orientation of the shielding container 2 without entering the primary coolant pipe 150 from the inlet-side water chamber 131 (see FIGS. 7A and 7B). .

  In addition, when the shielding container 2 in a form in which the outer skin 21 is deflated is disposed in the primary coolant pipe 150, each holding member 24 contacts the inner bottom surface of the primary coolant pipe 150. That is, the holding member 24 forms a leg for arranging the shielding container 2 inside the primary coolant pipe 150. For this reason, the position and orientation adjusted inside the primary coolant pipe 150 can be maintained for the shielding container 2 before the outer skin 21 is expanded.

  Next, the operator brings the camera 61 of the monitoring means 6 from the manhole 137 into the inlet side water chamber 131 and installs the camera 61 at a position where the shielding container 2 can be seen from the inlet nozzle 135. And an operator comes out from the entrance side water chamber 131, and the inside of a structure (inlet side water chamber 131 and the primary coolant pipe | tube 150) is made into an unattended state. In addition, the state of the shielding container 2 is photographed by the camera 61 in the unmanned structure. And the image | video image | photographed with the camera 61 is monitored with the monitor 62 outside a structure (refer FIG. 8).

  Next, air is supplied into the shielding container 2 by the air supply / exhaust means 4. When it is confirmed on the image of the monitor 62 that the position and orientation of the shielding container 2 have changed due to the expansion of the outer skin 21 during this air supply, the operator enters the inside of the inlet side water chamber 131 from the manhole 137, The position and orientation of the shielding container 2 are adjusted by the guide member 8 described above. Thus, the state of the shielding container 2 is monitored by the monitor 62 outside the structure, and the inside of the shielding container 2 is filled with air while making the position and orientation of the shielding container 2 appropriate (see FIG. 9).

  Next, water is supplied into the shielding container 2 by the water supply / drainage means 5. As described above, this water supply replaces the air previously filled in the shielding container 2 with water. Then, the state of the shielding container 2 is monitored by the monitor 62 outside the structure, and the inside of the shielding container 2 is filled with water (water has flowed from the inside of the shielding container 2 to the air feeding tube 22). Confirm that the water supply is complete. In this way, by replacing the air previously filled in the shielding container 2 with water, the position and orientation of the shielding container 2 are hardly changed from the state filled with air. Can be filled (see FIG. 9).

  As shown in FIG. 9, in the form in which the inside of the shielding container 2 is filled with air or water, that is, in the form in which the outer skin 21 swells, the holding members 24 sandwich the outer skin 21 in which the holding members 24 swell, and the outer skin 21 between them. Form a frame that retains its shape. For this reason, the shape of the shielding container 2 in which the outer skin 21 swells can be maintained.

  Next, an operator enters the entrance-side water chamber 131 from the manhole 137 and removes the camera 61. Further, the air feed pipe 22 of the shielding container 2 is removed from the air feed main pipe 41 of the air supply / exhaust means 4 at the joint 23, and the water feed pipe 26 is removed from the water feed main pipe 52 of the water supply / drainage means 5 at the joint 23. . Then, the air feeding pipe 22 and the water feeding pipe 26 are slid down to the position of the shielding container 2 (see FIG. 10).

  In this way, the shielding body filled with water inside the shielding container 2 is installed inside the primary coolant pipe 150. Thereafter, the operator enters the elbow pipe 151 and cuts out the protrusion of the stagnation part in the welded part 153. At this time, the amount of radiation irradiated to the operator from the primary coolant pipe 150 side is reduced by the shielding body filled with water inside the shielding container 2, so that the work can be performed safely.

  When the excision of the projection of the undulating portion in the welded portion 153 is completed, the operator enters the inside of the inlet side water chamber 131 from the manhole 137, and the guide pipe 8 moves the air feeding pipe 22 and the water feeding pipe 26 of the shielding container 2. The primary coolant pipe 150 is pulled up to the inlet side water chamber 131 (see FIG. 11).

  An L-shaped hook 83 is provided at the tip of the guide member 8. On the other hand, a pulling rope 29 is provided in the shielding container 2, and a ring 29 a is formed at the tip of the pulling rope 29. The pulling rope 29 is bundled together with the air feeding pipe 22 and the water feeding pipe 26. 11 and 12, the hook 83 of the guide member 8 is hooked on the ring 29a of the pull-up rope 29 and pulled up as it is, so that the air feed pipe 22 and the water feed pipe 26 enter the inlet together with the pull-up rope 29. The water is raised to the side water chamber 131.

  Next, the air feed pipe 22 of the shielding container 2 is connected to the air feed main pipe 41 of the air supply / exhaust means 4, and the water feed pipe 26 is connected to the water feed main pipe 52 of the water supply / drainage means 5. Further, the camera 61 of the monitoring means 6 is installed at a position where the shielding container 2 can be seen from the inlet nozzle 135. And an operator comes out from the entrance side water chamber 131, and the inside of a structure (inlet side water chamber 131 and the primary coolant pipe | tube 150) is made into an unattended state. In addition, the state of the shielding container 2 is photographed by the camera 61 in the unmanned structure. And the image | video image | photographed with the camera 61 is monitored with the monitor 62 outside a structure (refer FIG. 9).

  Next, the inside of the shielding container 2 is drained by the water supply / drainage means 5. The state of the shielding container 2 is monitored by the monitor 62 outside the structure until drainage inside the shielding container 2 is completed.

  Next, an operator enters the entrance-side water chamber 131 from the manhole 137 and removes the camera 61. Further, by holding the ring 29a of the pull-up rope 29 that has been pulled up to the inlet-side water chamber 131 side by the guide member 8 in advance and pulling the pull-up rope 29, the shield container 2 in a deflated form is brought into the inlet-side water. Raise to chamber 131 (see FIG. 13). Finally, the shielding container 2 is carried out from the manhole 137 to the outside of the inlet side water chamber 131. In this way, the shielding container 2 is removed.

  Secondly, a description will be given of the removal of the protrusion when the protrusion is generated in the stagnation part of the welded part 152 between the inlet nozzle 135 and the elbow pipe 151. It should be noted that, in the operation of removing the projection of the stagnation portion in the welded portion 152, the operation does not enter the primary coolant pipe 150 as in the operation of slashing the projection of the undulating portion in the welded portion 153. I do. For this reason, in the operation of removing the projection of the stagnation part in the welded part 152, the shielding container 9 different from the shielding container 2 used for the work of slashing the projection of the stagnation part in the welded part 153 is used. Furthermore, the support member 10 for supporting the shielding container 9 is newly used in the operation of cutting out the protrusion of the undulating portion in the welded portion 152.

  As shown in FIGS. 14 to 18, the support member 10 forms a frame made of stainless steel pipe material disposed so as to cover the opening 135 a of the inlet nozzle 135 inside the inlet-side water chamber 131. A desired working area is defined around the opening 135 a of the inlet nozzle 135. The support member 10 is composed of a downward U-shaped enclosure 10a arranged in parallel across the opening 135a of the inlet nozzle 135, and a connecting part 10b that connects the upper part of the enclosure 10a. The surrounding portion 10a and the connecting portion 10b are divided into a plurality of parts, and are brought into the inlet-side water chamber 131 from the manhole 137 by an operator.

  Further, since the support member 10 is installed inside the inlet-side water chamber 131, the base portion 11 is disposed at the bottom of the inlet-side water chamber 131. As shown in FIGS. 14 and 15, the base part 11 is laid by being fitted into the bottom part of the inlet-side water chamber 131 with the opening 135 a of the inlet nozzle 135 and the manhole 137 open. The base portion 11 is formed with an attachment hole 11a through which each end portion of the surrounding portion 10a of the support member 10 is inserted. Moreover, the base part 11 is comprised by the member which has the intensity | strength which supports the supporting member 10 inserted in the attachment hole 11a, for example, an aluminum board, and is a member which shields a radiation, for example, tungsten powder and resin material A shielding member in which a plurality of tungsten sheets formed in this manner are stacked is included. Such a base part 11 is divided into a plurality of parts so as to be brought into the inlet side water chamber 131 from the manhole 137 by an operator. In addition, about the base part 11 in which the attachment hole 11a is not formed, it is comprised only with the shielding member.

  Similarly to the shielding container 2 described above, the shielding container 9 is a so-called sealed area in which a flexible and stretchable outer skin 21 made of urethane rubber or the like is formed into a bag shape by high frequency welding and covered. It constitutes a balloon. The shielding container 9 is interposed between the support member 10 installed inside the inlet-side water chamber 131 and the inner wall surface 131a of the inlet-side water chamber 131, and is divided into a plurality of parts. In this Embodiment, in FIG. 16-18 which shows the form which the inside was filled with the fluid and the outer skin swelled, the 1st shielding container 9a arrange | positioned in the innermost part of the inlet side water chamber 131 furthest from the manhole 137 is shown. (See FIGS. 16 and 18), the second shielding container 9b (see FIGS. 16 and 17) disposed in the arc-shaped side region of the inlet-side water chamber 131, and the partition plate 134 of the inlet-side water chamber 131. A third shielding container 9c (see FIGS. 16 and 17) disposed on the side area on the side, and a fourth shielding container 9d (see FIGS. 16 to 18) disposed in the upper area of the inlet-side water chamber 131; Are divided and formed. Moreover, a partition (not shown) that divides the sealed area into a plurality of rooms is provided on a thing that shields a relatively large area, such as the fourth shielding container 9d, so that the swollen shape does not deform. . This partition is made of the same member (urethane rubber or the like) as the outer skin, and has a plurality of holes so as to communicate with each room. Although not shown in the drawing, each shielding container 9 (9a, 9b, 9c, 9d) is provided with an air feeding pipe 22 and a water feeding pipe 26 as in the shielding container 2, and the air feeding pipe 22 The water supply pipe 26 is provided in the air supply main pipe 41 of the air supply / exhaust means 4 so as to be connectable to the water supply main pipe 52 of the water supply / drainage means 5 via the connector 23.

  The shielding container 9 (9a, 9b, 9c, 9d) is installed inside the inlet-side water chamber 131. After the support member 10 is installed inside the inlet-side water chamber 131 as described above, first, the deflated first shielding container 9a is placed between the support member 10 and the inner wall surface 131a of the inlet-side water chamber 131. Place in position and supply air to inflate. Next, the deflated second shielding container 9b is disposed at a predetermined position between the support member 10 and the inner wall surface 131a of the inlet-side water chamber 131, and is supplied with air to be inflated. Next, the deflated third shielding container 9c is disposed at a predetermined position between the support member 10 and the inner wall surface 131a of the inlet-side water chamber 131 and is supplied with air to be inflated. Next, water is supplied and water is replaced with water in the order of the first shielding container 9a, the second shielding container 9b, and the third shielding container 9c. Next, the deflated fourth shielding container 9d is disposed at a predetermined position between the support member 10 and the inner wall surface 131a of the inlet-side water chamber 131, and is supplied with air to be inflated. Replace with water.

  In this way, the shielding body in which the inside of the shielding container 9 (9a, 9b, 9c, 9d) is filled with water is combined inside the inlet-side water chamber 131, and the opening of the inlet nozzle 135 serving as a work area. A shield covering 135a is formed. Here, if necessary, a shielding member made of a tungsten sheet may be hung on the outer periphery of the support member 10 to increase the radiation shielding effect. Thereafter, the operator enters the opening 135 a of the inlet nozzle 135 and cuts out the protrusion of the stagnation portion in the welded portion 152. At this time, since the shielding body 9 (9a, 9b, 9c, 9d) is filled with water, the radiation dose irradiated to the operator from the inner wall side of the inlet side water chamber 131 is reduced. Work can be performed safely.

  When excision of the projection of the undulating portion in the welded portion 152 is completed, the shielding container 9 (9a, 9b, 9c, 9d) is removed to the outside of the inlet side water chamber 131. First, drainage is performed from the inside of the fourth shielding container 9d, and the fourth shielding container 9d that has been drained is carried out from the manhole 137 to the outside of the inlet-side water chamber 131. Next, the inside of the third shielding container 9c is drained, and the third shielding container 9c that has been drained is carried out from the manhole 137 to the outside of the inlet-side water chamber 131. Next, the second shielding container 9b is drained from the inside, and the second shielding container 9b that has been drained is carried out of the manhole 137 to the outside of the inlet-side water chamber 131. Next, the first shielding container 9a is drained from the inside, and the first shielding container 9a that has been drained is carried out of the manhole 137 to the outside of the inlet-side water chamber 131. Next, the supporting member 10 is disassembled and carried out of the manhole 137 to the outside of the inlet side water chamber 131. Finally, the base 11 is disassembled and carried out of the manhole 137 to the outside of the inlet side water chamber 131.

  In addition, also in the process of installing the shielding body when cutting out the projection of the undulating portion in the welded part 152, the state of the shielding container 9 (9a, 9b, 9c, 9d) is photographed with the camera 61, and the outside of the structure Monitoring is performed by the monitor 62.

  The shielding device to which the shielding container 9 (9a, 9b, 9c, 9d) is applied is installed along the inner wall of the inlet side water chamber 131 in the sump observation (step S1) when repairing the welded portion 152. It is also applied as a shield.

  As described above, the in-structure work method according to the present embodiment includes the shielding containers 2 and 9 that are filled with a fluid in a sealed area covered with a flexible and stretchable outer skin, and the outer skin swells. A step of disposing the structure in a desired position inside the structure (primary coolant pipe 150 or the inlet side water chamber 131), and a step of supplying and inflating the shielding containers 2 and 9 Next, the shielding containers 2 and 9 are exhausted while supplying water, and the shielding containers 2 and 9 filled with water are used to form a wall-shaped shielding body that covers a desired position in the structure and shields radiation. And a step of performing an operation in a region where radiation is shielded by the shield.

  Further, the shielding device 1 of the present embodiment includes a shielding container 2 and 9 in which a sealed area is formed inside by a flexible and stretchable outer skin, and the sealed area is filled with fluid and the outer skin swells, The air supply / exhaust means 4 for supplying or exhausting air to / from the shielding containers 2 and 9 and the water supply / drainage means 5 for supplying or discharging water to the shielding containers 2 and 9 are provided.

  For this reason, it becomes possible to reduce the radiation dose irradiated to the worker who performs work in a structure easily, and to work safely. Moreover, since the shield is once supplied to the inside of the shielding containers 2 and 9 and then exhausted while being supplied with water, the position and orientation in the structure can be adjusted at the time of supply and the shape is filled with water. Is stable. For this reason, it becomes possible to apply the shielding body filled with water inside.

  Moreover, the shielding apparatus 1 of this Embodiment is provided with the monitoring means 6 which monitors the state which the shielding containers 2 and 9 arrange | positioned inside the structure swell or the state which defers outside. For this reason, it becomes possible for an operator to monitor the state of the shielding containers 2 and 9 without entering the structure.

  Moreover, in the shielding apparatus 1 of this Embodiment, when the shielding containers 2 and 9 are arranged at predetermined positions inside the structure, the inner peripheral shape of the structure is filled when the sealed area is filled with fluid and swells. It suffices if it is formed so as to follow. On the other hand, not only this but the shielding containers 2 and 9 may be previously formed in the external shape which meets the inner peripheral shape of a structure in the state which filled the fluid with the sealed area and expanded. According to such a configuration, the shielding containers 2 and 9 swell in accordance with the inner peripheral shape of the structure and appropriately close the inside of the structure, so that the radiation shielding effect can be improved and the radiation dose can be further reduced. Become.

  In addition, the shielding device of the present embodiment includes a support member 10 that covers and defines a desired work area inside the structure and supports the shielding container 9 on the outer periphery thereof. For this reason, it is possible to apply the shielding container 9 when configuring a shielding body that covers the work area.

  Further, the shielding container 9 is divided into a plurality of parts, which are combined to form one shielding body. For this reason, when the area | region which arrange | positions a shield is comparatively wide, it becomes possible to apply the shielding container 9. FIG.

  In the embodiment described above, water is supplied to the water supply, but this water may be pure water or water mixed with boric acid or the like in order to improve the radiation shielding ability.

  In the above-described embodiment, the in-structure work method and the shielding device related to the maintenance of the inlet nozzle 135 in the steam generator 130 of the nuclear power plant 100 have been described. In addition to the outlet nozzle in the steam generator 130, the present invention can be applied to maintenance of the nozzle of the nuclear power plant 100.

  As described above, the in-structure operation method and the shielding apparatus according to the present invention make it possible to easily reduce the radiation dose irradiated to the worker while applying the shielding body in which the container is filled with water, thereby making the work safe. Suitable for doing.

It is explanatory drawing which shows the structure of the steam generator of a nuclear power plant. It is the schematic which shows the nozzle part of the steam generator shown in FIG. It is a flowchart which shows the maintenance work process of the steam generator nozzle including the work method in a structure concerning embodiment of this invention. It is the schematic which shows the shielding container of the shielding apparatus concerning embodiment of this invention. It is the schematic which shows the shielding apparatus. It is a figure which shows the installation process of a shielding member. It is a figure which shows the installation process of a shielding member. It is a figure which shows the installation process of a shielding member. It is a figure which shows the installation process of a shielding member. It is a figure which shows the installation process of a shielding member. It is a figure which shows the removal process of a shielding member. It is a figure which shows the removal process of a shielding member. It is a figure which shows the removal process of a shielding member. It is a figure which shows the other shielding member concerning embodiment of this invention. It is a figure which shows the other shielding member concerning embodiment of this invention. It is a figure which shows the other shielding member concerning embodiment of this invention. It is a figure which shows the other shielding member concerning embodiment of this invention. It is a figure which shows the other shielding member concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shielding device 2 Shielding container 21 Outer skin 22 Air supply pipe 23 Joint 24 Holding member 25 Cylinder member 26 Water supply pipe 27 Handle 28 Locking part 29 Lifting rope 29a Ring 3 Operation part 4 Supply / exhaust means 41 Air supply main pipe 41a Pressure Adjuster 41b Supply valve 41c Exhaust valve 41d Supply valve 41e Air pressure gauge 5 Supply / drainage means 51 Supply tank 51a Water surface detector 52 Water supply main pipe 52a Pump supply valve 52b Supply pump 52c Supply adjustment valve 52d Supply valve 52e Water pressure gauge 52f Drain valve 53 Bypass pipe 53a Bypass valve 54 Pressure relief pipe 54a Pressure relief valve 54b Pressure relief valve 54c Pressure relief setter 54d Pressure detector 55 Drain pipe 55a Drain valve 55b Drain pump 56 Drain tank 57 Drain pump drive pipe 57a Drain Pump drive valve 58 Water supply pump switch 6 Monitoring means 61 Turtle La 61a Illumination 62 Monitor 7 Frame 71 Caster 8 Guide member 81 Hook 82 Lock pin 83 Hook 9 (9a, 9b, 9c, 9d) Shielding container 10 Support member 10a Enclosure 10b Connecting portion 11 Base portion 11a Mounting hole 100 Nuclear power plant 110 reactor vessel 120 pressurizer 130 steam generator 131 inlet side water chamber 131a inner wall surface 132 heat transfer tube 133 outlet side water chamber 134 partition plate 135 inlet nozzle 135a opening 137 manhole 140 pump 150 primary coolant pipe 150a inner wall surface 151 elbow Pipe 152,152 Welded part

Claims (7)

A work method in a structure for performing work in a structure of a nuclear power plant,
Arranging a shielding container in which a sealed area covered with a flexible outer skin is filled with a fluid to expand the outer skin at a desired position inside the structure in a form in which the outer skin is deflated;
Next, supplying air to the shielding container and inflating;
Next, a step of forming a wall-shaped shielding body that exhausts while supplying water to the shielding container, covers a desired position in the structure by the shielding container filled with water, and shields radiation;
Next, working in an area where radiation is shielded by the shield,
A method for working in a structure, comprising: A shielding device for shielding radiation irradiated to a work area in a structure of a nuclear power plant,
A sealed container in which a sealed area covered with a flexible outer skin is filled with fluid and the outer skin expands;
Air supply / exhaust means for supplying or exhausting air to or from the shielding container;
Water supply / drainage means for supplying or draining water to the shielding container;
A shielding device comprising:   The shielding apparatus according to claim 2, further comprising a monitoring unit configured to monitor an outside of the structure in a state where the shielding container disposed inside the structure is inflated or deflated.   The said shielding container was equipped with the holding member which makes the leg arrange | positioned inside the said structure with the said shielding container deflated, and made | forms the frame which hold | maintains the shape which the said shielding container expanded. 2. The shielding device according to 2 or 3.   The said shielding container is previously formed in the external shape in alignment with the inner peripheral shape of the said structure in the state which the fluid was filled in the said sealing area and the said outer shell expanded. The shielding apparatus as described in one.   6. The apparatus according to claim 2, further comprising a support member configured to cover a desired work area inside the structure and to support the shielding container at an outer periphery thereof. Shielding device.   The shielding apparatus according to claim 6, wherein the shielding container is divided into a plurality of parts and is combined to form one shielding body.

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