JP2014190893A - Method and apparatus for internally inspecting reactor pressure vessel - Google Patents

Abstract

The inside of a reactor pressure vessel capable of efficiently conducting investigation work inside an RPV even if it is difficult to carry out normal investigation and maintenance work procedures due to the occurrence of an accident at a nuclear reactor facility The survey method is provided.
Means for solving the problems of the present invention are a method for investigating the inside of a reactor pressure vessel in a nuclear power plant, a step of penetrating a structure up to the inside of the reactor pressure vessel, and the penetration The method includes the steps of securing an access path in the processed structure and inserting a device using the access path.
[Selection] Figure 1

Description

  The present invention relates to an investigation method and apparatus for grasping the environment inside a reactor pressure vessel from the outside of the reactor pressure vessel.

  In a regular periodic inspection at the reactor facility, the shield plug, the containment vessel lid, and the reactor pressure vessel lid are sequentially removed, and the reactor well located at the top of the reactor pressure vessel is filled with water. The equipment inside the reactor is taken out sequentially, and the inside of the reactor pressure vessel (RPV: Reactor Pressure Vessel) is investigated and maintained. Patent Document 1 describes a method of shortening the maintenance work inside the RPV by removing the structure and then installing the guide pipe in the furnace and carrying the maintenance device into the RPV through the guide pipe. ing.

WO02 / 011151

  In the unlikely event that an emergency situation occurs that causes the loss of the overall function of the reactor building, normal investigation and maintenance work procedures inside the RPV will be carried out due to reasons such as the removal device of these structures not working. It may be difficult to do this. When such a situation is reached, it may take a long time to investigate the inside of the RPV.

  The present invention provides a reactor pressure vessel capable of efficiently conducting investigation work inside the RPV even when it is difficult to carry out normal investigation and maintenance work procedures due to the occurrence of an accident at the reactor facility. It provides an internal investigation method.

  Means for solving the problems of the present invention are a method for investigating the inside of a reactor pressure vessel in a nuclear power plant, the step of penetrating a structure up to the inside of the reactor pressure vessel, and the structure subjected to the penetration processing The method includes a step of securing an access route in an object and a step of inserting a device using the access route.

  Even if it is difficult to carry out a normal investigation procedure, it becomes possible to efficiently conduct investigation and maintenance work inside the RPV.

It is a flowchart of the work step applied to the investigation in RPV of the boiling water reactor (BWR: Boiling Water Reactor) in Example 1 of this invention. It is explanatory drawing which shows the cross-sectional schematic which applied the access path ensuring device inside RPV of BWR in Example 1 of this invention. It is explanatory drawing which shows the access route ensuring apparatus in Example 1 of this invention. It is explanatory drawing which shows the detail of the access route ensuring apparatus in Example 1 of this invention. It is explanatory drawing which shows the operation | work of step S2 of FIG. It is explanatory drawing which shows the operation | work of step S2 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S3 of FIG. It is explanatory drawing which shows the operation | work of step S4 of FIG. It is explanatory drawing which shows the operation | work of step S5 of FIG. It is explanatory drawing which shows the operation | work of step S6 of FIG. It is explanatory drawing which shows the operation | work of step S7 of FIG. It is explanatory drawing which shows the operation | work of step S8 of FIG. It is explanatory drawing which shows the operation | work of step S9 of FIG. It is explanatory drawing which shows the operation | work of step S10 of FIG. It is explanatory drawing which shows the cross-sectional schematic in Example 2 of this invention. It is explanatory drawing which shows the access route ensuring apparatus in Example 2 of this invention.

  The present invention will be described with reference to the drawings, taking as an example an investigation in a reactor pressure vessel (RPV) in a boiling water reactor (BWR).

  FIG. 1 is a flowchart of work steps applied to the RPV investigation in the present invention.

  FIG. 2 is a schematic cross-sectional view of a BWR reactor building and an RPV. In a regular periodic inspection, the shield plug 1, the reactor containment vessel lid 2, and the reactor pressure vessel lid 3 are sequentially removed, and further, the reactor well 4 located at the top of the reactor pressure vessel is filled with water, In general, the in-reactor equipment 5 (steam dryer 101, steam separator 102, etc.) is taken out sequentially, and the inside of the reactor pressure vessel, maintenance work, etc. are performed. However, in the unlikely event that an emergency situation occurs in which the overall function of the reactor building is lost, it may be considered that these structure removal devices (not shown) do not operate.

  In such a case, for example, in order to investigate the location A inside the reactor pressure vessel 100 shown in FIG. 2, the location E of the shield plug 1, the location D of the reactor containment vessel lid 2, the reactor It is necessary to provide a through-hole in the location C of the pressure vessel lid 3 and the location B (steam dryer and steam separator if necessary) at the steam dryer 101 and the steam / water separator 102. However, when the through hole is provided, a thin member is selected in advance, or the investigation location can be efficiently reached by using the already provided through hole. For example, when a through hole is provided vertically on the same axis, it is not efficient because it is necessary to provide a through hole in a thick member. Therefore, FIG. 2 shows an example of a route through which the through hole can be efficiently provided.

  3 and 4 show an access route securing device 21 for securing an access route that is used when the investigation device is taken in and out of the reactor pressure vessel 100. FIG. The access path securing device 21 includes a guide pipe 7 including a penetrating material 6 (for example, a water jet cutting nozzle and a laser cutting nozzle) included in the tip, and an incidental facility 8 for the penetrating material (for example, a water jet cutting device main body, A laser cutting device main body), a guide pipe operating mechanism 22 for operating the guide pipe 7, and a guide pipe feeding mechanism 9.

  As shown in FIG. 4, the guide pipe operating mechanism 22 for operating the guide pipe 7 has a plurality of wire adjusting mechanisms 23 so that the tensions of the plurality of wires 13 can be adjusted. Around the guide pipe 7, a plurality of wires 13 are provided through hooks 24. The lengths of the wires 13 are different from each other so that the movement of the guide pipe 7 can be controlled at a predetermined location. Further, an outer cylinder cover 25 is provided around the guide pipe 7 so that the wire 13 is not caught outside during insertion. The outer cylinder cover 25 may be unnecessary.

  In this embodiment, the investigation work in the RPV is performed by the method shown in the flowchart shown in FIG. The following describes each work step.

  In step S1, the guide pipe 7 including the penetrating material 6 at the tip, the incidental equipment 8 of the penetrating material, and the guide pipe feeding mechanism 9 are carried into the reactor building and installed. FIG. 2 is a diagram in which these facilities are installed on the floor 10.

  In the following description, the operation at the location B in FIG. 2 will be described as a representative from FIG. A case where water jet cutting is used as the penetration processing equipment 6 will be described. In addition, although description is abbreviate | omitted, the location C, the location D, and the location E are the same work steps fundamentally.

  Next, in step S2, the entire guide pipe 7 is fed into the RPV by the guide pipe feeding mechanism 9.

  As shown in FIG. 5, in addition to the penetration processing equipment 6, a camera 12 fixed by a fixing jig 11 is included at the tip of the guide pipe 7. Check the situation beyond the tip. A plurality of wires 13 whose tension can be adjusted on the floor 10 are attached to the outside of the guide pipe 7 from the tip and middle positions of the guide pipe to a guide pipe operating mechanism 22 provided on the floor 10. 7, a plurality of variable nodes 14 are provided over the entire length. The function of the camera 12 and the function of the node by changing the tension of the wire 13 make it possible to move the guide pipe head to an arbitrary location and to install the tip of the guide pipe 7 on the structure 15. (FIG. 6).

  7 to 14, the structure penetrating work by the penetrating material 6 in the next step S <b> 3 will be described.

  First, the preparation work before starting the penetration process will be described. Water pressurized by a pump is injected into the high-pressure hose 26. In addition to the high-pressure hose 26, an abrasive injection hose 27 for injecting an abrasive may be provided. This is because an abrasive is sometimes mixed with high-pressure water in order to increase the cutting efficiency of water jet cutting, and the mixture is injected. Further, a recovery nozzle 16 connected to a recovery device (not shown) for recovering the mixed material and fixed by the fixing jig 11 is attached to the tip of the guide pipe 7 so that the mixed material can be recovered appropriately. Do. In addition, in order to prevent the abrasive from scattering to the outside of the guide pipe 7, a mixed water scattering prevention cover 17 whose size can be arbitrarily changed by the air supply tube is attached to the outside of the tip of the guide pipe 7. The mixed water scattering prevention cover 17 is inflated by supplying air, and the water jet cutting device and the abrasive recovery device are activated (FIG. 7).

  The water jet cutting device is then activated for processing. A hole is made in the structure 15 by the cutting effect of the mixed water of high pressure water and abrasive (FIG. 8). Here, it is possible to proceed with the processing as it is, to open the through hole in the structure 15 and then to expand the through hole to the outside. However, if the through hole is opened, it is mixed in the space 18 on the side opposite to the cutting side. If the amount of outflow is to be suppressed because the water will flow out, the drilling process will be interrupted in consideration of the thickness of the structure 15, and the remaining thickness 19 of the penetrating part will serve as a lid, with the hole outside. An expanding method is also conceivable. Hereinafter, this method will be described.

  With the functions of the camera 12, the wire 13, and the node 14, the holes are sequentially drilled concentrically with reference to the holes drilled in FIG. 8, and the holes are expanded as a whole (FIG. 9). By adjusting the tension of each wire 7 provided on the guide pipe 7 by the wire adjusting mechanism 23, the guide pipe 7 is moved to a target place using each node 14 of the guide pipe 7, and the camera 12 uses the guide pipe 7. While observing the position of, check the size of the hole, and then expand the hole. Furthermore, the same procedure is continued and the hole is expanded to a size that allows the entire guide pipe 7 to pass through the through hole (FIG. 10). At this time, since the mixed water scattering prevention cover 17 is inflated, it is possible to prevent the mixed water from scattering to the outside of the guide pipe 7 even when the outermost peripheral hole is drilled.

  After expanding the hole to a size that allows the entire guide pipe 7 to pass through the through-hole, the function of the camera 12, the wire 13, and the node 14 is used to return the hole to the position where it was first drilled (FIG. 11), thereby serving as a lid. In order to perform the penetrating process of the structure 15, the penetrating apparatus 6 is lowered and the penetrating process is performed. After that, penetration processing is performed in the same manner as the procedure shown in FIG. 9 and FIG. 10 (FIGS. 12 and 13). The equipment 6 is returned to the initial position, the water jet cutting device and the abrasive recovery device are stopped, the air supply is stopped, and the mixed water scattering prevention cover 17 is contracted (FIG. 14).

  Next, in step S4, the entire guide pipe 7 is further fed into the RPV by the guide pipe feeding mechanism 9 (FIG. 15).

  Next, in step S5, while repeating steps S3 and S4, the tip of the guide pipe 7 is fed to the investigation position in the RPV (location A in this embodiment) (FIG. 16). At this time, the tension of each wire 7 provided on the guide pipe 7 is adjusted by the wire adjusting mechanism 23 so that the guide pipe 7 is moved to the target location by using each node 14 of the guide pipe 7. Work can be carried out.

  After completion of the drilling operation up to the target position to be the investigation location, next, in step S6, the penetration processing equipment 6, the camera 12, the recovery nozzle 16, and the fixing jig 11 are removed, and the floor 10 is recovered ( FIG. 17). The guide pipe remains installed at the current position. Although not shown, the fixing jig 11 is provided with a locking mechanism, and the fixing jig 11 is attached to the tip of the guide pipe 7 by the locking mechanism. By releasing the lock mechanism, the penetration processing equipment 6, the camera 12, and the recovery nozzle 16 provided in the fixing jig 11 can be recovered. By leaving the guide pipe 7 without collecting it, it is possible to efficiently insert various devices up to the investigation location in the subsequent work.

  Next, in step S7, the guide pipe feeding mechanism 9 and the auxiliary equipment 8 installed on the floor 10 are removed from the guide pipe 7 (FIG. 18). The path for inserting the finally formed investigation device is as shown in FIG.

  Next, in step S8, the investigation equipment 20 is inserted into the guide pipe 7 from the opening of the guide pipe 7 on the floor 10, and is taken out into the opening inside the RPV by the guide function of the guide pipe 7, An investigation is performed (FIG. 19).

Next, in step S9, the survey equipment 20 is collected by the guide function of the guide pipe 7 after the survey is completed (FIG. 20). By repeating steps S8 and S9, a plurality of investigation equipment can be taken out to the opening on the RPV side, and various investigations in the RPV can be conducted.
In this way, by using the guide pipe 7 during the investigation, the apparatus can be taken in and out efficiently, and the overall work efficiency is also greatly improved.

  Next, in step S10, collection is performed up to the floor 10 of the guide pipe 7 by the function of the node 14 (FIG. 21).

  In the present embodiment, even if it is difficult to carry out the normal investigation and maintenance work procedure due to the occurrence of an accident at the reactor facility by penetrating the guide pipe 7 to the inside of the RPV in advance. In addition, it becomes possible to efficiently conduct investigation and maintenance work inside the RPV.

  A second embodiment of the present invention will be described with reference to the drawings. Since the work steps are the same as those in the first embodiment, description thereof is omitted.

  In the second embodiment, as shown in FIG. 22, a sealed chamber 28 and a filter 29 are provided. Thereby, it becomes possible to work without leaking the radioactive substance in the RPV to the outside. As shown in FIG. 23, the guide pipe 7 may be moved by a hydraulic or air adjusting mechanism 30, a damper 31, and a plurality of hoses 32 that connect the adjusting mechanism 30 and the damper 31 instead of a wire. By adopting such a configuration, finer control of the guide pipe 7 is possible.

DESCRIPTION OF SYMBOLS 1 ... Shield plug 2 ... Reactor containment vessel lid 3 ... Reactor pressure vessel lid 4 ... Reactor well 5 ... In-reactor equipment 6 ... Penetration processing equipment 7 ... Guide pipe 8 ... incidental equipment 9 ... guide pipe feeding mechanism 10 ... floor 11 ... fixing jig 12 ... camera 13 ... wire 14 ... node 15 ... structure 16 ... Recovery nozzle 17 ... Mixed water scattering prevention cover 18 ... Space 19 ... Thickness 20 ... Investigation equipment 21 ... Access path securing device 22 ... Guide pipe operation mechanism 23 ... Wire adjusting mechanism 24 ... Hook 25 ... Outer cylinder cover 26 ... High pressure hose 27 ... Abrasive injection hose 28 ... Sealed chamber 29 ... Filter 30 ... Adjusting mechanism 31 ... -Damper 32 ... Hose 100 ... Reactor pressure vessel 10 ... steam dryer 102 ... steam separator

Claims (9)

In the investigation method inside the reactor pressure vessel in the nuclear power plant,
A step of penetrating the structure leading to the inside of the reactor pressure vessel;
Securing an access path in the through-processed structure;
A method for investigating the inside of a reactor pressure vessel, comprising the step of inserting equipment using the access path. In the investigation method inside the reactor pressure vessel according to claim 1,
The method for investigating the inside of the reactor pressure vessel is characterized in that the access path is secured by using an outer cylinder used in the penetration process. In the investigation method inside the reactor pressure vessel according to claim 1,
A method of investigating the inside of a reactor pressure vessel, characterized in that a guide pipe is provided on the investigation path at the same time as the penetration processing is performed. In the investigation method inside the reactor pressure vessel according to any one of claims 1 to 3,
The penetration processing includes drilling to a predetermined depth, expanding the size in the width direction of the hole drilled to the predetermined depth, and then providing a through hole in the remaining member of the structure in which the hole is formed. An investigation method inside the reactor pressure vessel. In the investigation method inside the reactor pressure vessel according to any one of claims 1 to 4,
The method of investigating the inside of a reactor pressure vessel is characterized in that the step of inserting equipment using the access path comprises inserting and removing a plurality of investigation equipment. In the investigation equipment inside the reactor pressure vessel in a nuclear power plant,
A guide pipe having a plurality of nodes;
An operating mechanism for operating the guide pipe;
A penetrating device provided at the tip of the guide pipe;
An investigation device inside a reactor pressure vessel, comprising a camera provided at a tip of the guide pipe. In the investigation device inside the reactor pressure vessel according to claim 6,
The investigation device inside a reactor pressure vessel, wherein the operation mechanism is a plurality of wires provided in the guide pipe and a wire adjustment mechanism for adjusting the wires. In the investigation device inside the reactor pressure vessel according to claim 6,
The operation device is a plurality of dampers provided in the guide pipe and an adjustment mechanism for adjusting the dampers. In the investigation apparatus inside the reactor pressure vessel according to any one of claims 6 to 8,
The penetration device is a water jet cutting device, and a scattering prevention cover is provided on the outer periphery of the tip end of the guide pipe.