JP2003262695A - Underwater remote surface inspection device in reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underwater remote surface inspection device in a reactor which is capable of accurately checking and inspecting reactor inside and core internal surface in a short time. <P>SOLUTION: The device comprises a device body 30 which is hung downward in a reactor filled with water, an inspection device 37 assembled in the device body and inspecting surface flaws on reactor inner surface as an inspection surface or reactor internals, and positioning mechanisms 31 and 32 for positioning the inspection device in the reactor. The inspection device comprises a sealing chamber 38 having an opening press-sealed on the inspection surface, a chemical liquid supply means 41 for supplying the sealing chamber with conductive chemical liquid, electrodes arranged in the sealing chamber and a power- supply unit. It also comprises an etching means 40 for etching the inspection surface, a chemical liquid exhaust means 41 for exhausting chemical liquid out of the sealing chamber, and a replica sampling means 42 for supplying the sealing chamber, where chemical liquid is exhausted with replica agent and sampling the surface state of the inspection surface. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor capable of highly accurately inspecting the surface of a reactor internal surface or the surface of a reactor internal structure for cracks, corrosion, etc. during the service period of a nuclear power plant. Underwater remote surface survey equipment.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a boiling water reactor. This boiling water reactor 1 is equipped with a reactor pressure vessel 2 which is a reactor vessel. Inside the reactor pressure vessel 2, a steam dryer 3, a steam separator 4, and fuel assemblies 5, 5 ... 5 are sequentially arranged from the top. Each fuel assembly 5 is a columnar member provided with a plurality of elongated fuel rods (not shown), and each fuel rod is formed by covering a plurality of uranium dioxide pellets with a fuel cladding tube. In the gap between the fuel assemblies 5, control rods 6, 6, ... 6 movable in the longitudinal direction thereof.
6 are inserted, and these control rods 6, 6 ... 6 are connected via rods 7a, 7a ...
Driven in the vertical direction by control rod drive mechanisms 7, 7 ... 7 provided in the lower portion of the reactor pressure vessel 2.

The control rod drive mechanism 7 is a cylindrical C extending from the lower portion of the reactor pressure vessel 2 through the reactor pressure vessel 2.
7b, and rods 7a, 7a ... 7a are CRD housings 7b, 7b ... 7b.
Has been inserted inside. A flange 7c thicker than the outer diameter of the CRD housing 7b is formed.

The inside of the reactor pressure vessel 2 is a fuel assembly 5,
5 ... 5 is filled with reactor water (light water) 8 to a position where it is fully submerged, and this reactor water 8 functions as a moderator and a coolant for the nuclear reactor 1. The heat generated by the nuclear fission reaction in the fuel assembly 5 is transferred to the reactor water 8, and the transferred heat causes the reactor water 8 to boil. The boiling reactor water 8 is separated into steam and water by the steam separator 4 and then the steam outlet 2a.
To the steam turbine (not shown). Further, the output control of the nuclear reactor 1 is performed by the plurality of fuel assemblies 5, 5, ...
Control rod drive mechanisms 7, 7, ... 7 for the core composed of 5
6 by inserting and pulling out the control rods 6, 6.

FIG. 7 shows a lower structure of a boiling water reactor, and this boiling water reactor comprises a reactor pressure vessel 2 which is a reactor vessel. The reactor pressure vessel 2 is supported on a support pedestal 16 via a support skirt 17.

A control rod drive mechanism (CRD) is provided in the lower portion (lower mirror) of the reactor pressure vessel 2 to insert and pull out a control rod (not shown) from a reactor core (not shown).
A large number of 7 are erected in a standing state. These control rod drive mechanisms 7 are cylindrical CR made of stainless steel.
The CRD housing 7b is provided with a D housing 7b from the lower part of the reactor pressure vessel 2 to the reactor pressure vessel 2
And is fixed by the lower mirror of the reactor pressure vessel 2.

A plurality of neutron flux detectors 21 are appropriately arranged in the gaps between the control rod drive mechanisms 7, and these neutron flux detectors 21 are long housings, which are neutron flux monitor guide tubes 22. And neutron monitor housing (in-core monitor housing: ICM housing) 23
Is equipped with. The upper part of the neutron monitor housing 23 is
It is inserted into a through hole of a reactor pressure vessel 2 having carbon steel as a base material and fixed by welding from the inside of the reactor pressure vessel 2.

In the following description, the CRD housing 7b and the neutron monitor housing 23 are collectively referred to as the reactor vessel penetrating housing 25.

FIG. 8 is a sectional view showing a state in which the CRD housing 7b, which is one of the reactor vessel penetrating housings 25, is fixedly supported on the bottom of the reactor pressure vessel 2. As shown in FIG. 8, a stainless steel build-up portion 9 is formed by welding on the inner surface of the reactor pressure vessel 2 and is mirror-finished.
A stub tube 10 is welded to the inclined portion of the through hole 2b of the reactor pressure vessel 2 by a welded portion 11 of an Inconel material which is a heat-resistant and corrosion-resistant alloy. Furnace pressure vessel 2
Forms a stand for fixing to the bottom of the. A groove portion is formed at the top of the stub tube 10, and this groove portion is also CRD via the welded portion 12 formed of Inconel material or the like.
It is fixed to the housing 7b and sealed. The welded portion 12 of the stub tube 10 separates the CRD housing 7b from the pressure boundary 13 located below the reactor pressure vessel 2 and isolates it from the reactor water environment.

[0010]

Inspection of the inner surface of the reactor pressure vessel 2 or the surface of the reactor internal structure as described above,
When conducting an inspection, the water depth is as deep as 20 meters, and
There is a problem that the workability is poor and the work takes a long time because it is a remote operation underwater in a narrow place.

That is, in order to find, for example, stress corrosion cracking (IGSCC) in the reactor and internal structures, it is necessary to accurately inspect and inspect the inner surface of the reactor pressure vessel 2 or the surface of the internal structure of the reactor. In addition, it is required to do it in a short time.

Under such circumstances, conventionally, it has been proposed to utilize the replica collecting means to measure the size and shape of the mounting portion of the control rod drive mechanism housing (Japanese Patent Laid-Open No. 7-
270581). By applying this technology, it is considered possible to meet the above demands.

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to accurately and quickly inspect and inspect the inner surface of the reactor and the surface of the inner structure of the reactor. The purpose is to provide a survey device.

[0014]

In order to solve the above-mentioned object, the invention according to claim 1 is an apparatus main body that is suspended in a water-tightened nuclear reactor, and is incorporated in this apparatus main body, and the surface to be inspected is An inspection device for inspecting a surface defect of a reactor internal surface or a reactor internal structure, and a positioning mechanism for positioning the inspection device in the reactor, the inspection device,
A seal chamber having an opening that is sealed by pressure contact with the surface to be inspected, a chemical solution supply means for supplying a conductive chemical solution to the seal chamber, an electrode arranged in the seal chamber, and an electric current to the electrode. An etching unit configured to etch the surface to be inspected, which is composed of a power supply device, a chemical liquid discharging unit for discharging the chemical liquid from inside the seal chamber, and a replica agent supplied to the seal chamber from which the chemical liquid has been discharged, the surface to be inspected And a replica collecting means for collecting the surface condition of the underwater remote surface inspecting apparatus in a nuclear reactor.

According to a second aspect of the present invention, in the underwater remote surface inspection apparatus for a nuclear reactor according to the first aspect, the chemical liquid supply means includes a chemical liquid tank for storing the chemical liquid, and the chemical liquid stored in the chemical liquid tank is compressed air. And a chemical solution supply hose for supplying the chemical solution to the seal chamber by means of the chemical solution discharge means, and the chemical solution discharge means introduces the chemical solution, which has been etched, from the seal chamber to the air using the compressed air source and collects the chemical solution. Also provided is an underwater remote surface inspection device in a nuclear reactor, which is equipped with a chemical solution recovery container.

According to a third aspect of the invention, in the underwater remote surface inspection apparatus for a nuclear reactor according to the first aspect, an etching means for supplying a conductive chemical solution to the seal chamber for etching and a replica agent are supplied. (EN) An underwater remote surface inspection apparatus in a nuclear reactor, characterized in that the replica collecting means for collecting the surface corrosion state by a different structure.

According to a fourth aspect of the invention, in the underwater remote surface inspection apparatus for a nuclear reactor according to the first aspect, a check valve is provided on each of the chemical solution supply hose of the chemical solution supply means and the chemical solution discharge hose of the chemical solution discharge means. An underwater remote surface inspection device in a nuclear reactor, which is characterized by being provided.

According to a fifth aspect of the present invention, in the underwater remote surface inspection apparatus for a nuclear reactor according to the first aspect, the power supply device of the etching means automatically automatically supplies the conductive chemical into the opening. An etching start confirmation circuit section that confirms the start of etching of the reactor internal structure surface by supplying a small current, and for etching that causes the reactor internal structure surface to be etched by supplying a predetermined current for a certain period of time. An underwater remote surface inspection apparatus in a nuclear reactor, comprising: a circuit section.

According to a sixth aspect of the present invention, in the underwater remote surface inspection apparatus for a nuclear reactor according to the first aspect, the replica collecting means is a transparent hose provided in a pipe portion through which the replica agent flows, and the transparent hose. And an underwater camera capable of visually confirming that the replica agent has been supplied into the seal chamber, and an underwater remote surface inspection apparatus in a nuclear reactor.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. In addition, in this embodiment, the reactor pressure vessel of the boiling water reactor and the reactor internal structure are inspected. Therefore, in the following description, FIG.
Also refer to FIG. Further, in the description in FIGS. 1 to 5, the same components as those in FIGS. 6 to 8 are denoted by the same reference numerals as those shown in these drawings.

FIG. 1 is a block diagram showing the entire underwater remote surface inspection apparatus in a reactor according to the present embodiment. A stainless steel buildup portion 9 provided on the inner surface of the reactor wall of a reactor pressure vessel 2,
An inconel welded portion 11 (an example in which a welded plate 9a made of the same material is provided on the stainless build-up portion 9) with the stub tube 10 around the CRD housing 7b is illustrated as an inspection target.

FIG. 2 is an explanatory view showing details of the lower side portion of FIG. 1, and FIG. 3 is an explanatory view showing details of the upper side portion of FIG.

In this embodiment, the reactor pressure vessel 2
A main body pole 30 is provided as a main body of the apparatus suspended inside, and a flange 31 as a positioning mechanism is provided at a lower end portion of the main body pole 30. Flange 3
1 is seated on the upper surface of the CRD housing 7b. The CRD housing 7b is provided below the center of the flange 31.
A vertically elongated guide rod 32 is attached to the lower part of the inside from the upper end opening. This guide rod 32
Is stably supported by the peripheral portion thereof being locked to the upper end ring 33 of the CRD housing 7b.

On the other hand, at the upper end of the main body pole 30,
As shown in FIG. 3, a cross-blade-shaped guide member 34 is attached, and the guide member 34 is inserted into the control rod insertion hole 15 a portion of the core support plate 15. The main body pole 30 has a hanging portion 35 provided further on the upper end side of the guide member 34, and is hung from above by a crane wire or the like (not shown) via the hanging portion 35. . As a result, the main body pole 30 is
The core support plate 15 is guided by the guide member 34 at the upper end to move up and down, and is positioned in the CRD housing 7b by the flange 31 or the like provided as a positioning mechanism at the lower end.

An azimuth guide 36 including a pair of vertical plates facing each other in the horizontal direction is attached to the side of the blade portion of the guide member 34 provided at the upper end of the main body pole 30. The guide 36 engages with the positioning pin 16 projecting from the upper surface of the core support plate 15 so that the orientation of the main body pole 30 can be determined. Thereby, a positioning mechanism is also configured on the upper end side of the main body pole 30.

Next, the structure of the inspection device 37 provided on the main body pole 30 as an underwater remote surface inspection device will be described.

The inspection device 37 is roughly classified into a seal chamber 38 having an opening portion which is sealed by pressure contact with the surface of a reactor or an internal structure of the reactor to form a local space, and a conductive chemical liquid in the seal chamber 38. The chemical liquid supply means 39 for supplying, the etching means 40 for etching the surface of the Inconel welded portion 11 which is an internal structure of the reactor, the chemical liquid discharge means 41 for discharging the chemical liquid from the seal chamber 38 after the etching, and the chemical liquid were discharged. A replica collecting means 42 for supplying a replica agent to the seal chamber 38 and collecting the surface state of the Inconel welded portion 11 is provided. The inspection device 37 including these devices is covered with a cover 43.

First, as shown in the enlarged view of FIG. 2, the seal chamber 38 is provided with a retainer fitting attached to the lower end of an arm 45 extending downward from a fixed plate 44 attached near the lower end of the main body pole 30. Formed by 46. The fixed plate 44 is fixed to a support column 47 fixed inside the main body pole 30 via a fastener 48. The holding metal fitting 46 includes an arc plate-shaped main member 46 a that covers the periphery of the Inconel welded portion 11, and the main member 46.
An auxiliary member 46 attached to the upper and lower positions of a and covering a fixed region of the outer peripheral surface of the Inconel welded portion 11 along the vertical direction.
b and 46c. And each of these members 4
A seal chamber 38 having an opening facing the surface of the Inconel welded portion 11 is formed in the inspected portion of the Inconel welded portion 11 by 6a, 46b, and 46c.

A sealing material 49 is provided at the tip of the auxiliary members 46b and 46c, which are the peripheral frame portion of the seal chamber 38, and the sealing material 49 comes into pressure contact with the surface of the Inconel welded portion 11 which is the portion to be inspected. As a result, the opening of the seal chamber 38 is adapted to perform pressure contact sealing with the surface of the inspected part. As the sealing material 49, a two-layer rubber material in which a highly flexible rubber material is disposed on the tip side facing the opening of the seal chamber 38 is applied, and the periphery thereof is a non-metal, for example, nylon resin fixing plate. The enclosed structure is used. As a result, the seal chamber 3
The respective members 46b and 46c forming 8 can be pressed against the surface of the Inconel welded portion 11 while maintaining electrical insulation, and the inside of the seal chamber 38 can be sealed.

Further, each adjusting mechanism 50, 51 for adjusting the vertical position of the seal chamber 38 and adjusting the pressure contact force for the pressure contact seal against the surface to be inspected is fixed plate 44, arm 4.
5 and a drive unit and the like provided in these units. As shown in FIG. 2, the vertical position adjusting mechanism 50 is configured by attaching an air cylinder 52 to the fixed plate 44 and connecting a downward drive rod 53 of the air cylinder 52 to the upper end of the arm 45 described above by a pin 54. Has been done. That is, by making the drive rod 53 of the air cylinder 52 project and retract downward, the arm 45 connected to the drive rod 53 is moved up and down.
It is possible to adjust the vertical position of the holding metal fitting 46 provided at the lower end of the seal chamber 38 and the seal chamber 38.

Further, the press contact force adjusting mechanism 51 allows the lower end side of the arm 45 to rotate in the direction of contacting and separating from the stub tube 10 with the pin 54 as a fulcrum, and the arm 45 is moved by the wedge mechanism 55. It is configured to be pushed toward the stub tube 10 side. That is, the wedge mechanism 55
Includes a fixed wedge 56 provided on a surface of the arm 45 on the side opposite to the stub tube 10 and having a wedge slope facing upward, and a movable wedge 57 having a wedge slope facing the wedge slope of the fixed wedge 56.
The movable wedge 57 is moved up and down by the air cylinder 58 to press the fixed wedge 56 and move the arm 45 to the stub tube 10 side.

The air cylinder 58 is a vertically long support plate 5 connected to the tip of the fixed plate 44 at the position of the cover 43.
9 is mounted on the air cylinder 58 via a bracket 60, and the moving wedge 5 is attached to the downward drive rod 61 of the air cylinder 58.
A wedge rod 62 protruding from the upper surface of 7 is connected via a horizontal pin 64. Then, the moving wedge 57 is vertically guided along the vertical direction on the surface opposite to the fixed wedge 56 by the wedge guide 63 provided at the lower end position of the cover 43,
When moving downward, the arm 45 is pushed toward the stub tube 10 side via the fixed wedge 56. As a result, the presser fitting 4
6 and eventually the seal chamber 38 moves to the stub tube 10 side, and the sealability of the seal chamber 38 is enhanced. The wedge guide 63 may urge the pin 54 of the drive rod 53 of the air cylinder 52 to the seal chamber 38 side by, for example, a tension spring 63a. Further, in order to reduce the sealing performance, the drive rod 61 of the air cylinder 58 may be raised and the operation reverse to the above may be performed.

Next, with reference to FIGS. 1 and 4, the chemical liquid supply means 39, the etching means 40 and the chemical liquid discharge means 41.
Will be described. FIG. 1 shows these means 39, 40,
FIG. 4 shows a detailed system configuration, such as the arrangement of the main members constituting 41.

The chemical supply means 39 is a seal chamber 38.
4, a chemical solution for etching is supplied by compressed air. As shown in FIG. 4, a chemical solution tank 66 containing a constant quantity of conductive chemical solution (for example, 10% oxalic acid) 65 is provided. The chemical solution 65 is supplied to the seal chamber 38 through the chemical solution supply hose 67. The chemical solution supply hose 67 is provided with a check valve 68 to prevent the reverse flow from the seal chamber 38 side to the chemical solution tank 66 side. The chemical liquid 65 is supplied from the chemical liquid tank 66 to the seal chamber 38 by compressed air. That is, an air supply source such as a compressor (not shown), a regulator 69 for adjusting the compressed air supplied from the air supply source, a pressure adjusting mechanism 71 having a pressure gauge 70, etc. are provided, and the flow rate connected to this is provided. Compressed air is supplied to the chemical liquid tank 66 via an air supply hose 73 having a control valve 72. By the supplied compressed air, the chemical liquid 6 in the chemical liquid tank 66 is
5 is pressed and supplied to the seal chamber 38 via the air supply hose 73. The chemical liquid tank 66 is arranged in the water 74 stretched over the reactor pressure vessel 2, and the air supply source is arranged in the air above the reactor pressure vessel 2.

FIG. 1 shows the mounting structure of the chemical liquid tank 66, the chemical liquid supply hose 67, the air supply hose 73 and the like to the main body pole 30. As shown in FIG. 1, the chemical liquid tank 66 is supported above the seal chamber 38 of the main body pole 30 via a support tool 101. The chemical solution supply hose 67 led from the chemical solution tank 66 hangs down via the arm 45 and is connected to the holding metal fitting 46. As shown in an enlarged view in FIG. 4, a chemical liquid supply hole 75 communicating with the chemical liquid supply hose 67 is provided in the holding metal fitting 46, and the chemical liquid 65 is introduced into the seal chamber 38 through the chemical liquid supply hole 75. . In this case, the chemical liquid 65 flows in the seal chamber 38 from the lower side to the upper side.

The etching means 40 is the seal chamber 3
An electrode 77 arranged in a non-contact state with the surface to be inspected within 8,
A power supply device 78 for supplying a current to the electrode 77 from the air side
It is composed of and. The electrode 77 is made of a corrosion-resistant metal, such as a platinum plate, and is provided so as to face the surface of the Inconel weld 11 that is the surface to be inspected.
The power supply device 78 is, for example, a rectifier 7 connected to a commercial power supply.
9, the DC current from the rectifying board 79 is connected to the electrode 77 via the holding metal fitting 46, and one etching cable 80 and the outside of the seal chamber 38, that is, the reactor wall of the reactor pressure vessel 2 or Electricity is supplied by the other etching table 81 connected to the stub tube 10 or the like as the furnace internal structure.

In the etching means 40, the chemical solution supply means 39 supplies the chemical solution into the seal chamber 38 and energizes the electrode 77 to corrode the inconel welded portion 11 which is the surface to be inspected. . In this case, in this embodiment, the power supply device 78
The control device provided in the above makes it possible to perform the etching action efficiently and surely by associating the supply of the chemical liquid with the energization.

That is, the control device has a circuit portion for confirming the start of etching. In the etching start confirming circuit portion, a switch portion for turning on the power source of the power supply device 78 in advance for supplying the chemical liquid 65 and a small voltage of several volts applied to the electrode 77 when energization is started by the switch portion. And a voltage setting unit for supplying a current. Then, at the same time that the chemical solution 65 is supplied to the seal chamber 38, a small current is automatically supplied, whereby the chemical solution 65 is supplied to the seal chamber 38, and it is confirmed that the etching of the Inconel weld 11 is started. It is supposed to be done.

Further, the control device is provided with an etching circuit section for controlling the etching action after confirmation of the start of etching. This etching circuit unit has a current switching unit that switches to a current supply of a predetermined voltage as an etching current after the start of etching is confirmed, and an etching time corresponding to the material of the surface to be inspected after the current switching. And a timer unit for setting. As a result, the necessary etching is automatically and surely performed by the current of the predetermined voltage.

The chemical liquid discharging means 41 is a seal chamber 38.
The chemical liquid after the etching is discharged by the compressed air force. That is, as shown in FIG. 4, the chemical liquid discharge means 41 has an air supply hose 82 for supplying compressed air to the seal chamber 38 from the pressure adjusting mechanism 71 applied in the chemical liquid supply means 39.
A check valve 83 is provided in the. Further, a chemical solution discharge hose 84 for discharging the chemical solution after the etching is completed is provided on the air side from the seal chamber 38, and the chemical solution discharge hose 84 is connected to the chemical solution recovery tank 85. A check valve 86 is provided on the chemical liquid discharge hose 84. And
After the above-described etching is completed, the compressed air supplied from the air supply hose 82 is supplied to the upper portion of the seal chamber 38 to be pressurized, whereby the chemical liquid in the seal chamber 38 is discharged through the chemical liquid discharge hose 84 to a waste liquid recovery tank. It is accommodated in 85.

In the chemical liquid discharging means 41, after the chemical liquid tank 66 is empty, cleaning water is further fed into the chemical liquid tank 66 to clean the inside of the chemical liquid tank 66, and then the drainage tank in the air. It is also possible to provide a system for discharging the used cleaning liquid.

Next, the replica collecting means 42 will be described with reference to FIGS. 1 and 5. FIG. 1 shows the arrangement of main members constituting the replica collecting means 42, and FIG. 4 shows a detailed system configuration.

The replica collecting means 42 collects the surface-corroded member of the Inconel welded portion 11 etched by the above-mentioned etching means 40 with a replica agent. As shown in FIG. 5, the replica collecting means 42
Is a replica agent container 87 for containing the replica agent, an air cylinder device 88 for extruding the replica agent from the replica agent container 87, a mixer 89 for mixing the extruded replica agent, and a seal chamber from the mixer 89. A replica agent supply hose 90 for supplying a replica agent to the unit 38, a transparent filling confirmation hose 91 for confirming that the replica agent is filled in the seal chamber 38, and an underwater camera 92 are provided.

The replica agent container 87 has a structure in which two rows of vertically cylindrical container parts for separately storing two liquids are provided, and the air cylinder device 88 has the same air cylinder 93.
In addition, two downward driving rods 94 and 95 are provided in parallel. Driving air is supplied to the air cylinder 93 from the air side through the air supply hoses 96 and 97, whereby the drive rods 94 and 95 descend and the replica agent containing body 87 collects two replica agents. The mixer 89 is adapted to be extruded.

The mixer 89 is composed of one spiral tube or the like, and is mixed while the two-liquid replica agent passes through the inside thereof. Then, the mixed replica agent is supplied to the seal chamber 38 by the replica agent supply hose 90. The replica agent supply hose 90 is configured as a transparent hose so that the state of the replica agent can be confirmed from the outside.

For example, two replica agent passages 9 having different heights are provided in the pressing metal fitting 46 constituting the seal chamber 38.
8, 99 are formed, and the replica agent supply hose 90 is formed.
Are connected to a replica agent passage 98 on the low side which communicates with the lower portion of the seal chamber 38. As a result, the replica agent is gradually accommodated from the lower side in the seal chamber 38. A filling confirmation hose 91 is connected to the replica agent passage 99 communicating with the upper portion of the seal chamber 38.

The filling confirmation hose 91 is constructed as a transparent hose extending from the seal chamber 38 to the air, for example. When the replica agent is supplied after the replica agent is filled in the seal chamber 38, the surplus portion flows into the filling confirmation hose 91.

The underwater camera 92 is arranged at a position where the transparent filling confirmation hose 91 can be observed, and the observation result is displayed via a cable 100 on a monitor or the like, not shown, such as a control room. You can check the filling.

As shown in FIG. 1, the replica agent container 87, the air cylinder device 88, and the like described above are supported at a position below the chemical liquid tank 66 of the main body pole 30 via the same support tool 102, for example. There is.

Next, the operation will be described. As shown in FIGS. 1 to 3, in the underwater remote surface inspection apparatus for a nuclear reactor according to the present embodiment, all the constituent members are arranged on the main body pole 30 as the main body of the apparatus. The pole 30 is hung from the upper part of the reactor pressure vessel 2, and the flange 31 and the guide rod 32 as a positioning mechanism provided at the lower end of the main body pole 30 are attached to the CRD.
The guide member 34 on the upper side of the housing 7b is positioned and the control rod guide tube 15 of the core support plate is provided.
It can be positioned and fixed to a. In this case,
As shown in (B), the center of the stub tube 10 and the center of the main body portion pole 30 coincide with each other.

After the main body pole 30 is positioned and fixed, the seal chamber 38 is pressure-contacted and sealed to the stub tube 10 side by operating the wedge mechanism 55 and the like, and the seal chamber is formed on the surface of the inconel welded portion 11 to be inspected. Three
8 is a pressure contact sealing means.

In this state, first, as shown in FIG.
A conductive chemical solution is supplied from the chemical solution tank 66 of the chemical solution supply means 39 via the chemical solution supply hose 67 to the seal chamber 38, and at the same time, an electric current is supplied to the electrode 77 made of a platinum plate or the like of the etching means 40 to provide the internal structure of the furnace. The surface of the Inconel welded portion 11 is corroded.

In this case, as described above, the power supply 78
The etching start confirmation circuit section, voltage setting section, etc.
Necessary etching can be done automatically and surely.

After the etching is completed, the etching solution is discharged, and then the replica is sampled either continuously or by exchanging it with another seal chamber 38 for the replica sampling means 42. That is, the replica agent is mixed from the replica agent container 87 by the air cylinder device 88 and supplied to the seal chamber 38, and the underwater camera 92 confirms the filling, and the surface state of the Inconel welded portion 11 is sampled by the replica agent. Then, after a certain period of time, the main body part pole 30 is pulled up to the air, the replica agent is taken out, moved to a hot lab, and the structure part of the material is observed with a microscope to confirm the soundness.

According to the above-described embodiment, the main body pole 30 as the main body of the apparatus suspended in the reactor pressure vessel 2 is provided.
In addition, the inspection device 3 for investigating the surface defect of the Inconel welded portion 11 of the CRD housing 7b as the reactor internal structure
7, a local space is formed by the opening of the seal chamber 38 of the inspection device 37, and a conductive chemical solution is supplied into the seal chamber 38, and at the same time, a current is supplied to the electrode 77 in the seal chamber 38 to perform Inconel welding. By investigating the surface corrosion state by etching the surface of the portion 11 and supplying the replica agent into the seal chamber 38 in this state, the surface defect of the Inconel welded portion 11 as the reactor internal structure is investigated. Maintenance and inspection work such as can be performed accurately and in a short time.

Further, a predetermined amount of the chemical liquid is previously supplied to the chemical liquid tank 66 installed on the main body pole 30, and compressed air is supplied from the air supply hose 73 extending to the air to the inner surface of the seal chamber 38. When the chemical solution arrives, the voltage is adjusted and a constant current is applied for several minutes to etch the surface to be inspected in the seal chamber 38, and when the etching is completed, compressed air is supplied into the chemical solution tank 66 to empty the chemical solution container. In this state, cleaning water is sent as necessary to guide the chemical solution discharge hose 84 to the air above, and the chemical solution recovery tank 85 can be recovered, so that maintenance and inspection work such as defect inspection can be performed safely and accurately. It can be carried out.

The sealing material 49 used for the pressure contact sealing of the seal chamber 38 is a cylindrical two-layer structure having a soft rubber material at the tip and a hard rubber material having a high strength at the main body. This two-layer structure sealing material is fixed by surrounding it with a fixing plate made of a non-ferrous material, for example, a nylon material, and an electrode 77 is attached inside the sealing chamber 38, so that maintenance such as investigation of surface defects is performed. Inspection work can be performed safely and in a short time under a reliable seal.

Further, after the replica agent is supplied into the seal chamber 38 and the surface corrosion state of the surface to be inspected is sampled, the entire apparatus is pulled up to take out the replica agent from the seal chamber 38, and the replica agent is moved to a hot laboratory to be examined by a microscope. By observing the microstructure of the material, soundness can be surely confirmed.

It should be noted that the conductive chemical liquid is used as the seal chamber 38.
Electrode 7 formed on the inner surface of the seal at the same time as being supplied
A device for supplying an electric current to 7 to etch the surface to be inspected and a device for supplying a replica agent into the seal chamber 38 to sample the surface corrosion state are provided as separate devices, respectively. Maintenance and inspection work such as investigation of surface defects in the furnace structure can be performed safely and accurately.

Further, the conductive chemical liquid is used in the seal chamber 38.
When it is supplied to the inside, check valves are installed in the piping and drainage piping respectively so that the chemical solution does not remain in the piping, so maintenance and inspection work such as investigation of surface defects inside the reactor is safe. And it can be done reliably.

Further, the conductive chemical liquid is used in the seal chamber 38.
Since the seal portion supplied to the inside is a passage through which the chemical liquid flows from the lower side to the upper side, maintenance and inspection work such as investigation of surface defects in the reactor internal structure can be performed accurately and reliably.

Further, the conductive chemical liquid is used in the seal chamber 38.
As a method of confirming that the liquid has been supplied to the inside, by turning on the power supply of the power supply device in advance and setting the voltage to several volts, the chemical solution is automatically supplied to the seal chamber 38 at the same time. It can be confirmed that the surface etching of the reactor internals starts when an electric current is supplied, and the surface of the reactor internals can be reliably etched by applying a predetermined current for a certain period of time. Maintenance and inspection work such as defect inspection can be performed quickly and accurately.

Further, the replica agent is added to the seal chamber 38.
A transparent hose is installed in the pipe part that pulls up the entire apparatus to extract the replica agent from the seal chamber 38 after the surface corrosion state is collected, and the replica agent is supplied to the seal chamber 38. Since it is possible to visually confirm through the underwater camera 92, it is possible to accurately and surely perform maintenance and inspection work such as investigation of surface defects in the reactor internal structure.

In the above embodiment, the inspection target is the Inconel welded portion of the stub tube 10 in the CRD housing 7b of the reactor pressure vessel 2, but the present invention is not limited to this, and the reactor pressure vessel 2 The inner surface of the furnace wall or the surface of the inner structure of the furnace other than the above can be the inspection object.

[0065]

As described above, according to the present invention, it is possible to accurately inspect and inspect the surface portion of the inside of the reactor and the surface portion of the internal structure of the reactor.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an underwater remote surface inspection device for an internal structure of a reactor showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing details of a lower portion of FIG.

FIG. 3A is an explanatory diagram showing details of an upper portion of FIG.
(B) is an explanatory view showing the positional relationship between the air cylinder and the chemical liquid tank.

FIG. 4 is a circuit diagram of underwater etching.

FIG. 5 is a circuit diagram of an underwater remote replica.

FIG. 6 is a schematic configuration diagram of a boiling water reactor.

FIG. 7 is a schematic configuration diagram showing a lower structure of a boiling water reactor.

FIG. 8 is a vertical cross-sectional view showing a welded portion of the through-housing of the reactor vessel fixedly mounted on the bottom of the reactor pressure vessel.

[Explanation of symbols]

1 boiling water reactor 2 Reactor pressure vessel 7b CRD housing 8 core 9 Stainless steel build-up part 10 stub tubes 11 Inconel weld 12 Weld 30 body pole 31 flange 32 Guide rod 37 Inspection device 38 Seal chamber 39 chemical supply means 40 Etching means 41 Medication discharge means 42 means for collecting replicas 44 Fixed plate 45 arms 46 Presser bracket 49 Seal material 55 Wedge mechanism 66 Chemical tank 67 Chemical supply hose 73 Air supply hose 77 electrodes 82 Air supply hose 83 Check valve 84 Chemical solution discharge hose 86 Check valve 87 Replica agent container 88 Air cylinder device 89 mixer 90 Replica agent supply hose 91 Filling confirmation hose 92 underwater camera 96 supply air hose 98,99 Replica agent passage

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nei Kanazawa             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office (72) Inventor Motoshi Tsubota             2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa               Toshiba Keihin Office F term (reference) 2G075 AA03 CA07 DA15 FA13 FC03                       FC12 FC13 FC14 GA01 GA15

Claims (6)

[Claims] 1. An apparatus main body that is hung in a water-tight reactor, and an inspection apparatus that is incorporated in the apparatus main body and inspects a surface defect of a reactor inner surface which is a surface to be inspected or a reactor internal structure. A positioning mechanism for positioning the inspection device in the nuclear reactor, wherein the inspection device has a seal chamber having an opening that is pressure-contacted and sealed to the surface to be inspected;
A chemical solution supply means for supplying a conductive chemical solution to the seal chamber, an etching means for etching the surface to be inspected, which comprises an electrode arranged in the seal chamber and a power supply device for supplying a current to the electrode, and the seal. A chemical liquid discharging means for discharging the chemical liquid from the chamber, and a replica collecting means for supplying a replica agent to the seal chamber from which the chemical liquid has been discharged and collecting the surface state of the surface to be inspected are provided. Underwater remote surface inspection equipment inside the reactor. 2. The underwater remote surface inspection apparatus for a nuclear reactor according to claim 1, wherein the chemical solution supply means supplies a chemical solution tank containing the chemical solution and the chemical solution contained in the chemical solution tank to the seal chamber by compressed air. A chemical liquid discharge means having a compressed air source and a chemical liquid supply hose is provided with a chemical liquid discharge hose and a chemical liquid recovery container for guiding the etched chemical liquid from the seal chamber to the air by using the compressed air source and collecting the chemical liquid. Underwater remote surface survey equipment inside a nuclear reactor. 3. The underwater remote surface inspection apparatus for a nuclear reactor according to claim 1, wherein an etching means for supplying a conductive chemical solution to the seal chamber for etching, and a replica agent for collecting the surface corrosion state. An underwater remote surface inspection apparatus in a nuclear reactor, characterized in that the replica collecting means is configured to be different from each other. 4. The underwater remote surface inspection apparatus for a nuclear reactor according to claim 1, further comprising a chemical solution supply hose of the chemical solution supply means,
An underwater remote surface inspection device in a nuclear reactor, characterized in that a check valve is provided on each of the chemical solution discharge hoses of the chemical solution discharge means. 5. The underwater remote surface inspection apparatus for a nuclear reactor according to claim 1, wherein the power supply device of the etching means automatically supplies a small current at the same time when the conductive chemical is supplied into the opening. An etching start confirmation circuit unit for confirming the start of etching of the surface of the reactor internal structure, and an etching circuit unit for subsequently etching the surface of the reactor internal structure by supplying a predetermined current for a certain period of time were provided. An underwater remote surface inspection device in a reactor. 6. The underwater remote surface inspection apparatus for a nuclear reactor according to claim 1, wherein the replica collecting means is provided with a transparent hose provided in a pipe section through which the replica agent flows, and at a position where the transparent hose can be observed. An underwater remote surface inspection apparatus in a nuclear reactor, comprising: an underwater camera that is provided and is capable of visually confirming that the replica agent has been supplied into the seal chamber.