JPH09329687A - In-reactor inspection device - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To access various inspection jigs and tools to the annulus portion while avoiding a structure such as a low pressure water injection system coupling attached to the upper part of the shroud and a shroud overhang. SOLUTION: The guide mechanisms 22 and 23, which are positioned on the internal structure such as the jet pump 8 and the upper structure of the shroud 3 and allow the inspection head 27 having various inspection jigs and tools to access the annulus portion, and the annulus. A swivel mechanism 28 for swiveling the inspection head in the unit and a moving mechanism 24 for moving the inspection head in the annulus unit were provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention attaches a structure such as a low pressure water injection system (hereinafter referred to as LPCI) coupling and an overhang (hereinafter referred to as overhang) to a shroud in a reactor pressure vessel. Even if
The present invention relates to an in-reactor inspection device capable of performing a detailed inspection around a jet pump and the outer surface of a shroud.

[0002]

2. Description of the Related Art FIG. 13 is a cross-sectional view showing a state of a boiling water reactor during regular inspection. As shown in FIG. 13, when inspecting the reactor internals at the time of periodic inspection, an RPV lid, a steam dryer, not shown, which is installed above the reactor pressure vessel (hereinafter referred to as RPV) 1, And the steam separator has been removed, and various inspection tools can be accessed inside the furnace. A fuel exchanger 2 is installed above the RPV 1 to facilitate the operation of these inspection tools.

At the time of periodic inspection, the RPV 1 has a cylindrical shroud 3, a core 4 housed in the shroud 3, and the like.
An upper lattice plate 6 for supporting the upper part of the fuel assembly 5 loaded in the core 4, a core support plate 7 for supporting the lower end of the fuel assembly 5, and a jet pump for forcibly sending the coolant to the core 4. Remaining reactor internal structures such as 8 remain in the installed state.

Further, depending on the form of the reactor, an LPCΙ coupling 9 is installed above the shroud 3 in order to replenish cooling water into the reactor in an emergency.
The coupling 9 is a structure that closes the annulus portion above the shroud 3.

In order to inspect the reactor internal structure, an underwater TV camera is usually hung from above the refueling machine 2 to bring it closer to the inspection control point, and its appearance is photographed to check for any abnormality. . At this time, if an abnormal portion is confirmed, an ultrasonic flaw detection (hereinafter referred to as UT) sensor, an eddy current flaw detection (hereinafter referred to as ECT).
It is considered that a device provided with a sensor such as a sensor such as a non-destructive inspection means is accessed from above the refueling machine 2 as in the case of the above-mentioned underwater TV camera to perform an additional inspection to check the quality of the portion.

[0006]

As described above, the jet pump 8 for the nuclear reactor internal structure is installed in the annulus portion between the RPV 1 and the shroud 3 to force the cooling water in the RPV 1 to circulate. It is a structure and 1 by law
It is obligatory to perform a full visual inspection in 0 years. Similarly, by law, it is obligatory to perform a visual inspection, such as brackets attached to the RPV1 wall surface by welding. Among these, the monitoring test piece support bracket 10 and the jet pump riser brace 8a. Is still located in the annulus section.

Although the shroud 3 itself is not required to be inspected by law, it is a cylinder for accommodating the fuel assembly 5 and is the structure closest to the fuel. Therefore, it is proposed in each plant to confirm whether or not it is susceptible to the influence of the above and, therefore, whether it is damaged by this influence.

By the way, the LP which is the above-mentioned reactor internal structure
When a structure that covers the upper space of the annulus portion on the jet pump 8 such as the C-coupling 9 is installed, or due to the presence of the shroud overhang, the underwater T that is normally used in the lower portion of the annulus portion.
It was difficult to access various inspection tools such as the V camera, and detailed inspection of these parts was almost impossible.

The present invention has been made in consideration of the above-mentioned circumstances, and makes it possible to access various inspection jigs and tools to the annulus portion while avoiding a structure such as an LPCΙ coupling attached to the upper part of the shroud or a shroud overhang. It is an object of the present invention to provide a nuclear reactor inspection device capable of performing the inspection.

[0010]

In order to solve the above-mentioned problems, the first aspect of the present invention is to provide a shroud installed in a reactor pressure vessel with a low-pressure water injection system coupling and an overhang portion. A low pressure water injection system coupling and an in-reactor inspection device for inspecting the annulus portion below the overhang portion, such as a jet pump installed between the reactor pressure vessel and a shroud and the shroud upper structure. A guide mechanism for positioning an inspection head, which is positioned on the internal structure of the furnace and equipped with various inspection jigs, for accessing the annulus portion, a swivel mechanism for swiveling the inspection head in the annulus portion, and the annulus. And a moving mechanism for moving the inspection head within the unit.

According to a second aspect of the present invention, in the in-reactor inspection apparatus according to the first aspect, a telescopic plate for positioning the vertical position of the inspection head is provided.

According to a third aspect of the present invention, in the in-reactor inspection apparatus according to the first aspect, a propulsion mechanism interlocking with a swivel mechanism and a moving mechanism is attached to the inspection head.

A fourth aspect of the present invention is the in-reactor inspection apparatus according to the first aspect, wherein the inspection head is provided with a suction mechanism.

According to a fifth aspect of the present invention, in the in-reactor inspection apparatus according to the first aspect, the inspection head is provided with a pressing mechanism for positioning the inspection head.

A sixth aspect of the present invention is the in-reactor inspecting apparatus according to the fourth or fifth aspect, wherein a wall surface moving mechanism is attached to the inspection head.

According to a seventh aspect, in the in-reactor inspection apparatus according to the first aspect, the base of the inspection head is a fixed base,
At least one of an underwater VV camera for visual inspection, an ultrasonic flaw detection sensor for volume inspection, and an eddy current flaw detection sensor for surface inspection can be attached to this fixing base.

According to an eighth aspect of the present invention, in the in-reactor inspection apparatus according to the first aspect, the inspection head is an underwater TV camera for visual inspection, and a plurality of illuminance-adjustable devices are provided around the underwater TV camera. It is characterized by the installation of lighting equipment.

According to a ninth aspect of the present invention, in the in-reactor inspection apparatus according to the eighth aspect, a brush, a water jet nozzle, and a suction nozzle are provided in the vicinity of the underwater TV camera.

According to a tenth aspect of the present invention, in the in-reactor inspection apparatus according to the eighth aspect, a water jet nozzle for spraying water toward a lens portion or a mirror portion of the underwater TV camera is provided in the vicinity of the underwater TV camera. Characterize.

According to an eleventh aspect of the present invention, in the in-reactor inspection apparatus according to the first aspect, any one of a magnetic sensor for detecting an amount of γ-ferrite and an eddy-current flaw detecting sensor for detecting an eddy current influenced by the amount of γ-ferrite is used in the inspection head. One of the features is that one is attached.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged perspective view showing the installed state of the first embodiment of the in-reactor inspection device according to the present invention. As shown in FIG. 1, a jet pump 8 which is an internal reactor structure is installed in the annulus portion between the RPV and the shroud 3, and the jet pump 8 forcibly circulates the cooling water in the RPV. The jet pump riser brace 8a is attached to the RPV wall surface by welding, and two hanging ears (upper structure) 8b are provided on the upper portion.

On the upper part of the shroud 3, an LPC I coupling 9 for replenishing the cooling water in the reactor in case of emergency is installed so as to close the upper space of the annulus part on the jet pump 8. Similarly, shroud 3
A shroud overhang is provided in the upper part of the so as to close the upper space of the annulus part on the jet pump 8.

On the other hand, the in-reactor inspection device 20 has an operation pole 21 operated by a fuel exchanger, and a guide mechanism positioned at the lower end of the operation pole 21 by seating on the hanging ear 8b of the jet pump 8. The seating portion 22 is attached. Further, above the seating portion 22 of the operation pole 21, a hook 23 is attached as a guide mechanism which is positioned by being hooked on the upper structure of the shroud 3. An arm extension / contraction mechanism 24 as a moving mechanism is attached to the seating portion 22, and the arm 25 can be extended / contracted by operating the arm extension / contraction mechanism 24.

The control cable 26 laid along the operation pole 21 is guided by the hook 23 and the arm 25, and various inspection jigs and tools are mounted on the lower end thereof to inspect the periphery of the jet pump 8 and the outer peripheral surface of the shroud 3. The inspection head 27 is suspended. Further, a swivel mechanism 28 that swivels the arm 25 to move the inspection head 27 to the upper portion of the inspection target portion is disposed above the seating portion 22.

Next, the operation of this embodiment will be described.

In this embodiment, the LP is provided above the shroud 3.
At the time of periodic inspection in a reactor in which structures such as the C coupling 9 and the shroud overhang are installed, the in-reactor inspection device 20 causes the jet pump and the shroud located in the annulus between the RV and the shroud 3 to be inspected. Check the outer peripheral surface.

First, the RPV to be removed by the regular periodic inspection
R after removing the lid, steam dryer, and steam separator
Inspecting device 20 inside the reactor
Is hung from the refueling machine using the operation pole 21. In this case, the inspection head 27 is suspended from the refueling machine while avoiding interference with structures such as the LPCI coupling 9 and the shroud overhang.
Then, the seating portion 22 is seated on the hanging ear 8b of the jet pump 8, and at the same time, the hook 23 is hooked on the upper structure of the shroud 3 to lower the inspection head 27 to the level of the inspection target portion. As a result, the in-reactor inspection device 20 is positioned and the fall is prevented.

After the in-reactor inspection device 20 is installed in this manner, when performing the inspection, the swivel mechanism 28 and the arm extension / contraction mechanism 24 are operated to move the inspection head 27 to the upper portion of the inspection target area. The control cable 26 connected to the head 27 is operated to move the inspection head 27 up and down or rotate to position the inspection head 27 at the inspection target portion, and then the target inspection is performed.

Here, a drive signal is sent to the turning mechanism 28 and the arm extension / contraction mechanism 24 from a console installed on an operation floor (not shown) via, for example, a signal line provided in the operation pole 21.

As described above, according to this embodiment, the seating portion 22 is positioned on the hanging ear 8a of the jet pump 8 in the vicinity of the inspection location, and at the same time, the hook 23 is hooked to the internal structure such as the upper structure of the shroud 3. After the inspection head 27 is lowered to the level of the inspection target position, the swivel mechanism 28 and the arm extension / contraction mechanism 24 position the inspection head 27 at the inspection target position, and the target inspection is performed to access the inspection head 27. Even when a structure such as the LPC Ι coupling 9 or shroud overhang, which is an obstacle, is installed on the route, it is possible to perform a highly accurate inspection on the structure located in the annulus part with a relatively simple device. .

In this embodiment, the seating portion 22 is positioned on the hanging ear 8a of the jet pump 8, but it may be positioned on the upper structure of the jet pump 8 other than this.

FIGS. 2A and 2B are a front view and a side view showing an inspection head in a second embodiment of the in-reactor inspection device according to the present invention. It should be noted that the same or corresponding parts as those of the first embodiment will be described with the same reference numerals. The same applies to each of the following embodiments.

In the first embodiment, since the inspection head 27 is simply suspended by the control cable 26, the inspection head 27 is shaken and is difficult to stabilize, so it may take a long time for the inspection.

Therefore, in the second embodiment, a stretchable plate 29 having rigidity is arranged between the arm 25 of the stretchable arm mechanism 24 and the inspection head 27. The extendable plate 29 has a multi-stage structure, both ends of which are fixed to the arm 25 and the inspection head 27, respectively, and is configured to expand and contract following the raising and lowering operation of the inspection head 27.

A head rotating mechanism 30 for rotating the inspection head 27 is provided on the fixed portion of the inspection head 27. The head rotation mechanism 30 includes an inspection head clamp 31 that holds the inspection head 27, a head rotation gear 32 fixed to the inspection head clamp 31,
A drive gear 33 that meshes with the head rotation gear and a head rotation motor 34 that rotationally drives the drive gear 33 are provided.

When the head rotation motor 34 is operated, the drive gear 33 rotates, and the rotational force of the drive gear 33 is applied to the head rotation gear 32 and the inspection head clamp 31.
The inspection head 27 is rotated via the. As a result, the direction of the inspection head 27 can always be oriented in the correct direction with respect to the inspection target portion.

As described above, according to the second embodiment, since the elastic expansion / contraction plate 29 is disposed between the arm 25 of the expansion / contraction arm mechanism 24 and the inspection head 27, the shake due to inertia is eliminated, and the inspection is performed. Stable positioning of the head 27 is possible.

3A and 3B are a front view, a side view, and FIGS. 4A, 4B, and 4C showing an inspection head in a third embodiment of the in-reactor inspection device according to the present invention. 8] is a perspective view showing an operating state of the inspection head of the third embodiment.

In the second embodiment, the jet pump 8
When inspecting a narrow part between the shroud 3 and the RPV, or a part lower than the overhang part such as the lower body of the shroud 2, the telescopic plate 29 may interfere, which may reduce accessibility. .

Therefore, as shown in FIGS. 3 (A) and 3 (B), the inspection head 27 suspended by the control cable 26 has the propulsion mechanism 35 attached to both the upper and lower sides thereof. These propulsion mechanisms 35 generate a propulsion force in conjunction with the operations of the swivel mechanism 28 and the arm extension / contraction mechanism 24, and assist movement of the inspection head 27 as shown in FIGS. 4 (A), (B), and (C). Also, the posture control is performed to improve the motility in the state of being suspended by the control cable 21.

As described above, according to the third embodiment, the inspection head 27 is provided with the propulsion mechanism 35 that generates the propulsive force in conjunction with the operations of the turning mechanism 28 and the arm extension / contraction mechanism 24 as described above.
Since the movements of the swing mechanism 28 and the arm extension / contraction mechanism 24, which are the upper operation mechanism, coincide with the movements of the inspection head 27, the extra moment is not generated, and therefore the inspection head 27 is attached. You can move smoothly without shaking.

FIGS. 5A and 5B are a front view and a side view showing an inspection head in a fourth embodiment of the in-reactor inspection apparatus according to the present invention.

When inspecting the internal structure of the reactor when the appearance is to be confirmed using an underwater TV camera, the underwater TV camera should be appropriately brought close to the object to be inspected, and the focus mechanism of the camera should be used to make a proper adjustment. Good. However, UT sensor and E
When performing the inspection by the CT sensor, it is necessary to accurately position the inspection head 27 at the inspection target portion.

Therefore, as shown in FIGS. 5 (A) and 5 (B), the inspection head 27 suspended by the control cable 26 has the propulsion mechanisms 35 attached to the upper and lower sides thereof, respectively. Adsorption mechanism 36 is installed adjacently. The suction mechanism 36 is equipped with a suction pad 37 for sucking and fixing the suction target portion.

Therefore, the inspection head 27 approaches the inspection target location by the propulsion mechanism 35 or the like after approaching the inspection target location by the swivel mechanism 28 or the arm extension / contraction mechanism 24,
By operating the suction mechanism 36, the suction pad 37 is sucked and fixed to the inspection target portion. As a result, the inspection head 27 is accurately positioned and stable inspection is possible.

As described above, according to the fourth embodiment, the suction mechanism 36 is attached to the inspection head 27, and the inspection head 2
By adsorbing No. 7 to the shroud 3 or the RPV wall surface that is the inspection target site, a stable inspection can be performed.

FIGS. 6A and 6B are side views showing an inspection head in a first modification of the fourth embodiment of the in-reactor inspection apparatus according to the present invention. In this modification, a stopper 38 is fixed adjacent to each propulsion mechanism 35, while a pressing cylinder 39 is provided on the back surface of the inspection head 27.
A pressing arm 40 that is horizontally pushed out by the operation of the pressing cylinder 39 is provided.

Therefore, on the back surface of the inspection head 27,
As shown in FIG. 6A, the pressing arm 40 is attached in a folded state, and after the inspection head 27 is brought close to the inspection target portion, the pressing cylinder 39 is operated to move the pressing arm 40 in the horizontal direction. By pushing the structure to the opposite position to the inspection target,
As a result, the inspection head 27 is pressed against the inspection target area,
Position.

As described above, according to the first modification, the pressing cylinder 39 and the pressing arm 40 that is horizontally pushed out by the operation of the pressing cylinder 39 are arranged on the back surface of the inspection head 27. Inspection head 27
Is accurately positioned, and stable inspection is possible.

FIG. 7 is a perspective view showing an inspection head in a second modification of the fourth embodiment of the in-reactor inspection device according to the present invention.

In the fourth embodiment and the first modified example thereof, it is necessary to carry out the inspection while repositioning the inspection target portion having a length such as the welded portion of the shroud 3 a plurality of times. It was

Therefore, in the second modification, a moving mechanism is added to the end of the positioning mechanism. That is,
In the second modification, as shown in FIG. 7, a moving mechanism 42 as a wall surface moving mechanism is attached to an end of a positioning mechanism section 41 having a propulsion mechanism 35 and a suction mechanism 36, and the moving mechanism 42 is operated. Thereby, the guide portion 43 is expanded and contracted. The inspection head 27 is fixed to the tip of the guide portion 43.

Therefore, in the second modification, after the inspection head 27 is positioned, the moving mechanism 42 attached to the positioning mechanism portion 41 is operated to extend the guide portion 43 and extend along the wall surface.
The inspection is carried out while moving.

As described above, according to the second modified example, as in the fourth embodiment and the first modified example thereof, the inspection is performed while repositioning the inspection target portion having a length a plurality of times. Instead, continuous inspection within a certain range is possible.

FIGS. 8A and 8B are a plan view and a front view showing the fixing base of the inspection head in the fifth embodiment of the in-reactor inspection device according to the present invention.

In the in-reactor inspection apparatus of each of the above-mentioned embodiments, it is necessary to design the inspection head 27 for each intended inspection method and prepare as many inspection heads 27 as necessary according to the purpose. There was also a lot of waste in terms of setup time.

Therefore, in the fifth embodiment, as shown in FIG.
As shown in (B), the base of the inspection head 27 is a fixing base 44, and inspection sensors and the like are attached to the fixing base 44 as needed.

That is, the inspection head 27 in this embodiment is a plate-shaped fixing base 44 in which fixing bolt holes 44a are regularly arranged for mounting each inspection sensor, and the fixing bolt holes 44a are provided in the fixing head holes 44a. As many inspection sensors as necessary, such as an underwater V camera for visual inspection, a UT sensor for volume inspection, and an ECT sensor for surface layer inspection, which are modularized according to the inspection purpose, are attached. A pressing spring 45 is attached to the back surface of the fixing base 44.

As described above, according to the fifth embodiment, it is not necessary to prepare the inspection head 27 as many times as necessary according to the purpose, most of the apparatus parts can be shared, and the setup change can be performed quickly and the number of times can be changed. Can also be reduced.

FIG. 9 is a front view showing an underwater TV camera of the sixth embodiment of the in-reactor inspection device according to the present invention.

As described above, the inspection of the reactor internal structure is usually an indirect visual inspection (VT) using an underwater TV camera.
However, if an image that seems to be defective is confirmed by this inspection, it will be confirmed using various means. However, before carrying out this confirmation, it is desirable to perform detailed confirmation by VT using other inspection means as much as possible, and sufficiently carry out the primary judgment as to whether or not there is a defect. Therefore, in the sixth embodiment, whether or not there is a defect is confirmed in detail during VT.

That is, in the sixth embodiment, as shown in FIG. 9, a plurality of underwater lighting fixtures 51 are attached around the underwater TV camera 50, and each underwater lighting fixture 51.
Are configured so that they can be turned on or adjusted independently.

Therefore, during the normal inspection, all of these underwater lighting devices 51 are adjusted to proper illuminance and turned on, and the presence or absence of defects is confirmed. In the unlikely event that an image that seems to be a defect is confirmed, these underwater lighting devices 51 are individually turned on, and the illuminance adjustment is performed from the insufficient illuminance state to the excessive illuminance state to confirm the defect at the inspection target location. Change the direction and strength of light that seems to be projected on the image part.

As a result, if the image is not a pattern but a discontinuity in shape, the shadow changes depending on the direction of the light. By confirming this change, the pattern on the clad can be confirmed. It is possible to easily judge whether the image is a video image with a high possibility of a defect.

FIG. 10 is a front view showing an underwater TV camera of the seventh embodiment of the inspection system for a nuclear reactor according to the present invention. In the seventh embodiment, the clad is removed simultaneously with the inspection.

By the way, on the surface of the structure in the nuclear reactor, many clads adhere and deposit as the operation period increases. In some cases, the cladding may obscure the fine defects to make detection difficult, or may affect the detection performance in the inspection of the ECT sensor or the like. Therefore, if necessary, polish the surface to be inspected,
This clad must be removed. Whether or not it is necessary to remove the clad is determined by checking the clad adhesion state with the underwater TV camera 50 or the like. However, it is quite possible to perform setup and realignment after determining that clad removal is necessary. Will be a loss of work time.

Therefore, in the seventh embodiment, as shown in FIG. 10, a clad removing tool such as a brush 52, a water jet nozzle 53, and a suction nozzle 54 is provided in the vicinity of the underwater TV camera 50 for performing VT. When it is judged that the clad needs to be removed in V Τ, immediately activate these clad removing tools, and
It is possible to reliably remove the clad that interferes with the inspection while checking the clad removal status with the camera 50.
As a result, it is possible to directly access the material surface of the inspection target site without the influence of the clad.

FIG. 11 is a front view showing an underwater TV camera of an eighth embodiment of the inspection system for a nuclear reactor according to the present invention.

If the clad is removed as in the seventh embodiment, or if the inspection head 27 moves while rubbing the inspection target without removing the clad,
The soft clad adhering to the material surface floats in the water, and this often adheres to the lens portion or mirror portion of the underwater TV camera 50 to make the image to be confirmed unclear. In this case, it was necessary to lift the underwater TV camera 50 and clean the attached clad when the image became unclear to some extent.

Therefore, in the eighth embodiment, water is sprayed from the water jet nozzle 53 toward the lens portion 55 and the mirror portion 56 of the underwater TV camera 50 to blow off the clad.

That is, the water jet nozzle 53 is provided in the vicinity of the underwater TV camera 50, and water is constantly sprayed toward the lens portion 55 and the mirror portion 56 of the underwater TV camera 50. This causes most of the floating cladding to be swept away by the water stream. A part of the clad rides on the water flow and collides with the lens part 55 and the mirror part 56, and once adheres, it is immediately washed and washed by the water flow of the water jet, which does not adversely affect the image. Absent.

As described above, according to the eighth embodiment, the underwater T
It is not necessary to pull up the V camera 50 and clean the attached clad, and it is possible to perform VT with a clear image at all times.

FIG. 12 is a front view showing an inspection head of a ninth embodiment of the in-reactor inspection device according to the present invention.

The inspection using the apparatus according to each of the above-described embodiments is mainly applied to a portion where it is feared that an excessive stress is applied or a portion where a defect such as a welded portion is likely to occur. .

By the way, the heat-affected zone of the weld zone is
Since it is a portion where C (stress corrosion cracking) is likely to occur, it is desirable to inspect it in detail, but it is often found that the surface of this welded portion is processed smoothly during the manufacture of the structure, and therefore inspection is performed. It may be difficult to accurately determine the welding position during implementation.

Generally, γ-ferrite is precipitated in the welded portion, and therefore, the amount of ferrite in the welded portion is larger than that in the base metal portion.

Therefore, in the eighth embodiment, the inspection head 2
7, a magnetic sensor 57 for detecting the amount of γ-ferrite,
Or E to detect eddy current affected by the amount of γ-ferrite
The CT sensor 58 is attached. Thus, the magnetic sensor 57 or the ECT sensor 58 is scanned in the vicinity of the inspection target position before the inspection is performed, and the position where the ferrite amount changes is measured, whereby the welded position can be accurately determined.

[0079]

As described above, according to the first aspect of the present invention.
According to the above, the inspection head, which is positioned on the reactor internals such as the jet pump and the shroud superstructure installed between the reactor pressure vessel and the shroud, and which is equipped with various inspection tools is installed in the annulus part. By providing a guide mechanism for accessing, a swivel mechanism for swiveling the inspection head in the annulus portion, and a moving mechanism for moving the inspection head in the annulus portion, the inspection head which has been conventionally difficult to inspect Even when the obstacles such as LPCΙ coupling and shroud overhang are installed on the access route, highly accurate inspection can be easily performed on the structure located in the annulus with a relatively simple device. Becomes

According to the second aspect, by providing the telescopic plate for positioning the vertical position of the inspection head,
The shake due to inertia disappears, and stable positioning of the inspection head becomes possible.

According to the present invention, since the inspection head is equipped with the propulsion mechanism interlocking with the turning mechanism and the moving mechanism, an extra moment is not generated, and the inspection head can be moved smoothly without being shaken. Becomes

According to the fourth aspect, since the inspection head is provided with the suction mechanism, the inspection head is adsorbed to the shroud or the RPV wall surface which is the inspection target portion, so that the inspection head is accurately positioned and stable inspection is performed. It will be possible.

According to the fifth aspect, since the inspection head is provided with the pressing mechanism for positioning the inspection head, the inspection head is accurately positioned and stable inspection can be performed.

According to the sixth aspect, the wall surface moving mechanism is attached to the inspection head, so that the inspection can be performed within a predetermined range without performing the inspection while repositioning the inspection target portion having a length for a plurality of times. Continuous inspection is possible.

According to the present invention, the base of the inspection head is used as a fixing base, and the fixing base has an underwater VV camera for appearance inspection, an ultrasonic flaw detection sensor for volume inspection, and an eddy current flaw detection sensor for surface layer inspection. By making it possible to attach at least one of the above, it is not necessary to prepare as many inspection heads as necessary according to the purpose, most of the device parts can be shared, setup change can be done quickly, and the number of times can be reduced. Is possible.

According to the present invention, the inspection head is an underwater TV camera for visual inspection, and a plurality of luminaires each capable of adjusting the illuminance are attached around the underwater TV camera. If the presence or absence of images is confirmed by checking the presence or absence of the defects, these lighting fixtures are individually turned on, and the illuminance adjustment is performed from the insufficient illuminance state to the excessive state to confirm the inspection target location. Change the direction and intensity of light that hits the image area, which is considered to be a defect.
As a result, if the image is not a pattern but a discontinuity in the shape, the shadow changes depending on the direction of the light. It is possible to easily judge whether the image has a high possibility of a defect.

According to the ninth aspect, the brush, the water jet nozzle, and the suction nozzle are provided in the vicinity of the underwater TV camera, so that the clad which interferes with the inspection can be checked while confirming the clad removal state with the underwater TV camera. Can be reliably removed. As a result, it is possible to directly access the material surface of the inspection target site without the influence of the clad.

According to the tenth aspect, the water jet nozzle for spraying water toward the lens portion and the mirror portion of the underwater TV camera is provided in the vicinity of the underwater TV camera.
It is no longer necessary to pull up the device and clean the attached clad, and indirect visual inspection can always be performed with a clear image.

According to the eleventh aspect, the inspection head is equipped with either a magnetic sensor for detecting the amount of γ-ferrite or an eddy current flaw detection sensor for detecting an eddy current affected by the amount of γ-ferrite. It is possible to accurately determine the position of the welded portion by scanning the vicinity of the inspection target position and measuring the position where the ferrite amount changes.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing an installed state of a first embodiment of an in-reactor inspection device according to the present invention.

2A and 2B are a front view and a side view showing an inspection head in a second embodiment of the in-reactor inspection device according to the present invention.

3 (A) and 3 (B) are a front view and a side view showing an inspection head in a third embodiment of the in-reactor inspection device according to the present invention.

4A, 4B, and 4C are perspective views showing the operating state of the inspection head of the third embodiment.

5 (A) and 5 (B) are a front view and a side view showing an inspection head in a fourth embodiment of the in-reactor inspection device according to the present invention.

6A and 6B are side views showing an inspection head in a first modified example of the fourth embodiment of the in-reactor inspection device according to the present invention.

FIG. 7 is a perspective view showing an inspection head in a second modified example of the fourth embodiment of the in-reactor inspection device according to the present invention.

8A and 8B are a plan view and a front view showing a fixing base of an inspection head in a fifth embodiment of the in-reactor inspection device according to the present invention.

FIG. 9 is a front view showing an underwater TV camera of a sixth embodiment of the in-reactor inspection device according to the present invention.

FIG. 10 is a front view showing an underwater TV camera of a seventh embodiment of the in-reactor inspection device according to the present invention.

FIG. 11 is a front view showing an underwater TV camera of an eighth embodiment of the in-reactor inspection device according to the present invention.

FIG. 12 is a front view showing an inspection head of a ninth embodiment of the in-reactor inspection device according to the present invention.

FIG. 13 is a cross-sectional view showing a state of the boiling water nuclear reactor under regular inspection.

[Explanation of Codes] 1 Reactor Pressure Vessel 2 Fuel Exchanger 3 Shroud 8 Jet Pump 9 LPCΙ Coupling 20 Reactor Inspector 21 Operation Pole 22 Seating Part (Guide Mechanism) 23 Hook (Guide Mechanism) 24 Arm Expansion Mechanism (Movement) 25 arm 26 control cable 27 inspection head 28 swivel mechanism 29 telescopic plate 30 head rotation mechanism 31 inspection head clamp 35 propulsion mechanism 36 suction mechanism 37 suction pad 38 stopper 39 pressing cylinder 40 pressing arm 41 positioning mechanism section 42 moving mechanism 43 guide Part 44 Fixing Base 50 Underwater TV Camera 51 Underwater Lighting Fixture 52 Brush 53 Water Jet Nozzle 54 Suction Nozzle 55 Lens Part 56 Mirror Part 57 Magnetic Sensor 58 ECT Sensor

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G21C 17/00 GDBF

Claims (11)

[Claims] 1. A low pressure water injection system coupling and an overhang portion are provided in a shroud installed in a reactor pressure vessel,
An in-reactor inspection device that inspects the low-pressure water injection system coupling and the annulus portion below the overhang portion, such as a jet pump installed between the reactor pressure vessel and a shroud and the shroud upper structure. A guide mechanism that is positioned on the internal structure of the furnace and that allows an inspection head having various inspection jigs and tools to access the annulus portion, a swivel mechanism that swivels the inspection head within the annulus portion, and the annulus. And a moving mechanism for moving the inspection head in a unit. 2. The in-reactor inspection apparatus according to claim 1, further comprising a telescopic plate for positioning the vertical position of the inspection head. 3. The in-reactor inspection apparatus according to claim 1, wherein the inspection head is provided with a propulsion mechanism that interlocks with a turning mechanism and a moving mechanism. 4. The in-reactor inspection device according to claim 1, wherein the inspection head is provided with a suction mechanism. 5. The in-reactor inspection apparatus according to claim 1, wherein the inspection head is provided with a pressing mechanism for positioning the inspection head. 6. The in-reactor inspection apparatus according to claim 4 or 5, wherein a wall surface moving mechanism is attached to the inspection head. 7. The in-reactor inspection apparatus according to claim 1, wherein the base of the inspection head is a fixing base, and the fixing base has an underwater VV camera for appearance inspection, an ultrasonic flaw detector for volume inspection, and a surface layer. An in-reactor inspection device, wherein at least one of the eddy current flaw detection sensors for part inspection can be attached. 8. The in-reactor inspection apparatus according to claim 1, wherein the inspection head is an underwater TV camera for visual inspection, and a plurality of luminaires each capable of adjusting illuminance are provided around the underwater TV camera. In-reactor inspection device characterized by being installed. 9. The in-reactor inspection device according to claim 8, wherein a brush, a water jet nozzle, and a suction nozzle are provided in the vicinity of the underwater TV camera. 10. The in-reactor inspection device according to claim 8, wherein a water jet nozzle for spraying water toward a lens portion or a mirror portion of the underwater TV camera is provided in the vicinity of the underwater TV camera. In-reactor inspection device. 11. The in-reactor inspection apparatus according to claim 1, wherein the inspection head is provided with one of a magnetic sensor for detecting the γ-ferrite amount and an eddy current flaw detection sensor for detecting an eddy current affected by the γ-ferrite amount. In-reactor inspection device characterized by being installed.