JP2001235579A - Underwater inspection device in water storage structure for nuclear power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously carry out decontamination and inspection work in water without draining pool water in a water storage structure such as an temporary equipment placing pool. SOLUTION: An inspection mechanism part 15 and a decontamination mechanism part 16 are integrally built in a case 14 in the pool water 2 in the water storage structure 1. The decontamination mechanism part 16 has an injection nozzle 21 and a suction nozzle 24. The injection nozzle 21 is supplied with high pressure water from a high pressure water supply tank 13 through a high pressure hose 22, and the inner surface and bottom face of the water storage structure 1 are decontaminated with the high pressure water. The quality of decontamination is judged by the inspection mechanism part 15. Decontaminated water sucked by the suction nozzle 24 is passed through a cyclone separator 26 and a filter 9 to eliminate solid components contained in the water. The inspection mechanism part 16 is provided with a two-dimensional general-purpose camera, a three dimensional camera, and a probe of an ultrasonic detector or a vortex flow detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open tank, a storage tank, a spent fuel pool of a reactor building, an equipment storage pit, a sump pit, and a suppression pool of a waste storage facility installed as a water storage structure in a nuclear power plant. The present invention relates to an underwater inspection device in a storage structure of a nuclear power plant.

[0002]

2. Description of the Related Art At a nuclear power plant, a spent fuel pool of a reactor building where high-dose equipment is stored, an equipment storage pit, an open tank of a waste storage facility where radioactive deposits are stored, There are water storage structures such as storage tanks, sump pits and suppression pools. Of these, the tanks, pits, and the like are provided with a metal plate lining, and the metal plate lining prevents leakage.

[0003] In these lining storage tanks, storage equipment or radioactive solid waste is moved, and the metal plate lining may be damaged due to external factors such as impact or dropping during the movement, and cracks may occur. . In addition, there is a possibility that corrosion or the like may occur due to the number of years of use or the aging life.

[0004]

Conventionally, in order to carry out inspection of these lining storages, water is once taken out of the lining storage tank, and then visually inspected (hereinafter referred to as VT) and liquid penetration inspection (hereinafter referred to as VT). Hereafter, it was necessary to carry out an ultrasonic flaw detection test (hereinafter, referred to as UT) and an ultrasonic inspection test (hereinafter, referred to as UT). For this reason, since there is no water layer to shield radiation, there is an unsuitable problem that the exposure dose to the worker is extremely large.

[0005] On the other hand, a method of performing VT by using an underwater television camera without carrying out the stored water from the lining storage tank has been conventionally performed. However, radioactive sediments (hereinafter referred to as water scale = cladding) and debris (wires, bolts, nuts, etc.) are accumulated, and the water storage is turbid due to water scale, and it is possible to determine whether the defect causes leakage. Finding the smallest defect is extremely difficult,
In addition, there is a problem that an inspection operation requires a long time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and detects a leak defect or an extremely small defect on the bottom surface of a lining storage tank by remote control from the surface of the water without discharging the water stored in the lining storage tank. To provide an underwater inspection device such as an open tank of a nuclear power plant.

[0007]

The invention according to claim 1 is
A movable removal unit that is installed in the water in the water storage structure and includes a spray nozzle that sprays high-pressure water toward the inner surface or floor of the water storage structure, and a high-pressure water supply system that supplies high-pressure water to the spray nozzle. It is characterized by comprising a dyeing mechanism and a movable inspection mechanism for detecting a defect on the inner surface or floor of the water storage structure.

According to the present invention, in a water storage structure such as an open tank, a pool, or a pit of a nuclear power plant, an injection nozzle for injecting water toward the inner surface thereof, a high-pressure pump for supplying water, and a high-pressure water supply The inspection mechanism for inspecting the tank, the high-pressure hose, and the floor enables decontamination and inspection without draining the pool water. In addition, decontamination and inspection of the inner surface and floor surface can be performed with almost no radiation exposure dose.

According to a second aspect of the present invention, the decontamination mechanism and the inspection mechanism are incorporated into a housing and integrated, and a suction nozzle is attached to the decontamination mechanism, and a downstream side of the suction nozzle. , A cyclone separator and a filter are provided, and a return line connected to a drainage hose in the water storage structure is provided downstream of the filter.

According to the present invention, in the decontamination mechanism unit integrated with the inspection mechanism unit, a suction pump for sucking water from the open tank, pool, and pit and a solid component contained in the sucked water are collected. The cyclone separator, the collection tank, and a filter and a drainage hose provided downstream of the cyclone separator can perform inspection without cladding and dust, thereby greatly improving the inspection accuracy. In addition, it is possible to collect refuse (solids such as wire, bolts, and nuts). Further, the purified water filtered by the return line can be returned to the water storage structure and reused.

The invention according to claim 3 is characterized in that a probe of a two-dimensional general-purpose camera, a three-dimensional camera, an ultrasonic flaw detector or an eddy current flaw detector is attached to the inspection mechanism. According to the present invention, a two-dimensional general-purpose camera, a three-dimensional camera, an ultrasonic flaw detector (UT), and an eddy current flaw detector (ECT) can be used to determine whether a defect causes leakage or to find a very small defect.

The invention according to a fourth aspect is characterized in that a moving mechanism capable of moving the probe in X and Y directions is attached to the inspection mechanism. According to the invention,
Ultrasonic flaw detector (UT) and eddy current flaw detector (ECT) have a moving mechanism that can move the probe in the X and Y directions, making it possible to remotely measure the dimensions of defects etc. Inspection work can be easily performed in a short time.

[0013]

1 and 2 (a) and 2 (b), an embodiment of the underwater inspection device in a water storage structure of a nuclear power plant according to the present invention will be described. FIG. 1 is an overall configuration diagram of the present embodiment. FIG. 2A is a side view of the inspection mechanism in FIG. 1, and FIG. 2B is a bottom view of FIG. 2A.

In FIG. 1, reference numeral 1 denotes a water storage structure installed in a reactor building of a nuclear power plant. This water storage structure 1 refers to a structure in which water is stored, such as a fuel storage pool, a temporary storage pool for equipment, an open tank, a suppression chamber, a reactor well, and the like. The pool water 2 is stored inside, including a metal plate lining made of steel or the like.

Reference numeral 3 denotes an operation floor in the reactor building. On the operation floor 3, an ultrasonic flaw detector (UT), an eddy current flaw detector (ETC) monitor 4, a control device 5,
A television monitor 6, a collection tank shielding container 8 surrounding the collection tank 7, a filter shielding container 10 surrounding the filter 9, a suction pump 11, a high pressure pump 12, and a high pressure water supply tank 13 are provided.

Reference numeral 14 denotes a housing, in which an inspection mechanism 15 and a decontamination mechanism 16 are integrated into the housing 14, and the lower surface of the housing 14 is open. . Housing
The lower surface of 14 is sealed with the bottom surface of the water storage structure 1 by a rubber packing 17. Hanging ears 18 are attached to the upper surface of the casing 14, and the hanging ears 18 can be lifted and suspended by the hanging hooks 20 of the overhead crane through the hanging wires 19. By moving an overhead crane (not shown) to which the hanging hooks 20 are connected, the inspection mechanism 15 and the decontamination mechanism 16 can be moved to arbitrary locations.

Here, the decontamination mechanism 16 will be described.
An injection nozzle 21 is provided in the housing 14 of the decontamination mechanism 16, and the injection nozzle 21 is installed obliquely from an opening provided on the side of the housing 14 of the decontamination mechanism 16. Structure 1
It is configured to inject high-pressure water toward the bottom surface or side surface.

A high-pressure hose 22 is connected to the injection nozzle 21, and the other end of the high-pressure hose 22 is connected to the high-pressure pump 12. The high-pressure pump 12 sucks stored water 23 stored in a high-pressure water supply tank 13 and
It is configured to supply high-pressure water to the injection nozzle 21 through 22.

A suction nozzle is provided on the side of the decontamination mechanism 16.
The suction nozzle 24 is provided with a decontamination mechanism 16.
And faces the injection nozzle 21. A suction hose 25 is connected to the suction nozzle 24, and the suction pump 11 and the cyclone separator 26 are connected through the suction hose 25.
It is connected to the.

A collecting tank 7 for collecting solid components (number lines, bolts, nuts, etc.) is provided below the cyclone separator 26, and a filter 9 is provided downstream of the cyclone separator 26. The cyclone separator 26 is configured to give a swirling flow to the water sucked from the inside of the decontamination mechanism 16, separate relatively coarse solids contained therein, and collect the solids in the collection tank 7. ing.

The filter 9 is a cyclone separator.
It is configured to filter and collect fine solid components (water scale = cladding, etc.) that could not be collected at 26. The cyclone separator 26 and the filter 9 are accommodated in radiation shielding containers 8 and 10, and the shielding containers 8 and 10 are covered (not shown) to seal the collection tank 7 and the filter 9 therein, and are disposed of. It is configured so that it can be transported to a material processing facility.

A radiation measuring device 2 is provided outside the shielding containers 8 and 10.
7 and 28 are attached, and are configured to sound an alarm when the collected solid component increases and the dose reaches an allowable radiation dose that can be transported to a waste treatment facility. The suction pump 11 is provided between the cyclone separator 26 and the filter 9. After the coarse water contained in the suction water is collected and removed by the cyclone separator 26, the suction pump 11 It is configured to be sucked in.

The high-pressure pump 12 and the suction pump 11 are operated, and the inspection mechanism 15 and the decontamination mechanism 16 can be moved to arbitrary locations by operating the overhead crane along the bottom surface of the water storage structure 1 or the like. it can. In this case, the pool water 2 is kept stored in the water storage structure 1.

The high-pressure water pumped from the high-pressure pump 12 is jetted from an injection nozzle 21. The jet hits the bottom surface of the water storage structure 1, and the pressure separates radioactive deposits and the like. The solid component floats in the water in the decontamination mechanism 16 without diffusing into the water storage structure 1.
The solid components floating in the decontamination mechanism 16 are sucked from the suction nozzle 24 together with the water.

The sucked water is first supplied to a cyclone separator
After flowing into the filter 26, relatively coarse solid components having a large specific gravity are collected and removed, and then sent to the filter 9 to collect and remove fine solid components having a small specific gravity. The water from which all the solid components have been removed is discharged from the return line 29 connected to the downstream side of the filter 9 into the water storage structure 1 through a drainage hose 30 provided with a tip opening in the water storage structure 1.

With the pool water 2 stored in the water storage structure 1, radioactive deposits on the bottom surface of the water storage structure 1 are removed, and the decontamination work of the water storage structure 1 can be performed. Since the radiation is shielded by the water layer, the exposure dose to the worker can be greatly reduced. Since the sediment is removed by spraying high-pressure water, the sediment having a strong adhesive force can be surely separated and removed, and good decontamination is performed.

A cyclone separator 26 is provided on the upstream side, and a filter 9 is provided on the downstream side. Coarse solid components are first separated by the cyclone separator 26 and collected in the collection tank 7, and then fine solid components are filtered by the filter 9. Since the components are removed, clogging of the filter 9 and the like are prevented, and the solid components are efficiently collected.

The collection tank 7 and the filter 9 are provided with a shielding container 8,
Because it is housed in 10, the radiation radiated from the collected solid components is shielded, and the radiation dose to workers is further reduced. When the collected solid component increases and reaches the radiation dose allowable dose, the alarm of the radiation measuring instruments 27 and 28 attached outside the shielding containers 8 and 10 sounds.

In this state, the shielding containers 8 and 10 are covered, the collection tank 7 and the filter 9 are sealed and accommodated, and the entire shielding containers 8 and 10 are transported to a solid radioactive waste treatment facility (not shown).
This collection tank 7 and filter 9 are treated as solid radioactive waste.

The present invention is not limited to the above embodiment. For example, the collection tank 7 does not necessarily have to have the configuration of the above embodiment. That is, it is only necessary to include the cyclone separator 26 and the filter 9. Further, the high pressure water jetted from the jet nozzle 21 may be configured to use the pool water 2 in the water storage structure 1.

Next, the mechanism of the inspection mechanism 15 is shown in FIG.
This will be described with reference to (a) and (b). As described above, the inspection mechanism unit 15 and the decontamination mechanism unit 16 are attached to the housing 14 and are integrated, and the lower surface is in an open state,
The bottom surface of the water storage structure 1 is sealed with a rubber packing 17. The inspection mechanism 15 and the decontamination mechanism 16 have ears
The hanging ear 18 has a hanging wire 19 attached to it.
Through the lifting hook 20 of the overhead crane
Can be hung. By moving the overhead crane, the inspection mechanism 15 and the decontamination mechanism 16 can be moved to arbitrary locations.

Here, the inspection mechanism 31 of the inspection mechanism section 15 will be described. The inspection mechanism 31 has two ball screws (Y direction) 32 attached thereto. The driving force of a motor (Y direction) 33 causes the Y direction moving mechanism 34 to move the ball screw (Y direction).
It is configured to be movable along 32.

The Y-direction moving mechanism 34 is provided with two ball screws (X direction) 35, and the motor (X
The X-direction moving mechanism 37 can move along the ball screw (X-direction) 35 by the driving force in the direction 36). At the center of the X-direction moving mechanism 37, a probe or a television camera mounting portion 38 is provided. Reference numeral 39 denotes a motor cable, and reference numeral 40 denotes a probe or TV camera cable.

The probe or the TV camera mounting part 38 has an EC.
By installing the T or UT probe or the television camera, the ECT or UT probe or the television camera can be moved in the X and Y directions with the inspection mechanism 15 fixed.

With these configurations, the motor (Y direction) 33 and the motor (X direction) 36 are driven and controlled by remote control from the control device 5 so that the probe of the ECT or UT or the television camera can be moved in the X or Y direction. It has a structure that can move in a direction at a constant speed and a constant distance (pitch).

From the above configuration, the flaw detection images of the ECT and UT and the images of the television camera are provided on the monitor 4 of the ultrasonic flaw detection (UT) and the eddy current flaw detection (ECT) installed on the operation floor 3.
And the shape, size, and depth of the defective portion (including the internal defect) can be specified.

The present invention is not limited to the above embodiment. For example, in a case where the present invention is applied to a wall surface instead of a floor surface, the amount of water jetted from the injection nozzle 21 into the decontamination mechanism unit 16 is made smaller than the amount of water sucked out from the suction nozzle 24, so that the decontamination mechanism unit It is also possible to adopt a configuration in which the interior of 16 becomes a negative pressure and sticks to the wall surface.

Alternatively, suction pads are attached to the corners (four places) where the inspection mechanism 15 and the decontamination mechanism 16 are in contact with the wall surface, and the water in the suction pads is sucked by a suction pump. Thus, the suction pad may be fixed to the wall surface by suction.

According to the present embodiment, in the water storage structure 1 such as an open tank, a pool, or a pit of a nuclear power plant,
An injection nozzle 21 for injecting water toward these inner surfaces, a decontamination mechanism 16 including a high-pressure pump 12 for supplying high-pressure water, a high-pressure water supply tank 13, and a high-pressure hose 22, and the inner surface and floor surface of the water storage structure 1 By providing the inspection mechanism 15 for inspecting the water, the decontamination and the inspection can be simultaneously performed without discharging the pool water 2, and the exposure dose to the decontamination and inspection workers can be greatly reduced.

Conventionally, water was turbid due to the cladding and inspection with a television camera or the like was difficult. However, the cyclone separator 26 for collecting solid components, the collection tank 7 and the downstream side of the cyclone separator 26 are provided. Since the filter 9 and the drain hose 30 are provided, the inspection can be performed without any cladding or dust, and the accuracy of the inspection is greatly improved. In addition, it is possible to collect refuse (solids such as a line and bolts and nuts).

Conventionally, since only inspection with a television camera is possible, it has not been possible to determine whether or not a defect causes leakage or to find an extremely small defect. On the other hand, the inspection mechanism of this embodiment is equipped with a two-dimensional general-purpose camera, ultrasonic inspection (UT), and eddy current inspection (ECT). An extremely small defect can be found, and the shape, size, and depth of the defective portion (including the internal defect) can be specified.

The inspection mechanism 15 has a moving mechanism capable of moving the ultrasonic flaw detection (UT) and eddy current flaw detection (ECT) probes in the X and Y directions. And the inspection work can be performed easily and in a short time.

[0043]

According to the present invention, decontamination and inspection can be performed without discharging water in a water storage structure such as an open tank, a pool, or a pit of a nuclear power plant. Exposure dose can be greatly reduced, and inspection can be performed without cladding or dust, and the accuracy of inspection can be greatly improved.

In addition, it is possible to collect dust (solids such as wire lines, bolts, nuts, etc.), to determine whether or not a defect causes leakage, to find a very small defect, and to detect a defective portion (including an internal defect). The shape, size, and depth of can be specified. Furthermore, the size of a defect or the like can be measured by remote automatic operation, and the inspection operation can be easily performed in a short time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an underwater inspection device such as an open tank of a nuclear power plant according to the present invention.

FIG. 2 (a) is an enlarged view of an inspection mechanism in FIG. 1,
(B) is a bottom view of (a).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water storage structure, 2 ... Pool water, 3 ... Operation floor, 4 ... Monitor of ultrasonic flaw detector (UT), eddy current flaw detector (ETC), 5 ... Control device, 6 ... TV monitor, 7 ... Collection tank , 8 ... Collection tank shielding container, 9 ... Filter, 10 ... Filter shielding container, 11 ... Suction pump, 12 ... High pressure pump, 13 ... High pressure water tank, 14 ... Housing, 15 ... Inspection mechanism part, 16 ... Decontamination Mechanism part, 17 ... rubber packing, 18 ... hanging ear, 19 ... hanging wire,
20 ... hanging hook, 21 ... injection nozzle, 22 ... high pressure hose, 23
... stored water, 24 ... suction nozzle, 25 ... suction hose, 26 ... cyclone separator, 27, 28 ... radiation measuring instrument, 29 ... return line, 30 ... drainage hose, 31 ... inspection mechanism, 32 ... ball screw (Y direction) , 33: Motor (Y direction), 34: Y direction moving mechanism, 35: Ball screw (X direction), 36: Motor (X direction), 37: X direction moving mechanism, 38: Probe or TV camera mounting part , 39: Motor cable, 40: Probe or TV camera cable.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G21F 9/06 521 G21C 17/00 F 541 19/06 A 9/28 522 19/30 A G21D 1/00 T (72 ) Inventor Takayuki Hamashima 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Toshiba Yokohama office (reference) 2G002 AA01 EA12 2G075 AA03 BA17 CA10 CA12 DA16 EA03 FA13 FA16 FC14 GA09 GA37

Claims (4)

[Claims] An injection nozzle that is installed in water in a water storage structure and injects high-pressure water toward an inner surface or a floor surface of the water storage structure, and a high-pressure water supply system that supplies high-pressure water to the injection nozzle. A movable decontamination mechanism part, and a movable inspection mechanism part for detecting a defect on the inner surface or floor surface of the water storage structure. Inspection device. 2. The decontamination mechanism and the inspection mechanism are integrated into a housing by being integrated into a housing. A suction nozzle is attached to the decontamination mechanism, and a cyclone separator and a filter are provided downstream of the suction nozzle. 2. A return line connected to a drainage hose in the water storage structure is provided downstream of the filter.
The underwater inspection device in a storage structure of a nuclear power plant as described in the above. 3. The inspection mechanism includes a two-dimensional general-purpose camera,
The underwater inspection device in a water storage structure of a nuclear power plant according to claim 1, wherein a probe of a three-dimensional camera, an ultrasonic flaw detector or an eddy current flaw detector is attached. 4. The inspection mechanism includes an X, Y probe.
The underwater inspection device in a storage structure of a nuclear power plant according to claim 3, further comprising a moving mechanism that is movable in a direction.