JPH11304985A - Jet pump maintenance device - Google Patents

Abstract

[PROBLEMS] To insert laser surface solution heat treatment means or polishing finishing means together with a TV camera etc. into a riser pipe of a jet pump installed in a reactor pressure vessel without draining reactor water Provide a jet pump maintenance device for inspection and repair. A jet pump maintenance device according to the first aspect of the present invention includes a weld detector for detecting a weld in a piping section of a jet pump and a thermal sleeve installed in a reactor pressure vessel. 30 and the weld 28
Surface solution heat treatment means to irradiate the laser to the surface
And a support means 32 for supporting the welded part detector 28 and the laser surface solution heat treatment means 31 and the like so as to be axially movable at arbitrary positions in the jet pump 9 and the piping such as the thermal sleeve 22. It is characterized by the following.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to maintenance of a jet pump provided in a reactor pressure vessel of a boiling water reactor, and more particularly to a jet pump maintenance device for performing preventive repair of a welded portion in a riser pipe. .

[0002]

2. Description of the Related Art In a boiling water reactor, a jet pump provided in a reactor pressure vessel has a coolant 2 in a reactor pressure vessel 1 as shown in a vertical sectional view of FIG.
And the core 3 are accommodated. The core 3 includes a plurality of fuel assemblies (not shown), control rods, and the like, and is housed in a core shroud 4.

In a reactor pressure vessel 1, a coolant 2 is
Flows upward, and at this time, the temperature is raised and pressurized by the nuclear reaction heat of the reactor core 3, and a two-phase flow state of water and steam is formed. The two-phase flow coolant 2 flows into the steam separator 5 installed above the core 3 and is separated into water and steam.

[0004] Among them, the steam is introduced into a steam dryer 6 installed above the steam separator 5, dried to become dry steam, and passed through a main steam pipe 7 connected to the reactor pressure vessel 1. Are transferred to a steam turbine (not shown) for power generation. On the other hand, the separated water flows down below the reactor core 3 via the downcomer section 8 between the reactor core 3 and the reactor pressure vessel 1. Also, the core shroud 4 is
A plurality of jet pumps 9 are installed at equal intervals around the outer periphery of the furnace. A control rod guide tube 10 is installed below the core 3 and a control rod drive mechanism is provided below the control rod guide tube 10. The control rod driving mechanism 11 controls insertion and withdrawal of a control rod (not shown) into and from the reactor core 3 through the control rod guide tube 10.

A reactor recirculation pump (not shown) is provided outside the reactor pressure vessel 1. The reactor recirculation pump, the jet pump 9, and a reactor recirculation pump (not shown) for connecting between the two. Recirculation pipes constitute the reactor recirculation system. That is, the jet pump 9 forcibly circulates the coolant 2 into the reactor core 3 by the driving water supplied to the jet pump 9 by the reactor recirculation pump.

The jet pump 9 has a riser pipe 12 at the center as shown in a perspective view of a main part of FIG. 14 and a partially cutaway front view of FIG. Coolant 2 supplied from the reactor recirculation pump to
It is introduced via a recirculation inlet nozzle 13. The riser tube 12
A pair of right and left elbows 15a, 15b is connected to the upper part of the elbow via a transition piece 14, and these elbows 15a, 15b are connected to each other.
To each of 15b, via mixing nozzles 16a, 16b,
Inlet throats 17a and 17b are connected.

[0007] Diffusers 18a and 18b are connected to the lower portions of these inlet throats 17a and 17b, respectively. When the coolant 2 is injected from the upper mixing nozzles 16a and 16b, the reactor water is drawn in from the surroundings. Has become.
The injected coolant 2 and the entrained reactor water are mixed in the inlet throats 17a and 17b, and then the hydrostatic head is recovered by the diffusers 18a and 18b.

In the jet pump 9, the flow of the coolant 2 sent from the reactor recirculation pump causes
Since fluid vibration occurs, the riser tube 12 is welded at its lower end to the recirculation inlet nozzle 13 to cope with this,
The upper end is fixed to the reactor pressure vessel 1 via a riser brace 19.

The inflow water pressure of the driving water supplied through the riser pipe 12 acts on the elbows 15a and 15b at the upper end of the jet pump 9. This inflow pressure is elbow 15
a, 15b and inlet throats 17a, 17b and diffusers 18a, 18
Since the driving water is ejected toward the inside b, the reaction force such as the ejection water pressure of the driving water acts upward.

The inlet throats 17a and 17b are mechanically connected to the transition piece 14 via mixing nozzles 16a and 16b and vents 15a and 15b, and the lower ends are inserted into upper ends of diffusers 18a and 18b. ing. Further, lower ends of the diffusers 18a and 18b are fixed to a shroud support 20 welded to the reactor pressure vessel 1, and as shown in a perspective view of a main part of FIG. 16 and a cross-sectional view of a main part of FIG. The lower end of the riser tube 12 is a riser elbow 21
Welded to.

The riser elbow 21 is welded to a thermal sleeve 22, and the thermal sleeve 22 is connected to a recirculation inlet nozzle 13 fixed to the reactor pressure vessel 1. The inlet throats 17a and 17b are mounted on a riser blanket 23 fixed to the riser tube 12. This prevents the riser tube 12 and the inlet throats 17a, 17b from vibrating.

The riser brace 19 is provided with a pad 24 on the inner wall of the reactor pressure vessel 1 as shown in detail in FIG.
Are formed, and four thin plates 25 are welded to the pad 24. The four thin plates 25 have a thickness of about 10 mm. Block at the end of these four thin plates 25
26, the riser tube 12
Are welded inside the block 26. Therefore, the riser brace 19 suppresses the fluid vibration generated in the riser pipe 12 during the operation of the reactor.

The riser brace 19 absorbs the difference in thermal expansion between the reactor pressure vessel 1 made of carbon steel and the riser pipe 12 made of austenitic stainless steel. Therefore, during the operation of the reactor, the reactor is in a deformed state as a state in which the difference in thermal expansion is absorbed. Thus, the jet pump 9
In order to pressurize and circulate the coolant 2 in the reactor core 3, the coolant 2 is used under severe conditions compared to other in-furnace equipments, so that a large load acts on each member, particularly A large stress acts on the riser brace 20 that supports the riser tube 12 in the middle.

[0014]

An excessive load acts on the jet pump 9 due to, for example, breakage of an external pipe such as a reactor recirculation pipe, or
If rust is generated on the inner surface of the riser tube 12 for some reason, the rust may develop into a crack or the like. In addition, since austenitic stainless steel pipe is mainly used as the material of the riser pipe 12, if the three conditions of stress, corrosion environment, and material (generation of a chromium deficiency layer) are satisfied, stress corrosion cracking (Stress Crrosion Cracking)
It is assumed that the riser tube 12 is damaged.

Since this stress corrosion cracking phenomenon does not occur if at least one of the three conditions is missing, various measures must be taken to prevent the stress corrosion cracking. Further, if rust or cracks are generated on the surface of the jet pump 9 due to some cause, if these are left untreated, the cracks may progress and the jet pump 9 may be cracked.

Therefore, it is not preferable that the jet pump 9 for controlling the output of the nuclear reactor be in such a state, because it may adversely affect other structures.

An object of the present invention is to provide a T pump inside a riser pipe of a jet pump installed in a reactor pressure vessel.
An object of the present invention is to provide a jet pump maintenance device for performing inspection and repair without removing reactor water by inserting a laser surface solution heat treatment device or an inner surface polishing device together with a V camera or the like.

[0018]

According to a first aspect of the present invention, there is provided a jet pump maintenance device according to the present invention.
A weld detector for detecting a weld or the like in a jet pump and a pipe section installed in a reactor pressure vessel, and a surface solution heat treatment means for irradiating a laser to the weld and the like,
Support means for supporting the weld detector and the laser surface solution heat treatment means at any position in the jet pump and the pipe so as to be able to move in the axial direction.

Inside the jet pump and the pipe section, etc., a weld section is detected by a weld section detector.
After being supported at a predetermined position by a support means, the welded portion and the like are subjected to laser irradiation from the laser surface solution heat treatment means to perform a surface solution heat treatment.

According to a second aspect of the present invention, there is provided a jet pump maintenance device according to the first aspect, wherein the laser surface solution heat treatment means is provided with at least one refraction portion in the laser transmission path so as to be refractible and has a tip. The laser irradiation portion provided is movable in the circumferential direction at an arbitrary angle with respect to the welding portion or the like, and is subjected to surface solution heat treatment by laser irradiation.

In the jet pump maintenance device, since the laser transmission path is made freely refractable by the refraction part, the laser irradiation part is refracted and stored when inserted into a jet pump or the like. In addition, the laser irradiation section can be bent or extended or rotated to appropriately face the inner surface of the pipe section or the like.

According to a third aspect of the present invention, in the jet pump maintenance apparatus according to the second aspect, the laser irradiation unit surrounds the surface solution heat treatment target in water and surrounds the laser irradiation position with a gas supplied from the outside. And a seal cover for isolating from water.

At the time of surface solution heat treatment by laser irradiation, a space between the laser irradiation part and the surface solution heat treatment part is surrounded by a seal cover and the inside is filled with an atmosphere gas.
Separate from surrounding furnace water. Thereby, the surface solution heat treatment by laser irradiation can be favorably performed without draining the reactor water in the reactor pressure vessel.

According to a fourth aspect of the present invention, there is provided the jet pump maintenance apparatus according to the first aspect, wherein the laser surface solution heat treatment means is provided with a TV camera for inspection and monitoring near the laser irradiation part or the laser irradiation part. It is characterized by. The underwater TV camera can be used to check the internal state, detect the position of the surface solution heat treatment unit, monitor the surface solution heat treatment, and confirm the surface solution heat treatment result.

According to a fifth aspect of the present invention, there is provided a jet pump maintenance apparatus according to the first aspect, wherein the laser irradiation section is disposed at a rear portion of the supporting means and the laser surface solution heat treatment means.

Since the laser irradiation section is disposed behind the supporting means and the laser surface solution heat treatment means, the jet pump maintenance device is once passed through the surface solution heat treatment section and then retracted to perform positioning and laser irradiation work. I do. Thereby, the surface solution heat treatment in the jet pump and the pipe portion can be performed in a circumferentially substantially parallel manner.

According to a sixth aspect of the invention, there is provided a jet pump maintenance device according to the first aspect, wherein the laser irradiating section is disposed at an end extending in the axial direction behind the supporting means and the laser surface solution heat treatment means. Features. By reducing the outer diameter of the jet pump maintenance device and separating the laser irradiation part from the laser surface solution heat treatment means,
In particular, the surface solution heat treatment by laser irradiation can be easily performed even on the welded portion between the transition piece and the riser pipe having a narrow entrance.

A seventh aspect of the present invention is directed to a jet pump maintenance apparatus according to the first aspect, wherein the laser irradiation section is disposed in front of the support means and the laser surface solution heat treatment means. Since the laser irradiation unit is arranged in front of the support means and the laser surface solution heat treatment means,
By inserting the jet pump maintenance device before the surface solution heat treatment, inspection and laser irradiation work can be performed on the welds between the riser pipe and the riser vent and between the thermal sleeve and the recirculation inlet nozzle.

[0029] A jet pump maintenance device according to an eighth aspect of the present invention provides a jet pump maintenance device for detecting a weld portion or the like in a jet pump and a pipe portion installed in a reactor pressure vessel, and polishing the weld portion and the like. Polishing finishing means,
Support means for supporting the weld detector, the polishing finish means, and the like so as to be able to move in the axial direction at arbitrary positions in the jet pump and the piping.

In the inside of the jet pump and the pipe section, etc., a weld section is detected by a weld section detector.
The welded portion and the like are polished by a polishing finish means while being supported at a predetermined position by a support means.

According to a ninth aspect of the present invention, in the jet pump maintenance device according to the ninth aspect, the polishing and finishing means is capable of moving the rotating grindstone in the axial direction and the circumferential direction by bringing the rotating grindstone into contact with the welding portion or the like. It is characterized by. Polishing for a welded portion or the like is performed in a wide range by rotating a grinding wheel and moving it in the axial and circumferential directions.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. Note that the same components as those of the above-described conventional technology are denoted by the same reference numerals, and detailed description is omitted. The first embodiment is suitable for a welded portion between a transition piece and a riser pipe or the like according to claims 1 to 5, and as shown in a vertical sectional view of FIG. Is inserted from the transition piece 14 at the upper part of the jet pump 9,
12, the riser elbow 21, and the thermal sleeve 22 are installed at the center of the shaft (FIG. 1 shows the installation inside the thermal sleeve 22).

The jet pump maintenance device 27 includes, for example, a weld 28 between the riser elbow 21 and the thermal sleeve 22.
And a weld detector 30 for detecting a weld 29 between the riser pipe 12 and the riser elbow 21 and a laser for irradiating the welds 28 and 29 with a laser to improve the quality of the inner surface of the pipe by solution heat treatment. A surface solution heat treatment means 31 is provided. Also,
The weld detector 30 and laser surface solution heat treatment means
A support means 32 for supporting the shaft 31 arbitrarily in the axial direction with the shaft 31 as the center of the shaft in the pipe (claim 1).

The jet pump maintenance device 27 includes a power source and a control signal cable and a laser for power of a power source corresponding to an operation operation by an operator from a fuel exchanger (not shown) or the like above the reactor pressure vessel 1. A power transmission tube 33 composed of an optical fiber cable for transmitting light, an atmosphere gas filled in the surface solution heat treatment part, and a pipe for suctioning and collecting compressed air and bubbles generated during the surface solution heat treatment is connected.

The laser surface solution treatment means 31 includes a power transmission tube.
From a supply port 34 that receives the laser light supplied via 33,
As for the laser transmission path between the laser irradiation units 35, at least one refraction unit including a mirror 37 and the like is provided in addition to the condenser lens 36. This allows the laser transmission path to be bent freely so that the laser irradiating section 35 can be stored in the laser surface solution treatment means 31, and the laser beam is reflected or refracted by the mirror 37 or the like, and the laser beam is reflected. The transmission is performed without any trouble to the laser irradiation unit 35 provided at the end of the transmission path.

Therefore, the laser irradiating section 35 is made to face the welding section 28 at an arbitrary angle by the tilt motor 38, and further, the laser irradiating section 35 is rotated along the inner circumference of the pipe by the turning motor 39. The laser beam is
(Claim 2).

A seal cover 40 is provided at the tip of the laser irradiating section 35. The seal cover 40 surrounds the surface solution heat treatment section on the inner periphery of the pipe section in water, and the power transmission pipe 33. Atmospheric gas supplied via the irradiator removes water from the surface solution heat treatment part in the seal cover 40 at the tip of the laser irradiation part 35, fills the inside with the atmosphere gas, and isolates it from the outside in a watertight manner. (Claim 3).

The laser surface solution heat treatment means 31 checks the processing results in the surface solution heat treatment part along or near the laser irradiation part 35, and checks the inner circumference of each pipe and the welding. For example, an underwater TV camera 41 for performing inspection and monitoring of the unit 28 and a lighting device 42 for facilitating observation are provided (claim 4). Further, the laser surface solution heat treatment means 31 is configured by arranging a laser irradiating section 35 behind and behind the support means 32 (claim 5).

Further, as shown in a longitudinal sectional view along the line AA in FIG. 1 of FIG. 2, the support means 32 is located in the axial direction of the laser surface solution heat treatment means 31 and has a roller at its tip. Three support arms 44 provided with 43 are provided so as to be freely expandable and contractible in the radial direction by respective support cylinders 45.

Therefore, by extending the three support arms 44 by the same amount, the laser surface solution heat treatment means 31 together with the support means 32 can be supported on the center of the shaft inside the thermal sleeve 22 or the like which is the piping portion. . In FIG. 1, the storage state where the support arm 44 is contracted above the axis center is shown, and the support state where the support arm 44 is extended is shown below the axis center.

Next, the operation of the above configuration will be described. The jet pump maintenance device 27 stores the laser irradiation part 35 of the laser surface solution heat treatment means 31 in a folded state, and shrinks the support arm 44 of the support means 32 so that there is no protruding portion around the circumference. Connecting.

An operator operates the jet pump maintenance device 27 from a refueling machine or the like (not shown) at the upper part of the reactor pressure vessel 1 and suspends the support means 32 with a wire rope of an auxiliary hoist (not shown) with the support means 32 at a lower position. It is inserted from the transition piece 14 above the jet pump 9.

The jet pump maintenance device 27 is guided by the riser elbow 21 through the riser pipe 12 of the jet pump 9 and inserted into the horizontal thermal sleeve 22. And the support cylinder 45 of the support means 32 is extended evenly by the compressed air or hydraulic pressure supplied from the power transmission tube 33 to the three support arms 44.

As a result, the rollers 43 at the tips of the three support arms 44 come into contact with the inner surface of the thermal sleeve 22, and the jet pump maintenance device 27 is installed at the center of the shaft. Along with the laser irradiator 35, the weld detector 30, the underwater TV camera 41, and the illuminator 42 are at right angles to the axis center so as to face the inner surface of the thermal sleeve 22.

When the illuminator 42 is turned on, an image of the inner surface of the thermal sleeve 22 by the underwater TV camera 41 is clearly transmitted to the worker via the power transmission tube 33 on a monitor (not shown). Accordingly, the jet pump maintenance device 27 once inserted into the thermal sleeve 22 is pulled toward the riser elbow 21 by the rolling of the roller 43 of the support means 32 by pulling the wire rope, and is moved. The condition of the inner surface of the riser elbow 22 and the riser elbow 21 can be inspected sequentially and in detail.

If the weld detector 30 is, for example, of the magnetic detection type, the material of the riser pipe 12 and the riser elbow 21 of the pipe section, the thermal sleeve 22, and the welds 28 and 29 connecting the two are connected. However, since the carbon steel, stainless steel, and the like are different from each other, the weld detector 30 detects the difference between the respective magnetic properties, and detects the change point as the welds 28 and 29.

For the inspection of the inner circumference of the thermal sleeve 22, the turning motor 39 is driven to rotate the laser irradiation section 35 along the inner circumference of the pipe, so that the weld detector 30 is checked.
And the underwater TV camera 41 also rotate. Therefore, by this rotation and the pulling operation of the wire rope, the underwater TV camera 41 and the weld detector 30 can easily inspect the entire inner surface of the thermal sleeve 22 and confirm the position of the weld 28.

The inner surface of the thermal sleeve 22 and the welded portion
If it is determined from the result of inspection of 28 that surface solution heat treatment is necessary for a part or the entire circumference of the welded part 28,
The position of the welded part 28 is confirmed by the welded part detector 30 and the laser irradiation part 35 of the laser surface solution heat treatment means 31 is positioned, so that a predetermined surface solution heat treatment part is covered with a seal cover 40.

Thereafter, an atmosphere gas is filled into the seal cover 40 via the power transmission tube 33, the reactor water is removed from the surface solution heat treatment unit, and then the laser irradiation unit 35 irradiates the surface with laser. A solution heat treatment is performed. Also at this time, the surface solution heat treatment of the laser irradiation unit 35 can be performed on a part or the entire circumference of the welding part 28 by driving the tilt motor 38 and the turning motor 39 and pulling the wire rope.

At this time, in order to set and maintain the laser irradiation position, the laser irradiation section 35 bends the laser transmission path so that it can be freely bent.
The laser beam is refracted by the mirror 37 and the like. Thereby, the laser light transmitted via the power transmission tube 33 is condensed by the installed condenser lens 36 in the laser transmission path from the supply port 34, and is appropriately refracted by the mirror 37 and the like. The laser irradiation part 35 irradiates the surface solution heat treatment part on the inner surface of the thermal sleeve 22.

Therefore, even when the laser transmission path is bent as appropriate during the insertion of the jet pump maintenance device 27 and during the laser surface solution heat treatment, the laser light is reflected or refracted by the mirror 37 or the like, and is applied to the tip of the laser transmission path. It is transmitted to the provided laser irradiation unit 35 without any trouble. Further, the finished state of the laser surface solution treatment can be confirmed in detail by the underwater TV camera 41.

By performing the laser surface solution treatment by the jet pump maintenance device 27, the jet pump 9
To prevent stress corrosion cracking at the welded portion 28 connecting the riser elbow 21 and the thermal sleeve 22 at the same time, and to prevent rust and cracks from being generated on the inner surface of the jet pump 9 and the piping by any cause, and to prevent the expansion and damage caused by the rust and cracks. Can be prevented.

The second embodiment is suitable for a welded portion between the transition piece 14 and the riser tube 12 according to claim 6, and is a modification of the first embodiment. Are almost the same as in the first embodiment, and therefore, only the differences will be described. A longitudinal sectional view of FIG. 3 and a plan view of FIG. 4,
As shown in FIG. 5 and a cross-sectional view along the line BB in FIG. 3, the jet pump maintenance device 46 includes a laser irradiation unit 35 of the laser surface solution heat treatment unit 47 and a support unit.
It protrudes from the rear of 32.

That is, the laser surface solution heat treatment means 47
At the rear of the support means 32, a supply port to which a power transmission tube 33 is connected
At the tip of the extension joint 48 attached in parallel with 34, the laser irradiation unit 35 is arranged together with the weld detector 30, etc., and the laser transmission path from the supply port 34 to the laser irradiation unit 35 is configured to be refractible. . Thus, the outer diameter of the jet pump maintenance device 46 is made smaller than that of the first embodiment, and the jet pump maintenance device 46 is shaped so that it can easily pass through a narrow place.

Next, the operation of the above configuration will be described. In the laser surface solution heat treatment means 47, the jet pump maintenance device 46 in which the laser irradiation section 35 is in parallel with the supply port 34 is hung by a wire rope (not shown). Can be easily inserted into the riser tube 12 from the narrow opening hole of the transition piece 14 in FIG.

When the jet pump maintenance device 46 reaches the riser pipe 12, the laser irradiation unit 35 is moved together with the weld detector 30 and the like with the center of the axis so as to face the inner surface of the riser pipe 12 by the tilt motor 38 (not shown). Make a right angle position. In this state, the welding part detector 30 and the underwater TV camera 41 (not shown) are driven by the pulling of the wire rope and the driving of the turning motor 39.
Is used to detect the inspection position of the weld 49 or the like connecting the transition piece 14 and the riser pipe 12.

The jet pump maintenance device 46 operates the support means 32 at the weld 49 or the like confirmed by the weld detector 30 or the like to position the weld pump 49 at the axial center of the riser pipe 12.
Inspect 49 and its surroundings with the underwater TV camera 41 in detail. As a result of this inspection, if laser irradiation surface solution treatment is required, laser irradiation surface solution treatment is performed on a predetermined portion by laser light irradiated from the laser irradiation unit 35.

When the position detection and inspection of the inspection section and the surface solution heat treatment are performed, the laser irradiating section 35 and the welded section detector 30 are disposed behind the laser surface solution heat treatment means 47 at the end of the extension joint 48. The inspection and the surface solution heat treatment can be easily performed on the welded portion 49 between the transition piece 14 and the riser tube 12 and a narrow place around the transition piece 14.

The third embodiment is suitable for a welding portion between the thermal sleeve 22 and the recirculation inlet nozzle 13 and a welding portion 29 between the riser pipe 12 and the riser elbow 21. Since this is a modification of the first embodiment, the main components are almost the same as those of the first embodiment, and therefore, only the differences will be described.

As shown in the longitudinal sectional view of FIG. 6, the partially cutaway plan view of FIG. 7, and the transverse sectional view of FIG. 8, in the jet pump maintenance device 50, the laser surface solution heat treatment means 51 is provided. The laser irradiating section 35 is provided in front of the supporting means 32, and the laser irradiating section 35 is provided at the tip of the laser surface solution heat treatment means 51.
The laser transmission path up to is configured to be refractible.

Therefore, as compared with the first and second embodiments, the inspection and the laser surface solution heat treatment can be performed even in a portion where the insertion of the jet pump maintenance device 50 is difficult. .

Next, the operation of the above configuration will be described. As shown in FIGS. 7 and 8, with the laser irradiation section 35 provided at the end of the laser surface solution heat treatment means 51 facing forward, the jet pump maintenance device 50 is suspended by a wire rope (not shown). Is inserted into the thermal sleeve 22 from the riser pipe 12 of the jet pump 9.

When the jet pump maintenance device 50 reaches the inside of the thermal sleeve 22, the laser surface solution heat treatment means 51
As shown in FIG. 6, the laser irradiating section 35 is positioned at a right angle to the center of the axis together with the welding section detector 30 and the like so as to face the inner surface of the thermal sleeve 22 by the tilt motor 38 as shown in FIG. In this state, inspection of the welded portion 52 connecting the thermal sleeve 22 and the recirculation inlet nozzle 13 and the like is performed by using the welded portion detector 30 and the underwater TV camera 41 by pulling the wire rope and driving the turning motor 39. Perform position detection.

The jet pump maintenance device 50 is configured to operate the support means 32 at the welded part 52 and the like confirmed by the welded part detector 30 and the like to position the welded part 52 at the axial center of the thermal sleeve 22 and then to position the welded part located in front of it. The underwater TV camera 41 and 52 and its surroundings are inspected in detail. As a result of this inspection, if laser irradiation surface solution treatment is required, laser irradiation surface solution treatment is performed on a predetermined portion by laser light irradiated from the laser irradiation unit 35.

In performing the position detection and inspection of the inspection section and the surface solution heat treatment, the laser irradiating section 35 and the welded section detector 30 are operated by the laser surface solution heat treatment means 51 at the tip of the laser surface solution heat treatment means 51. The means 51 is arranged in front of the support means 32. Therefore, the jet pump maintenance device 50 can be easily installed on the thermal sleeve 22 without inserting the jet pump maintenance device 50 into the recirculation inlet nozzle 13 at the back with respect to the welded portion 52 located in front of the thermal sleeve 22. Inspection and surface solution heat treatment.

The fourth embodiment is directed to claim 8 or claim 9 in which the inner surfaces of the jet pump 9 and the pipe portion are polished, and the components of the fourth embodiment are the same as those of the first embodiment. The description of the parts is omitted. As shown in the vertical cross-sectional view of FIG. 9 and the vertical cross-section along the line CC in FIG. 9 of FIG. 9, and the partially cut-away plan view of FIG.
The jet pump maintenance device 53 has a polishing and finishing means 54 in front of the support means 32.

The polishing and finishing means 54 is provided with a grindstone 55 for polishing and polishing the surfaces of the jet pump 9 and the piping, and a welding part detector 30, an underwater TV camera 41 and an illuminating tool 42 at its tip. Is configured to be able to be supported at an arbitrary position inside the jet pump 9 and the pipe by the support means 32 (claim 8).

Further, as shown in FIG.
Is rotatably connected to the support means 32 around the axis thereof by driving a turning motor 39, and a grindstone 55 rotated by a grindstone motor 56 is disposed near the tip. Further, the grinding wheel 55 is supported by a grinding cylinder 57 that moves in a radial direction at right angles to the axis center together with a grinding wheel motor 56, and a pantograph arm 58 (claim 9).

In FIG. 9, the state in which the support means 32 and the polishing and finishing means 54 are both housed above the axis is shown.
The lower part shows the state in which the support means 32 supports the thermal sleeve 22 and the polishing and finishing means 54 polishes the inner surface of the thermal sleeve 22.

Next, the operation of the above configuration will be described. As shown in the vertical sectional view of the main part of FIG. 12, the jet pump maintenance devices 27 and 53 are both suspended from the upper part of the reactor pressure vessel 1 by a wire rope 59 from an auxiliary hoist of a fuel exchanger (not shown).

The jet pump maintenance devices 27 and 53 include a reactor shroud 4 surrounding the outer periphery of the reactor pressure vessel 1 and the reactor core 60.
Between the riser pipe 12 of the jet pump 9 and the lower part by rotating the riser elbow 21 and inserting it inside the thermal sleeve 22 to inspect and check the surface in the respective paths. Work such as solution heat treatment and polishing finish is performed.

In the jet pump maintenance device 53, FIG.
In the storage state shown in FIG. 11, as shown in the upper half of FIG.
For example, the jet pump maintenance device 53 is inserted into the thermal sleeve 22, and the jet cylinder maintenance device 53 is supported by the support cylinder 44 of the support means 32 and the roller 43 as shown in the lower half of FIG. 9. In this state, while pulling the wire rope 59 and driving the turning motor 39, the welding section 52 connecting the thermal sleeve 22 and the recirculation inlet nozzle 13 using the underwater TV camera 41 and the welding section detector 30 is used.
For example, a place where polishing is required is detected.

When a place requiring polishing finish is detected, the jet pump maintenance device 53 is moved to extend the polishing cylinder 57 and the pantograph arm 58 to bring the grindstone 55 into contact with a predetermined position. The underwater TV camera 41 confirms the polishing finish position. Thereafter, the grindstone motor 56 is driven to perform the polishing finish by the grindstone 55. In this polishing finishing operation, the inner periphery of a fixed position is performed on the inner surface of the thermal sleeve 22, for example, by driving the turning motor 39.

Further, by pulling the wire rope 59 and moving the jet pump maintenance device 53 in the axial direction, the entire inner surface of the thermal sleeve 22 can be finished. Further, the status monitoring of the finishing work and the checking and checking of the finishing result can be easily performed by the underwater TV camera 41.

The finishing work by the jet pump maintenance device 53 is performed by the jet pump maintenance devices 27 and 46,
Prior to the laser surface solution heat treatment work by 50, besides checking the condition of the jet pump 9 and the pipe portion, and confirming, for example, by polishing a part of the rust generation site, minor repair can be performed.

[0076]

As described above, according to the present invention, the laser surface solution heat treatment means and the polishing and finishing means in the jet pump maintenance device are used to check the soundness of the inside of the jet pump and the piping from the state of the welded parts, etc. Soundness can be easily restored by surface solution heat treatment by laser irradiation and repair work by polishing finish.

Further, since the maintenance work by the inspection and repair is performed by monitoring the underwater TV camera from outside the reactor pressure vessel and by remote control, it is necessary to drain the reactor water in the reactor pressure vessel to a full state. Therefore, the work is simple, the soundness and reliability of the jet pump can be improved, and the radiation exposure of workers can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a jet pump maintenance device according to a first embodiment of the present invention.

FIG. 2 shows A in FIG. 1 of the first embodiment according to the present invention.
FIG. 4 is a vertical cross-sectional view along the line A.

FIG. 3 is a longitudinal sectional view of a jet pump maintenance device according to a second embodiment of the present invention.

FIG. 4 is a plan view of a second embodiment according to the present invention.

FIG. 5 is a view showing a portion B in FIG. 3 of a second embodiment according to the present invention
FIG. 3 is a transverse cross-sectional view along the line B.

FIG. 6 is a longitudinal sectional view of a jet pump maintenance device according to a third embodiment of the present invention.

FIG. 7 is a partially cutaway plan view of a main part of a third embodiment according to the present invention.

FIG. 8 is a cross-sectional view of a third embodiment according to the present invention.

FIG. 9 is a longitudinal sectional view of a jet pump maintenance device according to a fourth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of the fourth embodiment according to the present invention, taken along line CC in FIG. 9;

FIG. 11 is a partially cutaway plan view of a fourth embodiment according to the present invention.

FIG. 12 is a vertical sectional view of a main part showing a handling state of the jet pump maintenance device according to the present invention.

FIG. 13 is a longitudinal sectional view of a boiling water reactor.

FIG. 14 is a perspective view of a jet pump.

FIG. 15 is a partially cutaway front view of the transition piece and the elbow.

FIG. 16 is an essential part perspective view of a riser brace, a riser pipe, and a riser elbow.

FIG. 17 is a cross-sectional view of a riser brace section.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Coolant, 3 ... Reactor water, 4 ... Core shroud, 5 ... Steam separator, 6 ... Steam dryer, 7 ... Main steam pipe, 8 ... Downcomer section, 9 ... Jet pump ,Ten…
Control rod guide tube, 11 ... control rod drive mechanism, 12 ... riser tube, 13
... Recirculation inlet nozzle, 14 ... Transition piece, 15
a, 15b: Elbow, 16a, 16b: Mixing nozzle, 17a, 17
b: Inlet throat, 18a, 18b: Diffuser,
19 ... riser brace, 20 ... shroud support, 21 ... riser elbow, 22 ... thermal sleeve, 23 ... riser blanket, 24 ... pat, 25 ... thin plate, 26 ... block, 27, 4
6, 50, 53 ... jet pump maintenance device, 28, 29, 49, 52
... Welded part, 30 ... Welded part detector, 31, 47, 51 ... Laser surface solution heat treatment means, 32 ... Support means, 33 ... Power transmission tube, 34 ... Supply port, 35 ... Laser irradiation part, 36 ... Condensing lens , 37 ... mirror, 38 ... tilt motor, 39 ... turning motor, 40 ... seal cover, 41 ... underwater TV camera, 42 ... lighting equipment, 43 ... roller, 44
... support arm, 45 ... support cylinder, 48 ... extension joint, 54 ...
Polishing means, 55: grinding wheel, 56: grinding wheel motor, 57: grinding cylinder, 58: pantograph arm, 59: wire rope, 60: core.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F04F 5/44 F04F 5/44 Z

Claims (9)

[Claims] 1. A weld detector for detecting a weld or the like in a jet pump and a pipe installed in a reactor pressure vessel, surface solution heat treatment means for irradiating the weld with a laser, and the welding part. A jet pump maintenance device, comprising: a support unit for supporting a detector, a laser surface solution heat treatment unit, and the like so as to be movable in an axial direction at an arbitrary position in the jet pump and the pipe. 2. The laser surface solution heat treatment means comprises a laser transmission path provided with at least one refraction part to be refractible, and a laser irradiation part provided at the tip being at an arbitrary angle with respect to a welding part or the like. 2. The jet pump maintenance device according to claim 1, wherein the surface solution heat treatment is performed by laser irradiation so as to be movable in a circumferential direction. 3. The laser irradiation unit includes a seal cover that surrounds a surface solution heat treatment target in water and isolates a laser irradiation position from surrounding water by a gas supplied from the outside. Item 2. A jet pump maintenance device according to Item 2. 4. The jet pump maintenance apparatus according to claim 1, wherein said laser surface solution heat treatment means is provided with a TV camera for inspection and monitoring near said laser irradiation section or said laser irradiation section. 5. The jet pump maintenance device according to claim 1, wherein the laser irradiation unit is disposed at a rear portion of the support unit and the laser surface solution heat treatment unit. 6. The jet pump maintenance device according to claim 1, wherein the laser irradiation unit is disposed at an end extending in the axial direction behind the support means and the laser surface solution heat treatment means. 7. The jet pump maintenance device according to claim 1, wherein the laser irradiation unit is disposed in front of a support unit and a laser surface solution heat treatment unit. 8. A weld detector for detecting a weld or the like in a jet pump and a piping section installed in a reactor pressure vessel, polishing and finishing means for polishing the weld and the like, the weld detector and A support means for supporting the polishing and finishing means and the like so as to be movable in the axial direction at an arbitrary position in the jet pump and the pipe. 9. The jet pump maintenance device according to claim 8, wherein the polishing and finishing means is capable of moving a rotating grindstone in the axial direction and the circumferential direction by making contact with the welding portion or the like.