Water jet peening device

The water jet peening device of the present invention is provided with: a swiveling mechanism for swiveling a spray nozzle in the horizontal direction centered on a positioning member that is positioned at the upper end of an instrumentation tube support; a lift mechanism for raising and lowering the spray nozzle in the vertical direction with respect to the positioning member that is positioned at the upper end of the instrumentation tube support; and a rotation mechanism for supporting the spray nozzle so as to be able to rotate centered on a downward-inclined rotation shaft center on the positioning member end of the vertical direction, disposing a spray port aimed toward the side of the rotation shaft center in a direction that is at a slant from the rotation shaft center, and rotating the spray nozzle centered on the rotation shaft center.

TECHNICAL FIELD

The present invention relates to a water jet peening device that repairs a tube support provided in a reactor vessel and the periphery of the tube support.

BACKGROUND ART

For example, in a nuclear power plant including a Pressurized Water Reactor (PWR), light water is used as a nuclear reactor coolant and a neutron moderator and becomes high-temperature and high-pressure water that do not boil surrounding the entire reactor core, the high-temperature and high-pressure water is fed to a steam generator, steam is generated by heat exchange, and the steam is fed to a turbine generator to generate electricity.

In the nuclear power plant, it is necessary to examine various structures or the like of the pressurized water reactor at fixed intervals in order to secure sufficient safety and reliability. In addition, when the examination is performed and defects are found, necessary locations related to the defects are repaired. For example, in the pressurized water reactor, a plurality of instrumentation tube supports penetrating a lower head are provided in a reactor vessel main body, and in each instrumentation tube support, a conduit tube is connected to the lower end portion outside the reactor while an in-core instrumentation guide tube is fixed to the upper end portion inside the reactor. In addition, a neutron flux detector capable of measuring a neutron flux is inserted from the instrumentation tube support into a reactor core (fuel assembly) through the in-core instrumentation guide tube by the conduit tube.

An in-core instrumentation tube is fitted so as to be welded to a mounting hole of the reactor vessel main body, and thus, the instrumentation tube support is configured. Accordingly, tensile stress may remain on the in-core instrumentation tube, or the welded section of the in-core instrumentation tube and the periphery of the welded section, and thus, probability of occurrence of stress corrosion cracking due to long-time use becomes higher. Therefore, in the related art, there is a technology of water jet peening that prevents the stress corrosion cracking by improving tensile residual stress of a surface so as to be compression residual stress. In the water jet peening, high-pressure water including cavitation bubbles is sprayed on the surface of a metal member in water, and the tensile residual stress on the surface of the metal member is improved so as to be the compression residual stress. For example, this water jet peening device is disclosed in PTL 1 below.

In the water jet peening device disclosed in PTL 1, a spray nozzle is configured to swivel centered on an instrumentation tube support, to be raised and lowered in a vertical direction (up-down direction) of the instrumentation tube support, to swing in the downward direction or a direction inclined with respect to the instrumentation tube support, and to move in a front-rear direction in which the spray nozzle approaches or moves away from the instrumentation tube support. Accordingly, the water jet peening is performed on the outer circumferential surface of the instrumentation tube support, and the welded section of the instrumentation tube support with respect to the reactor vessel.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Since the water jet peening device described in PTL 1 is configured so that the spray nozzle swings in the downward direction or in the direction inclined with respect to the instrumentation tube support, the water jet peening is performed on the outer circumferential surface of the instrumentation tube support and the welded section of the instrumentation tube support with respect to the reactor vessel main body. When the spray nozzle is swung, the position of the jetting port of the spray nozzle is displaced from the center of the instrumentation tube support in the radial direction, the distance between the metal member surface and the jetting port of the spray nozzle is changed, and thus, there is a concern that effects of the water jet peening may be decreased or may not be obtained. Accordingly, in the water jet peening device disclosed in PTL 1, in order to solve this problem, the spray nozzle is configured to move in the front-rear direction.

However, if the number of the movement mechanisms of the spray nozzle is increased, the size of the device is increased. Since the instrumentation tube support is erected on the bottom portion of the reactor vessel main body, if the size of the device is increased, there are concerns that the device may interfere with other instrumentation tube supports adjacent to the instrumentation tube support subjected to the water jet peening, or the device may interfere with a support frame supporting the in-core structure in the reactor vessel main body in the outermost instrumentation tube support, and thus, the increased device size is not preferable. In addition, if the number of the movement mechanisms of the spray nozzle is increased, the controls of the movement mechanisms are multiplied and become complicated, and there are more factors causing failure.

The present invention is to solve the above-described problems, and an object thereof is to provide a water jet peening device capable of performing water jet peening on the outer surface of an instrumentation tube support and the welded section of the instrumentation tube support while preventing increased device size and complexity.

Solution to Problem

In order to solve the above-described problems, there is provided a water jet peening device in which a spray nozzle is provided along with a positioning member positioned at the upper end of an instrumentation tube support, and a water jet is sprayed from a spray port of the spray nozzle, including: a swiveling mechanism that swivels the spray nozzle in a horizontal direction centered on the positioning member positioned at the upper end of the instrumentation tube support; a lift mechanism that raises and lowers the spray nozzle in a vertical direction with respect to the positioning member positioned at the upper end of the instrumentation tube support; and a rotation mechanism that supports the spray nozzle so as to be able to rotate centered on a downward-inclined rotation shaft center on the positioning member side in the vertical direction, disposes the spray port aimed toward the rotation shaft center side in a direction that is inclined with respect to the rotation shaft center, and rotates the spray nozzle centered on the rotation shaft center.

According to the water jet peening device, in the rotation mechanism, the spray nozzle is supported so as to be able to rotate centered on the downward-inclined rotation shaft center on the positioning member side in the vertical direction, the spray port is disposed aimed toward the rotation shaft center side in the direction that is inclined with respect to the rotation shaft center, and the spray nozzle is rotated centered on the rotation shaft center. Accordingly, a state where the spray port is disposed in the direction inclined at a predetermined angle from the vertical direction at the position at which the distance in the horizontal direction from the positioning member side is relatively long, and a state where the spray port is disposed in the vertical direction at the position at which the distance in the horizontal direction from the positioning member side is relatively short are obtained. Accordingly, it is possible to adjust the position in the horizontal direction by the rotation mechanism. As a result, according to the configurations of the swiveling mechanism, the lift mechanism, and the rotation mechanism, it is possible to perform the water jet peening on the outer surface of the instrumentation tube support and the welded section of the instrumentation tube support while preventing an increased size and complexity of the device.

In addition, in the water jet peening device of the present invention, the rotation mechanism may include: a rotation shaft that supports the spray nozzle so as to be able to rotate with respect to a base portion of the rotation shaft; an introduction path that is provided in the inner portion of the base portion and introduces high-pressure water; a communication path that is provided in the inner portion of the rotation shaft and causes the introduction path and the spray port to communicate with each other; and a sealing material that seals a communication portion between the communication path and the introduction path while allowing the rotation of the rotation shaft.

According to the water jet peening device, it is possible to connect a high-pressure water supply tube that supplies the high-pressure water to the introduction path provided in the base portion which is the fixed side, and it is possible to spray the high-pressure water from the spray port while preventing torsion in the high-pressure water supply tube from being generated when the spray nozzle is rotated and preventing the high-pressure water from being leaked outside the rotation shaft by the seal material.

In addition, in the water jet peening device of the present invention, the rotation mechanism may include: a pinion gear that is provided in the spray nozzle centered on the rotation shaft center; a rack gear that meshes with the pinion gear; and a cylinder that slidingly moves the rack gear.

Since the application of the water jet peening is performed in water, if a motor or the like is used in the rotation mechanism, a mechanism or the like having a waterproof function is required, and thus, the increase in the size of the rotation mechanism occurs. Meanwhile, according to the water jet peening device of the present invention, since the rack gear is slidingly moved by the cylinder and the pinion gear is rotated accompanied by the spray nozzle, the waterproof function is not required, and it is possible to prevent the increase in the size of the rotation mechanism.

In addition, the water jet peening device of the present invention may further include restricting means for restricting the rotation of the spray nozzle at both positions at which the direction of the spray port is reversed according to the rotation of the spray nozzle.

According to the water jet peening device, since the restricting means is provided, in the configuration in which the rack gear is slidingly moved by the cylinder and the pinion gear is rotated accompanied by the spray nozzle, there is restriction at both positions at which the direction of the spray port is reversed, and thus, it is possible to move the spray port toward the appropriate position.

Advantageous Effects of Invention

According to the present invention, it is possible to perform water jet peening on the outer surface of an instrumentation tube support and the welded section of the instrumentation tube support while preventing increased device size and complexity.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. In addition, the present invention is not limited by the embodiment. Moreover, components in the embodiment below include components that can be easily substituted by a person skilled in the art and substantially the same components as the components in the embodiment below.

FIG. 1is a schematic configuration view of an example of a nuclear power plant,FIG. 2is a longitudinal cross-sectional view of a pressurized water reactor, andFIG. 3is a cross-sectional view showing an instrumentation tube support of a reactor vessel.

The nuclear power plant shown inFIG. 1includes a Pressurized Water Reactor (PWR). In the nuclear power plant, a reactor vessel101, a pressurizer102, a steam generator103, and a primary cooling water pump104of the pressurized water reactor are sequentially connected by a primary cooling water tube105in a reactor container100, and thus, a circulating path of primary cooling water is configured.

The reactor vessel101stores a fuel assembly120in the inner portion of the reactor vessel in a sealed state, and includes a reactor vessel main body101aand a reactor vessel cover101bmounted on the upper portion of the reactor vessel main body so that the fuel assembly120may be inserted and extracted. An inlet side tube support101cand an outlet side tube support101dthat supply and discharge light water serving as the primary cooling water are provided on the upper portion of the reactor vessel main body101a. The outlet side tube support101dis connected to the primary cooling water tube105so as to communicate with an inlet side water chamber103aof the steam generator103. Moreover, the inlet side tube support101cis connected to the primary cooling water tube105so as to communicate with an outlet side water chamber103bof the steam generator103.

In the steam generator103, in the lower portion which is hemispherically formed, the inlet side water chamber103aand the outlet side water chamber103bare provided so as to be partitioned by a partition plate103c. The inlet side water chamber103aand the outlet side water chamber103bare partitioned from the upper portion side of the steam generator103by a tube plate103dthat is provided on the top portion. An inverted U-shaped heat transfer tube103eis provided on the upper portion side of the steam generator103. End portions of the heat transfer tube103eare supported by the tube plate103dso as to connect the inlet side water chamber103aand the outlet side water chamber103bto each other. Moreover, the inlet side water chamber103ais connected to the inlet side primary cooling water tube105, and the outlet side water chamber103bis connected to the outlet side primary cooling water tube105. Moreover, in the steam generator103, an outlet side secondary cooling water tube106ais connected to the upper end of the upper portion side partitioned by the tube plate103d, and an inlet side secondary cooling water tube106bis connected to the side portion of the upper portion side.

Moreover, in the nuclear power plant, the steam generator103is connected to a steam turbine107via the secondary cooling water tubes106aand106boutside the reactor container100, and thus, a circulating path of secondary cooling water is configured.

The steam turbine107includes a high pressure turbine108and a low pressure turbine109, and a generator110is connected to the steam turbine. Moreover, a water separation heater111branches from the secondary cooling water tube106aand is connected to the high pressure turbine108and the low pressure turbine109. In addition, the low pressure turbine109is connected to a condenser112. The condenser112is connected to the secondary cooling water tube106b. As described above, the secondary cooling water tube106bis connected to the steam generator103and reaches the steam generator103from the condenser112, and a condensate pump113, a low pressure feed water heater114, a deaerator115, a main feed pump116, and a high pressure feed water heater117are provided in the secondary cooling water tube.

Accordingly, in the nuclear power plant, the primary cooling water is heated in the reactor vessel101to reach a high temperature and a high pressure, is pressurized by the pressurizer102, and is supplied to the steam generator103via the primary cooling water tube105while a constant pressure of the primary cooling water is maintained. In the steam generator103, the secondary cooling water is evaporated by heat exchange between the primary cooling water and the secondary cooling water, and thus, steam is generated. The primary cooling water that is cooled after the heat exchange is recovered to the primary cooling water pump104side via the primary cooling water tube105, and is returned to the reactor vessel101. Meanwhile, the secondary cooling water becoming steam generated by the heat exchange is supplied to the steam turbine107. With respect to the steam turbine107, the water separation heater111removes water from the steam exhausted from the high pressure turbine108, and after the steam is further heated to be overheated, the steam is fed to the low pressure turbine109. The steam turbine107is driven by the steam of the secondary cooling water, the power is transmitted to the generator110, and thus, electricity is generated. The steam supplied to drive the turbine is discharged to the condenser112. Heat exchange between cooling water (for example, sea water) fed via an intake tube112aby a pump112band the steam discharged from the low pressure turbine109is performed by the condenser112, and the steam is condensed so as to be returned to a low-pressure saturated liquid. The cooling water used in the heat exchange is discharged from a drain tube112c. In addition, the condensed saturated liquid becomes the secondary cooling water, and is fed outside the condenser112via the secondary cooling water tube106bby the condensate pump113. In addition, for example, after the secondary cooling water passing through the secondary cooling water tube106bis heated by low pressure steam bled from the low pressure turbine109at the low pressure feed water heater114and impurities of the secondary cooling water such as dissolved oxygen or non-condensable gas (ammonia gas) are removed by the deaerator115, the secondary cooling water is fed by the main feed pump116, and for example, after the secondary cooling water is heated by the high pressure steam bled from the high pressure turbine108at the high pressure feed water heater117, the secondary cooling water is returned to the steam generator103.

In the pressurized water reactor of the nuclear power plant configured as above, as shown inFIG. 2, the reactor vessel cover101bis fixed to the reactor vessel main body101aso as to be openable and closable by a plurality of stud bolts121and nuts122so that the in-core structure including the fuel assembly120may be inserted into the inner portion of the reactor vessel101.

The reactor vessel main body101ais formed in a cylindrical shape in which the upper portion can be opened by removing the reactor vessel cover101b, and the lower portion is closed by a lower head101ehaving a hemispherical shape. In the reactor vessel main body101a, an upper reactor core support plate123is fixed to the inner portion of the reactor vessel main body101aabove the inlet side tube support101cand the outlet side tube support101d, and a lower reactor core support plate124is positioned in the vicinity of the lower head101epositioned at the lower portion is fixed to the inner portion of the reactor vessel main body101a. The upper reactor core support plate123and the lower reactor core support plate124are formed in disk shapes, and a plurality of communication holes (not shown) are formed on the plates123and124. Moreover, the upper reactor core support plate123is connected to an upper reactor core plate126, on which a plurality of communication holes (not shown) are formed, downward via a plurality of reactor core support rods125.

In the inner portion of the reactor vessel main body101a, a reactor core tank127having a cylindrical shape is disposed at a predetermined distance from the inner wall surface, the upper portion of the reactor core tank127is connected to the upper reactor core plate126, and the lower portion of the reactor core tank127is connected to a lower reactor core plate128that is formed in a disk shape and on which a plurality of communication holes (not shown) are formed. In addition, the lower reactor core plate128is supported by the lower reactor core support plate124. That is, the reactor core tank127is supported by the lower reactor core support plate124of the reactor vessel main body101a.

The reactor core129is formed of the upper reactor core plate126, the reactor core tank127, and the lower reactor core plate128. The plurality of fuel assemblies120are disposed inside the reactor core129. The fuel assembly120is configured so that a plurality of fuel rods (not shown) are bundled in a lattice shape by support lattices, an upper nozzle is fixed to the upper end portion, and a lower nozzle is fixed to the lower end portion. In addition, a plurality of control rods130are disposed inside the reactor core129. The upper end portions of the plurality of control rods130are collected to form a control rod cluster131, and the plurality of control rods130can be inserted into the fuel assembly120. A plurality of control rod cluster guide-tubes132penetrating the upper reactor core support plate123are fixed to the upper reactor core support plate123, and the lower end portion of each control rod cluster guide-tube132extends to the control rod cluster131inside the fuel assembly120.

The upper portion of the reactor vessel cover101bconfiguring the reactor vessel101is formed in a hemispherical shape and a magnetic jack type control rod driving device133is provided on the upper portion, and the control rod driving device133is accommodated in a housing134that is integrally formed with the reactor vessel cover101b. The upper end portions of the plurality of control rod cluster guide-tubes132extend to the control rod driving device133, and a control rod cluster driving shaft135extending from the control rod driving device133extends to the fuel assembly120through the control rod cluster guide-tube132and can hold the control rod cluster131.

The control rod driving device133extends in the up-down direction and is connected to the control rod cluster131, and the control rod driving device133vertically moves the control rod cluster driving shaft135, in which a plurality of circumferential grooves are disposed on the surface of the shaft135at a uniform pitch in the longitudinal direction, by the magnetic jack, and thus, controls the output of the reactor.

Moreover, in the reactor vessel main body101a, a plurality of instrumentation tube supports136penetrating the lower head101eare provided, and in each instrumentation tube support136, an in-core instrumentation guide tube137is connected to the upper end portion inside the reactor, and a conduit tube138is connected to the lower end portion outside the reactor. The upper end portion of each in-core instrumentation guide tube137is connected to the lower reactor core support plate124, and upper and lower connection plates139and140are attached to the in-core instrumentation guide tube137to prevent vibration. A thimble tube141, on which a neutron flux detector (not shown) capable of measuring a neutron flux is mounted, penetrates the lower reactor core plate128through the instrumentation tube support136and the in-core instrumentation guide tube137from the conduit tube138, and can be inserted into the fuel assembly120.

Accordingly, the control rod cluster driving shaft135is moved by the control rod driving device133so that the control rod130is extracted from the fuel assembly120by a predetermined amount, nuclear fission in the reactor core129is controlled, the light water filling the reactor vessel101is heated by the generated heat energy, the high-temperature light water is discharged from the outlet side tube support101d, and as described above, the high-temperature light water is fed to the steam generator103. That is, neutrons are emitted by the nuclear fission of nuclear fuels configuring the fuel assembly120, the light water serving as the moderator and the primary cooling water decrease kinetic energy of the emitted high-speed neutrons to generate thermal neutrons, and the light water easily generates new nuclear fission and absorbs the generated heat, and the fuel assembly is cooled. Meanwhile, the control rod130is inserted into the fuel assembly120, and thus, the number of neutrons generated in the reactor core129is adjusted, and all control rods130are inserted into the fuel assembly120, and thus, it is possible to urgently stop the reactor.

Moreover, in the reactor vessel101, an upper plenum142that communicates with the outlet side tube support101dis formed on the upper portion of the reactor core129, and a lower plenum143is formed on the lower portion thereof. In addition, the inlet side tube support101cand a downcomer portion144communicating with the lower plenum143are formed between the reactor vessel101and the reactor core tank127. Accordingly, the light water flows into the reactor vessel main body101afrom the inlet side tube support101c, flows downward along the downcomer portion144to reach the lower plenum143, and rises to be guided upward by the spherical inner surface of the lower plenum143. In addition, after the light water passes through the lower reactor core support plate124and the lower reactor core plate128, the light water flows into the reactor core129. The light water flowing into the reactor core129absorbs the heat energy generated from the fuel assembly120configuring the reactor core129, and thus, the light water cools the fuel assembly120to reach a high temperature, passes through the upper reactor core plate126, rises up to the upper plenum142, and is discharged through the outlet side tube support101d.

In the reactor vessel101configured as above, as shown inFIG. 3, the instrumentation tube support136is configured so that an in-core instrumentation tube145is fitted into a mounting hole146formed on the lower head101eof the reactor vessel main body101a, and is fixed to the inner surface of the lower head101eby welding (groove welded section147). In the reactor vessel main body101a, stainless steel is build-up welded to the inner surface of a low alloy steel which is a base material, and in a state where the in-core instrumentation tube145made of a nickel-based alloy is fitted to the mounting hole146of the reactor vessel main body101a, the in-core instrumentation tube145is welded to the reactor vessel main body101a(by the groove welded section147) with the material made of a nickel-based alloy.

Accordingly, tensile stress may remain on the instrumentation tube support136(the in-core instrumentation tube145), and the groove welded section147and the periphery of the groove welded section, and thus, probability of occurrence of stress corrosion cracking due to long-time use becomes higher. Therefore, by a water jet peening device serving as a reactor repair device, tensile residual stress on the surface of the instrumentation tube support136(in-core instrumentation tube145) to be repaired or the surface (inner surface) of the lower head101ewhich is the groove welded section147and the periphery of the groove welded section is improved so as to be compression residual stress, and thus, the stress corrosion cracking is prevented. The water jet peening device sprays high-pressure water including cavitation bubbles on the surface of a metal member in water, and thus, the tensile residual stress on the surface of the metal member is improved so as to be the compression residual stress.

Moreover, when the tensile residual stress on the surface of the in-core instrumentation tube145or the surface of the lower head101eis improved so as to be the compression residual stress by the water jet peening device, the water jet peening device is mounted on the instrumentation tube support136(in-core instrumentation tube145) and the work is performed.

FIG. 4is a schematic view showing the installation state of the water jet peening device,FIG. 5is a front view of the water jet peening device,FIG. 6is a side view (when viewed from arrow A ofFIG. 5) showing a lifting mechanism of the water jet peening device,FIG. 7is a front view showing a spray nozzle of the water jet peening device,FIG. 8is a plane cross-sectional view (cross-sectional view taken along B-B ofFIG. 7) showing a rotation mechanism of the water jet peening device,FIG. 9is a plane cross-sectional view (cross-sectional view taken along C-C ofFIG. 7) showing the rotation mechanism of the water jet peening device, andFIG. 10is a side view (when viewed from arrow D ofFIG. 7) showing the rotation mechanism of the water jet peening device.

As shown inFIG. 4, a water jet peening device1is fixed to the instrumentation tube support136(in-core instrumentation tube145) provided on the lower head101eof the reactor vessel101(reactor vessel main body101a).

Moreover, in the nuclear power plant, a work floor151is provided on a reactor building (not shown), a cavity152is provided below the work floor151, and cooling water is stored in the cavity152. The reactor vessel101is disposed inside the cavity152, and the reactor vessel101is supported in a suspended manner. In the reactor building, a pair of parallel guide rails155is provided on both sides of the cavity152, and a mobile crane156is movably supported by the rails155. The mobile crane156is movable in one direction (right-left direction inFIG. 4) in the horizontal direction, and an electric hoist157that is movable in the other direction (a direction orthogonal to the paper surface inFIG. 4) intersecting (orthogonal to) the one direction in the horizontal direction is provided in the mobile crane156. In addition, the electric hoist157includes a hook158which can be lifted and lowered in the vertical direction. An installation pole159is suspended via the hook158.

The installation pole159is a long member and has a predetermined length, and the water jet peening device1can be connected to the lower end portion of the installation pole159. The installation pole159is configured of a plurality of division poles, and the flanges of the upper ends and the lower ends of the division poles come into close contact with each other, and it is possible to fasten the upper ends and the lower ends by a plurality of swing bolts.

As shown inFIG. 5, the water jet peening device1includes a device main body2, a positioning member3, and a spray nozzle4. The positioning member3is disposed to protrude downward from the lower portion of the device main body2and is fitted so as to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), and thus, the device main body2is fixed to the instrumentation tube support136.

As shown inFIG. 5, the spray nozzle4is provided in the device main body2, and sprays the high-pressure water on the outer surface of the instrumentation tube support136(in-core instrumentation tube145), the inner surface of the lower head101e, and the groove welded section147. A high-pressure water supply tube4ato which the high-pressure water is supplied is connected to the spray nozzle4. As shown inFIG. 4, the high-pressure water supply tube4ais connected to a high-pressure water pump160that is installed on the work floor151and feeds the high-pressure water. Moreover, a spray port4bis provided on the lower end portion of the spray nozzle4. The spray nozzle4is provided so as to be movable by a swiveling mechanism5, a lift mechanism6, and a rotation mechanism7which are three movement mechanisms.

The swiveling mechanism5swivels the spray nozzle4in the horizontal direction centered on the positioning member3. The positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), and thus, the center of the swiveling of the swiveling mechanism5is coincident with a central axis C of the instrumentation tube support136(in-core instrumentation tube145). That is, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the swiveling mechanism5swivels the spray nozzle4centered on the central axis C of the instrumentation tube support136(in-core instrumentation tube145).

As shown inFIG. 5, the swiveling mechanism5includes a swiveling motor5aabove the device main body2. A driving gear5bis provided on the output shaft of the swiveling motor5a. In addition, the swiveling mechanism5includes a swivel shaft5cabove the device main body2. The swivel shaft5cis provided parallel to the output shaft of the swiveling motor5a, is connected to the upper portion of the device main body2, and is rotatably provided with respect to the installation pole159. Moreover, a driven gear5dthat meshes with the driving gear5bof the swiveling motor5ais provided on the swivel shaft5c. The rotation center of the swivel shaft5cand the rotation center of the driven gear5dare coincident with each other centered on the positioning member3. In addition, when the swiveling motor5ais driven, the rotation is transmitted from the driving gear5bto the driven gear5d, and the swivel shaft5cis rotated centered on the positioning member3which accompanies the device main body2. Accordingly, the spray nozzle4provided in the device main body2is swiveled centered on the positioning member3. That is, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the spray nozzle4is swiveled centered on the instrumentation tube support136(in-core instrumentation tube145).

The lift mechanism6raises and lowers the spray nozzle4in the vertical direction with respect to the positioning member3. The positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), and thus, the device main body2is fixed to the instrumentation tube support136. That is, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the lift mechanism6lifts and lowers the spray nozzle4so that the spray nozzle4approaches or moves away from the instrumentation tube support136(in-core instrumentation tube145), the inner surface of the lower head101e, and the groove welded section147.

As shown inFIG. 6, the lift mechanism6includes a lifting motor6athat is fixed to the device main body2. A ball screw6bis provided on the output shaft of the lifting motor6a. The ball screw6bis provided to extend in the up-down direction, and is rotatably provided with respect to the device main body2. When the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the ball screw6bis parallel with the central axis C of the instrumentation tube support136(in-core instrumentation tube145) and extends in the vertical direction. In addition, the lift mechanism6includes a rail6cthat is provided to extend parallel to the ball screw6band is fixed to the device main body2. A slider6dthat is movable in the extension direction of the rail6cis provided on the rail6c. A slide frame6eis fixed to the slider6d. Moreover, a nut portion6fthat is screwed to the ball screw6bis fixed to the slide frame6e. In addition, the spray nozzle4is fixed to the slide frame6e. The high-pressure water supply tube4athat is connected to the spray nozzle4is supported by the slide frame6evia the support portion6g. When the lifting motor6ais driven, the ball screw6bis rotated, and the nut portion6fis slidably moved along the extension direction of the rail6cwhich accompanies the slide frame6eby the rotation. That is, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the spray nozzle4is lifted and lowered along the extension direction of the central axis C of the instrumentation tube support136(in-core instrumentation tube145).

The rotation mechanism7rotates the spray nozzle4. Specifically, as shown inFIG. 7, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), the rotation mechanism7rotates the spray nozzle4centered on a rotation shaft center S that is inclined at a predetermined angle α (for example, 17.5°) with respect to the vertical direction along the central axis C of the instrumentation tube support136(in-core instrumentation tube145).

The rotation mechanism7is attached to the device main body2, and includes a rotation shaft7bextending along the rotation shaft center S on a base portion7afixed to the device main body2. The rotation shaft7bis rotatably provided with respect to the base portion7a, the spray nozzle4is attached to the rotation shaft7b, and the rotation shaft7bis rotated centered on the rotation shaft center S accompanied by the spray nozzle4.

Moreover, the rotation mechanism7includes restricting means for restricting the spray nozzle4so that the rotational movement of the spray nozzle4is reversed at 180°. As shown inFIGS. 7 and 8, the restricting means includes an abutting portion7cthat is provided on the spray nozzle4which is the movement side, and a stopper7dthat is provided on the base portion7aof the rotation mechanism7which is the fixed side. The stoppers7dare disposed so that positions are displaced at 180° centered on the rotation shaft center S. In addition, the abutting portion7cabuts the stopper7daccording to the rotational movement of the spray nozzle4, and thus, the rotational movement of the spray nozzle4is restricted to be reversed at 180°.

In addition, as shown inFIG. 9, in order to rotate the spray nozzle4centered on the rotation shaft center S, the rotation mechanism7includes a pinion gear7ethat is provided on the rotation shaft7b. The pinion gear7emeshes with the rack gear7f. The rack gear7fis provided so as to slidingly move with respect to the base portion7a, and rotates the pinion gear7ewhich accompanies the rotation shaft7bby the sliding movement. The rack gear7fis connected to a cylinder rod7hof a cylinder7gand slidingly moves accompanied by sliding of the cylinder rod7h. That is, when the cylinder7gis driven, the rack gear7fslidingly moves, the rotation shaft7bis rotated accompanied by the rotation of the pinion gear7e, and the spray nozzle4is rotated centered on the rotation shaft center S. In addition, a slide moving range (a rotational movement range of the rotation shaft7b) of the rack gear7fmoved by the cylinder7gis set so as to be greater than the rotational movement range of the spray nozzle4which is restricted by the above-described restricting means (the abutting portion7cand the stopper7d).

In addition, in the rotation mechanism7, a magnet7iis provided on the connection portion between the cylinder rod7hof the cylinder7gand the rack gear7f. The magnet7islidingly moves along with the slide movement of the rack gear7fmoved by the cylinder7g. Magnetic detection sensors7jfor detecting the magnetism of the magnet7iare provided on both end portions in the slide movement of the magnet7i. The position of each magnetic detection sensor7jcorresponds to the slide moving range of the rack gear7fin the rotational movement range of the spray nozzle4restricted by the above-described restricting means (abutting portion7cand stopper7d). Accordingly, the slide position of the rack gear7fat which the magnetism of the magnet7iis detected by each magnetic detection sensor7jbecomes the rotation position of the spray nozzle4restricted by the restricting means (abutting portion7cand stopper7d), and this rotation position is detected.

In addition, as shown inFIG. 6, in the rotation mechanism7, the rotation shaft7bis supported so as to be rotated with respect to the base portion7a, and the spray nozzle4is provided so as to be rotated. Moreover, an introduction path7kthat introduces the high-pressure water supplied from the high-pressure water supply tube4ais provided in the inner portion of the base portion7a. Meanwhile, a communication path7mthrough which the introduction path7kand the spray port4bcommunicate with each other is provided in the inner portion of the rotation shaft7b. Moreover, in the portion of the base portion7aat which the rotation shaft7bis supported so as to rotate, a sealing material7nwhich seals the communication portion between the introduction path7kand the communication path7mis provided. That is, the high-pressure water supplied from the high-pressure water supply tube4ais introduced into the introduction path7k, and is sprayed from the spray port4bvia the communication path7m. Moreover, the spray nozzle4rotates centered on the rotation shaft center S (rotation shaft7b). Moreover, the introduction path7kis provided on the base portion7awhich is the fixed side, the communication path7mis provided on the rotation shaft7bwhich is the rotating side, but the mutual communication portion is sealed by the sealing material7n. Accordingly, the high-pressure water supply tube4asupplying the high-pressure water can be connected to the introduction path7kprovided in the base portion7awhich is the fixed side, torsion does not occur in the high-pressure water supply tube4awhen the spray nozzle4is rotated, and the high-pressure water can be sprayed from the spray port4bwithout being leaked outside the rotation shaft7bby the sealing material7n. That is, the rotation mechanism7rotatably supports the spray nozzle4by a so-called swivel joint.

In the spray nozzle4that is attached to the rotation shaft7b, the spray port4bis provided toward the rotation shaft center S side in the direction that is inclined with respect to the rotation shaft center S. Specifically, as shown inFIG. 7, in each reversed position at which the rotational movement is restricted at 180° by the restricting means (abutting portion7cand stopper7d), the spray port4bis provided toward the rotation shaft center S side in the direction that is inclined at a predetermined angle β (for example, 12.5°) with respect to the rotation shaft center S. That is, the high-pressure water is sprayed in this direction.

For example, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), since the spray port4bshown by a solid line inFIG. 7is inclined at a predetermined angle β (for example, 12.5°) outside (the side away from the central axis C) the rotation shaft center S with respect to the rotation shaft center S inclined at a predetermined angle α (for example, 17.5°) to the central axis C, the high-pressure water is sprayed obliquely downward from above at an angle θ (for example, 30°) of the predetermined angle α+the predetermined angle β with respect to the surface which is vertical along the central axis C. This angle is within a range of 30° to 90° which is the spray angle of the high-pressure water suitable for the water jet peening. That is, it is possible to spray the high-pressure water on the outer surface of the instrumentation tube support136(in-core instrumentation tube145) that is vertically provided along the central axis C, or on the inner surface nearly vertical with respect to the hemispherical lower head101eto the inner surface that is inclined 60° or more with respect to the vertical surface, for example, at a suitable angle.

Meanwhile, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), since the spray port4bshown by a two-dot chain line inFIG. 7is inclined at the predetermined angle (for example, 12.5°) inside (the side close to the central axis C) the rotation shaft center S with respect to the rotation shaft center S inclined at the predetermined angle α (for example, 17.5°) to the central axis C, the high-pressure water is sprayed downward from above at an angle δ (for example, 85°) with respect to the horizontal surface orthogonal to the central axis C at the angle of the predetermined angle α—the predetermined angle β. This angle is within a range of 30° to 90° which is the spray angle of the high-pressure water suitable for the water jet peening. That is, it is possible to spray the high-pressure water on the horizontal inner surface in the hemispherical lower head101eto the inner surface that is inclined 55° or more with respect to the horizontal surface, for example, at a suitable angle.

In addition, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), in the spray port4bof the spray nozzle4, the distance from the central axis C at each reversed position to the spray position in the horizontal direction is appropriately set. Specifically, inFIG. 7, a distance H1in the horizontal direction from the central axis C to the spray position on the outer surface of the instrumentation tube support136(in-core instrumentation tube145), or a distance H2in the horizontal direction from the central axis C to the spray position on the inner surface of the lower head101eis determined by the design value of each instrumentation tube support136, and the design value is commonly used for all instrumentation tube supports136. Accordingly, the position of the spray port4bof the spray nozzle4is set so that the distances H1and H2are set. In the water jet peening device1of the present embodiment, in the rotation mechanism7, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), as shown inFIG. 7, the spray nozzle4is supported so as to rotate centered on the rotation shaft center S which is downwardly inclined to the instrumentation tube support136side (positioning member3side) in the vertical direction, and the spray port4bis disposed toward the rotation shaft center S side in the direction that is inclined with respect to the rotation shaft center S. Accordingly, when the spray nozzle4is rotated as shown by the solid line inFIG. 7, the high-pressure water reaches the position of the distance H1close to the central axis C, and when the spray nozzle4is rotated as shown by the two-dot chain line inFIG. 7, the high-pressure water reaches the position of the distance H2away from the central axis C. In addition, the angle α and the angle β are set so that the relationship between the distances H1and H2is coincident with the design value of the instrumentation tube support136. As a result, it is possible to perform the water jet peening on two locations of the outer surface of the instrumentation tube support136(in-core instrumentation tube145) and the inner surface of the lower head101eby the rotation of the spray nozzle4.

In addition, when the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), a distance L1shown by a solid line inFIG. 7from the spray port4bto the outer surface of the instrumentation tube support136(in-core instrumentation tube145) or a distance L2shown by a two-dot chain line inFIG. 7from the spray port4bto the inner surface of the lower head101eis adjusted by the lift mechanism6. The distances L1and L2are set to 130 mm±10 mm, which are the spray distance of the high-pressure water suitable for the water jet peening. In the state where the positioning member3is fitted to clamp the upper end of the instrumentation tube support136(in-core instrumentation tube145), since the position in the vertical direction of the spray nozzle4is determined by the reference position (for example, the uppermost position) set by the lift mechanism6and the design value of each instrumentation tube support136, after the position of the spray nozzle4is determined, it is possible to appropriately adjust the spray distance by the lifting and lowering position of the spray nozzle4performed by the lift mechanism6.

Moreover, as shown inFIG. 5, in the water jet peening device1, an application monitoring camera8is provided on the positioning member3which is the device main body2side. The application monitoring camera8is fixed to the positioning member3, is provided so as to be swiveled along with the spray nozzle4by the swiveling mechanism5, and can photograph the spray state of the high-pressure water performed by the spray nozzle4.

Here, a method of applying the water jet peening device1with respect to the outer surface of the instrumentation tube support136(in-core instrumentation tube145), and a method of applying the water jet peening with respect to the inner surface of the lower head101ewill be described.

As shown inFIG. 4, in a state where the cooling water is stored in the cavity152, the water jet peening device1is suspended via the installation poles159by the mobile crane156. From here, the water jet peening device1is moved in the horizontal direction by the mobile crane156, and the water jet peening device1is lowered by the electric hoist157while being positioned with respect to the instrumentation tube support136.

In addition, as shown inFIG. 5, the positioning member3is positioned at the upper end of the instrumentation tube support136, and thus, the water jet peening device1is fixed to the instrumentation tube support136.

If the water jet peening device1is fixed to the instrumentation tube support136, monitoring is performed by the application monitoring camera8, the spray nozzle4is rotated by the rotation mechanism7in accordance with the application with respect to the outer surface of the instrumentation tube support136(in-core instrumentation tube145) and the application with respect to the inner surface of the lower head101e, the height position of the spray nozzle4is adjusted by the lift mechanism6while swiveling the spray nozzle4by the swiveling mechanism5in the state where the high-pressure water is sprayed, and thus, the high-pressure water including the cavitation bubbles is sprayed on the outer surface of the instrumentation tube support136(in-core instrumentation tube145) or the inner surface of the lower head101e. Accordingly, the tensile residual stress on the outer surface of the instrumentation tube support136(in-core instrumentation tube145) or the inner surface of the lower head101eis improved so as to be the compression residual stress.

In this way, in the water jet peening device1of the present embodiment, there is provided a water jet peening device1in which the spray nozzle4is provided along with the positioning member3positioned at the upper end of the instrumentation tube support136, and the water jet is sprayed from the spray port4bof the spray nozzle4, including: the swiveling mechanism5that swivels the spray nozzle4in the horizontal direction centered on the positioning member3positioned at the upper end of the instrumentation tube support136; the lift mechanism6that raises and lowers the spray nozzle4in the vertical direction with respect to the positioning member3positioned at the upper end of the instrumentation tube support136; and the rotation mechanism7that supports the spray nozzle4so as to be able to rotate centered on the downward-inclined rotation shaft center S on the positioning member3side in the vertical direction, disposes the spray port4baimed toward the rotation shaft center S side in the direction that is inclined with respect to the rotation shaft center S, and rotates the spray nozzle4centered on the rotation shaft center S.

According to the water jet peening device1, in the rotation mechanism7, the spray nozzle4is supported so as to be able to rotate centered on the downward-inclined rotation shaft center S on the positioning member3side in the vertical direction, the spray port4bis disposed aimed toward the rotation shaft center S side in the direction that is inclined with respect to the rotation shaft center S, and the spray nozzle4is rotated centered on the rotation shaft center S. Accordingly, a state where the spray port4bis disposed in the direction inclined at a predetermined angle from the vertical direction at the position at which the distance in the horizontal direction from the positioning member3side is relatively long, and a state where the spray port4bis disposed in the vertical direction at the position at which the distance in the horizontal direction from the positioning member3side is relatively short are obtained. Accordingly, it is possible to adjust the position in the horizontal direction by the rotation mechanism7. As a result, according to the configurations of the swiveling mechanism5, the lift mechanism6, and the rotation mechanism7, it is possible to perform the water jet peening on the outer surface of the instrumentation tube support136and the groove welded section147(the inner surface of the lower head101e) of the instrumentation tube support136while preventing an increased size and complexity of the device.

In addition, in the water jet peening device1of the present invention, the rotation mechanism7includes: the rotation shaft7bthat supports the spray nozzle4so as to be able to rotate with respect to a base portion7aof the rotation shaft; the introduction path7kthat is provided in the inner portion of the base portion7aand introduces the high-pressure water; the communication path7mthat is provided in the inner portion of the rotation shaft7band causes the introduction path7kand the spray port4bto communicate with each other; and the sealing material7nthat seals the communication portion between the communication path7mand the introduction path7kwhile allowing the rotation of the rotation shaft7b.

According to the water jet peening device1, it is possible to connect the high-pressure water supply tube4athat supplies the high-pressure water to the introduction path7kprovided in the base portion7awhich is the fixed side, and it is possible to spray the high-pressure water from the spray port4bwhile preventing torsion in the high-pressure water supply tube4afrom being generated when the spray nozzle4is rotated and preventing the high-pressure water from being leaked outside the rotation shaft7bby the sealing material7n.

In addition, in the water jet peening device1of the present embodiment, the rotation mechanism7includes: the pinion gear7ethat is provided in the spray nozzle4centered on the rotation shaft center S; the rack gear7fthat meshes with the pinion gear7e; and the cylinder7gthat slidingly moves the rack gear7f.

Since the application of the water jet peening is performed in water, if a motor or the like is used in the rotation mechanism7, a mechanism or the like having a waterproof function is required, and thus, the increase in the size of the rotation mechanism7occurs. Meanwhile, according to the water jet peening device1of the present embodiment, since the rack gear7fis slidingly moved by the cylinder7gand the pinion gear7eis rotated accompanied by the spray nozzle4, the waterproof function is not required, and it is possible to prevent the increase in the size of the rotation mechanism7.

In addition, the water jet peening device1of the present embodiment includes the restricting means (abutting portion7cand stopper7d) for restricting the rotation of the spray nozzle4at both positions at which the direction of the spray port4bis reversed according to the rotation of the spray nozzle4.

According to the water jet peening device1, since the restricting means (abutting portion7cand stopper7d) is provided, in the configuration in which the rack gear7fis slidingly moved by the cylinder7gand the pinion gear7eis rotated accompanied by the spray nozzle4, both positions at which the direction of the spray port4bis reversed are restricted, and thus, it is possible to move the spray port4btoward the appropriate position.

REFERENCE SIGNS LIST