JP2005308461A - Cleaning method and cleaning device of tubular member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method and a cleaning device for removing effectively at low cost, a clad adhering to the inner surface of a tubular member such as an inlet mixer used for a boiling water reactor. <P>SOLUTION: In this cleaning method of the tubular member, a cleaning unit equipped with a head 24 and a driving device 25 for emitting a pulse laser 45 onto the inner surface of the inlet mixer 5 is installed inside the inlet mixer 5, and a laser oscillator 2 for oscillating the pulse laser 45 and the head 24 are connected together by an optical fiber cable 4, to thereby supply the pulse laser 45 to the head 24, and the head 24 and the driving device 25 are operated by a controller 3, and a spot 46 of the pulse laser 45 is scanned on the inner surface of the inlet mixer 5, to thereby remove the clad adhering to the inner surface of the inlet mixer 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning method and a cleaning device for a tubular member, such as an inlet mixer installed in a boiling water reactor, for removing an inner surface of a tubular member immersed in a liquid and a clad adhering to a nozzle.

A boiling water reactor (BWR) is provided with a coolant recirculation system that generates forced convection in the entire core necessary to obtain a required power density. This coolant recirculation system is a facility for circulating cooling water through a jet pump assembly using a recirculation pump as a drive source. The driving water pressurized by the recirculation pump flows to the inlet mixer and is supplied to the jet pump nozzle of the inlet mixer. In a general BWR, 16 to 24 inlet mixers are arranged.
Japanese Unexamined Patent Publication No. 7-55986 Japanese Unexamined Patent Publication No. 7-55985

  Along with the operation of the nuclear reactor, a clad composed mainly of iron is formed on the inner surface of the inlet mixer. When this clad is deposited, resistance is generated in the cooling water flow, so that the speed of the recirculation pump must be increased to maintain the cooling water flow rate, and the operating cost of the recirculation pump increases. In addition, if the cladding is significantly deposited, the output of the reactor may decrease even if measures such as increasing the speed of the recirculation pump are taken.

  As a method of preventing the influence of the clad adhering to the inlet mixer, there are a method of replacing the inlet mixer with a new one and a method of cleaning the inlet mixer.

  However, when the inlet mixer is replaced, there is a problem that the time and manufacturing cost required to manufacture a new inlet mixer are large, and the reactor must be stopped during the replacement work. In addition, the old inlet mixer that was replaced has a problem of disposal because it is radioactive waste.

  On the other hand, when cleaning an inlet mixer, the cleaning method by a water jet is implemented as a prior art (for example, refer patent document 1 and patent document 2).

  However, in the above prior art, since the structure of the inlet mixer is complicated, it is difficult to stably install the cleaning tool, and generation of radioactive secondary products must be suppressed. It was extremely difficult to establish a reliable cleaning method.

  The present invention has been made in consideration of the above-described circumstances, and is a tubular tube that effectively removes the cladding adhering to the inner surface of a tubular member such as an inlet mixer used in a boiling water reactor at low cost. It is an object of the present invention to provide a member cleaning method and a cleaning device.

  In order to solve the above-described problems, the tubular member cleaning method of the present invention includes a head that irradiates a pulse laser on the inner surface of a tubular member that is immersed in a liquid, and a drive unit that drives the head. A cleaning unit is inserted and fixed in the tubular member, and a pulse laser is oscillated by a laser oscillator connected to the head by an optical fiber cable to supply the pulse laser to the head, and the head and the driving means are controlled by a controller. The clad adhering to the tubular member is removed by scanning the inner surface of the tubular member with a pulse laser spot operated by the above method.

  In order to solve the above-described problems, the tubular member cleaning device of the present invention is installed on the inner surface of a tubular member immersed in a liquid and emits a pulse laser, and a drive for driving the head. A cleaning unit comprising: means; a laser oscillator that oscillates a pulse laser; an optical fiber cable that connects the laser oscillator and the head and supplies the pulse laser to the head; and operates the head and the driving means And a controller for removing the clad by scanning the inner surface of the tubular member with a spot of a pulsed laser.

  According to the method and apparatus for cleaning a tubular member of the present invention, the inner surface of the tubular member can be cleaned in a state where the tubular member is installed at a normal operating position, so that the time required for cleaning is shortened and the cost is reduced. It is possible to reduce.

  In particular, when the tubular member is a boiling water reactor inlet mixer, the inlet mixer and the inner surface of the nozzle can be cleaned in a state where the inlet mixer is installed in the reactor, thereby reducing the cleaning time and cost. .

  Embodiments of a tubular member cleaning method and a cleaning apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following examples, an inlet mixer installed in a boiling water reactor was illustrated as an example of a tubular member. In this embodiment, the tube axis direction indicates the longitudinal direction of the inlet mixer, and the circumferential direction indicates the tube diameter direction of the inlet mixer.

  FIG. 1 shows the configuration of a cleaning apparatus as an embodiment of an apparatus for carrying out the tubular member cleaning method of the present invention.

  The tubular member cleaning apparatus according to the first embodiment includes a cleaning unit 1, a laser oscillator 2 that supplies a laser to the cleaning unit 1, and a controller 3 that controls the cleaning unit 1. The laser oscillator 2 and the cleaning unit 1 are connected by an optical fiber cable 4. In FIG. 1, the cleaning unit 1 is connected to the tip of the optical fiber cable 4 and accommodated in the inlet mixer 5. The tubular member cleaning apparatus of the present embodiment shown in FIG. 1 performs cleaning of the inlet pump in water.

  On the other hand, the cleaning unit 1 and the controller 3 are connected by a power supply line 6 and a signal line 7, and supply power to the cleaning unit 1, while transmitting position information of the cleaning unit 1 to the controller 3 for control. It is the structure to do. In FIG. 1, the power supply line 6, the signal line 7, and the optical fiber cable 4 are each connected to the cleaning unit 1. However, in actual equipment, cables having the same connection destination are integrated. It is preferable in terms of facility management to be installed as a covered cable.

  The laser oscillator 2 is installed on the operating floor 8. As an example of the laser oscillator 2, an AO (acousto-optic) -Q switch Nd: YAG laser oscillator 2 is used. For example, a pulse laser having a wavelength of 1064 nm and a pulse width of about 100 ns is emitted. The operating floor 8 is connected to a gas cylinder 9 as a gas supply device, a pressure regulator 11, a connector 12, and a tube 13, and is configured to gas shield the optical fiber cable 4 and the cleaning unit 1.

  In FIG. 2, the block diagram showing the installation condition to the inlet mixer 5 of the cleaning unit 1 is shown. FIG. 3 is an enlarged view of a portion where the cleaning unit 1 is installed on the inlet mixer 5.

  As shown in FIG. 2, the BWR typical inlet mixer 5 includes a pre-nozzle section 16 connected to an outlet of the elbow 15 and a nozzle section 17 following the pre-nozzle section 16, and hereinafter, a throat section 18, downstream of the fluid (water), The barrel section 19, the flare section 21, and the slip joint 22 are integrally connected in this order. The nozzle section 17 is provided with five nozzles 23 arranged at an equal angle around the axis of the inlet mixer 5.

  In the nozzle section 17, ribs 17 </ b> B are arranged at equal intervals around the axis of the inlet mixer 5 on the outside of the nozzle 23, and this structure forms five secondary inlet openings 17 </ b> A. That is, when the water jet exits the nozzle 23, the water outside the inlet mixer 5 is introduced into the inlet mixer 5 through the secondary inlet opening 17A and mixed with the water from the recirculation pump. .

  A bell mouth 18A is formed at a connection portion between the throat section 18 and the nozzle section 17, and is integrally joined to the rib 17B of the nozzle section.

  The cleaning unit 1 shown in FIG. 3 includes a head 24 and a driving device 25. The head 24 is a cleaning function component having a laser irradiation mechanism. The driving device 25 integrally joined coaxially with the head 24 has a function of driving the head 24 in the tube axis direction of the inlet pump 5. FIG. 3 shows a state in which the head 24 is inserted into the nozzle 23 by the driving device 25.

  FIG. 4 is a sectional view showing the detailed structure of the head 24.

  The head 24 shown in FIG. 4 includes an optical processing system that processes a pulse laser introduced by the optical fiber cable 4 and a driving unit that rotates the head 24. A motor 29 and a gear 30 are included as components of the driving unit. A bearing 31 is provided. Further, the optical processing system includes a collimating lens 32, a condensing lens 33, a mirror 34, and a window 35 as constituent elements. These components are housed in the housing 36, and the head 24 is integrally formed. The casing 36 is waterproofed to prevent water from entering the head 24. The head 24 includes a signal line 7 and a power supply line 6 for outputting position information of the optical processing system to control the driving means. The signal line 7 and the power supply line 6 are input to the driving device 25 described above. Are connected independently.

  The optical fiber cable 4 includes an optical fiber cable core wire 27 and a protective tube 28 covering the optical fiber cable core wire 27. The optical fiber cable core 27 is a member having a function of transmitting a laser. As a specific material, for example, a step index (SI) type optical fiber cable having a quartz core is preferably used. The protective tube 28 has a function of protecting the optical fiber cable core wire 27 from an external impact, and gas from the gas supply device is fed into the protective tube 28.

  The laser oscillator 2 and the head of the cleaning unit 1 are connected to each other by being connected to an optical fiber cable 4. The optical fiber cable 4 is inserted into the inlet mixer 5 through the second inlet opening 17 </ b> A shown in FIG. 3, and the head 24 connected to the tip of the optical fiber cable 4 is inserted into the nozzle 23.

  In FIG. 4, in order to clarify the detailed structure of the head 24, the power supply line 7, the signal line 6, and the optical fiber cable are illustrated as being independent. However, in an actual facility, these cables are integrated. It is preferable to use a unified cable.

  On the other hand, as shown in FIG. 3, the drive device 25 connected to the head 24 enables the head 24 to move in the tube axis direction of the inlet mixer 5. The driving device 25 includes a motor 38, a ball screw 39, and a cylinder portion 40. The ball screw 39 is rotated by the motor 38 to push up the cylinder portion 40 in the tube axis direction, and is fixed integrally with the cylinder portion 40. The head 24 is pushed up in the tube axis direction of the inlet mixer 5 and inserted into the nozzle 23. At this time, the cleaning unit 1 is accurately positioned by the holder 41 so that the central axis of the head 24 coincides with the central axis of the nozzle 23.

  The drive device 25 shown in FIG. 3 shows an embodiment of the drive mechanism, and the drive device 25 is shown in this embodiment as long as the head 24 can be inserted into the nozzle 23. It is not limited to the configuration and mechanism.

  The holder 41 is a member provided for positioning the cleaning unit 1 and is not particularly limited in shape, but the holder 41 of the present embodiment is integrally attached to the driving device 25 of the cleaning unit 1, It is a member formed so as to be located on the side of the head portion 24. That is, the relative position in the inlet mixer 5 of the cleaning unit 1 is fixed by the holder 41, and the head 24 is moved in the tube axis direction of the inlet mixer by the driving device 25.

  When inserting the cleaning unit 1, the holder 41 is held and the cleaning unit 1 is inserted into the inlet mixer 5, and installed at the cleaning portion on the inner surface of the inlet mixer 5. At this time, the hook 41A provided on the holder 41 engages with the bell mouth 18A of the inlet mixer 5, the tip of the holder 41 abuts against the inner surface of the barrel section 19, and the side surface of the holder 41 contacts the rib 17B. By fixing so as to be in contact with each other, the driving device 25 attached integrally with the holder 41 is fixed in the inlet mixer 5. By fixing the driving device 25, the head 24 is accurately positioned so that the central axis coincides with the central axis of the nozzle 23. Thereby, the operation of inserting the head 24 into the nozzle 23 by the driving force of the driving device 25 becomes possible.

  In addition, the signal line 7 and the power supply line 6 are independently connected to the head 24 and the driving device 25, respectively, but as shown in FIG. 3, the signal line 7 and the power supply connected to the driving device 25 are connected. The line 6 is integrated into one cable 43, while the signal line 7 and the power supply line 6 connected to the head 24 are accommodated in the protective tube 28 and integrated with the optical fiber cable 4. One cable 44 is used.

  The controller 3 installed on the operating floor 8 is supplied with the signal lines 7 of the laser oscillator 2, the head 24, the driving device 25, and the pressure regulator 11, and based on the input positional information of the head 24. Perform laser output control.

  The cable 43 and the cable 44 are inserted into the inlet mixer 5 through the second inlet opening 17A of the inlet mixer 5, and connect the controller 3 and each component device to each other.

  Next, the operation of the cleaning unit 1 will be described.

  The pulse laser 45 generated by the laser oscillator 2 is introduced into the optical fiber cable core 27 of the optical fiber cable 4 by the optical fiber cable incident unit in the laser oscillator 2. The introduced pulse laser 45 is transmitted through the inside of the optical fiber cable core 27 and emitted from the end face of the optical fiber cable core 27 in the head 24. The pulse laser 45 emitted from the end face is converted into quasi-parallel light by the collimator lens 32, reflected by the mirror 34 while being converged by the condenser lens 33, and emitted from the window 35 to the outside of the head 24. The pulse laser 45 emitted from the window 35 is transmitted through water to irradiate the inner surface of the nozzle 23 as a spot 46 with an underwater transmission distance 47.

The energy density of the pulse laser 45 on the laser irradiation surface is preferably in the range of 0.34 J / cm ^{2 to} 0.85 J / cm ² . According to the pulse laser 45 set to this energy density, various phenomena such as evaporation of the melt due to evaporation and reaction force, separation due to thermal vibration, and removal due to the pressure of the induced plasma occur on the laser irradiation surface. Then, the clad is effectively removed from the inner surface of the nozzle 23.

  The rotational driving force of the motor 29 built in the head 24 is transmitted by the gear 30, and the upper part of the head 24 including the condenser lens 33, the mirror 34, and the window 35 passes through the bearing 31 around the central axis of the head 24. And turn smoothly. Due to this turning motion, the spot 46 of the pulse laser 45 is rotationally scanned in the tube diameter direction of the nozzle 23.

  On the other hand, the rotational driving force of the motor 38 of the driving device 25 drives the ball screw 39 to translate the head 24 in the vertical direction along the central axis. Due to this translational movement, the spot 46 of the pulse laser 45 is translationally scanned in the tube axis direction of the nozzle 23.

  By the combination of the above-described swirl movement and translation movement, the spot 46 of the pulse laser 45 is scanned along the spiral path on the inner surface of the nozzle 23. By this scanning, the entire inner surface of the nozzle 23 can be efficiently cleaned to remove the clad.

  The high-pressure gas accumulated in the gas cylinder 9 is adjusted in pressure by the pressure regulator 11, then passes through the tube 13, is introduced into the protective tube 28 of the optical fiber cable 4 through the connector 12, and the head 24 To the inside. The pressure of the introduced gas is set higher than the water pressure outside the head 24. Thus, by filling the inside of the head 24 with high-pressure gas, for example, even when the housing 36 is damaged, it is possible to prevent water from entering the head 24.

  The controller 3 controls the operations of the laser oscillator 2, the head 24, the driving device 25, and the pressure regulator 11. The rotational speed of the upper portion of the head 24 including the mirror 34 is determined by using a sensor such as a resolver or a tachometer. Is feedback controlled. By this feedback control, the rotational speed of the head 24 is accurately controlled. Therefore, it is possible to accurately control the number of overlapping spots 46 of the pulse laser 45 in the cleaning target portion of the nozzle 23, and it is possible to reliably remove the clad without damaging the substrate.

  Further, when the rotation speed of the head 24 becomes a certain set value or less, the irradiation of the pulse laser 45 is stopped by the controller 3. With this function, it is possible to prevent the spot 46 from being excessively superimposed on the cleaning target portion of the nozzle 23, so that damage to the substrate due to laser irradiation can be avoided.

  In order to verify the effect of the method for cleaning a tubular member according to the present invention, a clad removal test was performed using a simulated test piece.

  FIG. 5 shows the result of the test for removing the clad on the stainless steel surface by the method for cleaning a tubular member of the present invention.

To a test piece in which about 7.4 g / cm ² of Fe ₂ O ₃ powder was attached as a simulated cladding on the surface of stainless steel (SUS316L), an Nd: YAG laser (wavelength: 1064 nm, pulse width: 100 ns (half width)), A 1.6 mm diameter spot 46 having a uniform intensity distribution (pulse repetition: 10 kHz) was scanned to evaluate the removal rate of Fe ₂ O ₃ . The test piece was irradiated with laser in an underwater atmosphere, and the underwater permeation distance 47 was 10 mm. The removal rate was evaluated by measuring the amount of Fe ₂ O ₃ deposited before and after laser irradiation by image processing, and a removal rate of 0.95 or higher was determined to be good.

As a result of the clad removal test, as is apparent from the graph of FIG. 5, when the pulse laser output is 0.34 J / cm ² , the removal rate is 95% or more when the number of spot overlaps is 500 or more. It was. Further, when the pulse laser output was 0.34 or more, it was found that the removal rate was good even at the spot superposition number of 400, and the clad on the stainless steel surface could be effectively removed.

  In addition, when the substrate was made of the same stainless cast steel as the nozzle 23, it was also evaluated by tests that the substrate was not sensitized and sounded under all laser irradiation conditions plotted on the graph.

Therefore, the energy density range of the pulse laser in the tubular member cleaning method of the present invention was set to 0.34 J / cm ^{2 to} 0.85 J / cm ² .

  FIG. 6 shows a removal test result when the underwater permeation distance 47 is 20 mm.

  In this test, a spot 46 having a diameter of 2.02 mm having a strong intensity distribution at the center and a weak intensity distribution at the periphery was scanned on the surface of the test piece. Other setting conditions and test methods were the same as those in the above-described test in which the permeation distance 47 in water was 10 mm.

As shown in FIG. 6, even when the underwater permeation distance 47 is set to 20 mm or less, the cladding can be satisfactorily removed at an energy density of 0.18 J / cm ² or more by setting the number of spot overlaps to about 1300. It turns out that it is possible to do.

  The Nd: YAG laser is absorbed by water when it passes through water, and the laser intensity attenuates exponentially. However, the attenuation of the laser intensity can be suppressed by setting the transmission distance to 20 mm or less. The clad can be efficiently removed.

  Therefore, based on these cladding removal tests, in the tubular member cleaning method of the present invention, when an Nd: YAG laser having a wavelength of 1064 nm is used as the pulse laser 45, the underwater transmission distance 47 of the pulse laser 45, that is, the window 35 is used. The distance to the inner surface of the nozzle 23 was set to 20 mm or less. More preferably, the underwater permeation distance of the pulse laser is 10 mm or less.

  As described above, according to the tubular member cleaning device of the present embodiment, the clad adhering to the inner surface of the nozzle 23 can be efficiently removed without damaging the substrate.

  Next, a tubular member cleaning apparatus according to a second embodiment for carrying out the tubular member cleaning method of the present invention will be described with reference to the drawings.

  The tubular member cleaning apparatus according to the second embodiment is a cleaning apparatus that removes the clad on the inner surface of the barrel section 19 or the flare section 21 of the inlet mixer 5. In addition, about the whole structure regarding installation of the cleaning apparatus of Example 2, and each component apparatus, about the structure similar to the cleaning apparatus of the tubular member of Example 1 mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  FIG. 7 shows an installation state of the head 24 in the tubular member cleaning apparatus of the second embodiment. FIG. 8 shows the internal structure of the head 24 in the tubular member cleaning apparatus of the second embodiment.

  The tubular member cleaning device according to the second embodiment includes a laser oscillator 2, an optical fiber cable 4, a head 24, a drive device 25, a controller 3, a gas cylinder 9, a pressure regulator 11, a connector 12, and a tube 13.

  In the tubular member cleaning apparatus according to the second embodiment, the head 24 shown in FIG. 8 includes a motor 29, a gear 30, and a bearing 31 as driving means, and a collimating lens 32, a condenser lens 33, and a mirror 34 as an optical processing system. And a window 35 and a slider 48 and a spring 49. These components are housed in a housing 36 and configured integrally. The casing 36 is waterproofed to prevent water from entering the casing 36.

  On the other hand, in the tubular member cleaning device according to the second embodiment, the drive device 25 includes a fixture 51, a wire 52, a lift drive unit 53, an air cylinder 54, an arm 55, and a roller 56, as shown in FIG. 7.

  Next, the operation of the tubular member cleaning apparatus according to the second embodiment will be described.

  The pulse laser 45 generated by the laser oscillator 2 is introduced into the optical fiber cable core 27 of the optical fiber cable 4 by the optical fiber cable incident unit built in the laser oscillator 2, and the inside of the optical fiber cable core 27 is introduced. The light is transmitted and emitted from the end face of the optical fiber cable core 27 in the head 24. The pulse laser 45 emitted from the end face is converted into quasi-parallel light by the collimating lens 32, reflected by the mirror 34, and emitted from the window 35 to the outside of the head 24 while being converged by the condenser lens 33. The pulse laser 45 emitted from the window 35 is allowed to pass through water and then irradiate the inner surface of the inlet mixer 5. The laser irradiation conditions in the present embodiment are the same as those in the tubular member cleaning apparatus of the first embodiment described above.

  Further, an Nd: YAG laser having a wavelength of 1064 nm is used as the pulse laser 45, and the underwater transmission distance 47 of the pulse laser 45, that is, the distance from the window 35 to the inner surface of the inlet mixer 5 is set to 20 mm or less.

  When the force caused by the internal pressure of the head 24 exceeds the force received from the spring 49, the head tip including the condenser lens 33 and the window 35 extends smoothly through the slider 48. This expansion / contraction mechanism adjusts the flare section 21 having a tapered shape so that the underwater permeation distance 38 is always 20 mm or less, and suppresses the spread of the spot 46 accompanying an increase in defocus, Compensate so that the energy density is an appropriate value.

  As shown in FIG. 7, an air cylinder 54 is integrally provided on the head 24 coaxially with the head 24, and the air cylinder 54 includes an arm 55 and a roller 56 attached to the tip of the arm 55. And are provided. When the tubular member cleaning device of this embodiment is used, the arm 55 is opened by the action of the air cylinder 54 in the flare section 21 of the inlet mixer 5, and the roller 56 at the tip of the arm 55 is pressed against the inner surface of the flare section 21. Thus, the head 24 is installed so as to be movable on the inner surface of the inlet mixer 5 in the tube axis direction. At this time, the arm 55 is accurately positioned so that the central axis of the head 24 and the central axis of the inlet mixer 5 coincide.

  The head 24 and the air cylinder 54 are suspended by a wire 52, and the wire 52 is suspended by an elevating drive unit 53 fixed to the bell mouth 18A by a fixing tool 51. The position of the head 24 in the tube axis direction is adjusted by winding the wire 52 with the lift drive unit 53 and moving the head 24 along the central axis of the inlet mixer 5. By this translational movement, the spot 46 of the pulse laser 45 is translationally scanned in the tube axis direction of the inlet mixer 5. Further, the rotational movement of the head 24 is adjusted by the same configuration as in the first embodiment.

  The spot 46 of the pulse laser 45 is scanned along the spiral path along the inner surface of the inlet mixer 5 by the combination of the translational motion and the rotational motion described above. By this scanning, the inner surface of the barrel section 19 or the flare section 21 of the inlet mixer 5 can be efficiently cleaned.

  The rotational speed of the upper part of the head 24 including the mirror 34 is feedback-controlled by the controller 3 using a sensor such as a resolver or a tachogen. The rotational speed is accurately controlled by the feedback control. Therefore, the number of superimposing spots 46 of the pulse laser 45 in the cleaning target portion can be accurately controlled. Therefore, the cladding can be sufficiently removed without damaging the substrate.

  In addition, when the rotational speed becomes a certain set value or less, the irradiation of the pulse laser 45 is stopped by a command from the controller 3. Therefore, excessive superposition of the spots 46 in the cleaning target portion can be prevented, and damage to the substrate due to laser irradiation can be avoided.

  In the tubular member cleaning apparatus of the second embodiment, the pressure of the high-pressure gas accumulated in the gas cylinder 9 is adjusted by the pressure regulator 11 and then the light is passed through the tube 13 and the connector 12 in the same manner as in the first embodiment. The inside of the head 24 is purged by introducing the gas into the protective tube 28 of the fiber cable 4. The gas pressure at this time is set higher than the water pressure outside the head 24 to prevent water from entering the head 24.

  As described above, according to the tubular member cleaning apparatus of this embodiment, it is possible to efficiently remove the clad adhering to the inner surface of the barrel section 19 or the flare section 21 without damaging the substrate. .

  Next, a modification of the tubular member cleaning apparatus of the second embodiment will be described.

  The tubular member cleaning device of this modification is obtained by changing the configuration of the head 24 in the cleaning device of the second embodiment described above. FIG. 9 shows an internal structure of the head 24 in the tubular member cleaning apparatus according to the modification.

  The head 24 of this modification includes a motor 29, a gear 30, and a bearing 31 as driving means, a collimating lens 32, a cylindrical lens 59, a mirror 34, and a window 35 as an optical processing system, and accommodates these components. And the housing 36. The cylindrical lens 59 is a lens that is curved in only one direction, and is installed so that the curved direction coincides with the horizontal direction (that is, the circumferential direction of the tube).

  In addition to the function of the tubular member cleaning device of the second embodiment, the tubular member cleaning device of this modification has the following functions.

  That is, the pulse laser 45 generated by the laser oscillator 2 is introduced into the head 24, converted into quasi-parallel light by the collimating lens 32, reflected by the mirror 34, and converged only in one direction by the cylindrical lens 59 while being focused on the window 35. To the outside of the head 24. The pulse laser 45 emitted from the window 35 is allowed to pass through the water and then irradiate the inner surface of the inlet mixer 5.

At this time, due to the action of the cylindrical lens 59, the spot 46 of the pulse laser 45 irradiated on the inner surface of the inlet mixer 5 becomes elliptical. The cylindrical lens 59 is installed so that the short tube axis direction of the ellipse coincides with the rotational scanning direction. The energy density on the laser irradiated surface is set to 0.34 J / cm ^{2 to} 0.85 J / cm ² . When an Nd: YAG laser having a wavelength of 1064 nm is used as the pulse laser 45, the underwater transmission distance 38 of the pulse laser 45, that is, the distance from the window 35 to the inner surface of the inlet mixer 5 is set to 20 mm or less. .

  According to the tubular member cleaning apparatus of this modification, the width of the spot 46 in the tube axis direction is increased, and therefore, the superposition of the spots 46 in the tube axis direction is facilitated, so that the cleaning efficiency is improved.

  In addition, in the tubular member cleaning device of this modification, the configuration in which the irradiation spot 46 of the pulse laser 45 is formed in an elliptical shape using one cylindrical lens 59 has been described, but a cylindrical lens array is used, Even when the irradiation spot 46 of the pulse laser 45 has a rectangular shape, the same operation and effect as described above can be obtained.

  Next, a method for attaching and detaching the tubular member cleaning apparatus according to the present invention to and from the inlet mixer will be described with reference to FIG.

  FIG. 10 shows a procedure for attaching / detaching the cleaning device to / from the inlet mixer 5.

  In the cleaning unit 1 of the tubular member cleaning device of the present invention, a joint 60 is provided at a joint portion between the driving device 25 and the head 24, and the head 24 and the driving device 25 are set at a constant angle by the joint 60. It is possible to adjust the bending.

  First, in order to insert the cleaning device into the inlet mixer 5, the head 24 is inserted from the secondary inlet opening 17A as shown in FIG. 10 (A), and the joint 60 of the driving device 25 as shown in FIG. 10 (B). And the head 24 is inserted into the inlet mixer 5. Next, the hook 41A of the holder 41 is fixed to the bell mouth 18A so that the center axis of the head 24 and the center axis of the nozzle 23 coincide with each other with reference to the positions of the bell mouth 18A, the rib 17B, and the inner surface of the barrel section 19. Thus, the head 24 is accurately positioned, and the head 24 is fixed to the throat section 18 as shown in FIG.

  10C, after the head 24 is driven by the driving device 25, the inner surface of the nozzle 23 is cleaned.

  After the nozzle 23 is cleaned, the tubular member cleaning device is attached to the inlet by a procedure reverse to the insertion of the head 24, that is, the procedure shown in FIGS. 10C, 10B, and 10A. Discharge outside the mixer 5.

  The tubular member cleaning method and cleaning device of the present invention are not limited to the cleaning of the inlet mixer as described above, and a cleaning method and a cleaning device for a tubular member immersed in water such as a constituent member of a nuclear reactor. Is generally applicable.

  As described above, according to the tubular member cleaning method and the cleaning device of the present invention, the nozzle 23 of the inlet mixer 5 and the inner surface of the inlet mixer 5 are disposed in a state where the inlet mixer 5 is installed at the operation position inside the nuclear reactor. Since cleaning can be performed, the time required for cleaning can be shortened, and the cost for cleaning can be reduced.

The whole block diagram of the cleaning device of the tubular member concerning the present invention. Sectional drawing which shows the installation state of the cleaning unit to an inlet mixer. The expanded sectional view which shows the structure of the installation part of an inlet mixer and a cleaning unit. FIG. 3 is a cross-sectional view illustrating the structure of the head portion of the tubular member cleaning device according to the first embodiment. The graph which shows the clad removal test result when the permeation distance in water is 10 mm. The graph which shows the clad removal test result when the permeation distance in water is 20 mm. FIG. 6 is a configuration diagram illustrating a state in which a cleaning head is installed in an inlet mixer according to a second embodiment. Sectional drawing which shows the structure of the head part of the cleaning apparatus of the tubular member which concerns on Example 2. FIG. Sectional drawing which shows the structure of the head part of the cleaning apparatus of the tubular member which concerns on the modification of Example 2. FIG. (A), (B) and (C) are the block diagrams which show the procedure which inserts the cleaning unit of the cleaning apparatus of the tubular member which concerns on this invention inside an inlet mixer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cleaning unit 2 Laser oscillator 3 Controller 4 Optical fiber cable 5 Inlet mixer 6 Power supply line 7 Signal line 8 Operating floor 9 Gas cylinder 11 Pressure regulator 12 Connector 13 Tube 15 Elbow 16 Pre-nozzle section 17 Nozzle section 17A 2nd inlet opening 17B Rib 18 Throat section 18A Bell mouth 19 Barrel section 21 Flare section 22 Sliding joint 23 Nozzle 24 Head 25 Drive device 27 Optical fiber cable core wire 28 Protective tube 29 Motor 30 Gear 31 Bearing 32 Collimating lens 33 Condensing lens 34 Mirror 35 Window 36 Housing 38 Motor 39 Ball screw 40 Cylinder portion 41 Holder 41A Hook 43, 44 Cable 45 Pulse laser 46 Spot 47 Underwater permeation distance 48 Slider 49 Spring 51 Fixing tool 52 Wire 53 Lifting drive unit 54 Air cylinder 55 Arm 56 Roller 59 Cylindrical lens 60 Joint

Claims (12)

A cleaning unit including a head for irradiating a pulse laser on the inner surface of a tubular member immersed in a liquid and a driving means for driving the head is inserted and fixed in the tubular member, and the head and light By oscillating a pulse laser by a laser oscillator connected by a fiber cable and supplying the pulse laser to the head, and operating the head and the driving means by a controller to scan the spot of the pulse laser on the inner surface of the tubular member A method for cleaning a tubular member, comprising removing the clad adhering to the tubular member. A cleaning unit having a head for irradiating a pulse laser to the inner surface of the inlet mixer as the tubular member installed in the boiling water reactor and a driving means for driving the head is inserted into the inlet mixer. The laser beam is oscillated by a laser oscillator connected to the head by an optical fiber cable to supply the pulse laser to the head, and the head and the driving means are operated by a controller to set the spot of the pulse laser to the inlet. 2. The method of cleaning a tubular member according to claim 1, wherein the clad adhering to the inlet mixer is removed by scanning the inner surface of the mixer. The pulse width of the pulse laser is set to 50 ns to 150 ns at a half width, and this pulse laser is irradiated to the surface of the tubular member in an underwater environment at an energy density of 0.34 J / cm ^{2 to} 0.85 J / cm ^2. The method for cleaning a tubular member according to claim 1. 2. The method for cleaning a tubular member according to claim 1, wherein the pulse laser is a pulse Nd: YAG laser, and the surface of the tubular member is irradiated with the pulse laser having a permeation distance of 20 mm or less. A motor is incorporated in the head, and the motor rotates the mirror in the direction of the rotation of the inlet mixer in the radial direction of the tube, and the head is connected to the tube by the driving device integrally attached to the head. 2. The method for cleaning a tubular member according to claim 1, wherein the inner surface of the inlet mixer is scanned along a spiral path in combination with translational scanning that translates in the axial direction. 6. The method for cleaning a tubular member according to claim 5, wherein an electric signal indicating the rotation speed of the mirror is output from the head, and the electric signal is input to the controller through a signal line. 6. The method for cleaning a tubular member according to claim 5, wherein when the rotation speed of the mirror in the head becomes equal to or lower than a set value, the irradiation of the pulse laser is stopped by a command from the controller. 6. The tubular member cleaning method according to claim 5, wherein a spot shape of the pulse laser is an ellipse or a rectangle, and a short tube axis direction of the spot coincides with a direction of the rotational scanning. The head portion provided with a laser irradiation window is driven in the tube diameter direction so as to match the tapered shape of the tubular member, and the underwater transmission distance and defocus of the pulse laser are adjusted. The method for cleaning a tubular member according to claim 1. The head is inserted into the inlet mixer from a secondary inlet opening of the inlet mixer and installed at a predetermined position, a pulse laser is supplied to the head by the optical fiber cable, and the head is operated by the controller. 3. The method for cleaning a tubular member according to claim 2, wherein after the pulse laser spot is scanned on the inner surface of the inlet mixer, the head is discharged from the secondary inlet opening to the outside of the inlet mixer. A joint that can bend the head and the drive device with the joint as a fulcrum is provided at the joint between the head and the drive device, and the cleaning unit is inserted by bending the joint when inserted into the inlet mixer. The method for cleaning a tubular member according to claim 2, wherein: A cleaning unit provided on the inner surface of a tubular member immersed in a liquid and emitting a pulse laser and a driving means for driving the head, a laser oscillator for oscillating the pulse laser, and the laser oscillator And a controller for operating the head and the driving means, and scanning the spot of the pulse laser on the inner surface of the tubular member A tubular member cleaning device, characterized by removing a clad.

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