JP7664200B2 - Lower component removal device and method of using the lower component removal device - Google Patents

Description

The present invention relates to a lower component removal device, which is a device for removing and attaching a lower component consisting of a spool piece, a motor bracket, and a motor unit located at the bottom of the control rod drive mechanism body, and a method for using the lower component removal device.

In recent years, advanced boiling water reactors (ABWRs) have adopted an electrically driven fine motion control rod drive mechanism (FMCRD), which is equipped with a control rod drive mechanism body, a motor unit, a motor bracket, and a spool piece and enables fine control rod drive.

This improved control rod drive mechanism is removed from the bottom of the reactor pressure vessel for maintenance and inspection during regular reactor inspections, and then reattached to the bottom of the reactor pressure vessel. The removal and installation of this improved control rod drive mechanism is carried out in an area with high levels of radiation, so it must be completed in a short period of time.

In response to this, Patent Document 1 discloses that an auxiliary handling cart is provided as a small attachment/detachment device in addition to the large attachment/detachment device (replacement machine) for the control rod drive mechanism main body (hereinafter referred to as the drive mechanism main body), and that the attachment and detachment of the motor unit and motor bracket, which are components that make up the control rod drive mechanism and are located below the drive mechanism main body (hereinafter referred to as the lower components), are performed on the auxiliary handling cart, thereby shortening the attachment/detachment work time.

JP 2000-329892 A

The lower components of the control rod drive mechanism may include the motor unit and motor bracket, as well as a spool piece that is connected to the drive mechanism body. However, in Patent Document 1, the spool piece that is connected to the drive mechanism body is detached using an attachment/detachment device (replacement machine) for the drive mechanism body, as in the past (paragraph 0073). In other words, in Patent Document 1, complex procedures must be followed to detach the spool piece, leaving room for improvement in reducing the work time.

The object of the present invention is to provide a lower component removal device that can remove and attach not only the motor unit and motor bracket but also the spool piece, further shortening the time required to remove and attach the control rod drive mechanism.

In order to achieve the above object, the present invention provides a lower component detachment device for attaching and detaching a lower component consisting of the spool piece, the motor bracket, and the motor unit from a reactor pressure vessel, among the components of a control rod drive mechanism that includes a control rod drive mechanism main body, a spool piece, a motor bracket, and a motor unit and drives a control rod, comprising: a first jig that holds a first component that is any one of the lower components; a second jig that holds a second component that is any one of the lower components and is detachable from the first jig; a third jig that holds a third component that is any one of the lower components and is detachable from the first jig; and a support section that supports the first jig so that it can be raised and lowered, and that can raise at least one of the first jig, the second jig, and the third jig to a height at which the spool piece can be detached.

According to the present invention, the spool piece can be attached and detached without using an attachment/detachment device for the drive mechanism body, further shortening the time required for attaching and detaching the control rod drive mechanism. Problems, configurations, and effects other than those described above will become clear from the description of the embodiments below.

1 is a schematic side view showing a state in which a lower component is detached from a control rod drive mechanism by a lower component detachment device according to a first embodiment of the present invention. FIG. FIG. 2 is an exploded view of the lower components of the control rod drive mechanism. FIG. FIG. 1 is a schematic side view of a lower component installation/removal device according to a first embodiment of the present invention, which supports a lower component at a high position. 1 is a schematic side view of a lower component installation/removal device according to a first embodiment of the present invention, which supports a lower component downward. FIG. 2 is a perspective view of a motor unit, a first jig that holds the motor unit, and a support portion that supports the first jig. FIG. 1 is a perspective view of a motor bracket, a second jig that holds the motor bracket and is detachable from the first jig, and a support portion that supports the first jig. FIG. 13 is a perspective view of a spool piece, a third jig that holds the spool piece and is detachable from the first jig, and a support portion that supports the first jig. FIG. 11 is a schematic side view of a lower component installation/removal device according to a second embodiment of the present invention, which supports a lower component at a high position. FIG. FIG. 11 is a schematic side view showing a state in which a lower component is detached from a control rod drive mechanism by a lower component detachment device according to a third embodiment of the present invention. FIG. 11 is a schematic side view showing a state in which a lower component is detached from a control rod drive mechanism by a lower component detachment device according to a fourth embodiment of the present invention.

The configuration and operation of the lower component installation and removal device according to the first to fourth embodiments of the present invention will be explained below with reference to the drawings.

First Embodiment
FIG. 1 is a schematic side view showing a state in which a lower component is being detached from a control rod drive mechanism by a lower component detachment device according to a first embodiment of the present invention.

The lower component removal device 1 is a device for removing and installing the lower component 32 of the control rod drive mechanism 3 provided at the bottom of the reactor pressure vessel 2 as shown in FIG. 1, and will be described in detail later.

The reactor pressure vessel 2 is a cylindrical steel structure that houses the fuel assemblies, and is installed on a cylindrical pedestal space 5 surrounded by a pedestal 4 inside the reactor containment vessel of an advanced boiling water reactor, for example. At the bottom of the reactor pressure vessel 2, multiple housings 21 protrude downward.

The control rod drive mechanism 3 is a device that controls nuclear fission by moving the control rod, located in the center of the fuel assembly, in and out of the reactor core. Normally, the control rod is moved in and out of the reactor core by the power of the motor unit 32c described below, and in the event of an abnormality, the control rod is inserted in one go into the reactor core by water pressure. The control rod drive mechanism 3 comprises a drive mechanism main body 31 and a lower component 32.

The drive mechanism body 31 is a component that grips and moves the control rod and is housed within the housing 21, and the lower end of the drive mechanism body 31 is flange-fastened to the lower part of the housing 21.

The lower component 32 is a plurality of components provided below the drive mechanism body 31. FIG. 2 is an exploded view of the lower component 32 of the control rod drive mechanism 3. As shown in FIG. 2, the lower component 32 includes a spool piece 32a, a motor bracket 32b, and a motor unit 32c.

Figure 3 is a perspective view of the spool piece 32a. The spool piece 32a is a component that transmits the rotational force generated by the motor unit 32c to the drive mechanism body 31. A flange portion 32aa is provided at the upper end of the spool piece 32a, and multiple through holes 32ab that penetrate vertically are provided in the flange portion 32aa.

Connecting parts (preferably bolts) are inserted into the multiple through holes 32ab from below and screwed into bolt holes (not shown) at the bottom of the drive mechanism body 31. This connects the spool piece 32a to the drive mechanism body 31.

The motor bracket 32b is a cylindrical component that connects the spool piece 32a and the motor unit 32c, and has a through hole (not shown) in the center for inserting the shaft 32ca protruding from the motor unit 32c. As shown in FIG. 2, the main body 32ba of the motor bracket 32b has multiple through holes 32bb that penetrate vertically.

Connecting parts (preferably bolts) are inserted from below into the multiple through holes 32bb and screwed into the bolt holes 32ac provided on the underside of the spool piece 32a. This connects the motor bracket 32b to the spool piece 32a.

Figure 4 is a perspective view of the motor unit 32c. The motor unit 32c is a component that has an electric motor inside as a drive source, and as shown in Figure 4, the output shaft 32ca protrudes from the upper end surface. A flange portion 32cb is provided on the upper portion of the motor unit 32c, and a plurality of through holes 32cc are provided in the flange portion 32cb that penetrate vertically.

Connecting parts (preferably bolts) are inserted from below into the multiple through holes 32cc and screwed into bolt holes 32bd (see FIG. 2) provided on the underside of the flange portion 32bc of the motor bracket 32b. This connects the motor unit 32c to the motor bracket 32b.

As shown in FIG. 1, the lower component removal device 1 is disposed on rails 7 laid on a platform 6 that is provided below the reactor pressure vessel 2 in the pedestal space 5 and can be rotated around the vertical direction by remote control. The lower component removal device 1 includes a holding jig 11 (first jig 11a, second jig 11b, and third jig 11c) that holds the lower component 32, and a support part 12.

Figure 5 is a schematic side view of the lower component detachment device 1 according to this embodiment, which supports the lower component 32 (spool piece 32a) at a high position. Figure 6 is a schematic side view of the lower component detachment device 1 according to this embodiment, which supports the lower component 32 (spool piece 32a) at a low position.

Figure 7 is a perspective view of the motor unit 32c, a first jig 11a that holds the motor unit 32c, and a support section 12 that supports the first jig. Figure 8 is a perspective view of the motor bracket 32b, a second jig 11b that holds the motor bracket 32b and is detachable from the first jig 11a, and a support section 12 that supports the first jig 11a. Figure 9 is a perspective view of the spool piece 32a, a third jig 11c that holds the spool piece 32a and is detachable from the first jig 11a, and a support section 12 that supports the first jig 11a.

The lower component installation/removal device 1 includes a holding jig 11 that holds one of the lower components 32, and a support portion 12 that supports the holding jig 11. The holding jig 11 also includes a first jig 11a, a second jig 11b, and a third jig 11c.

The first jig 11a is a holding jig 11 that holds one of the lower components 32 (the motor unit 32c in this embodiment). As shown in FIG. 7, the first jig 11a holds the motor unit 32c inserted into a central through-hole (not shown) of a disk-shaped member by using the upper surface of the flange portion 32cb provided on the upper side of the motor unit 32c.

The upper surface of the first jig 11a preferably has a plurality of pins (not shown) that are inserted into a plurality of through holes 32cc (e.g., a plurality of through holes 32cc excluding the two diagonal through holes 32cc) provided in the flange portion 32cb of the motor unit 32c.

The first jig 11a is preferably provided with two protrusions 11aa that protrude from the outer peripheral surface of the disk in the outward radial direction, symmetrically arranged on either side of a central through hole. The upper ends of two multi-stage cylinders 12a that form the support section 12 (described later) are connected to the lower surfaces of the two protrusions 11aa.

The second jig 11b is a holding jig 11 that holds one of the lower components 32 (the motor bracket 32b in this embodiment). As shown in FIG. 8, the second jig 11b is a disk, and the upper surface of the second jig 11b is preferably provided with two fan-shaped protrusions 11ba that protrude upward along the outer periphery, and a plurality of pins (not shown) that are inserted into a plurality of through holes 32bb, excluding, for example, the two diagonally arranged through holes 32bb, out of a plurality of through holes 32bb provided in the main body 32ba of the motor bracket 32b.

In addition, the second jig 11b is detachable from the first jig 11a, and preferably has a number of through holes (not shown) for inserting a number of pins (not shown) provided on the upper surface of the first jig 11a.

The motor bracket 32b has multiple pins (not shown) provided on the upper surface of the second jig 11b inserted into multiple through holes 32bb, except for the two diagonally arranged through holes 32bb, and is held in place by the upper surface of the second jig 11b and the two sector-shaped protrusions 11ba.

The third jig 11c is a holding jig 11 that holds one of the lower components 32 (the spool piece 32a in this embodiment) and is detachable from the first jig 11a. As shown in FIG. 9, the third jig 11c is a disk-shaped member, and preferably includes a central circular hole 11ca, two fan-shaped tool insertion holes 11cb that are symmetrically arranged on either side of the circular hole 11ca and communicate with the circular hole 11ca, a number of pins 11cc that protrude upward from the upper surface around the circular hole 11ca, and a number of through holes (not shown) for inserting a number of pins (not shown) provided on the upper surface of the first jig 11a.

The spool piece 32a is inserted into the central circular hole 11ca. The two tool insertion holes 11cb are through holes for inserting tools to attach and detach multiple connecting parts (two diagonally in this embodiment) that connect the spool piece 32a to the drive mechanism main body 31 while holding the spool piece 32a.

It is preferable that the tips of the multiple pins 11cc are inserted into multiple through holes 32ab provided in the flange portion 32aa of the spool piece 32a, excluding, for example, two diagonally arranged through holes 32ab.

The pins 11cc are provided with a flange-shaped protrusion 11cd (see Figs. 5, 6, and 9) at approximately the center in the vertical direction. The protrusion 11cd abuts against the underside of the flange 32aa at the upper end of the spool piece 32a inserted into the central circular hole 11ca, thereby supporting the spool piece 32a.

Due to these configurations of the third jig 11c, the spool piece 32a is held by the third jig 11c.

It is preferable that the width of each of the first jig 11a, the second jig 11b, and the third jig 11c is smaller than the distance between two adjacent control rod drive mechanisms 3 among the multiple control rod drive mechanisms 3 provided in the lower part of the reactor pressure vessel 2.

The support portion 12 is a component that supports the first jig 11a so that it can be raised and lowered, and can raise at least one of the first jig 11a, the second jig 11b, and the third jig 11c (the third jig 11c in this embodiment) to a height at which the highest spool piece 32a of the lower components 32 can be detached (the connection portion between the drive mechanism main body 31 and the spool piece 32a).

As shown in Figs. 5 and 6, the support section 12 preferably includes, for example, multiple (two in this embodiment) multi-stage cylinders 12a in which multiple overlapping tubes extend and contract vertically. The multiple multi-stage cylinders 12a preferably extend and contract using air pressure. The lower component installation/removal device 1 preferably includes an operating device (not shown) for operating the raising and lowering of the support section 12.

In addition, as shown in Figures 1, 5, and 6, the lower component removal device 1 preferably includes a moving part 13 that allows the support part 12 to move freely on the platform 6 below the reactor pressure vessel 2.

As shown in Figs. 5 and 6, the moving unit 13 preferably includes a carriage 13a having flanged wheels 13aa that can be moved manually along rails 7 laid on the platform 6, and a gripping portion 13ac that allows an operator to move the lower component installation/removal device 1. In addition, the carriage 13a is preferably provided with a stopper 13ab that fixes the carriage 13a that has been moved below the lower component 32.

Moreover, it is preferable that the moving unit 13 is provided with at least one of a slide table 13b that can move and position the support unit 12 along a predetermined plane, and a rotation table 13c that can rotate the support unit 12 around the vertical direction and can position the rotation angle. Note that the slide table 13b in this embodiment allows the support unit 12 to move along the plane on which the slide table 13b of the dolly 13a is placed.

In this embodiment, the slide table 13b is fixed onto the cart 13a, the rotating table 13c is fixed onto the slide table 13b, and the lower end of the support portion 12 is fixed onto the rotating table 13c.

In addition, it is preferable that the slide table 13b has a stopper (not shown) for positioning the slid table, and it is preferable that the rotation table 13c has a stopper (not shown) for positioning the rotation angle of the rotated table.

Next, we will explain how to use the lower component installation and removal device 1 according to this embodiment.

First, we will explain how to use the lower component removal device 1 when removing the lower component 32 from the reactor pressure vessel 2.

First, the platform 6 is rotated by remote control so that the rail 7 laid on the platform 6 passes under the motor unit 32c to be removed.

Next, the gripper 13ac attached to the trolley 13a is manually pushed along the rail 7 to directly below the motor unit 32c that removes the lower component installation/removal device 1, and the trolley 13a is fixed in place by the stopper 13ab.

Next, of the multiple bolts connecting the motor unit 32c to the motor bracket 32b, all but the two diagonally arranged bolts are removed using a tool (e.g., a long hexagonal deep socket).

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to stretch the support portion 12, and the motor unit 32c is held by the first jig 11a.

At this time, the motor unit 32c is inserted into the central circular hole (not shown) of the first jig 11a without interfering with the surrounding control rod drive mechanism 3, and multiple pins provided on the upper surface of the first jig 11a are inserted into the through hole 32cc of the motor unit 32c from which the multiple bolts connecting the motor unit 32c to the motor bracket 32b have been removed, and the position and orientation of the support part 12 are finely adjusted by the slide table 13b and the rotary table 13c so that the two bolts connecting the motor unit 32c to the motor bracket 32b can be removed from the tool insertion hole (not shown) of the first jig 11a.

The motor unit 32c is inserted into the circular hole in the center of the first jig 11a, multiple pins on the top surface of the first jig 11a are inserted into the through holes 32cc of the motor unit 32c, the flange portion 32cb abuts against the surface of the first jig 11a, and after it is confirmed that the motor unit 32c is held in place, the extension of the support portion 12 is stopped and the height of the first jig 11a is fixed.

Next, a tool is inserted into the tool insertion hole of the first jig 11a to remove the two bolts connecting the motor unit 32c to the motor bracket 32b, and then the motor unit 32c is removed from the reactor pressure vessel 2.

Next, the support 12 is retracted to lower the motor unit 32c. The platform 6 is then rotated by remote control, the lower component detachment device 1 is moved along the rails 7 to the repair room 8 (see FIG. 1) where maintenance and inspection of the lower component 32 is performed, and the motor unit 32c is lowered from the lower component detachment device 1.

Next, the lower component installation/removal device 1 is returned to the rail 7 on the platform 6, and the platform 6 is rotated by remote control so that the rail 7 passes under the motor bracket 32b to be removed.

Next, the lower component installation/removal device 1 is manually moved along the rail 7 to directly below the motor bracket 32b to be removed, and the cart 13a is fixed in place by the stopper 13ab.

Next, remove all of the bolts connecting the motor bracket 32b to the spool piece 32a, except for the two diagonally arranged bolts, using a tool (e.g., a long hexagonal deep socket).

Next, the second jig 11b is attached to the first jig 11a by inserting multiple pins on the top surface of the first jig 11a into multiple through holes in the second jig 11b.

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to stretch the support portion 12, and the motor bracket 32b is held by the second jig 11b.

At this time, the flange portion 32bc of the motor bracket 32b is inserted between the two sector-shaped protrusions 11ba of the second jig 11b without interfering with the surrounding control rod drive mechanism 3 between the first jig 11a and the second jig 11b, and multiple pins (not shown) provided on the upper surface of the second jig 11b are inserted into the through-hole 32bb of the motor bracket 32b after removing the multiple bolts connecting the motor bracket 32b to the spool piece 32a. The position and orientation of the support portion 12 are finely adjusted by the slide table 13b and the rotary table 13c so that the two bolts connecting the motor bracket 32b to the spool piece 32a can be removed from the tool insertion hole (not shown) of the second jig 11b.

The flange portion 32bc of the motor bracket 32b is inserted between the two sector-shaped protrusions 11ba of the second jig 11b, the multiple pins on the upper surface of the second jig 11b are inserted into the through holes 32bb of the motor bracket 32b, the lower surface of the flange portion 32bc abuts against the surface of the second jig 11b, and after it is confirmed that the motor bracket 32b is held by the second jig 11b, the extension of the support portion 12 is stopped and the height of the second jig 11b is fixed.

Next, insert a tool into the tool insertion hole of the second jig 11b to remove the two bolts connecting the motor bracket 32b to the spool piece 32a, and then remove it from the reactor pressure vessel 2.

Next, the support 12 is retracted to lower the motor bracket 32b. The platform 6 is then rotated by remote control, the lower component installation/removal device 1 is moved along the rails 7 to a repair room where maintenance and inspection of the lower component 32 is performed, and the motor bracket 32b is lowered from the lower component installation/removal device 1.

Next, the lower component installation/removal device 1 is returned to the rail 7 on the platform 6, and the platform 6 is rotated by remote control so that the rail 7 passes under the spool piece 32a to be removed.

Next, the lower component installation/removal device 1 is manually moved along the rail 7 to directly below the spool piece 32a to be removed, and the trolley 13a is fixed in place by the stopper 13ab.

Next, of the multiple bolts connecting the spool piece 32a to the drive mechanism body 31, all but the two diagonally arranged bolts are removed using a tool (e.g., a long hexagonal deep socket).

Next, the second jig 11b is removed from the first jig 11a, and then the third jig 11c is attached to the first jig 11a by inserting multiple pins on the top surface of the first jig 11a into multiple through holes in the third jig 11c.

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to stretch the support portion 12, and the spool piece 32a is held by the third jig 11c.

At this time, the spool piece 32a is inserted into the central circular hole 11ca of the third jig 11c without interfering with the surrounding control rod drive mechanism 3 between the first jig 11a and the third jig 11c, and after removing the bolts connecting the spool piece 32a to the drive mechanism body 31, the pins 11cc (see FIG. 9) provided on the upper surface of the third jig 11c are inserted into the through holes 32ab of the spool piece 32a, and the position and orientation of the support part 12 are finely adjusted by the slide table 13b and the rotary table 13c so that the two bolts connecting the spool piece 32a to the drive mechanism body 31 can be removed from the tool insertion holes 11cb (see FIG. 9) of the third jig 11c.

The spool piece 32a is inserted into the circular hole 11ca in the center of the third jig 11c, the multiple pins 11cc on the top surface of the third jig 11c are inserted into the through holes 32ab of the spool piece 32a, the bottom surface of the flange portion 32aa abuts against the upper ends of the protrusions 11cd on the multiple pins 11cc of the third jig 11c, and after it is confirmed that the spool piece 32a is held by the third jig 11c, the extension of the support portion 12 is stopped and the height of the third jig 11c is fixed.

Next, a tool is inserted into the tool insertion hole 11cb of the third jig 11c to remove the two bolts that connect the spool piece 32a to the drive mechanism body 31, and then the spool piece 32a is removed from the reactor pressure vessel 2.

Next, the support 12 is retracted to lower the spool piece 32a. The platform 6 is then rotated by remote control, the lower component installation/removal device 1 is moved along the rails 7 to the repair room 8, and the spool piece 32a is lowered from the lower component installation/removal device 1 into the repair room.

By using the above-described method of using the lower component removal device 1, each of the lower components 32 is removed from the reactor pressure vessel 2.

Next, we will explain how to use the lower component removal device 1 when installing the lower component 32 to the reactor pressure vessel 2.

First, the through holes 32ab of the spool piece 32a that has been inspected and maintained in the repair room are inserted into multiple pins 11cc provided on the upper surface of the third jig 11c that is attached to the first jig 11a at the upper end of the contracted support part 12 of the lower component installation/removal device 1, and the spool piece 32a is held by the third jig 11c.

Next, the lower component installation/removal device 1 is returned to the rail 7 on the platform 6, and the platform 6 is rotated by remote control so that the rail 7 passes under the drive mechanism body 31 to which the spool piece 32a is attached.

Next, the lower component installation/removal device 1 is manually moved along the rail 7 directly below the drive mechanism body 31 to which the spool piece 32a is attached, and the cart 13a is fixed by the stopper 13ab.

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to extend the support portion 12 and raise the spool piece 32a to the bottom end of the drive mechanism body 31.

At this time, the spool piece 32a is raised to the lower end of the drive mechanism body 31 without interfering with the surrounding control rod drive mechanism 3 by the first jig 11a and the third jig 11c, and the position and orientation of the support part 12 are finely adjusted by the slide table 13b and the rotary table 13c so that two bolts can be attached from the tool insertion hole 11cb of the third jig 11c (see FIG. 9) through the through holes 32ab that penetrate vertically in the flange part 32aa of the spool piece 32a to two diagonal bolt holes (not shown) on the underside of the drive mechanism body 31.

Next, two bolts are screwed from the tool insertion hole 11cb of the third jig 11c through the through holes 32ab of the spool piece 32a into two diagonal bolt holes on the underside of the drive mechanism body 31, connecting the spool piece 32a to the drive mechanism body 31.

Next, the support 12 is contracted, the third jig 11c is lowered, and the bolts are screwed into the remaining bolt holes on the underside of the drive mechanism body 31 through the through holes 32ab of the spool piece 32a, connecting the spool piece 32a to the drive mechanism body 31.

Next, the platform 6 is rotated by remote control, and the lower component installation/removal device 1 is moved along the rails 7 to the repair room 8.

Next, the third jig 11c is removed from the first jig 11a, and then the second jig 11b is attached to the first jig 11a by inserting multiple pins on the top surface of the first jig 11a into multiple through holes in the second jig 11b.

Next, the through holes 32bb of the motor bracket 32b that has been inspected and maintained are inserted into multiple pins (not shown) provided on the upper surface of the second jig 11b, and the motor bracket 32b is held by the second jig 11b.

Next, the lower component installation/removal device 1 is returned to the rail 7 on the platform 6, and the platform 6 is rotated by remote control so that the rail 7 passes under the spool piece 32a to which the motor bracket 32b is attached.

Next, the lower component installation/removal device 1 is manually moved along the rail 7 to directly below the spool piece 32a to which the motor bracket 32b is attached, and the trolley 13a is fixed in place by the stopper 13ab.

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to extend the support portion 12 and raise the motor bracket 32b to the bottom end of the spool piece 32a.

At this time, the motor bracket 32b is raised to the lower end of the spool piece 32a without interfering with the surrounding control rod drive mechanism 3 between the first jig 11a and the second jig 11b, and multiple pins (not shown) provided on the upper surface of the second jig 11b are inserted into the through holes 32bb of the motor bracket 32b after removing the multiple bolts connecting the motor bracket 32b to the spool piece 32a. The position and orientation of the support 12 are finely adjusted by the slide table 13b and the rotary table 13c so that two bolts are attached from the tool insertion hole (not shown) of the second jig 11b through the through holes 32bb that penetrate vertically in the main body 32ba of the motor bracket 32b to two diagonal bolt holes 32ac (see FIG. 2) provided on the lower surface of the spool piece 32a.

Next, after removing the multiple bolts that connect the motor bracket 32b to the spool piece 32a, multiple pins (not shown) provided on the upper surface of the second jig 11b are inserted into the through holes 32bb of the motor bracket 32b.

Next, two bolts are screwed from the tool insertion holes of the second jig 11b through the through holes 32bb provided in the body 32ba of the motor bracket 32b into two diagonal bolt holes 32ac on the underside of the spool piece 32a, connecting the motor bracket 32b to the spool piece 32a.

Next, the support portion 12 is contracted, the second jig 11b is lowered, and the bolts are screwed into the remaining bolt holes 32ac on the underside of the spool piece 32a through the through holes 32bb in the motor bracket 32b, thereby connecting the motor bracket 32b to the spool piece 32a.

Next, the platform 6 is rotated by remote control, and the lower component installation/removal device 1 is moved along the rails 7 to the repair room. In the repair room, the second jig 11b attached to the first jig 11a at the upper end of the contracted support part 12 is removed.

Next, the through-hole 32cc (see FIG. 4) of the motor unit 32c that has been inspected and maintained is inserted into multiple pins (not shown) provided on the upper surface of the first jig 11a, and the motor unit 32c is held by the first jig 11a.

Next, the lower component installation/removal device 1 is returned to the rail 7 on the platform 6, and the platform 6 is rotated by remote control so that the rail 7 passes under the motor bracket 32b on which the motor unit 32c is attached.

Next, the lower component installation/removal device 1 is manually moved along the rail 7 to directly below the motor bracket 32b to which the motor unit 32c is attached, and the dolly 13a is fixed by the stopper 13ab.

Next, compressed air is injected into the support portion 12 using the operating device provided on the lower component installation/removal device 1 to extend the support portion 12 and raise the motor unit 32c to the lower end of the motor bracket 32b.

At this time, the motor unit 32c is raised to the lower end of the motor bracket 32b without interfering with the surrounding control rod drive mechanism 3 by the first jig 11a, and multiple pins provided on the upper surface of the first jig 11a are inserted into the through holes 32cc of the motor unit 32c from which the multiple bolts connecting the motor unit 32c to the motor bracket 32b have been removed. The position and orientation of the support part 12 are finely adjusted by the slide table 13b and the rotary table 13c so that two bolts are attached from the tool insertion hole (not shown) of the first jig 11a through the through holes 32cc that penetrate vertically in the flange part 32cb of the motor unit 32c to two diagonal bolt holes 32bd (see Figure 2) among the bolt holes 32bd provided on the lower surface of the flange part 32bc of the motor bracket 32b.

Next, multiple pins provided on the top surface of the first jig 11a are inserted into the through holes 32cc of the motor unit 32c from which the multiple bolts connecting the motor unit 32c to the motor bracket 32b have been removed.

Next, two bolts are screwed from the two tool insertion holes of the first jig 11a through the diagonal through holes 32cc of the multiple through holes 32cc provided in the flange portion 32cb (see FIG. 7) of the motor unit 32c into two diagonal bolt holes 32bd (see FIG. 2) of the bolt holes 32bd provided in the underside of the flange portion 32bc of the motor bracket 32b, thereby connecting the motor unit 32c to the motor bracket 32b.

Then, the support portion 12 is contracted to lower the first jig 11a, and bolts are screwed into the remaining bolt holes 32bd on the underside of the motor bracket 32b through the through holes 32cc of the motor unit 32c, thereby connecting the motor unit 32c to the motor bracket 32b.

By using the above-described method of using the lower component removal device 1, each of the lower components 32 is attached to the reactor pressure vessel 2.

(Action and Effects)
The lower component removal and installation device 1 of this embodiment is for removing and installing a lower component 32 consisting of a spool piece 32a, a motor bracket 32b and a motor unit 32c from a reactor pressure vessel 2, among the components of a control rod drive mechanism 3 that includes a drive mechanism main body 31, a spool piece 32a, a motor bracket 32b and a motor unit 32c and drives a control rod, and includes a first jig 11a that holds a first component (motor unit 32c in this embodiment) that is one of the lower components 32, and a lower component removal and installation device 1 for removing and installing a lower component 32 consisting of a spool piece 32a, a motor bracket 32b and a motor unit 32c from a reactor pressure vessel 2. the second jig 11b holding a second component which is one of the lower components 32 (in this embodiment, the motor bracket 32b) and being detachable from the first jig 11a; a third jig 11c holding a third component which is one of the lower components 32 (in this embodiment, the spool piece 32a) and being detachable from the first jig 11a; and a support portion 12 supporting the first jig 11a so that it can be raised and lowered, and capable of raising at least one of the first jig 11a, the second jig 11b and the third jig 11c to a height at which the spool piece 32a can be detached (the height to the connection portion between the drive mechanism main body 31 and the spool piece 32a).

That is, the lower component removal and installation device 1 of this embodiment includes a holding jig 11 (first jig 11a, second jig 11b, and third jig 11c) that holds the motor unit 32c, motor bracket 32b, and spool piece 32a, and the holding jig 11 that holds the spool piece 32a can be raised and lowered to a height at which the spool piece 32a can be removed and installed. Therefore, not only the motor unit 32c and motor bracket 32b attached to the lower part of the drive mechanism main body 31 but also the spool piece 32a can be removed and installed, so that the spool piece 32a can be removed and installed without using the removal and installation device of the drive mechanism main body 31, and the installation and removal work time of the control rod drive mechanism 3 can be shortened.

In addition, in the lower component detachment device 1 of this embodiment, at least one of the first jig 11a, the second jig 11b, and the third jig 11c is provided with a tool insertion hole (e.g., tool insertion hole 11cb) for inserting a tool for attaching and detaching multiple connecting parts that connect the components included in the lower component 32 to the components 31 and 32 above it.

As a result, while the lower component 32 is held by the first jig 11a, the second jig 11b, and the third jig 11c, multiple connecting parts (e.g., bolts) that connect the components included in the lower component 32 to the components 31, 32 above it can be easily attached and detached, thereby shortening the time required for attaching and detaching the control rod drive mechanism 3. In addition, the portion where the first jig 11a, the second jig 11b, and the third jig 11c hold the lower component 32 can be made larger regardless of the position of the connecting parts, allowing the lower component 32 to be held stably.

In addition, at least one of the first jig 11a, the second jig 11b, and the third jig 11c of the lower component installation/removal device 1 of this embodiment is provided with multiple pins, and the component held by the holding jig 11 provided with the multiple pins of the lower component 32 is provided with multiple through holes 32ab, 32bb, and 32cc, and the multiple pins can be inserted into the multiple through holes 32ab, 32bb, and 32cc.

As a result, each of the first jig 11a, the second jig 11b, and the third jig 11c can position and hold one of the multiple lower components 32. Therefore, when attaching or detaching the multiple coupling parts that connect the lower component 32 to the upper components 31 and 32, it becomes easier to align the tool insertion hole (e.g., tool insertion hole 11cb) for inserting a tool provided in the holding jig 11, the multiple through holes 32ab, 32bb, and 32cc (see Figures 2 to 4) for inserting the coupling parts provided in the lower component, and the parts (e.g., bolt holes 32ac and 32bd) that connect the coupling parts provided in the upper components 31 and 32 that are connected to the lower component 32, thereby shortening the time required for attaching or detaching the control rod drive mechanism 3.

The lower component removal and installation device 1 of this embodiment is equipped with a moving part 13 that allows the support part 12 to move freely on the platform 6 below the reactor pressure vessel 2. Therefore, the lower component removal and installation device 1 can move freely on the platform 6 provided below the reactor pressure vessel 2 in the pedestal space 5, further shortening the time required for removing and installing multiple control rod drive mechanisms 3.

The moving part 13 of the lower component installation/removal device 1 of this embodiment is provided with at least one of a slide table 13b that can move the support part 12 along a predetermined plane, and a rotating table 13c that can rotate the support part 12 around a rotation axis centered on the vertical direction.

This allows the support 12 to slide and rotate so that the first jig 11a, the second jig 11b, and the third jig 11c do not interfere with the control rod drive mechanism 3. In addition, the position and orientation of the support 12 can be fine-tuned so that multiple pins (e.g., pin 11cc) provided on the upper surfaces of the first jig 11a, the second jig 11b, and the third jig 11c can be inserted into the through holes 32ab, 32bb, and 32cc (see Figures 2 to 4) of the lower component 32 after removing the multiple connecting parts (bolts) that connect the lower component 32 to the upper components 31 and 32. In addition, it is easy to align the through holes 32ab, 32bb, 32cc (see Figures 2 to 4) through which the connecting parts (e.g., bolts) provided on each of the lower components 32 pass, the parts that connect the connecting parts provided on the upper components (e.g., bolt holes 32ac, 32bd), and the tool insertion hole (e.g., tool insertion hole 11cb) for inserting a tool provided on the holding jig.

The support section 12 of the lower component installation/removal device 1 of this embodiment also includes multiple (two in this embodiment) multi-stage cylinders 12a, each of which is made up of multiple overlapping tubes that can expand and contract vertically.

The multi-stage cylinder 12a can obtain a large thrust with a small mounting area and can provide a long operating stroke with a short mounting length. This allows the mounting area of the support part 12 to be narrowed, and the holding jig 11 can be easily and quickly raised and lowered to a high position, further shortening the time required for attaching and detaching the multiple control rod drive mechanisms 3.

The multiple multi-stage cylinders 12a of the lower component installation/removal device 1 of this embodiment expand and contract using air pressure. This reduces the risk of damage to the multi-stage cylinders 12a due to water droplets falling from above. In addition, the pedestal space 5 is provided with a port for a service air system that supplies compressed air, and compressed air can be easily supplied to the multi-stage cylinders 12a by connecting to this port, which eliminates the need to install a new pressure supply source and reduces costs.

In the lower component installation/removal device 1 of this embodiment, the moving part 13 is provided with wheels 13aa and a grip part 13ac, and an operating device for operating the raising and lowering of the support part 12 is mounted on the lower component installation/removal device 1. Therefore, since the operation can be performed on the machine side without operating from a remote operation room, fine adjustment of the moving part 13 and the support part 12 can be easily performed, and the operation time can be shortened.

In the lower component removal and installation device 1 of this embodiment, the multiple connecting parts are bolts. Therefore, the multiple connecting parts can be manually installed and removed by an operator, so that even if multiple control rod drive mechanisms 3 are installed and the work space is narrow, the installation and removal of multiple lower components 32 can be easily performed.

In the lower component removal device 1 of this embodiment, the width of each of the first jig 11a, the second jig 11b, and the third jig 11c is smaller than the distance between two adjacent control rod drive mechanisms 3 among the multiple control rod drive mechanisms 3 provided in the lower part of the reactor pressure vessel 2.

Therefore, the holding jig 11 can be raised without interfering with the control rod drive mechanism 3 around the lower component 32 that is removed from the bottom of the reactor pressure vessel 2 for maintenance and inspection. Therefore, the lower component 32 can be safely detached.

In addition, the method of using the lower component detachment device 1 of this embodiment is a method of using the lower component detachment device 1 to detach a lower component 32 consisting of a spool piece 32a, a motor bracket 32b and a motor unit 32c from a reactor pressure vessel 2, among the components of the control rod drive mechanism 3 that includes a drive mechanism main body 31, a spool piece 32a, a motor bracket 32b and a motor unit 32c and drives a control rod, in which a plurality of through holes 32ab, 32bb, 32cc are provided in the component 32 to be detached for inserting a plurality of coupling parts that couple the component to be detached to the component above it, and the lower component detachment device 1 holds the component to be detached. The component 32 to be detached is provided with a holding jig 11 that holds the component 32 to be detached, and a support section 12 that supports the holding jig 11 so that it can be raised and lowered and can raise the holding jig 11 to a height at which the component 32 to be detached can be detached. When the component 32 to be detached is detached using the holding jig 11, coupling parts are inserted into two of the through holes 32ab, 32bb, 32cc that are diagonally positioned, and the coupling parts are removed from the remaining through holes 32ab, 32bb, 32cc. In this state, the component 32 to be detached is held by the holding jig 11, and the holding jig 11 that holds the component 32 to be detached is raised and lowered by the support section 12, and the coupling parts are removed or attached to the component 32 to be detached, thereby detaching the component 32 to be detached.

This allows multiple lower components 32 to be removed from the reactor pressure vessel by only removing two diagonally arranged connecting parts, thereby shortening the work time.

Furthermore, in the method of using the lower component detachment device 1 of this embodiment, when attaching or detaching the component 32 to be detached or attached using the holding jig 11, coupling parts are inserted into two of the through holes 32ab, 32bb, 32cc located diagonally out of the multiple through holes 32ab, 32bb, 32cc, and coupling parts are removed from the remaining through holes 32ab, 32bb, 32cc, and multiple pins (e.g., pin 11cc) provided on the upper surface of the holding jig 11 are inserted into the remaining through holes 32ab, 32bb, 32cc to hold the component 32 to be detached or attached with the multiple pins (e.g., pin 11cc), and the holding jig 11 holding the component 32 to be detached or attached is raised or lowered by the support part 12, and the coupling parts are removed or attached to the component 32 to be detached or attached, thereby detaching or attaching the component to be detached or attached.

This makes it easier to align the through hole (e.g., tool insertion hole 11cb) for inserting a tool provided in the holding jig 11, the through holes 32ab, 32bb, 32cc (see Figures 2 to 4) for inserting the coupling parts provided in the lower component, and the parts (e.g., bolt holes 32ac, 32bd) for connecting the coupling parts provided in the upper components 31, 32 that are connected to the lower component 32 when attaching or detaching the multiple coupling parts that connect the lower component 32 to the upper components 31, 32, thereby shortening the time required for attaching or detaching the control rod drive mechanism 3.

Second Embodiment
FIG. 10 is a schematic side view of a lower component installation/removal device 201 according to a second embodiment of the present invention, which supports the lower component 32 (spool piece 32a) at a high position.

The lower component installation/removal device 201 according to this embodiment differs from the lower component installation/removal device 1 according to the first embodiment in the moving part 213. That is, the moving part 13 of the lower component installation/removal device 1 according to the first embodiment has flanged wheels 13aa that can be moved manually along rails 7 laid on the platform 6, as shown in Figures 5 and 6. On the other hand, the moving part 213 of the lower component installation/removal device 201 according to this embodiment has swivel wheels 213aa that run on the platform 6.

(Action and Effects)
The moving section 213 of the lower component installation/removal device 201 according to this embodiment includes swivel wheels 213aa that run on the platform 6. This allows the lower component installation/removal device 201 to move freely on the platform 6, instead of on the rails 7 laid on the platform 6, eliminating the need to remotely rotate the platform 6, facilitating movement and shortening the movement time.

Third Embodiment
FIG. 11 is a schematic side view showing a state in which a lower component 32 is being detached from a reactor pressure vessel 2 by a lower component detachment device 301 according to the third embodiment of the present invention.

The lower component installation/removal device 301 according to this embodiment differs from the lower component installation/removal device 1 according to the first embodiment in that it is equipped with a transport cart 314.

The transport cart 314 is equipped with a platform for placing the lower component 32 and wheels, and is capable of transporting the lower component 32 removed from the reactor pressure vessel 2 to the repair room 8.

(Action and Effects)
The lower component removal device 301 according to this embodiment includes a transport cart 314 for transporting the lower component 32 removed from the reactor pressure vessel 2. This allows the lower component 32 removed from the reactor pressure vessel 2 to be easily and quickly transported to the repair room 8, and allows the lower component 32 that has been subjected to maintenance and inspection in the repair room 8 to be easily and quickly transported from the repair room 8. This allows the efficiency of the installation and removal work of the multiple control rod drive mechanisms 3 to be improved.

Fourth Embodiment
FIG. 12 is a schematic side view showing a state in which the lower component 32 is detached from the reactor pressure vessel 2 by the lower component detachment device 401 according to the fourth embodiment of the present invention.

The lower component installation/removal device 401 according to this embodiment differs from the lower component installation/removal device 1 according to the first embodiment in that a tilt absorbing portion 412b that absorbs the tilt of the first jig 11a is provided at the upper end of the multiple multi-stage cylinders 12a.

The tilt absorbing section 412b can be, for example, a suspension.

(Action and Effects)
In the lower component installation and removal device 401 of the present embodiment, tilt absorbing portions 412b that absorb the tilt of the first jig 11a are provided at the upper ends of the multiple multi-stage cylinders 12a. Therefore, when holding any one of the lower components 32, the first jig 11a, the second jig 11b, and the third jig 11c can be tilted along the contact surface of the lower component 32, so that the lower component 32 can be stably installed and removed.

The present invention is not limited to the above-described embodiments, but includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

The embodiment of the present invention may be in the following form. That is, the embodiment in which the first jig 11a holds the motor unit 32c, the second jig 11b holds the motor bracket 32b, and the third jig 11c holds the spool piece 32a has been shown, but is not limited to this. For example, the embodiment may be such that the second jig 11b holds the motor unit 32c, the third jig 11c holds the motor unit 32c, and the first jig 11a holds the spool piece 32a. Also, the embodiment may be such that the third jig 11c holds the motor unit 32c, the first jig 11a holds the motor unit 32c, and the second jig 11b holds the spool piece 32a.

1, 201, 301, 401...Lower component removal device, 2...Reactor pressure vessel, 3...Control rod drive mechanism, 4...Pedestal, 5...Pedestal space, 6...Platform, 7...Rail, 8...Repair room, 11...Holding jig, 11a...First jig, 11aa...Protrusion, 11b...Second jig, 11ba...Flange-shaped protrusion, 11c...Third jig, 11ca...Circular hole, 11cb...Tool insertion hole, 11cc...Pin, 11cd...Protrusion, 12...Support part, 12a...Multi-stage cylinder, 13...Moving part, 13a...Cart, 13aa...Flange-equipped wheel, 13ab...Strut 13ac...gripping part, 13b...slide table, 13c...rotating table, 21...housing, 31...driving mechanism main body, 32...lower component, 32a...spool piece, 32aa...flange part, 32ab...through hole, 32ac...bolt hole, 32b...motor bracket, 32ba...main body, 32bb...through hole, 32bc...flange part, 32bd...bolt hole, 32c...motor unit, 32ca...shaft, 32cb...flange part, 32cc...through hole, 213...moving part, 314...transport cart, 412b...tilt absorbing part

Claims (15)

A lower component removal device for removing a lower component, which is made up of a spool piece, a motor bracket, and a motor unit, from a reactor pressure vessel, of components of a control rod drive mechanism that drives a control rod and includes a control rod drive mechanism main body, a spool piece, a motor bracket, and a motor unit, the lower component comprising the spool piece, the motor bracket, and the motor unit,
A first jig that holds a first component that is any one of the lower components;
a second jig that holds a second component that is any one of the lower components and is detachably attached to the first jig;
a third jig that holds a third component that is any one of the lower components and is detachably attached to the first jig;
A support portion that supports the first jig so as to be able to rise and fall and that can raise at least one of the first jig, the second jig, and the third jig to a height at which the spool piece can be attached and detached;
A lower component removal device comprising: 2. The lower component removal device according to claim 1,
A lower component removal device characterized in that at least one of the first jig, the second jig, and the third jig is provided with a through hole for inserting a removal tool for multiple connecting parts that connect a component included in the lower component to a component above it. 2. The lower component removal device according to claim 1,
At least one of the first jig, the second jig, and the third jig is provided with a plurality of pins,
a component held by the jig having the plurality of pins among the lower components is provided with a plurality of through holes;
The plurality of pins are insertable into the plurality of through holes. 2. The lower component removal device according to claim 1,
a moving part for moving the support part freely on a platform below the reactor pressure vessel, The lower component removal device according to claim 4,
A lower component removal device characterized in that the moving section is provided with at least one of a slide table that can move the support section along a predetermined plane and a rotary table that can rotate the support section around the vertical direction. 2. The lower component removal device according to claim 1,
A lower component removal device characterized in that the support portion comprises a plurality of multi-stage cylinders having overlapping tubes that can be extended and contracted vertically. 7. The lower component removal device according to claim 6,
The lower component removal device is characterized in that the multiple multi-stage cylinders extend and retract by air pressure. The lower component removal device according to claim 4,
The moving part is provided with wheels and a grip part,
A lower component installation/removal device comprising an operating device for operating the raising and lowering of the support part. 3. The lower component removal device according to claim 2,
A lower component installation and removal device, wherein each of the plurality of connecting parts is a bolt. The lower component removal device according to claim 4,
A lower component installation/removal device, characterized in that the moving unit is equipped with swivel wheels that run on the platform. 2. The lower component removal device according to claim 1,
a lower component removal device including a transport cart for transporting the lower component removed from the reactor pressure vessel. 7. The lower component removal device according to claim 6,
a lower component installation/removal device, characterized in that an inclination absorbing portion that absorbs the inclination of the first jig is provided at the upper ends of the multiple multi-stage cylinders. 2. The lower component removal device according to claim 1,
a lateral width of each of the first jig, the second jig, and the third jig is smaller than a distance between two adjacent control rod drive mechanisms among a plurality of control rod drive mechanisms provided in the lower part of the reactor pressure vessel. A method for using a lower component removal device to remove a lower component, which is a component of a control rod drive mechanism including a control rod drive mechanism main body, a spool piece, a motor bracket, and a motor unit and drives a control rod, from a reactor pressure vessel, the method comprising:
a plurality of through holes for inserting a plurality of coupling parts for coupling the component to be detached among the lower components to the component above the component to be detached;
The lower component installation and removal device includes:
A jig for holding the component to be detached;
a support unit that supports the jig so that the jig can be raised and lowered and that can raise the jig to a height at which the component to be detached can be detached;
When the component to be detached is detached using the jig,
holding the component to be detached with the jig in a state in which the coupling parts are inserted into two diagonally opposite through holes among the plurality of through holes and the coupling parts are removed from the remaining through holes;
The jig that holds the component to be detached is raised and lowered by the support portion;
A method of using a lower component removal device, comprising the steps of: removing or attaching the coupling part to the component to be removed; and removing the component to be removed. 15. A method of using the lower component removal device according to claim 14, comprising:
When the component to be detached is detached using the jig,
the coupling components are inserted into two diagonally positioned through holes among the plurality of through holes, and the coupling components are removed from the remaining through holes, and a plurality of pins provided on an upper surface of the jig are inserted into the remaining through holes to hold the component to be detached with the plurality of pins;
The jig that holds the component to be detached is raised and lowered by the support portion;
A method of using a lower component removal device, comprising the steps of: removing or attaching the coupling part to the component to be removed; and removing the component to be removed.

Images