JPH0372435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that can automatically clean bolts contaminated with radioactivity and automatically attach and detach nuts.

The reactor pressure vessel is constructed by connecting the pressure vessel body and the upper mirror, which is a sealed head placed on the pressure vessel body, with stud bolts (hereinafter simply referred to as "bolts"), and sealing the pressure vessel body. It is configured.

FIG. 1 shows the details of the connection state using bolts, and the bolt 13 is connected to the pressure vessel body 32 by a threaded portion 13a which is threadedly engaged with a female threaded portion 32a' formed on the flange 32a of the body 32, and protrudes from the upper surface thereof. On the other hand, the threaded portion 13b at the other end projects outside the flange 1a by passing through an insertion hole 1a' formed in the flange 1a of the upper mirror 1 and having a diameter larger than the outer diameter of the threaded portion 13b. A nut 15 is screwed into this threaded portion 13b, and the tightening force of the nut 15 firmly connects the upper mirror 1 and the main body 32 with the bolt 13. These bolts 13 are placed close to each other in the circumferential direction of the upper mirror 1 and the main body 32 to the extent that the nuts 15 almost touch each other, and a large number (several tens of bolts) are provided.
It has been placed. For this purpose, the nut 15 is generally cylindrical and is configured to rotate through a groove 15a formed in its upper end. Note that the reference numeral 35 indicates a washer.

In order to confirm the safety of a nuclear reactor, the upper mirror 1 of the pressure vessel is removed and inspected inside about once a year, but in this case, all the nuts 15 attached to the dozens of bolts mentioned above must be removed. . In this case, when removing the nut, the rust generated on the threaded portion 13b of the bolt 13 is first removed and cleaned, and then the nut 15 is removed. Conventionally, this nut cleaning was carried out manually by workers using brushes, and this work in the pressure vessel installation area, which is a highly radioactive area, was extremely dangerous to the human body. Furthermore, the bolt used is approximately 150mm in diameter, approximately 1800mm in length, and weighs approximately 50mm.
Since the nuts are large (1 kg), the nuts are also quite heavy, which causes work efficiency to deteriorate.

The object of the present invention is to provide a device that can automatically clean bolts attached to a pressure vessel and automatically attach and detach nuts screwed onto the bolts. be.

In short, the present invention provides an automatic nut attachment/detachment device for opening and closing the upper mirror of a reactor pressure vessel, which is an annular guide rail along the upper mirror flange bolt of the reactor pressure vessel, and has support legs fixed to the upper mirror. a station having a drive device disposed on the guide rail and capable of moving independently on the guide rail; an arm provided on the station having a drive device movable in the diametrical direction and the vertical direction of the guide rail; This automatic nut attachment/detachment device is characterized by having a bolt cleaning device, a misalignment detector, a nut attachment/detachment device provided on each arm, and a remote automatic control device for controlling the device.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 2 and 3, 2 is a support leg, and 4 is a planar annular guide rail supported by this support leg 2. Both constitute the main body of the device, and the main body is connected to this support leg 2. It is fixed to a fixing part formed on the upper mirror 1 of the pressure vessel with bolts or the like. Reference numeral 6 denotes a plurality of stations (four in the illustrated case) attached to the guide rail 4, which are movable in the circumferential direction of the upper mirror 1 along the guide rail 4 in response to centering described later. It is structured like this. 3 is a drive device that moves the station 6 in the circumferential direction. Further, each station 6 can also be moved in the diametrical direction of the upper mirror 1 by a separate drive device 5.

FIG. 4 shows details of the station 6. In the figure, numerals 11a, 11b, and 11c are arms that are raised and lowered by the lifting device 7, numeral 9 is a bolt cleaning device attached to the arm 11a, and 10 is the arm 11c.
This is a nut attachment/detachment device attached to. 8 is a positioning device attached to the arm 11b.

Figures 5 and 6 show details of this positioning device. Two misalignment detectors 14 made of, for example, a differential transformer are attached to the side wall of the cylindrical main body of the device. It is effective to arrange the detector 14 so that the axis of each contact rod 14a faces the central axis of the bolt 13, and to arrange the axes of the contact rods of both detectors to be substantially perpendicular to each other. 12a is a two-axis addition/subtraction unit disposed within the remote control panel 12 for controlling the movement of the station 6.

The operation of the apparatus having the above configuration will be explained.

First, the device itself is transported to the upper mirror 1 using a crane or the like, and the device is attached to the upper mirror 1 using the support legs 2. Next, each station 6 is moved along the guide rail 4 and placed in a predetermined position, and then the positioning device is lowered to place a part of the bolt 13 in this positioning device, and the misalignment detector 14 is placed in the positioning device. Centering is performed using signals from When the centering is completed, the bolt cleaning device 9 is operated to clean the bolt 13, and then the nut 15 is removed by operating the nut removing device 10 having a nut turning device (not shown).

FIG. 7 shows another embodiment of the device described above. In this embodiment, a working scaffold 16 is attached to the upper part of the apparatus main body, and a supporting member 1 is attached from this scaffold.
Suspend the nut holder 18 through the nut holder 9, place the nut 15 removed in the above method on this holder 18, and when the removal work of all the nuts is completed, place the nut together with this holder in a predetermined place. It is designed to be transported to.

In addition to the contact type using a contact rod as described above, the misalignment detector may also be a non-contact type using ultrasonic waves, magnetic force, light, etc. In some cases, misalignment can be detected using a television camera, etc. May be detected.

The effects of implementing this invention are described below for each function of the constituent elements of the invention.

(b) This device is fixed to the upper mirror by support legs. Therefore, no space is required for attaching other members, and when attached to the upper mirror, it can be transported and stored together. Furthermore, compared to the case where a device or the like is attached to a flange using other means of transportation, there is no need to consider damage to the bolt, the attachment can be completed in a short time, and the bolt and flange are not damaged.

(b) In this device, the station moves on its own on guide rails, allowing it to move to a predetermined position accurately and quickly. Subtle position corrections are possible based on the detection results from the misalignment detector. Each station can be moved independently, so
The work can be carried out independently of other stations that are performing time-consuming work on this guide rail, and the work can be carried out by adjusting the number of bolts that each station is responsible for depending on how dirty the bolts are.

Since the method is not to rotate the station by installing a support from the center of the upper mirror flange and installing a station at the tip, it is possible to achieve high control accuracy without the burden of the weight of the support or problems with inertia. . Note that if the prop method is adopted, problems arise with the weight of the prop, the deflection of the prop, and the weight of the drive mechanism, and in particular, the accuracy of movement of the station deteriorates.

(c) The bolt cleaning device, bolt attachment/detachment device, and positioning device have arms that are movable in the diametrical direction of the guide rail and in the vertical direction perpendicular to the guide rail surface, so the positioning can be adjusted in the diametrical direction, vertical direction, and vertical direction. , there is no "shaking" of the device attached to the arm, and the bolt can be set quickly.
Centering is fast.

(d) Bolts are covered with deposits that contain radioactivity, such as rust, and if the deposits fall off when nuts are attached or removed, subsequent treatment is difficult. The bolt cleaning device removes deposits while suctioning, and then attaches and detaches the nut, so there is no exposure to radiation due to deposits, and there is no problem with post-treatment of deposits.

(e) This automatic nut attachment/detachment device is operated remotely and automatically, so the number of workers is small and there is no need to worry about workers being exposed to radiation.

[Brief explanation of drawings]

1 is a side view of the stud, FIG. 2 is a plan view of the device according to the invention, FIG. 3 is a side view of the device shown in FIG. 2, and FIG. 4 is a side view of the station;
FIG. 5 is a sectional view of the misalignment detector, FIG. 6 is a longitudinal sectional view of the misalignment detector, and FIG. 7 is a side view of the device of the present invention showing another embodiment. DESCRIPTION OF SYMBOLS 1... Upper mirror, 4... Guide rail, 6... Station, 8... Misalignment detector, 9... Bolt cleaning device, 10... Nut attachment/removal device, 11a, 11
b, 11c... Arm, 13... Studded bolt,
15...Natsuto, 16...Workbench, 18...Nutto stand.

Claims (1)

[Claims] 1. An automatic attachment/detachment device for nuts for opening and closing the upper mirror of a reactor pressure vessel, which is an annular guide rail along the upper mirror flange bolt of the reactor pressure vessel and has support legs fixed to the upper mirror; a station having a drive device arranged on a rail and capable of moving independently on the guide rail; an arm provided on the station and having a drive device for moving the guide rail in the diametrical direction and in the vertical direction; 1. An automatic nut attachment/detachment device comprising a bolt cleaning device, a misalignment detector, a nut attachment/detachment device, and a remote automatic control device for controlling the device.