JPS6262289A - Shroud head bolt treater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a shroud head bolt handling device that handles shroud bolts that connect bolts to the shroud of a boiling water nuclear reactor (hereinafter referred to as BWR).

[Technical Background of the Invention] A conventional example will be described below with reference to FIGS. 4 to 7. FIG. 4 is a sectional view showing a part of the BWR, and the reference numeral 1 in the figure is a reactor pressure vessel. A cylindrical shroud 2 is installed within the reactor pressure vessel 1, and a reactor core 3 is accommodated within the shroud 2. This core 3 is composed of a plurality of fuel assemblies, control rods, etc. (not shown).

A shroud head 2a is removably installed at the upper end of the shroud 2. Also this shroud head 2
A steam separator 5 is installed above the stand pipe 4 via a stand pipe 4. The coolant, which has passed through the reactor core 3 and has been heated to a two-phase flow state of water and steam, is introduced into the steam separator 4 and separated into steam and water. The shroud head 2a is fixed by a plurality of shroud head bolts 5 (only two are shown in the top view). That is, the shroud head bolt 5 fastens together the connecting seat 6 formed at the upper peripheral edge of the shroud 2 and the connecting seat 7 formed at the lower peripheral edge of the shroud head 2a.

The structure of the shroud head bolt 5 will be explained in more detail below with reference to FIGS. 5 to 7.

Reference numeral 8 in FIG. 5 is a sleeve body with both upper and lower ends open, and a bolt body 9 is disposed through the sleeve body 8 so as to be movable in the axial direction. A tightening nut 11 is screwed into a threaded portion 10 at the upper end of the bolt body 9. By tightening this fastening nut 11, the connecting parts 6 and 7 are interconnected between the tightening part 12 provided at the lower end of the bolt body 9 and the clamp 13 provided at the lower end of the sleeve body 8. .

A nut lock member 14 is installed on the outer circumferential side of the tightening nut 11 to prevent the tightening nut 11 from loosening. As shown in FIG. 6, this nut lock member 14 is secured to the upper end of the sleeve body 8 by a pin 15 so that it can move only in the vertical direction. The corner of the tightening nut 11 is fitted into the wavy engagement recess 16 formed on the inner peripheral surface of the nut locking member 14, thereby preventing the tightening nut 11 from rotating. The nut lock member 14
is constantly urged upward by a spring 17,
The nut lock member 14 is pushed down against the elastic force of the spring 17 using the socket portion of the shroud head bolt wrench, and in this state, the shroud head bolt wrench is rotated to rotate the tightening nut 11.

[Problems with background technology] According to the above configuration, there were the following problems.

Generally, during fuel exchange or periodic inspection, the tightening nuts 11 are tightened and loosened by remote control from the upper part of the reactor while the reactor pressure vessel 1 is filled with water. However, this work is under high radiation control and requires visual observation through reactor water, making the work conditions extremely difficult, and the number of rotations of the tightening nut 11 must be determined by the worker's memory throughout the work period. There was a problem. However, it is difficult for the worker □ to always know the rotation speed of the tightening nut 11, and the work also takes a long time. The operating rate was decreasing.

[Object of the Invention] The present invention has been made based on the above points, and its object is to tighten and tighten shroud head bolts by automatically detecting the rotation speed of the tightening nut of the shroud head bolt. An object of the present invention is to provide a shroud head bolt handling device that can improve the workability and reliability of loosening work, shorten work time, reduce radiation exposure to workers, and improve plant availability. .

[Summary of the Invention] That is, the shroud head bolt handling device according to the present invention includes an inner wrench whose lower end is removably engaged with the upper end convex portion of the shroud head bolt, and an inner wrench which is arranged on the outer peripheral side of the inner wrench and whose upper end It is installed between an outer wrench that has a rotation handle and whose lower end is removably engaged with the tightening nut of the shroud head bolt, and these inner and outer wrenches to detect the rotational speed of the tightening nut. The invention is characterized in that it is equipped with a rotation speed detection mechanism.

In other words, a rotation speed detection mechanism is installed between the inner wrench and the outer wrench, and this rotation speed detection mechanism detects the rotation speed of the tightening nut without relying on the worker's memory as in the past, and allows tightening and loosening. This is to make the work more reliable.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of a shroud head bolt handling device according to this embodiment. Reference numeral 101 in the figure indicates an inner wrench, and this inner wrench 101 is detachably coupled to the upper end convex portion 5a of the shroud head bolt 5. On the other hand, the reference numeral 102 in the figure indicates an outer wrench, and this outer wrench 10
2 is removably connected to the tightening nut 11. The shroud head bolt handling device according to this embodiment includes both of these wrenches 101 and 102, and both wrenches 101 and 102.
The rotation speed detection mechanism 103 is interposed between the two and detects the rotation speed of the tightening nut 11. The configurations of the inner wrench 101, outer wrench 102, and rotation speed detection mechanism 103 will be described in detail below.

As shown in FIG. 2, the inner wrench 101 has a lower end groove 111 at its lowermost end, which is detachably connected to the upper end protrusion 5a of the shroud head bolt 5. This lower end groove portion 111 is connected to a lower inner wrench 112,
Also, above the lower inner wrench 112 is an intermediate inner wrench 1.
13 are connected. And this middle inner wrench 113
An upper inner wrench 114 and an inner wrench handle 115 for restraining rotation of the inner wrench 101 are connected above the upper inner wrench 114 . In addition, each of the above inner wrenches 112 and 113
．． 114 is configured to automatically engage when the outside wrench 102 is connected.

Next, the configuration of the outer wrench 102 will be explained. As shown in FIG. 1, the outer wrench 102 includes a socket portion 121 that is removably connected to the tightening nut 11 of the shroud head bolt 5, a lower outer wrench 122 that supports this socket portion 121, and a lower outer wrench. an intermediate outer wrench 123 supporting the intermediate outer wrench 122;
3 and an upper outer wrench 124 attached to the upper part of the holder. An outer wrench handle 125 and a torque wrench 126 for rotating the tightening nut 11 of the shroud head bolt 5 are attached to the upper outer wrench 124. Further, a hanging tool 131 is attached to the upper part of the upper outer wrench 124, and a wire rope from an auxiliary hoist of a fuel exchanger (not shown) is connected to this hanging tool 131 to lift and suspend the shroud head bolt 5. Eggplant. The lower outer wrench 122, the intermediate outer wrench 123, and the upper outer wrench 124 are connected by bolts 141 and nuts 142.

Next, the configuration of the rotation speed detection device 103 will be explained with reference to FIG. 3. Reference numeral 151 in the figure is a rotational speed meter, and this rotational speed meter 151 is attached to a hanging tool 152 of the outer wrench 102 via a bracket 153. A short tooth type (second gear) 155 is fixed to the upper end of the shaft 154 of the rotation speed meter 151, and a long gear (first gear) fixed to the upper end of the inner wrench 101 is attached to this short tooth type 155. gear) 156. That is, the inner wrench 101
The shroud head bolt 5 is restrained from rotating, and the tightening nut 11 is rotated by the outer wrench 102. At this time, the similar gear 155 attempts to revolve around the long gear 156 as the outer wrench 102 rotates. On the other hand, the long gear 156 does not rotate because the inner wrench 101 is not rotating, so the short tooth type 155 revolves around the long gear 156 while rotating. This detects the number of rotations of the outer wrench 102 and, in turn, the number of rotations of the tightening nut 11.

The operation will be explained based on the above configuration. For example, when connecting the shroud 2 and the shroud head 2a, first the handling device according to this embodiment is suspended in the direction of the shroud head bolt 5 using the auxiliary hoist of the fuel exchanger. Then, the lower end groove portion 111 of the inner wrench 101 is engaged with the upper end convex portion 5a of the shroud head bolt 5.

Next, the socket portion 121 of the outer wrench 102 is engaged with the tightening nut 11. and inner wrench handle 11
5 to restrain the movement of the shroud head bolt 5. Next, the outer wrench handle 125 is rotated and the tightening nut 11 is rotated and tightened to connect the shroud 2 and the shroud head 2a. At that time, torque wrench 12
6 to manage the rotational torque. At the same time, the rotation of the outer wrench 102 causes the revolution counter 151 to rotate.

In other words, since the inner wrench 101 does not rotate, the long gear 1
56 does not rotate. Therefore, the short tooth type 155 meshed with the long gear 156 revolves around the long gear 156 while rotating. As a result, the rotating shirt l-15 with a rotation count of 151
4 rotates, and the outer wrench 102 and the tightening nut 1
1 rotation speed is detected and displayed.

According to this embodiment, the following descent can be achieved. That is, the inner wrench 101 and the outer wrench 102
A rotation speed detection mechanism 103 is installed between the outer wrench 102 and the rotation speed of the tightening nut 11 by this rotation speed detection mechanism 103.
The shroud head bolt 5 can be tightened and loosened reliably, and there is no need to rely on the worker's memory as in the past, improving work efficiency and improving the reliability of the equipment. You can also try to improve your performance.

This makes it possible to quickly tighten and loosen the shroud head bolts 5 even under high radiation control and remote work in reactor water, which is extremely effective in reducing radiation exposure for workers. At the same time, it is possible to improve the operating rate of the plant by shortening the working time.

[Effects of the Invention] As detailed above, according to the shroud head bolt handling device according to the present invention, the rotation speed of the tightening nut can be accurately detected without relying on the memory of the worker as in the past. Tightening and loosening operations can be made more reliable, thereby not only improving work efficiency, but also reducing exposure to radiation for workers and improving the operating rate of the plant by shortening the working time.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention.
The figure is a perspective view of the shroud head bolt handling device, Figure 2 is a sectional view showing the lower part of the shroud head bolt handling device in detail, Figure 3 is a sectional view showing the upper part of the shroud head bolt handling device in detail, and Figure 4 is a partial cross-sectional view of a boiling water reactor, Figure 5 is a longitudinal cross-sectional view of a shroud head bolt,
Figure 6 is a side view partially showing the tightening nut section;
The figure is a side view of the tightening nut portion. 101...Inner wrench, 102...Outer wrench, 1
03... Rotation speed detection mechanism. Applicant's agent Patent attorney Shikihiko Suzutsuta Figure 6 Δ power Mibe □'

Claims (2)

[Claims] (1) An inner wrench whose lower end is removably engaged with the upper convex part of the shroud head bolt, and a handle for rotating operation located on the outer circumference of the inner wrench at its upper end, whose lower end is attached to the shroud head bolt. The invention is characterized by comprising an outer wrench that is detachably engaged with the tightening nut, and a rotation speed detection mechanism that is installed between the inner wrench and the outer wrench and detects the rotation speed of the tightening nut. Shroud head bolt handling device. (2) The rotation speed detection mechanism includes a first gear fixed to the upper end of the inner wrench, a rotation speed indicator attached to the upper end of the outer wrench, and a rotation speed indicator fixed to the rotating shaft of the rotation speed indicator. 2. The shroud head bolt handling device according to claim 1, further comprising a second gear that meshes with the first gear.