JPS6037259Y2 - shroud head bolt wrench - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a shroud rad bolt wrench used for tightening and loosening the shroud rad bolt that tightens the shroud head of a boiling water nuclear reactor.

Generally, as shown in FIG. 1, a boiling water reactor has a cylindrical shroud 2 housed within a reactor pressure vessel 1. Within this shroud 2, fuel assemblies and other core components (not shown) It is designed to accommodate.

A shroud head 2a is detachably attached to the upper end of the shroud 2.

3 is a steam separator, and 3a is a stand pipe communicating with the steam separator 3.

The shroud head 2a is fixed at its peripheral edge to a plurality of shrouds with Radbolts 4 (only two are shown in the drawing).

This shroud bolt 4 is a device for tightening together a connecting seat 5 formed at the upper peripheral edge of the shroud 2 and a connecting seat 6 formed at the lower end peripheral edge of the shroud head 2, and is shown in FIGS. 2 to 4. It is configured as shown.

That is, 7 is a sleeve body with both upper and lower ends open, and a bolt body 8 is provided to penetrate through this sleeve body 7 so as to be movable in the axial direction.

A tightening nut 10 is attached to the threaded portion 9 at the upper end of the bolt body 8.
are screwed together, and by tightening this tightening nut 10, the connecting seat 5 , 6 are connected to each other.

Further, a nut lock member 13 is provided above the tightening nut 10 to prevent the tightening nut 10 from loosening.

This nut lock member 13 is prevented from rotating at the upper end of the sleeve body 7 by a pin 14 so that it can only move in the vertical direction.

By fitting the corners of the tightening nut 10 into the wavy engagement recesses 15 formed on the inner peripheral surface of the nut locking member 13, the tightening nut 10 is prevented from rotating.

This nut lock member 13 is always urged upward by a spring 16, and only when turning the tightening nut 10, the nut lock member 13 is inserted into the socket portion of the shroud head bolt wrench against the elastic force of the spring 16. After being pushed down by remote control, the tightening nut 10 is rotated by this socket portion.

The Radbolt 4 to the shroud configured as above is
During fuel exchange or periodic inspection, the tightening nuts 10 are tightened or 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 relies on visual inspection through reactor water, so the working conditions are extremely severe. In particular, as mentioned above, the fitting of the nut lock member 13 to the tightening nut 10 cannot be accurately confirmed by visual inspection. Confirmation work is difficult and causes the work to take a long time.

Moreover, when the reactor water becomes cloudy, the work has to be interrupted, causing a delay in the work, which in turn becomes a factor in reducing the operating rate of the reactor.

This idea was made based on the above circumstances, and its purpose is to make it possible to easily confirm the position of the nut lock member from outside the reactor, and to facilitate tightening and loosening of the shroud head bolts. Our goal is to provide a rad bolt wrench for shrouds that makes it possible.

That is, this invention provides a sensing part in the socket part of the wrench body that is activated when the nut lock member is pressed, and also provides an indicator to display the detection signal from this sensing part to the outside of the reactor. This is a shroud head bolt wrench that allows the status of the nut lock member to be known from outside the reactor through a display.

This invention will be explained below based on an embodiment shown in FIGS. 5 to 7.

In the figure, 20 indicates a wrench body.

This wrench main body 20 is suspended into the reactor by a hanging tool 21, and has a cylindrical shape over almost the entire length, and its axially intermediate portion is connected to an upper half portion 20a via a connecting portion 22. The lower half 20b can be separated.

This connecting portion 22 has flanges 23, 24 connected to each other by swing bolts 25, and can be used by connecting to a length necessary for handling the Radbolt 4 to the shroud.

Further, a bundle 26, 26 for rotational operation is provided at the upper end of the wrench body 20.

This bundle 26.26 can be folded vertically about an axis 27.27 to facilitate storage when not in use.

The bundle 26.26 is also provided with a switchable ratchet mechanism 28 so that the direction of rotation of the wrench body 20 can be selected and rotated only in that direction.

Furthermore, a positioning lever 30 is provided at the upper end of the wrench body 20.

This positioning lever 30 is connected to an internal tube 31 inserted into the wrench body 20.

This internal tube 31 extends to the lower end of the wrench body 20, and a fitting groove (not shown) provided on the lower surface of the internal tube 31 is connected to a convex portion 4a provided on the upper end of the shroud head bolt 4.
It can be mated to.

Therefore, by looking at the orientation of the positioning lever 30, the orientation of the tightening portion 11 provided at the lower end of the rad port 4 to the shroud can be confirmed.

Further, a battery box 32 is attached to the upper end of the wrench body 20.

This battery box 32 has an indicator lamp 3 that blinks depending on the on/off of limit switches 44 and 52, which will be described later.
3.34, and also houses a battery that serves as a power source for the lamp.

A socket portion 35 is provided at the lower end of the wrench body 20.

This socket portion 35 has a socket hole 36 shaped to fit into the tightening nut 10, and can be inserted into the tightening nut 10 from above, and also pushes down the nut locking member 13 with its lower end surface 37. It is now possible to do so.

Further, the inner surface of the socket hole 36 has a tapered support surface 38 for seating the upper end tapered surface 10a of the tightening nut 10.

Further, a nut locking member 13 is provided in the socket portion 35.
The first sensing section 40.4 operates when pressed.
0 and a second sensing part 41.41 which is activated when the tapered support surface 38 is seated on the tightening nut 10.

As shown in FIG. 6, the first sensing portion 40.40 includes sensing protrusions 42.42 whose tips protrude retractably from the lower end surface 37 of the socket portion 35, and these sensing protrusions 42.42.
．． It consists of a spring 43.43 that always urges the sensor 42 downward, and a limit switch 44.44 that is activated when the sensing protrusion 42.42 is pushed upward.

The signal lines of these limit switches 44 and 44 are connected to the guide tube 4.
5, 45 and is led to the battery box 32, and is connected to a first indicator lamp 33 as an example of an indicator.

On the other hand, as shown in FIG. 7, the second sensing portion 41.41 is rotatable about a shaft 48.48 and is a rocking sensing projection protruding from the inner surface of the tapered support surface 38. child 49
．． 49, an intermediate rod 50.50 that moves up and down according to the rotational position of the swing sensing protrusion 49.49, and a spring 51.50 that constantly biases these intermediate rods 50, 50 downward.
51 and a limit switch 52.52 which is activated in the raised position of the intermediate rod 50.50.

The signal lines of these limit switches 52, 52 are passed through the guide tubes 53, 53, led to the battery box 32, and connected to the second indicator lamp 34.

Next, the operation of the apparatus of the above embodiment will be explained.

For example, using a hoist such as a fuel exchanger, the wrench body 20 is lowered toward the tightening nut 10.

Then, when the socket part 35 is fitted into the tightening nut 10 from above and the lower surface of the socket part 35 pushes down the nut locking member 13, the sensing protrusion 42 of the first sensing part 40, 40,
42 is raised, the limit switches 44 and 44 are activated, and the first indicator lamp 33 is lit.

Therefore, it is possible to first confirm that the nut lock member 13 has been pressed down.

When the socket part 35 is further lowered, the upper end tapered surface 10a of the tightening nut 10 is seated on the tapered support surface 38, and the swing sensing protrusions 49, 49 of the second sensing part 41.degree. Pushed in the direction, the intermediate rod 50.50
The limit switches 52, 52 are actuated to push up, causing the second indicator lamp 34 to light up.

Therefore, it can be confirmed that the socket part 35 is completely inserted into the tightening nut 10.

In this state, the nut lock member 13 is detached from the tightening nut 10, so that the tightening nut 10 can be turned.

Next, the wrench body 20 is rotated around the axis using the handle 26, 26, and the tightening lug 10 is rotated and loosened, so that the lower end tightening portion 11 of the shroud head bolt 4 and the clamp 12 are tightened. The distance increases and it becomes possible to remove it from the connecting seats 5 and 6.

On the other hand, when tightening the tightening nut 10, the socket portion 35 is rotated in the opposite direction to that described above.

When the socket portion 35 is raised after tightening the tightening nut 10, the tightening nut 10 first tightens onto the tapered support surface 3.
8, the limit switch 52.52 of the second sensing section 41.41 is activated, and this state can be confirmed by the second indicator lamp 34.

When the socket portion 35 further rises, the nut lock member 1
3 is raised by the elastic force of the spring 16 and is fitted into the tightening nut 10.

When the nut lock member 13 rises to its normal position and is completely fitted into the tightening nut 10, the lower surface of the socket portion 35 immediately separates from the nut lock member 13.

Therefore, at this time, the sensing protrusion 4 of the first sensing section 40.40
2.42 is lowered, the limit switch 44.44 is activated, and the first indicator lamp 33 is turned off, so that it can be confirmed that the socket portion 35 has separated from the nut lock member 13.

On the other hand, if the nut lock member 13 is not properly fitted into the tightening nut 10 and cannot be raised to the normal position due to, for example, being caught on the lower end of the tightening nut 10, the taper shape of the socket portion 35 may As soon as the support surface 38 separates from the tightening nut 10, the lower end surface 37 of the socket portion 35 separates from the nut locking member 13.

That is, immediately after the first indicator lamp 33 is turned off, the second indicator lamp 33 is turned off.
Since the indicator lamp 34 also goes out, by monitoring the blinking timing of both indicator lamps 34, it is easy to check from outside the reactor whether or not the nut lock member 13 is correctly fitted to the tightening nut 10. You can know.

Therefore, it goes without saying that the work of tightening and loosening the tightening nut 10 can be done quickly, and there is no risk of finishing the work with the nut locking member 13 not properly fitted to the tightening nut 10. , it becomes possible to securely prevent loosening.

Note that the blinking relationship of the display lamps 33 and 34 may be reversed.

For example, the first limit switch 44, 44 illuminates the indicator lamp 33 when pressed by the sensing barb 42, 42, and the second limit switch 52.52 when pressed by the intermediate rod 50.50. The display lamp 34 may be turned off at the same time.

Alternatively, the relationship may be the opposite, as long as the operator can judge the state of the nut lock member 13 by blinking the indicator lamps 33 and 34.

In addition, in the above embodiment, two first sensing sections and two second sensing sections were provided in order to improve detection reliability, but even if there were only one each, the intended purpose could be distantly related. It is.

Furthermore, instead of the limit switch, a reed switch or the like operated by magnetic force may be used as the sensing section.

Further, the display device is not limited to a display lamp, but may be a display device such as a CRT so that the display can be viewed from a remote location, or a sound such as a buzzer may be used.

As explained above, this device is equipped with a sensing section in the socket of the wrench body that operates when the nut lock member is pressed, and an indicator that displays the detection signal output from this sensing section outside the reactor. By providing this indicator, workers can know the status of the nutlock members from outside the reactor, and they can easily check the status of the nutlock members without having to visually check the nutlock members through the reactor water. Because it can be grasped, workability is good and it is not affected by turbidity of reactor water.

Therefore, it is possible to quickly tighten and loosen the shroud head bolts even under the harsh working conditions of remote work under high radiation control and in reactor water, contributing to the reduction of radiation exposure of workers. This makes it possible to shorten the time required for periodic inspections or fuel replacement work, and is also effective in improving the operating rate of the reactor.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a part of the reactor, Figure 2 is a longitudinal sectional view of the Radbolt to the shroud, Figure 3 is a side view partially showing the tightening nut, and Figure 4 is the same tightening nut. A plan view of the nut part. Figures 5 to 7 show an embodiment of this invention.
6 is an enlarged view of the lower end thereof, and FIG. 7 is a sectional view taken along the line ``--'' in FIG. 5. 4...Shroud head bolt, 10...
... Tightening nut, 13... Nut lock member,
20...Wrench body, 26...Handle, 33.34...Indication lamp (indicator), 3
5...Socket part, 37...Lower end surface,
40...First sensing section, 41...Second
sensing part.

Claims (3)

[Scope of utility model registration request] (1) A wrench body equipped with a handle for rotating operation at the upper end, and a wrench body provided at the lower end of the wrench body that is removably fitted into the tightening nut of the shroud head bolt and tightened by the lower end surface. A socket part for pushing down the nut lock member on the upper part of the attached nut, a sensing part provided in this socket part and activated when the nut lock member is pressed, and an indicator for displaying a detection signal from this sensing part on the outside of the reactor. A shroud head bolt wrench characterized by the following: (2) The sensing section is characterized by using a sensing protrusion whose tip part protrudes retractably from the lower surface of the socket, and a limit switch that operates according to the vertical position of the sensing protrusion. Scope of Claim for Utility Model Registration (1)
Shroud head bolt wrench as described in section. (3) Utility model registration claim No. 2, characterized in that the indicator is an indicator lamp that blinks depending on whether the limit switch is turned on or off, and the indicator lamp is arranged on the upper part of the wrench body. Radbolt wrench to the shroud described in section.