JPS61182780A - Method of mounting control-rod driving device to control-roddriving device housing - 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 [Field of Application of the Invention] The present invention relates to a method of attaching a CHD flange to a control rod drive (hereinafter referred to as CHD) housing.

[Background of the invention]

CRD replacement work is performed during regular reactor inspections.

Since this work is carried out in an atmosphere with a high radiation dose rate, efforts are being made to reduce the radiation exposure of workers and save labor. Conventionally, a particular problem has been the CRD housing.
This is the work of tightening the mounting bolts when installing the HD flange.

In this work, after tightening the bolts, a torque detector is used to check the tightening force of each bolt one by one. However, the number of mounting bolts is in the hundreds, which poses a problem of radiation exposure to workers, so improvements are desired in that the work requires a large number of people over a long period of time.

[Purpose of the invention]

An object of the present invention is to save labor and reduce radiation exposure to workers during CHD replacement work.

[Summary of the invention]

The method of the present invention includes inserting a CRD into a CRD housing;
and a method for attaching a CHD to a CRD housing by attaching mounting bolts to the CRD housing flange portion and the CRD flange portion and tightening them using a bolt wrench provided on a head of a CRD attachment/detachment device.

The method is characterized in that the torque of the bolt wrench is adjusted in advance using a torque detector so that a predetermined fastening force is obtained, and then the mounting bolt is fastened using the bolt wrench. According to this method, there is no need to check the force when tightening the bolt after the bolt is fastened.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, a reactor pressure vessel 1 is installed on a pedestal 3 disposed within a containment vessel 2 (hereinafter referred to as PCv). A CARD housing 4 and a neutron flux measurement housing 5 are provided protruding from the lower part of the reactor pressure vessel 1 and form a part of the reactor pressure vessel 1 . C
The HD 6 is housed within the CRD housing 4. A space 7 is formed within the pedestal 3 below the reactor pressure vessel 1 .

An ejection port 8 for taking the CRD into and out of the space 7 is provided on the pedestal 3. A bracket 9 is provided to protrude from the side wall of the pedestal 3 within the space 7.

An annular rail is laid on the upper part of the bracket 9. The turning movement device 11 moves on the rail 1o. CR
The D exchange device 12 includes a turning movement device 11 and a CRD attachment/detachment device 1.
3 and a CRD handling device 14. C.R.D.
The attachment/detachment device 13 is composed of a traveling trolley 15 and an attachment/detachment head 16, and is used for attaching and detaching CRD mounting bolts, control rods, and CRD.
It has functions such as RD uncoupling operation, uncoupling confirmation, drain processing, and elevating and lowering the attachment/detachment head.

The CRD can be attached to and removed from the CRD housing 4. The CRD handling device 14 is composed of a traveling truck 17 and a mast 18, and has the functions of receiving, delivering, and overturning the CRD removed by the CRD attaching/detaching device 13. The CHD 6 that was overturned by the CRD handling device 14 is CR
It is held and loaded on the D-carrying cart 21 and is transported from the transport port 8 of the pedestal 2 through the through-hole 20 of the reactor containment vessel 2 via the bridge 19. When installing the CARD, the procedure described above is reversed.

As described above, the present invention relates to a CHD exchange device. CH
D Install and remove mounting bolts.

This invention provides a torque detection method for measuring the rotational force of a bolt wrench in order to equalize the bolt tightening force of a CRD attachment/detachment head.

Conventionally, the tightening force of CHD mounting bolts is

When replacing the CRD, the bolts are tightened with a bolt wrench and then tightened further and the torque is detected as it rotates, or the torque is set to a constant torque from the beginning and tightened using a torque detector. However, the variation in the tightening force is large, and it is also unfavorable from the viewpoint of reducing radiation exposure and saving labor.

Due to the problem of reactor water leakage from the reactor pressure vessel and the seat surface of the CHD, the tightening torque of the CRD mounting bolts is strictly regulated so that the variation in the tightening torque is several percent or more. Therefore, when tightening the eight mounting bolts, a method is adopted in which the bolts are tightened in stages, starting with a smaller torque and gradually increasing to the specified torque. The work efficiency is extremely poor because the detectors are installed in a row. Therefore, the tightening torque varies widely, causing many troubles.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIGS. 2 and 3 show a state in which a torque detector is attached to the CRD attachment/detachment head.

The attachment/detachment head 16 is an uncoupling mechanism 22 between the control rod and the CRD. It is equipped with an uncoupling detector 23 and a drain processing mechanism 24, and has a function of attaching and detaching the CRD mounting bolt. The CRD mounting bolts are attached and detached by rotating the bolt wrench 27 using the air motor 25 through the sleeve 26. As mentioned above, the rotational force of the bolt wrench 27 is
Since it depends on the air pressure and amount of air supplied to the air motors 5, not all air motors 25 have the same rotational force.

Therefore, the tightening force of the CRD mounting bolts is not always uniform, and the rotational force is easily measured and supplied to the air motor 25.

By adjusting the air pressure and air volume, the CRD mounting bolts can be tightened using multiple air motors 25.
The torque adjustment is completed so that the rotational force of the motor does not vary. A torque detector 29 is attached to the bolt wrenches 27 and 28 located diagonally on the detachable head 16, and the air motor 25 is rotationally driven to apply rotational force to the bolt wrench 27. The torque detector 29 is configured to detect the output torque of the air motor 25. 31 is a fulcrum for preventing the torque detector 29 from being swung around by the rotational force of the air motor 25. The frame 33 and the torque wrench 30 are fixed by a shaft 32. In this way, the torque detectors 29 are sequentially attached to the bolt wrenches 27 of the air motors 25 located diagonally to detect the output torque of each air motor 25, and the CRD
Adjust the tightening torque of the mounting bolts so that they are uniform.

When adjusting the torque, the air motor 25 connected to the torque detector 29 is driven, and while watching the indicator of the torque detector 29, the rotation is continued until a predetermined torque is reached, and then stalled (stopped). Air motor 25 at the time
Tightening is performed by determining the force as a predetermined torque and adjusting the air pressure of the air motor 25. As a result, the set torque can be obtained during subsequent bolt tightening, and a constant tightening force can always be obtained.

FIG. 4 shows details of the torque detector main 1 used in the above embodiment. This uses a known torque detector. However, some parts have been modified for convenience of installation. An adapter 35 is attached to the input shaft 34 of the torque wrench 30 and engaged with the bolt wrench 27, and the fulcrum 31 of the bolt wrench 28 is engaged. The output torque of the air motor 25 is displayed on a torque indicator 36.

〔Effect of the invention〕

According to the present invention, the output torque of each air motor can be easily detected by attaching the torque detector to the bolt wrench of the attachment/detachment head, resulting in labor savings and reduction in radiation exposure.

[Brief explanation of the drawing]

Figure 1 is an overall conceptual diagram of the CRD exchange device, Figure 2 is the CHD
FIG. 3 is a view taken along the line A--A in FIG. 2, and FIG. 4 is a detailed sectional view of the torque detector portion. DESCRIPTION OF SYMBOLS 16... Detachable head, 22... Uncoupling mechanism, 23... Uncoupling detector, 24... Drain processing mechanism, 25... Air motor, 26... Sleeve, 27.28... ...Bolt wrench, 29...Torque detector. 30...torque wrench, 31...fulcrum, 32...
Axis, 33... Frame, 34... Input axis, 35...
・Adapter, 36...Torque indicator.

Claims (1)

[Claims] 1. Insert the control rod drive device into the control rod drive device housing, and attach mounting bolts to the CRD housing flange portion and the flange portion of the control rod drive device, and install the mounting bolts on the head of the control rod drive device attachment/detachment device. In a method of attaching a control rod drive device to a control rod drive device housing by tightening using a bolt wrench, the torque of the bolt wrench is adjusted in advance using a torque detector so that a predetermined tightening force is obtained. and then tightening the mounting bolt using the bolt wrench.