JPS6097297A - Exchanger for control-rod driving mechanism - 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 CR/D exchange device, and particularly to a CR/D exchange device for quickly attaching and detaching a CRD and aligning the device.
Relating to a switching device.

[Background of the invention]

Conventionally, the CRD is installed by screwing eight mounting bolts into the C Tt D housing, which is integrally welded to the reactor pressure vessel, using eight air motors. Therefore, when installing it, it is necessary to visually check the alignment of the CRD/-Using's lozenge hole and the mounting bolt, and when removing it, it is necessary to visually check the alignment of the hexagonal hole of the mounting bolt and the hexagonal wrench on the detachable head. With torque (
Depending on the looseness, reactor water leaks from the CRD mounting surface, making it necessary to adjust the O-ring or to reduce the force of sliding the sealing surface.In existing plants, CRD replacement equipment is installed. The pedestal room at the bottom of the reactor is IR/I
-] The radiation dose rate has been rising in Vietnam, and entry into the pedestal room is limited to 5 to 6 minutes/person/day for CR/D replacement work or equipment maintenance inspection. Ru.

With the current equipment, the alignment of the CRD attachment/detachment device, CB, and D housing, as well as the alignment of the screw holes and screws, must be done by final visual confirmation by the operator. By reducing the number of attachments and detachments, it is possible to reduce the radiation exposure of workers and shorten the time required to replace CRDs, thereby achieving the B'WR improvement standardization target of 80 days for periodic inspections.

[Purpose of the invention]

The object of the present invention is to fix the CRD by tightening and fixing it by a cap nut method instead of using a mounting bolt, and to prevent leakage by pressing a metal O-ring provided on the seat surface with equal pressure. To enable a CRD to be easily attached and detached only by positioning a CRD housing surface attachment/detachment device.

[Summary of the invention]

Conventionally, CRDs have been installed using eight mounting bolts. If the eight tightening torques vary from the specified range, reactor water will leak from the sealing surface. The present invention eliminates the tightening of multiple bolts, uses a detachable head to press the sealing surface with equal pressure, and fixes it with a cap nut. This makes alignment easier and reduces radiation exposure for workers. 9? ! ! Totally reduces the time required to attach and detach several mounting bolts, speeding up CRD replacement work and contributing to shorter periodic inspections.

[Embodiments of the invention]

An embodiment of the present invention will be explained below with reference to the drawings. In Figure 1,
A reactor pressure vessel (hereinafter referred to as RPV) 1 is installed on a pedestal 3 disposed within a reactor containment vessel (hereinafter referred to as PC) 2. A CRD housing 4 and a neutron measurement housing 5 are provided to protrude from the lower part of the RPVl. The CR, D housing 4 and the neutron measurement housing 5 also form part of the RPVl.

A control rod drive mechanism 6 (hereinafter referred to as CRD) is housed within the CR,D housing 4. A space 7 is formed within the pedestal 3 below within the RPVl. CRD6
The pedestal 3 is provided with an entrance 8 for loading and unloading into and out of the e-space 7.

A bracket 9 is provided to protrude from the side wall of the pedestal 3 within the space 7, and an annular rail 1 is provided on the upper part of the bracket 9.
0 is set.

C) The rotating moving cart 11 fully rotates on the rail 10.
1. The D exchange device fi12 is composed of a rotating moving cart 11, a CR attaching/detaching device 13, and a CR/D handling device 14.

The CR, D attachment/detachment device 13 includes a traveling trolley 15 and an attachment/detachment head 1.
6, includes lifting and lowering tightening of CRD, drain processing for all drains from CB, D housing 4 and CRD 6, rotating machine HBk of attachment/detachment head 16, CR, I) attachment and detachment of CRD to housing 4. can be done.

C) (D handling device 14 is a traveling trolley 17 and mass) 1
8C) (D, consisting of a transportation cart 21,
l, D Installation and removal [CRI removed in step 13)].

It has a delivery and rollover mechanism, and is structured so that the CRD removed by the CRD attachment/detachment device 13 can be automatically transferred to the CRD transport cart 21 mounted on the CRD handling device 14. and CRD handling device 14
The CRD transport cart 21 above is a CI (, D handling device 1)
Separate from 4 and POY with CRDG still loaded.
3.It is configured so that it can be carried in and out. 19 is a loading/unloading bridge, and 20 is a through hole provided in POY3.

In CR and D exchange, after the CRD attachment/detachment device 13 is accurately positioned at the position of the CRD to be exchanged, the CRD becomes ready for removal or attachment.

First, the turning moving trolley 11'kO degree turns, then CI (,D
The attachment/detachment device 13 is driven (R) to perform so-called R-0 control, and the attachment/detachment head 16 is brought directly below the target CRD. Further, the control rod and the CRD of the detachable head 16 are uncoupled, the mounting bolts and other parts are loosened, and a drain process is performed, and the CRD is removed.

A conventional attachment/detachment head will be explained with reference to FIG.

FIG. 2 shows that the CRD 6 to be replaced and the detachable head 16 have been accurately aligned, and the CRD mounting bolt 22 has also been completely aligned.
The hexagonal hole 23 and the hexagonal part of the bolt wrench 24 are shown fitted together. The procedure for removing the CRD6 will be explained below.

The turning moving cart 11 and the attachment/detachment device 13 are controlled by R-○,
Position it directly below the CRD to be replaced.

From this position, the attachment/detachment head 16 is raised by a lifting drive mechanism (not shown) of the CRD attachment/detachment device 13, and the attachment/detachment head 16 is accurately aligned with the CRD 6.

To align the detachable head 16 and CR, D6, simultaneously seat the retainer 25 of the detachable head 16 and the tapered portion 26 of the CRD 6, and align the hexagonal holes 23 of the eight CRD mounting bolts 22 with the bolt wrench 24. Therefore, a compression spring 27 is built into the lower part of the bolt wrench 24, and as soon as the bolt wrench is rotated at low speed and the hexagons are aligned accurately, the compression spring 27 The bolt wrench 24 is suddenly pushed up by the releasing force of the bolt, and is fitted into the hexagonal hole 23 of the bolt. This operation fcRD mounting bolt 2
It is repeated as many times as 2 (8 pieces).

The angular alignment of the hexagonal hole 23 and bolt wrench 24 is CR.
The attachment/detachment head 16 is rotated clockwise or counterclockwise by a head rotation mechanism 28 provided in the D attachment/detachment device 13.

As mentioned above, R-0 rough positioning is performed by the rotation O of the rotation movement device 11 and the travel R of the attachment/detachment device 13, then the alignment of the attachment/detachment head 16, CR, and D6, and the eight bolt hexagonal holes 23 and the bolts. The positioning of the wrench 24 and the three-step procedure are complicated, and the positioning of the bolt, bolt wrench, and hexagonal portion must rely on visual confirmation, which requires an experienced worker.

In the space 7 of the R and PV lower pedestal 3 where the CRD exchange equipment is installed, the radiation dose rate is IR,/1 (r), which is a very short period of 5 to 6 minutes/person/day, as there are existing plants with high radiation doses. Entry to the area is restricted at certain times.In addition, the workers are inside the pedestal, where water from the reactor is falling, so they must wear full masks and PVC suits while pulling the airline hoses to prevent internal and external exposure. In this way, the replacement work is being carried out in extremely poor conditions.

From the perspective of reducing radiation exposure for workers and shortening periodic inspections, it is necessary to perform the above positioning confirmation in a short time, and it is also possible to perform simple tasks in a short time, including attaching and detaching bolts, uncoupling, drain processing, etc. This is something that is strongly requested to be done.

When installing C11'LD, when the detachable head 16 rises and its positioning is completed, the %CRD housing 4 and CR,
In order to press the metal O-ring 30 fixed to the seat surface 29 of D6 to a specified crushing distance, the attachment/detachment head 1 is used.
6, compression tightening is an important point. Therefore, when the attachment/detachment head 16 is raised, it is pressed so that the seat surface 29 of the CRD 6 collides with the CR, D housing 4 with a required load, crushing the metal O-ring 30 and sealing the reactor water.

Conventionally, the lifting force of the detachable head 16 is limited by stopping the drive motor by detecting an overload from the output shaft of the elevating drive motor via a differential gear mechanism.
And it does not buffer the collision force of the seat surface 29 of CRD4,
There is a disadvantage that an impact force is applied to the rack and pinion of the lifting drive.

A drain treatment mechanism 31 is provided in the CHD attachment/detachment head 16 in order to treat drain water that flows out from inside the reactor through the entire CRD housing 4 when the CRD is attached or removed. During the drain process, the CRD housing 4 and CB, D6 and CR, D6 and the detachable head 16 are connected, the drain sleeve 33 is raised by the air cylinder 32, and CI't,
A seal ring 34 prevents the particles from scattering from the contact portion (seat surface) 29 between the D housing 4 and the CRD 6 to the surroundings. This drain processing mechanism is also a narrow space where the CR, D housing 4, neutron measurement housing 5, etc. are lined up, and it is not easy to configure the air cylinder drain sleeve and seal ring, and the 5 attachment/detachment head is complicated.

Due to its large size, there are major problems in terms of operability, especially in terms of maintenance of the device.

The CRD mounting bolts 22 are attached and detached by controlling and driving eight air motors 25 provided on the attachment/detachment head simultaneously, two diagonally, or one at a time.
I am doing all the loosening and installing and removing the CRD.

It is important to tighten and loosen the mounting bolts with a constant torque; if the tightening is uneven, the metal/I10 ring 30 may become lopsided, causing reactor water to leak from the seal portion 33. . Furthermore, if the screw is tightened or loosened with excessive torque, it may cause galling of the screw and cause serious trouble. Therefore, the tightening and loosening torques of the air motor 25 for attaching and detaching the mounting bolts are adjusted to several percent of the specified value, and the arrangement is such that the dispersion is eliminated.

As mentioned above, since it is necessary to arrange eight air motors for the eight mounting bolts, the space for arranging them in the attachment/detachment head is limited, making it difficult to handle the air hoses and signal cables. And the detachable head has a larger diameter,
9. A forest stands at the bottom of RPV. Interference with CR, D housing, neutron measurement/1 housing, and 1l-1, CRD and neutron measurement cables are duplicated in the pedestal room.
There are quite severe restrictions on the rotation of the rotation 1 attachment/detachment head 16 of the rotation attachment/detachment device 13 of the rotation movement device 11, the travel of the handling device 14, and the rollover, and a more compact equipment configuration is required.

The present invention is proposed in view of the drawbacks of the prior art. Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a detailed view of the CRD attachment/detachment head of the present invention. Detachable head 1
6 is an uncoupling mechanism 35 for the control rod (not shown) and the CRD 6, an uncoupling detection mechanism 36, a CRD attachment/detachment mechanism 37, a drain processing mechanism 38, and a head rotation mechanism 39.
, a buffer mechanism 40 and a load detection mechanism 41.

FIG. 3 shows a state in which the CRD 6 to be replaced and the detachable head 16 are accurately positioned. The positioning is performed by rotating 0 of the turning movement device 11 and traveling R of the attaching/detaching device 13.
This is done by aligning the screw 42 on the outer periphery of the CRD housing and the cap nut 43 of the attachment/detachment head 16 under -0 control. Aligning the conventional hexagonal wrench and hexagonal hole, as well as positioning and fitting 8 at the same time, with one cap nut 4
Only the positioning required in step 3 is required, and the alignment accuracy was previously only within 1 mm, but with this method, the screw of the cap nut is structured to be easy to fit, such as an Edison screw. In addition, if the lower surface of the cap nut 43 is made spherical and configured to be self-centering, screwing and fitting is possible even if the position is shifted by several degrees.

Since the cap nut 43 is supported by the coupling pin 44 and the compression spring 451 at the upper part of the attachment/detachment head 16, even if the tip of the cap nut 43 collides with the CRD housing 4, this compression spring 45 will prevent the cap nut 43 from colliding with the CRD housing 4. This buffer prevents impact force from being applied to the 5 attachment/detachment head 16 side. By making the hole 46 of the cap nut 43 and the coupling pin 44 sufficiently spacious, a numerical positioning error can be tolerated.

(The attachment/detachment of the 4D is performed by rotating the air motor 47 using a pinion 49 that is fixed integrally with the output shaft 48 of the air motor.
, meshes with the gear 50 and rotates a disk 51 that is fixed integrally with the gear 50 .

A coupling bottle 44 is connected to the compression spring 4 on the disk 51.
5, and is fitted into a hole 46 provided in the cap nut 43. Therefore, the rotational force of the air motor 47 rotates the cap nut 43, which engages with the screw 42 formed on the outer periphery of the CRD housing and connects CR and D6 to the CRD.
By tightening the pressure onto the seat surface of the RD housing 4, the installation of the JD is completed.

The pressing force between the CRD housing 4 and the CRD seat surface 29 is
In order to keep the load below a specified level and to fully alleviate the impact force upon collision, a spring 52 is built into the detachable head 16 to prevent overload from being applied to the elevating mechanism. Then, in order to stop the lifting air motor at the specified load,
All load detectors 53 are built-in. This may cause damage to the CRD housing sheet or the rack of the lifting drive unit.
It is constructed so as not to adversely affect mechanical parts such as pinions.

When removing or installing a CRD, the drain of reactor water that scatters from the seat surface to the surrounding area can be removed by stopping the drain sleeve and seal ring, which are raised and lowered by conventional air cylinder operation.
The RD attachment/detachment cap nut 43 also serves as the RD attachment/detachment nut 43. Traditionally, high-dose initial drainage when removing a CRD has been performed using mountain drains.
? Loosen it halfway and pull out the CRD6 downwards for about 10 steps to eject it. In the attachment/detachment head of the present invention, the cap nut 43
Even if the cap nut 43 is loosened and the CRD is lowered by about 6klOmm, the screw part is extended to provide some extra space.The structure is such that even if the cap nut 43 is loosened and the CRD is lowered by about 6klOmm, it will not leak to the outside and scatter. The structure is such that the water is passed through the drain pipe at the bottom of the attachment/detachment device, and then led to the drain pit at the bottom of the RPV pedestal. 55 is a guide.

The control rod and CRD uncoupling mechanism 35 and uncoupling detection mechanism are operated by raising and lowering a piston by operating an air cylinder, as in the past.

〔Effect of the invention〕

According to the present invention, the CRD can be attached and detached by tightening one nut.
This was made possible by loosening the operation. This eliminates the need for attaching and detaching a large number of mounting bolts, which was conventional, and makes it easier for the operator to visually confirm the final alignment. Moreover, since there is only one attachment/detachment nut, the external shape of the attachment/detachment head is compact, and there is less need to check for interference with other equipment when operating inside the pedestal.

With the above features, the total conversion time for CRD9 conversion is approximately 1
72, and by reducing the time required for workers to enter the area for visual confirmation, their exposure dose can be reduced to about 1/3. Furthermore, since the number of rotating devices such as air motors can be reduced, the maintenance period thereof can also be significantly reduced.

[Brief explanation of drawings]

Figure 1 is C) Overall schematic diagram of the LD exchange device, Figure 2 is:
FIG. 3 is an elevational sectional view of a conventional CRD attachment/detachment head, and FIG. 3 is an elevational sectional view of a CRD attachment/detachment head of the present invention. 1...Reactor pressure vessel, 2...Reactor containment vessel%3
...Pedestal, 4...CRD nousing, 6.
...CB, D. 11... Rotating movement device, 12... CRD exchange device,
13... CR, D attachment/detaching device, 14... CRD handling device, 16... attachment/detachment head, 22... CRD mounting bolt, 23... hexagonal hole, 24... bolt wrench, 28...・Head rotation mechanism, 29... Seat surface, 30... Metal O-ring, 31... Drain processing mechanism, 32... Air cylinder, 33... Drain sleeve, 34... Seal ring, 35 ...Uncoupling mechanism 1.36...Uncoupling detection mechanism,
37... CB, D attachment/detachment mechanism, 38... Drain processing mechanism, 39... Head rotation mechanism, 40... Buffer mechanism, 41... Load detection mechanism, 42... Screw, 43...
・Fukuro nut, 44... Coupling pin, 45...
Compression spring, 47 Air motor, 48... Output shaft, 49.
... Binion, 50 ... Gear, 51 ... Continued from page 1

Claims (1)

[Claims] (1) A rotating carriage that horizontally rotates on an annular rotating rail provided on a bracket protruding from the wall of the pedestal chamber at the bottom of the reactor pressure vessel, and a first traveling carriage that moves on the rotating carriage. a CRD attaching/detaching device for attaching and detaching a control rod drive mechanism (hereinafter referred to as CR, D) to the reactor pressure vessel; Deliver and receive the CRD to the attachment/detachment device, and then roll over onto the held CRD'.
In a CRD exchange device consisting of a D handling device, the CR
CRD installation and removal using the D attachment/detachment device is performed by a cap nut method without using mounting bolts, and the cap nut is supported by an elastic body and rotated by a motor for tightening. The water drain receiver is configured to be used for all purposes, and is equipped with a buffer and overload detector in case of collision with the CR and D housings when the attachment/detachment device is raised, and the CRD tightening means is a single function to equalize the pressure of the seat. A control rod drive mechanism exchange device characterized in that it is provided with a means for pressing.・