JPS6113198B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control rod drive device replacement device, and particularly to uncoupling (uncoupling) between a CRD and a control rod when a control rod drive device (hereinafter referred to as CRD) is removed. CRD replacement work is carried out during regular reactor inspections. This CRD replacement work is carried out in an atmosphere with a high radiation dose rate, so
In particular, it is being studied to reduce radiation exposure for workers.

An object of the present invention is to provide a CRD replacement device that can reduce radiation exposure to workers and save labor.

The CRD replacement device of the present invention is (a) housed in a CRD attachment/detachment head, installed to engage with the lower end of the CRD piston tube, and configured to move up and down for pushing up the piston tube when replacing (pulling out) the CRD. In a CRD exchange device including a CRD anchor spring mechanism having a movable pipe and an adapter provided at the tip of the pipe, (b) a CRD lifting/lowering drive mechanism, and (c) a CRD attaching/detaching device, the shape of the adapter is set to the piston tube. The device is characterized by having a recessed portion in the center so that the lower end of the device can be inserted.

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

In FIG. 1, a reactor pressure vessel 1 is installed on a pedestal 3 located within a containment vessel 2 (hereinafter abbreviated as PCV). A CRD housing 4 and a neutron flux measurement housing 5 are provided protruding from the lower part of the reactor pressure vessel 1, forming a part of the reactor pressure vessel. The CRD 6 is housed within the CRD housing 4. A space 7 is formed within the pedestal 3 below the reactor pressure vessel 1 . CRD6
A loading/unloading port 8 is provided in the pedestal 3 for loading and unloading items into and out of the space 7. A bracket 9 is provided protruding from the side wall of the pedestal 3 within the space 7. An annular rail 10 is installed above the bracket 9. A turning movement device 11 moves on a rail 10. The CRD exchange device 12 includes a turning movement device 11,
It is composed of a CRD attachment/detachment device 13 and a CRD handling device 14. The CRD attachment/detachment device 13 is connected to the traveling bogie 1
5. Consists of a detachable head 16, which has functions such as attaching and detaching the CRD mounting bolt, anchoring the control rod and CRD, checking the anchor spring, draining, and raising and lowering the detachable head.
The CRD 6 can be attached to and removed from the housing 4. The CRD handling device 14 is composed of a traveling trolley 17 and a mast 18, and is used to receive and deliver the CRD 6 removed by the CRD attachment/detachment device 13.
It has the rollover function of CRD6. The CRD 6 overturned by the CRD handling device 14 is held and loaded on a CRD transport cart 21 that is removably attached to the mast 18, and is transported from the loading/unloading port 8 of the pedestal 2.
Through-hole 2 of reactor containment vessel 2 via bridge 19
0 and is carried out. When installing CRD6, the procedure described above is reversed.

The CRD replacement procedure will be explained below.

Figure 1 shows the rotation movement device 11 and the CRD attachment/detachment device 1.
The figure shows a state in which the traveling carriage 15 of No. 3 is driven and the positioning of the detachable head 16 and the CRD 6 to be replaced has been completed. From this position, the elevating drive mechanism of the CRD attachment/detachment device 13 raises the attachment/detachment head 16.
Connect to the bottom of CRD6.

Figures 2 to 6 show a series of operations from removing the CRD to rolling over. FIG. 2 shows a state in which the detachable head 16 is connected to the lower part of the CRD 6. From this state, perform the function of the CRD attachment/detachment head 16, which is the uncoupling of the control rod and the CRD 6, check it, drain the water, remove the CRD mounting bolt, and remove the CRD 6 housed in the CRD housing 4. CRD6
The CRD attachment/detachment head 16 carrying the CRD is lowered. Next, the traveling cart 17 of the CRD handling device 14 is driven to move the CRD 6 from the attachment/detachment head 16 to the CRD handling device 1.
4 is delivered to the CRD transport cart 21 attached to the CRD transport cart 21.

FIG. 3 shows the CRD 6 being delivered to the CRD handling device 14. In this state CRD6
has not been completely pulled out from inside the CRD housing 4. After the CRD handling device 14 receives the CRD 6,
The CRD 6 is lowered to the position shown in FIG. 4 by the lifting mechanism of the CRD handling device 14, and the entire extraction is completed.

FIG. 4 shows the CRD 6 in its fully pulled out state.
After the CRD is delivered, the CRD attachment/detachment device 13 is moved back to the wall inside the pedestal 3, avoiding interference when the CRD is lowered or rolled over.

Next, as shown in FIG. 5, the CRD 6 is turned over at a predetermined angle by the overturning mechanism of the CRD handling device 14, and then turned to the position of the loading/unloading port 8 provided in the pedestal 3 by the turning movement device. CRD
When the positions of the loading and unloading entrances match, the mast 18 is further rolled over by the CRD handling device and brought to a horizontal position, as shown in FIG. 6, and the series of operations for removing the CRD is completed. Installation can be performed by reversing this removal procedure.

As mentioned above, the present invention provides the CRD mounting bolt attachment/detachment, the control rod/CRD anchoring spring, the checking of the anchoring spring, and the drain processing functions of the CRD attachment/detachment head 16, especially the control rod/CRD anchoring. This will be explained in detail below using the figures.

FIG. 7 shows that the CRD attachment/detachment head 16 is connected to the lifting shaft 22.
The figure shows the state where it is fixed to the CRD6, raised and connected to the bottom of the CRD6. From this state, the connection between the CRD 6 and the control rod 23 (FIG. 8) can be released, the CRD mounting bolt 47 can be removed, and the CRD 6 housed in the CRD housing 4 can be pulled out.

The procedure for uncoupling the CRD 6 and the control rod 23 will be described below.

In FIGS. 7 and 8, the outer tube 24 of the CRD 6 and the control rod 23 are connected by a coupling spud 25 and a coupling 26. As shown in FIGS. Thereby, the control rod 23 controls the nuclear reaction within the reactor by driving the outer tube 24 up and down. This CRD6 and control rod 23
The uncoupling is performed by pushing up the uncoupling rod 27. Now, the 7th
By applying air pressure to the piston lower chamber 30 shown in the figure, the adapter 33 is pushed up through the pipe 31 and the nut 32, and the lower end 35 of the piston tube 34 is pushed up. By pushing up the lower end 35 of the piston tube 34 by a predetermined amount, the uncoupling rod 27 pushes up the spacer 28 against the force of the compression spring 29. As a result, the coupling spud 25 contracts due to its spring action, and the withdrawal operation of the CRD 6 (performed by the hydraulic unit) lowers the outer tube 24 by a distance "L", completing the uncoupling of the CRD and control rod.

SUMMARY OF THE INVENTION An object of the present invention is to provide a CRD exchange device that can always reliably stop and hold a CRD at a predetermined position (set position).

FIG. 10 shows the state in which the CRD 6 is connected to the CRD attachment/detachment head 16. That is, as shown in FIG. 10, in order to accurately limit the amount by which the piston tube 34 is pushed up, the shape of the adapter 33 is provided with a recess D in the center so that the lower end 35 of the piston tube 34 can be inserted. Even if the piston tube 34 is longer than the reference length (protrudes), the protrusion is absorbed by inserting the lower end 35 of the piston tube 34 into the recess D. be.

In addition, in the present invention, the CRD lower shape is
It is characterized in that the attachment/detachment head 16 and the CRD 6 are connected in horizontal plane contact.

In the present invention, it is housed in the CRD attachment/detachment head 16 and installed so as to engage with the lower end 35 of the piston tube 34 of the CRD, and is movable up and down to push up the piston tube 34 when replacing the CRD (during removal). An anchor spring mechanism 50 having a pipe 31 and an adapter 33 provided at the tip of the pipe includes a pipe 31, a nut 32,
It is composed of an adapter 33, a piston 51, etc. Applying air pressure to the piston lower chamber 30,
The adapter 33 having the recess D provided at the tip of the anchor spring mechanism 50 pushes up the lower end 35 of the piston tube 34, thereby causing the eighth
Push up the uncoupling rod 27 shown in the figure to release the connection between the CRD 6 and the control rod 23.
The amount by which the piston tube is pushed up must be accurately limited because the dimensions of the engagement between the uncoupling spring spud 25 and the coupling ring 26 are delicate. 40
is a drain sleeve, 41 is a cylinder, and 42 is a seal ring.

Next, the engagement relationship during uncoupling will be explained with reference to FIG. 9. As shown in FIG. 8, the amount "1" of pushing up the piston tube 34 is the same as the amount of pushing up the uncoupling rod 27, and
The amount of descent of the outer tube 24 due to the pulling operation is L=A−1. At this position, insert the uncoupling detector 36 into the CRD and confirm that the uncoupling is performed. The insertion position of the uncoupling spring detector 36 is also affected by the amount of push-up of the piston tube, resulting in a detection error. or,
Conventionally, the connection between CRD 6 and CRD detachable head 16 was
Since this is done using the tapered portion 37 and seat 38 of the CRD, the stroke of the piston 30 may vary greatly, particularly due to tolerances in machining the tapered portion of the CRD. Therefore, in the present invention, in order to eliminate the influence of the above-mentioned tolerance on the stroke of the piston 30, by providing the recess D in the adapter 33, the dimension C=B-l is set, and the adapter 33 is
The piston 30 is pushed up until it hits the ring flange 39 at the bottom of the CRD.

Further, in the present invention, as shown in FIG. 10, the connection between the CRD 6 and the bolt house 45 of the detachable head 16 having the wrench 44 and the drain hole 46 may be made into horizontal surface contact (contact portion 48). The supporting point of the CRD 6 can be kept constant at all times, making uncoupling of the CRD 6 and control rod easy and reliable, and troubles caused by uncoupling detection errors can be avoided. This will contribute to reducing the radiation exposure of workers and shortening the periodic inspection period of nuclear power plants.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of the CRD replacement device of the present invention, FIGS. 2 to 6 are side views of the device for explaining the CRD replacement procedure, FIG. 7 is a vertical cross-sectional view of a conventional detachable head, and FIG. 9 is a cross-sectional view showing the state of connection between the CRD and the control rod, FIG. 9 is a cross-sectional view showing the uncoupled state of the CRD and the control rod, and FIG. 10 is a longitudinal cross-sectional view of the detachable head used in the present invention. 1...Reactor pressure vessel, 4...CRD housing, 6...CRD, 11...Swivel movement device, 12
...CRD exchange device, 13...CRD attachment/detachment device, 1
4...CRD handling device, 33...Adapter, 3
4...Piston tube, 35...Lower end of piston tube, 36...Uncouple spring detector, 45...Bolt house, 48...Contact part, 5
0...Anchor spring mechanism, 51...Piston, D...Recess of adapter.

Claims (1)

[Claims] 1 (a) A vertical movement device that is housed in the attachment/detachment head of the control rod drive device and is installed to engage with the lower end of the piston tube of the control rod drive device to push up the piston tube when replacing the control rod drive device. (b) a control rod drive lifting drive mechanism;
A control rod drive unit exchange device including a control rod drive unit attachment/detachment device, characterized in that the shape of the adapter is such that a recess is provided in the center so that the lower end of the piston tube can be inserted therein. .