JPH0315720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear fuel attachment/detachment machine that is attached to the inner wall of a nuclear reactor spent fuel storage pool and used to attach and detach a channel box from a fuel assembly in order to inspect the fuel bundle.

Nuclear fuel for a nuclear reactor is usually inserted into a large number of pipes, and the large number of pipes are bundled into a prismatic fuel bundle, and the fuel bundle is covered with a prismatic channel box. Then, depending on a predetermined burnup within the reactor core, shuffling or replacement with new fuel is performed within the reactor core. Further, the fuel bundle is periodically visually inspected to confirm its soundness and determine whether it can be reused.

During this visual inspection, it is necessary to remove the channel box covering the fuel bundle, and a channel attachment/detachment machine (hereinafter referred to as an attachment/detachment machine) is installed.
This attachment/detachment machine removes the channel box covering the fuel bundle.

FIG. 1 shows an overall schematic diagram of a conventional attachment/detachment machine. The attachment/detachment machine mainly includes a main body 1, a cart 2, a drive mechanism 3, and an operation table 4. The main body 1 is installed vertically along the side wall of the spent fuel pool 5, supports a cart 2 so as to be able to rise and fall, and is connected at both ends to the cart 2, and supports the sprocket and main body of the drive mechanism 3 attached to the operation console 4. The vertical position of the cart 2 is maintained by a chain 8 that is stretched around an idler sprocket 7 provided at the end of the cart 1. The cart 2 includes a lower support 11 that receives the weight of the fuel assembly 9 at the lower part, and an upper guide 10 that supports the fuel assembly so that it stands upright and does not fall over.
are substantially integrally formed. Then, the cart 2 holding the fuel assembly 9 is raised and lowered, the channel box is removed, and the fuel bundle is inspected. The aforementioned operations are performed manually or remotely from the fuel exchange floor 6 and operation console 4.

In addition, it is necessary to visually inspect the front circumference of the fuel bundle held by the cart 2, and for this purpose it is necessary to rotate the fuel bundle.
The nuclear fuel attachment/detachment machine described in Publication No. 130698 is Cart 2.
The upper guide 10 has a rotation mechanism that rotates the upper guide 10 at any vertical position, and has a structure that facilitates visual inspection.

However, visual inspection of the fuel bundle must be performed not only around the entire circumference of the fuel bundle but also over its entire length, and the conventional apparatus shown in FIG.
The conventional device described in Japanese Patent No. 130698 has the disadvantage that the back side of the upper guide 10 shown in FIG. 1 is hidden and cannot be visually inspected. In addition, the vertical position of the cart 2 is detected by a shaft encoder, etc.
Another disadvantage is that dimensional changes such as elongation of the fuel bundle cannot be measured. Furthermore, when loading spent fuel onto a loading/unloading machine, it cannot be delivered above the water surface due to water shielding regulations, so even when handing over new fuel, the auxiliary hooks of the overhead crane or fuel changing machine must be submerged in the water. There were problems with radioactive decontamination, and improvements were required from the perspective of radioactive decontamination.

A first object of the present invention is to provide a nuclear fuel channel attachment/detachment machine that allows visual inspection of a fuel bundle to be easily performed over the entire length and circumference of the fuel bundle.

A second object of the present invention is to provide a nuclear fuel channel attachment/detachment machine that can easily visually inspect a fuel bundle over the entire length and circumference of the fuel bundle, and can measure changes in dimensions such as elongation of the fuel bundle. It is.

A third object of the present invention is to facilitate visual inspection of the fuel bundle over the entire length and circumference of the fuel bundle, and to eliminate the need for decontamination of overhead cranes and other fuel handling equipment when delivering new fuel. The purpose of the present invention is to provide a nuclear fuel channel attachment/detachment machine.

The first purpose is to connect the lower support and the upper guide of the fuel body lifting truck, and to divide the cart frame into a first cart frame integrated with the lower support and a second cart frame integrated with the upper guide. a cart frame structure; a moving means for raising and lowering the second cart frame relative to the first cart frame to independently move the upper guide;
This is achieved by providing a rotating means for rotating the upper guide.

The second object is further achieved by providing a fuel body measuring scale on the fuel body lifting cart and the nuclear fuel channel attachment/detachment machine body.

The third object is further achieved by configuring the storage pool so that new fuel can be delivered on the water surface of the storage pool.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 9. FIG. 2 shows an overall outline of the cart 2. The cart 2 includes a lower support 11 that receives the weight of the fuel assembly 9, and an upper guide 10 that supports the fuel assembly so that it stands upright and does not fall over. connected together. The cart frame 12 is integrally constructed with the lower support, and the cart frame 15 is integrally constructed with the upper guide 10. A threaded shaft 13 is inserted through the cart frame 15 so as to be rotatable but prevented from moving in the axial direction, and a lower portion of the threaded shaft 13 is screwed into a nut portion of the cart frame 12. Further, the upper end of the screw shaft 13 is connected to a handling tool 14.
In this screw-nut mechanism, by rotating the screw shaft 13 with the handling tool 14, the cart frame 15 integrated with the upper guide 10 moves up and down with respect to the cart frame 12, and the upper guide 10 moves independently. By remotely moving the upper guide up and down in this way, the upper guide 10
It is now possible to visually inspect parts of the fuel bundle that could not be done due to the shadow.

Furthermore, a support 35 is provided to temporarily prevent the fuel bundle from falling over when the upper guide 10 is raised or lowered. This support preferably holds the upper tie plate or channel spacer portion of the fuel bundle. In addition, when raising and lowering the cart, it is possible to retreat to a position that does not interfere with the cart.
It is mounted so that it can swing freely.

3 and 4 show the detailed structure of the cart 2. FIG. The upper guide 10 is composed of a fuel guide section 16 and a rotation mechanism 17, and by rotationally driving a shaft 18, a pinion 20 slidably incorporated in the shaft 18 and a guide roller 19 rotates.
Then, by rotating the large gear 22 via the gear 21,
The entire circumference of the fuel bundle, which is supported by the lower support 11 and prevented from falling by the upper guide 10, is visually inspected. The shaft 18 extends upwardly to form the rotating handle shaft shown in FIG. As a result, the fuel guide section 16 and the fuel bundle supported thereon can be rotationally driven at any vertical position of the cart 2, and furthermore, this shaft 18 can be driven by an electric motor, and the upper control panel 4 and can be operated manually or remotely. 23 is a brake ring that stops the upper guide at any rotational position; 2
4 is a brake pad, and 25 is a manual handle.

6 to 8 show general views of the attachment/detachment machine of the present invention. Conventionally, the vertical position of the cart 2 is indicated by a signal from a shaft encoder provided in the drive mechanism, but at present it is not possible to measure changes in dimensions such as the length of the fuel bundle or the spacing between fuel rods. For this reason, as shown in the figure, a horizontal scale 26 is provided on the fixed side of the attachment/detachment machine body 1, and a vertical scale 27 is provided on the cart 2, thereby making it possible to measure the dimensions of the fuel bundle. The horizontal scale 26 is attached to a swingably operable support 29 on a bracket 28 of the attachment/detachment machine main body 1, and is normally held along the side wall of the spent fuel pool 5. Only when measuring the spacing between the pipes of the fuel bundle or the width of the channel box, swing the support 29 in the direction of the arrow shown in Figure 8 to raise and lower the cart, and measure the lateral dimension of the fuel bundle or channel box. Measure.

Further, a vertical scale 27 is attached in the longitudinal direction of the cart 2, and is used to compare and measure elongation, distortion, etc. of the fuel bundle due to loading into the reactor core.

FIG. 9 shows the position of the fuel bundle as the cart 2 is raised and lowered. Conventionally, new fuel is delivered underwater using an overhead crane or an auxiliary hoist of a refueling machine, similar to the handling of spent fuel. In the present invention, only the delivery of new fuel can be carried out on the surface of the pool, thereby improving the decontamination problem and operability of each hook.

That is, in FIG. 9, when handling spent fuel, the rising end 30 of the fuel is in the rising end safety position 3.
The limit switch operates at 1 and automatically stops at all times, and even if there is a problem in which the limit switch does not operate at position 31, it will stop at position 32 using a mechanical stopper. In addition, the mechanical stopper can be opened, and when handling new fuel, remove the mechanical stopper, operate the key switch,
The fuel bail 33 is configured to extend above the pool water surface 34. That is, the delivery position between new fuel and spent fuel can be changed by remote control.

Therefore, when handling spent fuel, an interlock is provided so that the rising end 30 cannot be cleared unless the mechanical stopper and key switch are operated. This prevents fuel handling workers from being exposed to radiation and improves safety and work efficiency. In addition, when handling new fuel, the new fuel can be delivered above the water surface of the storage pool, so auxiliary hooks such as overhead cranes or fuel changers are not submerged, and there is no need to decontaminate fuel handling equipment, resulting in labor savings. can be achieved.

As described above, according to the present invention, the upper guide supporting the fuel body of the cart can be moved independently, so the entire length of the fuel bundle can be visually inspected, and the upper guide can be rotated at any position as the cart is raised and lowered. It is also possible to visually inspect the entire circumference of the fuel bundle, and what previously required several people to perform a visual inspection can now be done by just one person.

In addition, since scales were attached to the main body of the attachment/detachment machine and the cart, it is possible to easily measure the aging of the fuel bundle by visual inspection.

Furthermore, we have stopped the underwater delivery of new fuel to the loading/unloading machine body using a conventional overhead crane or fuel changer, and have made it possible to do so above the water surface of the storage pool. This eliminates the need for decontamination of other fuel handling equipment, resulting in labor savings.

[Brief explanation of drawings]

Figure 1 is an overall schematic diagram of a conventional attachment/detachment machine, Figure 2 is an overall outline diagram of a cart, Figure 3 is a front view of a cart,
Figure 4 is a sectional view taken along line A-A in Figure 3, Figure 5 is a detailed view of the guide rotation handle, Figure 6 is an overall front view of the attachment/detachment machine, Figure 7 is a side view of Figure 6, and Figure 8. 6 is a view taken along the line A-A in FIG. 6, and FIG. 9 is a cart elevation position relationship diagram. Explanation of symbols, 1... Detachable machine body 2... Cart,
5...Spent fuel pool, 9...Fuel assembly, 1
0... Upper guide, 11... Lower support, 12
... Cart frame, 13 ... Screw shaft (transfer means), 14 ... Handling tool (same), 15 ... Cart frame, 17 ... Rotation mechanism (rotation means), 26 ...
Horizontal scale, 27... Vertical scale, 30... Rising end, 31... Rising end safety position, 32... Stop position by mechanical stopper, 33... Fuel bail, 34... Pool water surface.

Claims (1)

[Scope of Claims] 1. A nuclear fuel channel attachment/detachment machine body installed in a spent fuel storage pool, and a fuel body lifting truck that holds a fuel body and moves along the body,
The fuel body lifting truck connects the lower support and the upper guide of the fuel body lifting truck in a nuclear fuel channel attachment/detachment machine having a lower support that receives the weight of the fuel body and an upper guide for standing the fuel body upright, and the first integrated in the lower support.
a cart frame structure divided into a cart frame and a second cart frame integrated with the upper guide, and the second cart frame is raised and lowered with respect to the first cart frame to independently move the upper guide. A nuclear fuel channel attachment/detachment machine comprising: a moving means for rotating the upper guide; and a rotating means for rotating the upper guide. 2. Comprising a nuclear fuel channel attachment/detachment machine body installed in a spent fuel storage pool, and a fuel body lifting truck that holds a fuel body and moves along the body,
The fuel body lifting truck connects the lower support and the upper guide of the fuel body lifting truck in a nuclear fuel channel attachment/detachment machine having a lower support that receives the weight of the fuel body and an upper guide for standing the fuel body upright, and the first integrated in the lower support.
a cart frame structure divided into a cart frame and a second cart frame integrated with the upper guide, and the second cart frame is raised and lowered with respect to the first cart frame to independently move the upper guide. and a rotation means for rotating the upper guide, and a scale for measuring the fuel body is provided on the fuel body lifting cart and the nuclear fuel channel attachment/detachment machine body. Machine. 3. A nuclear fuel channel attachment/detachment machine body installed in a spent fuel storage pool, and a fuel body lifting cart that holds a fuel body and moves along the body,
The fuel body lifting truck connects the lower support and the upper guide of the fuel body lifting truck in a nuclear fuel channel attachment/detachment machine having a lower support that receives the weight of the fuel body and an upper guide for standing the fuel body upright, and the first integrated in the lower support.
a cart frame structure divided into a cart frame and a second cart frame integrated with the upper guide, and the second cart frame is raised and lowered with respect to the first cart frame to independently move the upper guide. 1. A nuclear fuel channel attachment/detachment machine comprising: a moving means for rotating the upper guide; and a rotating means for rotating the upper guide;