JPS58213298A - Nuclear fuel channel removable machine - 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 The present invention provides a nuclear fuel assembly that is attached to the inner wall of a nuclear reactor spent fuel storage pool and used for inspecting fuel bundles and for attaching and detaching fuel bundles and channel boxes. Regarding the channel attachment/detachment machine.

Reactor nuclear fuel is usually inserted into many pipes, and the many pipes are bundled into a prismatic fuel bundle.
The fuel bundle is covered with a rectangular channel box. Then, depending on a predetermined burnup within the reactor core, shuffling within the reactor core or replacement with new fuel is performed. Additionally, the fuel bundle is visually inspected periodically to confirm its soundness and determine whether it is ready for rebarking.

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

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 in a vertically movable manner, is connected to the cart 2 at both ends, and supports the sprockets and sprockets of the drive mechanism 3 attached to the operation console 4. The elevating position of the cart 2 is maintained by a chain 8 that is hung around an idler sedge rocket 7 provided at the lower end of the main body frame. The cart 2 is substantially integrally formed with 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. 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 above-mentioned work is performed manually or remotely from the fuel exchange floor 6 and the operation console 4.

Normally, visual inspection of the fuel bundle must be performed over the entire length of the fuel bundle, but with conventional equipment, the upper guide 10 shown in FIG. However, there is a drawback that the upper guide cannot be rotated. Furthermore, although the vertical position of the cart 2 is detected by a 7-year-old encoder, etc., it is not possible to determine the elongation of the fuel assembly or other factors.

Furthermore, when loading spent fuel onto a loading/unloading machine, water shielding regulations prevent it from being delivered above the water surface, so even when handing over new fuel, the auxiliary hooks of overhead cranes or fuel exchange machines must be submerged in the water. However, there are still problems with radioactive decontamination, and improvements are required from the perspective of radioactive decontamination.

It is an object of the present invention that the upper guide part of the channel attachment/detachment machine can be remotely moved up and down and rotated at any position on the cart in order to inspect the fuel bundle. In addition, a scale is installed on the lifting cart to measure the elongation of the fuel bundle, and to change the delivery position of new fuel and spent fuel by remote control, which saves labor, improves work efficiency, and reduces radiation exposure. to give.

An embodiment of the present invention is shown in FIGS. 2 to 9 below. Second
The figure shows an overview of the cart 2.

The cart 2 is composed of a lower support 11 that receives the weight of the fuel assembly 9, and an upper guide 10 that supports the fuel assembly in an upright manner without tipping over, and these are substantially integrally formed. ing.

Conventionally, the fuel bundle hidden behind the upper guide 1o could not be visually inspected, but by making the cart frame 12 into a divided structure as shown in the figure and rotating the screw shaft 13 with the handling tool 14, a screw-nut mechanism can be installed. As a result, the cart frame 15 integrally formed with the upper guide 1o is raised and lowered, making it possible to inspect the fuel bundle portion hidden behind the upper guide 10. Further, the support 35 is provided to temporarily prevent the fuel bundle from falling when the upper guide 1o is raised or lowered. This support preferably holds the upper tie plate or channel spacer portion of the fuel bundle. Also, when the cart is being raised or lowered, it is swingably mounted in a position that does not interfere with the cart.

3 and 4 show the detailed structure of the cart 2. FIG. The upper guide 1o is composed of a fuel guide section 16 and a rotation mechanism X17, and rotates the shaft 18 by rotating the shaft 18.
The pinion 2o, which is slidably incorporated through the guide roller 19, rotates.

Then, the large gear 22 is rotated via the gear 21, and the entire circumference of the fuel bundle, which is supported by the lower support 11 and prevented from falling over by the upper guide IO, is visually inspected.

The shaft 18 extends upwardly to form the rotating handle shaft shown in FIG. As a result, it is possible to rotate the cart 2 at any vertical position, and furthermore, this shaft 18 can be driven by a drive motor, which is fixed to the upper control table 4 and can be operated manually or remotely. . 23 is a plate killing ring that stops the upper guide at any rotational position; 24
25 is a brake pad, and 25 is a manual handle.

6 to 8 show an overall view of the attachment/detachment machine of the present invention. Conventionally, the lifting position of the cart 2 is indicated by a signal from a shaft encoder provided in the drive mechanism, but the length of the fuel bundle or Currently, it is not possible to measure changes in dimensions such as fuel rod spacing, etc., so 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. This makes it possible to measure dimensions. The horizontal scale 26 is attached to a swingably operable support 29 to 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. The spacing between each pipe in the fuel bundle or
Only when measuring the width of the channel box, the support 29 is swung in the direction of the arrow shown in FIG. 8, the cart is raised and lowered, and the lateral dimension of the fuel bundle or the channel box is measured.

Further, a vertical scale 27 is installed 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 has been delivered underwater using an overhead crane or an auxiliary hoist for a fuel exchanger, 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. 9th
In the figure, when handling spent fuel, it always automatically stops at the rising end 30 and rising end safety 31 positions, and even if there is a problem in which the rising end does not operate, the mechanical stopper 3
Stop at 2. When handling new fuel, the mechanical stopper is removed and a key switch is operated to allow the fuel pail 33 to rise above the pool water surface 34.

Therefore, when handling spent fuel, use the mechanical stopper 3.
2 and the key switch are interlocked so that the rising end 3o cannot be cleared unless the key switch is operated. This allows t
This prevents radiation exposure for food handling workers and improves safety and work efficiency.

According to the present invention, since the guide mechanism that supports the fuel body can be moved up and down, the entire length of the fuel bundle can be visually inspected.
In addition, the guide mechanism can be used remotely (
Because it can be rotated (automatically or manually), inspections that previously required several people can now be performed by just one person.

In addition, in order to measure changes in the fuel bundle over time, scales were installed on the main body of the attachment/detachment machine and on the cart frame for easy visual inspection.

Furthermore, we have discontinued the underwater delivery of new fuel to the loading/unloading machine body using the conventional overhead crane or fuel changer, and installed an interlock to allow underwater delivery only when handling spent fuel. This has made it unnecessary to decontaminate overhead cranes and other underwater equipment when new fuel is delivered.

[Brief explanation of the drawing]

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 the cart, and Figure 4 is A-At@ of Figure 3. Fig. 5 is a detailed view of the guide rotating handle, Fig. 6 is a front view of the entire attachment/detachment, Fig. 7 is a side view of Fig. 6, and Fig. 8 is a view of A-A in Fig. 6. The A arrow view and FIG. 9 are diagrams showing the cart lifting and lowering positions. ■・・・Detachable unit main body, 2...Cart, 3...Drive mechanism, 4...Operation console, 5...Spent fuel pool, 6...
・・Fuel exchange floor-17・Sprocket, 8・・
・Cheno, 9... Fuel assembly, IO... Upper guide, 11... Lower sabot-1, 12... Cart frame, 13... Screw shaft, 14... Handling tool, 15. ... Cart frame, 16... Fuel guide section, 17... Rotating mechanism, 18... Shaft, 19... Guide roller, 20
... Binion, 21... Gear, 22... Large gear,
23...Brake ring, 24...Brake pad, 25...Manual handle, 26...Horizontal scale, 2
7... Vertical scale, 28... Bracket, 29...
・Support, 30...Rising i'J, 31...Rising end safety, 32...Mechanical stopper, 33...Fuel relief 60

Claims (1)

[Claims] 1. A fuel body consisting of a fuel bundle made up of a large number of nuclear fuels and a removable channel box that covers the fuel/kundle can be raised and lowered into a spent fuel storage pool. In the nuclear fuel channel shoulder release method having a lower support supporting the fuel assembly to receive its own weight and a guide for standing the fuel assembly upright, (1) the guide supporting the fuel assembly upright is movable up and down;
(2) The guide is rotatable at any position, and (3) a fuel body elevating table (hereinafter referred to as a cart) that integrates the lower support and the guide, and a fuel body measuring scale are provided on the main body frame. , (4) A nuclear fuel channel attachment/detachment machine that allows new fuel to be transferred above the water surface of the storage pool.