JPS5841998B2 - Nuclear fuel gripping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear fuel grabbing device, and more particularly to a nuclear fuel grabbing device such as a fuel assembly in a nuclear power plant.

A conventional nuclear fuel grasping device will be explained with reference to FIG.

The nuclear fuel grasping device includes hoist drums 1 and 2, fixed sheaves 3 and 4, a first rope 5, a second rope 6, an elastic tube 9,
It mainly consists of a fuel grabber 10.

In this case, in the telescopic tube 9, tubes B, C, D, and E of smaller diameter are slidably attached to the first tube A having the largest diameter in this order.

At the center of the upper surface of the fifth pipe E having the smallest diameter, there is a first rope 5.
The tip of the fuel gripper 1 is locked, and the fuel gripper 1 is placed at an eccentric position on the T plane.
0 (hereinafter simply referred to as a gripping tool) is rotatably engaged.

The tip of the second rope 6 is locked to the upper end of the gripping tool 10.

Further, the telescopic tube 9 is rotatable by a rotating device 13 that transmits rotational force to the maximum diameter tube A via a pin 12.

Therefore, when replacing the fuel assembly 11 disposed in the core of a nuclear reactor, the present device moves above a predetermined fuel assembly 11.

Next, as the hoist drums 1 and 2 rotate and the first and second ropes 5.6 are let out, the gripper 10 and the telescopic tube 9 are lowered.

The gripper 10 is rotated so that it can grip the upper end of the fuel assembly 11.

This rotation is caused by the rotating device 13 transmitting a rotational force to the maximum diameter tube A through the pin 12, thereby rotating the telescopic tube 9 and transmitting it to the gripping tool 10 through the rotational engagement portion.

When the fuel assembly 11 is grabbed, the hoist drum 1.degree. 2 is reversely rotated and the first and second ropes 5, 6 are hoisted up.

At this time, the telescopic tube 9 rotates around the first rope 5, and the second rope 6 turns on the circumference around the first rope 5, so that the nuclear fuel can be exchanged. It can be performed smoothly and accurately.

When the first and second ropes 5 and 6 are wound up as specified, the telescopic tube 9 stores the other tubes B, C, D, and E inside the largest diameter tube A, as shown in FIG. Fuel assembly 11
is raised.

However, during the expansion and contraction of the telescopic tube 9, there is a possibility that foreign matter may enter between adjacent tubes.For example, if the telescopic tube 9 is in the most contracted state as shown in Since A (which is assumed to be the first pipe) is suspended by the pin 12 at the upper part, the weight of the pipe BE acts on the first rope 5.

Next, when this rope 5 is let out, the tubes B to E descend, and the inner circumference of the first tube A and the outer circumference of the second tube B slide.

When descending further, the second pipe B is stopped by the stopper part S and the weight of the second pipe B is supported by the first pipe A, so the load on the rope 5 is equal to the weight of the pipe C-E. becomes.

However, if a foreign object is present between the first tube A and the second tube B when the telescopic tube 9 is lowered, the sliding action will not be performed smoothly, and the second tube B will not reach the stopper section. If the third pipe C is stopped by the stopper part of the second pipe before the third pipe C has descended to the bottom, the load on the rope 5 is not the weight of the pipe E, but the entire weight of the pipes B and C. Some of it will be added.

Moreover, if foreign matter is removed during the work, there is a risk that the load will increase shockingly.

An object of the present invention is to solve the drawbacks of the above-mentioned techniques and provide a nuclear fuel gripping device with high safety by providing a monitoring mechanism for safely lifting and lowering a fuel assembly. be.

For this purpose, the present invention stores the moving range of the telescopic pipe and the lifting load value of the rope in this range in advance in a storage device, and compares the actually detected position and load value with a comparison device, The present invention is characterized in that a hoisting device operation permission signal is generated when the detected load value is within an allowable range.

The present invention will be described below with reference to an illustrated embodiment.

In FIGS. 1 and 2, load detection devices γ and 8 called load cells are attached to the ends of fixed sheaves 3 and 4, respectively, and there is no difference in structure from the conventional nuclear fuel gripping device.

In FIG. 3, the monitoring mechanism that characterizes the present invention includes the load detection devices 1 and 8, the position detection device 13, and the storage device 14.
, a comparator 15, a logic circuit 16, and the like.

The moving range of the contracting tube and the lifting load value of the rope in this moving range are input into the device 14 in advance.

The position detection device 13 is a well-known device that detects the rope payout position, that is, the movement range of the telescopic tube, based on the rotation angle of a sheave or hoist drum, for example, and the load detection devices 1 and 8 are A strain gauge may be provided at the shaft end of a fixed sheave, but a strain gauge may also be attached to the rope.
A torsion make may be interposed between the hoist shaft and the morph.

The comparison device 15 is also called a comparison circuit, and receives the movement range stored in the storage device 14 and the load value in that range, as well as the outputs of the position and load detection devices 13, 7.8.

Then, these input values are compared and the logic circuit 16
When the detected load value is within a permissible range, a hoist drum hoisting permission signal is generated via the hoist drum.

With the above configuration, the abnormality of the expansion tube can be determined and the rope 5
This is extremely useful as a safety measure because it can stop the descent of the vehicle.

According to the present invention, it is possible to monitor not only the abnormality of the telescopic pipe but also the load applied to the rope 6, that is, the abnormality of the gripping tool 10.

According to the present invention, safety can be improved in nuclear fuel grabbing work.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 shows the telescopic tube when it is at its maximum extension, FIG. 2 is a configuration diagram showing the telescoping pipe when it is at its maximum contraction, and FIG. FIG. 2 is a block diagram of a monitoring mechanism used in the embodiment. 7.8...Load detection device, 13...Position detection device, 14...Storage device, 15...
...Comparison circuit, 16...Logic circuit.

Claims (1)

[Claims] 1. In a nuclear fuel grasping device having a telescopic pipe that can be moved up and down and a rope for hanging the telescopic pipe, a storage device that stores in advance the movement range of the telescopic pipe and the lifting load value of the rope in this range; A position detection device that detects the expansion/contraction position of the telescopic pipe, a load detection device that detects the lifting load of the rope, and signals from these detection devices are respectively inputted, and the values stored in the storage device at each telescopic pipe position are inputted. A comparison position where the lifting load value of the rope in the movement range of the pipe is compared with the load value detected by the load detection device and the telescopic pipe position detected by the position detection device, and when the detected load value is within the allowable range. 1. A nuclear fuel gripping device comprising a fuel gripping device hoisting device operation permission signal generating means for generating a signal.