JP2964756B2 - Forced folding device for pantograph mechanism of refueling machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced folding device for forcibly folding a pantograph mechanism for positioning a gripper in a nuclear reactor refueling machine.

[0002]

2. Description of the Related Art In a nuclear reactor such as a high-temperature gas reactor or a fast breeder reactor in which refueling is performed without opening a pressure vessel, a reactor containment vessel top cover is removed while the reactor is stopped, and a refueling machine is connected to the pressure vessel. This is done through a standpipe provided on the upper mirror of this pressure vessel. The refueling machine grasps fuel with a gripper, supports the gripper and supports it with a link via an arm, lifts or suspends with a wire rope, and moves the fuel up and down a standpipe. In order to exchange fuel around the part other than immediately below the nozzle, it is necessary to incorporate a pantograph mechanism that offsets the gripper in the horizontal direction and perform automatic positioning by remote control from outside the furnace.

FIG. 6 is a configuration diagram of a pantograph mechanism of a conventional fuel exchanger. The refueling machine has a plurality of arms 1a,
A pantograph 1 mechanism composed of 1b and 1c, a ball screw 12 and a ball nut 12a supporting the pantograph mechanism 1, and a casing 2 supporting the ball screw 12;
And a built-in drive mechanism 5 located at the upper end of the ball screw 12. One end of the arm 1a is fixed to the fixed end 3 of the casing 2, and the other end is connected to a connection end 3a with the arm 1b. The arm 1b has one end connected to the drive end 4 of the ball nut 12a and the other end 6 connected to the storage box 8. When the built-in drive mechanism 5 is driven to rotate the ball screw 12, the ball nut 12a moves up and down in the vertical direction, and the movement is transmitted to the tip 6 via the pantograph mechanism 1 to move the tip 6 in the horizontal direction. A pulley (not shown) is attached to the drive end 4, a wire rope is wound around the pulley, and the wire rope is wound up or rewinded by a winding device arranged at an upper part of the casing, and the gripper in the storage cylinder 8 is driven up and down. In this way, the storage cylinder 8 for storing the gripper is moved in the horizontal direction, and the gripper is moved up and down to exchange the target fuel from the core 13.

[0004]

If the operation of the built-in drive unit becomes impossible due to a power failure or a failure of the ball screw with the gripper offset in the furnace, the pantograph mechanism is forcibly folded from outside the furnace. After folding, it is an essential requirement from the user to pull out the refueling machine from the container nozzle. However, there is no reliable measure to recover the refueling machine in the event of a failure.

The present invention provides a pantograph mechanism forced folding device for forcibly folding the pantograph mechanism with an external force and recovering the fuel exchanger when the pantograph mechanism cannot be operated by the built-in drive device. Aim.

[0006]

A pantograph mechanism comprising a gripper body, a plurality of arms, one end of which vertically moves up and down to extend and contract the other end in the horizontal direction, and a ball nut engaged with a ball screw. In a refueling machine including a support link for raising and lowering a driving end of an arm of a pantograph mechanism and an operation member for raising and lowering the gripper, the refueling machine is always fixed to the driving end of the arm and is engaged with the ball nut, and is fixed in advance. When applying the applied operating load from the outside, a release mechanism for releasing the engagement between the ball nut and the drive end of the arm is provided, and the drive end of the arm is forcibly pulled up via the operation member. The object is achieved by releasing the engagement between the release mechanism and the ball nut to fold the pantograph mechanism. To.

A release mechanism is attached to the drive end of the arm and always supports the lower portion of the ball nut. When a predetermined operating load is applied from the outside, the drive end and the ball are plastically deformed. The use of a nut retainer that disengages from the nut is suitable for folding the pantograph mechanism in the event of a failure.

Further, if a wire rope for lifting and lowering the gripper is used as an operation member of the gripper, it is preferable to fold the pantograph mechanism when a failure occurs.

[0009]

In the present invention, the engagement of the release mechanism for engaging the ball nut with the drive end of the arm is released by pulling up the drive end of the arm from outside with a predetermined load. When the internal drive unit of the refueling machine cannot be used, when the lifting member for raising and lowering the gripper is pulled up from the outside, the engagement between the ball nut and the drive end of the arm is released, and the pantograph mechanism can be folded.

A release mechanism is attached to the drive end of the arm and normally supports the lower portion of the ball nut. When a predetermined operating load is applied from the outside, the drive end and the ball are plastically deformed. When the drive end of the arm is forcibly pulled up using a nut retainer that disengages from the nut, the nut retainer is plastically deformed and the drive end of the arm disengages from the ball nut and the pantograph mechanism is folded. And the refueling machine can be recovered outside the furnace.

If a wire rope for gripper operation is used as the gripper operating member, the drive end of the arm is forcibly pulled up by manually winding up the wire rope connected to the pantograph mechanism and the gripper in the event of a power outage, and The presser is plastically deformed and the drive end of the arm is disengaged from the ball nut, so that the pantograph mechanism can be folded and the refueling machine can be collected outside the furnace.

[0012]

1 is a longitudinal sectional view of a refueling machine provided with a forced folding device for a pantograph mechanism according to an embodiment of the present invention. 1, the same parts as those in FIG. 6 are denoted by the same reference numerals. A pantograph mechanism 1 including a plurality of arms 1a, 1b, 1c, a ball screw 12 and a ball nut 12a supporting the pantograph mechanism 1, a casing 2 supporting the ball screw 12, and a built-in drive mechanism 5 located at an upper end of the ball screw 12. It has. The description of the distal end 6, the gripper 7, the storage tube 8, the wire rope 9 for lifting and lowering the gripper, and the winding device 10 will be omitted. 14 is a linear bearing. The fixed end 3 of the pantograph mechanism 1 is fixed to the casing 2 of the fuel exchanger suspended in the nuclear reactor, the built-in drive device 5 is driven to rotate the ball screw 12, and the pantograph mechanism 1 connected to the ball nut 12a is rotated. Is moved up and down to displace the tip 6 of the pantograph mechanism 1 in the horizontal direction. The storage tube 8 connected to the tip 6 is provided with a gripper 7, and the storage tube 8 is offset and positioned on the upper surface of the core.

After the wire rope 9 as an operation member of the gripper is routed to the connection point of the pantograph mechanism 1, the wire rope 9 is drawn out of the furnace from a nozzle (not shown) through the casing 2 and the end of the wire rope 9 is wound. It is wound by the device 10. When the wire rope 9 is wound up from the state shown in FIG. 1, a tensile force F is applied upward to the tip 6 of the pantograph mechanism 1 via the gripper 7 and the storage tube 8, and the pantograph mechanism 1 is forcibly forced by the tensile force F. , A moment M of folding occurs. At this time, a pulling force R is also generated upward at the drive end 4 by the component force of the tensile force F.

FIG. 2 is an enlarged view of the portion II in FIG. There is a ball screw 12 supported in the casing 2 and a ball nut 12a that engages with the ball screw 12, and supports the ball nut 12a via a nut retainer 11 as a release mechanism attached to the drive end 4 of the pantograph mechanism 1. . The nut retainer 11 does not undergo plastic deformation under the load applied during normal operation, and moves the drive end 4 up and down via the ball nut 12 a with the rotation of the ball screw 12 and is covered by the winding force of the wire rope 9. The pantograph mechanism 1 is configured so as to undergo plastic deformation with an operating load within a range not exceeding its own weight.

FIG. 3 is a diagram showing a state where an operation weight is applied to the driving end of FIG. FIG. 3 shows a state in which an operating load is applied as indicated by an arrow in a direction in which the drive end 4 is pulled up, and the nut retainer 11 is plastically deformed. When an operating load is further applied, the driving end 4 is disengaged from the ball nut 12a, and the driving end 4 is pulled upward, and the pantograph mechanism 1
Can be folded.

FIG. 4 is a view showing a state where the pantograph mechanism of FIG. 1 is folded. When a pulling operation load is applied to the driving end 4 of FIG.
Is completely plastically deformed, and the drive end 4 is the ball nut 1
The connection with 2a is released, and the pantograph mechanism 1 can be folded as shown in FIG. With the pantograph mechanism 1 folded in this way, the refueling machine is pulled out of the furnace together with the gripper.

FIG. 5 is an enlarged view of a portion V in FIG. In FIG. 5, the ball nut 12a remains at the original position, the nut retainer 11 is plastically deformed, the ball nut 12a passes through the outer diameter side of the ball nut 12a, and the drive end 4 moves upward. Thus, the pantograph mechanism 1 is folded. The folding device of the pantograph mechanism according to the present invention can be applied to other plants besides the high temperature gas furnace.

[0018]

According to the present invention, there is provided a release mechanism for engaging the ball nut with the drive end of the arm, and a wire for raising and lowering the gripper when the internal drive mechanism of the fuel exchanger cannot be used due to a power failure or a failure of the ball screw. By pulling up the rope from the outside, the release mechanism causes plastic deformation and releases the engagement between the ball nut and the drive end of the arm, and the pantograph mechanism can be folded away from the ball nut, and the pantograph mechanism can be folded. In the folded state,
Further, the fuel exchanger can be withdrawn from the core and collected.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a refueling machine provided with a forced folding device for a pantograph mechanism according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part II in FIG.

FIG. 3 is a diagram illustrating a state in which an operating load is applied to a driving end of FIG. 2;

FIG. 4 is a view showing a state where the pantograph mechanism of FIG. 1 is folded.

FIG. 5 is an enlarged view of a portion V in FIG. 4;

FIG. 6 is a configuration diagram of a pantograph mechanism of a conventional fuel exchanger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pantograph mechanism 1a Arm 1b Arm 1c Arm 3 Fixed end 4 Driving end 5 Built-in drive 6 Tip 9 Wire rope as operating member of gripper 11 Nut presser as release mechanism 12 Ball screw 12a Ball nut

Claims (3)

(57) [Claims] 1. A pantograph mechanism comprising a gripper body, a plurality of arms, one end of which vertically moves up and down to extend and contract the other end in a horizontal direction, and an arm of the pantograph mechanism via a ball nut engaged with a ball screw. In a refueling machine having a support link for raising and lowering the drive end of the armature and an operating member for lifting and lowering the gripper, the operating load is always fixed to the drive end of the arm and is engaged with the ball nut, and a predetermined operating load is set. When adding from outside,
A release mechanism for releasing the engagement between the ball nut and the drive end of the arm is provided, and the drive end of the arm is forcibly pulled up via the operating member, whereby the engagement between the release mechanism and the ball nut is increased. A forced folding device for a pantograph mechanism of a refueling machine, wherein the combination is released to fold the pantograph mechanism. 2. A forced folding device for a pantograph mechanism of a refueling machine according to claim 1, wherein the release mechanism is attached to a drive end of the arm, always supports a lower portion of the ball nut, and applies a predetermined operating load. A forced-folding device for a pantograph mechanism of a refueling machine, characterized in that it is a nut retainer that is plastically deformed to disengage the drive end and the ball nut when externally applied. 3. A forced folding device for a pantograph mechanism of a refueling machine according to claim 1, wherein the operation member of the gripper is a wire rope for lifting and lowering the gripper. .