JP2519983B2 - Gripper for refueling machine of fast breeder reactor - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a gripper of an offset arm type fuel exchanger for exchanging spent fuel and fresh fuel in a core in a liquid metal cooled fast breeder reactor.

[Prior art]

As this type of fuel exchanger, the one shown in FIG. 3 is conventionally known. The offset arm refueling machine includes a gripper 20, an offset arm 18, a holddown tube 2, a main body 19, and a drive unit 21. Rotating plug 2 at the top of the reactor
Insert the body barrel 19 into the furnace through the hole 2 and use the offset arm 1
In the hold-down tube 2 supported by 8, the rotary motion transmitted from the drive unit 21 is converted into an up-and-down motion by the ball screw 12, and the gripper 20 is engaged with the ball screw 12 and moved up and down to move the reactor core 8 To remove the fuel. When inserting the fuel 8 into the core, the fuel exchanger is operated in the reverse order to the above, and the gripper 20 follows the self-orientation of the fuel 8 to set the orientation of the fuel 8. When the fuel 8 is drawn out, the holddown tube 2 is lowered, and when the fuel is drawn out, the holddown tube is pressed so that the fuel around the target fuel does not rise at the same time. The opening and closing of the gripper claw will be described below with reference to the drawings. FIG. 4 is a sectional view of the gripper of the fuel exchanger of FIG. 3, and FIG. 4 (A) shows the case with the claw closed and FIG. 4 (B) shows the case with the claw open. In FIG. 4 (A), the main body cylinder of the gripper connected to the ball screw 12 in the holddown tube 2 descends, and the gripper claw 7 passes through the cam track 14, so that the roller 15 supporting the gripper claw 7 is released. The gripper pawl 7 is pushed to close so that the gripper pawl 7 is inserted into the fuel 8 without engaging the fuel. Further, as shown in FIG. 4 (B), the holddown tube 2 is lowered from the position of the holddown tube 2 in FIG. By raising the roller 15 relative to 2, the roller 15 moves over the cam track 14, the roller 15 is pushed by the hold down tube 2, the gripper claw 7 is opened, and the gripper claw engages with the fuel 8.

[Problems to be Solved by the Invention]

In the above-mentioned conventional gripper, since the opening and closing of the gripper claw can be performed only when the gripper is at the lowermost end, there is no danger of dropping the fuel and the structure is simple, but it has the following drawbacks. (1) Since the pawls are opened and closed according to the relative positions of the gripper ascending and descending and the hold down tube ascending and descending, the open / closed state of the pawl cannot be regarded as a one-to-one object with the movement of the pawl. (2) Since it is not possible to detect whether or not the gripper securely grips the fuel without gripping it empty after it comes into contact with the fuel,
There is a risk of half-grabbing. In order to eliminate the drawback of (1) above, a method may be considered in which the operation is transmitted from outside the furnace through a number of links to open and close the gripper claws, but in this case the structure becomes complicated and fuel drop It has the drawback of causing danger. According to the present invention, the open / close state of the gripper can be detected by an operation that corresponds to the opening / closing of the gripper claw outside the furnace in a one-to-one manner, and the gripper that does not have a risk of being caught empty by detecting the contact of the gripper with the fuel. The purpose is to provide.

[Means for Solving the Problems]

According to the present invention, the above-mentioned object is a ball nut that is combined with a ball screw in a holddown tube to move a gripper up and down, a gripper body that moves up and down following the ball nut, and a rotary drive from outside the furnace to be built in the gripper body. Spline that is gear-coupled with the ball screw for opening and closing the claw,
A pawl opening / closing rod that moves up and down by rotation of the pawl opening / closing ball screw, a lock member that is coupled to the gripper body by a spring with a gripper pawl lock mechanism and a sensing shaft, and is displaceable around a fulcrum at the tip of the gripper body. It is achieved by a gripper for a refueling machine of a fast breeder reactor, which gripper is supported by the gripper.

[Work]

According to the present invention, it is detected that the gripper claw has reached the fuel due to the sensing shaft hitting the fuel, and the spline is rotationally driven to move the claw opening / closing rod up and down to securely engage the gripper claw with the fuel. Therefore, the fuel can be completely grasped by the gripper claws.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are assembly drawings of a gripper for a fuel exchanger of a fast breeder reactor according to an embodiment of the present invention. FIG. 1 shows a state in which a gripper claw is separated from fuel, and FIG. Fig. 1 (B) is a plan view, Fig. 1 (B) is a plan view, Fig. 2 shows a state in which the gripper claws are engaged with fuel, Fig. 2 (A) is a cross section, and Fig. 2 (B) is a plan view. Is. The same parts as those in FIGS. 3 and 4 are designated by the same reference numerals. In FIG. 1 (A), the ball screw 12 is rotationally driven in the holddown tube 2 to move the ball nut 3 up and down, and the gripper 20 attached to the ball nut 3 is moved up and down. When the spline 1 attached to the holddown tube 2 is rotationally driven from outside the furnace, the ball nut 3
The ball screw 5 for opening and closing the claw rotates via the gear 4 in the main body cylinder 19 that moves up and down in accordance with. When the ball screw 5 rotates, the pawl opening / closing rod 6 screwed to the ball screw 5 is moved up and down. The lock member 16 is attached to the body barrel 19 by a spring so that the pawl opening / closing rod 6 passes through the lock member 16. When the sensing shaft 9 attached to the tip of the lock member 16 comes into contact with the head of the fuel 8, the sensing shaft 9 is pushed in and the gripper claw locking mechanism of the lock member 16 and the gripper claw 7 are engaged. The engagement is released, and the gripper claw 7 can be freely displaced. Further, the lock member 16 is lowered to move the gripper claw 7 in the opening direction so that the gripper claw 7 is engaged with the fuel 8. When the fuel 8 is held and the fuel 8 is lifted, the gripper claw 7 and the fuel 8 are engaged and the main body cylinder 19 is raised, so that the lock member 16 is relatively lowered with respect to the main body cylinder 19 and the second The gripper claw 7 is locked in the open state by the gripper claw lock mechanism 10 as shown in FIG. Therefore, the gripper claw 7 cannot be opened unless the fuel 8 is inserted and the sensing shaft 9 is pushed in again as shown in FIG. 1, so there is no risk of dropping the fuel. Further, in the conventional gripper, the fuel follows the self-orientation by sliding the gap between the fuel and the gripper claw, but in this example, the gripper rotary bearing 11 provided between the main body cylinders 19 is used. The gripper claw can be easily rotated following the fuel.

【The invention's effect】

According to this invention, when the sensing shaft hits the fuel, it is detected that the gripper claw has reached the fuel, the gripper claw locking mechanism is automatically disengaged, the gripper claw is closed, and the gripper claw is inserted into the fuel. After that, the spline is rotationally driven to lower the pawl opening / closing rod to open the gripper pawl and engage the fuel, so that the fuel can be completely grasped and the empty grasp of the fuel can be prevented.

[Brief description of drawings]

FIG. 1 is an assembly view showing a state in which a gripper claw of a gripper for a refueling machine of a fast breeder reactor according to an embodiment of the present invention is opened. FIG. 1 (A) is a vertical sectional view and FIG. 1 (B) is a plan view. FIG. 2 is an assembly view showing a state in which the claws of the gripper for a fuel exchanger of FIG. 1 are closed, FIG. 2 (A) is a longitudinal sectional view, FIG. 2 (B) is a plan view, and FIG. FIG. 4 is an assembly view of a fuel exchanger of a fast breeder reactor according to an example, FIG. 4 is a vertical cross-sectional view of gripper claws of the fuel exchanger of FIG. 3, and FIG. 4 (A) is a diagram showing a state in which the gripper claws are closed; FIG. 7B is a diagram showing a state in which the gripper claws are opened. 1: Spline, 2: Holddown tube, 3: Ball nut, 4: Gear, 5: Claw opening / closing ball screw, 6: Claw opening / closing rod, 7: Gripper claw, 8: Fuel, 9: Sensing shaft, 10: Gripper Claw lock mechanism, 12: ball screw, 20: gripper.

Claims (1)

(57) [Claims] 1. A ball nut that is combined with a ball screw in a holddown tube to move a gripper up and down, a gripper body that moves up and down following the ball nut, and a ball for opening and closing a claw that is rotationally driven from outside the furnace and built in the gripper body. A spline that is gear-coupled to a screw, a claw opening / closing rod that moves up and down by rotation of the claw opening / closing ball screw, a lock member that is coupled to the gripper body by a spring and has a gripper claw locking mechanism and a sensing shaft, and the tip of the gripper body. A gripper for a refueling machine of a fast breeder reactor, characterized in that the gripper claw is supported by a portion so as to be displaceable around a fulcrum.