JP3104471B2 - Refueling machine gripper for fast breeder reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gripper having a direction determining function for a fuel exchanger of a fast breeder reactor.

[0002]

2. Description of the Related Art In a fast breeder reactor, the speed at which neutrons are absorbed by a nuclear source material to produce new fissile material is higher than the speed at which nuclear fuel required for a chain reaction is consumed using fast neutrons. Since it is a furnace and takes out heat from a small core, it uses sodium, which has a good heat transport capacity, as a coolant. Since sodium must not be exposed to air, it is sealed in the reactor vessel and the liquid level is covered with an inert gas. The furnace top lid is strictly sealed and serves as a shield. However, the fuel needs to be changed without opening the lid, so various measures are required.

FIG. 3 is a sectional view of a fuel exchanger of a fast breeder reactor, (A) is a longitudinal sectional view, and (B) is a BB sectional view of (A). A large-rotation plug 10 and a small-rotation plug 11 eccentrically mounted on the large-rotation plug 10 are arranged above the core.
2 is provided. At the time of refueling, a telescopic arm type fuel exchanger is mounted on the small rotary plug 11, the refueling machine is moved near the fuel to be exchanged, and fuel is inserted from the upper part of the core to exchange. The telescopic arm type fuel exchanger 12 raises and lowers an inner shell built in the main body by rotating a ball screw shaft for raising and lowering, and raises and lowers a stem (not shown) connected to the inner shell. By raising and lowering this stem,
The entire arm can be extended and contracted horizontally while the gripper body 1 is kept vertical. The fuel of the fast breeder reactor has a substantially hexagonal prism shape, and the fuel is inserted so that the sides of the fuel are aligned with the sides of the surrounding fuel. For this purpose, the surface of the fuel itself has an orientation determining function based on unevenness along the longitudinal direction, and this function allows the fuel to be inserted smoothly. As described above, the conventional refueling machine has only a grasping / releasing function for grasping the fuel and a gripper lifting / lowering function for inserting / pulling out the fuel, and has no function of determining the direction of the fuel.

However, the function of determining the orientation of the fuel itself may be difficult to insert depending on the combination of the angle of the fuel to be inserted and the angle of the surrounding fuel. Therefore, when the function of determining the orientation of the fuel itself does not work, the rotation of the large rotary plug 10 having the rotation center at the core center as shown in FIG. 3 and the rotation of the small rotary plug 11 having the rotation center at a position eccentric from the core center as shown in FIG. By combining the rotation, the rotation of the refueling machine 12 mounted on the small rotary plug 11, and the expansion and contraction of the arm, the orientation is determined when the fuel is inserted.

[0005]

In a conventional refueling machine, when the orientation determining function of the fuel itself does not work,
Since the large-rotation plug, small-rotation plug, and refueling machine must be individually rotated, it takes time to calculate and rotate the angle, and as a result, it takes a long time to exchange fuel. In the future, rotating plugs will be eliminated and the upper core mechanism will be lifted or removed from the core during refueling to secure a space for refueling, and a single refueling machine will replace the entire area of the reactor. Is expected to do.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a refueling machine gripper which has an orientation determining function in a fast breeder reactor itself, has a reduced refueling time, and is applicable even when a rotary plug is not used. .

[0007]

SUMMARY OF THE INVENTION A fast breeder reactor having a support member connected to a ball screw shaft, a gripper body supported by the support member, and an actuator that penetrates the gripper body and opens and closes a gripper claw. In the refueling machine gripper, the gripper body is constituted by an upper portion of the gripper body supported by the support member and a lower portion of the gripper body rotatably supported by the upper portion of the gripper body and provided with the gripper claws. And a holder fixed in the lower portion of the gripper main body, and formed with a spiral groove for guiding the pin on the inner surface thereof, and a holder for penetrating the actuator. When moving in the closing direction, the gripper opens as the holder rotates. By rotating said gripper while, to achieve the above object.

When the actuator is moved from the gripper open position to the gripper claw closing direction, if the gripper claw is rotated by a predetermined angle while the gripper claw is open, the orientation of the fuel can be determined. It is suitable.

[0009]

In the present invention, the gripper body is lowered to a predetermined position while gripping the fuel with the gripper claws,
The actuator is moved in the direction in which the gripper claws close. At this time, in the operation of the actuator, the pawl remains open in a predetermined range. The pin attached to the actuator moves along the spiral groove of the holder attached to the gripper body, and when the holder rotates, the lower part of the gripper body supporting the holder rotates with the gripper open, and is gripped by the gripper. The direction of the fuel is determined by rotating the fuel. Since the gripper claw rotates by a predetermined angle, if new fuel is oriented and inserted between adjacent fuels and does not move, the gripper claw rotates by rubbing the surface where fuel is engaged and the fuel does not rotate .

[0010]

FIG. 1 is a configuration diagram of a refueling machine gripper according to an embodiment of the present invention. The gripper main body 1 includes a gripper main body upper portion 1a supported by a support member coupled to a screw shaft (not shown), and a gripper main body lower portion 1b rotatably supported by the gripper main body upper portion 1a and having a gripper claw 2. . The actuator 3 penetrating the gripper body 1 is moved vertically by a gripper opening / closing mechanism (not shown) to close or open the gripper claw 2. Further, a pin 4 attached to the actuator 3 and extending in the horizontal direction, and a spiral groove 5a fixed in the lower portion 1b of the gripper body and guiding the pin 4 are formed on the inner surface, and a holder 5 for penetrating the actuator 3 is provided. .

FIG. 2 is a block diagram showing the principle of operation of the refueling machine gripper shown in FIG. In FIG. 2, the ball screw shaft 7
Is rotated to raise and lower the support member 6 connected to the shaft. By raising and lowering the support member 6, the gripper body 1 supported by the support member 6 is raised and lowered. The support member 6 includes a spline shaft 8 and a ball screw nut 9 connected to the spline shaft 8 via a gear. The actuator 3 has a ball screw carved on the upper part and is connected to a ball screw nut 9. By externally rotating the spline shaft 8, the ball screw nut 9 rotates and the actuator 3 moves up and down, and the gripper claw 2 is opened and closed by the tip of the actuator 3. When inserting new fuel into place, work in the following sequence. (1) The gripper body 1 holding the fuel is lowered to a predetermined position in the furnace, and the actuator 3 is moved in the closing direction of the gripper claw 2. At this time, the movement range of the actuator 3 in the state where the gripper claw is open is the range of δ in FIG. (2) The pin 4 of the actuator is a spiral groove 5 of the holder 5
a, the holder 4 engaging with the pin 4 rotates along the spiral groove 5a, and the lower gripper body 1b supporting the holder 5 rotates. I do. The rotation angle of the holder is determined by the shape of the spiral groove 5a, and rotates up to, for example, 30 °. (3) As a result, the gripper claw 2 supported by the gripper main body lower part 1b rotates, and the fuel rotates together with the gripper claw 2 to determine the direction of the fuel. (4) Further, the actuator 3 is moved, the gripper claw 2 is closed, the fuel is separated from the gripper claw 2, and the fuel is inserted into the furnace.

[0012]

According to the present invention, when the azimuth determining function of the fuel itself does not work effectively at the time of refueling of the fast breeder reactor, the refueling machine gripper gripping the fuel is rotated,
Fuel can be inserted smoothly into the furnace. According to the present invention, the direction of the fuel can be determined by the rotation of the gripper itself without rotating the rotary plug, so that the fuel exchange time is reduced. The fuel exchanger gripper according to the present invention can be applied even when a rotary plug is not used.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refueling machine gripper according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an operation principle of the refueling machine gripper of FIG. 1;

FIGS. 3A and 3B are cross-sectional views of the fuel exchanger of the fast breeder reactor, where FIG. 3A is a vertical cross-sectional view and FIG. 3B is a cross-sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gripper main body 1a Upper gripper main body 1b Lower gripper main body 2 Gripper claw 3 Actuator 4 Pin 5 Holder 5a Spiral groove 12 Refueling machine

Claims (2)

(57) [Claims] 1. A fuel exchange gripper for a fast breeder reactor, comprising: a support member connected to a ball screw shaft; a gripper body supported by the support member; and an actuator that penetrates the gripper body and opens and closes a gripper claw. The gripper body is constituted by an upper portion of the gripper body supported by the support member and a lower portion of the gripper body rotatably supported by the upper portion of the gripper body and having the gripper claws, and is attached to the actuator and extends horizontally. A pin and a holder fixed in the lower portion of the gripper main body, a spiral groove for guiding the pin is formed on the inner surface, and a holder for penetrating the actuator is provided, and the actuator is moved from the gripper claw open position to the gripper claw close direction. When moving, the gripper remains open with the rotation of the holder. Refueling machine gripper fast breeder reactor, characterized in that rotating the path pawl. 2. The gripper claw of a fast breeder reactor according to claim 1, wherein when the actuator is moved from the gripper open position to the gripper claw close direction, the gripper claw is opened at a predetermined angle. A refueling machine gripper for a fast breeder reactor, characterized by rotating