JPH02129596A - Fuel exchanger for fast breeder - Google Patents

Abstract

PURPOSE:To set fuel at a specific position by providing a fuel orientation device which drives and rotates a gripper gripping the fuel from outside a nuclear reactor and a fuel discriminating device which discriminates the discrimination pattern of a fuel top part. CONSTITUTION:An orientation rod 8 is connected to the gripper 4 from above a main body barrel 1 while a pantagraph arm 3 is folded. The fuel is positioned at the specific position by rotating the gripper 4 by a fuel rotary driving mechanism 6. The fuel discriminating device 9 is fitted horizontally to the lower end of the main body barrel 1 opposite the discrimination pattern of the fuel 5, and an ultrasonic wave transmitter and a receiver are provided. The gripper 4 engages the fuel 5 and can move up and down, and an ultrasonic wave is sent to above the fuel 5 from the device 9 toward an annular discrimination pattern. Its reflected wave is received to discriminate the kind of the fuel 5. The gripper 4 grips the fuel 5 in a hold-down tube 2 and a rod 8 is lowered to position the fuel 5 in a specific direction by a fuel rotating mechanism 6.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel exchanger for exchanging fuel in a fast breeder reactor that uses liquid metal as a coolant.

[Conventional technology]

FIG. 4 is a sectional view of a conventional refueling machine for a fast breeder reactor. In FIG. 4, the pantograph arm 3, which is installed across the hold-down tube 2 and the boss 12 screwed into the ball screw of the arm telescoping drive mechanism on the main body trunk l side, is located at the central portion in the longitudinal direction. The arm plate has a step formed thereon, and flanges are formed at both ends of the arm plate, which project toward opposite sides. A gripper 4 grips fuel 5 and stores it in a hold down tube 2. 6 is a fuel rotation drive mechanism. 7 is a gripper lifting/lowering drive device. With this configuration, when the pantograph arm 3 is folded from the fuel exchange position where the pantograph arm 3 is extended horizontally and the hold-down tube 2 is pulled out to the side of the main body 1, the arm extension/contraction drive mechanism on the main body 1 side One pantograph arm 3 is fitted into the U-shaped groove of the flange. The fuel of a fast breeder reactor has an elongated structure with a hexagonal cross section, and the reactor core is configured such that the fuel is guided to each other in a honeycomb shape. When inserting fuel into the reactor core using a refueling machine, all fuels are provided with crown-shaped diagonal protrusions on the top and bottom of the fuel so that the orientation of the fuel matches, and as the fuel is pushed into the core, the fuel is positioned in a predetermined orientation. (This is called fuel self-orientation). In addition, each core component (fuel assembly, control rod assembly, etc.)
By making the shapes of the lower entrance nozzle part and the connecting part of the lower part of the core into which this entrance nozzle is inserted different for each type of core component, if the wrong core component is installed in the core, It becomes impossible to complete the insertion, and it is possible to judge from the inserted state whether or not the type of core component is correct.

[Problem to be solved by the invention]

The conventional method of confirming core components using self-orientation of the fuel itself or the joint structure at the bottom of the core is as follows:
This method has been implemented for relatively small-power nuclear reactors, and when applied to large-scale nuclear reactors, the following problems arise. (1) In large reactors, the core becomes larger and the demand for extending the fuel life increases, so the deformation (lateral and height variations, etc.) of the hexagonal hole in the core side into which the fuel is inserted becomes relatively large. In such cases, even if we hope to set the direction of the fuel by fuel self-orientation, it is often unsuccessful, resulting in an increase in the refueling period or a decrease in plant utilization. (2) In large reactors, a large number of core components are replaced during one refueling period, and for safety reasons, there is a growing demand for detection of mishandling of core components. An object of the present invention is to provide a fuel exchange machine equipped with a fuel orientation device that rotationally drives a gripper that grips fuel from outside the reactor, and a fuel identification device that identifies an identification pattern engraved on the top of the fuel. shall be.

[Means to solve the problem]

The above object is to provide a fuel orientation device consisting of an orientation rod that is detachably attached to a gripper that grips and releases fuel, a fuel rotation drive mechanism that can rotate this orientation rod from outside the reactor, and a fuel orientation device that is engraved on the top of the fuel. A fuel exchanger for a fast breeder reactor is installed horizontally at the lower end of the main body so as to face an identification pattern consisting of a combination of annular grooves, and is equipped with a fuel identification device consisting of an ultrasonic receiving and transmitting device. achieved.

[For use]

A fuel orientation device that can rotate the gripper that grips and releases fuel from outside the reactor allows the rotation direction of the fuel to be set with the pantograph arm folded, and a fuel identification device that is installed horizontally below the main body shell. can identify the type of core component that the refueling machine is grasping.

【Example】

The present invention will be described in detail below based on the drawings. FIG. 1 is a sectional view showing the structure of a fast breeder reactor refueling machine according to an embodiment of the present invention, FIG. 2 is an outline view showing the state of fuel identification by the fuel identification device of the refueling machine of FIG. 1, and FIG. 1st
FIG. 3 is a cross-sectional view of the fuel rotation drive section of the fuel exchanger shown in the figure. 1st
Figure, Figure 2. In FIG. 3, the same parts as in FIG. 4 are given the same numbers. In FIG. 1, the pantograph arm 3 is installed across the hold-down tube 2 and the boss 12 screwed into the ball screw of the arm telescopic drive mechanism on the body trunk 1 side. Flange portions are formed on the arm plate having different steps and on both ends of the arm plate projecting to opposite sides. With this configuration, when the pantograph arm 3 is folded from the fuel exchange position where the pantograph arm 3 is extended horizontally and the hold-down tube 2 is pulled out to the side of the main body 1, the arm extension/contraction drive mechanism on the main body 1 side One pantograph arm 3 is fitted into the U-shaped groove of the flange. As shown in FIG. 1, with the pantograph arm 3 folded, an orientation rod 8 is connected to the gripper 4 from the upper part of the body trunk 1, and a fuel rotation drive mechanism 6 at the upper end of the fuel exchanger
By rotating the gripper 4, the fuel 5 can be positioned in a predetermined direction. The orientation rod 8 and the fuel rotation drive mechanism 6 are collectively referred to as a fuel orientation device 11. 1 and 2, the fuel identification device 9 is
It is attached horizontally to the lower end of the fuel 5 so as to face the identification pattern 10 of the fuel 5, and is equipped with an ultrasonic transmitting device and a receiving device. The gripper 4 is engaged with the fuel 5 and is moved up and down in the direction of the arrow A. The upper part of the fuel 5 is engraved with an identification pattern consisting of a combination of annular grooves, and the gripper 4 is engaged with the fuel 5 and is engraved with an identification pattern consisting of a combination of annular grooves. The fuel identification device 9 emits ultrasonic waves and receives reflected waves to identify the type of fuel 5. In FIG. 3, the gripper 4 grips the fuel 5 within the hold-down tube 2, lowers the orientation rod 8, engages the orientation rod 8 with the gripper 4, and directs the fuel 5 in a predetermined direction by the fuel rotation drive mechanism 6. position. The gripper 4 is raised and lowered by a gripper raising and lowering drive device 7.

【Effect of the invention】

According to this invention, since the fuel orientation device that can rotate the gripper from outside the reactor is provided, the fuel gripping the gripper can be set in a predetermined orientation. In addition, a fuel identification device consisting of an ultrasonic receiver and transmitter is attached horizontally to the lower end of the zero body motion, so the identification pattern consisting of a combination of ring-shaped grooves carved into the top of the fuel can be identified and replaced. You can check the type of fuel that should be used.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fast breeder reactor refueling machine according to an embodiment of the present invention, and FIG. 2 is a diagram showing a state in which fuel is identified by the fuel identification device of the fast breeder reactor refueling machine of FIG. 1. FIG. 3 is a sectional view of the fuel rotation mechanism in FIG. 1, and FIG. 4 is a sectional view of a conventional fast breeder reactor refueling machine. 1: Main body trunk, 2: Hold down tube, 3: Pantograph arm, 4 Nigelippa, 5: Fuel, 6: Fuel rotation drive mechanism, 7: Gripper lifting/lowering drive device, 8: Orientation rod, 9: Fuel identification device, lO: Identification pattern, 11: Fuel orientation device. Figure 1 Figure 1

Claims (1)

[Claims] 1) A pantograph type fuel exchanger installed in the reactor vessel of a fast breeder reactor to exchange fuel with the reactor core, and an orientation rod that is removably arranged on a gripper that grips and releases fuel, and this orientation rod. A fuel orientation device consisting of a fuel rotation drive mechanism that can be rotated from outside the reactor, and a fuel orientation device that is horizontally attached to the lower end of the main body so as to face an identification pattern consisting of a combination of annular grooves cut into the top of the fuel. 1. A fuel exchanger for a fast breeder reactor, characterized in that it is attached to a fuel identification device comprising an ultrasonic receiving and transmitting device.