JPH0381696A - Centering guide structure for fuel exchanger of pressure tube type nuclear reactor - Google Patents

Abstract

PURPOSE:To securely guide fuel and a shield seal plug for centering and to improve the reliability of fuel exchange by opening and closing a centering plate mechanically through the elevating operation of a movable guide tube. CONSTITUTION:When the movable guide pipe 7 is elevated, a centering opening/ closing cam 14 is moved up and a guide pin 13 fitted to the centering plate 9 comes into engagement to fit the pin 13 in a guide cam groove 14a. When the pipe 7 is further elevated, the pin 13 is guided along the groove 14a and the plate 9 is extruded toward the inner periphery of a magazine tube 1 against the tensile force of a spring 11 to reach a closing position. When the pipe 7 is furthermore elevated, the pin 13 is guided forcibly along the groove 14a to move in a long groove 12 is shown by an arrow (a) and the plate 9 is pressed back forcibly toward the outer periphery of the tube 1, so that the guide mechanism 4 is set an opening position.

Description

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

The present invention relates to a structure for centering and guiding fuel and shielding seal plugs in a magazine tube of a fuel exchanger for loading and unloading core components such as fuel and shielding seal plugs in a pressure tube nuclear reactor.

[Conventional technology]

As a fuel exchanger for a pressure tube reactor, a rotating drum magazine assembly consisting of a plurality of magazine tubes with magazine stopper mechanisms is housed in the pressure vessel of the fuel exchanger running below the reactor core. Among the fuel guide pipes that are piped above and below the assembly, the structure is configured such that fuel, etc. is transferred between the reactor pressure pipe and the magazine tube by a grab operation inside the aircraft through the upper guide pipe. A refueling machine is known (Japanese Unexamined Patent Application Publication No.
Furthermore, such a fuel exchanger is provided with a sliding horizontal shutter plate as a magazine stopper mechanism, and this shutter plate is opened and closed via a cam mechanism equipped on a movable guide tube on the lower guide tube side. However, it is known that a centering guide mechanism is installed in the middle of the magazine tube, using the tip of the movable guide tube as an actuator to center the stored fuel within the magazine tube. (Unexamined Japanese Patent Publication No. 61-289
838) FIGS. 4, 5 and 6 show a centering guide mechanism of a conventional fuel exchanger, and are explanatory diagrams of different operating states of the centering guide mechanism. In FIGS. 4 to 6, the magazine stopper mechanism 3
supports the weight of the fuel 2 etc. stored in the magazine tube 1 and holds it in the magazine tube 1, and also communicates with the lower guide pipe when carrying out or carrying in the fuel 2 through the lower guide pipe by operating the gripper. The stopper mechanisms 3 of the mating magazine tubes 1 are operated to open and serve to allow the passage of the fuel 2. Here, to explain the procedure of the fuel exchanger with the above configuration, first, the snout is connected to the pressure pipe of the reactor, and by lifting and lowering the grab and rotating the magazine assembly, the spent fuel etc. is extracted from the pressure pipe side. The core components are drawn into the magazine tube 1 and the pressure tubes are loaded with new fuel, which has been previously accommodated in another magazine tube 1 instead. In this state, the magazine stopper mechanism 3 is closed, and in this state, only the glove freely passes through the remaining passage inside the stopper mechanism and is operated up and down. When the fuel exchange work between the reactor and the reactor is completed in this way, the fuel exchange machine then moves to the transfer position, where it connects the lower guide pipe port to the transfer port on the fuel transfer equipment side. In this state, a gripper of a fuel handling device (not shown) is suspended through the upper guide pipe to grasp the spent fuel stored in the magazine tube. Subsequently, the magazine stopper mechanism 3 provided on the magazine tube is opened, and the spent fuel is lifted down and carried out through the lower guide pipe to the transport facility by operating the gripper. Conversely, when carrying in fuel, the new fuel is drawn into the magazine tube by following the procedure reverse to the above. As mentioned in the above procedure, the magazine stopper mechanism is opened only when carrying out or carrying in fuel through the lower guide tube, and is closed when other fuel is stored in the magazine tube. It is held inside the magazine tube. Next, the magazine stopper mechanism and centering guide mechanism in the fuel exchanger having the above configuration will be explained. Fourth
In the figure, a centering guide mechanism 4 indicated by reference numeral 4 is constructed above the magazine stopper mechanism 3 in the magazine tube l. This centering guide mechanism 4 is arranged at least three times along the circumference of the magazine tube 1 at a position that does not interfere with the magazine stopper mechanism 3.
The ball groove 5 is opened at more than a certain point, and the centering ball 6 is pushed into the ball groove 5 toward the inner circumferential side of the magazine tube 1. That is, the centering ball 6 is fitted and set in the ball groove 5 so that it can freely move in and out in the direction of arrow C toward the inner and outer peripheries. However, the inner and outer opening ends of the ball groove 5 are designed to prevent the centering ball 6 from falling out of the ball groove 5. On the other hand, on the movable guide tube 7 side facing the centering ball 6, a vertical ball escape groove 7b for releasing the restraint of the centering ball 6 is formed in a region below the actuator section 7a at the tip. FIG. 7 is a configuration diagram of a conventional magazine stopper mechanism. As shown in FIG. 7, the guide cam groove 16a of the cam mechanism 16
is divided into three regions indicated by symbols X, Y, and Z along the vertical direction, and among these regions, the X jI region is for stopping the shutter plate 17 of the magazine stopper mechanism 3 in the closed position, and the Z region is for opening the shutter plate 17. Move to the position and perform the X and Z fil
It is formed to connect between areas. Next, the second operational function of the above configuration will be described. First, FIG. 4 shows a standby state in which the magazine stopper mechanism 3 and the movable guide tube 7 are separated. In this state, the shutter plate 17 of the magazine stopper mechanism 3 is closed, and the centering ball of the centering guide mechanism 4 is closed. 6 is in a state where it can move freely within the ball groove 5 without restriction. On the other hand, FIG. 5 shows a state in which the fuel 2 is centered and guided within the magazine tube 1. That is, in this state, the movable guide tube 7 is lifted and fitted into the outer circumferential side of the magazine tube 1, and its tip 7a pushes the centering ball 6 from the outer circumferential side to release the small diameter fuel stored in the magazine tube 1. 2 to the center position within the tube. At this stage, the shutter plate 17 of the magazine stopper mechanism 3 is guided by the X'RJ area of the guide cam groove shown in FIG.
is in a closed state. Next, FIG. 6 shows that the movable guide tube 7 is further raised from the state shown in FIG.
This figure shows a state in which it is guided by the Zfiff area of a. In this state, the ball relief groove 7b on the movable guide tube 7 side faces the centering ball 6 of the centering guide mechanism 4, and the restraint of the centering ball 6 is released. The centering ball 6 can therefore move freely within the ball groove 5. Next, the procedure for carrying in fuel between the fuel exchanger and the external fuel transfer equipment will be explained based on the operating states shown in FIGS. 4 to 6. (1) When carrying in fuel When carrying in the fuel 2 by drawing it into the empty magazine tube 1 through the lower guide pipe (not shown), the first step is to raise the movable guide pipe 7 until it reaches the state shown in Fig. 6. The shutter plate 17 of the magazine stopper mechanism 3 is opened by operation, and a fuel passage leading into the magazine tube 1 is secured. In the next step, a fuel handling machine lifts and draws fuel into the magazine tube 1 through the lower guide pipe. Here, when the fuel 2 is pulled up above the position of the centering ball 6 at one end, the movable guide tube 7 is slightly lowered and the fifth
Set the state of the diagram. In this state, the shirt plate 17
closes. Next, when the fuel is lowered into the magazine tube 1 by the fuel handling machine, in this process the fuel 2 is centered and guided by the centering ball 6 that protrudes from the rear side where the magazine tube 1 is not located, and then passes through the magazine stopper mechanism. It lands on the shirt top board 17 of No.3. Therefore, the fuel 2 properly engages with the retaining protrusion of the shirt flap plate 17 and is mechanically interlocked. When this process is completed, the movable guide tube 7 is finally
is lowered to the standby position shown in FIG. 4, and the series of fuel storage operations is completed. (2) When transporting the shielding seal plug The shielding seal plug has a larger diameter than the fuel, and its outer diameter is approximately equal to the inner diameter of the magazine tube 1, so in this case, the centering guide function described above is unnecessary. . Therefore, the procedure for drawing the shielding seal plug into the empty magazine tube is as follows. First, the movable guide tube 7 is raised from the standby position shown in FIG. 4 to the state shown in FIG. 6 to open the magazine stopper mechanism 4, which is the same procedure as in the case of fuel. Next, in this state, the shielding seal plug is drawn into the magazine tube 1 by lifting the fuel handling machine. At this time, even if the centering ball 6 protrudes toward the inner circumferential side of the magazine tube 1, the centering ball 6 is not restrained, so that the shielding seal plug can freely rise inside the magazine tube 1. Here, lift the shielding seal plug so that the lower end is further above the position of the centering ball 6, then lower the movable guide tube 7 to return to the state shown in FIG. Close 17. During this return process, the centering ball 6 temporarily protrudes toward the inner periphery of the magazine tube as it passes through the state shown in Figure 5. However, in the next process, when the shielding seal plug is suspended in the magazine tube, Since it is pushed by the seal and retracts toward the outer circumference, it does not pose any problem. Finally, the shielding seal plug is landed on the shutter plate 17 of the magazine stopper mechanism, and the work of carrying it into the magazine tube is completed. The inner diameter of the magazine tube 1 is set to match the fuel and shielding seal plugs, which are core components housed here, and the shielding seal plug has a large inner diameter, and is about 20 mm larger than the diameter of the fuel 2. It is. For this reason,
When storing the fuel 2 in the magazine tube l, the fuel 2 is placed in the magazine tube 1 so that the lower part of the fuel is reliably loaded in the center of the magazine stopper mechanism 3 even if the fuel 2 is stored eccentrically due to the gap with the magazine tube l. Centering guide mechanism 4 that guides centering to the center position of
The conventional centering guide mechanism 4 includes centering balls 6 that are fitted into ball grooves 5 that are distributed and opened on the circumferential surface of the magazine tube l so as to be freely retractable.
The distal end 7a of the movable guide tube 7 facing the magazine tube 1 is used as an actuator to push in from the outer circumferential side of the magazine tube 1 and project it to the inner circumferential side, thereby centering and guiding the stored fuel.

[Problem to be solved by the invention]

In the conventional structure, when storing a large-diameter shielding seal plug, the centering ball is allowed to move freely within the ball groove, and the centering ball is pushed back toward the outer periphery of the magazine tube by the outer circumferential thickness and lower end surface of the shielding seal plug. The purpose is to form a passageway, and there is no mechanism for forcibly moving it in the opening direction. Therefore, when the centering ball protrudes toward the inner circumference of the magazine tube, the centering ball becomes stuck due to impurities adhering to the ball, and even if the outer circumferential surface or lower end surface of the shielding seal plug hits the centering ball, the ball will not move. First, there was a problem that the shielding seal plug could not be accommodated. SUMMARY OF THE INVENTION An object of the present invention is to provide a centering guide mechanism for a fuel exchanger for a pressure tube nuclear reactor, in which the centering guide mechanism is mechanically opened and closed to center and guide fuel and a shielding seal plug within a magazine tube. .

[Means to solve the problem]

The above object includes two housings disposed opposite to each other at the lower end of a magazine tube, a centering guide mechanism having a movable centering plate attached to each housing, and four centering plates engaged with the centering guide mechanism. It consists of a movable guide tube with an opening/closing cam attached to the upper part and forming a guide section for objects to be handled.The movable guide tube is raised and lowered and the centering centering plate is opened and closed by the centering opening/closing cam to move the fuel or shielding seal plug into the magazine. This is achieved by a centering guide structure of a pressure tube reactor refueling machine that is centered within the tube.

[For use]

The centering guide mechanism attached to the lower end of the magazine tube is engaged with the centering opening/closing cam attached to the upper part of the movable guide tube, and the centering plate of the centering guide mechanism is mechanically opened and closed, and the fuel and shielding seal plugs are connected to the magazine tube. It can be used as a centering guide.

【Example】

The present invention will be described in detail below based on the drawings. FIG. 1 is a block diagram showing the centering guide structure of a fuel exchanger for a pressure tube nuclear reactor according to an embodiment of the present invention, and FIG.
3 is a sectional view taken along the line A--A in FIG. 1. 1 to 3, the centering guide structure according to the embodiment of the present invention includes two housings 8 disposed opposite to each other at the lower end of the magazine tube 1, and a centering shaft 10 attached to each of the housings 8.
a centering plate 9 supported by the centering shaft and movable in the radial direction; a centering guide pin 13 attached to the centering plate 9; and a centering ring whose ends are fixed to the housing 8 and the centering plate 9 and which holds the centering plate 9 in the opening direction. Spring 1
1, four centering opening/closing cams 14 having guide cam grooves 14a that engage with the centering guide pins 13, and the centering opening/closing cams 14 are attached to the upper part to form a guide section for the handled object. It consists of a movable guide tube 7. The magazine stopper mechanism 3 is attached below the centering guide mechanism 4 of the housing 8 and includes a movable stopper pin 15 supported by a shaft. It engages with the groove 14b. When the movable guide tube 7 is in the lowered position, the centering plate 9 and the centering opening/closing cam 14 are separated from each other, and the centering plate 9 is not restrained by the centering opening/closing cam 14 but is moved by the tension of the centering plate spring 11. 9 is held in the open position. When the movable guide tube 7 is raised from this state, the centering opening/closing cam 14 moves upward together with the movable guide tube 7, and the centering guide pin 13 attached to the centering plate 9 is engaged, and the bottle 13 is fitted into the guide cam groove 14a. I become absorbed in it. Subsequently, when the movable guide tube 7 further rises, the centering guide pin 13 is mechanically guided along the guide cam groove 14a, and the centering plate 9 moves against the tension of the centering plate spring 11 to the inner peripheral side of the magazine tube 1. The centering plate 9 is pushed out to the closed position. At this time, the centering guide pin 13 is at the X position. When the movable guide tube 7 is further raised from this state, the centering guide pin 13 moves into the guide cam groove 14 of the cam mechanism.
The centering plate 9 is forcibly guided along the direction a and moves in the long groove 12 in the direction a, and the centering plate 9 is forcibly pushed back toward the outer circumferential side of the magazine tube 1 and the centering guide mechanism 4
is in the open position. At this time, when the movable guide tube 7 of the magazine stopper mechanism 3 is raised, the stopper pin 15 engages with the guide cam groove 14b drilled below the centering opening/closing cam 14, the magazine stopper mechanism 3 also becomes the open position, and the shielding seal plug Elevating and descending passages will be secured. At this time, the centering guide pin 13 is in the Y position of the guide cam groove 14a.

【Effect of the invention】

This invention consists of a housing disposed at the lower end of a magazine tube, a centering guide mechanism attached to the housing, a centering opening/closing cam that engages with the centering guide mechanism, and a movable guide tube to which the centering opening/closing cam is attached. The centering plate of the centering guide mechanism opens due to the vertical movement of the movable guide tube. Since the closing operation is performed mechanically, the centering guide of the fuel and shielding seal plug can be performed reliably. Furthermore, since the centering guide mechanism is operated with a large driving force, it is possible to cover malfunctions and improve the reliability of the fuel exchanger.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the centering guide structure of a fuel exchanger according to an embodiment of the present invention, Fig. 2 is a side sectional view of Fig. 1, Fig. 3 is a sectional view taken along line AA of Fig. 1, and Fig. 4 7 to 7 show the centering guide mechanism of a conventional fuel exchanger, FIGS. 4 to 6 are explanatory diagrams of different operating states of the centering guide mechanism, and FIG. 7 shows the configuration of a conventional magazine stopper mechanism. It is a diagram. l: Magazine tube, 2: Fuel, 3: Magazine stopper mechanism, 4: Centering guide mechanism, 7: Movable guide tube, 8: Housing, 9: Centering plate, 10:
Centering shaft, 11: Centering plate spring, 1
2: Long groove, 13: Centering guide pin, 14: Centering opening/closing cam, 14a, 14b guide cam groove, 1
5: Stopper pin. Flute 4 Sendai

Claims (1)

[Claims] 1) It has a rotating drum type magazine assembly consisting of a plurality of fuel storage magazine tubes equipped with a magazine stopper mechanism at the lower end, and atoms are transported through fuel guide pipes installed above and below the magazine assembly. In a fuel exchange machine that exchanges fuel with a furnace and transfers fuel with an external fuel transfer facility, two housings are arranged opposite to each other at the lower end of the magazine tube, and two housings are attached to the respective housings. It consists of a centering guide mechanism that has a movable centering plate, and a movable guide tube that has four centering opening/closing cams attached to the upper part that engage with the centering guide mechanism and forms a guide for objects to be handled. A centering guide structure for a fuel exchanger for a pressure tube nuclear reactor, characterized in that the centering plate is opened and closed by the centering opening/closing cam to center the fuel or the shielding seal plug within the magazine tube.