JPH0337159B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a fuel exchanger for loading and unloading core components such as fuel and shielding seal plugs for pressure tube nuclear reactors.

[Prior art and its problems]

As a fuel exchanger for the pressure tube reactor mentioned above, a rotating drum type magazine assembly consisting of a plurality of magazine tubes with a magazine stopper mechanism is housed in the pressure vessel of the fuel exchanger that runs below the reactor core. , and among the fuel guide pipes that are piped above and below the magazine assembly, loading and unloading of fuel, etc. is carried out through the upper guide pipe through the pipe between the reactor pressure pipe and the magazine tube by a grab operation inside the aircraft. A fuel exchange machine is known that is configured to transfer fuel, etc. to and from an external fuel transfer facility through a lower guide pipe (Japanese Patent Application Laid-Open No. 197893), and furthermore, such a fuel exchange machine is However, the same application discloses a magazine stopper mechanism that is provided with a sliding horizontal shutter plate, and that this shutter plate is opened and closed via a cam mechanism installed on a movable guide tube on the lower guide tube side. An application has already been filed by a person (Japanese Unexamined Patent Publication No. 1408941/1983). Next, the configuration of the above fuel exchanger is shown in Figures 5 to 8.
This will be explained with reference to the diagram. First, in FIGS. 5 and 6, reference numeral 1 indicates a pressure vessel of a fuel exchanger mounted on a traveling truck (not shown). A rotating drum type magazine assembly 3 equipped with a plurality of magazine tubes 2 is housed. On the other hand, above the magazine assembly 3 in the center, an upper guide tube 4 with a snout and a gripper guide tube 5 with a port valve are arranged opposite to the magazine tube row, and below it is a fixed guide tube 6. A lower guide tube combining a movable guide tube 7 and a grab guide tube 9 housing a grab mechanism 8 are each pulled out from the pressure vessel 1 and installed. Each magazine tube 2 constituting the magazine assembly 3 is equipped with an opening/closing type magazine stopper mechanism 10 at its lower end, the detailed structure of which will be described later. A cam mechanism 11 for opening/closing the magazine stopper mechanism is mounted on the upper end of the movable guide tube 7 on the opposite side. Further, a cylinder for driving up and down, indicated by reference numeral 12, is connected to the movable guide tube. The above-mentioned magazine stopper mechanism 10 supports the weight of the fuel 13 etc. stored in the magazine tube 2 and holds it in the magazine tube, and when the fuel 13 is carried in and out through the lower guide pipe by operating the gripper. In this case, the stopper mechanism 10 of the magazine tube communicating with the lower guide pipe 6 is opened to allow fuel to pass through. Here, to explain the procedure for exchanging fuel with the above configuration, first connect the snout to the pressure pipe of the reactor, and by lifting and lowering the grab 8 and rotating the magazine assembly 3, the used fuel is pulled out from the pressure pipe side. Core components such as fuel are drawn into the magazine tube 2, and new fuel previously stored and held in another magazine tube is loaded into the pressure tube instead. In addition, in this state, the magazine stopper mechanism 1
0 is closed, and in this state, only the grab 8 freely passes through the remaining passage inside the stopper mechanism and is operated up and down. When the fuel exchange work with the reactor is completed in this way, the fuel exchange machine moves to another fuel delivery position, and at this position connects the port of the lower guide pipe 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 5 to grasp the spent fuel 13 housed in the magazine tube. Subsequently, the magazine stopper mechanism 10 provided in the magazine tube is opened, and the gripper is operated to lower the spent fuel to the transport equipment side through the lower guide pipes 6 and 7 and carry it out. Conversely, when carrying in fuel, the new fuel is drawn into the magazine tube in the reverse order 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.
Fuel is held within the magazine tube. Next, the structure and operation of the magazine stopper mechanism and its opening/closing operation mechanism in the fuel exchanger having the above structure will be explained with reference to FIGS. 7 and 8. In FIGS. 7 and 8, the magazine stopper mechanism 10 includes a housing 14 attached to the lower end of the magazine tube 2, a sliding horizontal shutter plate 15 disposed on both left and right sides within the housing 14, and a shutter plate 15. The shutter plate 15 is assembled with a biasing spring 16 that biases the plate 15 to protrude into the fuel passage from behind, and the shutter plate 15 has guide pins 17 extending laterally from both sides thereof cut into the side surfaces of the housing 14. It passes through a cut-out horizontal long groove 10a and is guided and supported so as to be slidable in the horizontal direction of arrow A. On the other hand, a cam mechanism 11 for opening and closing the magazine stopper mechanism is provided at the upper end of the movable guide tube 7 facing the magazine stopper mechanism 10, and the cam mechanism 11 is provided with a cam mechanism 11 facing the guide pin 17. As shown by reference numeral 18, a guide cam groove having a bent shape is formed at a midway point. Next, the operation of the above configuration will be explained. First, as shown in the figure, when the movable guide tube 7 is in the lowered position, the magazine stopper mechanism 10 and the cam mechanism 11 are separated from each other, and the magazine assembly is
The shutter plate 15 is not restricted by the cam mechanism 11 and can rotate freely without interference with the spring 1.
6, it protrudes into the fuel passage and holds the stopper mechanism in the closed position. When the movable guide tube 7 is raised from this state by driving the cylinder 12 shown in FIG. 5, the cam mechanism 11 moves upward together with the movable guide tube 7, and the magazine stopper mechanism
The guide pin 17 on the shutter plate side comes to fit into the guide cam groove 18. Subsequently, as the movable guide tube rises further, guide pin 1
7 is forcibly guided along the guide groove 18 of the cam mechanism 11, and the shutter plate 15 moves backward against the biasing spring 16 to open the stopper mechanism. In this state, fuel can freely pass between the magazine tube 2 and the movable guide tube 7. Furthermore, when the movable guide tube 7 is lowered again after the fuel carrying-out and carrying-in operations are completed, the shutter plate 15 is guided in the opposite direction to close along the guide groove 18 of the cam mechanism 11, and the magazine stopper mechanism 10
When the coupling with the cam mechanism 11 is released, the magazine stopper mechanism is held in the closed position by the biasing force of the biasing spring 16, and the series of opening and closing operations of the magazine stopper mechanism is completed. Note that the opening/closing stroke of the shutter plate 15 in the above operation is indicated by S. By the way, the above-mentioned magazine stopper mechanism 10
In a state where the shutter plate 15 retains the fuel contained in the magazine tube 2, it is required that the shutter plate does not open even if a command to open the magazine stopper mechanism is given by mistake. Otherwise, the fuel stored in the magazine tube may unexpectedly fall off and cause an accident. For this reason, in the magazine stopper mechanism described above, as shown in FIG.
A mechanical interlock is formed by providing an engaging protrusion indicated by a. This engaging protrusion 15a is such that when the fuel 13 is suspended and supported on the shutter plate 15, the lower end peripheral edge of the fuel 13 is
5a, and as long as the fuel 13 and the engagement protrusion 15a of the shutter plate are properly engaged in this way, even if an opening command is given to the magazine stopper mechanism by mistake, the shutter plate 15 will not move. Since it is engaged with the fuel 13, it does not open, thereby preventing the occurrence of an accident in which the fuel falls off. On the other hand, the inner diameter of the magazine tube 2 described above is determined by the fuel as a core component accommodated here.
It is set to match the shielding seal plug with a large diameter among the shielding seal plugs, and is approximately 20 mm larger than the diameter of the fuel. Therefore, the magazine tube 2 has a guiding function for the large-diameter shielding seal plug when it passes through the tube, but for small-diameter fuel, a gap remains between the fuel and the inner wall surface of the magazine tube. Therefore, the guide function cannot be demonstrated. For this purpose, the fuel is lifted up and carried into the empty magazine tube from the fuel conveyance equipment outside the machine, and the fuel is lifted into the tube during the work process when closing the shutter plate 15 of the magazine stopper mechanism and lowering the fuel onto it. If the fuel 13 is eccentric from the center, the landing position of the fuel will be tilted as shown by the chain line in FIG. .
In such a supported state, the mechanical interlock function does not work, and if an opening command is given to the magazine stopper mechanism 10 by mistake, the shutter plate 15 will open and the stored fuel 13 in the magazine tube will open.
There is a risk that the magazine tube 2 may unexpectedly fall off from the magazine tube 2.

[Purpose of the invention]

This invention has been made in consideration of the above points, and has been developed by improving the above-mentioned fuel exchanger to provide a centering guide so that the fuel comes to the center of the magazine tube when storing small-diameter fuel in the magazine tube. An object of the present invention is to provide a fuel exchanger equipped with a centering guide function in which the mechanical interlock function between the shutter plate and the fuel can be reliably performed in a state where the fuel lands on the shutter plate.

[Key points of the invention]

In order to achieve the above object, the present invention provides a centering guide mechanism that operates to center the stored fuel within the magazine tube, using the tip of a movable guide tube facing the magazine stopper mechanism as an actuator, at a midway point in the magazine tube. With this, when carrying small-diameter fuel into the magazine tube, the fuel is centered and guided within the magazine tube, and the fuel lands at a predetermined position on the shutter plate of the magazine stopper mechanism, ensuring a secure flow between the two. This allows the mechanical interlock function to be demonstrated.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 4. Note that in FIGS. 1 to 4, the same members corresponding to FIGS. 5 to 8 are given the same reference numerals. First, the overall configuration of the fuel exchanger and the structure of the magazine stopper mechanism are as follows.
The structure is similar to that shown in FIGS. 8 through 8, and newly added components according to the present invention will be explained here. That is, according to the present invention, the magazine stopper mechanism 10 in the magazine tube 2
A centering guide mechanism designated by reference numeral 20 is constructed above the . This centering guide mechanism 20 has ball grooves 21 opened in at least three locations selected along the circumference of the magazine tube 2 so as not to interfere with the magazine stopper mechanism 10, and a centering guide mechanism 20 in which ball grooves 21 are opened in at least three locations. The centering ball 22 is pushed into the inner circumferential side of the magazine tube 2 by fitting the ball 22 and lifting the movable guide tube using the distal end 7a of the movable guide tube 7 as an actuator. That is, the centering ball 22 moves toward the inner and outer peripheries within the ball groove 21 in the direction of arrow C.
It is inset and set so that it can move freely in any direction. However, the inner and outer open ends of the ball groove 21 have hole diameters smaller than the diameter of the centering ball 22 to prevent the centering ball 22 from falling out of the ball groove 21. On the other hand, the movable guide tube 7 faces the centering ball 22.
On the side, a vertical ball relief groove 7b for releasing the restraint of the centering ball 22 is formed in the lower region of the actuator portion 7a at the tip. Furthermore, as shown in FIG.
The shutter plate 15 of the magazine stopper mechanism 10 is stopped in the closed position in the X area, and the shutter plate 15 of the magazine stopper mechanism 10 is moved to the open position in the Z area. It is formed to connect in the area. Next, the operation and function of the above configuration will be described. First, FIG. 1 shows a standby state in which the magazine stopper mechanism 10 and the movable guide tube 7 are separated. In this state, the shutter plate 15 of the magazine stopper mechanism 10 is closed, and the centering guide mechanism 20 is closed. The centering ball 22 is in a state where it can move freely within the ball groove 21 without restriction. On the other hand, in Fig. 2, the fuel 13 is transferred to the magazine tube 2.
The centering guide is shown within the center. That is, in this state, the movable guide tube 7 is lifted and fitted into the outer periphery of the magazine tube 2, and its tip 7a pushes the centering ball 7a from the outer periphery and projects inward toward the center of the magazine tube 2. At this position, the small-diameter fuel 13 housed in the magazine tube 2 is centered and guided to the center of the tube. At this stage, the shutter plate 15 of the magazine stopper mechanism 10 is aligned with the X of the guide cam groove 18 shown in FIG.
The shutter plate 15 is in a closed state. Next, FIG. 3 shows that the movable guide tube 7 is further raised from the state shown in FIG. It shows the condition. In this state, the ball relief groove 7b on the movable guide tube 7 side faces the centering ball 22 of the centering guide mechanism, and the restraint of the centering ball 22 is released.
Therefore, the centering ball 22 is located in the ball groove 2.
Can move freely within 1. Next, based on the operating conditions shown in Figures 1 to 3 above, we will explain the procedure for transporting fuel and shielding seal plugs between the fuel exchange machine and the external fuel transfer equipment. I will explain the plugs separately. (1) When carrying in fuel, firstly, when carrying in the fuel 13 by drawing it into the empty magazine tube 2 through the lower guide pipe 6 in Fig. 5, the movable guide pipe 7 is
3 to open the shutter plate 15 of the magazine stopper mechanism 10 and secure a fuel passage leading into the magazine tube 2. In the next step, a fuel handling machine lifts and draws the fuel into the magazine tube through the lower guide pipe. Once the fuel 13 has been lifted above the centering ball 22, the movable guide tube 7 is slightly lowered to set the state shown in FIG. Note that in this state, the shutter plate 15 is closed. Next, when the fuel is lowered into the magazine tube by the fuel handling machine, during this process, the fuel 13 is centered and guided by the centering ball 22 protruding from the inner circumference of the magazine tube, and the fuel 13 is guided to the magazine stopper mechanism 10. It lands on the shutter board 15. Therefore, as shown in FIG.
When properly engaged, mechanical interlock is established. When this process is completed, the movable guide tube 7 is finally lowered to the standby position shown in FIG. 1, and the series of fuel storage operations is thus completed. (2) When carrying in the shielding seal plug, the diameter of the shielding seal plug is larger than that of the fuel as described above, and its outer diameter is approximately equal to the inner diameter of the magazine tube 2, and in this case, the centering guide described above Function is not required. Therefore, the procedure for drawing the shielding seal plug into an empty magazine tube is as follows. First, the movable guide tube 7 is raised from the standby position shown in FIG. 1 to the state shown in FIG. 3 to open the magazine stopper mechanism 10, 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 2 by lifting the fuel handling machine. At this time, even if the centering ball 22 protrudes toward the inner periphery of the magazine tube, the centering ball 22 is not restrained, so the shielding seal plug can freely rise within the magazine tube. Here, lift the shielding seal plug so that the lower end is further above the position of the centering ball 22, then lower the movable guide tube 7 to return to the state shown in FIG.
Close the shutter plate 15. During this return process, the centering ball 22 temporarily protrudes toward the inner periphery of the magazine tube as the state shown in FIG. Since it is pushed by the seal plug and retracted toward the outer circumference, it does not cause any obstruction. Finally, attach the shielding seal plug to the shutter plate 15 of the magazine stopper mechanism.
The work of carrying it into the magazine tube is completed by landing it on top.

【Effect of the invention】

As described above, according to the present invention, a centering guide mechanism is installed in the middle of the magazine tube and operates to center the stored fuel within the magazine tube by using the tip of the movable guide tube as an actuator. When transporting a fuel magazine tube whose diameter is smaller than that of the magazine tube from the fuel transfer equipment outside the aircraft,
During the loading process, the fuel is centered and guided within the magazine tube, allowing it to land correctly on the shutter plate of the magazine stopper mechanism at the designated position. It is possible to reliably utilize the mechanical interlock function and prevent fuel from falling or dropping due to erroneous operation, thereby improving reliability.

[Brief explanation of drawings]

1 to 4 show the main parts of a fuel exchanger according to an embodiment of the present invention, FIGS. 1 to 3 are explanatory diagrams of different operating states of the centering guide mechanism, and FIG. A configuration diagram of the magazine stopper mechanism, FIG. 5 is a cross-sectional view of the overall configuration of the fuel exchanger to which the present invention is applied, FIG. 6 is a cross-sectional view taken in the direction of the arrow in FIG. 5, and FIG. 7 is a conventional magazine stopper mechanism. 8 is a cross-sectional view taken in the direction of the arrow in FIG. 7, FIG. 9 is a diagram showing a state in which the fuel and the engaging protrusion of the shutter plate are engaged, and FIG. 10 is a diagram showing the fuel shutter plate. It is a figure which shows the state which the engagement with the engagement protrusion part of was disengaged. In the figure, 2:
Magazine tube, 3: Magazine assembly, 6: Lower guide tube, 7: Movable guide tube, 7a: Tip part as actuator, 7b: Ball relief groove, 10:
Magazine stopper mechanism, 11: Cam mechanism, 13:
Fuel, 15: Shock plate, 15a: Engagement protrusion for mechanical interlock, 18: Guide cam groove,
20: Centering guide mechanism, 21: Ball groove, 22: Centering ball.

Claims (1)

[Claims] 1. A rotary drum type magazine assembly consisting of a plurality of fuel storage magazine tube mechanisms equipped with a magazine stopper mechanism at the lower end, with piping arranged above and below the magazine assembly, sandwiching the magazine assembly. This is a fuel exchange machine that exchanges fuel with the reactor and transfers fuel with external fuel transfer equipment through each combustion guide pipe, and also has a part of the lower guide pipe facing the magazine stopper mechanism. The vertically movable guide tube is equipped with a cam mechanism for opening and closing the magazine stopper mechanism, and the shutter plate of the magazine stopper mechanism is opened and closed via the cam mechanism by raising and lowering the movable guide tube. A fuel exchange machine for a pressure tube nuclear reactor, characterized in that a centering guide mechanism is installed in the middle of the magazine tube, using the tip end of the movable guide tube as an actuator, and operates to center the contained fuel in the magazine tube. 2. In the fuel exchanger according to claim 1, the centering guide mechanism has a centering ball that is removably inserted into a ball groove that is distributed and opened on the circumferential surface of the magazine tube, A fuel exchanger for a pressure tube nuclear reactor, characterized in that the distal end of a movable guide tube is pushed in from the outer periphery of a magazine tube and protruded toward the inner periphery to center and guide the stored fuel. 3. In the fuel exchanger according to claim 2, on the movable guide tube side opposite to the centering ball on the magazine tube side, the centering ball is restrained at the raised position of the movable guide tube that releases the magazine stopper mechanism. A fuel exchanger for a pressure tube nuclear reactor, characterized in that it is equipped with a release ball relief groove.