JPH027040B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a repair seal plug that is loaded deep inside the pressure pipe instead of a regular seal plug when repairing the opening end sealing surface of the pressure pipe in a pressure tube nuclear reactor. This invention relates to a method for handling the fuel exchanger by a grab operation.

As is well known, in the pressure tube reactor mentioned above, a seal plug is installed at the open end of the pressure tube to form a pressure boundary for the primary coolant sealed in the pressure tube when fuel is loaded. . Such a seal plug is handled by a grab operation of a fuel exchanger when exchanging fuel, and is attached to and detached from a pressure pipe.
That is, in FIG. 1, reference numeral 1 indicates a pressure pipe constituting the reactor core, and reference numeral 2 indicates a fuel exchanger running below the reactor. As detailed in FIG. 2, inside the pressure pipe 1, during normal furnace operation, there are fuel assemblies 3,
The sealing body 4 and the sealing plug 5 are inserted in a mutually connected state, and the sealing plug 5 is connected to the open end of the pressure tube 1 via a ball-type latch mechanism 6, and is further connected to the tube wall of the pressure tube 1. The seal body is in close contact between the two to form a seal. On the other hand, as is well known, the fuel exchanger 2 is equipped with a snout 10 on the top of a pressure vessel 9 mounted on a traveling truck 8, which is fluid-tightly connected to the lower end of the pressure pipe 1. Various equipment such as a snout drive system that is not used, a magazine that accommodates fuel assemblies, a magazine drive system, a glove that grips the seal plug, a lift drive system for the grab, and a grab operation system are stored vertically. As for the fuel exchange procedure, first, snout 1
0 connected to the lower end of the pressure pipe 1, the glove is raised by the elevating drive system, guided into the pressure pipe through the magazine and the snout, and is connected to the seal plug 5 described above.
combine with Next, after the seal plug 5 and the pressure pipe 1 are uncoupled by a grab operation, the grab is driven downward, and the shield body 4 and fuel assembly 2 are drawn into the pressure vessel 9 and stored in the magazine. In addition, for loading new fuel, new fuel previously stored in a separate magazine is inserted into the pressure pipe 1 in the reverse procedure to the above.
In FIG. 2, the reference numeral 11 designates a latch sleeve of the ball latch mechanism 6 which is operated by a glove, and the reference numeral 12 designates an actuator for disengaging the seal body 7 which is also operated by an actuator on the glove side.

On the other hand, in the above-mentioned pressure tube type nuclear reactor, the globules generated in the reactor as the operation progresses settles in the pressure tube 1 and adheres to the sealing surface between the seal body 7 of the seal plug 5 and the pressure tube 1. As a result of repeated attachment and detachment of the seal plug 5, the sealing surface gradually becomes rough during long-term operation, resulting in a decrease in sealing performance. In this case, the integrity of the seal body 7 on the seal plug side can be easily maintained by periodically replacing it with a new one, but the seal surface on the pressure pipe side cannot be replaced with a new one, and the furnace cannot be operated properly. When the system is stopped, it is necessary to carry out repair work to flatten the rough seal surface of the pressure pipe 1 with the fuel assembly, seal plug, etc. removed. However, when repairing the lever pressure pipe,
In order to seal the primary coolant in the reactor and to protect against radiation, a repair seal plug is used in place of the regular seal plug, and it is placed further away from the sealing surface so as not to block the sealing surface inside the pressure pipe. It needs to be inserted deep inside and installed. In this case, if the repair seal plug were to be handled by directly grasping it with the glove of the fuel exchanger shown in Figure 1 in the same way as the regular seal plug, it would be obvious that the required lifting stroke of the glove would be longer than that of the regular seal plug. This is larger than the lifting stroke required when handling plugs. In addition, as the required lifting stroke of the grab increases, a longer grab is required on the fuel exchange machine side, and in order to store this long grab below the magazine in the pressure vessel, the fuel exchange machine needs to have a longer grab. The pressure vessel inevitably becomes longer. Furthermore, the height of the building that constitutes the fuel exchange room will also increase. In other words, in order to repair the sealing surface of a pressure pipe that is only performed every few years or decades, it is necessary to configure the fuel exchanger to be large enough to accommodate the stroke required to operate the repair seal plug. This increases the burden and is economically disadvantageous.

Regarding this point, if a short fuel exchanger configured to handle regular seal plugs could be used as is, and a repair seal plug could be inserted to the predetermined loading position when repairing a pressure pipe, this would solve the problem. The benefits in terms of equipment that can be obtained are extremely large.

This invention was made in consideration of the above points, and its purpose is to repair a repair seal plug loaded when repairing the seal surface of a pressure pipe using the same grab stroke operation of a fuel exchange machine as when handling a regular seal plug. To provide a new method for handling a repair seal plug that can be inserted into a predetermined position in a pipe and then mounted without blocking the sealing surface.

According to the present invention, the present invention provides a repair seal plug which is equipped with a seal body and a latch mechanism that connects to a pressure pipe, and which includes an adapter body sized to be inserted into the pressure pipe, and a rear end of the adapter body formed at the rear end of the adapter body. a latch mechanism configured at the tip of the adapter body for connecting the repair seal plug and the pressure pipe; and a latch mechanism movably disposed through the adapter body and the fuel exchanger. A stroke operation is performed by a grab operation to engage and release the latch of the latch mechanism for coupling the pressure pipe and the repair seal plug, and to engage and disengage the latch of the latch mechanism for coupling the repair seal plug side collar to the adapter body. A grab adapter consisting of a latch operating rod for engaging and disengaging is housed in the pressure pipe on the side of the fuel exchanger, and with the grab adapter attached to the glove of the fuel exchanger, the latch operating rod is operated by the grab. This is achieved by moving the repair seal plug up and down to load and unload the repair seal plug into and out of the pressure pipe.

Embodiments of the present invention will be described in detail below based on the drawings.

Figure 3 shows the loading state of the repair seal plug inserted into the pressure pipe when repairing the seal surface, and Figures 4 and 5 show the attachment and detachment operation of the repair seal plug. First, in Figure 3, 13 is a repair seal plug, 14 is the repair seal plug 13
The part indicated by the symbol P indicates the seal surface on the pressure pipe side that contacts the seal body 7 of the regular seal plug 5 shown in FIG. 2, that is, the repair location. The repair seal plug 13 is loaded at a position further inside the pipe than the position of the seal surface P so as not to become an obstacle to repair work on the seal surface P, and the seal body attached to the outer periphery of the seal plug 13 15 is in close contact with the wall of the pressure pipe 1 to seal the primary coolant, and is connected to the pressure pipe via a ball latch mechanism 16. By the way, according to the present invention, a grab adapter 17 as shown in FIGS. 4 and 5 is prepared for the above-mentioned repair seal plug 13, and after the grab adapter 17 is attached to the glove of the fuel exchanger, The repair seal plug 13 is loaded and pulled out.

Next, the detailed structure of the repair seal plug 13 and the grab adapter 17 will be described with reference to FIG. First, in the seal plug 13, an O-ring is adopted as the seal body 15, and is fitted into the outer peripheral groove of the plug body. The ball latch mechanism 16 is composed of a ball 18, a piston-shaped actuator 19, and a biasing spring 20. In the loading position, the ball 18 is pushed by the actuator 19 biased by the spring and fits into the ball groove 21 on the pressure pipe side, sealing the ball. A plug 13 is connected to the pressure tube 1. On the other hand, grab adapter 1
Reference numeral 7 includes an adapter body 17a having a size to be inserted into the pressure pipe 1, and the rear end of the adapter body 17a is not shown in exactly the same manner as the regular seal plug 5 shown in FIG. The ball groove 22 is connected to a latch ball on the glove side of a well-known fuel exchanger, and the tip thereof is equipped with a ball latch mechanism for connecting the seal plug 13, which is composed of a ball 23 and a latch operating rod 24. The latch operating rod 24 also serves to release the ball latch mechanism 16 on the seal plug side, and passes vertically through the adapter body 17a, with a ball groove 25 formed at its rear end to be connected to the actuator on the glove side. and is biased downward by a spring 26. The length dimension of the grab adapter 17 is selected so that the position of the ball groove 22 in the inserted state shown in FIG. 4 is exactly the same as the ball groove of the regular seal plug shown in FIG.

Next, the handling operation of the repair seal plug with the above configuration will be described. FIG. 4 shows a state in which the grab adapter 17 is attached to the tip of the glove of the fuel exchanger 2 shown in FIG. 1 and inserted into the pressure pipe 1 in order to pull out the loaded repair seal plug 13 from the pressure pipe 1. 5 shows a state in which the seal plug 13 and the pressure pipe 1 are uncoupled by a grab operation from the position shown in FIG. 4, and at the same time, the seal plug 13 and the grab adapter 17 are connected and connected by a grab operation. That is, when the seal plug 13 for repair is to be taken out after the seal surface repair action of the pressure pipe 1 is completed, the grab adapter 17 that was removed from the pressure pipe and stored in the magazine of the fuel exchanger during the repair work is first removed. Grasp it with a glove, drive the glove upward, and insert it into the pressure pipe to the position shown in Figure 4. From here, when the actuator on the grab side is operated and the latch operating rod 24 is pushed upward against the spring 26 as shown in Fig. 5, the actuator 19 on the seal plug side rises against the spring 20, causing a Eventually, the ball 18 retreats from the ball groove 21 on the pressure tube side, and at the same time, the ball 23 on the adapter side is pushed out and comes to engage with the collar 27 at the lower end of the seal plug 13. If the grab is driven downward while maintaining this state, the grab adapter 17 and seal plug 1
3 and the shingle shield body 14 shown in FIG. 3 are subsequently recovered into the pressure vessel of the refueling machine. Furthermore, in order to load the seal plug 13 and the shield body 14 into predetermined positions within the pressure pipe prior to repairing the seal surface P, the procedure is reversed to that described above, and the plugs are inserted into the pressure pipe from the fuel exchange side. After the seal plug 13 is set in a predetermined position, the latch operating rod 24 is returned to disconnect the seal plug 13 and the grab adapter 17, and then the grab adapter 17 alone and the glove are pulled out from the pressure pipe 1 and removed. be done. That is, the above-mentioned repair seal plug 13
The lifting and lowering stroke movement of the grab when loading and unloading is performed using the regular seal plug 5 shown in Figure 2.
This will be done in exactly the same way as when handling.

As described above, the present invention provides a grab adapter for a repair seal plug in advance and stores it in a fuel exchanger together with the repair seal plug, and when repairing the seal surface of a pressure pipe, the glove adapter is attached by a grab operation when repairing the seal surface of a pressure pipe. The repair seal plug can be removed, loaded, and taken out via the adapter, so there is no need to make the fuel exchanger a special elongated structure to suit the handling conditions of the repair seal plug. While using a short refueling machine configured to meet the conditions for handling regular seal plugs, repair seal plugs can be inserted into or removed from a predetermined position within a pressure pipe, thereby reducing equipment costs. You can get a big implementation in.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of fuel exchange equipment for a pressure tube reactor, Fig. 2 is a sectional view showing how a regular seal plug is loaded in the pressure pipe, and Fig. 3 is a seal plug for repair according to the present invention, which is loaded in the pipe. A cross-sectional view showing the condition,
FIGS. 4 and 5 are sectional views of essential parts showing the state of disconnection and connection of the repair seal plug and the grab adapter at the loading position in the pressure pipe according to the embodiment of the present invention, respectively. 1... Pressure pipe, 2... Fuel exchange machine, 3... Fuel assembly, 5... Regular seal plug, 13... Seal plug for repair, 15... Seal body, 16... Latch mechanism for coupling with pressure pipe, 17... Grab adapter , 17a
...adapter body, 22...ball groove for coupling with the glove, 23...latch ball for coupling with the seal plug, 24...latch operating rod, P...sealing surface of the pressure pipe to be repaired.

Claims (1)

[Claims] 1. When repairing the seal surface on the pressure pipe side that contacts the regular seal plug attached to the open end of the pressure pipe,
This is a handling method in which a repair seal plug, which is inserted deeper into the pipe than the position of the repair surface in place of the regular seal plug described above, is installed and removed by a grab operation of a fuel exchanger, and the seal plug and the pressure pipe are a repair seal plug equipped with a latch mechanism for coupling with a repair seal plug, a coupling portion between an adapter body sized to be inserted into the pressure pipe and the glove formed at the rear end of the adapter body; A latch mechanism for connecting the repair seal plug and the pressure pipe is configured at the tip of the adapter body, and a latch mechanism is movably disposed through the adapter body and is stroke operated by the grab operation of the fuel exchanger to adjust the pressure. It consists of a latch operating rod that engages and disengages the latch of the latch mechanism for coupling between the pipe and the repair seal plug, and the latch of the latch mechanism for coupling between the collar on the repair seal plug side and the adapter body. A grab adapter is housed in the pressure pipe on the side of the fuel exchanger, and with the grab adapter attached to the glove of the fuel exchanger, the latch operation rod is moved up and down by the grab operation, and the latch operation rod is moved up and down by the grab operation. Loading the seal plug into the pressure pipe,
A method for handling a repair seal plug used when repairing a pressure pipe of a pressure tube nuclear reactor, characterized in that it is adapted to be taken out.