In-containment inspection work apparatus for nuclear reactor

Abstract

To enable an inspection work apparatus alone to move between the inside and outside of a reactor containment vessel without using a door, while restricting movement of suspended matter within the reactor containment vessel.SOLUTION: An in-containment inspection work apparatus for a nuclear reactor 28 is used for inspection work within a reactor containment vessel 1 accommodating a reactor pressure vessel 17 is characterized in that the reactor containment vessel 1 is connected to a pipe 26 for connecting a reactor building 3 accommodating the reactor containment vessel 1 and the inside of the reactor containment vessel 1 and allowing an inspection work apparatus 16 to be introduced via a water seal device 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an inspection work apparatus for the inside of a reactor containment vessel in a nuclear power plant after a severe accident. [Background technology]

[0002] In nuclear power plants after a severe accident such as a core meltdown, radioactive materials exist inside the reactor containment vessel. To prevent this radioactive material from dispersing into the atmosphere, the walls of the reactor containment vessel are the main barrier. Hereafter, the boundary that confines airborne materials that need to be prevented from leaking or flowing in between the work space and the outside world is called the boundary.

[0003] On the other hand, when entering the containment vessel with equipment for removing melted fuel debris and remotely operated inspection and work equipment for investigating the state of the vessel interior in preparation for decommissioning, it is necessary to maintain the boundary. Specifically, it is necessary to somehow connect the inspection and work equipment storage facility to the containment vessel barrier, and to continue maintaining the boundary state throughout the entire process from the inspection and work equipment entering, working, retrieving, and isolating the inspection and work equipment storage facility.

[0004] FIG. 6 is a schematic cross-sectional view of the reactor building 3 showing the internal boundary structure of the reactor containment vessel 1.

[0005] As shown in Figure 6, it is necessary to enter an inspection work device (not shown) to prevent floating material 2 in a reactor containment vessel 1 that houses a reactor pressure vessel 17 from flowing into a reactor building 3. The boundary structure for this purpose is a primary boundary 4 and a secondary boundary 5 installed outside the primary boundary 4, with a door 6 on the primary boundary 4 and a door 7 on the secondary boundary 5.

[0006] When the inspection work equipment is to enter, the door 6 of the primary boundary 4 and the door 7 of the secondary boundary 5 are opened and closed separately to allow the equipment to enter from the secondary boundary 5 into the primary boundary 4. By using this method, one of the two doors is always closed when an object enters or leaves, which prevents direct connection between the reactor containment vessel 1 and the atmosphere. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-117491 Summary of the Invention [Problem to be solved by the invention]

[0008] In the example of the inspection work equipment inside the reactor containment vessel 1 shown in Figure 6, when the inspection work equipment enters the reactor containment vessel 1, two doors 6 and 7 must be opened and closed in sequence. After confirming that one door is completely closed, the other door must be opened, and these controls are complex. As a result, there is a possibility of human error occurring, such as opening one door before the other door is completely closed. [Means for solving the problem]

[0009] The inspection work device inside a reactor containment vessel according to the above embodiment is an inspection work device inside a reactor containment vessel used for inspection work inside a reactor containment vessel that contains a reactor pressure vessel, and is characterized in that it communicates with a reactor building that houses the reactor containment vessel and that piping for inserting the inspection work device is connected to the reactor containment vessel via a water seal. [Effects of the Invention]

[0010] The embodiment of the present invention has been made to solve the above-mentioned problems, and the water seal restricts the movement of suspended matter inside the reactor containment vessel, while allowing inspection work equipment to move inside and outside the reactor containment vessel without using a door. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view of an inspection work device for inside a containment vessel according to the present invention; [Figure 2] FIG. 3 is a schematic cross-sectional view showing a second embodiment of the reactor containment vessel inside inspection work device according to the present invention. [Figure 3] FIG. 4 is a schematic cross-sectional view showing a third embodiment of the reactor containment vessel inside inspection work device according to the present invention. [Figure 4] FIG. 10 is a schematic cross-sectional view showing a fourth embodiment of the reactor containment vessel inside inspection work device according to the present invention. [Figure 5] FIG. 10 is a schematic cross-sectional view showing a fifth embodiment of the reactor containment vessel inside inspection work device according to the present invention. [Figure 6] FIG. 1 is a schematic cross-sectional view of a reactor building showing the internal boundary structure of a reactor containment vessel. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Example 1 The structure of a reactor containment vessel inside inspection work device 28 according to the present invention will be described with reference to the schematic cross-sectional view of Fig. 1. In Fig. 1, the same parts as those in Fig. 6 are given the same reference numerals, and description of the configuration of those parts will be omitted.

[0014] In FIG. 1, in order to introduce inspection work equipment 16 into the reactor containment vessel 1 from the outside, a pipe 26 that connects the reactor building 3 that houses the reactor containment vessel 1 with the reactor containment vessel 1 and that allows the inspection work equipment 16 to be introduced is arranged in the reactor containment vessel 1 via a water seal 8 that stores a liquid such as water inside.

[0015] A partition plate 10 is placed from above on rectangular piping 9 that constitutes this water seal device 8, and the liquid is stored forming a water surface above the lower end of the partition plate 10, with a flow path at the bottom, and this structure is equipped with a piping inlet 11 and a piping outlet 12. The piping outlet 12 is connected via a joint 13 to a through hole 14, for example, by welding or bolting via a flange, or clamping, and leads to an input space 15 that is closed within the reactor containment vessel 1. On the other hand, the piping inlet 11 leads to an initial placement space 27 for an inspection work device 16 that has, for example, an inspection robot, an endoscope, a manipulator, etc., that is to be operated within the input space 15.

[0016] Here, the input space 15 in FIG. 1 is represented as a closed space, such as a container, but it may be open to the atmosphere. Here, to prevent communication between the initial placement space 27 and the input space 15 via the rectangular pipe 9 with the partition plate 10, a water sealing liquid, such as water, is injected from a tank through the water inlet 18 using, for example, a pump or gravity, into the water seal device 8, filling the interior of the rectangular pipe 9 with the partition plate 10. The liquid introduced into the water seal device 8 may be a liquid such as oil or mercury that does not affect the testing operation or testing environment. The water level introduced into the water seal device 8 is adjusted so that it does not leak from the pipe inlet 11 and the pipe outlet 12. The water level is adjusted by injecting water through the water inlet 18 and draining it through the drain outlet 19 using, for example, a pump or gravity.

[0017] When the inspection work device 16 passes through the rectangular pipe 9 with the partition plate 10, the liquid in the rectangular pipe 9 with the partition plate 10 in the water seal device 8 blocks the floating material 2 floating in the reactor containment vessel 1 so that it does not flow into the initial placement space 27. This blocking continues as long as the water level in the water seal device 8 is maintained while the inspection work device 16 is working inside the reactor pressure vessel 17, and even after the inspection work device 16 returns from the insertion space 15 to the initial placement space 27 after the work is completed.

[0018] Therefore, in this embodiment, the water seal 8 restricts the movement of suspended matter 2 inside the reactor containment vessel 1, while allowing only the inspection work device 16 to move between the inside and outside of the reactor containment vessel 1 without using a door.

[0019] Example 2 2 is a schematic cross-sectional view showing a second embodiment of an inspection device 28 for inspecting inside a containment vessel according to the present invention. In FIG. 2, the same parts as those in FIG. 1 are given the same reference numerals, and a description of the configuration of those parts will be omitted.

[0020] In the second embodiment, the reactor containment vessel inside inspection work device 28 described in the first embodiment is configured such that a foreign matter recovery mechanism 20 is connected to the piping outlet 12 as shown in FIG.

[0021] If foreign matter 21, such as processing aids or waste liquids used for processing work inside the pipe, occurs inside the pipe after the pipe outlet 12, the foreign matter 21 may obstruct the passage of the inspection work device 16. In this case, the foreign matter 21 is sent toward the pipe inlet 11 by another inspection work device 16 that is one size smaller, such as a small cleaning device that reverse-sprays water and moves forward using the reaction force.

[0022] However, if left in this state, there is a risk that the foreign matter will accumulate in the rectangular pipe 9 with the partition plate 10 or that the water level will change. Therefore, by connecting the foreign matter collection mechanism 20 to the pipe outlet 12, the foreign matter 21 passing through the foreign matter collection mechanism 20 will fall by gravity, and the foreign matter 21 can be collected by gravity or by a suction device (not shown) before it flows into the rectangular pipe 9 with the partition plate 10.

[0023] Therefore, in this embodiment, foreign objects 21 that obstruct the passage of the inspection work equipment 16 can be quickly collected, and the water seal 8 restricts the movement of floating matter 2 inside the reactor containment vessel 1, while allowing the inspection work equipment 16 to easily move inside and outside the reactor containment vessel 1 without using a door.

[0024] Example 3 3 is a schematic cross-sectional view showing a third embodiment of an inspection device 28 for inspecting inside a containment vessel according to the present invention. In FIG. 3, the same parts as those in FIG. 1 and FIG. 2 are designated by the same reference numerals, and a description of the configuration of those parts will be omitted.

[0025] In this third embodiment, the reactor containment vessel inside inspection work device 28 described in the first and second embodiments is configured such that a vent mechanism 22 with a filter is attached to the piping outlet 12 as shown in FIG.

[0026] If the internal pressure rises in the piping on the side of the containment vessel 1 after the piping outlet 12, the liquid in the rectangular piping 9 with the partition plate 10 may flow into the piping inlet 11, causing the water level to change from that adjusted in Example 1. For this reason, the installation of a vent mechanism 22 reduces the internal pressure of the piping 26 while removing the suspended solids 2 with a filter.

[0027] Therefore, in this embodiment, even if the internal pressure rises in the piping on the reactor containment vessel 1 side, the internal pressure of the piping 26 can be reduced by the vent mechanism 22 with a filter, maintaining the function of the water seal 8 and restricting the movement of suspended matter 2 inside the reactor containment vessel 1, while allowing the inspection work device 16 alone to easily move between the inside and outside of the reactor containment vessel 1 without using a door.

[0028] In addition to the vent mechanism 22 with a filter, a foreign matter collection mechanism 20 may be installed as needed to collect the foreign matter 21.

[0029] Example 4 4 is a schematic cross-sectional view showing a fourth embodiment of a reactor containment vessel inside inspection work device 28 according to the present invention. In FIG. 4, the same parts as those in FIG. 1 to FIG. 3 are designated by the same reference numerals, and description of the configuration of those parts will be omitted.

[0030] In this fourth embodiment, the reactor containment vessel inside inspection work device 28 shown in Figures 1 to 3 has a structure in which a water purification mechanism 23 equipped with a pump and a strainer is attached to the bottom of a rectangular pipe 9 having a partition plate 10 as shown in Figure 4.

[0031] When the inspection work device 16 inside the reactor containment vessel 1 is in use, the inspection work device 16 moves back and forth between the pipe inlet 11 and the pipe outlet 12, contaminating the liquid stored in the rectangular pipe 9 with the partition plate 10. This can worsen the surrounding environmental conditions, and there is a risk that fine impurities 24 such as rust adhering to the inner wall of the pipe 26, which are the cause of the contamination, may get caught in the driving parts such as gears of the work device 16, rendering it unable to move. Therefore, by installing a water purification mechanism 23, the fine impurities 24 inside the rectangular pipe 9 with the partition plate 10 can be removed, improving the contaminated state.

[0032] In this embodiment, a foreign matter collection mechanism 20 and a vent mechanism 22 can be installed as needed.

[0033] Example 5 Fig. 5 is a schematic cross-sectional view showing a fifth embodiment of a reactor containment vessel inside inspection work device 28 according to the present invention. In Fig. 5, the same parts as those in Figs. 1 to 4 are designated by the same reference numerals, and description of the configuration of those parts will be omitted.

[0034] In this embodiment 5, the reactor containment vessel inside inspection work device 28 shown in Figures 1 to 4 has a structure in which a horizontally sliding base 25 is attached to the bottom of a rectangular pipe 9 having a partition plate 10 as shown in Figure 5.

[0035] When the inspection work device 16 inside the reactor containment vessel 1 is in use, the inspection work device 16 passes through the bottom of the rectangular pipe 9 where the partition plate 10 is located, as it travels between the pipe inlet 11 and the pipe outlet 12. When doing so, the inspection work device 16 must temporarily move through an open space, and there is a risk that the inspection work device 16, which moves by bracing itself against the inner wall of the pipe, will not be able to move on its own. For this reason, by installing a horizontally sliding base 25, the inspection work device 16 can move horizontally after reaching the bottom of the rectangular pipe 9 where the partition plate 10 is located, helping it to pass through the open space.

[0036] The horizontally sliding base 25 may be a carriage or a drive unit that has a drive unit and moves underwater.

[0037] In this embodiment, a foreign matter collection mechanism 20, a vent mechanism 22, and a water purification mechanism 23 can be installed as needed.

[0038] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention.

[0039] These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention.

[0040] These embodiments and their variations are intended to be included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0041] 1... reactor containment vessel, 2... suspended matter, 3... reactor building, 4... primary boundary, 5... secondary boundary, 6... door, 7... door, 8... water seal, 9... rectangular piping, 10... partition plate, 11... piping inlet, 12... piping outlet, 13... joint, 14... penetration hole, 15... input space, 16... inspection work equipment, 17... reactor pressure vessel, 18... water inlet, 19... drain, 20... foreign object recovery mechanism, 21... foreign object, 22... vent mechanism, 23... water purification mechanism, 24... impurities, 25... horizontally sliding base, 26... piping, 27... initial placement space, 28... inspection work equipment inside the reactor containment vessel.

Claims

1. A reactor containment vessel interior inspection work device used for inspection work inside a reactor containment vessel that contains a reactor pressure vessel, An inspection work device inside a reactor containment vessel, characterized in that a reactor building that houses the reactor containment vessel is in communication with the inside of the reactor containment vessel, and piping for introducing an inspection work device is connected to the reactor containment vessel via a water seal.

2. 2. The inspection work device for inside a reactor containment vessel according to claim 1, wherein the water seal device uses a rectangular pipe in which a partition plate is placed at the top, a flow path is formed at the bottom, and liquid is stored with the water surface formed above the lower end of the partition plate.

3. 3. The apparatus for inspecting and working inside a containment vessel according to claim 1, wherein a foreign object recovery mechanism is connected to the water seal on the side of the containment vessel.

4. 3. The inspection device for inspecting inside a containment vessel according to claim 1, wherein a vent mechanism is installed on the side of the water seal on the containment vessel side.

5. 3. The apparatus for inspecting the inside of a nuclear reactor containment vessel according to claim 1, wherein the water seal has a water purification mechanism disposed at its bottom.

6. 3. The apparatus for inspecting the inside of a containment vessel according to claim 1, wherein the water seal comprises a horizontally sliding base disposed at the bottom thereof.

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