Reactor container cooling device

Abstract

To provide a cooling device for a reactor container which can obtain excellent cooling performance from an initial stage of an accident with small power.SOLUTION: A cooling device for a reactor container comprises a wall section that at least partially surrounds the reactor container, a first flow path forming member, and a second flow path forming member. The first flow path forming member forms a first flow path through which a coolant can pass between an upper surface of the reactor container and itself. The second flow path forming member is provided between the wall section and the first flow path forming member and forms a second flow path through which the coolant can pass between the first flow path forming member and itself. The first flow path and the second flow path each have a first opening and a second opening that open to a space surrounded by the wall section, and communicate with each other via a first communication section provided on a lower side relative to the first opening and second opening.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a nuclear containment vessel cooling system. [Background technology]

[0002] When the reactor containment vessel for containing a nuclear reactor becomes hot due to an accident or malfunction, the fluid (e.g., water, etc.) inside expands, causing the internal pressure to rise, and in some cases, damage such as explosion may occur. In order to prevent such damage, cooling equipment is installed in the conventional reactor containment vessel beforehand to cool the reactor containment vessel as necessary, and measures are taken to prevent damage.

[0003] For example, Patent Document 1 discloses a cooling system capable of cooling a fluid used for cooling inside a reactor containment vessel by exchanging heat with a heat exchanger installed outside the reactor containment vessel. Patent Document 2 discloses a system capable of cooling a reactor containment vessel by injecting cooling water into the inside of the reactor containment vessel from a water injection unit installed at the bottom of the reactor containment vessel. Patent Document 3 discloses a system that secures a space for storing cooling water in the upper part of the reactor containment vessel and can cool the upper side of the reactor containment vessel using the cooling water stored in the space. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-77348 A [Patent Document 2] JP 2015-227830 A [Patent Document 3] Japanese Patent Application Publication No. 2-122300 Summary of the Invention [Problem to be solved by the invention]

[0005] The cooling equipment disclosed in the above Patent Documents 1 and 2 operates using power supplied from the outside, and therefore, if the power supply from the outside is stopped, for example, as in the case of a station breakout (SBO), the reactor containment vessel cannot be cooled. In Patent Document 1, the fluid in the reactor containment vessel is conveyed to a heat exchanger outside the reactor containment vessel by a pipe penetrating the reactor containment vessel to remove decay heat, so that radioactive materials contained in the cooling water may leak out depending on the accident scenario. In Patent Document 2, water is injected into the lower part of the reactor containment vessel from the side, so that the cooling water injected by static operation may not be distributed appropriately throughout the entire target section in the reactor containment vessel.

[0006] On the other hand, in Patent Document 3, a space for storing cooling water is secured in the upper part of the reactor containment vessel, and the cooling water stored in the space is used to cool the upper part of the reactor containment vessel, so that it is possible to secure a certain degree of cooling performance even when cooling equipment that requires external power is inoperable. However, in an event such as an SBO, it is assumed that the amount of this cooling water to be used may be limited. Therefore, performance is required to efficiently cool the reactor containment vessel with limited cooling water.

[0007] In addition, in Patent Document 3, in order to obtain sufficient cooling performance, it is necessary to store a sufficient amount of cooling water in the upper part of the reactor containment vessel. Therefore, in the early stage of the accident, the amount of cooling water stored in the upper part of the reactor containment vessel is small, and sufficient cooling performance cannot be obtained. In other words, in order to obtain sufficient cooling performance, it is necessary to wait until a sufficient amount of cooling water is stored in the upper part of the reactor containment vessel, and there is a risk that the cooling performance in the early stage of the accident may be insufficient.

[0008] At least one embodiment of the present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a reactor containment vessel cooling device that can obtain good cooling performance from the early stage of an accident with little power. [Means for solving the problem]

[0009] In order to solve the above problems, the reactor containment vessel cooling device according to at least one embodiment of the present disclosure includes: a wall portion at least partially surrounding an upper portion of the reactor containment vessel; a first flow path forming member extending along an upper surface provided on the upper portion and forming a first flow path between the upper surface and the first flow path forming member and the upper surface, through which a coolant can pass; a second flow path forming member provided between the wall portion and the first flow path forming member, forming a second flow path through which the coolant can pass between the second flow path forming member and the first flow path forming member; Equipped with The first flow path and the second flow path have a first opening and a second opening, respectively, that open into a space surrounded by the wall portion, and are connected to each other via a first communication portion provided below the first opening and the second opening. Effect of the Invention

[0010] According to at least one embodiment of the present disclosure, it is possible to provide a reactor containment vessel cooling device that can obtain good cooling performance from the early stage of an accident occurrence with little power. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of a nuclear power plant according to an embodiment; [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a cooling device provided in the reactor containment vessel of FIG. [Diagram 3] 3 is an enlarged view showing a schematic view of cooling water overflowing in range A in FIG. 2. [Figure 4] 5 is a simplified cross-sectional view corresponding to FIG. 3 of a cooling device according to another embodiment. FIG. [Diagram 5] 5 is a simplified cross-sectional view showing a state in which the check valve in FIG. 4 operates. FIG. [Figure 6] 3 is a perspective view showing the vicinity of the first flow path and the second flow path of FIG. 2 in a cooling device according to another embodiment. FIG. [Figure 7] This is a modified example of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, some embodiments will be described with reference to the accompanying drawings. However, the configurations described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention.

[0013] First, an overall configuration of a nuclear power plant including a containment vessel cooling device according to at least one embodiment of the present disclosure will be described. Fig. 1 is a schematic configuration diagram of a nuclear power plant 1 according to one embodiment.

[0014] The nuclear power plant 1 includes a nuclear reactor 2 for generating steam from thermal energy generated by a nuclear fission reaction. The nuclear reactor 2 shown in Fig. 1 is a pressurized water reactor (PWR). In other embodiments, the nuclear reactor 2 may be a boiling water reactor (BWR), or may be a type of nuclear reactor that uses a substance other than light water as a moderator or coolant, unlike light water reactors including pressurized water reactors and boiling water reactors.

[0015] The reactor 2 includes a primary cooling loop 10 through which primary cooling water (primary coolant) flows, and a reactor vessel (pressure vessel) 11, a pressurizer 14, a steam generator 16, and a primary coolant pump 18 provided in the primary cooling loop 10. The primary coolant pump 18 is configured to circulate the primary cooling water in the primary cooling loop 10. The pressurizer 14 is configured to pressurize the primary cooling water in the primary cooling loop 10 so that the primary cooling water does not boil. The reactor pressure vessel 11, the pressurizer 14, the steam generator 16, and the primary coolant pump 18 constituting the reactor 2 are contained in a reactor containment vessel 19.

[0016] The reactor pressure vessel 11 contains fuel rods including pellet-shaped nuclear fuel (e.g., uranium fuel, MOX fuel, etc.), and the primary coolant in the reactor pressure vessel 11 is heated by thermal energy generated by the nuclear fission reaction of this fuel. The reactor pressure vessel 11 is provided with control rods 13 for absorbing and adjusting the number of neutrons generated in the core including the nuclear fuel in order to control the reactor output. The primary coolant heated in the reactor pressure vessel 11 is sent to a steam generator 16, where it heats the secondary coolant (secondary coolant) flowing in a secondary cooling loop (not shown) by heat exchange to generate steam.

[0017] The steam generated in the steam generator 16 is sent to a steam turbine (not shown) to rotate the steam turbine. The steam turbine is also connected to a generator via a rotating shaft, and the generator is driven by the rotation of the rotating shaft to generate electrical energy. After performing work, the steam returns to the steam generator 16 via a secondary cooling loop. Although FIG. 1 illustrates a conventional PWR as the nuclear reactor 2, the nuclear reactor 2 may be a small reactor.

[0018] Next, a description will be given of a containment vessel cooling system (hereinafter, referred to as "cooling system") provided in the containment vessel 19. Fig. 2 is a schematic diagram showing the configuration of a cooling system 30 provided in the containment vessel 19 of Fig. 1, and Fig. 3 is an enlarged view showing a schematic view of the cooling water overflowing in range A of Fig. 2.

[0019] In addition, in Figure 2 and subsequent figures, the internal configuration of the reactor containment vessel 19 described above with reference to Figure 1 is shown collectively and simplified as an internal reactor structure 32 (for example, the internal reactor structure includes the reactor pressure vessel 11, control rods 13, pressurizer 14, steam generator 16, primary coolant pump 18, etc., contained in the current containment vessel 19 shown in Figure 1).

[0020] The reactor containment vessel 19 has a closed structure that houses the reactor internals 32 therein. The reactor containment vessel 19 includes a substantially cylindrical main body 34 that surrounds the reactor internals 32 from the sides, and an upper surface 36 and a lower surface (not shown) that are combined with the top and bottom of the main body 34. The main body 34, the upper surface 36, and the lower surface (not shown) may each be configured as separate bodies and combined with each other to configure the reactor containment vessel 19, or at least a portion of these may be configured as an integral body.

[0021] 2 focuses on a relatively upper side including the upper surface 36 of the containment vessel 19. The upper surface 36 has a schematic configuration that is convex upward, and more specifically, has a convex portion 36a that protrudes upward near the axial center of the main body portion 34, and an upper side surface 36b provided between the convex portion 36a and the main body portion 34. The upper side surface 36b is configured as a curved surface having a predetermined curvature. The convex portion 36a protrudes upward from the upper side surface 36b via a step 36c, and the upper portion of the convex portion 36a is also configured as a curved surface. It should be noted that such a shape of the upper surface 36 is merely an example and is not limited to this.

[0022] The cooling device 30 includes a wall portion 44, a first flow path forming member 46, and a second flow path forming member 48. The wall portion 44 is part of the building that houses the reactor containment vessel 19, and at least partially covers an upper portion of the reactor containment vessel 19. In this embodiment, the wall portion 44 surrounds the entire reactor containment vessel 19 (FIG. 2 representatively shows a portion of the wall portion 44 near the upper surface 36).

[0023] The first flow path forming member 46 and the second flow path forming member 48 form a flow path for cooling water supplied by a water injection mechanism (not shown), and can cool the upper surface 36 of the reactor containment vessel 19 by storing the cooling water in a structure formed by them. The reactor containment vessel 19 is made of a metal material such as stainless steel, and the upper surface 36 of the reactor containment vessel 19 is cooled by heat exchange with the stored cooling water.

[0024] The cooling device 30 may include a water injection mechanism (not shown) for injecting water into the inside of the reactor containment vessel 19. In this case, the cooling water injected into the inside of the reactor containment vessel 19 by the water injection mechanism is converted into steam by heat exchange with the high-temperature reactor internals 32, and fills the inside of the reactor containment vessel 19. Since the reactor containment vessel 19 is made of a metal material, the steam filling the inside of the reactor containment vessel 19 is cooled by heat exchange with the cooling water stored in a structure including the first flow path forming member 46 and the second flow path forming member 48. The cooled steam may be partially condensed and returned to the cooling water. The steam or cooling water cooled in this way is used again to cool the reactor internals 32, thereby suppressing the temperature rise of the reactor internals 32.

[0025] The first flow passage forming member 46 extends along the upper surface 36 provided at the top of the reactor containment vessel 19. A first flow passage 50 through which the coolant can pass is formed between the upper surface 36 and the first flow passage forming member 46. Since the upper surface 36 of the reactor containment vessel 19 is configured as a curved surface as described above, the first flow passage restricting member 46 is also configured as a curved surface with a majority thereof conforming to the upper surface 36. In this embodiment, since the upper surface 36 of the reactor containment vessel 19 has a step portion 36c between the convex portion 36a and the upper side surface 36b, the upper end portion 46a of the first flow passage forming member 46 is also partially configured to correspond to the step portion 36c.

[0026] The second flow path forming member 48 is provided between the wall portion 44 and the first flow path forming member 46, and extends along the first flow path forming member 46. A second flow path 52 through which the coolant can pass is formed between the first flow path forming member 46 and the second flow path forming member 48. Since the first flow path forming member 46 is mostly configured as a curved surface as described above, the second flow path restricting member 48 is also mostly configured as a curved surface that follows the first flow path forming member 46. In this embodiment, an upper end portion 48a of the second flow path forming member 48 is partially configured to correspond to an upper end portion 46a of the first flow path forming member 46. The first flow path forming member 46 may be provided with at least one hole formed so as to penetrate the first flow path forming member 46. This allows the first flow path 50 and the second flow path 52 to communicate with each other via the hole, thereby promoting a circulating flow from the second flow path 52 to the first flow path 50. In this case, the number and shape of the holes provided in the first flow path forming member 46 may be arbitrary.

[0027] The first flow path 50 and the second flow path 52 formed by the first flow path forming member 46 and the second flow path forming member 48 have a first opening 54 and a second opening 56, respectively, on their upper sides. The first opening 54 and the second opening 56 open into a space V inside the building that is surrounded by the wall portion 44. On the other hand, the lower sides of the first flow path 50 and the second flow path 52 communicate with each other via a first communication portion 58.

[0028] The cooling device 30 is capable of supplying cooling water to the second opening 56. As shown by the arrow in Fig. 2, the cooling water is supplied to the second opening 56 from above. The cooling water supplied to the second opening 56 flows downward along the second flow path 52 connected to the second opening 56, and reaches the first communication part 58. The cooling water is then introduced from the first communication part 58 into the first flow path 50, and flows toward the first opening 54 located above.

[0029] As described above, the first flow passage forming member 46 and the second flow passage forming member 48 are formed so as to be aligned with the upper surface 36 of the containment vessel 19, and therefore the first flow passage 50 and the second flow passage 52 are configured to have a relatively small volume. In particular, the upper surface 36, the first flow passage forming member 46, and the second flow passage forming member 48 are designed to have curvatures close to each other, so that the volumes of the first flow passage 50 and the second flow passage 52 become relatively small. As a result, when cooling water is supplied to the second opening 56, the first flow passage 50 and the second flow passage 52 can be filled with the cooling water in a relatively short time. As a result, at an early stage after the start of the supply of cooling water to the second opening 56, the cooling water filled in the first flow passage 50 and the second flow passage 52 can be heat exchanged with the upper surface 36 of the containment vessel 19 to start cooling.

[0030] The cooling water stored in the first flow passage 50 and the second flow passage 52 forms a convection current as indicated by the arrow B due to the inertial force when it is supplied to the second opening 56 so as to fall from above, and the temperature difference caused by heat exchange with the upper surface 36. This promotes heat exchange between the cooling water stored in the first flow passage 50 and the second flow passage 52 and the upper surface 36, and provides a good cooling effect.

[0031] The surfaces of the cooling water in the first flow passage 50 and the second flow passage 52 are approximately equal, but as the supply rate of the cooling water increases, the surfaces gradually rise. When the supply rate of the cooling water becomes sufficiently large, the surfaces of the cooling water in the first flow passage 50 and the second flow passage 52 reach the first opening 54 and the second opening 56. Then, when the supply rate of the cooling water further increases, the cooling water eventually overflows from the first opening 54 and the second opening 56 to the surroundings, as shown by arrow C in FIG. 3.

[0032] Here, a reservoir 60 is formed between the second flow path forming member 48 and the wall surface 44. Therefore, the cooling water overflowing from the first flow path 50 and the second flow path 52 is stored in the reservoir 60. Since the first flow path forming member 46 and the second flow path forming member 48 are also made of a metal material, the cooling water stored in the reservoir 60 indirectly contributes to cooling the reactor containment vessel 19.

[0033] The upper ends 46a and 48a of the first flow path forming member 46 and the second flow path forming member 48 are designed so that the cooling water overflowing from the first flow path 50 and the second flow path 52 is introduced into the storage section 60. In this embodiment, the upper ends 46a and 48a of the first flow path forming member 46 and the second flow path forming member 48 are set to be at substantially the same height, but they may be set to be different from each other. For example, since the second flow path forming member 48 is closer to the storage section 60 than the first flow path forming member 46, the upper end 48a of the second flow path forming member 48 may be set lower than the upper end 46a of the first flow path forming member 46, so that the cooling water overflowing from the first flow path 50 and the second flow path 52 is easily introduced into the storage section 60.

[0034] FIG. 4 is a simplified cross-sectional view corresponding to FIG. 3 of a cooling device 30 according to another embodiment (main components are shown in a simplified manner in FIG. 4, and components corresponding to those described above are given common reference numerals). In this embodiment, the cooling device 30 is different from the above-described embodiment in that a check valve 64 is provided in a second communication portion 62 that communicates the storage portion 60 with the second flow path 52. The second communication portion 62 is formed by providing an opening in a part of the second flow path forming member 48 that defines the second flow path 52 so as to communicate the storage portion 60 with the second flow path 52. In this embodiment, in particular, the second communication portion 62 is provided at a position facing the first communication portion 58 (in other words, at a height position substantially equal to that of the first communication portion 58).

[0035] The check valve 64 is configured to allow a one-way flow of cooling water from the storage section 60 to the second flow path 52 based on a pressure difference between the second flow path 52 and the storage section 60. Specifically, when the pressure of the cooling water stored in the storage section 60 becomes sufficiently higher than the pressure of the cooling water in the second flow path 52, the cooling water stored in the storage section 60 is supplied to the second flow path 52 via the check valve 64.

[0036] For example, in Fig. 4, the difference between the water surface position in the second flow path 52 and the water surface position in the storage section 60 is relatively small. Therefore, the pressure difference between the second flow path 52 and the storage section 60 is small, and the check valve 64 does not operate (in this case, the cooling water stored in the storage section 60 is stopped). On the other hand, as shown in Fig. 5, for example, when the cooling water in the first flow path 50 or the second flow path 52 evaporates due to heat exchange with the upper surface 36, and the water surface position in the second flow path 52 drops, the pressure difference between the second flow path 52 and the storage section 60 becomes large. Then, the check valve 64 operates, and the cooling water stored in the storage section 60 is introduced into the second flow path 52 through the second communication section 62 (see arrow C in Fig. 5). As a result, the cooling water introduced from the storage section 60 to the second flow path 52 circulates from the second flow path 52 to the first flow path 50 together with the cooling water supplied from the second opening 56, thereby improving the heat exchange efficiency with the upper surface 36 of the reactor containment vessel 19 and achieving better cooling performance.

[0037] 6 is a perspective view showing the vicinity of the first flow passage 50 and the second flow passage 52 of FIG. 2 of the cooling device 30 according to another embodiment. In this embodiment, at least one of the first flow passage 50 or the second flow passage 52 is provided with a rib 70 that at least partially divides the first flow passage 50 or the second flow passage 52 and extends in the up-down direction (i.e., the direction along each flow passage). In the embodiment illustrated in FIG. 6, the rib 70 provided in the second flow passage 52 is representatively shown, but a similar rib 70 may also be provided in the first flow passage 50 (the rib 70 may be provided in at least one of the first flow passage 50 or the second flow passage 52).

[0038] The rib 70 is erected on at least one of the surfaces defining the first flow path 50 or the second flow path 52. The rib 70 provided on the second flow path 52 illustrated in this embodiment extends from the surface of the first flow path forming member 46 to the surface of the second flow path forming member 48, thereby dividing the second flow path 52 into a plurality of spaces. By providing the rib 70 on the second flow path 52 in this manner, the cooling water in the second flow path 52 is rectified. This suppresses the unstable flow of the cooling water in the second flow path 52, and good cooling performance is obtained. In addition, the rib 70 is erected between the first flow path forming member 46 and the second flow path forming member 48, thereby reinforcing these members and contributing to improving the mechanical strength.

[0039] Fig. 7 is a modified example of Fig. 4. In this modified example, a slit portion 80 is provided in the first communication portion 58 that communicates between the first flow path 50 and the second flow path 52. The slit portion 80 is configured to locally narrow the flow path area, and extends along the depth direction (approximately horizontal direction) in Fig. 7. By having such a slit portion 80, the cooling water passing through the first communication portion 58 is rectified, and unstable flow of the cooling water is suppressed. The slit portion 80 can be used in combination with the rib 70 shown in Fig. 6 to obtain this effect more effectively.

[0040] Although FIG. 7 illustrates an example in which the slit portion 80 is provided on the first flow path 50 side of the first communication portion 58, it may be provided on the second flow path 52 side.

[0041] As described above, according to each of the above embodiments, the first flow passage forming member 46 and the second flow passage forming member 48 arranged on the upper surface 36 of the reactor containment vessel 19 form the first flow passage 50 and the second flow passage 52 through which the cooling water can pass. The first opening 54 and the second opening 56 are provided at the upper ends 46a and 48a of the first flow passage 50 and the second flow passage 52, respectively, and the other ends are communicated with each other via the first communication part 58. As a result, the cooling water flowing through the first flow passage 50 in contact with the upper surface 36 of the reactor containment vessel 19 moves upward through the first flow passage 50 by being heated by the amount of heat received from the upper surface 36 of the reactor containment vessel 19, and new coolant is introduced from the second flow passage 52 into the first flow passage 50 via the first communication part 58. As a result, the upper surface 36 of the reactor containment vessel 19 is suitably cooled by heat exchange with the cooling water flowing through the first flow passage 50. As a result, it is possible to provide a cooling device 30 for a reactor containment vessel 19 that can obtain good cooling performance from the early stage of an accident occurrence with little power.

[0042] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0043] The contents described in each of the above embodiments can be understood, for example, as follows.

[0044] (1) A reactor containment vessel cooling apparatus according to one aspect comprises: a wall portion at least partially surrounding an upper portion of the reactor containment vessel; a first flow path forming member extending along an upper surface provided on the upper portion and forming a first flow path between the upper surface and the first flow path forming member and the upper surface, through which a coolant can pass; a second flow path forming member provided between the wall portion and the first flow path forming member, forming a second flow path through which the coolant can pass between the second flow path forming member and the first flow path forming member; Equipped with The first flow path and the second flow path have a first opening and a second opening, respectively, that open into a space surrounded by the wall portion, and are connected to each other via a first communication portion provided below the first opening and the second opening.

[0045] According to the above aspect (1), a first flow passage and a second flow passage through which the coolant can pass are formed by a first flow passage forming member and a second flow passage forming member arranged on the upper surface of the reactor containment vessel. An opening is provided at one end of each of the first flow passage and the second flow passage, and the other ends are communicated with each other via a first communication part. As a result, the coolant flowing through the first flow passage in contact with the upper surface of the reactor containment vessel moves upward in the first flow passage by being heated by the amount of heat received from the upper surface of the reactor containment vessel, and new coolant is introduced from the second flow passage into the first flow passage via the first communication part. As a result, the upper surface of the reactor containment vessel is suitably cooled by heat exchange with the coolant flowing through the first flow passage.

[0046] (2) In another embodiment, in the above embodiment (1), The coolant is supplyable to the second opening.

[0047] According to the above aspect (2), the coolant supplied to the second opening is introduced from the second flow passage into the first flow passage via the first communication part, thereby promoting heat exchange with the upper surface of the reactor containment vessel by supplying new coolant from the second flow passage side to the first flow passage in contact with the upper surface of the reactor containment vessel, and obtaining a good cooling effect.

[0048] (3) In another embodiment, in the above embodiment (1) or (2), The second flow path forming member extends along the first flow path forming member.

[0049] According to the above aspect (3), the second flow passage forming member is configured to extend along the first flow passage forming member along the upper surface of the reactor containment vessel. This makes the volumes of the first flow passage and the second flow passage relatively small, so that the filling of the coolant can be completed quickly from the start of the supply of the coolant. In other words, when the supply of the coolant is started at the time of the occurrence of an accident, the filling of the coolant into the first flow passage and the second flow passage can be completed quickly, so that the cooling effect can be obtained early.

[0050] (4) In another embodiment, in any one of the above (1) to (3), A reservoir capable of storing the coolant overflowing from the first flow path or the second flow path is formed between the second flow path forming member and the wall portion.

[0051] According to the above aspect (4), the coolant overflowing from the first flow path and the second flow path is stored in a storage section provided between the second flow path forming member and the wall section. By providing such a storage section, the volume of the coolant used to cool the containment vessel is increased, and therefore, by increasing the cooling capacity of the present device, the containment vessel can be more suitably cooled.

[0052] (5) In another embodiment, in the above embodiment (4), The first flow path forming member has an upper end higher than the second flow path forming member.

[0053] According to the above aspect (5), the upper end of the first flow path forming member is provided at a position higher than the upper end of the second flow path forming member, whereby the coolant overflowing from the first flow path and the second flow path can be suitably guided to the storage section.

[0054] (6) In another embodiment, in the above embodiment (4) or (5), A second communication portion that communicates the storage portion and the second flow path; a check valve provided in the second communication portion and configured to allow the coolant to flow from the storage portion to the second flow path; Equipped with.

[0055] According to the above aspect (6), the second communication part that communicates the storage part with the second flow path is provided with a check valve that allows the coolant to flow from the storage part to the second flow path. As a result, when the pressure on the storage part side becomes greater than the pressure on the second flow path side, the coolant stored in the storage part is introduced into the second flow path due to the pressure difference between the two. As a result, the coolant stored in the storage part circulates from the second flow path to the first flow path side, improving the heat exchange efficiency with the upper surface of the reactor containment vessel and obtaining better cooling performance.

[0056] (7) In another embodiment, in the above embodiment (6), The second communication portion is provided to face the first communication portion.

[0057] According to the above aspect (7), the second communication part is provided to face the first communication part. As a result, the coolant introduced from the reservoir to the second flow path through the second communication part is smoothly guided to the first flow path through the first communication part. This improves the heat exchange efficiency with the upper surface of the reactor containment vessel, and provides better cooling performance.

[0058] (8) In another embodiment, in any one of the above (1) to (7), The first flow passage is at least partially partitioned, and a first rib is provided extending along the vertical direction.

[0059] According to the above aspect (8), the first rib is provided in the first flow passage, thereby rectifying the flow of the coolant in the first flow passage, thereby suppressing unstable flow of the coolant in the first flow passage and promoting heat exchange between the coolant flowing in the first flow passage and the upper surface of the reactor containment vessel, thereby obtaining good cooling performance.

[0060] (9) In another embodiment, in the above embodiment (8), The first rib is erected on the upper surface.

[0061] According to the above aspect (9), the first rib is erected on the upper surface of the reactor containment vessel, whereby the upper surface can be reinforced by the first rib, and the mechanical strength of the present device can be effectively improved.

[0062] (10) In another embodiment, in any one of the above (1) to (9), The second flow passage is at least partially partitioned, and a second rib is provided extending along the up-down direction.

[0063] According to the above aspect (10), the second flow passage is provided with the second rib, thereby rectifying the flow of the coolant in the second flow passage, thereby suppressing unstable flow of the coolant in the second flow passage and efficiently guiding the coolant from the second flow passage to the first flow passage via the first communication part, thereby obtaining good cooling performance. [Explanation of symbols]

[0064] 1. Nuclear power plants 2 nuclear reactor 10 Primary Cooling Loop 11 Reactor vessel (pressure vessel) 14 Pressurizer 16 Steam Generator 18 Primary Coolant Pump 19 Reactor Containment Vessel 20 Secondary Cooling Loop 30. Nuclear Reactor Containment Vessel Cooling System 32 Reactor internals 34 Main body 36 Top 36a Convex part 36b Top side 44 Wall 46 First flow path forming member 46a top end 48 Second flow path forming member 48a top end 50 First Channel 52 Second Flow Path 54 First Opening 56 Second Opening 58 1st communication part 60 Storage section 62 2nd communication passage 64 Check valve 70 Ribs 80 Slit section

Claims

1. a wall portion at least partially surrounding an upper portion of the reactor containment vessel; a first flow passage forming member extending along an upper surface provided on the upper portion and forming a first flow passage through which a coolant can pass between the first flow passage forming member and the upper surface; a second flow path forming member provided between the wall portion and the first flow path forming member, forming a second flow path through which the coolant can pass between the first flow path forming member and the second flow path forming member; Equipped with the first flow path and the second flow path have a first opening and a second opening, respectively, that open into a space surrounded by the wall portion, and communicate with each other via a first communication portion provided below the first opening and the second opening.

2. The containment vessel cooling system of claim 1 , wherein the coolant is supplyable to the second opening.

3. 3. The containment vessel cooling device according to claim 1, wherein the second flow passage forming member extends along the first flow passage forming member.

4. 3. The reactor containment vessel cooling device according to claim 1, wherein a storage portion capable of storing the coolant overflowing from the first flow path or the second flow path is formed between the second flow path forming member and the wall portion.

5. 5. The reactor containment vessel cooling device according to claim 4, wherein an upper end of the first flow passage forming member is provided higher than an upper end of the second flow passage forming member.

6. A second communication portion that communicates the storage portion and the second flow path; a check valve provided in the second communication portion and configured to allow the coolant to flow from the storage portion to the second flow path; The containment vessel cooling system of claim 4 .

7. 7. The containment vessel cooling device according to claim 6, wherein the second communication portion is provided opposite to the first communication portion.

8. 3. The containment vessel cooling device according to claim 1, further comprising a first rib that at least partially divides the first flow passage and extends along the up-down direction.

9. 9. The containment vessel cooling device according to claim 8, wherein the first rib is provided upright on the upper surface.

10. 3. The containment vessel cooling device according to claim 1, further comprising a second rib that at least partially divides the second flow passage and extends along the up-down direction.

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