Water injection cooling system and method

Abstract

The invention provides a water injection cooling system and method.The water injection cooling system comprises a pressure vessel lower end socket, a pressure vessel lower end socket outer heat preservation layer is arranged on the outer side of the pressure vessel lower end socket, and a cooling medium runner is formed between the pressure vessel lower end socket and the pressure vessel lower end socket outer heat preservation layer; a heat preservation layer runner water injection pipe inlet protruding outwards is formed in the outer heat preservation layer of the lower sealing head of the pressure vessel, and a passive water injection baffle is arranged between a water injection outlet of the water injection pipeline and the heat preservation layer runner water injection pipe inlet and hinged to the water injection outlet; and the cooling medium in the large space of the containment generates buoyancy to push the passive water injection baffle to be opened, so that the cooling medium enters the cooling medium runner to carry out passive circulating cooling on the lower sealing head of the pressure vessel. Passive natural circulation of a cooling medium in a large space of the containment vessel is realized, and meanwhile, a lower sealing head of the pressure vessel can be submerged in a short time.

Description

Technical Field

[0001] The present application belongs to the technical field of nuclear reactor safety design, and specifically relates to a water injection cooling system and method. Background Art

[0002] In the related technology, a fully passive water injection cooling method is generally used for water injection cooling of the containment / combustion cavity. The AP1000 nuclear power plant is a representative example. Due to its relatively low position in the reactor cavity, when the cooling water enters the containment / combustion cavity for water injection, the cold water can quickly flood the small space of the reactor cavity; however, for the large space of the containment compartment of the "Hualong Follow-up" power plant, the volume of cooling water required for flooding is at least twice that of the AP1000 nuclear power plant. If the large space of the containment compartment is completely flooded by gravity water injection in a short period of time, the required water injection flow rate is large, so a larger diameter water injection pipe is required. However, since the water injection pipe needs to pass through the containment, in the event of an accident, the radioactive material in the primary circuit will be released into the containment. Therefore, if the diameter of the water injection pipe is too large, the risk of leakage of the containment bypass will be greatly increased, thereby increasing the risk of radioactive material being released into the environment. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present application is to provide a water injection cooling system and method to solve at least one of the above problems existing in the prior art.

[0004] In order to solve the above problems, the first aspect of the present application provides a water injection cooling system, including a lower head of a pressure vessel, a water injection pipeline and a large containment space;

[0005] An outer insulation layer of the lower head of the pressure vessel is arranged on the outside of the lower head of the pressure vessel, and a cooling medium flow channel is formed between the lower head of the pressure vessel and the outer insulation layer of the lower head of the pressure vessel; an insulation layer flow channel water injection pipe inlet protruding outward is arranged on the outer insulation layer of the lower head of the pressure vessel; the water injection pipeline includes a water injection outlet, and the water injection outlet is arranged opposite to the insulation layer flow channel water injection pipe inlet, and a non-active water injection baffle is arranged between the water injection outlet and the insulation layer flow channel water injection pipe inlet, and the non-active water injection baffle is hinged to the water injection outlet; the cooling medium in the large space of the containment generates buoyancy to push the non-active water injection baffle to open, so that the cooling medium enters the cooling medium flow channel to perform non-active circulation cooling on the lower head of the pressure vessel.

[0006] Optionally, when the passive water injection baffle is not pushed by the buoyancy of the cooling medium in the large space of the containment shell, the passive water injection baffle cover is arranged on the inlet of the insulation layer flow channel water injection pipe to close the inlet of the insulation layer flow channel water injection pipe; when the passive water injection baffle is pushed by the buoyancy of the cooling medium in the large space of the containment shell, the non-passive water injection baffle is separated from the inlet of the insulation layer flow channel water injection pipe to open the inlet of the insulation layer flow channel water injection pipe.

[0007] Optionally, the diameter of the inlet of the insulation layer flow channel water injection pipe is larger than the diameter of the water injection pipeline.

[0008] Optionally, there are at least three passive water injection baffles, each of which includes a short side and a wide side. The short side of the passive water injection baffle faces the water injection pipeline and is hingedly connected to the water injection pipeline, and the wide side of the passive water injection baffle faces the inlet of the insulation layer flow channel water injection pipe, and is used to close or open the inlet of the insulation layer flow channel water injection pipe.

[0009] Optionally, an insulation layer flow channel water injection outlet is provided on the outer insulation layer of the lower head of the pressure vessel, and when the height of the cooling medium in the cooling medium flow channel exceeds the height of the insulation layer flow channel water injection outlet, the cooling medium flows into the large space of the containment shell through the insulation layer flow channel water injection outlet.

[0010] Optionally, the water injection cooling system also includes an elevated water tank outside the containment and a connecting pipe, one end of the connecting pipe is connected to the top of the elevated water tank outside the containment, and the other end of the connecting pipe passes through the concrete wall of the containment and extends into the large space of the containment, and the water injection pipeline also includes a water injection inlet, and the water injection inlet of the water injection pipeline passes through the concrete wall of the containment and is connected to the bottom of the elevated water tank outside the containment.

[0011] Optionally, the water injection cooling system further includes a valve, and the water injection pipeline is provided with a valve on the outer side of the containment concrete wall.

[0012] A second aspect of the present application provides a water injection cooling method, using any of the water injection cooling systems described above, comprising the following steps:

[0013] When a high-level water tank outside the containment is included, the cooling medium in the high-level water tank outside the containment is injected into the cooling medium flow channel through the water injection pipeline and the water injection pipe inlet of the insulation layer flow channel, and then the cooling medium flows out through the water injection outlet of the insulation layer flow channel into the large space of the containment;

[0014] When the high-level water tank outside the containment is emptied, the passive water injection baffle is in an open state under the buoyancy of the cooling medium, and the cooling medium in the large space of the containment enters the cooling medium flow channel through the water injection pipe inlet of the insulation layer flow channel to perform passive natural circulation cooling on the lower head of the pressure vessel.

[0015] Optionally, before the high-level water tank outside the containment vessel is emptied, as the water level in the large space of the containment vessel continues to rise, the passive water injection damper is opened or closed.

[0016] Optionally, when the passive water injection damper is closed, only the high-level water tank outside the containment vessel injects the cooling medium into the cooling medium flow channel;

[0017] When the passive water injection baffle is opened under the buoyancy of the cooling medium in the large containment space, the high-level water tank outside the containment and the large containment space simultaneously inject the cooling medium into the cooling medium flow channel.

[0018] Beneficial Effects

[0019] A water injection cooling system and method is provided in an embodiment of the present invention. In the early stage, a water injection pipeline is used to inject the cooling medium in the high-level water tank outside the containment into the cooling medium flow channel by gravity, and the lower head of the pressure vessel is cooled in a one-pass cooling manner to take away the heat of the lower head of the pressure vessel. At the same time, the cooling medium flows out from the water injection outlet of the insulation layer flow channel and gathers in the large space of the containment. As the water level rises, the passive water injection baffle arranged on the upper part of the water injection pipeline opens. At this time, the cooling medium in the large space of the containment and the cooling medium in the high-level water tank outside the containment are simultaneously injected into the cooling medium flow channel, so that the purpose of flooding the lower head of the pressure vessel for a short time under the condition of a large-space containment is achieved; in the later stage, after the water in the high-level water tank outside the containment is emptied, the cooling medium in the large space of the containment continues to cool the lower head of the pressure vessel through natural circulation, which solves the technical problem that the diameter of the water injection pipeline required for flooding the large space of the containment in a short time is too large, which will greatly increase the leakage risk of the containment bypass, thereby increasing the risk of radioactive substances being released into the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a water injection cooling system in which a passive reactor cavity water injection inlet baffle is closed according to an embodiment of the present application;

[0021] Figure 2 Schematic diagram of the water injection cooling system when the passive reactor cavity water injection inlet baffle is open according to an embodiment of the present application.

[0022] The reference numerals are:

[0023] 1-lower head of pressure vessel; 2-outer insulation layer of lower head of pressure vessel; 3-passive water injection baffle; 4-containment concrete wall; 5-high-level water tank outside containment; 6-isolation valve; 7-water injection pipeline; 8-insulation layer flow channel water injection pipe inlet; 9-cooling medium flow channel; 10-insulation layer flow channel water injection outlet; 11-large containment space; 12-connecting pipe. DETAILED DESCRIPTION

[0024] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0028] See also Figure 1 and Figure 2 As shown, according to a first aspect of an embodiment of the present application, a water injection cooling system is provided, comprising:

[0029] A pressure vessel lower head 1, a pressure vessel lower head outer insulation layer 2 is arranged on the outer side of the pressure vessel lower head 1, and a cooling medium flow channel 9 is formed between the pressure vessel lower head 1 and the pressure vessel lower head outer insulation layer 2;

[0030] The outer insulation layer 2 of the lower head of the pressure vessel is provided with an insulation layer flow channel water injection pipe inlet 8 protruding outward;

[0031] A water injection pipeline 7, the water injection pipeline 7 comprises a water injection outlet, the water injection outlet is arranged opposite to the water injection pipe inlet 8 of the thermal insulation layer flow channel, a passive water injection baffle 3 is arranged between the water injection outlet and the water injection pipe inlet 8 of the thermal insulation layer flow channel, and the passive water injection baffle 3 is hinged to the water injection outlet;

[0032] The cooling medium in the large containment space 11 generates buoyancy to push the passive water injection baffle 3 to open, so that the cooling medium enters the cooling medium flow channel 9 to perform passive circulation cooling on the lower head 1 of the pressure vessel.

[0033] In the early stage, the cooling medium in the high-level water tank 5 outside the containment is injected into the cooling medium flow channel 9 by gravity using the water injection pipeline 7, and the lower head 1 of the pressure vessel is cooled in a one-pass cooling manner to take away the heat of the lower head 1 of the pressure vessel. At the same time, the cooling medium flows out from the water injection outlet 10 of the insulation layer flow channel and gathers in the large space 11 of the containment. As the water level rises, the passive water injection baffle 3 arranged on the upper part of the water injection pipeline 7 opens. At this time, the cooling medium in the large space 11 of the containment and the cooling medium in the high-level water tank 5 outside the containment are simultaneously injected into the cooling medium flow channel 9, so that the purpose of flooding the lower head 1 of the pressure vessel for a short time under the condition of a large-space containment is achieved; in the later stage, after the water in the high-level water tank 5 outside the containment is emptied, the cooling medium in the large space 11 of the containment continues to cool the lower head 1 of the pressure vessel through natural circulation, which solves the technical problem that the diameter of the water injection pipeline 7 required for flooding the large space 11 of the containment in a short time is too large, which will greatly increase the leakage risk of the containment bypass, thereby increasing the risk of radioactive substances being released into the environment. At the same time, the integrity of the lower head 1 of the pressure vessel is ensured to prevent it from rupturing, thereby preventing the release of radioactive substances into the large containment space 11, thereby reducing the risk of radioactive substances being released into the environment.

[0034] The water injection cooling system further comprises a containment concrete wall 4 , the space enclosed by the containment concrete wall 4 is a large containment space 11 , and the outer insulation layer 2 of the pressure vessel lower head and the pressure vessel lower head 1 are located in the large containment space 11 .

[0035] Among them, a pressure vessel lower head outer insulation layer 2 is arranged on the outside of the pressure vessel lower head 1, and a cooling medium flow channel 9 is formed between the pressure vessel lower head 1 and the pressure vessel lower head outer insulation layer 2; the cooling medium flow channel 9 is used to realize the circulation of the cooling medium to cool the cold zone of the pressure vessel lower head 1.

[0036] Among them, an outwardly protruding insulation layer flow channel water injection pipe inlet 8 is provided on the outer insulation layer 2 of the lower head of the pressure vessel. The insulation layer flow channel water injection pipe inlet 8 is located at the bottom of the outer insulation layer 2 of the lower head of the pressure vessel and is located at the center position to ensure that the cooling medium can be smoothly injected into the cooling medium flow channel 9 under the action of gravity, and at the same time ensure that when the passive water injection baffle 3 is closed, it is just covered on the insulation layer flow channel water injection pipe inlet 8; at the same time, it also ensures that multiple passive water injection baffles 3 are opened at the same time under the action of the buoyancy of the cooling medium.

[0037] Among them, the water injection pipeline 7 includes a water injection outlet, which is arranged opposite to the water injection outlet and the water injection pipe inlet 8 of the insulation layer flow channel, and a non-active water injection baffle 3 is arranged between the water injection outlet and the water injection pipe inlet 8 of the insulation layer flow channel, and the non-active water injection baffle 3 is hinged to the water injection outlet; that is, in this embodiment, the non-active water injection baffle 3 is hinged to the water injection outlet through a hinge, and can rotate relative to the water injection outlet with the axis of the hinge as the rotation center.

[0038] Specifically, the cooling medium in this embodiment is water.

[0039] An insulation layer flow channel water injection outlet 10 is provided on the outer insulation layer 2 of the lower head of the pressure vessel. When the height of the cooling medium in the cooling medium flow channel 9 exceeds the height of the insulation layer flow channel water injection outlet 10, the cooling medium flows into the large space 11 of the containment through the insulation layer flow channel water injection outlet 10.

[0040] Among them, an insulation layer flow channel water injection outlet 10 is arranged on the outer insulation layer 2 of the lower head of the pressure vessel, so that the cooling medium in the cooling medium flow channel 9 is discharged from the insulation layer flow channel water injection outlet 10, which is used to discharge the cooling medium and entrained steam after cooling the lower head 1 of the pressure vessel into the large space 11 of the containment.

[0041] Specifically, part of the water discharged from the water injection outlet 10 of the heat-insulating layer flow channel is water vapor heated by the heat of the lower head 1 of the pressure vessel, and part of the water is cooling medium after cooling the lower head 1 of the pressure vessel.

[0042] The water injection cooling system also includes an elevated water tank 5 outside the containment and a connecting pipe 12, one end of the connecting pipe 12 is connected to the top of the elevated water tank 5 outside the containment, and the other end of the connecting pipe 12 passes through the concrete wall 4 of the containment and extends into the large space 11 of the containment. The water injection pipeline 7 also includes a water injection inlet, and the water injection inlet of the water injection pipeline 7 passes through the concrete wall 4 of the containment and is connected to the bottom of the elevated water tank 5 outside the containment.

[0043] Among them, one end of the connecting pipe 12 is connected to the top of the high-level water tank 15 outside the containment shell to balance the pressure between the high-level water tank 5 outside the containment shell and the large space 11 of the containment shell.

[0044] The high-level water tank 5 outside the containment vessel is used to store cooling medium.

[0045] The water injection cooling system further includes a valve 6 , and a valve 6 is provided on the water injection pipeline 7 located outside the containment concrete wall 4 .

[0046] Among them, a valve 6 is provided on the outer side of the water injection pipeline 7 located on the containment concrete wall 4, so that the operator can operate the valve 6 to open or close it easily.

[0047] Specifically, valve 6 is an isolation valve. Under normal operating conditions, valve 6 remains closed; under accident conditions, when the reactor cavity water injection measure is implemented, valve 6 is opened.

[0048] When the passive water injection baffle 3 is not pushed by the buoyancy of the cooling medium in the large containment space 11, the passive water injection baffle 3 covers the insulation layer flow channel water injection pipe inlet 8 to close the insulation layer flow channel water injection pipe inlet 8; when the passive water injection baffle 3 is pushed by the buoyancy of the cooling medium in the large containment space 11, the passive water injection baffle 3 is separated from the insulation layer flow channel water injection pipe inlet 8 to open the insulation layer flow channel water injection pipe inlet 8.

[0049] Among them, when the passive water injection baffle 3 is not pushed by the buoyancy of the cooling medium in the large space 11 of the containment shell, the passive water injection baffle 3 is covered on the water injection pipe inlet 8 of the insulation layer flow channel to close the water injection pipe inlet 8 of the insulation layer flow channel. That is to say, when the cooling medium is injected into the cooling medium flow channel 9 to cool the lower head 1 of the pressure vessel in the early stage, the height of the cooling medium in the large space 11 of the containment shell fails to generate buoyancy on the passive water injection baffle 3. At this time, the passive water injection baffle 3 is not pushed by the buoyancy generated by the cooling medium. Therefore, the passive water injection baffle 3 is covered on the water injection pipe inlet 8 of the insulation layer flow channel. At this time, the water injection pipe inlet 8 of the insulation layer flow channel is in a closed state, and the cooling medium injected into the cooling medium flow channel 9 is all provided by the high-level water tank 5 outside the containment shell, thereby realizing passive water injection cooling under the action of gravity.

[0050] Among them, when the passive water injection baffle 3 is pushed by the buoyancy of the cooling medium in the large space 11 of the containment, the passive water injection baffle 3 is separated from the inlet 8 of the water injection pipe of the thermal insulation layer flow channel, so that the inlet 8 of the water injection pipe of the thermal insulation layer flow channel is opened, that is, after a period of water injection, the cooling medium in the cooling medium flow channel 9 will be collected into the large space 11 of the containment through the water injection outlet 10 of the thermal insulation layer flow channel. When the height of the cooling medium can reach the buoyancy pushing force on the passive water injection baffle 3, the passive water injection baffle 3 is separated from the inlet 8 of the water injection pipe of the thermal insulation layer flow channel, and before the high-level water tank 5 outside the containment is emptied, the large space 11 of the containment is The cooling medium in the containment is directly injected into the cooling medium flow channel 9 from the opening between the water injection pipe inlet 8 of the thermal insulation layer flow channel and the passive water injection baffle 3. At the same time, the cooling medium in the high-level water tank 5 outside the containment is injected into the cooling medium flow channel 9 through the water injection pipeline 7 and the water injection pipe inlet 8 of the thermal insulation layer flow channel under the action of gravity, and the lower head 1 of the pressure vessel is cooled at the same time; after the high-level water tank 5 outside the containment is emptied, only the cooling medium in the large space 11 of the containment is directly injected into the cooling medium flow channel 9 from the opening between the water injection pipe inlet 8 of the thermal insulation layer flow channel and the passive water injection baffle 3, and the lower head 1 of the pressure vessel is cooled. The lower head 1 of the pressure vessel in the large space 11 of the containment is quickly submerged in a short time.

[0051] Specifically, when the reactor cavity water injection measures are implemented under normal operation or accident conditions and the cooling medium water level in the reactor cavity / containment large space 11 has not reached the height of the passive water injection baffle 3, it remains closed; when the reactor cavity water injection measures are implemented under accident conditions and the cooling medium water level in the reactor cavity / containment large space 11 reaches the height of the passive water injection baffle 3, the passive water injection baffle 3 is opened due to the buoyancy of the cooling medium, forming a passive natural circulation of the cooling medium.

[0052] The diameter of the water injection pipe inlet 8 of the thermal insulation layer flow channel is larger than the diameter of the water injection pipeline 7 .

[0053] Among them, the diameter of the insulation layer flow channel water injection pipe inlet 8 is larger than the diameter of the water injection pipeline 7, that is, when the passive water injection baffle 3 is opened, the opening between the insulation layer flow channel water injection pipe inlet 8 and the passive water injection baffle 3 is relatively large, so that the cooling medium in the large containment space 11 can quickly enter the cooling medium flow channel 9, so as to further ensure that in the case of the large containment space 11, the lower head 1 of the pressure vessel can be quickly submerged in a short time.

[0054] There are at least three passive water injection baffles 3, each of which includes a short side and a wide side. The short side of the passive water injection baffle 3 faces the water injection pipeline 7 and is hingedly connected to the water injection pipeline 7. The wide side of the passive water injection baffle 3 faces the insulation layer flow channel water injection pipe inlet 8 and is used to close or open the insulation layer flow channel water injection pipe inlet 8.

[0055] Among them, in this embodiment, three passive water injection baffles 3 are used as an example for explanation, namely the first passive water injection baffle, the second passive water injection baffle and the third passive water injection baffle, the second passive water injection baffle is at least partially overlapped on the first passive water injection baffle, the third passive water injection baffle is at least partially overlapped on the first passive water injection baffle, the first passive water injection baffle is at least partially overlapped on the third passive water injection baffle, when adjacent passive water injection baffles 3 overlap When the part is the smallest, the passive water injection baffle 3 covers the insulation layer flow channel water injection pipe inlet 8, and the insulation layer flow channel water injection pipe inlet 8 is in a closed state; when the adjacent passive water injection baffles 3 are pushed by the buoyancy of the cooling medium in the large containment space 11, and the overlapping part gradually increases, the passive water injection baffles 3 move toward the axial direction of the insulation layer flow channel water injection pipe inlet 8 and separate from the insulation layer flow channel water injection pipe inlet 8, and the insulation layer flow channel water injection pipe inlet 8 is in an open state. In other embodiments, the number of passive water injection baffles 3 can be reasonably adjusted according to specific working conditions.

[0056] The water injection cooling system provided by the present invention can better achieve the goal of submerging the lower head 1 of the pressure vessel in a short period of time, and has better pool cooling effect than the AP1000 power plant that directly submerges the reactor cavity / containment. Under the premise of not changing the size of the water injection pipeline 7, the cooling medium of the high-level water tank 5 outside the containment is injected into the cooling medium flow channel 9 by gravity through the water injection pipeline 7 in the early stage, and the lower head 1 of the pressure vessel is cooled in a one-time cooling manner. After the high-level water tank 5 outside the containment is emptied in the later stage, the non-active water injection baffle 3 is opened, and the cooling medium in the large space 11 of the containment is directly injected into the cooling medium flow channel 9 through the insulation layer flow channel water injection pipe inlet 8, so as to achieve long-term heat transfer by natural circulation.

[0057] The water injection cooling system provided by the present invention is used for external cooling of the reactor pressure vessel to maintain the integrity of the pressure vessel, thereby avoiding or alleviating the threats to the integrity of the containment caused by various dynamic loads such as direct heating of the containment, steam explosion outside the pressure vessel, interaction between molten material and concrete, and other accidents outside the pressure vessel, and avoiding further leakage of the molten material.

[0058] The water injection cooling system provided by the present invention adopts a fully passive containment / combustion cavity water injection scheme, which completely eliminates the dependence on active power supply compared to the prior art, improves the safety performance of the power plant and does not require a series of active equipment such as combustion cavity water injection pumps or water make-up pumps, thereby saving the economic cost of the power plant.

[0059] The water injection cooling system provided by the present invention eliminates the threat of bypassing the containment caused by the large-diameter water injection pipeline required to flood the large-space containment in a short period of time. For example, in the case of directly flooding the large-space containment, assuming that the flooding volume is 4000m3 within 1 hour, 3 , the required flow rate is 4000m 3 / h, the required pipe diameter is about 50cm; while in the water injection cooling system provided in this application, the volume to be flooded by water in the early stage is only 3m 3 Assuming that the water temperature of the high-level water tank 5 outside the containment is 50°C, the cooling medium is heated to 90°C after flowing through the cooling medium flow channel 9, and the required flow rate is only about 600m 3 / h, the required water injection pipeline 7 diameter is only 25cm, which is 50% smaller than the diameter of the water injection pipeline 7 required for directly flooding the large space containment, greatly improving the safety of the nuclear reactor.

[0060] A second aspect of the present embodiment provides a water injection cooling method, using any one of the above water injection cooling systems, comprising the following steps:

[0061] When the containment shell includes an external high-level water tank 5, the cooling medium in the external high-level water tank 5 is injected into the cooling medium flow channel 9 through the water injection pipeline 7 and the insulation layer flow channel water injection pipe inlet 8, and then the cooling medium flows out through the insulation layer flow channel water injection outlet 10 into the containment shell large space 11;

[0062] Before the high-level water tank 5 outside the containment is emptied, as the water level in the large containment space 11 continues to rise, the passive water injection baffle 3 is opened or closed; if the passive water injection baffle 3 is opened under the buoyancy of the cooling medium at this time, since the opening of the passive water injection baffle 3 is in the same direction as the water injection direction (see attached Figure 2 ), the influence of the passive water injection damper 3 opening on the cooling medium flow rate can be ignored. If the passive water injection damper 3 is closed at this time, the closing of the passive water injection damper 3 has no influence on the cooling medium flow rate.

[0063] When the passive water injection damper 3 is closed, only the high-level water tank 5 outside the containment injects the cooling medium into the cooling medium flow channel 9 to cool the lower head 1 of the pressure vessel;

[0064] When the passive water injection baffle 3 is opened under the action of buoyancy, the high-level water tank 5 outside the containment and the large containment space 11 simultaneously inject the cooling medium into the cooling medium flow channel 9 to cool the lower head 1 of the pressure vessel;

[0065] When the high-level water tank 5 outside the containment is emptied, the passive water injection baffle 3 is in an open state under the buoyancy of the cooling medium, and the cooling medium in the large space 11 of the containment enters the cooling medium flow channel 9 through the insulation layer flow channel water injection pipe inlet 8 to perform passive natural circulation cooling on the lower head 1 of the pressure vessel.

[0066] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0067] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A water injection cooling system, characterized in that: include: A pressure vessel lower head (1), wherein a pressure vessel lower head outer insulation layer (2) is arranged outside the pressure vessel lower head (1), and a cooling medium flow channel (9) is formed between the pressure vessel lower head (1) and the pressure vessel lower head outer insulation layer (2); The outer insulation layer (2) of the lower end cover of the pressure vessel is provided with an insulation layer flow channel water injection pipe inlet (8) protruding outwards; A water injection pipeline (7), the water injection pipeline (7) comprising a water injection outlet, the water injection outlet being arranged opposite to the water injection pipe inlet (8) of the thermal insulation layer flow channel, a passive water injection baffle (3) being arranged between the water injection outlet and the water injection pipe inlet (8) of the thermal insulation layer flow channel, the passive water injection baffle (3) being hinged to the water injection outlet; A large containment space (11), wherein the cooling medium in the large containment space (11) generates buoyancy to push the passive water injection baffle (3) to open, so that the cooling medium enters the cooling medium flow channel (9) to perform passive circulation cooling on the lower head (1) of the pressure vessel.

2. A water injection cooling system according to claim 1, characterized in that: When the passive water injection baffle (3) is not pushed by the buoyancy of the cooling medium in the large containment space (11), the passive water injection baffle (3) is covered on the insulation layer flow channel water injection pipe inlet (8) so that the insulation layer flow channel water injection pipe inlet (8) is closed; when the passive water injection baffle (3) is pushed by the buoyancy of the cooling medium in the large containment space (11), the passive water injection baffle (3) is separated from the insulation layer flow channel water injection pipe inlet (8) so that the insulation layer flow channel water injection pipe inlet (8) is opened.

3. A water injection cooling system according to claim 1, characterized in that: The diameter of the water injection pipe inlet (8) of the thermal insulation layer flow channel is larger than the diameter of the water injection pipeline (7).

4. A water injection cooling system according to claim 1, characterized in that: The number of the passive water injection baffles (3) is at least three, and the passive water injection baffles (3) include short sides and wide sides. The short sides of the passive water injection baffles (3) face the water injection pipeline (7) and are hingedly connected to the water injection pipeline (7). The wide sides of the passive water injection baffles (3) face the water injection pipe inlet (8) of the thermal insulation layer flow channel and are used to close or open the water injection pipe inlet (8) of the thermal insulation layer flow channel.

5. A water injection cooling system according to claim 1, characterized in that: An insulation layer flow channel water injection outlet (10) is provided on the outer insulation layer (2) of the lower head of the pressure vessel. When the height of the cooling medium in the cooling medium flow channel (9) exceeds the height of the insulation layer flow channel water injection outlet (10), the cooling medium flows into the large containment space (11) through the insulation layer flow channel water injection outlet (10).

6. A water injection cooling system according to claim 5, characterized in that: The water injection cooling system further comprises a high-level water tank (5) outside the containment and a connecting pipe (12), one end of the connecting pipe (12) being connected to the top of the high-level water tank (5) outside the containment, and the other end of the connecting pipe (12) penetrating the containment concrete wall (4) and extending into the large containment space (11), and the water injection pipeline (7) further comprises a water injection inlet, and the water injection inlet of the water injection pipeline (7) penetrating the containment concrete wall (4) and being connected to the bottom of the high-level water tank (5) outside the containment.

7. A water injection cooling system according to claim 6, characterized in that: The water injection cooling system further comprises a valve (6), and the water injection pipeline (7) is provided with a valve (6) at the outer portion of the containment concrete wall (4).

8. A water injection cooling method, characterized in that: The water injection cooling system according to any one of claims 1 to 7 comprises the following steps: When a high-level water tank (5) outside the containment is included, the cooling medium in the high-level water tank (5) outside the containment is injected into the cooling medium flow channel (9) through the water injection pipeline (7) and the insulation layer flow channel water injection pipe inlet (8), and then the cooling medium flows out through the insulation layer flow channel water injection outlet (10) into the large containment space (11); When the high-level water tank (5) outside the containment is emptied, the passive water injection baffle (3) is in an open state under the action of the buoyancy of the cooling medium, and the cooling medium in the large space (11) of the containment enters the cooling medium flow channel (9) through the water injection pipe inlet (8) of the thermal insulation layer flow channel, so as to perform passive natural circulation cooling on the lower head (1) of the pressure vessel.

9. A water injection cooling method according to claim 8, characterized in that: Before the high-level water tank (5) outside the containment vessel is emptied, as the water level in the large space (11) of the containment vessel continues to rise, the passive water injection baffle (3) is opened or closed.

10. A water injection cooling method according to claim 9, characterized in that: When the passive water injection baffle (3) is closed, only the high-level water tank (5) outside the containment vessel injects the cooling medium into the cooling medium flow channel (9); When the passive water injection baffle (3) is opened under the buoyancy of the cooling medium in the large containment space, the high-level water tank (5) outside the containment and the large containment space (11) simultaneously inject the cooling medium into the cooling medium flow channel (9).

Images