A passive and active reactor cavity water injection cooling system and method

Abstract

The present invention discloses a passive and active reactor cavity water injection cooling system and method, comprising an insulation layer, a reactor cavity compartment concrete wall and a containment concrete wall which are sequentially arranged on the outside of the lower head of the pressure vessel from the inside to the outside; an insulation layer flow channel is formed between the lower head of the pressure vessel and the insulation layer; a reactor cavity compartment is formed between the outer side of the insulation layer, the reactor cavity compartment concrete wall and the bottom surface of the containment concrete wall; an outer compartment is formed between the reactor cavity compartment concrete wall and the side surface of the containment concrete wall; a containment compartment is formed between the upper part of the reactor cavity compartment concrete wall and the top surface of the containment concrete wall; the outlet elevation of the insulation layer flow channel is higher than the elevation of the reactor cavity compartment concrete wall. The present invention can quickly submerge the lower head of the pressure vessel to take away the heat in the event of a serious accident in a nuclear reactor, thereby ensuring its integrity, avoiding the consequences of the release of molten material in the containment, and improving safety.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear reactor safety design, and in particular relates to a passive and active reactor cavity water injection cooling system and method. Background Art

[0002] In severe accidents, the fuel melts because the core is not sufficiently cooled. When the molten material in the core falls to the lower head of the pressure vessel to form a molten pool, the molten material generates a large amount of mechanical heat load, threatening the integrity of the lower head. The third-generation nuclear power technology adopts advanced severe accident mitigation measures, including the in-core retention (IVR) technology of the lower head molten material to prevent the loss of pressure vessel integrity. For example, Westinghouse's AP600 and AP1000, South Korea's APR1400 and China's "Hualong One" all adopt the reactor cavity water injection measure. The reactor cavity water injection measure of the passive power plant AP600 and AP1000 is to immerse the reactor pressure vessel in water through passive gravity water injection, and use the natural circulation flow in the reactor cavity to take away the heat of the lower head of the pressure vessel.

[0003] In order to reduce economic costs and dependence on active power sources, the design of reactor cavity water injection measures can adopt a passive + active approach. At the same time, for nuclear power plants with large containment compartments, the water injection flow rate required to completely flood the containment compartments in a short period of time is huge. Therefore, it is necessary to design a passive + active reactor cavity water injection measure tailored to the design characteristics of large containment compartments to achieve the purpose of IVR, ensure the integrity of the lower head of the pressure vessel, and prevent the release of molten material in the containment. Summary of the invention

[0004] In order to further reduce the dependence of reactor cavity water injection cooling measures on active power supply, the present invention provides a passive and active reactor cavity water injection cooling system. In the event of a serious accident in a nuclear reactor, the present invention quickly floods the lower head of the pressure vessel to remove heat, ensures its integrity, avoids the consequences of molten material being released in the containment, and improves safety.

[0005] The present invention is achieved through the following technical solutions:

[0006] A passive and active reactor cavity water injection cooling system, comprising a thermal insulation layer, a reactor cavity compartment concrete wall and a containment vessel concrete wall which are sequentially arranged on the outer side of the lower head of the pressure vessel from the inside to the outside;

[0007] A heat-insulating layer flow channel is formed between the lower head of the pressure vessel and the heat-insulating layer;

[0008] A reactor cavity compartment is formed between the outer side of the thermal insulation layer, the reactor cavity compartment concrete wall and the bottom surface of the containment concrete wall;

[0009] An outer compartment is formed between the reactor cavity compartment concrete wall and the side surface of the containment vessel concrete wall;

[0010] A containment compartment is formed between the upper portion of the reactor cavity compartment concrete wall and the top surface of the containment concrete wall;

[0011] The outlet elevation of the insulation layer flow channel is higher than the elevation of the concrete wall of the stack cavity compartment.

[0012] Preferably, the device of the present invention further comprises a high-level water tank arranged inside the concrete wall of the containment;

[0013] The elevation of the bottom of the high-level water tank is higher than the outlet of the insulation layer flow channel.

[0014] Preferably, a connecting channel is provided at the top of the high-level water tank of the present invention so that the pressure in the high-level water tank is balanced with the pressure in the containment compartment;

[0015] The bottom of the high-level water tank is communicated with the insulation layer flow channel in the reactor cavity compartment through a water injection pipe.

[0016] Preferably, the connecting channel of the present invention is provided with a filter screen to prevent impurities from entering the high-level water tank.

[0017] Preferably, the present invention provides a first isolation valve on the water injection pipe close to the outlet of the high-level water tank;

[0018] A second isolation valve is arranged on the water injection pipe located in the outer compartment.

[0019] Preferably, the device of the present invention further comprises an external water tank and a water injection pump arranged outside the concrete wall of the containment;

[0020] The outer water tank is connected to the insulation layer flow channel in the reactor compartment through a water injection pipe;

[0021] The water injection pump is arranged on a water injection pipe close to the outer water tank.

[0022] In a second aspect, the present invention provides a method for a passive and active reactor cavity water injection cooling system as described above, comprising:

[0023] After a serious accident occurs in a nuclear reactor, when the conditions for implementing reactor cavity water injection measures are met, reactor cavity water injection measures shall be implemented.

[0024] Preferably, the measures for implementing reactor cavity water injection of the present invention specifically include:

[0025] Manually open the first isolation valve on the water injection pipe at the outlet of the high-level water tank in the containment to implement a large-flow passive reactor cavity water injection measure;

[0026] When the water in the high-level water tank is emptied, the water injection pump provided on the water injection pipe of the outer water tank of the containment is turned on; the water in the outer water tank is injected into the flow channel of the insulation layer through the water injection pipe and the water injection pump;

[0027] When the water in the outer water tank is drained, the second isolation valve on the water injection pipe in the outer compartment is opened to implement long-term passive circulation cooling of the lower head of the pressure vessel.

[0028] Preferably, the measures for implementing high-flow passive reactor cavity water injection of the present invention are specifically:

[0029] The water in the high-level water tank is injected into the insulation layer flow channel through the water injection pipe; the cooling water flows through the insulation layer flow channel, and a part of the cooling water is heated by the heat of the lower head of the pressure vessel into water vapor and enters the containment compartment through the outlet of the insulation layer flow channel, condenses in the containment compartment, and gathers in the outer compartment; the remaining part enters the outer compartment through the outlet of the insulation layer flow channel.

[0030] Preferably, the long-term passive cyclic cooling of the lower head of the pressure vessel of the present invention is specifically implemented as follows:

[0031] After opening, the second isolation valve remains in the open state; the cooling water in the outer compartment enters the water injection pipe through the second isolation valve, and flows into the insulation layer flow channel through the water injection pipe. When flowing through the insulation layer flow channel, a part of the cooling water is heated by the heat of the lower head of the pressure vessel into water vapor and enters the containment compartment through the outlet of the insulation layer flow channel, condenses in the containment compartment, and gathers in the containment compartment; the remaining part enters the outer compartment through the outlet of the insulation layer flow channel.

[0032] The present invention has the following advantages and beneficial effects:

[0033] The present invention adopts passive + active reactor cavity water injection cooling measures. In the early stage, a high-level water tank in the containment is used for real-time large-flow, passive, and one-time passive water injection. After the high-level water tank is emptied, water is taken from the water tank outside the containment through a water injection pump. After the water tank outside the containment is emptied, the isolation valve in the containment compartment is opened to implement long-term circulation cooling.

[0034] The passive + active reactor cavity water injection cooling measures provided by the present invention can take away the heat of the lower head of the pressure vessel when a serious accident occurs in a nuclear reactor, thereby ensuring the integrity of the lower head of the pressure vessel.

[0035] Compared with the prior art, the present invention sets a large-capacity water tank outside the containment to save the containment space, adopts the active water injection method to take water from the water tank outside the containment, and the height of the water tank position can be freely set, avoiding the safety risks caused by the high position of the large-capacity water tank. At the same time, the setting of the high-position water tank in the containment buys time for the input of the active power supply and achieves the goal of flooding the lower head of the pressure vessel with the large-space containment in a short time, thereby improving the safety of the nuclear reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0037] Figure 1 It is a schematic diagram of the structure of the water injection cooling system of the present invention.

[0038] Figure 2 It is a schematic diagram of the cooling water circulation flow path of the present invention.

[0039] Marks and corresponding parts names in the attached drawings:

[0040] 1: External water tank; 2: Insulation layer; 3: Reactor cavity compartment concrete wall; 4: Concrete wall of containment vessel; 5: Reactor cavity compartment; 6: Lower head of pressure vessel; 7: Insulation layer flow channel; 8: High-level water tank; 9: Injection pump; 10: Injection pipe; 11: Insulation layer flow channel outlet; 12: First isolation valve; 13: External compartment; 14: Second isolation valve; 15: Containment compartment; 16: Connecting channel. DETAILED DESCRIPTION

[0041] Hereinafter, the term "include" or "may include" used in various embodiments of the present invention indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0042] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0043] The expressions (such as "first", "second", etc.) used in various embodiments of the present invention may modify the various constituent elements in various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing an element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of various embodiments of the present invention, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0044] It should be noted that if it is described that one component element is “connected” to another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0045] The terms used in various embodiments of the present invention are only used for the purpose of describing specific embodiments and are not intended to limit various embodiments of the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meaning generally understood by those of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in various embodiments of the present invention.

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0047] Example 1

[0048] In order to further eliminate the dependence on active power supply, buy time for the investment of active power supply and achieve the goal of submerging the lower head of the pressure vessel in a large space containment in a short time, this embodiment provides a passive and active reactor cavity water injection cooling system.

[0049] like Figure 1As shown, the system of this embodiment includes an insulation layer 2, a reactor cavity compartment concrete wall 3 and a containment concrete wall 4 which are arranged on the outside of the pressure vessel lower head 6 from the inside to the outside; the containment concrete wall 4 completely accommodates the pressure vessel lower head 6, the insulation layer 2, and the reactor cavity compartment concrete wall 3.

[0050] A thermal insulation layer flow channel 7 is formed between the lower head 6 of the pressure vessel and the thermal insulation layer 2 .

[0051] A reactor cavity compartment 5 is formed between the outer side of the thermal insulation layer 2 , the reactor cavity compartment concrete wall 3 and the bottom surface of the containment vessel concrete wall 4 .

[0052] An outer compartment 13 is formed between the reactor cavity compartment concrete wall 3 and the side surface of the containment vessel concrete wall 4 .

[0053] A containment compartment 15 is formed between the upper portion of the reactor cavity compartment concrete wall 3 and the top surface of the containment concrete wall 4 .

[0054] The elevation of the insulation layer flow channel outlet 11 is higher than the elevation of the reactor cavity compartment concrete wall 3 .

[0055] The system of this embodiment further comprises a high-level water tank 8 , which is arranged on the inner side of the containment concrete wall 4 , and the bottom elevation of the high-level water tank 8 is higher than the insulation layer flow channel outlet 11 .

[0056] A connecting channel 16 is provided on the top of the high-level water tank 8 to balance the pressure in the high-level water tank 8 with the pressure in the containment compartment 15; the bottom of the high-level water tank 8 is connected to the insulation layer flow channel 7 in the reactor compartment 5 through the water injection pipe 10, and a first isolation valve 12 is provided on the water injection pipe 10 near the outlet of the high-level water tank 8. A second isolation valve 14 is provided on the water injection pipe 10 located in the outer compartment 13. Under normal operating conditions, the first isolation valve 12 and the second isolation valve 14 are in a closed state.

[0057] The connecting channel 16 is provided with a filter screen to prevent impurities from entering the high-level water tank 8 .

[0058] The system of this embodiment further comprises an outer water tank 1 , which is connected to the insulation layer flow channel 7 via a water injection pipe 10 , and a water injection pump 9 is provided on the water injection pipe 10 near the water outlet of the outer water tank 1 .

[0059] The system working principle of this embodiment is:

[0060] Adopt real-time large flow, passive, one-pass passive water injection from high-level water tank in containment;

[0061] After the high-level water tank is emptied, water is taken from outside the containment through the water injection pump 9;

[0062] After the water tank 1 outside the containment vessel is emptied, the second isolation valve 12 on the water injection pipe in the outer compartment 13 is opened to perform long-term circulation cooling in real time.

[0063] Example 2

[0064] This embodiment adopts a passive and active reactor cavity water injection cooling system proposed in the above embodiment 1 to implement reactor cavity water injection cooling measures, specifically:

[0065] After a serious accident occurs in a nuclear reactor, when the conditions for implementing the reactor cavity water injection measures are met, the reactor cavity water injection measures are implemented. The specific process includes:

[0066] Step 1: manually open the first isolation valve 12 on the water injection pipe 10 at the outlet of the high-level water tank 8 in the containment to implement a large-flow passive reactor cavity water injection measure.

[0067] During the high-flow passive reactor cavity water injection measure: the water in the high-level water tank 8 is injected into the insulation layer flow channel 7 through the water injection pipe 10. The cooling water flows through the insulation layer flow channel 7 and flows out from the insulation layer flow channel outlet 11. The cooling water flows through the insulation layer flow channel 7, and a part of the cooling water is heated by the heat of the pressure vessel lower head 6 to become water vapor and enters the containment compartment 15 through the insulation layer flow channel outlet 11, condenses in the containment compartment 15, and gathers in the outer compartment 13; the remaining part enters the outer compartment 13 through the insulation layer flow channel outlet 11.

[0068] Step 2: After the water in the high-level water tank 8 is drained, turn on the water injection pump 9 provided on the water injection pipe 10 of the containment outer water tank 1; the water in the outer water tank 1 is injected into the insulation layer flow channel 7 through the water injection pipe 10 and the water injection pump 9.

[0069] Step 3: After the water in the outer water tank 1 is drained, the second isolation valve 14 on the water injection pipe 10 in the outer compartment 13 is opened to implement long-term passive circulation cooling of the lower head 6 of the pressure vessel.

[0070] The second isolation valve 14 remains in the open state after being opened. The cooling water in the outer compartment 13 enters the water injection pipe 10 through the second isolation valve 14, and flows into the insulation layer flow channel 7 through the water injection pipe 10. When flowing through the insulation layer flow channel 7, a part of the cooling water is heated by the heat of the pressure vessel lower head 6 to become water vapor, and enters the containment compartment 15 through the insulation layer flow channel outlet 11, condenses in the containment compartment 15, and gathers in the containment compartment 13; the remaining part enters the outer compartment 13 through the insulation layer flow channel outlet 11, as shown in FIG. Figure 2 shown.

[0071] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A passive and active reactor cavity water injection cooling system, characterized in that: It comprises a thermal insulation layer (2), a reactor cavity compartment concrete wall (3) and a containment vessel concrete wall (4) which are sequentially arranged on the outside of a lower head (6) of the pressure vessel from the inside to the outside; A thermal insulation layer flow channel (7) is formed between the lower end cover (6) of the pressure vessel and the thermal insulation layer (2); A reactor cavity compartment (5) is formed between the outer side of the thermal insulation layer (2), the reactor cavity compartment concrete wall (3) and the bottom surface of the containment vessel concrete wall (4); An outer compartment (13) is formed between the reactor cavity compartment concrete wall (3) and the side surface of the containment vessel concrete wall (4); A containment compartment (15) is formed between the upper portion of the reactor cavity compartment concrete wall (3) and the top surface of the containment concrete wall (4); The outlet (11) of the insulation layer flow channel has a higher elevation than the elevation of the reactor cavity compartment concrete wall (3); and further comprises a high-level water tank (8) arranged on the inner side of the containment concrete wall (4); The elevation of the bottom of the high-level water tank (8) is higher than the outlet (11) of the insulation layer flow channel; a connecting channel (16) is provided at the top of the high-level water tank (8) to balance the pressure in the high-level water tank (8) with the pressure in the containment compartment (15); The bottom of the high-level water tank (8) is connected to the insulation layer flow channel (7) in the reactor cavity compartment (5) through a water injection pipe; It also includes an external water tank (1) and a water injection pump (9) arranged outside the containment concrete wall (4); The outer water box (1) is connected to the insulation layer flow channel (7) in the reactor cavity compartment (5) through a water injection pipe; The water injection pump (9) is arranged on a water injection pipe close to the outer water tank (1); A first isolation valve (12) is provided on the water injection pipe close to the outlet of the high-level water tank (8); A second isolation valve (14) is provided on the water injection pipe located in the outer compartment (13).

2. A passive and active reactor cavity water injection cooling system according to claim 1, characterized in that: The connecting channel (16) is provided with a filter screen to prevent impurities from entering the high-level water tank (8).

3. A method for using a passive and active reactor cavity water injection cooling system according to any one of claims 1 to 2, characterized in that: include: After a serious accident occurs in a nuclear reactor, when the conditions for implementing reactor cavity water injection measures are met, reactor cavity water injection measures shall be implemented.

4. The method according to claim 3, characterized in that The specific measures for implementing reactor cavity water injection include: Manually open the first isolation valve on the water injection pipe at the outlet of the high-level water tank in the containment to implement a large-flow passive reactor cavity water injection measure; When the water in the high-level water tank is emptied, the water injection pump provided on the water injection pipe of the outer water tank of the containment is turned on; the water in the outer water tank is injected into the flow channel of the insulation layer through the water injection pipe and the water injection pump; When the water in the outer water tank is emptied, the second isolation valve on the water injection pipe in the outer compartment is opened to implement long-term passive circulation cooling of the lower head of the pressure vessel.

5. The method according to claim 4, characterized in that The specific measures for implementing large-flow passive reactor cavity water injection are: The water in the high-level water tank is injected into the insulation layer flow channel through the water injection pipe; the cooling water flows through the insulation layer flow channel, and a part of the cooling water is heated by the heat of the lower head of the pressure vessel into water vapor and enters the containment compartment through the outlet of the insulation layer flow channel, condenses in the containment compartment, and gathers in the outer compartment; the remaining part enters the outer compartment through the outlet of the insulation layer flow channel.

6. The method according to claim 4, characterized in that The implementation of long-term passive circulation cooling of the lower head of the pressure vessel is as follows: After opening, the second isolation valve remains in the open state; the cooling water in the outer compartment enters the water injection pipe through the second isolation valve, and flows into the insulation layer flow channel through the water injection pipe. When flowing through the insulation layer flow channel, a part of the cooling water is heated by the heat of the lower head of the pressure vessel into water vapor and enters the containment compartment through the outlet of the insulation layer flow channel, condenses in the containment compartment, and gathers in the containment compartment; the remaining part enters the outer compartment through the outlet of the insulation layer flow channel.

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