阅读说明：本技术 一种安全注入系统及核电站 (Safe injection system and nuclear power station ) 是由 盛美玲 李洁垚 唐辉 张艳娥 丘锦萌 孙娜 于 2019-03-13 设计创作，主要内容包括：本发明实施例提供一种安全注入系统及核电站,安全注入系统应用于核电站,核电站包括反应堆压力容器、N个蒸汽发生器及N个热管段,每个蒸汽发生器通过一个热管段与反应堆压力容器连接,安全注入系统包括N个安全注入单元、N个直接注入管线及N个热段注入管线,N为正整数,且N大于1,每个安全注入单元通过一个直接注入管线及一个热段注入管线与反应堆压力容器连接,安全注入单元包括：安注箱,安注箱通过直接注入管线与反应堆压力容器连接；安注泵,安注泵包括第一出口管及第二出口管,第一出口管通过直接注入管线与反应堆压力容器连接,第二出口管通过热段注入管线与热管段连接。本发明实施例提供的安全注入系统的可靠性较高。(The embodiment of the invention provides a safety injection system and a nuclear power station, wherein the safety injection system is applied to the nuclear power station, the nuclear power station comprises a reactor pressure vessel, N steam generators and N heat pipe sections, each steam generator is connected with the reactor pressure vessel through one heat pipe section, the safety injection system comprises N safety injection units, N direct injection pipelines and N heat section injection pipelines, N is a positive integer and is more than 1, each safety injection unit is connected with the reactor pressure vessel through one direct injection pipeline and one heat section injection pipeline, and the safety injection unit comprises: the safety injection box is connected with the reactor pressure vessel through a direct injection pipeline; the safety injection pump comprises a first outlet pipe and a second outlet pipe, the first outlet pipe is connected with the reactor pressure vessel through a direct injection pipeline, and the second outlet pipe is connected with the heat pipe section through a heat section injection pipeline. The safety injection system provided by the embodiment of the invention has higher reliability.)

1. A safety injection system for a nuclear power plant, the nuclear power plant including a reactor pressure vessel, N steam generators and N heat pipe sections, each steam generator being connected to the reactor pressure vessel via a heat pipe section, the safety injection system including N safety injection units, N direct injection lines and N hot section injection lines, N being a positive integer and N being greater than 1, each safety injection unit being connected to the reactor pressure vessel via a direct injection line and a hot section injection line, the safety injection unit comprising:

the safety injection box is connected with the reactor pressure vessel through a direct injection pipeline;

and the safety injection pump comprises a first outlet pipe and a second outlet pipe, the first outlet pipe is connected with the reactor pressure vessel through the direct injection pipeline, and the second outlet pipe is connected with the heat pipe section through a heat section injection pipeline.

2. The safety injection system of claim 1, wherein the safety injection pump further comprises a third outlet pipe, the safety injection unit further comprising a return line, one end of the return line being connected to the third outlet pipe, the other end of the return line being connected to a water tank.

3. The safety injection system of claim 1, wherein the nuclear power plant further comprises N power supply systems, each safety injection unit is connected to one power supply system, the power supply systems are used for providing power supplies for the safety injection pumps, and the N power supply systems are independent of each other.

4. The safety injection system of claim 1, further comprising a water tank, wherein the safety injection pump further comprises a first inlet tube, and wherein the first inlet tubes of the safety injection pumps of the N safety injection units are each connected to the water tank.

5. The safety injection system of claim 1, wherein the safety injection pump further comprises a fourth outlet pipe, the safety injection unit further comprises a pH adjusting device, an inlet end of the pH adjusting device is connected with the fourth outlet pipe, and an outlet end of the pH adjusting device is connected with the water tank.

6. The safe injection system of claim 5, wherein the inlet end and the outlet end of the pH adjustment device are provided with isolation valves.

7. The safety injection system of claim 1, wherein the safety injection pump is configured to inject a first coolant into the reactor pressure vessel when the pressure of the water within the reactor pressure vessel is below a first predetermined pressure; and/or the safety injection box is used for injecting a second coolant into the reactor pressure vessel when the pressure of water in the reactor pressure vessel is lower than the pressure in the safety injection box.

8. The safety injection system of claim 2, wherein isolation valves and check valves are disposed on the direct injection line, the hot leg injection line, and the return line.

9. The safe injection system of claim 1, wherein the value of N is 2.

10. A nuclear power plant comprising a reactor pressure vessel, N steam generators and N heat pipe sections, each steam generator being connected to the reactor pressure vessel by one heat pipe section, the nuclear power plant further comprising a safety injection system as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the field of safety facility design of a nuclear power plant, in particular to a safety injection system and a nuclear power plant.

Background

Safety injection systems are important systems for maintaining the safety of nuclear power plants. When a break accident occurs to a primary circuit, the safety injection system is started to inject coolant into the reactor core so as to ensure that the reactor core is well cooled and avoid more serious nuclear safety accidents caused by the break accident.

The existing safety injection system generally comprises a medium-pressure safety injection pump and a low-pressure safety injection pump which are arranged in parallel, wherein outlet pipes of the medium-pressure safety injection pump and the low-pressure safety injection pump which are connected in parallel are respectively communicated to a reactor pressure vessel through a heat pipe section and a cold pipe section, and if the outlet pipes connected in parallel are damaged, the safety injection system fails, so that the safety injection system in the prior art is low in reliability.

Disclosure of Invention

The embodiment of the invention provides a safe injection system and a nuclear power station, and aims to solve the problem that the safe injection system in the prior art is low in reliability.

In order to solve the technical problem, the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides a safety injection system, which is applied to a nuclear power plant, where the nuclear power plant includes a reactor pressure vessel, N steam generators, and N heat pipe sections, each steam generator is connected to the reactor pressure vessel through one heat pipe section, the safety injection system includes N safety injection units, N direct injection lines, and N hot section injection lines, N is a positive integer and N is greater than 1, each safety injection unit is connected to the reactor pressure vessel through one direct injection line and one hot section injection line, and the safety injection unit includes:

the safety injection box is connected with the reactor pressure vessel through a direct injection pipeline;

and the safety injection pump comprises a first outlet pipe and a second outlet pipe, the first outlet pipe is connected with the reactor pressure vessel through the direct injection pipeline, and the second outlet pipe is connected with the heat pipe section through a heat section injection pipeline.

Optionally, the safety injection pump further comprises a third outlet pipe, the safety injection unit further comprises a return pipeline, one end of the return pipeline is connected with the third outlet pipe, and the other end of the return pipeline is connected with the water tank.

Optionally, the nuclear power plant further includes N power supply systems, each safety injection unit is connected to one power supply system, the power supply system is configured to provide a power supply for the safety injection pump, and the N power supply systems are independent of each other.

Optionally, the safety injection system further includes a water tank, the safety injection pump further includes a first inlet pipe, and the first inlet pipes of the safety injection pumps of the N safety injection units are all connected to the water tank.

Optionally, the safety injection pump further comprises a fourth outlet pipe, the safety injection unit further comprises a pH value adjusting device, an inlet end of the pH value adjusting device is connected with the fourth outlet pipe, and an outlet end of the pH value adjusting device is connected with the water tank.

Optionally, the inlet end and the outlet end of the pH adjusting device are both provided with an isolation valve.

Optionally, when the pressure of the water in the reactor pressure vessel is lower than a first preset pressure, the safety injection pump is used for injecting a first coolant into the reactor pressure vessel; and/or the safety injection box is used for injecting a second coolant into the reactor pressure vessel when the pressure of water in the reactor pressure vessel is lower than the pressure in the safety injection box.

Optionally, the direct injection line, the hot leg injection line, and the return line are provided with isolation valves and check valves.

Optionally, the value of N is 2.

In a second aspect, an embodiment of the present invention provides a nuclear power plant, where the nuclear power plant includes a reactor pressure vessel, N steam generators, and N heat pipe sections, and each steam generator is connected to the reactor pressure vessel through one heat pipe section.

In the embodiment of the invention, the coolant is injected into the reactor pressure vessel through the direct injection pipeline and the hot section injection pipeline, so that the flow share of the coolant entering the reactor pressure vessel is improved in the cold section breakage accident; and the coolant is injected through the plurality of safety injection units, so that the situation that the safety injection system is unavailable due to the fact that a safety injection box or a safety injection pump is unavailable in a single safety injection unit is avoided, and the reliability of the safety injection system provided by the embodiment of the invention is high.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a safety injection system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a safety injection system according to an embodiment of the present invention, where the safety injection system is applied to a nuclear power plant, the nuclear power plant includes a reactor pressure vessel 1, N steam generators 2 and N heat pipe sections 8, each steam generator 2 is connected to the reactor pressure vessel 1 through one heat pipe section 8, as shown in fig. 1, the safety injection system includes N safety injection units, N direct injection lines 7 and N hot section injection lines 9, N is a positive integer and N is greater than 1, each safety injection unit is connected to the reactor pressure vessel 1 through one direct injection line 7 and one hot section injection line 9, and the safety injection unit includes:

the safety injection box 4 is connected with the reactor pressure vessel 1 through a direct injection pipeline 7;

and the safety injection pump 3 comprises a first outlet pipe and a second outlet pipe, the first outlet pipe is connected with the reactor pressure vessel 1 through the direct injection pipeline 7, and the second outlet pipe is connected with the heat pipe section 8 through a heat section injection pipeline 9.

The steam generator 2 is used for generating steam through heat generated by the reactor pressure vessel 1, and then the generated steam pushes a turbine generator to generate electricity. The heat that the reactor core in the reactor pressure vessel 1 produced heats the water in the reactor pressure vessel 1, and the high temperature water in the reactor pressure vessel 1 gets into steam generator 2, heats the feedwater of secondary side in steam generator 2 to steam production, thereby drive turbo generator electricity generation, the high temperature water in the reactor pressure vessel 1 returns to reactor pressure vessel 1 through the cold leg section after being cooled down simultaneously. The heat pipe section 8 is used for communicating the steam generator 2 with the reactor pressure vessel 1. The reactor pressure vessel 1 is also in communication, via a cold pipe section, with a main pump for driving coolant to circulate within the coolant system of the reactor pressure vessel 1. Preferably, the direct injection line 7 may be arranged in the vicinity of the cold leg.

Wherein each safety injection unit is connected to the reactor pressure vessel 1 by a direct injection line 7, the N safety injection units are all different from the direct injection line 7 to which the reactor pressure vessel 1 is connected, and each safety injection unit is further connected to the reactor pressure vessel 1 by a heat pipe section 8, the N safety injection units are all different from the heat pipe section 8 to which the reactor pressure vessel 1 is connected.

Wherein, the safety injection tank 4 and the safety injection pump 3 are both used for providing coolant for the reactor pressure vessel 1, preferably, the coolant is water, preferably, boron-containing water. The outlet pipe of the safety injection tank 4 is connected with the direct injection pipeline 7, and an isolation valve 11 and a check valve 12 can be arranged on the outlet pipe of the safety injection tank 4, wherein the isolation valve 11 is in an open state. The top of the safety injection tank 4 is filled with nitrogen gas at a preset pressure value, the nitrogen gas is suspended above the coolant, and the preset pressure value can be 2MPa, or can be 4MPa, or can be 6MPa and the like. When the nuclear power plant normally works, the pressure value of nitrogen in the safety injection box 4 is lower than that of water in the reactor pressure vessel 1, and the safety injection box 4 is in a closed state and does not output coolant to the reactor pressure vessel 1. When an accident occurs in the nuclear power plant, the pressure value in the reactor pressure vessel 1 is reduced and is lower than the pressure value of nitrogen in the safety injection tank 4, and the coolant in the safety injection tank 4 is injected into the reactor pressure vessel 1 through the direct injection pipeline 7.

In practical applications, if an Accident occurs in the nuclear power plant, such as a Loss of Coolant Accident (LOCA), a Steam Generator Tube break (SGTR) Accident, etc., a safety injection signal is triggered, the safety injection pump 3 is activated after receiving the safety injection signal, the Coolant is pumped from the water tank 5, and the safety injection pump 3 injects the Coolant into the reactor pressure vessel 1 through the direct injection line 7 and injects the Coolant into the reactor pressure vessel 1 through the hot leg injection line 9. When the safety injection pump 3 reduces the pressure value in the reactor pressure vessel 1 to be lower than the preset pressure value of the safety injection tank 4, the safety injection tank 4 is started, and the coolant in the safety injection tank 4 is injected into the reactor pressure vessel 1 through the direct injection pipeline 7. When no accident occurs in the nuclear power plant, the safety injection system cannot be started and is in a standby state.

For example, the safety injection tank 4 is activated when the pressure value of water in the reactor pressure vessel 1 is lower than 4MPa, the safety injection pump 3 is activated when the pressure value of water in the reactor pressure vessel 1 is 10MPa, the pressure value of water in the reactor pressure vessel 1 is reduced from 10MPa to less than 4MPa by the safety injection pump 3, at this time, the safety injection tank 4 is activated, and the safety injection pump 3 and the safety injection tank 4 simultaneously inject coolant into the core of the reactor pressure vessel 1 to ensure that the core is well cooled.

It should be noted that, in the safety injection system in the prior art, coolant is injected into the reactor pressure vessel 1 through the cold leg injection pipeline, and when a cold leg is broken, the coolant cannot be injected into the reactor pressure vessel 1 through the cold leg injection pipeline via the cold leg, so that the corresponding safety injection unit is not available in the cold leg breakage accident. And the coolant is injected into the reactor pressure vessel 1 through the cold leg injection line and the hot leg injection line 9, which may result in a reduction in the flow share of the coolant injected into the reactor pressure vessel 1 by the safety injection system in the event of a cold leg break. In the embodiment of the invention, the coolant is injected into the reactor pressure vessel 1 through the direct injection pipeline 7 and the hot section injection pipeline 9, and the flow share of the coolant entering the reactor pressure vessel 1 is improved in a cold section break accident; and the coolant is injected through a plurality of safety injection units, so that the situation that the safety injection system is unavailable due to the fact that the safety injection box 4 or the safety injection pump 3 is unavailable in a single safety injection unit is avoided, and the reliability of the safety injection system provided by the embodiment of the invention is high.

Optionally, the safety injection pump 3 further includes a third outlet pipe, the safety injection unit further includes a return line 10, one end of the return line 10 is connected to the third outlet pipe, and the other end of the return line 10 is connected to the water tank 5.

Wherein the return line 10 may be a low flow return line 10, the flow of liquid through the line in the return line 10 being low. When the safety injection pump 3 starts or stops working, residual coolant in the pipeline flows back to the water tank 5 through the return pipeline 10, and the safety injection pump 3 can be protected.

Optionally, the nuclear power plant further includes N power supply systems, each safety injection unit is connected to one power supply system, the power supply system is configured to provide a power supply for the safety injection pump 3, and the N power supply systems are independent of each other. When one power supply system breaks down, the other N-1 power supply systems can also work normally, and the reliability of the safety injection system can be further improved.

Optionally, the safety injection system further includes a water tank 5, the safety injection pump 3 further includes a first inlet pipe, and the first inlet pipes of the safety injection pumps 3 of the N safety injection units are all connected to the water tank 5.

Wherein, water tank 5 can provide the coolant for safety injection pump 3, the safety injection pump 3 of N safety injection unit all draws the coolant from water tank 5 in. An isolation valve 11 may be disposed on the first inlet pipe, and the isolation valve 11 may be in a normally open state to keep the first inlet pipe full of coolant, so as to facilitate the safety injection pump 3 to quickly enter an operating state.

Optionally, the safety injection pump 3 further includes a fourth outlet pipe, the safety injection unit further includes a pH adjusting device 6, an inlet end of the pH adjusting device 6 is connected to the fourth outlet pipe, and an outlet end of the pH adjusting device 6 is connected to the water tank 5.

The structure form of the pH adjusting device 6 is not limited, and may be a mesh structure, a perforated structure, or the like. The expression form of the pH adjusting agent in the pH adjusting device 6 is not limited, and may be sodium hydroxide, trisodium phosphate, or the like. In a specific embodiment, the coolant is water, and in the event of a loss of coolant accident in a nuclear power plant, the water with radioactivity in the reactor pressure vessel 1 enters the containment vessel and flows into the water tank 5 through a series of return channels. The water in the water tank 5 is used as cooling water for accidents of the nuclear power plant, and the pH value of the water needs to be controlled. Therefore, it is necessary to utilize the pH adjusting device 6 in order to accomplish the control of the pH of the water in the water tank 5, control the retention of the radionuclide in the water tank 5 and prevent corrosion of the equipment in the containment. Meanwhile, the pH value adjusting device 6 and the return pipeline 10 are arranged in parallel, water in the safety injection pump 3 flows into the water tank 5 through the pH value adjusting device 6 through a fourth outlet pipe, additional active equipment such as pumps and the like is not needed, and the configuration is simple.

The pH value of the water in the water tank 5 is controlled by the pH value adjusting device 6, so that the equipment in the containment can be protected from being corroded.

Optionally, the inlet end and the outlet end of the pH adjusting device 6 are both provided with an isolation valve 11.

Wherein, under the condition that the safe injection system is not started, the isolating valves 11 on the inlet end and the outlet end of the pH value adjusting device 6 are in a closed state. When an accident of the nuclear power plant occurs, the safety injection system is started, and in the later stage of the development of the accident, the isolation valves 11 on the inlet end and the outlet end of the pH value adjusting device 6 are both in an open state, so that the control of the pH value of the liquid in the water tank 5 is completed.

The pH value adjusting device 6 is controlled to be opened and closed through the isolating valve 11, the structure is simple, and the realization is convenient.

Optionally, when the pressure of the water in the reactor pressure vessel 1 is lower than a first preset pressure, the safety injection pump 3 is used for injecting a first coolant into the reactor pressure vessel 1; and/or, the safety injection tank 4 is used for injecting a second coolant into the reactor pressure vessel 1 when the pressure of the water in the reactor pressure vessel 1 is lower than the pressure in the safety injection tank 4.

Wherein the first preset pressure is greater than the second preset pressure, and the first preset pressure may be 10Mpa, or may be 12Mpa, and so on. The second predetermined pressure may be 4Mpa, or may be 6Mpa, or may be so. The first coolant and the second coolant may be the same or different. In a specific embodiment, when the nuclear power plant normally operates, the pressure value of water in the reactor pressure vessel 1 is higher than 15MPa, when a coolant loss accident occurs in the nuclear power plant and the pressure value of the water in the reactor pressure vessel 1 is lower than 10MPa, the safety injection pump 3 is started, the pressure value of the water in the reactor pressure vessel 1 is reduced from 10MPa to below 4MPa through the safety injection pump 3, at the moment, the safety injection tank 4 is started, and the safety injection pump 3 and the safety injection tank 4 simultaneously inject coolant into the reactor core of the reactor pressure vessel 1 so as to ensure that the reactor core is well cooled.

In the embodiment of the invention, when the pressure of the water in the reactor pressure vessel 1 is lower than a first preset pressure, the safety injection pump 3 is used for injecting a first coolant into the reactor pressure vessel 1; and/or when the pressure of the water in the reactor pressure vessel 1 is lower than the pressure in the safety injection tank 4, the safety injection tank 4 is used for injecting a second coolant into the reactor pressure vessel 1, and the safety injection system of the embodiment of the invention can well realize the core cooling of the reactor pressure vessel 1.

Optionally, an isolation valve 11 and a check valve 12 are disposed on the direct injection line 7, the hot leg injection line 9 and the return line 10.

Wherein, the flow of the coolant flowing through the direct injection pipeline 7 is relatively large, and the isolation valve 11 on the direct injection pipeline 7 is in an open state, so that the safety injection pump 3 can rapidly inject a large amount of coolant into the reactor pressure vessel 1 through the direct injection pipeline 7 when the safety injection system is required to be put into operation. When the safety injection system requires maintenance inspection, the isolation valve 11 on the direct injection line 7 is in a closed state, facilitating maintenance inspection. The isolation valve 11 on the hot leg injection line 9 is in a closed state when the safety injection system is in a standby state, and the isolation valve 11 on the hot leg injection line 9 is in an open state when the safety injection system is activated. The isolation valve 11 on the return pipeline 10 is in an open state, so that the safety injection pump 3 is always in a standby state to ensure that the safety injection pump 3 is normally started, and the closing pressure head of the safety injection pump 3 is effectively controlled.

Optionally, the value of N is 2.

As shown in fig. 1, the safety injection system includes a first safety injection unit 13 and a second safety injection unit 14.

The embodiment of the invention also provides a nuclear power station, which comprises a reactor pressure vessel 1, N steam generators 2 and N heat pipe sections 8, wherein each steam generator 2 is connected with the reactor pressure vessel 1 through one heat pipe section 8, and the nuclear power station also comprises the safety injection system of the embodiment. The specific structure of the safety injection system is described in detail in the above embodiments, and can achieve the same beneficial effects, and therefore, the detailed description is omitted in this embodiment.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

In the description of the present invention, it is to be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that the terms "mounted," "disposed," and "connected" are to be construed broadly unless otherwise explicitly stated or limited. For example, the connection can be fixed, detachable or integrated; may be directly connected or indirectly connected through an intermediate. The fixed connection can be common technical schemes such as welding, threaded connection and clamping. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.