阅读说明：本技术 地下核电站内置冷却塔式安全壳内非能动冷却系统及方法 (Passive cooling system and method in built-in cooling tower type containment of underground nuclear power station ) 是由 钮新强 袁博 喻飞 苏毅 刘爽 刘凯 汪建 肖固城 陈玉梅 邓超 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种地下核电站内置冷却塔式安全壳内非能动冷却系统。它包括高位应急冷却水池、冷却水流量分配环路、冷却装置、冷却水再循环散热系统,安全壳为内部设置有上下柱状通孔的圆柱状密封壳体；柱状通孔内设置冷却装置；高位应急冷却水池的底部高程大于冷却水流量分配环路的高程；高位应急冷却水池、冷却水流量分配环路、冷却装置、冷却水再循环散热系统依次连接呈闭合的回路。本发明具有能实现地下核电站安全壳的非能动冷却功能的优点。本发明还公开了所述的地下核电站内置冷却塔式安全壳内非能动冷却系统的冷却方法。(The invention discloses a passive cooling system in a built-in cooling tower type containment of an underground nuclear power station. The containment is a cylindrical sealed shell with an upper cylindrical through hole and a lower cylindrical through hole arranged inside; a cooling device is arranged in the columnar through hole; the bottom elevation of the high-level emergency cooling water pool is greater than the elevation of the cooling water flow distribution loop; the high-level emergency cooling water pool, the cooling water flow distribution loop, the cooling device and the cooling water recycling and heat dissipation system are sequentially connected to form a closed loop. The passive cooling device has the advantage of realizing the passive cooling function of the containment vessel of the underground nuclear power station. The invention also discloses a cooling method of the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station.)

1. Passive cooling system in the built-in cooling tower type containment of underground nuclear power station, its characterized in that: comprises a high-level emergency cooling water pool (1), a cooling water flow distribution loop (2), a cooling device (3) and a cooling water recycling and heat dissipation system (4),

the containment (5) is a cylindrical sealed shell with a cylindrical through hole (5.1) arranged inside;

a cooling device (3) is arranged in the columnar through hole (5.1);

the bottom elevation of the high-level emergency cooling water pool (1) is greater than the elevation of the cooling water flow distribution loop (2);

the high-level emergency cooling water pool (1), the cooling water flow distribution loop (2), the cooling device (3) and the cooling water recycling and heat dissipation system (4) are sequentially connected to form a closed loop.

2. The in-containment passive cooling system of an in-containment cooling tower of an underground nuclear power plant as recited in claim 1, further comprising: the columnar through hole (5.1) is arranged in the middle of the containment (5);

one or more of the columnar through holes (5.1) are arranged.

3. The in-containment passive cooling system of an in-containment cooling tower of an underground nuclear power plant as claimed in claim 1 or 2, wherein: the columnar through hole (5.1) is in a cylindrical structure or a round platform-shaped structure.

4. The in-containment passive cooling system of an in-containment cooling tower of an underground nuclear power plant as recited in claim 3, further comprising: the cooling device (3) is selected from a containment built-in cooling tower.

5. The in-containment passive cooling system of an underground nuclear power plant internal cooling tower according to claim 4, characterized in that: the cooling device (3) comprises a plurality of cooling pipes (3.1), and the plurality of cooling pipes (3.1) are crisscrossed to form a cooling pipe network; the cooling pipe network is attached to the inner wall surface of the columnar through hole (5.1);

the inlet of the cooling pipe (3.1) is connected with the cooling water flow distribution loop (2), and the outlet is connected with the cooling water recycling heat dissipation system (4).

6. The in-containment passive cooling system of an in-containment cooling tower of an underground nuclear power plant as recited in claim 5, further comprising: the cooling water flow distribution loop (2) comprises a flow regulating valve (2.1) and a cooling water pipe (2.2);

the water inlet of the cooling water pipe (2.2) is connected with the water outlet of the high-level emergency cooling water pool, and the water outlet is connected with the water inlet of the cooling pipe (3.1);

the flow regulating valve (2.1) is arranged on the cooling water pipe (2.2);

the cooling water pipe (2.2) is provided with a plurality of pipes.

7. The in-containment passive cooling system of an in-containment cooling tower of an underground nuclear power plant as recited in claim 6, further comprising: the cooling water recycling heat dissipation system (4) comprises a cooling water flow control valve group (4.1), a cooling water radioactivity detection device (4.2), a circulating water pump (4.3), a radiator (4.4) and a temperature detection device (4.5);

the cooling water flow control valve bank (4.1), the cooling water radioactivity detection device (4.2), the circulating water pump (4.3), the radiator (4.4) and the temperature detection device (4.5) are sequentially connected;

the cooling water flow control valve group (4.1) is connected with the outlet of the cooling pipe (3.1);

the temperature detection device (4.5) is connected with the inlet of the high-level emergency cooling water pool (1).

8. The cooling method of the in-containment passive cooling system of the underground nuclear power plant built-in cooling tower type according to any one of claims 1 to 7, characterized by comprising the following steps: comprises the following steps of (a) carrying out,

when LOCA or a steam pipeline in the containment breaks, high-temperature and high-pressure steam is sprayed into the containment, and a passive cooling system in the built-in cooling tower type containment is triggered to start;

the method comprises the following steps: the low-temperature cooling water in the high-level emergency cooling water pool (1) flows into a cooling water flow distribution loop (2) under the action of gravity, and flows into a built-in cooling device (3) after being subjected to flow distribution through the cooling water flow distribution loop (2);

step two: when cooling water flows in a cooling pipe network of the cooling device (3), the heat in the containment (5) is transferred to the cooling water through the heat transfer process of condensation heat exchange of the inner wall surface (5.2) of the containment, heat conduction of the inner wall surface (5.2) of the containment and convection heat exchange of the outer wall surface (5.3) of the containment, at the moment, the heat in the containment (5) is reduced, the temperature and the pressure are reduced, and the temperature of the cooling water in the cooling pipe network is increased;

step three: the heated cooling water flows out of the cooling pipe network and is collected to a cooling water recycling heat dissipation system (4), and the collected cooling water is detected for radioactivity through a cooling water radioactivity detection device (4.2);

when the radioactivity of the collected cooling water is normal, the cooling water enters a radiator (4.4) through a circulating water pump (4.3) for cooling, and is injected into a high-level emergency cooling water pool (1) for recirculation after being cooled;

and when the radioactivity of the collected cooling water exceeds the standard, the cooling water enters a wastewater treatment system for treatment.

Technical Field

The invention relates to the technical field of nuclear power, in particular to a passive cooling system in a built-in cooling tower type containment of an underground nuclear power station. The invention also relates to a passive cooling method in the built-in cooling tower type containment of the underground nuclear power station, in particular to a cooling method of the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station.

Background

The containment vessel is used as a fourth barrier of the nuclear power station, and the integrity of the containment vessel under the accident condition is of great importance to the safety of the whole nuclear power station. When a LOCA or steam pipeline in the containment vessel is broken, high-temperature and high-pressure steam is sprayed into the containment vessel, so that the pressure and the temperature in the containment vessel are increased, the containment vessel is broken under overpressure, and a large amount of radioactive substances are leaked. Therefore, a containment cooling system is generally arranged in a ground nuclear power station to reduce the temperature and pressure of a containment under accident conditions such as LOCA (local area of the ocean), for example, an M310 reactor type is provided with an in-containment spraying system to reduce the pressure and temperature in the containment by spraying condensed steam; the AP1000 is provided with a passive containment cooling system, and transfers heat in the containment to the atmosphere outside the containment through a steel containment by natural forces such as gravity.

The underground nuclear power station is characterized in that the whole or part of the nuclear power station is arranged in an underground engineering cave, the safety barrier of the nuclear reactor is increased by using rock and engineering measures, and the possibility of releasing a large amount of radioactive substances to the environment is reduced. The researchers propose that the underground nuclear power station can cancel an outer layer concrete containment vessel in the general sense, the underground nuclear power station containment vessel is formed by using a steel lining and cavern surrounding rocks, the functions of providing the conventional outer layer concrete containment vessel can be effectively utilized by using the radioactive containment and the external event interference resistance of the cavern surrounding rocks, and the underground nuclear power station containment vessel has the functions of improving the safety and the economy of the nuclear power station. Due to the elimination of the outer layer concrete containment, different influence factors from those of a ground power station appear in the design of the containment cooling system of the underground nuclear power station. The containment spraying system realizes the spraying and cooling functions in the containment through the spray pump, and the system can be started only by the power supply under the accident condition, so that higher reliability and redundancy requirements are provided for the system, the simplification of a nuclear power plant system, particularly an underground nuclear power plant, is not facilitated, the size of the containment is limited by the size of the space of an underground cavern, and the containment spraying system is difficult to develop. The containment vessel of the underground nuclear power station is positioned in the underground cavern, and passive containment vessel cooling cannot be realized by utilizing natural convection of air, so that an air cooling mode outside the containment vessel is not feasible. The passive cooling system needs to be developed and designed according to the characteristics of the containment vessel of the underground nuclear power station.

Disclosure of Invention

The invention aims to provide a passive cooling system in a built-in cooling tower type containment of an underground nuclear power station, which realizes the passive cooling function of the containment of the underground nuclear power station.

The second purpose of the invention is to provide a cooling method of the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station.

In order to achieve the first object of the present invention, the technical solution of the present invention is: the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station is characterized in that: comprises a high-level emergency cooling water pool, a cooling water flow distribution loop, a cooling device and a cooling water recycling and heat dissipation system,

the containment is a cylindrical sealed shell, the interior of the containment is provided with a columnar through hole which is communicated up and down, and the columnar through hole and other wall surfaces of the containment form the sealed shell together so as to realize the function of sealing and containing radioactive substances; the columnar through hole is used as a part of the steel containment vessel and also used as a vertical supporting piece of a containment vessel dome to provide vertical supporting force for the underground cavern dome;

a cooling device is arranged in the columnar through hole, heat in the containment is transferred to a cooling medium in the columnar through hole through heat exchange modes such as wall surface condensation heat exchange, heat conduction and convection heat exchange, and then the heat is directly or indirectly led out by the cooling medium;

the bottom elevation of the high-level emergency cooling water pool is greater than the elevation of the cooling water flow distribution loop;

the high-level emergency cooling water pool, the cooling water flow distribution loop, the cooling device and the cooling water recycling and heat dissipation system are sequentially connected to form a closed loop.

In the technical scheme, the columnar through hole is arranged in the middle of the containment;

one or more columnar through holes are formed.

In the technical scheme, the columnar through hole is of a cylindrical structure with an upper section and a lower section which are equal in size, or of a circular truncated cone structure with a large upper section and a small lower section, so that the heat exchange area of the upper space of the containment vessel is increased.

In the technical scheme, the cooling device is selected from a containment built-in cooling tower.

In the technical scheme, the cooling device comprises a plurality of cooling pipes, and the plurality of cooling pipes are criss-cross to form a cooling pipe network; the cooling pipe network is attached to the inner wall surface of the columnar through hole;

the inlet of the cooling pipe is connected with the cooling water flow distribution loop, and the outlet of the cooling pipe is connected with the cooling water recycling heat dissipation system.

In the technical scheme, the cooling water flow distribution loop comprises a flow regulating valve and a cooling water pipe; cooling water enters a flow distribution loop after flowing out of the cooling water pool, and enters a cooling device arranged in the containment after flow distribution is carried out through a flow regulating valve and other devices; the cooling water flow is subjected to real-time feedback regulation according to the temperature and pressure distribution in the containment;

the water inlet of the cooling water pipe is connected with the water outlet of the high-level emergency cooling water pool, and the water outlet of the cooling water pipe is connected with the water inlet of the cooling pipe;

the flow regulating valve is arranged on the cooling water pipe, and the outlet end of the cooling water pipe is provided with the flow regulating valve for distributing flow;

the flow distribution loop is connected to the cooling tower arranged in the containment by at least two mutually independent cooling water pipes so as to increase the reliability of the system.

In the technical scheme, the cooling water recycling and heat dissipating system collects the cooling water flowing through a cooling pipe network of the cooling tower in the containment, cools the cooling water by the radiator and returns to the high-level emergency cooling water pool to realize the recycling of the cooling water; the cooling water recycling heat dissipation system comprises a cooling water flow control valve group, a cooling water radioactivity detection device, a circulating water pump, a radiator, a temperature detection device and the like;

the cooling water flow control valve group, the cooling water radioactivity detection device, the circulating water pump, the radiator and the temperature detection device are sequentially connected;

the cooling water flow control valve group is connected with the outlet of the cooling pipe; cooling water is collected into a cooling water recycling heat dissipation system through a cooling pipe network, and the flow of the cooling water in the cooling pipe network is adjusted through a cooling water flow control valve group at the outlet of the cooling pipe network, so that the cooling effect of the control system is matched with the required amount;

the temperature detection device is connected with an inlet of the high-level emergency cooling water pool, cooling water flowing out of the radiator can be injected into the high-level cooling water pool after the temperature detection device detects that the temperature meets the requirement; if the temperature of the cooling water is too high, the power of the radiator is increased or the flow of the cooling water entering the radiator is reduced, and the temperature of the cooling water is adjusted to meet the requirement.

In order to achieve the second object of the present invention, the technical solution of the present invention is: the cooling method of the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

when LOCA or a steam pipeline in the containment breaks, high-temperature and high-pressure steam is sprayed into the containment, and a passive cooling system in the built-in cooling tower type containment is triggered to start;

the method comprises the following steps: the low-temperature cooling water in the high-level emergency cooling water pool flows into the cooling water flow distribution loop under the action of gravity, and flows into each built-in cooling device after being subjected to flow distribution by the cooling water flow distribution loop;

step two: when cooling water flows in a cooling pipe network of the cooling device, heat in the containment is transferred to the cooling water through the heat transfer process of condensation heat exchange of the inner wall surface of the containment, heat conduction of the inner wall surface of the containment and convection heat exchange of the outer wall surface of the containment, at the moment, the heat in the containment is reduced, the temperature and the pressure are reduced, and the temperature of the cooling water in the cooling pipe network of the cooling device is increased;

step three: the heated cooling water flows out of a cooling pipe network of the cooling device and is collected to a cooling water recycling heat dissipation system, and the collected cooling water is detected for radioactivity through a cooling water radioactivity detection device;

when the radioactivity of the collected cooling water is normal, the cooling water enters a radiator for cooling after passing through a circulating water pump, and is injected into a high-level emergency cooling water pool for recirculation after being cooled;

and when the radioactivity of the collected cooling water exceeds the standard, the cooling water enters a wastewater treatment system for treatment.

The beneficial effects obtained by the invention are as follows:

1) the invention provides a passive cooling system in a built-in cooling tower type containment of an underground nuclear power station, which is characterized in that the containment is designed into a cylindrical sealed shell with an upper cylindrical through hole and a lower cylindrical through hole inside, and a cooling device is arranged in the cylindrical through hole to realize cooling of the containment, so that the cooling outside the containment of the underground nuclear power station after an outer concrete containment is removed is realized, and the integrity of a steel containment is ensured.

2) The upper and lower cylindrical through holes of the containment can be used as a part of a containment cooling system and can also be used as a vertical support piece to provide vertical supporting force for an underground cavern dome.

3) A cooling water source of a passive cooling system in a built-in cooling tower type containment of the underground nuclear power station is a high-level emergency cooling water pool, passive cooling of the containment can be still achieved under the action of gravity under the condition of a station blackout accident, system redundancy can be simplified, and reliability is improved.

4) A cooling tower type passive cooling system in a containment built in an underground nuclear power station provides a set of cooling water recycling device, cooling water after temperature rise can be cooled and recycled, and plant water of the underground nuclear power station in inland areas with relative water shortage is reduced.

The invention uses the built-in cooling tower type containment vessel, the containment vessel adopts the design of the columnar through hole which is communicated up and down, thus not only ensuring the closed containment vessel and the containment of radioactive substances, but also forming an internal cavity as a cooling space of the containment vessel, transferring the heat in the containment vessel to the cooling medium in the columnar through hole through the heat exchange modes of wall surface condensation heat exchange, heat conduction, convection heat exchange and the like, then directly or indirectly leading out the heat by the cooling medium, and safely and efficiently cooling the containment vessel of the underground nuclear power station; the columnar through hole can also be used as a longitudinal supporting structural member of the containment dome to strengthen the structural strength of the thin-wall containment; the containment vessel of the underground nuclear power station is efficiently cooled on the basis of not changing the size of the conventional containment vessel, the cooling space is abundant, the cooling process is safe, and the whole structure is stable; the problem that in the prior art, the outer side of a cavern type containment of an underground nuclear power station is tightly attached to a cavern rock wall, and a space is difficult to expand in a containment external spraying mode is solved.

Drawings

FIG. 1 is a schematic structural diagram of a passive cooling system in a built-in cooling tower type containment of an underground nuclear power station.

FIG. 2 is a top view of the containment and the position of the columnar through hole of the passive cooling system in the built-in cooling tower type containment of the underground nuclear power station.

Fig. 3 is a containment structure schematic diagram of a built-in cooling tower type passive cooling system in a containment in a single-column type underground nuclear power plant in embodiment 1 of the present invention.

Fig. 4 is a schematic structural diagram of a passive cooling system in a built-in cooling tower type containment of a four-column type underground nuclear power plant in embodiment 2 of the present invention.

Fig. 5 is a top view of the containment and the positions of the columnar through holes of the passive cooling system in the built-in cooling tower type containment of the four-column type underground nuclear power plant in embodiment 2 of the present invention.

In the figure: the system comprises a 1-high emergency cooling water pool, a 2-cooling water flow distribution loop, a 3-containment built-in cooling tower, a 4-cooling water recirculation cooling system, a 2.1-flow regulating valve, a 2.2-cooling water pipe, a 2.21-cooling water pipe I, a 2.22-cooling water pipe II, a 3-cooling device, a 3.1-cooling pipe, a 4.1-cooling water flow control valve bank, a 4.2-cooling water radioactivity detection device, a 4.3-circulating water pump, a 4.4-radiator, a 4.5-temperature detection device, a 5-containment, a 5.1-columnar through hole, a 5.2-containment inner wall surface and a 5.3-containment outer wall surface.

Detailed Description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are not intended to limit the present invention, but are merely exemplary. While the advantages of the invention will be clear and readily understood by the description.

The present invention will now be described in detail with reference to an embodiment in which the present invention is applied to cooling of containment vessels of some underground nuclear power plants, and the present invention also has a guiding effect in cooling containment vessels of other underground nuclear power plants.

Example 1:

in the embodiment, the containment vessel of the underground nuclear power station adopts a built-in cooling tower type passive cooling system in the containment vessel of the single-column underground nuclear power station, namely, one columnar through hole 5.1 is arranged.

As shown in fig. 1, the passive cooling system in the built-in cooling tower type containment of the single-column underground nuclear power plant of the embodiment includes a high-level emergency cooling water pool 1, a cooling water flow distribution loop 2, a built-in containment cooling tower, and a cooling water recirculation heat dissipation system 4.

The elevation of the bottom of the high-level emergency cooling water pool 1 is larger than the elevation of the cooling water flow distribution loop 2, and the water filling amount of the water pool is at least larger than the water consumption of the cooling system for 72 hours under the condition of 100% flow opening.

The inlet of the cooling water flow distribution loop 2 is connected with the water outlet 1.1 of the high-level emergency cooling water pool, cooling water enters the flow distribution loop after exiting the cooling water pool, and enters the cooling tower arranged in the containment after being subjected to flow distribution through devices such as a flow regulating valve 2.1 and the like; the cooling water flow is subjected to real-time feedback regulation according to the temperature and pressure distribution in the containment; the cooling water flow distribution loop 2 is connected to the containment built-in cooling tower through at least two mutually independent cooling water pipes 2.2 (in the embodiment, the two mutually independent cooling water pipes 2.2 are a cooling water pipe i 2.21 and a cooling water pipe ii 2.22 respectively) so as to increase the reliability of the system.

The containment built-in cooling tower is a cooling device arranged in a columnar through hole 3.1 in the middle of the containment, the cooling device is a cooling pipe network attached to the inner wall surface of the columnar through hole, the cooling pipe network is composed of cooling pipes 3.1 which are criss-cross, and the inlet of each cooling pipe 3.1 is connected with the outlet of the cooling water flow distribution loop 2. The columnar through hole 5.1 and other wall surfaces of the containment form a sealed shell together so as to realize the function of sealing and containing radioactive substances; the columnar through hole 5.1 is in a cylindrical shape with the upper and lower sections being equal in size.

The cooling water recycling and heat dissipating system 4 collects the cooling water flowing through the cooling pipe network of the cooling tower in the containment, cools the cooling water by the radiator 4.4 and then returns to the high-level emergency cooling water pool, so that the cooling water can be recycled. The cooling water recycling heat dissipation system comprises a cooling water flow control valve group 4.1, a cooling water radioactivity detection device 4.2, a circulating water pump 4.3, a radiator 4.4, a temperature detection device 4.5 and the like.

The operation flow of the passive cooling system in the built-in cooling tower type containment of the single-column underground nuclear power station in the embodiment is as follows:

when LOCA or a steam pipeline in the containment breaks, high-temperature and high-pressure steam is sprayed into the containment, and a passive cooling system in the built-in cooling tower type containment is triggered to start;

the method comprises the following steps: the low-temperature cooling water in the high-level emergency cooling water pool 1 flows into the flow distribution loop 2 under the action of gravity, and flows into the built-in cooling tower after flow distribution;

step two: when cooling water flows in a cooling pipe network, heat in the containment is transferred to the cooling water through the heat transfer process of condensation heat exchange of the inner wall surface of the containment, heat conduction of the wall surface of the containment and convection heat exchange of the outer wall surface of the containment, and at the moment, the heat in the containment is reduced, the temperature and the pressure are reduced, and the temperature of the cooling water is increased;

step three: the heated cooling water flows out of the cooling pipe network and is collected to the cooling water recycling heat dissipation system 4; the activity of the collected cooling water is detected by a radioactivity detection device 4.2, if the activity is normal, the cooling water enters a radiator 4.4 for cooling through a circulating water pump 4.3, and is injected into a high-level cooling water pool 1 for recirculation after being cooled; and if the radioactivity exceeds the standard, the wastewater enters a wastewater treatment system for treatment.

The flow of cooling water in the cooling pipe network 3.3 can be adjusted by adjusting the flow adjusting valve 3.4 at the outlet of the cooling pipe network 3.3, so that the cooling effect of the control system is matched with the required quantity.

In the embodiment, the cooling water flowing out of the radiator 4.4 can be injected into the high-level cooling water pool 1 after the temperature of the cooling water is detected by the temperature measuring device 4.5 to meet the requirement; if the temperature is too high, the power of the radiator needs to be increased or the flow of cooling water entering the radiator needs to be reduced.

As shown in fig. 2, the upper and lower through holes (i.e. the columnar through holes 5.1) of the passive cooling system in the built-in cooling tower type containment of the single-column type underground nuclear power plant of the embodiment are located in the middle of the containment 5.

Fig. 3 shows a containment structure of the passive cooling system in the built-in cooling tower type containment of the single-column underground nuclear power station.

The foregoing shows and describes the general principles and principal structural features of the present invention. The present invention is not limited to the above examples, and various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the claimed invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Example 2:

as shown in fig. 4: the structure and operation flow of this embodiment are basically the same as those of embodiment 1, except that: in the embodiment, the containment vessel of the underground nuclear power station adopts a multi-column type passive cooling system arranged in a cooling tower type containment vessel and arranged in the underground nuclear power station, namely, a plurality of columnar through holes 5.1 are arranged.

In the embodiment, a steel containment of a passive cooling system in a built-in cooling tower type containment of a multi-column underground nuclear power station is provided with a plurality of upper and lower through holes (namely, columnar through holes 5.1), and each upper and lower through hole (namely, columnar through hole 5.1) can be provided with a cooling device 3.

Fig. 5 shows the positions of the upper and lower through holes of the passive cooling system containment in the built-in cooling tower type containment of the multi-column underground nuclear power plant of the embodiment.

Other parts not described belong to the prior art.