CN202887745U - Active and passive combined safety shell heat extraction device - Google Patents

Abstract

The utility model belongs to the technique of reactor design, and in particular relates to an active and passive combined safety shell heat extraction device which structurally comprises a safety shell spraying system and a passive safety shell heat deriving system; one end of a pipeline of the safety shell spraying system is connected with a material exchange water tank, and the other end of the pipeline of the safety shell spraying system is connected to a spraying connecting pipe on the top of a safety shell through a spraying pump and a heat exchanger; the passive safety shell heat deriving system comprises a heat exchanger or a heat exchanger group which is arranged in the safety shell; the heat exchanger or the heat exchanger group is connected with a heat exchange water tank arranged out of the safety shell through a rising pipeline and a falling pipeline; and the height of the heat exchange water tank is higher than the height of the heat exchanger or the heat exchanger group. The active and passive combined safety shell heat extraction device provided by the utility model can be used for improving the dependence on a safety-level power supply by a traditional active safety system nuclear power station, and improving the intrinsic safety of the nuclear power station safety shell heat extraction system.

Description

A Containment Heat Removal Device Combining Active and Passive

technical field

The utility model belongs to the reactor design technology, in particular to a containment heat exhaust device combining active and passive.

Background technique

The containment heat removal system of traditional nuclear power plants uses the containment spray system to remove the heat and radioactive substances entering the containment, so as to control the environmental conditions of the containment. The purpose of setting up the containment sprinkler system is to spray cold water from the upper part of the containment at an appropriate time to cool the atmosphere of the containment and limit the peak pressure of the containment after LOCA or MSLB. In addition, if necessary, chemical agents are added to the spray liquid to remove suspended iodine and iodine vapor in the containment atmosphere. The active containment spray system has the characteristics of strong cooling capacity and good heat removal effect after accidents, and has been widely used. However, this technology relies too much on the AC power supply, and it cannot achieve long-term effective heat removal of the containment after a power outage superimposed on the whole plant and a LOCA or MSLB accident.

The representative of the passive containment heat removal device is the passive containment cooling system of AP1000 in the United States. The passive containment cooling system uses a passive method to dissipate the heat in the containment to the final heat sink - the atmosphere, as shown in Figure 1. Under normal operating conditions, the air enters from the top inlet 1 of the shielding structure, flows through the descending channel and then reversely passes through the ascending channel, taking away the heat transferred by the container wall of the steel containment vessel, and finally exhausts from the chimney to the environment, above the containment vessel Set up Gravity Fill Tank 2. After receiving the high pressure signal of the containment, the post-accident operation of the system will start automatically, and only need to open any one of the three normally closed isolation valves, and the system can be started without other actions. The start of the system can also be started manually by the operator in the main control room or remote shutdown workstation.

Since a single containment spray system relies too much on safety-level power sources, it is a general trend to improve the safety level of nuclear power plants to control the environmental conditions of containment by combining active and passive methods. Passive containment heat removal devices do not rely on traditional power sources, but rely on natural circulation to complete post-accident safety functions. In the event of a plant-wide power outage or an accident related to the failure of the containment sprinkler system, the system can still operate and achieve the integrity of the containment, which is an effective supplement to the active containment heat removal device.

Utility model content

The purpose of the utility model is to aim at the defect of the containment heat exhaust system of the traditional nuclear power plant, provide a containment heat exhaust device combining active and passive, improve the dependence of the traditional active safety system nuclear power plant on the safety level power supply, and improve the safety of the nuclear power plant containment Inherent safety of the heat removal system.

The technical scheme of the utility model is as follows: a containment heat removal device combining active and passive, including a containment spray system and a passive containment heat export system, one end of the pipeline of the containment spray system is connected to The refueling water tank, the other end is connected to the spray header on the top of the containment after passing through the spray pump and heat exchanger; the passive containment heat export system includes a heat exchanger or a heat exchanger installed inside the containment The heat exchanger or the heat exchanger group is connected to the heat exchange tank arranged outside the containment through the ascending pipeline and the descending pipeline, and the height of the heat exchange tank is higher than that of the heat exchanger or the heat exchanger group.

Further, the active and passive combined containment heat removal device described above, wherein a chemical additive tank is connected to the upstream pipeline of the spray pump of the containment spray system.

Further, the active and passive combined containment heat removal device described above, wherein the spray headers of the containment spray system are arranged at different elevations on the top of the containment.

Further, the active and passive combined containment heat removal device described above, wherein the refueling water tank connected to the pipeline of the containment spray system is arranged at the pit below the core inside the containment, The spray pump, heat exchanger and chemical additive tank are arranged outside the containment vessel.

Furthermore, the active and passive combined containment heat removal device as described above, wherein a steam-water separator is provided in the heat exchange tank outside the containment, and the heat removal system of the passive containment The riser line of the heat exchanger or heat exchanger group is connected with the steam separator.

Further, the active and passive combined containment heat removal device described above, wherein isolation valves are respectively provided on the rising pipeline and the descending pipeline of the passive containment heat export system.

Further, the active and passive combined containment heat removal device as described above, wherein the heat exchange tank is a closed reinforced concrete structure with a stainless steel lining.

The beneficial effects of the utility model are as follows: the containment heat removal device provided by the utility model can not only cope with the design basis accidents through the combination of active and passive methods, but also be able to deal with accidents beyond the design basis and serious accidents such as power outages in the whole plant. Or the active containment heat removal device fails or fails to continuously discharge the heat in the containment, which improves the inherent safety of the system, improves the dependence of traditional active safety system nuclear power plants on safety-level power supplies, and improves the safety of nuclear power plants , and at the same time, the integrity of the containment can be effectively maintained.

Description of drawings

Figure 1 is a schematic structural diagram of the passive containment cooling system of AP1000;

Fig. 2 is a schematic structural diagram of a containment heat removal device combining active and passive components.

Detailed ways

The containment heat removal device provided by the utility model combines an active containment spray system with a passive containment heat export system. One end of the pipeline of the containment spray system is connected to the refueling water tank, and the other end is connected to the spray header on the top of the containment after passing through the spray pump and heat exchanger; A heat exchanger or a heat exchanger group, the heat exchanger or a heat exchanger group is connected to a heat exchange tank arranged outside the containment through an ascending pipeline and a descending pipeline.

The active containment sprinkler system (CSP system for short) is used to remove heat from the containment under design basis accident conditions. Under accident conditions (LOCA or rupture of steam pipes in containment), when the pressure and temperature When raised to a certain value, the pressure and temperature of the containment vessel are reduced to an acceptable level to maintain the integrity of the containment vessel. The passive containment heat extraction system (referred to as PCS system) is used for long-term heat removal of the containment under accident conditions beyond the design basis, including accidents related to plant power outage and sprinkler system failure. The PCS system is also used for accident mitigation in severe accident conditions (if the beyond-design basis accident develops into a severe accident in which the core deteriorates significantly). When a beyond design basis accident (including a severe accident) occurs in a nuclear power plant, the pressure and temperature of the containment vessel are reduced to an acceptable level to maintain the integrity of the containment vessel. Both the containment sprinkler system and the containment heat export system are used for containment heat removal after an accident, so the two systems are combined to control the temperature and pressure level in the containment to maintain the integrity of the containment, which can deal with design basis accidents to Beyond design basis accidents to serious accidents. This combination scheme covers a wider range of accident conditions than a single active system or a passive system, and the two systems are put into operation after the accident to limit the environmental conditions of the containment better.

Below in conjunction with accompanying drawing and embodiment the utility model is described in detail.

As shown in Figure 2, the active and passive containment heat removal device includes a containment spray system (CSP system) and a passive containment heat export system (PCS system), the containment spray system One end of the pipeline is connected to the refueling water tank 2, and the other end is connected to the spray header 9 on the top of the containment after passing through the spray pump 3 and the heat exchanger 4. According to the structural characteristics of the containment dome, the spray header 9 is located on the top of the containment At different elevations, the upstream pipeline of the spray pump 3 is connected with a chemical additive box 5, the chemical additive box is used to add NaOH, and the effect is to absorb volatile iodine in the air; and improve the pH value of the spray water to avoid Corrosion of materials of construction. The refueling water tank 2 can be arranged outside the containment or inside the containment. In a preferred solution, the refueling water tank 2 is arranged in the pit below the core in the containment, and the refueling water tank is located at the lowest point, so as to facilitate the collection of spray water from the containment. , The water source brought by the pipe breach. The spray pump 3, the heat exchanger 4 and the chemical additive tank 5 are all arranged outside the containment.

The active containment heat removal device is the CSP system. The CSP system pumps the spray water from the built-in or external refueling water tank to the spray pipeline through the spray pump (electric pump), and sprays cooling water into the containment to continuously lower the containment. Internal heating and boosting due to accidents.

The passive containment heat removal system (PCS system) includes a heat exchanger or heat exchanger group 6 arranged inside the containment vessel 1, and the heat exchanger or heat exchanger group 6 passes through the ascending pipeline and the descending pipeline It is connected with the heat exchange tank 7 arranged outside the containment, and the height of the heat exchange tank 7 is higher than that of the heat exchanger or the heat exchanger group 6 . The water exchange tank 7 is provided with a steam-water separator 8, and the ascending pipeline of the heat exchanger or the heat exchanger group 6 is connected to the steam-water separator 8, and the ascending pipeline and the descending pipeline of the passive containment heat export system are respectively Isolation valves 10, 11 are provided.

The PCS system adopts the passive design concept, and uses the heat exchanger or heat exchanger group arranged in the containment to conduct condensation, convection and radiation heat transfer with the high-temperature air in the containment, and the cooling water of the heat exchanger in the hot section absorbs heat in the containment The heat of the high-temperature air heats up, the density decreases, and forms a density difference with the water in the cold pipe section. It enters the steam-water separator in the heat exchange tank through the ascending pipeline, and after being cooled by the heat exchange tank, it flows back to the heat exchanger through the descending pipeline to complete the natural circulation. . The final heat sink of the heat exchange tank installed outside the containment is the atmosphere. Through the flow of water in the heat exchanger tube, the heat in the containment is continuously brought to the outside of the containment, so as to realize accidents beyond design basis and serious accidents. continuous passive containment heat removal.

In this embodiment, the PCS system is set up in three columns, and each series includes a set of heat exchangers, a steam-water separator, a water exchange tank, an electric isolation valve, and two parallel pneumatic valves (located in the descending pipeline). The heat exchanger is arranged on the circumference of the containment vessel; the heat exchange tank is a stainless-steel-lined equipment with a reinforced concrete structure and is arranged in the ring-shaped building of the double-layer containment vessel shell.

After the containment pressure reaches the threshold in a design basis accident, the CSP system is automatically triggered or manually opened by the operator to discharge the heat in the containment. The PCS system adopts passive technology. In the event of a plant-wide power outage, the system is automatically put into operation without operator intervention, and the long-term heat removal of the containment is achieved by using natural circulation. In the case of no operator operation, the passive heat removal time of the containment vessel shall be maintained for at least 72 hours, and other means of replenishing water may be considered after 72 hours.

The utility model adopts a combination of active and passive ways to export the heat in the containment, can maintain the integrity of the containment, and meets the requirement of maintaining the integrity of the containment in the nuclear safety regulations HAF102 (2004) "Nuclear Power Plant Design Safety Regulations" and containment heat removal requirements.

Obviously, those skilled in the art can make various changes and modifications to the utility model without departing from the spirit and scope of the utility model. In this way, if these modifications and variations of the present utility model fall within the scope of the claims of the utility model and equivalent technologies, the utility model is also intended to include these modifications and variations.

Claims (7)

1. A combination of active and passive containment heat removal device, characterized in that it includes a containment spray system and a passive containment heat export system, and one end of the pipeline of the containment spray system is connected to refueling The water tank (2), the other end is connected to the spray header (9) on the top of the containment after passing through the spray pump (3) and the heat exchanger (4); the passive containment heat export system includes The heat exchanger or heat exchanger group (6) inside the shell (1), the heat exchanger or heat exchanger group (6) is connected with the heat exchange tank (7) outside the containment through the ascending pipeline and the descending pipeline ), the height of the heat exchange tank (7) is higher than the height of the heat exchanger or heat exchanger group (6). 2. The combined active and passive containment heat removal device according to claim 1, characterized in that: a chemical additive tank is connected to the upstream pipeline of the spray pump (3) of the containment spray system (5). 3. The combined active and passive containment heat removal device according to claim 1 or 2, characterized in that: the spray header (9) of the containment spray system is arranged in the containment (1 ) at different elevations at the top. 4. The combined active and passive containment heat removal device according to claim 3, characterized in that: the refueling water tank (2) connected to the pipeline of the containment spray system is arranged in the containment At the position of the pit below the inner core, the spray pump (3), heat exchanger (4) and chemical additive tank (5) are arranged outside the containment vessel. 5. The combined active and passive containment heat removal device according to claim 1, characterized in that: a steam-water separator (8) is provided in the heat exchange tank (7) outside the containment, The rising pipeline of the heat exchanger or heat exchanger group (6) of the passive containment heat export system is connected with the steam-water separator (8). the 6. The combined active and passive containment heat removal device according to claim 1 or 5, characterized in that: the rising pipeline and the descending pipeline of the passive containment heat export system are respectively provided with isolation Valves (10, 11). 7. The combined active and passive containment heat removal device according to claim 6, characterized in that: the heat exchange tank (7) is a closed reinforced concrete structure with a stainless steel lining. the

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