Small integrated pressurized water reactor double water-water forced circulation heat supply system

Abstract

The present application belongs to the technical field of nuclear engineering, and particularly relates to a small-sized integrated pressurized water reactor double water-water forced circulation heat supply system. The system comprises a primary loop, a secondary loop and a tertiary loop. The primary loop is used for direct heat exchange with a reactor core heat source. The secondary loop is an independent closed intermediate circulation loop, which plays an isolating role for the primary loop and the tertiary loop, and transmits the heat generation of the primary loop reactor core to the tertiary loop. The present application has the beneficial effects of: having a higher efficiency energy conversion system, water-water heat transfer produces less waste heat than steam-water condensation, and the heat transfer efficiency is higher. Having a more concise energy conversion system, the system adopts a water-water forced circulation system design concept, without steam extraction, condensation, reheating, pressurization, circulation deoxygenation and other complex facilities, the system is more stable, has a smaller floor area, and is more compact in design.

Description

Technical Field

[0001] This invention belongs to the field of nuclear engineering technology, specifically relating to a small integrated pressurized water reactor dual-water forced circulation heating system. Background Technology

[0002] The ACP100 demonstration project, "Linglong One," is the world's first commercially available modular small pressurized water reactor. It adopts an integrated reactor design and a passive safety system. Through design improvements, its core failure frequency (CDF) is less than 10. -6 The probability of a large release of radioactive material per year is less than 10. -7 The nuclear power plant has achieved the safety level of third-generation nuclear energy systems, and can meet the diverse needs of densely populated areas and inland and coastal regions for nuclear cogeneration, hydropower, etc. It can also be used for seawater desalination, island energy supply, nuclear merchant ships, etc.

[0003] The existing integrated pressurized water reactor uses a water-to-water primary loop and a steam-to-water secondary loop. Its energy conversion system is complex and has an efficiency of about 38%, resulting in most of the heat being emitted as waste heat, which is not conducive to improving the economic efficiency of integrated small reactor applications. On the other hand, to achieve heat conversion in the secondary loop of the existing integrated pressurized water reactor, it is necessary to carry out complex processes such as steam extraction, condensation, reheating, pressurization, and deoxygenation, resulting in a large number of equipment, a larger footprint, and complex operation. Summary of the Invention

[0004] The purpose of this invention is to provide a small integrated pressurized water reactor dual water-to-water forced circulation heating system. Both the primary and secondary loops use water-to-water forced circulation for heat transfer, and the system exchanges heat with the user-side third loop for the final heat exchange. This significantly improves economic efficiency and achieves safe, efficient, and stable heating.

[0005] The technical solution of the present invention is as follows: a small integrated pressurized water reactor dual water-to-water forced circulation heating system, including a primary loop, a secondary loop and a tertiary loop, wherein the primary loop is used for direct heat exchange with the reactor core heat source, the secondary loop is an independent closed intermediate circulation loop, which isolates the primary loop and the tertiary loop, and transfers the heat generated by the reactor core in the primary loop to the tertiary loop.

[0006] The primary loop includes a primary loop outlet connector, a main pump, a primary loop built-in heat exchanger, and two outlets of the pressure vessel are each connected to a primary loop outlet connector. The two primary loop outlet connectors are each connected to the primary loop built-in heat exchanger via pipelines. The primary loop built-in heat exchanger is connected to the main pump via pipelines. The main pump is connected to the pressure vessel.

[0007] The main pump is directly mounted on the pressure vessel.

[0008] The primary heat exchanger is built into the pressure vessel.

[0009] The secondary loop includes a secondary loop inlet pipe, a nitrogen pressure stabilizing device, a pressure stabilizing tank, a secondary loop circulating water pump, a secondary heat exchanger, a secondary loop outlet pipe, and a nitrogen supply device. The two secondary loop inlet pipes are respectively connected to the outlet pipe of a primary loop built-in heat exchanger. The secondary loop inlet pipes are connected to the secondary loop circulating water pump. The secondary loop circulating water pump is connected to the secondary heat exchanger through a pipeline. The secondary heat exchanger is connected to the inlet pipe of a primary loop built-in heat exchanger through a pipeline. The pressure stabilizing tank is connected to the pipeline between the secondary loop circulating water pump and the secondary heat exchanger through a pipeline. The pressure stabilizing tank is connected to the nitrogen pressure stabilizing device through a pipeline. The nitrogen pressure stabilizing device is connected to the nitrogen supply device through a pipeline.

[0010] The nitrogen pressure stabilizing device is a steel container filled with nitrogen. During normal operation, the nitrogen pressure stabilizing device automatically adjusts the nitrogen pressure to control the pressure inside the pressure stabilizing water tank.

[0011] The three-loop system includes a heating network water supply pipe and a three-loop return water pipe. The two outlet pipes of the two secondary heat exchangers in the second loop are connected through the heating network water supply pipe. One outlet pipe is led out from the heating network water supply pipe. The inlet pipes of the two secondary heat exchangers are connected through the three-loop return water pipe. The three-loop return water pipe is connected to the return water pipe through a pipeline.

[0012] The beneficial effects of this invention are as follows: Traditional secondary loops use a steam-water cycle, while this invention uses a subcooled water cycle. Compared to steam-water condensation, the secondary loop water-water cycle system generates less waste heat and has higher heat transfer efficiency. The tertiary loop user side achieves final heat exchange through the circulating water system and the higher-temperature subcooled water from the secondary loop to meet the user's heating needs. 1. It has a more efficient energy conversion system; water-water heat transfer generates less waste heat and has higher heat transfer efficiency compared to steam-water condensation. 2. It has a simpler energy conversion system, employing a forced water-water circulation system design concept, eliminating complex facilities such as steam extraction, condensation, reheating, pressurization, and deoxygenation circulation. The system is more stable, occupies less space, and has a more compact design. 3. The three-loop design, and the slightly positive pressure design of the secondary loop compared to the primary loop, fundamentally eliminate the risk of radioactive release from the primary loop to the tertiary loop user side, ensuring high safety. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a small integrated pressurized water reactor dual-water forced circulation heating system provided by the present invention.

[0014] In the diagram: 1. Primary loop outlet pipe; 2. Primary loop circulating water pump; 3. Primary loop built-in heat exchanger; 4. Secondary loop inlet pipe; 5. Nitrogen pressure stabilizing device, with its outlet connected to the pressure stabilizing water tank and its top connected to the nitrogen supply system; 6. Pressure stabilizing water tank; 7. Secondary loop circulating water pump; 8. Secondary heat exchanger; 9. Secondary loop outlet pipe; 10. Heating network water supply pipe; 11. Tertiary loop return pipe; 12. Pressure vessel; 13. Nitrogen supply device. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] To address the problems existing in the prior art, this invention proposes to modify the secondary loop into a water-to-water circulation system, realizing a small integrated pressurized water reactor dual-water-to-water forced circulation heating system. Simultaneously, by maintaining a slightly positive pressure in the secondary loop compared to the primary loop, the risk of radioactive release from the primary loop to the tertiary loop user side is fundamentally eliminated, significantly improving the safety and economy of the comprehensive utilization of the small pressurized water reactor.

[0017] like Figure 1 As shown, a small integrated pressurized water reactor dual-water forced circulation heating system includes a primary loop, a secondary loop, and a tertiary loop. The primary loop is used for direct heat exchange with the reactor core heat source, while the secondary loop is an independent closed intermediate circulation loop that isolates the primary and tertiary loops and transfers the heat generated by the reactor core in the primary loop to the tertiary loop.

[0018] The primary loop includes a primary loop outlet nozzle 1, a main pump 2, a primary loop built-in heat exchanger 3, and two outlets of the pressure vessel 12 are respectively connected to a primary loop outlet nozzle 1. The two primary loop outlet nozzles 1 are respectively connected to the primary loop built-in heat exchanger 3 through pipelines. The primary loop built-in heat exchanger 3 is connected to the main pump 2 through pipelines. The main pump 2 is connected to the pressure vessel 12.

[0019] The main pump 2 of the primary circuit is directly installed on the pressure vessel, eliminating the main pipeline and greatly reducing the probability of water loss in the primary circuit. At the same time, the heat exchanger of the primary circuit is built into the pressure vessel. This method makes the integrated heating system simpler, does not occupy more space, is more compact in structure, and can further reduce the size of the integrated heating system.

[0020] After passing through the containment tube and the descending section, the coolant enters the reactor core from bottom to top. After being heated by the reactor core, it enters the heat exchanger built into the primary loop along the ascending section, where it transfers heat to the secondary loop subcooled water. After the coolant flows through the heat exchanger and transfers heat, its temperature decreases, and it returns to the pressure vessel via the main pump, completing the primary loop cycle.

[0021] The secondary loop includes a secondary loop inlet pipe 4, a nitrogen pressure stabilizing device 5, a pressure stabilizing water tank 6, a secondary loop circulating water pump 7, a secondary heat exchanger 8, a secondary loop outlet pipe 9, and a nitrogen supply device 13. The two secondary loop inlet pipes 4 are respectively connected to the outlet pipe of a primary loop built-in heat exchanger 3. The secondary loop inlet pipes 4 are connected to the secondary loop circulating water pump 7. The secondary loop circulating water pump 7 is connected to the secondary heat exchanger 8 through a pipeline. The secondary heat exchanger 8 is connected to the inlet pipe of a primary loop built-in heat exchanger 3 through a pipeline. The pressure stabilizing water tank 6 is connected to the secondary loop circulating water pump 7 and the secondary heat exchanger 8 through a pipeline. The pressure stabilizing water tank 6 is connected to the nitrogen pressure stabilizing device 5 through a pipeline. The nitrogen pressure stabilizing device 5 is connected to the nitrogen supply device 13 through a pipeline.

[0022] The heat generated by the reactor core inside the pressure vessel 12 is transferred to the secondary loop subcooled water through the primary loop built-in heat exchanger 3. After absorbing the heat, the subcooled water is circulated through the secondary loop circulating water pump 7 and enters the secondary loop secondary heat exchanger 8 to transfer the heat to the tertiary loop. The water in the secondary loop pipes flows through the secondary heat exchanger 8 to transfer heat and its temperature decreases. It then returns to the primary loop built-in heat exchanger 3 through the secondary loop circulating water pump 7 to absorb heat again, completing the secondary loop circulation.

[0023] The secondary loop is equipped with a pressure stabilizing tank 6, and a nitrogen pressure stabilizing device 5 is installed on the top of the pressure stabilizing tank 6, so that the pressure stabilizing tank has the functions of controlling pressure and buffering water level, so that the pressure of the secondary loop is always slightly higher than that of the primary loop, and prevents the subcooled water in the secondary loop from vaporizing.

[0024] The nitrogen pressure stabilizing device 5 is a steel container filled with nitrogen. During normal operation, the nitrogen pressure stabilizing device will automatically adjust the opening of the nitrogen pressure regulating valve according to the pressure gauge in the pressure stabilizing water tank to control the pressure in the pressure stabilizing water tank.

[0025] The three-loop system includes a heating network water supply pipe 10 and a three-loop return water pipe 11. The outlet pipes of the two secondary heat exchangers 8 in the second loop are connected through the heating network water supply pipe 10. The heating network water supply pipe 10 leads out an outlet pipe. The inlet pipes of the two secondary heat exchangers 8 are connected through the three-loop return water pipe 11. The three-loop return water pipe 11 is connected to the return water pipe through a pipeline.

[0026] The three-loop circulating water flows in from the water supply pipe, passes through the secondary heat exchanger to remove the heat from the secondary loop, and finally flows into the user's heating network for heating.

[0027] This application proposes a dual water-to-water forced circulation heating system for modular integrated small pressurized water reactors. This system transfers heat generated by the reactor core reaction to the tertiary loop (heating network) via the primary and secondary loops, preventing radioactive water leakage into the heating network and thus ensuring safety while providing reactor heating. Furthermore, the secondary loop employs a water-to-water forced circulation system design, eliminating the need for complex facilities such as steam extraction, condensation, reheating, pressurization, and deoxygenation circulation, resulting in a more compact design and a smaller footprint.

[0028] The working process of this invention is as follows: Under normal reactor operation, the coolant enters the reactor core from bottom to top after passing through the containment tube and the descending section. After being heated by the reactor core, it enters the built-in heat exchanger 3 through the primary loop outlet water inlet 1, transferring the heat to the secondary loop subcooled water. After the coolant flows through the heat exchanger and transfers heat, its temperature decreases. It then returns to the pressure vessel through the primary loop circulating water pump 2, completing the primary loop cycle.

[0029] The secondary loop is equipped with a nitrogen pressure stabilizing device 5. The top inlet of the device is connected to the nitrogen supply device, and the outlet is connected to the pressure stabilizing water tank 6. The secondary loop subcooled water supplied by the pressure stabilizing water tank 6 enters the primary built-in heat exchanger 3 through the secondary loop inlet pipe 4. After absorbing heat from the coolant, the temperature rises. After flowing through the secondary loop outlet pipe 9, it enters the secondary heat exchanger 8, where it transfers heat to the tertiary loop water and its temperature drops. Then, it returns to the primary heat exchanger through the circulating water pump 7 to absorb heat again, completing the cycle.

[0030] The three-loop circulating water flows in from the heating network supply pipe 11, passes through the secondary heat exchanger 8 to remove the heat from the second loop, and finally flows into the user's heating network for heating.

[0031] In the primary loop, the coolant, being in contact with the reactor core, may be radioactive. If it directly exchanges heat with the heating network water, leaks or other issues could cause it to enter the heating network water, endangering users' health. By exchanging heat between the primary and secondary loops, the heating network water is effectively separated from the coolant flowing through the reactor core, significantly improving heating safety. Furthermore, the secondary loop is equipped with a pressure stabilizing device to control the pressure inside the pressurized water tank, ensuring that the secondary loop pressure is always higher than the primary loop pressure, thus preventing radioactive water from leaking into the user-side loops.

Claims

1. A small integrated pressurized water reactor dual-water-forced circulation heating system, characterized in that: It includes a primary loop, a secondary loop, and a tertiary loop. The primary loop is used for direct heat exchange with the core heat source. The secondary loop is an independent, closed intermediate loop that isolates the primary and tertiary loops and transfers the heat generated by the primary loop core to the tertiary loop.

2. The small integrated pressurized water reactor dual water-to-water forced circulation heating system as described in claim 1, characterized in that: The primary loop includes a primary loop outlet connector, a main pump, a primary loop built-in heat exchanger, and two outlets of the pressure vessel are each connected to a primary loop outlet connector. The two primary loop outlet connectors are each connected to the primary loop built-in heat exchanger via pipelines. The primary loop built-in heat exchanger is connected to the main pump via pipelines. The main pump is connected to the pressure vessel.

3. The small integrated pressurized water reactor dual water-to-water forced circulation heating system as described in claim 2, characterized in that: The main pump is directly mounted on the pressure vessel.

4. The small integrated pressurized water reactor dual-water forced circulation heating system as described in claim 2, characterized in that: The primary heat exchanger is built into the pressure vessel.

5. The small integrated pressurized water reactor dual water-to-water forced circulation heating system as described in claim 1, characterized in that: The secondary loop includes a secondary loop inlet pipe, a nitrogen pressure stabilizing device, a pressure stabilizing tank, a secondary loop circulating water pump, a secondary heat exchanger, a secondary loop outlet pipe, and a nitrogen supply device. The two secondary loop inlet pipes are respectively connected to the outlet pipe of a primary loop built-in heat exchanger. The secondary loop inlet pipes are connected to the secondary loop circulating water pump. The secondary loop circulating water pump is connected to the secondary heat exchanger through a pipeline. The secondary heat exchanger is connected to the inlet pipe of a primary loop built-in heat exchanger through a pipeline. The pressure stabilizing tank is connected to the pipeline between the secondary loop circulating water pump and the secondary heat exchanger through a pipeline. The pressure stabilizing tank is connected to the nitrogen pressure stabilizing device through a pipeline. The nitrogen pressure stabilizing device is connected to the nitrogen supply device through a pipeline.

6. The small integrated pressurized water reactor dual water-to-water forced circulation heating system as described in claim 5, characterized in that: The nitrogen pressure stabilizing device is a steel container filled with nitrogen. During normal operation, the nitrogen pressure stabilizing device automatically adjusts the nitrogen pressure to control the pressure inside the pressure stabilizing water tank.

7. The small integrated pressurized water reactor dual water-to-water forced circulation heating system as described in claim 1, characterized in that: The three-loop system includes a heating network water supply pipe and a three-loop return water pipe. The two outlet pipes of the two secondary heat exchangers in the second loop are connected through the heating network water supply pipe. One outlet pipe is led out from the heating network water supply pipe. The inlet pipes of the two secondary heat exchangers are connected through the three-loop return water pipe. The three-loop return water pipe is connected to the return water pipe through a pipeline.

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