High-temperature gas-cooled reactor nuclear power plant high-pressure heater disassembly transient compensation system and working method thereof

Abstract

The application discloses a high-temperature gas cooled reactor nuclear power plant high-pressure heater disassembly transient compensation system and a working method thereof, and belongs to the technical field of nuclear power. When the unit is normally operated, part of steam is extracted from main steam to heat low-temperature molten salt, and heat is transferred to high-temperature molten salt and stored in a high-temperature molten salt storage tank; when a high-pressure heater disassembly transient condition occurs, the system automatically switches feed water to a second heat exchanger, transports high-temperature molten salt in the storage tank to the second heat exchanger to heat feed water, and returns low-temperature molten salt after heat exchange and cooling to the low-temperature molten salt storage tank for storage. Through the system, the feed water temperature at the steam generator inlet can be stabilized, the cold and hot helium temperatures of the primary loop are further stabilized, reactor accidents caused by severe condition fluctuations are prevented, the risk resistance of the unit is improved, the unit can be stably operated and power generation is maintained, and the system has high safety and economy.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to a transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater decoupling and its working method. Background Technology

[0002] High-temperature gas-cooled reactors (HTGRs), as passive advanced reactors exhibiting fourth-generation characteristics, have garnered significant attention due to their inherent safety features. HTGRs use helium as the primary working medium and water as the secondary working medium. Helium absorbs heat in the reactor core and then transfers it to the water in the secondary loop via a steam generator to produce steam for the turbine. To ensure reactor safety, the temperatures of the cold and hot helium entering and exiting the reactor are strictly controlled; exceeding these temperature ranges will directly trigger reactor shutdown protection. Simultaneously, the feedwater temperature to the steam generator, which is highly coupled to the helium temperature, is also strictly controlled to prevent disturbances to the cold and hot helium temperatures.

[0003] During normal operation, to improve energy efficiency and optimize the working state of the steam generator, the high-pressure feedwater, after being pressurized by the feedwater pump, is first heated to 200-250°C by the high-pressure heater before entering the steam generator for heat exchange. The steam source for the heater is drawn from the high-pressure cylinder of the steam turbine. As an important device directly connected to the steam turbine body, the high-pressure heater is equipped with a water level monitoring device and corresponding thermal protection logic to prevent steam backflow or backflow of water from the heater to the steam turbine in case of an accident.

[0004] When the liquid level rises to the alarm setting or the turbine trips, the interlock closes the steam inlet valve of the high-pressure heater, simultaneously switching the feedwater to bypass operation and disconnecting the high-pressure heater from the system. After the high-pressure heater is disconnected, the feedwater loses its heating source, causing a sharp drop in the feedwater temperature at the steam generator inlet. This not only poses a risk of metal stress to the steam heater operation but also, due to untimely adjustments in the primary loop, leads to excessive temperature variations in the hot and cold helium, triggering reactor protection mechanisms and causing a shutdown. This process not only risks equipment damage but also impacts the nuclear power plant's operational efficiency and may even pose nuclear safety risks. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a transient compensation system for high-temperature gas-cooled reactor nuclear power plant decoupling and its operating method, which can effectively reduce the frequency of accidental shutdowns in high-temperature gas-cooled reactor nuclear power plants and increase overall risk resistance.

[0006] This invention is achieved through the following technical solution:

[0007] The present invention discloses a transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection, comprising a deaerator, a first three-way valve, a first heat exchanger, a second three-way valve, a steam generator, a high-temperature molten salt storage tank, a second heat exchanger, a low-temperature molten salt storage tank, and a molten salt-steam heat exchanger;

[0008] The outlet of the deaerator is connected to the inlet of the first three-way valve. The first outlet of the first three-way valve is connected to the low-temperature inlet of the first heat exchanger. The low-temperature outlet of the first heat exchanger is connected to the first inlet of the second three-way valve. The high-temperature side of the first heat exchanger is connected to the extraction steam from the high-pressure cylinder of the turbine. The second outlet of the first three-way valve is connected to the low-temperature inlet of the second heat exchanger. The low-temperature outlet of the second heat exchanger is connected to the second inlet of the second three-way valve. The outlet of the second three-way valve is connected to the low-temperature inlet of the steam generator. The high-temperature side of the steam generator is connected to the reactor primary loop medium. The low-temperature outlet of the steam generator is connected to the high-temperature inlet of the molten salt-steam heat exchanger and the turbine generator set, respectively. The high-temperature outlet of the molten salt-steam heat exchanger is connected to the inlet of the deaerator. The low-temperature outlet of the molten salt-steam heat exchanger is connected to the high-temperature molten salt storage tank. The high-temperature molten salt storage tank is connected to the high-temperature inlet of the second heat exchanger. The high-temperature outlet of the second heat exchanger is connected to the low-temperature molten salt storage tank. The low-temperature molten salt storage tank is connected to the low-temperature inlet of the molten salt-steam heat exchanger.

[0009] Preferably, a steam shut-off valve and a steam regulating valve are sequentially installed between the low-temperature side outlet of the steam generator and the high-temperature side inlet of the molten salt-steam heat exchanger.

[0010] Preferably, the heat power of the first heat exchanger and the second heat exchanger are equal.

[0011] Preferably, the first heat exchanger is a high-pressure heater and the second heat exchanger is a molten salt heat exchanger.

[0012] Preferably, the first heat exchanger and the second heat exchanger are arranged side by side.

[0013] Preferably, the second heat exchanger includes several heat exchange modules connected in parallel, each of which can be switched in or out.

[0014] Preferably, a water pump is provided between the outlet of the deaerator and the inlet of the first three-way valve.

[0015] Preferably, a cryogenic molten salt pump is provided between the cryogenic molten salt storage tank and the cryogenic side inlet of the molten salt-steam heat exchanger.

[0016] Preferably, a high-temperature molten salt pump is provided between the high-temperature molten salt storage tank and the high-temperature side inlet of the second heat exchanger.

[0017] The operating method of the transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater decoupling disclosed in this invention includes:

[0018] During normal operation of the unit, water in the deaerator enters the first heat exchanger, where it exchanges heat with the steam extracted from the high-pressure cylinder of the turbine to raise its temperature. It then enters the steam generator, where it exchanges heat with the reactor primary loop medium to generate high-temperature and high-pressure steam. Part of the high-temperature and high-pressure steam enters the turbine generator set to generate electricity, while the other part enters the molten salt-steam heat exchanger to exchange heat with the molten salt. The low-temperature molten salt in the low-temperature molten salt storage tank enters the molten salt-steam heat exchanger to absorb heat, and then enters the high-temperature molten salt storage tank for storage. The condensate after heat exchange is recovered to the deaerator.

[0019] When the turbine generator set trips or the high water level alarm in the first heat exchanger triggers the high-pressure heater disconnection protection, the feedwater flowing through the first heat exchanger is switched to the second heat exchanger through the first three-way valve and the second three-way valve. At the same time, the high-temperature molten salt in the high-temperature molten salt storage tank enters the second heat exchanger to heat the feedwater from the deaerator. The low-temperature molten salt after heat exchange in the second heat exchanger enters the low-temperature molten salt storage tank for storage. The heated feedwater enters the steam generator and exchanges heat with the reactor primary loop medium to generate high-temperature and high-pressure steam, which enters the turbine generator set to perform power generation.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] This invention discloses a transient compensation system for HF reactor disconnection in a high-temperature gas-cooled reactor nuclear power plant. During normal unit operation, a portion of steam is drawn from the main steam source to heat cryogenic molten salt. The heat is then transferred to the high-temperature molten salt, which is stored in a high-temperature molten salt storage tank. When a transient condition of HF reactor disconnection occurs, the system automatically switches the feedwater to a standby second heat exchanger. The high-temperature molten salt in the storage tank is then transported to the second heat exchanger to heat the feedwater. The cooled cryogenic molten salt is returned to the cryogenic molten salt storage tank. This system stabilizes the feedwater temperature at the steam generator inlet, further stabilizing the primary loop cold and hot helium temperatures. This prevents reactor shutdowns due to drastic fluctuations in operating conditions, improves the unit's resilience, and ensures stable power generation. It offers high safety and economic benefits.

[0022] Furthermore, the first heat exchanger and the second heat exchanger have equal thermal power, which can respectively meet the heating needs of the full capacity of water supply.

[0023] Furthermore, the second heat exchanger includes several parallel heat exchange modules, each of which can be switched in or out, and can meet the actual heat demand of other heat users for molten salt heat.

[0024] The working method of the high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection transient compensation system disclosed in this invention has a high degree of automation and is easy to control, which improves the safety and stability of reactor operation and has good application prospects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall system structure of the present invention.

[0026] In the diagram: 1 is the deaerator, 2 is the feedwater pump, 3 is the first three-way valve, 4 is the first heat exchanger, 5 is the second three-way valve, 6 is the steam generator, 7 is the high-temperature molten salt storage tank, 8 is the high-temperature molten salt pump, 9 is the second heat exchanger, 10 is the low-temperature molten salt storage tank, 11 is the low-temperature molten salt pump, 12 is the molten salt-steam heat exchanger, 13 is the steam shut-off valve, 14 is the steam regulating valve, 15 is the steam turbine generator set, and 16 is the protection control unit. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This description is intended to explain the invention and not to limit it.

[0028] like Figure 1 The present invention provides a transient compensation system for the decommissioning of a high-temperature gas-cooled reactor nuclear power plant, comprising a deaerator 1, a first three-way valve 3, a first heat exchanger 4, a second three-way valve 5, a steam generator 6, a high-temperature molten salt storage tank 7, a second heat exchanger 9, a low-temperature molten salt storage tank 10, and a molten salt-steam heat exchanger 12.

[0029] The outlet of deaerator 1 is connected to the inlet of the first three-way valve 3. The first outlet of the first three-way valve 3 is connected to the low-temperature side inlet of the first heat exchanger 4. The low-temperature side outlet of the first heat exchanger 4 is connected to the first inlet of the second three-way valve 5. The high-temperature side of the first heat exchanger 4 is connected to the extraction steam from the high-pressure cylinder of the steam turbine. The second outlet of the first three-way valve 3 is connected to the low-temperature side inlet of the second heat exchanger 9. The low-temperature side outlet of the second heat exchanger 9 is connected to the second inlet of the second three-way valve 5. The outlet of the second three-way valve 5 is connected to the low-temperature side inlet of the steam generator 6. The high-temperature side of the steam generator 6... The low-temperature side outlet of the steam generator 6 is connected to the high-temperature side inlet of the molten salt-steam heat exchanger 12 and the steam turbine generator set 15, respectively. The high-temperature side outlet of the molten salt-steam heat exchanger 12 is connected to the inlet of the deaerator 1. The low-temperature side outlet of the molten salt-steam heat exchanger 12 is connected to the high-temperature molten salt storage tank 7. The high-temperature molten salt storage tank 7 is connected to the high-temperature side inlet of the second heat exchanger 9. The high-temperature side outlet of the second heat exchanger 9 is connected to the low-temperature molten salt storage tank 10. The low-temperature molten salt storage tank 10 is connected to the low-temperature side inlet of the molten salt-steam heat exchanger 12.

[0030] Water pump 2, first three-way valve 3, second three-way valve 5, high temperature molten salt pump 8, low temperature molten salt pump 11, steam shut-off valve 13 and steam regulating valve 14 are respectively connected to protection control unit 16. The high temperature heater disconnection protection signal has linkage control logic with first three-way valve 3, second three-way valve 5 and high temperature molten salt pump 8.

[0031] In a preferred embodiment of the present invention, a steam shut-off valve 13 and a steam regulating valve 14 are sequentially provided between the low-temperature side outlet of the steam generator 6 and the high-temperature side inlet of the molten salt-steam heat exchanger 12.

[0032] In a preferred embodiment of the present invention, the thermal power of the first heat exchanger 4 and the second heat exchanger 9 are equal.

[0033] In a preferred embodiment of the present invention, the first heat exchanger 4 is a high-pressure heater, wherein water flows through the tube side and steam flows through the shell side. The second heat exchanger 9 is a molten salt heat exchanger.

[0034] In a preferred embodiment of the present invention, the first heat exchanger 4 and the second heat exchanger 9 are arranged side by side.

[0035] In a preferred embodiment of the present invention, the second heat exchanger 9 includes a plurality of parallel heat exchange modules, each of which can be switched in or out.

[0036] In a preferred embodiment of the present invention, a water pump 2 is provided between the outlet of the deaerator 1 and the inlet of the first three-way valve 3.

[0037] In a preferred embodiment of the present invention, a cryogenic molten salt pump 11 is provided between the cryogenic molten salt storage tank 10 and the cryogenic side inlet of the molten salt-steam heat exchanger 12.

[0038] In a preferred embodiment of the present invention, a high-temperature molten salt pump 8 is provided between the high-temperature molten salt storage tank 7 and the high-temperature side inlet of the second heat exchanger 9.

[0039] The above-mentioned working method of the transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater decoupling:

[0040] Water in deaerator 1 is pressurized by feedwater pump 2, then reheated and heated by first heat exchanger 4 before being transported to steam generator 6 to exchange heat with the reactor primary loop medium to generate high-temperature, high-pressure steam. The steam at the outlet of steam generator 6 is divided into two paths: one path enters turbine generator set 15 to generate electricity, and the other path connects to the steam inlet of molten salt-steam heat exchanger 12 via steam shut-off valve 13 and steam regulating valve 14, where it exchanges heat with molten salt as needed. The condensate from molten salt-steam heat exchanger 12 is recovered to deaerator 1 via pipeline.

[0041] During the heat absorption stage, the low-temperature molten salt in the low-temperature molten salt storage tank 10 is pressurized by the low-temperature molten salt pump 11, absorbs heat from the steam in the molten salt-steam heat exchanger 12, and is then sent to the high-temperature molten salt storage tank 7 for storage. During the heat release stage, the high-temperature molten salt in the high-temperature molten salt storage tank 7 is pressurized by the high-temperature molten salt pump 8, releases heat to the feedwater in the second heat exchanger 9, and is cooled to low-temperature molten salt before entering the low-temperature molten salt storage tank 10 for storage.

[0042] During daily operation, the molten salt circulation system performs heat storage circulation, storing the high-temperature molten salt, after absorbing heat from the steam, in the high-temperature molten salt storage tank 7. The molten salt circulation system maintains the system's operating temperature through an electric heater, ensuring the system has rapid response capabilities. When the turbine generator set 15 trips or the high-level alarm of the first heat exchanger 4 triggers the high-pressure heater disconnection protection, the first three-way valve 3 and the second three-way valve 5 receive instructions from the protection control unit 16 and automatically switch the feedwater flowing through the first heat exchanger 4 to the second heat exchanger 9. Simultaneously, the high-temperature molten salt pump 8 receives a start command and automatically starts, transporting the high-temperature molten salt from the high-temperature molten salt storage tank 7 to the second heat exchanger 9 to heat the feedwater from the deaerator 1. The low-temperature molten salt, after heat exchange in the second heat exchanger 9, enters the low-temperature molten salt storage tank 10 for storage, and the heated feedwater then enters the steam generator 6.

[0043] The above description is merely an embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, or equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, should all be covered within the scope of protection of the present invention.

Claims

1. A transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection, characterized in that, It includes a deaerator (1), a first three-way valve (3), a first heat exchanger (4), a second three-way valve (5), a steam generator (6), a high-temperature molten salt storage tank (7), a second heat exchanger (9), a low-temperature molten salt storage tank (10), and a molten salt-steam heat exchanger (12). The outlet of the deaerator (1) is connected to the inlet of the first three-way valve (3), the first outlet of the first three-way valve (3) is connected to the low-temperature side inlet of the first heat exchanger (4), the low-temperature side outlet of the first heat exchanger (4) is connected to the first inlet of the second three-way valve (5), and the high-temperature side of the first heat exchanger (4) is connected to the extraction steam from the high-pressure cylinder of the steam turbine; the second outlet of the first three-way valve (3) is connected to the low-temperature side inlet of the second heat exchanger (9), and the low-temperature side outlet of the second heat exchanger (9) is connected to the second inlet of the second three-way valve (5); the outlet of the second three-way valve (5) is connected to the low-temperature side inlet of the steam generator (6), and the high-temperature side of the steam generator (6 ... outlet of the steam generator (6) is connected to the extraction steam from the high-pressure cylinder of the steam turbine; the second outlet of the first three-way valve (3) is connected to The temperature side is connected to the reactor primary loop medium. The low temperature side outlet of the steam generator (6) is connected to the high temperature side inlet of the molten salt-steam heat exchanger (12) and the steam turbine generator set (15), respectively. The high temperature side outlet of the molten salt-steam heat exchanger (12) is connected to the inlet of the deaerator (1). The low temperature side outlet of the molten salt-steam heat exchanger (12) is connected to the high temperature molten salt storage tank (7). The high temperature molten salt storage tank (7) is connected to the high temperature side inlet of the second heat exchanger (9). The high temperature side outlet of the second heat exchanger (9) is connected to the low temperature molten salt storage tank (10). The low temperature molten salt storage tank (10) is connected to the low temperature side inlet of the molten salt-steam heat exchanger (12). A steam shut-off valve (13) and a steam regulating valve (14) are sequentially installed between the low-temperature side outlet of the steam generator (6) and the high-temperature side inlet of the molten salt-steam heat exchanger (12). When the turbine generator set (15) trips or the high water level alarm of the first heat exchanger (4) triggers the high pressure relief protection, the first three-way valve (3) and the second three-way valve (5) receive the instruction from the protection control unit (16) and automatically switch the feedwater flowing through the first heat exchanger (4) to the second heat exchanger (9).

2. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, The heat output of the first heat exchanger (4) is equal to that of the second heat exchanger (9).

3. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, The first heat exchanger (4) is a high-pressure heater, and the second heat exchanger (9) is a molten salt heat exchanger.

4. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, The first heat exchanger (4) and the second heat exchanger (9) are arranged side by side.

5. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, The second heat exchanger (9) includes several parallel heat exchange modules, each of which can be switched in or out.

6. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, A water pump (2) is provided between the outlet of the deaerator (1) and the inlet of the first three-way valve (3).

7. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, A cryogenic molten salt pump (11) is provided between the cryogenic molten salt storage tank (10) and the cryogenic side inlet of the molten salt-steam heat exchanger (12).

8. The transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater disconnection according to claim 1, characterized in that, A high-temperature molten salt pump (8) is provided between the high-temperature molten salt storage tank (7) and the high-temperature side inlet of the second heat exchanger (9).

9. The operating method of the transient compensation system for high-temperature gas-cooled reactor nuclear power plant high-temperature heater decoupling according to any one of claims 1 to 8, characterized in that, include: When the unit is running normally, the water in the deaerator (1) enters the first heat exchanger (4), and after exchanging heat with the steam extracted from the high-pressure cylinder of the steam turbine, the temperature is increased. It then enters the steam generator (6), and after exchanging heat with the reactor primary loop medium, high-temperature and high-pressure steam is generated. Part of the high-temperature and high-pressure steam enters the steam turbine generator set (15) to generate electricity, and the other part enters the molten salt-steam heat exchanger (12) to exchange heat with the molten salt. The low-temperature molten salt in the low-temperature molten salt storage tank (10) enters the molten salt-steam heat exchanger (12) to absorb heat, and then enters the high-temperature molten salt storage tank (7) for storage. The condensate after heat exchange is recovered to the deaerator (1). When the turbine generator set (15) trips or the high water level alarm of the first heat exchanger (4) triggers the high-pressure heater disconnection protection, the feedwater flowing through the first heat exchanger (4) is switched to the second heat exchanger (9) through the first three-way valve (3) and the second three-way valve (5); at the same time, the high-temperature molten salt in the high-temperature molten salt storage tank (7) enters the second heat exchanger (9) to heat the feedwater from the deaerator (1); the low-temperature molten salt after heat exchange in the second heat exchanger (9) enters the low-temperature molten salt storage tank (10) for storage, and the heated feedwater enters the steam generator (6) to exchange heat with the reactor primary loop medium to generate high-temperature and high-pressure steam, which enters the turbine generator set (15) to do power generation.

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