A system and method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit

Abstract

The present invention discloses a system and method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit. The system includes a multi-module reactor, a first steam-water separator, a second steam-water separator, a deaerator, a high-pressure heater, a unit drainage tank, a steam turbine and a condenser; the method includes a unit start-up process and a unit stop process. The multi-module reactor nuclear power unit provided by the present invention also starts and stops a reactor one by one during the start-up and stop process. Multiple reactors share two start-stop reactor systems. During the start-up and stop process of the first reactor, the second start-stop reactor system can adjust its parameters to adapt to the parameters of the next reactor to be started and stopped, so the two start-stop reactor systems meet the needs of starting and stopping multiple reactors.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and in particular relates to a system and method for starting and stopping a nuclear power unit with a direct current evaporator of a multi-module reactor. Background Art

[0002] The current 200MW high-temperature gas-cooled reactor demonstration project adopts a modular design. Each module contains a reactor and a start-stop system. According to the current design, if a 600MW high-temperature gas-cooled reactor nuclear power plant is to be built, 6 reactors and 6 start-stop systems will be required. This design system is complex, difficult to arrange, complex to control, expensive, and has poor operating safety, poor operating stability, and poor operating economy. Summary of the invention

[0003] The purpose of the present invention is to provide a system and method for starting and stopping a multi-module nuclear power unit with a direct current evaporator, aiming at the design of a start-stop system for a multi-module nuclear power unit.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A system for starting and stopping a nuclear power unit with a multi-module reactor and a direct current evaporator comprises a multi-module reactor, a first steam-water separator, a second steam-water separator, a deaerator, a high-pressure heater, a unit drainage tank, a steam turbine and a condenser; wherein the multi-module reactor is composed of at least two reactors, the first reactor and the second reactor are two representatives of the multi-module reactor, and the other reactors in the multi-module reactor are completely the same as the first reactor and the second reactor; the outlet steam pipes of the first reactor and the second reactor are divided into two branches, the first branch of the pipe of the first reactor is respectively connected to the first inlet of the first steam-water separator and the second inlet of the second steam-water separator, and the second branch of the pipe of the first reactor is respectively connected to the first inlet of the first steam-water separator and the second inlet of the second steam-water separator, and the second branch of the pipe of the first reactor is respectively connected to the first inlet of the first steam-water separator and the second inlet of the second steam-water separator. The first pipelines of the two reactors are respectively connected to the first inlet of the second steam-water separator and the second inlet of the first steam-water separator; the outlet pipelines of other reactors of the multi-module reactor are also divided into two branches, wherein the first pipelines are respectively connected to the other inlets of the first steam-water separator and the second steam-water separator; the second pipelines of the outlets of the first reactor, the second reactor and other reactors are combined and divided into three branches, the first branch is connected to the inlet of the turbine, the second branch is connected to the second inlet of the condenser, and the third branch is divided into two branches, the first branch is connected to the fifth inlet of the deaerator, and the second branch is connected to the first inlet of the high-pressure heater; the outlet of the steam turbine is connected to the first inlet of the condenser.

[0006] A further improvement of the present invention is that the first outlet of the first steam-water separator and the second steam-water separator is their drain outlet, and the outlet is divided into three branches, the first branch is connected to the first and second inlets of the deaerator respectively, the second branch is connected to the first and second inlets of the unit drainage trough respectively, and the third branch is connected to the third and fifth inlets of the condenser respectively.

[0007] A further improvement of the present invention is that the second outlets of the first steam-water separator and the second steam-water separator are steam exhaust outlets, and the outlets are divided into three streams, the first stream is connected to the third and fourth inlets of the deaerator respectively, the second stream is connected to the second and third inlets of the high-pressure heater, and the third stream is connected to the fourth and sixth inlets of the condenser.

[0008] A further improvement of the present invention is that the first reactor is capable of producing a water vapor mixture at a temperature of 30 to 120° C. and a pressure of 5 MPa to 15 MPa.

[0009] A further improvement of the present invention is that the first steam-water separator can produce saturated steam and saturated water at a pressure of 0.1 MPa to 5 MPa.

[0010] A further improvement of the present invention is that the system is applicable to a 600MW high temperature gas-cooled reactor nuclear power plant.

[0011] A method for starting and stopping a nuclear power unit with a multi-module reactor and a direct current evaporator. The method is based on the system for starting and stopping a nuclear power unit with a multi-module reactor and a direct current evaporator. The unit startup process includes the following steps:

[0012] In the early stage of establishing the secondary water circulation, the outlet of the first reactor is a water vapor mixture with a temperature of 30 to 120°C and a pressure of 5 MPa to 15 MPa. After the high-temperature and high-pressure water vapor mixture enters the first steam-water separator, it expands and reduces the pressure, producing saturated steam and saturated water with a pressure of 0.1 MPa to 5 MPa.

[0013] Part of the saturated steam generated by the first steam-water separator enters the deaerator to heat the water in the deaerator, part of it enters the steam side of the high-pressure heater to heat the water on the water side of the high-pressure heater, and the rest of the steam enters the condenser;

[0014] Test the water produced by the first steam-water separator. If the water quality is unqualified, drain the water to the unit drain tank. If the water quality is qualified, drain the water to the deaerator. When the deaerator cannot accept the qualified water produced by the first steam-water separator, drain it to the condenser.

[0015] As the power of the first reactor increases, the water at its outlet decreases and the steam increases, and finally all becomes superheated steam. The first steam-water separator is removed, and the superheated steam is discharged to the condenser when it does not meet the conditions for entering the steam turbine. When the superheated steam meets the conditions for entering the steam turbine, it enters the steam turbine. As needed, part of the steam enters the high-pressure heater to heat the feed water;

[0016] The startup process of other reactors of the multi-module reactor is the same as that of the first reactor; the steam-water mixture of a reactor at the initial startup is discharged to a steam-water separator having a temperature close to that of the reactor;

[0017] During the operation of the unit, one steam-water separator is kept at a higher temperature as standby, and the other is kept at a lower temperature as standby.

[0018] A method for starting and stopping a nuclear power unit with a multi-module reactor and a direct current evaporator. The method is based on the system for starting and stopping a nuclear power unit with a multi-module reactor and a direct current evaporator. The unit stopping process includes the following steps:

[0019] As the nuclear power of the first reactor decreases, the steam flow and temperature at the outlet of the first reactor decrease. When the steam at the outlet of the first reactor cannot enter the steam turbine, its steam enters the condenser, and part of the steam enters the high-pressure heater as needed.

[0020] As the nuclear power of the first reactor is further reduced, the superheated steam at the outlet of the first reactor is gradually converted into a steam-water mixture. At this time, the steam-water mixture at the outlet of the first reactor enters the first steam-water separator. The steam in the first steam-water separator enters the deaerator, the high-pressure heater or the condenser as needed; the water in the first steam-water separator enters the deaerator or the condenser as needed, and if the water quality is unqualified, it enters the unit drainage tank;

[0021] The shutdown process of other reactors of the multi-module reactor is the same as that of the first reactor; the steam-water mixture of a certain reactor during the shutdown process is discharged to a steam-water separator whose temperature is close to that of the reactor.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The present invention provides a system and method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit. Compared with the currently commonly used system, the system has the following obvious advantages:

[0024] (1) Meeting functional requirements

[0025] For a multi-module reactor nuclear power unit, the start-up and shutdown process is also the start-up and shutdown of one reactor at a time. Multiple reactors share two start-stop systems. During the start-up and shutdown process of the first reactor, the second start-stop system can adjust its parameters to adapt to the parameters of the next reactor to be started and stopped. Therefore, the two start-stop systems meet the needs of starting and stopping multiple reactors and are suitable for 600MW high-temperature gas-cooled reactor nuclear power plants.

[0026] (2) The system is simple, easy to arrange and low in cost

[0027] For multiple reactors, two start-stop loops are configured. Compared with configuring one start-stop loop for each reactor, the system is much simpler, so it is easy to arrange and has low cost.

[0028] (3) Good operating economy, stability and safety

[0029] During the process of starting and stopping the reactor, part of the separator drain and steam can be recovered, so the economy is good. At the same time, due to the use of the auxiliary steam of this machine, the auxiliary steam can be self-sufficient and independent of the external system, so the operation stability and safety are better. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a structural block diagram of a system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit.

[0031] Description of reference numerals:

[0032] 1. First reactor, 2. Second reactor, 3. First steam-water separator, 4. Second steam-water separator, 5. Deaerator, 6. High-pressure heater, 7. Unit drain tank, 8. Steam turbine, 9. Condenser, 10. Multi-module reactor. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, a system for starting and stopping a nuclear power unit with a multi-module reactor direct current evaporator provided by the present invention comprises a multi-module reactor 10, a first steam-water separator 3, a second steam-water separator 4, a deaerator 5, a high-pressure heater 6, a unit drainage tank 7, a steam turbine 8 and a condenser 9; wherein the multi-module reactor 10 is composed of at least two reactors, the first reactor 1 and the second reactor 2 are two representatives of the multi-module reactor 10, and the other reactors in the multi-module reactor 10 are completely the same as the first reactor 1 and the second reactor 2;

[0035] The outlet steam pipes of the first reactor 1 and the second reactor 2 are divided into two branches, the first pipe of the first reactor 1 is respectively connected to the first inlet of the first steam-water separator 3 and the second inlet of the second steam-water separator 4, and the first pipe of the second reactor 2 is respectively connected to the first inlet of the second steam-water separator 4 and the second inlet of the first steam-water separator 3; the outlet pipes of other reactors of the multi-module reactor 10 are also divided into two branches, wherein the first pipes are respectively connected to the other inlets of the first steam-water separator 3 and the second steam-water separator 4; the second pipes of the outlets of the first reactor 1, the second reactor 2 and other reactors are divided into three branches after merging, the first branch is connected to the inlet of the steam turbine 8, the second branch is connected to the second inlet of the condenser 9, and the third branch is divided into two branches, the first branch is connected to the fifth inlet of the deaerator 5, and the second branch is connected to the first inlet of the high-pressure heater 6; the outlet of the steam turbine 8 is connected to the first inlet of the condenser 9.

[0036] The first outlet of the first steam-water separator 3 and the second steam-water separator 4 is the drain outlet, and the outlet is divided into three branches. The first branch is connected to the first and second inlets of the deaerator 5, the second branch is connected to the first and second inlets of the unit drain trough 7, and the third branch is connected to the third and fifth inlets of the condenser; the second outlet of the first steam-water separator 3 and the second steam-water separator 4 is the steam outlet, and the outlet is divided into three branches. The first branch is connected to the third and fourth inlet of the deaerator 5, the second branch is connected to the second and third inlets of the high-pressure heater 6, and the third branch is connected to the fourth and sixth inlets of the condenser 9.

[0037] The present invention provides a method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit, wherein the unit startup process comprises the following steps:

[0038] In the early stage of establishing the secondary water circulation, the outlet of the first reactor 1 is a high-temperature and high-pressure water-vapor mixture. After the high-temperature and high-pressure water-vapor mixture enters the first steam-water separator 3, it expands and reduces pressure, and generates a certain amount of low-pressure saturated steam and saturated water.

[0039] Part of the saturated steam generated by the first steam-water separator 3 enters the deaerator 5 to heat the water in the deaerator, and part of it enters the steam side of the high-pressure heater 6 to heat the water on the water side of the high-pressure heater. The steam that the high-pressure heater 6 cannot accept enters the condenser 9;

[0040] Test the water produced by the first steam-water separator 3. If the water quality is unqualified, drain the water to the unit drain tank 7. If the water quality is qualified, drain the water to the deaerator 5. When the deaerator 5 cannot accept the qualified water produced by the first steam-water separator 3, drain it to the condenser 9.

[0041] As the power of the first reactor 1 increases, the water at its outlet decreases and the steam increases, and finally all becomes superheated steam. The first steam-water separator 3 is removed, and the superheated steam is discharged to the condenser 9 when it does not meet the conditions for entering the steam turbine 8. When the superheated steam meets the conditions for entering the steam turbine 8, it enters the steam turbine 8. As needed, part of the steam can also enter the high-pressure heater 6 to heat the feed water;

[0042] The startup process of other reactors of the multi-module reactor 10 is the same as the startup process of the first reactor 1; the steam-water mixture of a reactor at the initial startup is discharged to a steam-water separator having a temperature close to that of the reactor;

[0043] During the operation of the unit, one steam-water separator is kept at a higher temperature as standby, and the other is kept at a lower temperature as standby.

[0044] In addition, the unit shutdown process includes the following steps:

[0045] As the nuclear power of the first reactor 1 decreases, the steam flow and temperature at the outlet of the first reactor decrease. When the steam at the outlet of the first reactor 1 cannot enter the steam turbine 8, the steam enters the condenser 9, and part of the steam may also enter the high-pressure heater 6 as needed.

[0046] As the nuclear power of the first reactor 1 is further reduced, the superheated steam at the outlet of the first reactor is gradually converted into a steam-water mixture. At this time, the steam-water mixture at the outlet of the first reactor enters the first steam-water separator 3. The steam in the first steam-water separator 3 enters the deaerator 5, the high-pressure heater 6 or the condenser 9 as needed; the water in the first steam-water separator 3 enters the deaerator 5 or the condenser 9 as needed, and if the water quality is unqualified, it enters the unit drainage tank 7;

[0047] The shutdown process of other reactors of the multi-module reactor 10 is the same as the shutdown process of the first reactor 1; the steam-water mixture of a certain reactor during the shutdown process is discharged to a steam-water separator with a temperature close to that of the reactor.

Claims

1. A system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit, characterized in that: It comprises a multi-module reactor (10), a first steam-water separator (3), a second steam-water separator (4), a deaerator (5), a high-pressure heater (6), a unit drainage tank (7), a steam turbine (8) and a condenser (9); wherein: The multi-module reactor (10) is composed of at least two reactors, wherein the first reactor (1) and the second reactor (2) are two representatives of the multi-module reactor (10), and the other reactors in the multi-module reactor (10) are completely the same as the first reactor (1) and the second reactor (2); the outlet steam pipes of the first reactor (1) and the second reactor (2) are divided into two branches, the first branch of the pipe of the first reactor (1) is respectively connected to the first inlet of the first steam-water separator (3) and the second inlet of the second steam-water separator (4), and the first branch of the pipe of the second reactor (2) is respectively connected to the first inlet of the second steam-water separator (4) and the first steam-water separator. (3); the other reactor outlet pipes of the multi-module reactor (10) are also divided into two branches, wherein the first branch of the pipes are respectively connected to the other inlets of the first steam-water separator (3) and the second steam-water separator (4); the second branch of the pipes at the outlets of the first reactor (1), the second reactor (2) and other reactors are combined and then divided into three branches, the first branch is connected to the inlet of the steam turbine (8), the second branch is connected to the second inlet of the condenser (9), and the third branch is further divided into two branches, the first branch is connected to the fifth inlet of the deaerator (5), and the second branch is connected to the first inlet of the high-pressure heater (6); the outlet of the steam turbine (8) is connected to the first inlet of the condenser (9); The first outlet of the first steam-water separator (3) and the second steam-water separator (4) is a drain outlet thereof, and the outlet is divided into three branches, the first branch is respectively connected to the first and second inlets of the deaerator (5), the second branch is respectively connected to the first and second inlets of the unit drainage trough (7), and the third branch is respectively connected to the third and fifth inlets of the condenser; The first reactor (1) is capable of producing a water-steam mixture at a temperature of 30 to 120°C and a pressure of 5 MPa to 15 MPa.

2. A system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit according to claim 1, characterized in that: The second outlets of the first steam-water separator (3) and the second steam-water separator (4) are steam exhaust outlets, and the outlets are divided into three streams. The first stream is connected to the third and fourth inlets of the deaerator (5), respectively; the second stream is connected to the second and third inlets of the high-pressure heater (6); and the third stream is connected to the fourth and sixth inlets of the condenser (9).

3. The system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit according to claim 1, characterized in that: The first steam-water separator (3) is capable of generating saturated steam and saturated water at a pressure of 0.1 MPa to 5 MPa.

4. The system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit according to claim 1, characterized in that: The system is suitable for 600MW high temperature gas-cooled reactor nuclear power plants.

5. A method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit, characterized in that: The method is based on a system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit according to any one of claims 1 to 4, and the unit startup process includes the following steps: In the initial stage of establishing the secondary water circulation of the first reactor (1), the outlet thereof is a water vapor mixture with a temperature of 30 to 120° C. and a pressure of 5 MPa to 15 MPa. The high-temperature and high-pressure water vapor mixture enters the first steam-water separator (3) and expands and reduces the pressure, thereby producing saturated steam and saturated water with a pressure of 0.1 MPa to 5 MPa. A portion of the saturated steam generated by the first steam-water separator (3) enters the deaerator (5) to heat the water in the deaerator, a portion enters the steam side of the high-pressure heater (6) to heat the water on the water side of the high-pressure heater, and the remaining steam enters the condenser (9); Testing the water produced by the first steam-water separator (3); if the water quality is unqualified, draining the water to the unit drain tank (7); if the water quality is qualified, draining the water to the deaerator (5); when the deaerator (5) cannot accept the qualified water produced by the first steam-water separator (3), draining the water to the condenser (9); As the power of the first reactor (1) increases, the water at its outlet decreases and the steam increases, and finally all of it turns into superheated steam. The first steam-water separator (3) is cut off, and the superheated steam is discharged to the condenser (9) when it is not qualified to enter the steam turbine (8). When the superheated steam is qualified to enter the steam turbine (8), it enters the steam turbine (8), and part of the steam enters the high-pressure heater (6) to heat the feed water as needed; The startup process of other reactors of the multi-module reactor (10) is the same as the startup process of the first reactor (1); the steam-water mixture of a reactor at the initial startup stage is discharged to a steam-water separator having a temperature close to that of the reactor; During the operation of the unit, one steam-water separator is kept at a higher temperature as standby, and the other is kept at a lower temperature as standby.

6. A method for starting and stopping a multi-module reactor direct current evaporator nuclear power unit, characterized in that: The method is based on a system for starting and stopping a multi-module reactor direct current evaporator nuclear power unit according to any one of claims 1 to 4, and the unit stopping process includes the following steps: As the nuclear power of the first reactor (1) decreases, the steam flow rate and temperature at the outlet of the first reactor decrease. When the steam at the outlet of the first reactor (1) cannot enter the steam turbine (8), the steam enters the condenser (9), and part of the steam enters the high-pressure heater (6) as required. As the nuclear power of the first reactor (1) is further reduced, the superheated steam at the outlet of the first reactor is gradually transformed into a steam-water mixture. At this time, the steam-water mixture at the outlet of the first reactor enters the first steam-water separator (3). The steam in the first steam-water separator (3) enters the deaerator (5), the high-pressure heater (6) or the condenser (9) as required. The water in the first steam-water separator (3) enters the deaerator (5) or the condenser (9) as required. If the water quality is unqualified, it enters the unit drainage tank (7). The shutdown process of other reactors of the multi-module reactor (10) is the same as the shutdown process of the first reactor (1); the steam-water mixture of a certain reactor during the shutdown process is discharged to a steam-water separator with a temperature close to that of the reactor.

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