Multi-steam-source multipurpose auxiliary steam system of high-temperature gas cooled reactor

Abstract

The invention particularly relates to a multi-steam-source multipurpose auxiliary steam system of a high-temperature gas cooled reactor, which belongs to the technical field of nuclear power supply of the high-temperature gas cooled reactor and comprises an auxiliary steam header, a plurality of auxiliary steam sources and a plurality of auxiliary steam users, the auxiliary steam distribution system is used for distributing auxiliary steam from one or more auxiliary steam sources to one or more auxiliary steam users in the starting, normal operation or shutdown period of the high-temperature gas cooled reactor unit, and qualified auxiliary steam is provided for the one or more auxiliary steam users. Stable steam supply of the system under the working conditions of starting, stopping, normal operation and accidents of the high-temperature gas cooled reactor unit is effectively guaranteed, meanwhile, the operation duration of the auxiliary boiler is remarkably shortened, and a brand new technical path is provided for efficient operation, energy conservation and emission reduction of nuclear power.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature gas-cooled reactor nuclear power supply, in particular to a high-temperature gas-cooled reactor multi-steam source multi-purpose auxiliary steam system. BACKGROUND

[0002] Nuclear energy, as a clean and low-carbon energy source, plays an irreplaceable role in environmental protection. During the entire operation cycle of a nuclear power plant, almost no atmospheric pollutants such as carbon dioxide and sulfur dioxide are produced, and no nitrogen oxides and dust are emitted. Compared with a thermal power plant of the same scale, a million-kilowatt nuclear power plant can reduce several million tons of carbon dioxide emissions per year, which is crucial for mitigating global climate change and improving air quality. Developing nuclear energy can reduce dependence on imported fossil energy and enhance the autonomy and stability of energy supply. In addition, nuclear energy technology is constantly innovating, and the new generation of nuclear power plants can effectively reduce the risk of nuclear accidents with advanced safety design concepts and technologies.

[0003] As a representative of the fourth-generation advanced nuclear energy system, the high-temperature gas-cooled reactor nuclear power plant further enhances the advantages of nuclear energy. In terms of safety, the high-temperature gas-cooled reactor uses all-ceramic coated particle fuel and high-temperature resistant graphite moderator, which has a negative feedback characteristic that automatically reduces reactivity when the core temperature rises, achieving "inherent safety"; its passive residual heat removal system does not require external energy to remove the residual heat of the core, fundamentally avoiding core meltdown, and greatly improving the safety of nuclear power plant operation. In terms of application, the high-temperature gas-cooled reactor not only can generate electricity, but also can provide high-temperature process heat up to 900℃, promoting the low-carbon transformation of the industrial field. Modular design makes the construction scale flexible, further enhancing the adaptability and reliability of energy supply.

[0004] However, in the traditional high-temperature gas-cooled reactor nuclear power auxiliary steam supply system, auxiliary steam mainly relies on two steam supply modes of auxiliary boiler steam generation and main steam pressure reduction, which has the problems of insufficient energy utilization flexibility and limited operating adaptability. SUMMARY

[0005] The purpose of the present application is to solve the problem of insufficient energy utilization flexibility and limited operating adaptability in the traditional high-temperature gas-cooled reactor nuclear power auxiliary steam supply system, which mainly relies on two steam supply modes of auxiliary boiler steam generation and main steam pressure reduction. The present application provides a high-temperature gas-cooled reactor multi-steam source multi-purpose auxiliary steam system, which effectively ensures stable steam supply of the system under high-temperature gas-cooled reactor unit start-stop, normal operation and accident conditions, and significantly reduces the operation time of auxiliary boilers, providing a new technical path for efficient operation and energy saving and emission reduction of nuclear power.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] A kind of high temperature gas cooled reactor multi-steam source multipurpose auxiliary steam system, including auxiliary steam header, multiple auxiliary steam sources and multiple auxiliary steam users respectively with auxiliary steam header pipeline connection, for high temperature gas cooled reactor unit start-up, normal operation or during shutdown the auxiliary steam from one or more auxiliary steam source distribution to one or more auxiliary steam users, for one or more auxiliary steam users provide qualified auxiliary steam.

[0008] As one of the ways that can be realized, the high temperature gas cooled reactor unit includes a primary circuit and a secondary circuit;The primary circuit includes a reactor core, a steam generator, a primary coolant of the steam generator shell side, a secondary circuit feedwater of the steam generator tube side, and a helium circulating fan at the top of the steam generator;The secondary circuit includes a feedwater pump, a deaerator, a high-pressure heater, a low-pressure heater, a condensate pump, a condenser, a steam turbine and a generator;

[0009] The reactor core is connected to the primary coolant inlet pipeline of the steam generator, the steam generator main steam outlet pipeline is connected to the steam inlet of the high-pressure cylinder of the steam turbine, and the steam turbine is connected to the generator;

[0010] The heat generated by the reactor core is carried to the steam generator by the primary coolant, and the heat is transferred to the secondary circuit feedwater to generate superheated steam, i.e. main steam;

[0011] The high-pressure cylinder of the steam turbine has 8 stages of steam extraction ports for extracting steam for heating the secondary circuit feedwater of the high-pressure heater and the low-pressure heater;The steam extracted from the sixth stage of the high-pressure cylinder of the steam turbine is the sixth stage extraction steam;

[0012] The main steam is expanded in the low-pressure cylinder of the steam turbine, and is discharged to the condenser through the steam exhaust port of the low-pressure cylinder to form condensate, which is sent to the low-pressure heater by the condensate pump, then to the deaerator for deaeration, and then to the high-pressure heater for heating by the feedwater pump, and finally to the steam generator.

[0013] As one of the ways that can be realized, the auxiliary steam source includes main steam from the steam generator of the high temperature gas cooled reactor unit, sixth stage extraction steam from the high-pressure cylinder of the steam turbine, steam from the auxiliary boiler and the heating system, and steam from other high temperature gas cooled reactor units;

[0014] The auxiliary steam user includes the deaerator, the shaft seal system, the heating system, the heating and heat exchange station, the nuclear island heating and heat exchanger, the vacuum system and the steam generator of the high temperature gas cooled reactor unit, the heating system includes the high-pressure heater and the low-pressure heater, and the vacuum system includes the vacuum pump steam ejector;

[0015] The high-temperature gas cooled reactor unit shutdown includes high-temperature gas cooled reactor unit shutdown maintenance and high-temperature gas cooled reactor unit emergency shutdown; during the startup and shutdown of the high-temperature gas cooled reactor unit, the auxiliary steam system provides auxiliary steam to the deaerator, and the deaerator heats the secondary circuit water using the auxiliary steam;

[0016] During the startup, normal operation and shutdown maintenance of the high-temperature gas cooled reactor unit, the auxiliary steam system provides auxiliary steam to the shaft seal system, the high-pressure heater, the low-pressure heater, the heating heat exchange station, the nuclear island heating heat exchanger and the steam ejector of the vacuum pump;

[0017] During the emergency shutdown of the high-temperature gas cooled reactor unit, the auxiliary steam system provides cooling steam to the steam generator and turbine shaft seal steam to the shaft seal system.

[0018] As one of the realizable modes, the auxiliary steam header includes a first auxiliary steam header (1) and a second auxiliary steam header (2); the deaerator includes a first deaerator (3) and a second deaerator (4);

[0019] The main steam from the steam generator and the six-stage extraction steam from the high-pressure cylinder of the turbine are respectively transported to the first auxiliary steam header (1) through the main steam and extraction steam regulating valves (5), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13) pipeline; the main steam from the steam generator and the six-stage extraction steam from the high-pressure cylinder of the turbine are respectively transported to the second auxiliary steam header (2) through the main steam and extraction steam regulating valves (5), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14) pipeline;

[0020] The steam from the auxiliary boiler is transported to the first auxiliary steam header (1) through the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13) pipeline; the steam from the auxiliary boiler is transported to the second auxiliary steam header (2) through the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14) pipeline;

[0021] The steam from the heating system is transported to the first auxiliary steam header (1) through the heating system regulating valve (11), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13) pipeline; the steam from the heating system is transported to the second auxiliary steam header (2) through the heating system regulating valve (11), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14) pipeline;

[0022] Steam from other units is delivered to the first auxiliary steam header (1) through the second stage system regulating valve (12), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); steam from other units is delivered to the second auxiliary steam header (2) through the second stage system regulating valve (12), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14);

[0023] The first auxiliary steam header (1) is connected with the first deaerator (3), the shaft seal system, the high-pressure heater, the low-pressure heater, the heating heat exchange station, the nuclear island heating heat exchanger, the steam ejector of the vacuum pump and the steam generator of the high-temperature gas cooled reactor unit through pipelines, and the pipeline connected with the first deaerator (3) is provided with the first deaerator regulating valve (9); the second auxiliary steam header (2) is connected with the second deaerator (4), the shaft seal system, the high-pressure heater, the low-pressure heater, the heating heat exchange station, the nuclear island heating heat exchanger, the steam ejector of the vacuum pump and the steam generator of the high-temperature gas cooled reactor unit through pipelines, and the pipeline connected with the second deaerator (4) is provided with the second deaerator regulating valve (10);

[0024] The first auxiliary steam header (1) is connected with the first exhaust valve (7) through a pipeline, and the second auxiliary steam header (2) is connected with the second exhaust valve (8) through a pipeline.

[0025] As one of the implementable modes, before the main steam from the steam generator and the six-stage extraction steam from the high-pressure cylinder of the steam turbine meet the conditions of supplying steam to each auxiliary steam user or auxiliary steam system, the auxiliary steam from the auxiliary boiler is delivered to the following auxiliary steam users: the deaerator, the steam ejector of the vacuum pump, the shaft seal system, the high-pressure heater, the low-pressure heater and the start-stop reactor system.

[0026] When the high-temperature gas cooled reactor unit is started for the first time or the high-temperature gas cooled reactor unit is operated at a low load, the six-stage extraction steam cannot meet the requirements of the heating heat exchange station, and the steam source of the heating heat exchange station comes from the auxiliary steam system; in this process, the deaerator regulating valve is used to maintain the temperature in the deaerator, and the high-pressure heater is used to achieve the purpose of controlling the feedwater temperature to meet the requirements of the nuclear island.

[0027] As one of the implementable modes, when the temperature of the main steam generated by the nuclear island reaches 370℃, the steam source of the auxiliary steam system is switched from the steam from the auxiliary boiler to the main steam from the steam generator, and the main steam enters the auxiliary steam header through the desuperheater; when the power of the steam turbine is 50% of the full power, the six-stage extraction steam pressure is reduced to 0.5 MPa.a, and the steam source of the auxiliary steam system is switched from the six-stage extraction steam to the main steam.

[0028] As one of the implementable modes, when the high-temperature gas cooled reactor unit load increases, the six-stage extraction steam pressure reaches 0.797 MPa.a, the steam source of the auxiliary steam system is switched from the main steam to the six-stage extraction steam; the six-stage extraction steam supplies steam to the deaerator and the auxiliary steam header.

[0029] As one of the implementable modes, the heating system uses the main steam of the high-temperature gas cooled reactor steam generator to heat the desalted water to generate external steam, including various superheaters, low-pressure evaporators and preheaters.

[0030] In the condition that the auxiliary boiler is in cold standby and the reactor is in emergency shutdown, the auxiliary steam system uses the low-pressure evaporator waste heat flash steam of the heating system as the turbine shaft seal steam.

[0031] As one of the implementable modes, the auxiliary steam system of the high-temperature gas cooled reactor unit and other high-temperature gas cooled reactor units are provided with a communication pipe;

[0032] After the high-temperature gas cooled reactor unit and other high-temperature gas cooled reactor units are put into operation, the auxiliary steam systems of the high-temperature gas cooled reactor unit and other high-temperature gas cooled reactor units are connected in parallel and run together to maintain the pressure stability of the auxiliary steam systems of the high-temperature gas cooled reactor unit and other high-temperature gas cooled reactor units.

[0033] When one high-temperature gas cooled reactor unit is under maintenance, start-up or shutdown, steam is supplied by another high-temperature gas cooled reactor unit.

[0034] As one of the implementable modes, the auxiliary boiler has three operation conditions: normal operation, hot standby and cold standby; the normal operation refers to any operation condition between the minimum flow of 0.5 t / h and the rated flow of 50 t / h; the cold standby refers to a standby operation condition that the auxiliary boiler is filled with cold water; the hot standby refers to a standby operation condition that the auxiliary boiler is in a hot state by means of an electric heater;

[0035] The auxiliary boiler is in cold standby for a long time and has the ability to switch from cold standby to normal operation in a manual and rapid automatic manner; if the main steam cannot meet the steam requirement of the auxiliary steam during the start-up and shutdown stage of the high-temperature gas cooled reactor unit, the auxiliary boiler is put into operation.

[0036] The beneficial technical effects of the present application are as follows:

[0037] The high-temperature gas cooled reactor multi-steam source multi-purpose auxiliary steam system of the present application is provided with two safety valves to prevent overpressure of the auxiliary steam header, which are sequentially opened when overpressure occurs; the system can automatically switch the steam source of the auxiliary steam system, the normal steam source of the auxiliary steam system adopts six-stage extraction steam of the high-pressure cylinder, and the starting and standby steam source comes from the main steam desuperheating and pressure reducing and auxiliary boiler steam supply; two auxiliary steam headers are designed, which receive steam from the auxiliary boiler when the high-temperature gas cooled reactor unit starts, thereby improving the reliability of the system and having online maintenance conditions, and ensuring continuous operation of the unit for heating; the auxiliary steam system can be used for emergency supply of shaft seal steam of cogeneration units to ensure reliable and stable supply of shaft seal steam of the steam turbine after emergency shutdown; the auxiliary steam system is connected with multiple units, which further increases the steam supply source of the auxiliary steam system and improves the reliability of the auxiliary steam system; and the system can meet the multi-purpose utilization at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The figure is a structural schematic view of one embodiment of the high-temperature gas cooled reactor multi-steam source multi-purpose auxiliary steam system of the present application.

[0039] In the figure, 1 is a first auxiliary steam header, 2 is a second auxiliary steam header, 3 is a first deaerator, 4 is a second deaerator, 5 is a main steam and extraction steam regulating valve, 6 is a heating gas regulating valve, 7 is a first exhaust valve, 8 is a second exhaust valve, 9 is a first deaerator inlet regulating valve, 10 is a second deaerator inlet regulating valve, 11 is a heating system regulating valve, 12 is a regulating valve of other units, 13 is a first auxiliary steam header inlet regulating valve, and 14 is a second auxiliary steam header inlet regulating valve. DETAILED DESCRIPTION

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing the particular embodiments only and is not intended to be limiting of the application.

[0041] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be incorporated into any other embodiment.

[0042] In the description of the present application, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" and the like should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium. The specific meanings of the above terms can be understood according to the specific circumstances for those of ordinary skill in the art.

[0043] The terms "first", "second", "third" and the like are merely for distinguishing similar attributes, and do not indicate or imply relative importance or a particular order.

[0044] The term "comprising" or "including" or any other variant thereof, is intended to cover non-exclusive inclusion, in addition to the listed elements, other elements not explicitly listed can also be included.

[0045] The embodiment provides a high-temperature gas cooled reactor multi-steam source multi-purpose auxiliary steam system, comprising an auxiliary steam header, a plurality of auxiliary steam sources and a plurality of auxiliary steam users connected with the auxiliary steam header pipeline respectively, for distributing auxiliary steam from one or more auxiliary steam sources to one or more auxiliary steam users during high-temperature gas cooled reactor unit startup, normal operation or shutdown, and providing qualified auxiliary steam for one or more auxiliary steam users.

[0046] Referring to Figure 1 In the embodiment, as one of the implementable modes, the high-temperature gas cooled reactor unit comprises a primary loop and a secondary loop;

[0047] The primary loop comprises a reactor core, a steam generator, a primary loop coolant on the shell side of the steam generator, a secondary loop feedwater on the tube side of the steam generator, and a helium circulating fan on the top of the steam generator;

[0048] The secondary loop comprises a feedwater pump, a deaerator, a high-pressure heater, a low-pressure heater, a condensate pump, a condenser, a steam turbine and a generator;

[0049] The reactor core is connected with a primary loop coolant inlet pipeline of the steam generator, a main steam outlet pipeline of the steam generator is connected with a high-pressure cylinder steam inlet of the steam turbine, and a low-pressure cylinder exhaust pipeline of the steam turbine is connected with the condenser, the condensate pump, the low-pressure heater, the deaerator, the feedwater pump, the high-pressure heater and a steam generator feedwater inlet; the steam turbine is connected with the generator;

[0050] The heat generated by the reactor core is taken to the steam generator by the primary loop coolant helium, the heat is transferred to the secondary loop feedwater, superheated steam is generated, and the superheated steam is the main steam;

[0051] The high-pressure cylinder of the steam turbine has eight extraction ports, which are used to extract steam to heat the feedwater of the secondary circuit for the high-pressure heater and the low-pressure heater; the steam extracted from the sixth extraction port of the high-pressure cylinder of the steam turbine is the sixth-stage extraction steam.

[0052] After the main steam expands and works in the low-pressure cylinder of the steam turbine, it is discharged to the condenser through the exhaust port of the low-pressure cylinder to form condensate. The condensate is then pumped to the low-pressure heater, then to the deaerator for deoxygenation, and finally to the high-pressure heater for heating by the feedwater pump before being sent to the steam generator.

[0053] In this embodiment, as one possible approach, the auxiliary steam source includes main steam from the steam generator of the high-temperature gas-cooled reactor unit, sixth-stage extraction steam from the high-pressure cylinder of the turbine, steam from the steam heating system of the auxiliary boiler, and steam from other high-temperature gas-cooled reactor units.

[0054] Auxiliary steam users include the deaerator, shaft sealing system, heating system, heating heat exchange station, nuclear island heating heat exchanger, vacuum system, and steam generator of the high-temperature gas-cooled reactor unit; the heating system includes high-pressure heaters and low-pressure heaters, with 5 low-pressure heaters and 2 high-pressure heaters. The high-pressure heaters, low-pressure heaters, and deaerator are connected in series to heat the secondary loop feedwater and improve the thermal efficiency of the high-temperature gas-cooled reactor unit; the vacuum system includes vacuum pump steam ejectors;

[0055] High-temperature gas-cooled reactor unit shutdown includes high-temperature gas-cooled reactor unit shutdown for maintenance and high-temperature gas-cooled reactor unit emergency shutdown; during the startup and shutdown of the high-temperature gas-cooled reactor unit, the auxiliary steam system provides auxiliary steam to the deaerator, and the deaerator uses the auxiliary steam to heat the secondary loop feedwater.

[0056] During the startup, normal operation, and shutdown maintenance of the high-temperature gas-cooled reactor unit, the auxiliary steam system provides auxiliary steam to the shaft sealing system, high-pressure heater, low-pressure heater, heating heat exchange station, nuclear island heating heat exchanger, and vacuum pump steam ejector.

[0057] During an emergency shutdown of a high-temperature gas-cooled reactor unit, the auxiliary steam system supplies cooling steam to the steam generator and turbine shaft sealing steam to the shaft sealing system.

[0058] In this embodiment, as one possible implementation, the auxiliary steam header includes a first auxiliary steam header (1) and a second auxiliary steam header (2); the deaerator includes a first deaerator (3) and a second deaerator (4);

[0059] The main steam from the steam generator and the six-stage steam extraction from the high-pressure cylinder of the steam turbine are respectively delivered to the first auxiliary steam header (1) through the main steam and extraction regulating valves (5), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); the main steam from the steam generator and the six-stage steam extraction from the high-pressure cylinder of the steam turbine are respectively delivered to the second auxiliary steam header (2) through the main steam and extraction regulating valves (5), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14);

[0060] The steam from the auxiliary boiler room is delivered to the first auxiliary steam header (1) through the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); the steam from the auxiliary boiler room is delivered to the second auxiliary steam header (2) through the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14);

[0061] The steam from the heating system is delivered to the first auxiliary steam header (1) through the heating system regulating valve (11), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); the steam from the heating system is delivered to the second auxiliary steam header (2) through the heating system regulating valve (11), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14);

[0062] The steam from other units is delivered to the first auxiliary steam header (1) through the secondary system regulating valve (12), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); the steam from other units is delivered to the second auxiliary steam header (2) through the secondary system regulating valve (12), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14);

[0063] The first auxiliary steam header (1) is connected with the first deaerator (3) of the high-temperature gas cooled reactor unit, the shaft seal system, the high-pressure heater, the low-pressure heater, the heating heat exchange station, the nuclear island heating heat exchanger, the steam ejector of the vacuum pump and the steam generator through pipelines, and the first deaerator regulating valve (9) is arranged on the pipeline connected with the first deaerator (3); the second auxiliary steam header (2) is connected with the second deaerator (4) of the high-temperature gas cooled reactor unit, the shaft seal system, the high-pressure heater, the low-pressure heater, the heating heat exchange station, the nuclear island heating heat exchanger, the steam ejector of the vacuum pump and the steam generator through pipelines, and the second deaerator regulating valve (10) is arranged on the pipeline connected with the second deaerator (4);

[0064] The first auxiliary steam header (1) is connected with the first exhaust valve (7) through a pipeline, and the second auxiliary steam header (2) is connected with the second exhaust valve (8) through a pipeline.

[0065] In this embodiment, as one of the realizable modes, before the main steam from the desuperheating and pressure-reducing steam generator and the six-stage extraction steam from the high-pressure cylinder of the steam turbine meet the conditions for supplying steam to each auxiliary steam user or auxiliary steam system, the auxiliary steam from the auxiliary boiler is transported to the following users: deaerator, vacuum pump steam ejector, shaft seal system, high-pressure heater, low-pressure heater and start-stop system;

[0066] When the high-temperature gas cooled reactor unit is started for the first time or is operated at low load, the six-stage extraction steam cannot meet the requirements of the heating and heat exchange station, and the steam source of the heating and heat exchange station comes from the auxiliary steam system;

[0067] In this process, the deaerator maintains the pressure in the deaerator by using the deaerator regulating valve, and the high-pressure heater and the low-pressure heater are combined to control the feedwater temperature to meet the requirements of the nuclear island.

[0068] In this embodiment, as one of the realizable modes, when the main steam temperature generated by the nuclear island reaches 370 DEG C, the steam source of the auxiliary steam system is switched from the steam from the auxiliary boiler house to the main steam from the steam generator, and the main steam enters the auxiliary steam header through the desuperheater and pressure reducer; when the power of the steam turbine is 50% of the full power, the six-stage extraction steam pressure is reduced to 0.5 MPa.a, and the steam source of the auxiliary steam system is switched from the six-stage extraction steam to the main steam.

[0069] In this embodiment, as one of the realizable modes, as the load of the high-temperature gas cooled reactor unit increases, when the six-stage extraction steam pressure reaches 0.797 MPa.a, the steam source of the auxiliary steam system is switched from the main steam to the six-stage extraction steam; the six-stage extraction steam supplies steam to the deaerator and the auxiliary steam header.

[0070] The auxiliary boiler is in a cold standby state, and it takes a certain time to start under load, and in the emergency shutdown condition of the reactor, in order to ensure the safety of the turbine shutdown process, an emergency steam source is needed to meet the shaft seal requirements of the turbine.

[0071] In this embodiment, as one of the realizable modes, the heating system uses the main steam of the high-temperature gas cooled reactor steam generator to heat the desalted water to generate external steam, including various superheaters, low-pressure evaporators and preheaters;

[0072] In the cold standby state of the auxiliary boiler and the emergency shutdown condition of the reactor, an emergency steam supply loop is arranged in the auxiliary steam system, the heat capacity of the equipment and the pipeline is considered, the low-pressure evaporator waste heat flash of the heating system is used as an emergency steam source, and the shaft seal steam demand for 2 hours is met.

[0073] In this embodiment, as one of the realizable modes, a communication pipe is arranged between the auxiliary steam system of the high-temperature gas cooled reactor unit and the auxiliary steam system of other high-temperature gas cooled reactor units;

[0074] After all the high-temperature gas cooled reactor units and other high-temperature gas cooled reactor units are put into operation, the auxiliary steam systems of the high-temperature gas cooled reactor units and other high-temperature gas cooled reactor units are connected in grid operation, and the pressure of the auxiliary steam systems of the high-temperature gas cooled reactor units and other high-temperature gas cooled reactor units is stably maintained;

[0075] When one high-temperature gas cooled reactor unit is under maintenance, start-up or shutdown, steam is supplied by another high-temperature gas cooled reactor unit, and steam supplied by the auxiliary boiler is avoided as much as possible, thereby increasing the economy and reliability of the operation of the auxiliary steam system.

[0076] During the start-up and shutdown stages of the high-temperature gas cooled reactor unit, if the main steam cannot meet the steam supply requirement of the auxiliary steam, the auxiliary boiler needs to be put into operation. Therefore, the auxiliary boiler is in an intermittent operation state, and the operation state of the auxiliary boiler is directly related to the auxiliary steam demand.

[0077] In this embodiment, as one of the implementable modes, the auxiliary boiler has three operation modes: normal operation, hot standby and cold standby.

[0078] The normal operation refers to any operation condition between the minimum flow of 0.5 t / h and the rated flow of 50 t / h; the cold standby refers to a standby operation condition in which the auxiliary boiler is filled with cold water to prevent corrosion and thereby protect the auxiliary boiler; and the hot standby refers to a standby operation condition in which the auxiliary boiler is in a hot state by means of an electric heater, and can be quickly put into the normal operation state at any time.

[0079] Although the auxiliary boiler is often in the cold standby state, it is still one of the important auxiliary steam sources, and should be able to be automatically put into operation at any time; the auxiliary boiler can also be switched from the cold standby state to the normal operation state in a manual manner; therefore, the availability and quick start are very important; during the long-term cold standby period, the auxiliary boiler needs to be protected to prevent corrosion or other problems, so that the auxiliary boiler is in a good state and can be put into operation at any time.

[0080] The above high-temperature gas cooled reactor multi-steam source multi-purpose auxiliary steam system comprises the following steps:

[0081] The auxiliary steam for the start-up of the high-temperature gas cooled reactor unit is from the auxiliary boiler; when the main steam has the condition of supplying steam to each user or the auxiliary steam system, the steam source of the auxiliary steam is switched from the auxiliary boiler house to the main steam; when the extraction steam has the condition of supplying steam to each user or the auxiliary steam system, the steam source of the auxiliary steam is switched from the main steam to the six-stage extraction steam.

[0082] Since the shaft seal steam needs to be maintained during the load rejection and shutdown process of the steam turbine, if the main steam condition is not available, the auxiliary steam in this condition is from the low-pressure evaporator of the heat supply system, and only the shaft seal is supplied with steam before shutdown.

[0083] The auxiliary steam system delivers required steam to auxiliary steam users: 1) before the main steam or the sixth stage extraction steam has the condition of supplying steam to each auxiliary steam user or auxiliary steam system, the auxiliary steam of the auxiliary boiler is delivered to each auxiliary steam user; 2) before the sixth stage extraction steam has the condition of supplying steam to each auxiliary steam user or auxiliary steam system, the main steam is delivered to each auxiliary steam user after being reduced in temperature and pressure; 3) during the low load stage of the high temperature gas cooled reactor unit, the auxiliary steam is provided by the main steam after being reduced in temperature and pressure; during the high load stage of the high temperature gas cooled reactor unit, the auxiliary steam is provided by the sixth stage extraction steam.

[0084] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A multi-source, multi-purpose auxiliary steam system for a high-temperature gas-cooled reactor, characterized in that, It includes an auxiliary steam header, multiple auxiliary steam sources and multiple auxiliary steam users connected to the auxiliary steam header piping, and is used to distribute auxiliary steam from one or more auxiliary steam sources to one or more auxiliary steam users during the start-up, normal operation or shutdown of the high-temperature gas-cooled reactor unit, and to provide qualified auxiliary steam to one or more auxiliary steam users.

2. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, The high-temperature gas-cooled reactor unit includes a primary loop and a secondary loop; the primary loop includes the reactor core, a steam generator, the primary loop coolant on the shell side of the steam generator, the secondary loop feedwater on the tube side of the steam generator, and a helium circulation fan on top of the steam generator; the secondary loop includes feedwater pumps, a deaerator, a high-pressure heater, a low-pressure heater, a condensate pump, a condenser, a steam turbine, and a generator. The reactor core is connected to the coolant inlet pipe of the primary loop of the steam generator; the main steam outlet pipe of the steam generator is connected to the steam inlet of the high-pressure cylinder of the steam turbine; the exhaust pipe of the low-pressure cylinder of the steam turbine is connected to the condenser, condensate pump, low-pressure heater, deaerator, feedwater pump, high-pressure heater and steam generator feedwater inlet; the steam turbine is connected to the generator. The heat generated in the reactor core is carried to the steam generator through the primary coolant, and then transferred to the secondary feedwater to produce superheated steam, which is the main steam. The high-pressure cylinder of the steam turbine has eight extraction ports, which are used to extract steam to heat the feedwater of the secondary circuit for the high-pressure heater and the low-pressure heater; the steam extracted from the sixth extraction port of the high-pressure cylinder of the steam turbine is the sixth-stage extraction steam. After the main steam expands and works in the low-pressure cylinder of the steam turbine, it is discharged to the condenser through the exhaust port of the low-pressure cylinder to form condensate. The condensate is then pumped to the low-pressure heater, then to the deaerator for deoxygenation, and finally to the high-pressure heater for heating by the feedwater pump before being sent to the steam generator.

3. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, The auxiliary steam sources include main steam from the steam generator of the high-temperature gas-cooled reactor unit, six-stage extraction steam from the high-pressure cylinder of the turbine, steam from the auxiliary boiler and the heating system, as well as steam from other high-temperature gas-cooled reactor units. Auxiliary steam users include the deaerator, shaft sealing system, heating system, heating heat exchange station, nuclear island heating heat exchanger, vacuum system and steam generator of the high temperature gas-cooled reactor unit. The heating system includes high pressure heater and low pressure heater, and the vacuum system includes vacuum pump steam ejector. High-temperature gas-cooled reactor unit shutdown includes high-temperature gas-cooled reactor unit shutdown for maintenance and high-temperature gas-cooled reactor unit emergency shutdown; during the startup and shutdown of the high-temperature gas-cooled reactor unit, the auxiliary steam system provides auxiliary steam to the deaerator, and the deaerator uses the auxiliary steam to heat the secondary loop feedwater. During the startup, normal operation, and shutdown maintenance of the high-temperature gas-cooled reactor unit, the auxiliary steam system provides auxiliary steam to the shaft sealing system, high-pressure heater, low-pressure heater, heating heat exchange station, nuclear island heating heat exchanger, and vacuum pump steam ejector. During an emergency shutdown of a high-temperature gas-cooled reactor unit, the auxiliary steam system supplies cooling steam to the steam generator and turbine shaft sealing steam to the shaft sealing system.

4. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, The auxiliary steam header includes a first auxiliary steam header (1) and a second auxiliary steam header (2); the deaerator includes a first deaerator (3) and a second deaerator (4); The main steam from the steam generator and the sixth-stage extraction steam from the high-pressure cylinder of the steam turbine are respectively transported to the first auxiliary steam header (1) via the main steam and extraction steam regulating valve (5), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13) pipelines; the main steam from the steam generator and the sixth-stage extraction steam from the high-pressure cylinder of the steam turbine are respectively transported to the second auxiliary steam header (2) via the main steam and extraction steam regulating valve (5), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14) pipelines. Steam from the auxiliary boiler is transported to the first auxiliary steam header (1) via the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); steam from the auxiliary boiler is transported to the second auxiliary steam header (2) via the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14). Steam from the heating system is transported to the first auxiliary steam header (1) via the heating system regulating valve (11), the heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); steam from the heating system is transported to the second auxiliary steam header (2) via the heating system regulating valve (11), the heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14). Steam from other units is transported to the first auxiliary steam header (1) via the second-phase system regulating valve (12), heating gas regulating valve (6) and the first auxiliary steam header inlet regulating valve (13); steam from other units is transported to the second auxiliary steam header (2) via the second-phase system regulating valve (12), heating gas regulating valve (6) and the second auxiliary steam header inlet regulating valve (14). The first auxiliary steam header (1) is connected to the first deaerator (3), shaft sealing system, high-pressure heater, low-pressure heater, heating heat exchange station, nuclear island heating heat exchanger, vacuum pump steam ejector and steam generator of the high-temperature gas-cooled reactor unit. The first auxiliary steam header (1) is connected to the first deaerator (3) by a regulating valve (9) for the first deaerator. The second auxiliary steam header (2) is connected to the second deaerator (4), shaft sealing system, high-pressure heater, low-pressure heater, heating heat exchange station, nuclear island heating heat exchanger, vacuum pump steam ejector and steam generator of the high-temperature gas-cooled reactor unit. The second auxiliary steam header (2) is connected to the second deaerator (4) by a regulating valve (10) for the second deaerator. The first auxiliary steam header (1) is connected to a first row of atmospheric valves (7) via a pipeline, and the second auxiliary steam header (2) is connected to a second row of atmospheric valves (8) via a pipeline.

5. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, Before the desuperheated and depressurized main steam from the steam generator and the sixth-stage extraction steam from the high-pressure cylinder of the steam turbine are ready to supply steam to the various auxiliary steam users or auxiliary steam systems, the auxiliary steam from the auxiliary boiler is delivered to the following auxiliary steam users: deaerator, vacuum pump steam ejector, shaft seal system, high-pressure heater, low-pressure heater and reactor start-up and shutdown system. During the initial startup of the high-temperature gas-cooled reactor unit or when the high-temperature gas-cooled reactor unit is operating at low load, the sixth-stage extraction steam cannot meet the requirements of the heating heat exchange station, and the steam source of the heating heat exchange station comes from the auxiliary steam system. During this process, the deaerator uses the deaerator regulating valve to maintain the pressure inside the deaerator, and works in conjunction with the high-pressure heater and the low-pressure heater to control the feedwater temperature to meet the requirements of the nuclear island.

6. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, When the temperature of the main steam generated by the nuclear island reaches 370°C, the steam source of the auxiliary steam system is switched from the steam from the auxiliary boiler to the main steam from the steam generator. The main steam enters the auxiliary steam header through the desuperheater and pressure reducer. When the turbine power is 50% full power and the sixth-stage extraction steam pressure drops to 0.5 MPa, the steam source of the auxiliary steam system is switched from the sixth-stage extraction steam to the main steam.

7. The high-temperature gas-cooled reactor multi-source multi-purpose auxiliary steam system according to claim 1, characterized in that, As the load on the high-temperature gas-cooled reactor unit increases, when the sixth-stage extraction steam pressure reaches 0.797 MPa, the steam source for the auxiliary steam system is switched from the main steam to the sixth-stage extraction steam; the sixth-stage extraction steam supplies steam to the deaerator and the auxiliary steam header.

8. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 1, characterized in that, A connecting pipe is installed between the auxiliary steam systems of the high-temperature gas-cooled reactor unit and other high-temperature gas-cooled reactor units; After the high-temperature gas-cooled reactor unit and other high-temperature gas-cooled reactor units are put into operation, the auxiliary steam systems of the high-temperature gas-cooled reactor unit and other high-temperature gas-cooled reactor units are connected to the grid to jointly maintain the pressure stability of the auxiliary steam systems of the high-temperature gas-cooled reactor unit and other high-temperature gas-cooled reactor units. When one high-temperature gas-cooled reactor unit is under maintenance, started up, or shut down, steam is supplied by another high-temperature gas-cooled reactor unit.

9. The high-temperature gas-cooled reactor multi-source multi-purpose auxiliary steam system according to claim 1, characterized in that, The auxiliary boiler has three operating conditions: normal operation, hot standby, and cold standby; Normal operation refers to any operating condition between the minimum flow rate of 0.5 t / h and the rated flow rate of 50 t / h; Cold standby refers to a standby operating condition in which the auxiliary boiler is filled with cold water. Hot standby refers to a standby operating condition in which the auxiliary boiler is kept in a hot state by means of an electric heater; The auxiliary boiler is kept in cold standby for a long time and has the ability to quickly and automatically switch from cold standby to normal operation manually. During the start-up and shutdown phases of a high-temperature gas-cooled reactor unit, if the main steam cannot meet the steam requirements for auxiliary steam, the auxiliary boiler will be put into operation.

10. The high-temperature gas-cooled reactor multi-steam-source multi-purpose auxiliary steam system according to claim 9, characterized in that, The heating system uses the main steam from the steam generator to heat the demineralized water to produce external steam, including superheaters at various stages, low-pressure evaporators, and preheaters; When the auxiliary boiler is in cold standby or the reactor is in emergency shutdown condition, the auxiliary steam system uses the waste heat from the low-pressure evaporator of the heating system to flash as turbine shaft seal steam.

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