A primary circuit hot test system and method for a high-temperature gas-cooled reactor nuclear power plant

Abstract

The present invention discloses a primary circuit hot test system and method for a high-temperature gas-cooled reactor nuclear power plant. The system and method include graphite and carbon brick internals, a reactor pebble bed core, a reactor pressure vessel, a steam generator, a primary circuit concrete cabin, a first stop valve, a cabin ventilation device, a second stop valve, a vacuum pump, a third stop valve, a fourth stop valve, a fifth stop valve, an electric heater, a helium-helium cooler, a cryogenic adsorption bed, a helium compressor, a sixth stop valve, a helium-water cooler, a gas-water separator, and a seventh stop valve. The system and method can accelerate the helium heating rate during the primary circuit hot test, improve the heating and dehumidification efficiency, shorten the hot test time, and improve the hot test efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power, and relates to a primary circuit hot test system and method for a high-temperature gas-cooled reactor nuclear power plant. Background Art

[0002] The purpose of a nuclear power plant hot test is to verify that the system's thermal functions conform to design requirements under conditions that closely simulate actual plant operating conditions; verify the reliability of systems, equipment, and instrumentation at rated temperatures; and verify operating procedures and periodic testing procedures. Hot testing of a high-temperature gas-cooled reactor utilizes the operating power of the main helium blower to heat the primary circuit hot test area to 250°C and maintain thermal equilibrium. During the heating process, dehumidification of the primary circuit's graphite and carbon brick internals, which have high moisture content, is required to prevent moisture from being released into the high-temperature helium gas during reactor operation, potentially causing corrosion of primary circuit equipment, insulation degradation, and damage to lubricant coatings.

[0003] To prevent moisture released from graphite and carbon brick internals from condensing on primary circuit equipment and causing damage, the primary circuit heating and dehumidification mechanism requires that the released moisture be removed from the reactor within a specified timeframe (approximately 15 hours). Based on the power balance between the main helium blower power and the heat dissipation from the primary circuit hot test area in a high-temperature gas-cooled reactor (HTGR), the primary circuit helium can be heated from 20°C to approximately 150°C in 15 hours. However, the dehumidification effect at this temperature is limited. Given the limited heating power provided by the existing main helium blower, how to increase the heating temperature within the specified timeframe to enhance dehumidification and, therefore, improve hot test efficiency, has become a key technical challenge in primary circuit hot testing of HTGR nuclear power plants. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a primary loop hot test system and method for a high-temperature gas-cooled reactor nuclear power plant. The system and method can accelerate the helium heating rate during the primary loop hot test, improve the heating and dehumidification efficiency, shorten the hot test time, and improve the hot test efficiency.

[0005] To achieve the above-mentioned object, the primary loop hot test system of the high-temperature gas-cooled reactor nuclear power plant described in the present invention includes graphite and carbon brick internals, a reactor pebble bed core, a reactor pressure vessel, a steam generator, a primary loop concrete cabin, a first stop valve, a cabin ventilation device, a second stop valve, a vacuum pump, a third stop valve, a fourth stop valve, a fifth stop valve, an electric heater, a helium-helium cooler, a cryogenic adsorption bed, a helium compressor, a sixth stop valve, a helium-water cooler, a gas-water separator, and a seventh stop valve;

[0006] The graphite and carbon brick internals and the reactor pebble bed core are located within the reactor pressure vessel, and the reactor pebble bed core is encased within the graphite and carbon brick internals. The reactor pressure vessel is connected to the steam generator via a hot gas duct. A main helium blower is disposed on top of the steam generator. The steam generator and the reactor pressure vessel together constitute a primary hot test area, which is located within a primary concrete compartment. The outlet of the primary concrete compartment is divided into two routes, one of which is connected to the compartment ventilation device via a first stop valve, and the other is connected to the inlet of a vacuum pump via a second stop valve. The outlet of the vacuum pump is connected to the compartment ventilation device, and the outlet of the steam generator is connected to the inlet of the vacuum pump via a third stop valve.

[0007] The inlet of the fourth stop valve is connected to the outlet of the steam generator. The outlet of the fourth stop valve is divided into two paths, one of which is connected to the inlet of the helium compressor via the fifth stop valve, the electric heater, the helium-helium cooler and the low-temperature adsorption bed, and the other is connected to the inlet of the helium compressor via the sixth stop valve, the helium-water cooler and the gas-water separator in sequence. The outlet of the helium compressor is connected to the inlet of the steam generator via the seventh stop valve.

[0008] A dust filter is provided between the fifth stop valve and the electric heater.

[0009] It also includes a helium storage tank and an eighth stop valve, wherein the outlet of the helium storage tank is connected to the inlet of the dust filter through the eighth stop valve.

[0010] The primary circuit hot test method of a high-temperature gas-cooled reactor nuclear power plant according to the present invention comprises three stages:

[0011] The first stage is the vacuuming stage of the primary circuit hot test area and the primary circuit concrete compartment:

[0012] The process of evacuating the primary loop hot test area is carried out according to process 1. The specific process of process 1 is as follows: closing the first stop valve, the second stop valve, the fourth stop valve and the seventh stop valve, opening the third stop valve, and starting the vacuum pump. The air in the reactor pebble bed core sequentially passes through the graphite and carbon brick internals, the reactor pressure vessel, the steam generator, the third stop valve and the vacuum pump and enters the cabin ventilation device. During this process, the vacuum degree in the reactor pressure vessel is measured by a vacuum gauge. When the vacuum degree in the reactor pressure vessel is ≤100Pa, the vacuum evacuation of the primary loop hot test area is completed.

[0013] The vacuuming of the primary-loop concrete cabin is carried out according to process 2. The specific process of process 2 is: close the third stop valve, open the second stop valve, start the vacuum pump, and the air in the primary-loop concrete cabin enters the cabin ventilation device through the second stop valve and the vacuum pump in sequence. During this process, when the vacuum degree in the primary-loop concrete cabin is ≤100Pa, the vacuuming of the primary-loop concrete cabin is completed.

[0014] The second stage is the helium filling stage of the primary circuit of the high-temperature gas-cooled reactor, which is specifically carried out in accordance with process 3. The specific process of process 3 is: closing the first stop valve, the second stop valve, the third stop valve, the fourth stop valve, the fifth stop valve and the sixth stop valve, opening the eighth stop valve and the seventh stop valve, starting the helium compressor, and using the helium compressor to provide power to increase the helium pressure to 7 MPa and the flow rate to 1.1 kg / s. The helium in the helium storage tank passes through the eighth stop valve, the dust filter, the electric heater, the helium-helium cooler, the cryogenic adsorption bed, the helium compressor, the seventh stop valve, the steam generator and the reactor pressure vessel in sequence and enters the reactor pebble bed core;

[0015] The third stage is the heating and dehumidification stage of the primary circuit of the high-temperature gas-cooled reactor, which is specifically carried out in accordance with process 4. The specific process of process 4 is: start the main helium blower, open the fourth stop valve, the sixth stop valve and the seventh stop valve, close the first stop valve, the second stop valve, the third stop valve and the fifth stop valve, and the 20°C cold helium in the steam generator is driven by the main helium blower through the fourth stop valve, the sixth stop valve, the helium-water cooler, the gas-water separator, the helium compressor and the seventh stop valve into the steam generator in sequence. During this process, the moisture in the graphite and carbon brick components of the stack is heated and precipitated, and is removed through the helium-water cooler and the gas-water separator until the helium temperature reaches 250°C, thereby completing the heating and dehumidification of the primary circuit of the high-temperature gas-cooled reactor.

[0016] During the hot test, the vacuum pump, helium storage tank, dust filter, electric heater, helium-helium cooler, cryogenic adsorption bed, sixth shut-off valve, helium-water cooler, gas-water separator and helium compressor are in standby mode. When the helium pressure, flow or purity in the primary circuit concrete compartment decreases, process 3 is executed; when the vacuum degree in the primary circuit concrete compartment decreases, process 2 is executed.

[0017] After the hot test is completed, close the second stop valve, stop the vacuum pump, open the first stop valve, and start the cabin ventilation device to restore the primary circuit concrete cabin to normal pressure.

[0018] The present invention has the following beneficial effects:

[0019] During specific operation, the primary circuit hot test system and method of a high-temperature gas-cooled reactor nuclear power plant described in the present invention can simultaneously perform vacuuming of the primary circuit concrete compartment and filling of the primary circuit with helium, without occupying critical path time during the hot test. The vacuum pump uses the primary circuit vacuuming system in the original hot test method, without additional equipment investment, and is practical. In addition, the primary circuit of the high-temperature gas-cooled reactor is heated and dehumidified simultaneously, that is, the 20°C cold helium in the steam generator is driven by the main helium fan through the fourth stop valve, the sixth stop valve, the helium-water cooler, the gas-water separator, the helium compressor and the seventh stop valve into the steam generator. During this process, the moisture in the graphite and carbon brick components of the reactor is precipitated during heating, and the moisture carried by the helium is removed by the helium-water cooler and the gas-water separator until the helium temperature reaches 250°C, so as to accelerate the helium heating rate during the primary circuit hot test and improve the heating and dehumidification efficiency. At the same time, it breaks through the limitation of the original dehumidification temperature of 150°C and improves the dehumidification effect. According to tests, the present invention only needs 15 hours to reach the target temperature. Compared with the existing 50 hours, the hot test time is shorter and the hot test efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] Among them, 1 is the reactor pebble bed core, 2 is the graphite and carbon brick internal components, 3 is the reactor pressure vessel, 4 is the steam generator, 5 is the main helium fan, 6 is the primary circuit concrete compartment, 7 is the first stop valve, 8 is the compartment ventilation device, 9 is the second stop valve, 10 is the vacuum pump, 11 is the third stop valve, 12 is the fourth stop valve, 13 is the fifth stop valve, 14 is the helium storage tank, 15 is the eighth stop valve, 16 is the dust filter, 17 is the electric heater, 18 is the helium-helium cooler, 19 is the low-temperature adsorption bed, 20 is the sixth stop valve, 21 is the helium-water cooler, 22 is the gas-water separator, 23 is the helium compressor, and 24 is the seventh stop valve. DETAILED DESCRIPTION

[0022] The present invention is described in further detail below with reference to the accompanying drawings:

[0023] refer to Figure 1The primary loop hot test system of a high-temperature gas-cooled reactor nuclear power plant of the present invention includes graphite and carbon brick internals 2, a reactor pebble bed core 1, a reactor pressure vessel 3, a steam generator 4, a primary loop concrete cabin 6, a first stop valve 7, a cabin ventilation device 8, a second stop valve 9, a vacuum pump 10, a third stop valve 11, a fourth stop valve 12, a fifth stop valve 13, an electric heater 17, a helium-helium cooler 18, a low-temperature adsorption bed 19, a helium compressor 23, a sixth stop valve 20, a helium-water cooler 21, a gas-water separator 22 and a seventh stop valve 24; the graphite and carbon brick internals 2 and the reactor pebble bed core 1 are located in the reactor pressure vessel 3, and the reactor pebble bed core 1 is wrapped in the graphite and carbon brick internals 2, the reactor pressure vessel 3 is connected to the steam generator 4 through a hot gas duct, a main helium blower 5 is arranged on the top of the steam generator 4, and the steam generator 4 and the reactor pressure vessel 3 together constitute a primary loop. Hot test area, the primary hot test area is located in the primary concrete cabin 6, the outlet of the primary concrete cabin 6 is divided into two routes, one of which is connected to the cabin ventilation device 8 through the first stop valve 7, and the other is connected to the inlet of the vacuum pump 10 through the second stop valve 9. The outlet of the vacuum pump 10 is connected to the cabin ventilation device 8, and the outlet of the steam generator 4 is connected to the inlet of the vacuum pump 10 through the third stop valve 11; the inlet of the fourth stop valve 12 is connected to the outlet of the steam generator 4, and the outlet of the fourth stop valve 12 is divided into two routes, one of which is connected to the inlet of the helium compressor 23 through the fifth stop valve 13, the electric heater 17, the helium-helium cooler 18 and the low-temperature adsorption bed 19, and the other is connected to the inlet of the helium compressor 23 through the sixth stop valve 20, the helium-water cooler 21 and the gas-water separator 22 in sequence, and the outlet of the helium compressor 23 is connected to the inlet of the steam generator 4 through the seventh stop valve 24.

[0024] A dust filter 16 is provided between the fifth stop valve 13 and the electric heater 17 . The present invention further includes a helium storage tank and an eighth stop valve 15 , wherein the outlet of the helium storage tank is connected to the inlet of the dust filter 16 via the eighth stop valve 15 .

[0025] The specific working process of the primary circuit hot test method of the high-temperature gas-cooled reactor nuclear power plant described in the present invention is as follows:

[0026] The first stage is the vacuuming of the primary circuit hot test area and the primary circuit concrete compartment 6:

[0027] This process mainly involves evacuating the primary circuit hot test area and the primary circuit concrete compartment 6, in preparation for filling the primary circuit concrete compartment 6 with high-purity helium in the second stage.

[0028] The vacuuming process of the primary circuit hot test area is carried out according to process 1. The specific process of process 1 is as follows: the first stop valve 7, the second stop valve 9, the fourth stop valve 12 and the seventh stop valve 24 are closed, the third stop valve 11 is opened, and the vacuum pump 10 is turned on. The air in the reactor pebble bed core 1 enters the cabin ventilation device 8 through the graphite and carbon brick internals 2, the reactor pressure vessel 3, the steam generator 4, the third stop valve 11 and the vacuum pump 10 in sequence. During this process, the vacuum degree in the reactor pressure vessel 3 is measured by a vacuum meter. When the vacuum degree in the reactor pressure vessel 3 is ≤100Pa, the vacuuming of the primary circuit hot test area is completed.

[0029] The vacuuming of the primary-loop concrete cabin 6 is carried out according to process 2. The specific process of process 2 is: close the third stop valve 11, open the second stop valve 9, start the vacuum pump 10, and the air in the primary-loop concrete cabin 6 enters the cabin ventilation device 8 through the second stop valve 9 and the vacuum pump 10 in sequence. During this process, when the vacuum degree in the primary-loop concrete cabin 6 is ≤100Pa, the vacuuming of the primary-loop concrete cabin 6 is completed.

[0030] The second stage is the helium filling stage of the primary circuit of the high-temperature gas-cooled reactor, which is carried out according to process 3;

[0031] The specific process of process 3 is as follows: closing the first stop valve 7, the second stop valve 9, the third stop valve 11, the fourth stop valve 12, the fifth stop valve 13 and the sixth stop valve 20, opening the eighth stop valve 15 and the seventh stop valve 24, and starting the helium compressor 23. The helium compressor 23 provides power to increase the helium pressure to 7 MPa and the flow rate to 1.1 kg / s. The helium in the helium storage tank 14 enters the reactor pebble bed core 1 through the eighth stop valve 15, the dust filter 16, the electric heater 17, the helium-helium cooler 18, the cryogenic adsorption bed 19, the helium compressor 23, the seventh stop valve 24, the steam generator 4 and the reactor pressure vessel 3 in sequence;

[0032] As the heating rate of the cold helium gas increases, the helium pressure rises correspondingly faster during the helium filling stage of the primary circuit, which is beneficial for the helium purification system such as the dust filter 16, the electric heater 17, and the low-temperature adsorption bed 19 to achieve high-flow operation, thereby improving the equipment operation reliability and helium purification efficiency.

[0033] The third stage is the heating and dehumidification stage of the primary circuit of the high-temperature gas-cooled reactor, and the heating and dehumidification are carried out according to process 4;

[0034] The specific process of process 4 is as follows: start the main helium blower 5, open the fourth stop valve 12, the sixth stop valve 20 and the seventh stop valve 24, close the first stop valve 7, the second stop valve 9, the third stop valve 11 and the fifth stop valve 13, and the 20°C cold helium in the steam generator 4 is driven by the main helium blower 5 in sequence through the fourth stop valve 12, the sixth stop valve 20, the helium-water cooler 21, the gas-water separator 22, the helium compressor 23 and the seventh stop valve 24 into the steam generator 4. During this process, the moisture in the graphite and carbon brick stack internal components 2 is precipitated by heating, and the moisture carried by the helium is removed by the helium-water cooler 21 and the gas-water separator 22 until the helium temperature reaches 250°C, achieving the best dehumidification effect.

[0035] During the hot test, the vacuum pump 10, helium storage tank 14, dust filter 16, electric heater 17, helium-helium cooler 18, cryogenic adsorption bed 19, sixth shut-off valve 20, helium-water cooler 21, gas-water separator 22, and helium compressor 23 are in standby mode. When the helium pressure, flow rate, or purity in the primary-loop concrete compartment 6 decreases, process 3 is executed; when the vacuum level in the primary-loop concrete compartment 6 decreases, process 2 is executed.

[0036] After the hot test is completed, the second stop valve 9 is closed, the vacuum pump 10 is stopped, the first stop valve 7 is opened, and the cabin ventilation device 8 is put into operation to restore the primary circuit concrete cabin 6 to a normal pressure state.

[0037] The present invention realizes the simultaneous implementation of thermal testing and heating and dehumidification. Preliminary calculations show that the heating power of the main helium blower 5 is 4500KW. The present invention shortens the thermal testing heating time by about 35 hours and the heating and dehumidification time by 27 days. It is calculated that the economic cost can be directly saved by about 22.25 million yuan, which has substantial economic benefits.

Claims

1. A primary circuit hot test system for a high temperature gas-cooled reactor nuclear power plant, characterized in that: The invention comprises graphite and carbon brick internal components (2), a reactor pebble bed core (1), a reactor pressure vessel (3), a steam generator (4), a primary circuit concrete compartment (6), a first stop valve (7), a compartment ventilation device (8), a second stop valve (9), a vacuum pump (10), a third stop valve (11), a fourth stop valve (12), a fifth stop valve (13), an electric heater (17), a helium-helium cooler (18), a cryogenic adsorption bed (19), a helium compressor (23), a sixth stop valve (20), a helium-water cooler (21), a gas-water separator (22) and a seventh stop valve (24); The graphite and carbon brick internals (2) and the reactor pebble bed core (1) are located in a reactor pressure vessel (3), and the reactor pebble bed core (1) is wrapped in the graphite and carbon brick internals (2). The reactor pressure vessel (3) is connected to the steam generator (4) through a hot gas conduit. A main helium blower (5) is arranged on the top of the steam generator (4). The steam generator (4) and the reactor pressure vessel (3) together constitute a primary circuit hot test area. The primary circuit hot test area is located in a primary circuit concrete cabin (6). The outlet of the primary circuit concrete cabin (6) is divided into two paths, one of which is connected to the cabin ventilation device (8) through a first stop valve (7), and the other is connected to the inlet of a vacuum pump (10) through a second stop valve (9). The outlet of the vacuum pump (10) is connected to the cabin ventilation device (8), and the outlet of the steam generator (4) is connected to the inlet of the vacuum pump (10) through a third stop valve (11); The inlet of the fourth stop valve (12) is connected to the outlet of the steam generator (4). The outlet of the fourth stop valve (12) is divided into two paths, one of which is connected to the inlet of the helium compressor (23) via the fifth stop valve (13), the electric heater (17), the helium-helium cooler (18) and the low-temperature adsorption bed (19), and the other is connected to the inlet of the helium compressor (23) via the sixth stop valve (20), the helium-water cooler (21) and the gas-water separator (22). The outlet of the helium compressor (23) is connected to the inlet of the steam generator (4) via the seventh stop valve (24).

2. The primary circuit hot test system of a high temperature gas-cooled reactor nuclear power plant according to claim 1, characterized in that: A dust filter (16) is provided between the fifth stop valve (13) and the electric heater (17).

3. The primary circuit hot test system of a high temperature gas-cooled reactor nuclear power plant according to claim 2, characterized in that: It also includes a helium storage tank and an eighth stop valve (15), wherein the outlet of the helium storage tank is connected to the inlet of the dust filter (16) through the eighth stop valve (15).

4. A primary circuit hot test method for a high-temperature gas-cooled reactor nuclear power plant, characterized in that: The primary circuit hot test system of a high temperature gas-cooled reactor nuclear power plant according to claim 3 comprises three stages; The first stage is the vacuuming stage of the primary circuit hot test area and the primary circuit concrete compartment (6): The process of evacuating the primary circuit hot test area is carried out according to process 1. The specific process of process 1 is as follows: closing the first stop valve (7), the second stop valve (9), the fourth stop valve (12) and the seventh stop valve (24), opening the third stop valve (11), and starting the vacuum pump (10). The air in the reactor pebble bed core (1) enters the cabin ventilation device (8) in sequence through the graphite and carbon brick internal components (2), the reactor pressure vessel (3), the steam generator (4), the third stop valve (11) and the vacuum pump (10). During this process, the vacuum degree in the reactor pressure vessel (3) is measured by a vacuum meter. When the vacuum degree in the reactor pressure vessel (3) is ≤100 Pa, the evacuation of the primary circuit hot test area is completed. The vacuuming of the primary circuit concrete cabin (6) is carried out according to process 2. The specific process of process 2 is as follows: closing the third stop valve (11), opening the second stop valve (9), and starting the vacuum pump (10). The air in the primary circuit concrete cabin (6) enters the cabin ventilation device (8) through the second stop valve (9) and the vacuum pump (10) in sequence. During this process, when the vacuum degree in the primary circuit concrete cabin (6) is ≤100 Pa, the vacuuming of the primary circuit concrete cabin (6) is completed. The second stage is the helium filling stage of the high-temperature gas-cooled reactor primary circuit, which is specifically carried out according to process 3, wherein the specific process of process 3 is: closing the first stop valve (7), the second stop valve (9), the third stop valve (11), the fourth stop valve (12), the fifth stop valve (13) and the sixth stop valve (20), opening the eighth stop valve (15) and the seventh stop valve (24), starting the helium compressor (23), and using the helium compressor (23) to provide power to increase the helium pressure to 7 MPa and the flow rate to 1.1 kg / s. The helium in the helium storage tank (14) sequentially passes through the eighth stop valve (15), the dust filter (16), the electric heater (17), the helium-helium cooler (18), the low-temperature adsorption bed (19), the helium compressor (23), the seventh stop valve (24), the steam generator (4) and the reactor pressure vessel (3) into the reactor pebble bed core (1); The third stage is the heating and dehumidification stage of the primary circuit of the high-temperature gas-cooled reactor, which is specifically carried out according to process 4, wherein the specific process of process 4 is: starting the main helium blower (5), opening the fourth stop valve (12), the sixth stop valve (20) and the seventh stop valve (24), closing the first stop valve (7), the second stop valve (9), the third stop valve (11) and the fifth stop valve (13), and driving the main helium blower (5) to sequentially pass through the fourth stop valve (12), the sixth stop valve (20), the helium-water cooler (21), the gas-water separator (22), the helium compressor (23) and the seventh stop valve (24) into the steam generator (4). In this process, the moisture in the graphite and carbon brick internal components (2) is heated and precipitated, and is removed through the helium-water cooler (21) and the gas-water separator (22) until the helium temperature reaches 250°C, thereby completing the heating and dehumidification of the primary circuit of the high-temperature gas-cooled reactor.

5. The primary circuit hot test method of a high temperature gas-cooled reactor nuclear power plant according to claim 4, characterized in that: During the hot test, the vacuum pump (10), the helium storage tank (14), the dust filter (16), the electric heater (17), the helium-helium cooler (18), the low-temperature adsorption bed (19), the sixth stop valve (20), the helium-water cooler (21), the gas-water separator (22) and the helium compressor (23) are in a standby state. When the helium pressure, flow rate or purity in the primary circuit concrete chamber (6) decreases, process 3 is executed; when the vacuum degree in the primary circuit concrete chamber (6) decreases, process 2 is executed.

6. The primary circuit hot test method of a high temperature gas-cooled reactor nuclear power plant according to claim 5, characterized in that: After the hot test is completed, the second stop valve (9) is closed, the vacuum pump (10) is stopped, the first stop valve (7) is opened, and the cabin ventilation device (8) is put into operation to restore the primary circuit concrete cabin (6) to a normal pressure state.

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