System and method for typical operating conditions of a high temperature gas cooled reactor steam generator

Abstract

The application discloses a system and method for typical operation conditions of a high-temperature gas cooled reactor steam generator, wherein the outlet of a feedwater header is connected with the inlet of a feedwater pump, the outlet of the feedwater pump is divided into two paths, one of which is connected with the inlet of a fourth valve group, and the other is connected with the inlet of a water treatment device through a sixth valve group, the outlet of the water treatment device is divided into two paths after passing through a purified water delivery pump, one of which is connected with the inlet of the feedwater header through a seventh valve group, and the other is connected with the inlet of a makeup water tank through an eighth valve group, the outlet of the makeup water tank is connected with the tube side inlet of the steam generator through a makeup water pump, the outlet of the fourth valve group is divided into two paths, one of which is connected with the inlet of a discharge liquid recovery device through a fifth valve group, and the other is connected with the tube side inlet of the steam generator, and the system and method can ensure the safety and stability of a reactor core.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power safety facilities technology, and relates to a system and method for typical operating conditions of a high-temperature gas-cooled reactor steam generator. Background Technology

[0002] The high-temperature gas-cooled reactor (HTGR) steam generator is a vertical, direct-flow spiral tube type, offering advantages such as compact structure, high heat exchange efficiency, and easy integrated layout. However, it also exhibits unstable two-phase flow and complex, variable boiling heat transfer characteristics, requiring significantly higher steam quality than pressurized water reactors (PWRs) during operation. Furthermore, because the pressure in the secondary loop of the HTGR is much higher than in the primary loop, leaks or ruptures in the steam generator's heat transfer tubes can cause the steam-water mixture within the generator to be ejected into the primary loop under high pressure on the secondary side, flowing through the reactor core with the helium gas. Increased steam concentration in the pebble bed alters the neutron moderation or absorption effects in the core, thus changing its reactivity. The steam entering the core can also react with graphite under high-temperature conditions, producing water gas, which severely impacts the core's safety and stability. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for typical operating conditions of a high-temperature gas-cooled reactor steam generator, which can ensure the safety and stability of the reactor core.

[0004] To achieve the above objectives, the present invention discloses a system for typical operating conditions of a high-temperature gas-cooled reactor steam generator, including a steam generator, a main steam manifold, an exhaust chimney, a feedwater manifold, a feedwater pump, a fourth valve group, a water treatment device, a makeup water tank, and an exhaust liquid recovery device.

[0005] The steam generator has three outlets on its pipe side. One outlet is connected to the inlet of the main steam manifold via the first valve group. The second outlet is connected to the exhaust chimney via the second valve group and the iodine removal and purification device. The third outlet is connected to the exhaust chimney via the third valve group.

[0006] The outlet of the water supply manifold is connected to the inlet of the water supply pump. The outlet of the water supply pump is divided into two paths: one path is connected to the inlet of the fourth valve group, and the other path is connected to the inlet of the water treatment device via the sixth valve group. The outlet of the water treatment device is divided into two paths after passing through the purified water transfer pump: one path is connected to the inlet of the water supply manifold via the seventh valve group, and the other path is connected to the inlet of the makeup water tank via the eighth valve group. The outlet of the makeup water tank is connected to the pipe-side inlet of the steam generator via the makeup water pump. The outlet of the fourth valve group is divided into two paths: one path is connected to the inlet of the effluent recovery device via the fifth valve group, and the other path is connected to the pipe-side inlet of the steam generator.

[0007] It also includes a reactor and a main helium blower. The reactor outlet is connected to the shell-side inlet of the steam generator, the steam generator shell-side outlet is connected to the inlet of the main helium blower, and the main helium blower outlet is connected to the reactor inlet.

[0008] It also includes a water supply monitoring device, which is connected to the pipeline between the outlet of the water supply pump and the fourth valve group.

[0009] It also includes a humidity monitor, which is connected to the pipeline between the reactor outlet and the steam generator inlet.

[0010] The first valve group, the second valve group, the fourth valve group, the fifth valve group, the sixth valve group, the seventh valve group, and the eighth valve group are all composed of isolation valves and regulating valves;

[0011] The third valve assembly is a spring-loaded safety valve assembly.

[0012] The method for typical operating conditions of a high-temperature gas-cooled reactor steam generator as described in this invention includes normal unit operation, purification circuit activation operation, overpressure protection operation, and emergency discharge operation.

[0013] Under normal operating conditions, the unit includes the following steps:

[0014] 1) The reactor starts normally. The main helium blower is started. Cold helium gas is delivered to the reactor core through the main helium blower to absorb heat and become hot helium gas. The hot helium gas enters the shell side of the steam generator and exchanges heat with the feedwater on the pipe side to become cold helium gas. The cold helium gas continues to be delivered to the reactor core to absorb heat to form a reactor circulation loop.

[0015] 2) Start the feedwater pump. The feedwater output from the feedwater manifold is pumped to the tube side of the steam generator. After absorbing the heat of the hot helium gas in the steam generator, the generated steam enters the main steam manifold. The feedwater quality at the tube side inlet of the steam generator is monitored online in real time by the feedwater monitor, and the humidity on the shell side of the steam generator is monitored online in real time by the humidity monitor to ensure that the parameters of the steam generator are normal during operation, the reactor reaches full power operation, and the steam generator operates at full load.

[0016] When the purification circuit is put into operation, the following steps are included:

[0017] 1) When the humidity monitor shows normal but the feedwater monitor shows abnormal, the reactor operates at reduced power, the fourth valve group is closed, and the makeup water pump is started. The makeup water pump delivers the feedwater in the makeup water tank to the tube side of the steam generator to ensure a stable feedwater flow rate to the steam generator.

[0018] 2) When the sixth and seventh valve groups are opened, the purified water delivery pump starts. The water output from the water supply manifold is purified by the water treatment device and then delivered to the water supply manifold by the purified water delivery pump to form a purification loop.

[0019] 3) After the feedwater monitor shows normal operation, close the sixth valve group, stop the purified water delivery pump, open the fourth and eighth valve groups, and when the steam generator feedwater flow rate is stable, stop the makeup water pump, restore the unit to normal operating conditions, increase the reactor power to the initial operating state, replenish the makeup water tank to the normal liquid level, and then close the eighth valve group.

[0020] Under overpressure protection operating conditions, the following steps are included:

[0021] When the pressure in the main steam manifold exceeds the design pressure, the third valve group will open to release the main steam to the exhaust chimney. When the pressure in the main steam manifold drops back to the normal operating pressure, the third valve group will close, restoring the unit to normal operating conditions.

[0022] Under accident emission operating conditions, the following steps are included:

[0023] When the humidity monitor shows an abnormality, the reactor power is reduced to shutdown, the main helium blower stops operating, the fourth valve group is closed, the second and fifth valve groups are opened, the steam-water mixture in the steam generator is passively discharged, the radioactive feedwater is discharged to the effluent recovery device, and the radioactive steam is discharged to the iodine removal purification device, and after filtration, it is discharged to the emission chimney.

[0024] The present invention has the following beneficial effects:

[0025] In specific operation, the system and method for the typical operating conditions of the high-temperature gas-cooled reactor steam generator described in this invention monitors the feedwater quality of the secondary loop. When the feedwater quality of the steam generator is abnormal, it promptly switches to the purification loop while maintaining a stable feedwater flow rate through a replenishment tank. By monitoring the helium humidity of the primary loop, it promptly switches to the emergency discharge loop in case of a ruptured heat transfer tube in the steam generator, preventing water ingress into the reactor core and safely recovering radioactive steam-water mixture from the steam generator. When the main steam pressure is high, it promptly switches to the overpressure protection loop to release pressure to the normal operating pressure, ensuring the safe and stable operation of the unit.

[0026] Furthermore, in this invention, the various operating circuits of the steam generator are isolated and switched through valve groups, which has the advantages of independent operating conditions and fast switching process, and the system has high reliability. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention.

[0028] Among them, 1 is the reactor, 2 is the steam generator, 3 is the main helium blower, 4 is the first valve group, 5 is the main steam manifold, 6 is the second valve group, 7 is the iodine removal and purification device, 8 is the exhaust chimney, 9 is the third valve group, 10 is the water supply manifold, 11 is the water supply pump, 12 is the fourth valve group, 13 is the fifth valve group, 14 is the effluent recovery device, 15 is the sixth valve group, 16 is the water treatment device, 17 is the purified water transfer pump, 18 is the seventh valve group, 19 is the eighth valve group, 20 is the makeup water tank, 21 is the makeup water pump, 22 is the water supply monitoring instrument, and 23 is the humidity monitoring instrument. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0030] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0031] refer to Figure 1 The system of the high-temperature gas-cooled reactor steam generator under typical operating conditions described in this invention includes a reactor 1, a steam generator 2, a main helium blower 3, a first valve group 4, a main steam manifold 5, a second valve group 6, an iodine removal and purification device 7, an exhaust chimney 8, a third valve group 9, a feedwater manifold 10, a feedwater pump 11, a fourth valve group 12, a fifth valve group 13, an exhaust liquid recovery device 14, a sixth valve group 15, a water treatment device 16, a purified water delivery pump 17, a seventh valve group 18, an eighth valve group 19, a makeup water tank 20, a makeup water pump 21, a feedwater monitoring instrument 22, and a humidity monitoring instrument 23.

[0032] The outlet of reactor 1 is connected to the shell-side inlet of steam generator 2, the shell-side outlet of steam generator 2 is connected to the inlet of main helium blower 3, and the outlet of main helium blower 3 is connected to the inlet of reactor 1.

[0033] The pipe-side outlet of the steam generator 2 is divided into three paths. One path is connected to the inlet of the main steam manifold 5 via the first valve group 4. The first path is connected to the exhaust chimney 8 via the second valve group 6 and the iodine removal and purification device 7. The third path is connected to the exhaust chimney 8 via the third valve group 9.

[0034] The outlet of the water supply manifold 10 is connected to the inlet of the water supply pump 11. The outlet of the water supply pump 11 is divided into two paths: one path is connected to the inlet of the fourth valve group 12, and the other path is connected to the inlet of the water treatment device 16 via the sixth valve group 15. The outlet of the water treatment device 16 is connected to the inlet of the purified water transfer pump 17. The outlet of the purified water transfer pump 17 is divided into two paths: one path is connected to the inlet of the water supply manifold 10 via the seventh valve group 18, and the other path is connected to the inlet of the makeup water tank 20 via the eighth valve group 19. The outlet of the makeup water tank 20 is connected to the pipe-side inlet of the steam generator 2 via the makeup water pump 21. The outlet of the fourth valve group 12 is divided into two paths: one path is connected to the inlet of the discharge liquid recovery device 14 via the fifth valve group 13, and the other path is connected to the pipe-side inlet of the steam generator 2.

[0035] Among them, the first valve group 4, the second valve group 6, the fourth valve group 12, the fifth valve group 13, the sixth valve group 15, the seventh valve group 18 and the eighth valve group 19 are all composed of isolation valves and regulating valves; the third valve group 9 is a spring-loaded safety valve group.

[0036] The water supply monitor 22 is connected to the pipeline between the outlet of the water supply pump 11 and the fourth valve group 12, and the humidity monitor 23 is connected to the pipeline between the outlet of the reactor 1 and the inlet of the steam generator 2.

[0037] refer to Figure 1 The method for typical operating conditions of a high-temperature gas-cooled reactor steam generator according to the present invention includes the following steps:

[0038] Initial system status: Reactor 1, main helium blower 3, feedwater pump 11, purified water transfer pump 17 and makeup water pump 21 are not running; valve group 4 and valve group 12 are open; valve group 6, valve group 9, valve group 13, valve group 15, valve group 18 and valve group 19 are closed.

[0039] 1. Normal operating conditions of the unit:

[0040] 1) Reactor 1 starts normally. The main helium blower 3 is started. Cold helium gas is delivered to the core of reactor 1 through the main helium blower 3 to absorb heat and become hot helium gas. The hot helium gas enters the shell side of steam generator 2 and exchanges heat with the feedwater on the pipe side to become cold helium gas. The cold helium gas continues to be delivered to the core of reactor 1 to absorb heat, so as to form a circulation loop of reactor 1.

[0041] 2) Start the feedwater pump 11. The feedwater output from the feedwater manifold 10 is delivered to the pipe side of the steam generator 2 via the feedwater pump 11. After absorbing the heat of the hot helium gas in the steam generator 2, the generated steam enters the main steam manifold 5. The feedwater quality at the pipe side inlet of the steam generator 2 is monitored online in real time by the feedwater monitor 22, and the humidity on the shell side of the steam generator 2 is monitored online in real time by the humidity monitor 23 to ensure that the parameters of the steam generator 2 are normal during operation, the reactor 1 is running at full power, and the steam generator 2 is running at full load.

[0042] 2. Operating conditions of the purification circuit:

[0043] 1) When the humidity monitor 23 shows normal and the feedwater monitor 22 shows abnormal, the reactor 1 operates at reduced power, the fourth valve group 12 is closed, and the makeup water pump 21 is started. The makeup water pump 21 delivers the feedwater in the makeup water tank 20 to the pipe side of the steam generator 2 to ensure the stable feedwater flow of the steam generator 2.

[0044] 2) When the sixth valve group 15 and the seventh valve group 18 are opened, the purified water delivery pump 17 is started. The water output from the water supply manifold 10 is purified by the water treatment device 16 and then delivered to the water supply manifold 10 by the purified water delivery pump 17 to form a purification circuit.

[0045] 3) After the feedwater monitor 22 shows normal operation, close the sixth valve group 15, stop the purified water transfer pump 17, open the fourth valve group 12 and the eighth valve group 19. When the feedwater flow of the steam generator 2 is stable, stop the makeup water pump 21 and restore the unit to normal operating conditions. The reactor 1 power is increased to the initial operating state. After the makeup water tank 20 is filled to the normal liquid level, close the eighth valve group 19.

[0046] 3. Overpressure protection operating conditions:

[0047] When the pressure in the main steam manifold 5 exceeds the design pressure, the third valve group 9 will be opened to release the main steam to the exhaust chimney 8. When the pressure in the main steam manifold 5 drops back to the normal operating pressure, the third valve group 9 will be closed by the spring force, restoring the unit to normal operating conditions.

[0048] 4. Operating conditions for accident emissions:

[0049] When the humidity monitor 23 shows an abnormality, the reactor 1 reduces its power to shutdown, the main helium blower 3 stops operating, the fourth valve group 12 closes, the second valve group 6 and the fifth valve group 13 open, the steam-water mixture in the steam generator 2 is passively discharged, the radioactive feedwater is discharged to the discharge liquid recovery device 14, and the radioactive steam is discharged to the iodine removal purification device 7, and after filtration, it is discharged to the emission chimney 8.

[0050] Example 1

[0051] This embodiment takes a high-temperature gas-cooled reactor nuclear power unit as an example. The steam generator 2 of the high-temperature gas-cooled reactor nuclear power unit is a vertical, DC helical tube assembly structure. Each 200MW high-temperature gas-cooled reactor nuclear power unit has two steam generators 2. The tube bundle of the steam generator 2 contains a steam-water mixture from the secondary loop, and the outer shell side contains helium from the primary loop of reactor 1. The operating pressure is 7MPa; the operating pressure of the secondary loop is 13.9MPa, and the design pressure is 14.2MPa. The primary loop operates normally with a humidity less than 30℃ dew point (pressure 7MPa). The feedwater quality standards for the steam generator 2 during unit operation are shown in Table 1 below.

[0052] Table 1

[0053]

[0054] Initial system status: Reactor 1, main helium blower 3, feedwater pump 11, purified water transfer pump 17 and makeup water pump 21 are not running; valve group 4 and valve group 12 are open; valve group 6, valve group 9, valve group 13, valve group 15, valve group 18 and valve group 19 are closed.

[0055] 1. Normal operating conditions of the unit:

[0056] 1) Reactor 1 starts normally, the main helium blower 3 starts and delivers cold helium to the reactor core of reactor 1 to absorb heat and become hot helium. The hot helium enters the shell side of steam generator 2 and exchanges heat with the feedwater on the tube side to become cold helium. The cold helium continues to be delivered to the reactor core of reactor 1 to absorb heat and form a reactor 1 circulation loop.

[0057] 2) Start the feedwater pump 11. The feedwater output from the feedwater manifold 10 is pumped to the pipe side of the steam generator 2 via the feedwater pump 11. After absorbing heat from the hot helium gas in the steam generator 2, steam is generated and enters the main steam manifold 5. The feedwater quality at the pipe side inlet of the steam generator 2 is monitored online in real time by the feedwater monitoring instrument 22. During unit operation, the feedwater quality of the steam generator 2 meets the operating value requirements in Table 1, namely: hydrogen conductivity (25℃) ≤ 0.08μS / cm, dissolved oxygen ≤ 1μg / L, hydrazine 30~50μg / L, chlorine Ions ≤0.5μg / L, sulfate ions ≤0.5μg / L, iron ≤3μg / L, copper ≤1μg / L, sodium ≤1μg / L, silica (dissolved silica) ≤5μg / L. The humidity on the shell side of steam generator 2 is monitored online in real time by humidity monitor 23 to ensure that the dew point (pressure of 7MPa) at 30℃ is monitored to ensure that the parameters of steam generator 2 are normal during operation. The primary loop helium pressure is 7MPa, the main steam pressure is 13.9MPa, reactor 1 is running at full power, and steam generator 2 is running at full load.

[0058] 2. Operating conditions of the purification circuit:

[0059] 1) When the humidity monitor 23 displays normal readings and the feedwater monitor 22 monitors the feedwater quality in real time, if any of the following indicators reach the alarm value: hydrogen conductivity (25℃) > 0.10 μS / cm, dissolved oxygen > 3 μg / L, hydrazine > 100 μg / L, chloride ion > 1 μg / L, sulfate ion > 1 μg / L, iron > 5 μg / L, copper > 2 μg / L, sodium > 2 μg / L, or silica (dissolved silica) > 10 μg / L, the feedwater parameters are considered substandard. Reactor 1 operates at reduced power, the fourth valve group 12 is quickly closed, the makeup water pump 21 is started, and feedwater from the makeup water tank 20 is delivered to the pipe side of the steam generator 2 to ensure a stable feedwater flow rate for the steam generator 2.

[0060] 2) When the sixth valve group 15 and the seventh valve group 18 are opened, the purified water delivery pump 17 is started. The water output from the water supply manifold 10 is purified by the water treatment device 16 and then delivered to the water supply manifold 10 by the purified water delivery pump 17, forming a purification circuit.

[0061] 3) Through the above-mentioned cycle purification, the feedwater quality of the steam generator 2 meets the operating value requirements in Table 1 during unit operation. After confirming that the feedwater monitoring instrument 22 is normal, close the sixth valve group 15, stop the purified water transfer pump 17, open the fourth valve group 12, and after the feedwater flow of the steam generator 2 is stable, stop the makeup water pump 21 and restore the unit to normal operating conditions. The reactor 1 power is increased to the initial operating state. After the makeup water tank 20 is filled to the normal liquid level, close the eighth valve group 19.

[0062] 3. Overpressure protection operating conditions:

[0063] When the main steam pressure is ≥14.2MPa, the third valve group 9 opens quickly to release the main steam to the exhaust chimney 8. When the main steam pressure drops back to the normal operating pressure of 13.9MPa, the third valve group 9 closes by the action of the spring force, restoring the unit to normal operating conditions.

[0064] 4. Operating conditions for accident emissions:

[0065] When the humidity monitor 23 reaches the alarm value, i.e., the humidity on the shell side of the steam generator 2 is greater than the 35°C dew point (pressure 7MPa), the reactor 1 reduces its power to shutdown, and the main helium blower 3 stops operating. The fourth valve group 12 closes rapidly, and the second valve group 6 and the fifth valve group 13 open rapidly. The steam-water mixture in the steam generator 2 is rapidly and passively discharged. The radioactive feedwater is discharged to the effluent recovery device 14, and the radioactive steam is discharged to the iodine removal and purification device 7. After filtration, it is discharged to the exhaust chimney 8.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A system for typical operating conditions of a high-temperature gas-cooled reactor steam generator, characterized in that, It includes a steam generator (2), a main steam manifold (5), an exhaust chimney (8), a water supply manifold (10), a water supply pump (11), a fourth valve group (12), a water treatment device (16), a make-up water tank (20), and an exhaust liquid recovery device (14). The pipe-side outlet of the steam generator (2) is divided into three paths. One path is connected to the inlet of the main steam manifold (5) via the first valve group (4), the second path is connected to the exhaust chimney (8) via the second valve group (6) and the iodine removal and purification device (7), and the third path is connected to the exhaust chimney (8) via the third valve group (9). The outlet of the water supply manifold (10) is connected to the inlet of the water supply pump (11). The outlet of the water supply pump (11) is divided into two paths. One path is connected to the inlet of the fourth valve group (12), and the other path is connected to the inlet of the water treatment device (16) via the sixth valve group (15). The outlet of the water treatment device (16) is divided into two paths after passing through the purified water transfer pump (17). One path is connected to the inlet of the water supply manifold (10) via the seventh valve group (18), and the other path is connected to the inlet of the makeup water tank (20) via the eighth valve group (19). The outlet of the makeup water tank (20) is connected to the pipe-side inlet of the steam generator (2) via the makeup water pump (21). The outlet of the fourth valve group (12) is divided into two paths. One path is connected to the inlet of the discharge liquid recovery device (14) via the fifth valve group (13), and the other path is connected to the pipe-side inlet of the steam generator (2).

2. The system for typical operating conditions of a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, It also includes a reactor (1) and a main helium blower (3). The outlet of the reactor (1) is connected to the shell-side inlet of the steam generator (2). The shell-side outlet of the steam generator (2) is connected to the inlet of the main helium blower (3). The outlet of the main helium blower (3) is connected to the inlet of the reactor (1).

3. The system for typical operating conditions of a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, It also includes a water supply monitoring device (22), which is installed on the pipeline between the outlet of the water supply pump (11) and the fourth valve group (12).

4. The system for typical operating conditions of a high-temperature gas-cooled reactor steam generator according to claim 3, characterized in that, It also includes a humidity monitor (23), which is installed on the pipe between the outlet of the reactor (1) and the inlet of the steam generator (2).

5. The system for typical operating conditions of a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The first valve group (4), the second valve group (6), the fourth valve group (12), the fifth valve group (13), the sixth valve group (15), the seventh valve group (18), and the eighth valve group (19) are all composed of isolation valves and regulating valves; The third valve group (9) is a spring-loaded safety valve group.

6. A method for typical operating conditions of a high-temperature gas-cooled reactor steam generator, characterized in that, The system based on the typical operating conditions of the high-temperature gas-cooled reactor steam generator as described in claim 4 includes normal unit operation, purification circuit operation, overpressure protection operation, and emergency discharge operation. Under normal operating conditions, the unit includes the following steps: 1) The reactor (1) starts normally and the main helium blower (3) is started. Cold helium gas is transported to the core of the reactor (1) through the main helium blower (3) to absorb heat and become hot helium gas. The hot helium gas enters the shell side of the steam generator (2) and exchanges heat with the feedwater on the pipe side to become cold helium gas. The cold helium gas continues to be transported to the core of the reactor (1) to absorb heat in order to form a circulation loop of the reactor (1). 2) Start the feedwater pump (11). The feedwater output from the feedwater manifold (10) is pumped to the pipe side of the steam generator (2) by the feedwater pump (11). After absorbing the heat of the hot helium in the steam generator (2), the generated steam enters the main steam manifold (5). The feedwater quality at the pipe side inlet of the steam generator (2) is monitored online in real time by the feedwater monitor (22), and the humidity on the shell side of the steam generator (2) is monitored online in real time by the humidity monitor (23) to ensure that the parameters of the steam generator (2) are normal during operation, the reactor (1) is upgraded to full power operation, and the steam generator (2) is fully loaded. When the purification circuit is put into operation, the following steps are included: 1) When the humidity monitor (23) shows normal and the feedwater monitor (22) shows abnormal, the reactor (1) operates at reduced power, the fourth valve group (12) is closed, and the makeup water pump (21) is started. The makeup water in the makeup water tank (20) is transported to the pipe side of the steam generator (2) through the makeup water pump (21) to ensure the stable feedwater flow of the steam generator (2); 2) When the sixth valve group (15) and the seventh valve group (18) are opened, the purified water delivery pump (17) is started. The water output from the water supply manifold (10) is purified by the water treatment device (16) and then delivered to the water supply manifold (10) by the purified water delivery pump (17) to form a purification loop. 3) After the water supply monitor (22) shows normal operation, close the sixth valve group (15), stop the purified water delivery pump (17), open the fourth valve group (12) and the eighth valve group (19), and when the water supply flow of the steam generator (2) is stable, stop the water supply pump (21) and restore the unit to normal operating conditions. Increase the power of the reactor (1) to the initial operating state, replenish the water tank (20) to the normal liquid level, and then close the eighth valve group (19). Under overpressure protection operating conditions, the following steps are included: When the pressure of the main steam manifold (5) exceeds the design pressure, the third valve group (9) is opened to release the main steam to the exhaust chimney (8). When the pressure of the main steam manifold (5) drops back to the normal operating pressure, the third valve group (9) is closed and the unit returns to normal operating conditions. Under accident emission operating conditions, the following steps are included: When the humidity monitor (23) shows an abnormality, the reactor (1) reduces its power to shutdown, the main helium blower (3) stops operating, the fourth valve group (12) closes, the second valve group (6) and the fifth valve group (13) open, the steam-water mixture in the steam generator (2) is passively discharged, the radioactive feedwater is discharged to the discharge liquid recovery device (14), and the radioactive steam is discharged to the iodine removal purification device (7), and after filtration, it is discharged to the discharge chimney (8).

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