A passive water cutoff protection system and method for a high temperature gas cooled reactor steam generator

Abstract

The application discloses a kind of high temperature gas cooled reactor steam generator passive water break protection system and method, the pipe side export of steam generator is divided into two ways, wherein, one way is communicated with the inlet of turbine high-pressure cylinder, the outlet of turbine high-pressure cylinder is communicated with the inlet of turbine low-pressure cylinder, the output shaft of turbine low-pressure cylinder is communicated with the drive shaft of generator;Another way is communicated with the pipe side inlet of heat exchanger in air cooling tower, the pipe side outlet of heat exchanger in air cooling tower is communicated with the pipe side inlet of steam generator;The outlet of turbine low-pressure cylinder is communicated with the inlet of condenser, the outlet of condenser is divided into two ways, wherein, one way is communicated with the pipe side inlet of steam generator;Another way is communicated with the pipe side inlet of steam generator, the outlet of pressure storage water supply tank is communicated with the pipe side inlet of steam generator, the system and method can ensure that unit safe and stable operation under abnormal condition of feedwater system.

Description

Technical Field

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

[0002] The high-temperature gas-cooled reactor's steam generator is a vertical, direct-flow spiral tube type. If the feedwater system malfunctions during unit operation and fails to provide feedwater flow to the steam generator, heat from the reactor core cannot be removed, potentially leading to core failure in extreme cases. Therefore, the current design initiates an emergency shutdown upon feedwater system malfunction, halting both the reactor and steam generator. While this shutdown design ensures core safety, it has at least the following drawbacks: Emergency shutdown is an abnormal operating condition; frequent emergency shutdowns due to feedwater system instability and abnormal malfunctions will impact the lifespan of the steam generator and core. Furthermore, when feedwater system malfunctions are caused by a plant-wide power outage or loss of external AC power, the steam generator and core emergency cooling system cannot operate normally. After an emergency shutdown, heat in the core and steam generator relies on natural cooling, which is time-consuming and ineffective, hindering safe and stable unit operation. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a passive water shortage protection system and method for a high-temperature gas-cooled reactor steam generator. This system and method can ensure the safe and stable operation of the unit under abnormal conditions of the feedwater system.

[0004] To achieve the above objectives, the present invention discloses a passive water shortage protection system for a high-temperature gas-cooled reactor steam generator, comprising a steam generator, a first electric valve, a high-pressure cylinder of a steam turbine, a low-pressure cylinder of a steam turbine, a generator, a first pneumatic valve, an air-cooled tower, a condenser, a second pneumatic valve, a second electric valve, and a pressure accumulator water tank.

[0005] The steam generator's pipe-side outlet is divided into two paths. One path connects to the inlet of the high-pressure cylinder of the steam turbine via a first electric valve, and the outlet of the high-pressure cylinder connects to the inlet of the low-pressure cylinder. The output shaft of the low-pressure cylinder connects to the drive shaft of the generator. The other path connects to the pipe-side inlet of the heat exchanger in the air-cooled tower via a first pneumatic valve, and the outlet of the heat exchanger connects to the pipe-side inlet of the steam generator. The outlet of the low-pressure cylinder of the steam turbine connects to the inlet of the condenser. The condenser's outlet is divided into two paths. One path connects to the pipe-side inlet of the steam generator via a second pneumatic valve, and the other path connects to the pipe-side inlet of the steam generator via a second electric valve. The outlet of the pressure accumulator tank connects to the pipe-side inlet of the steam generator.

[0006] The tube-side outlet of the heat exchanger in the air-cooled tower is connected to the tube-side inlet of the steam generator via the first check valve.

[0007] The outlet of the second pneumatic valve is connected to the pipe-side inlet of the steam generator via the second check valve.

[0008] The second electric valve is connected to the pipe-side inlet of the steam generator via the feed water pump and the third electric valve in sequence.

[0009] The outlet of the accumulator water tank is connected to the pipe-side inlet of the steam generator via the third pneumatic valve.

[0010] The air-cooled tower is equipped with air inlet louvers and air outlet louvers.

[0011] The bottom elevation of the heat exchanger is higher than the top elevation of the steam generator.

[0012] The passive water failure protection method for a high-temperature gas-cooled reactor steam generator according to the present invention includes the following steps:

[0013] During the operation of the steam generator, if the feedwater system malfunctions, the first electric valve, the second electric valve, and the third electric valve will be closed, the generator will be shut down, and the rotors of the high-pressure cylinder and the low-pressure cylinder of the steam turbine will coast down until the speed reaches zero. Then the first pneumatic valve, the second pneumatic valve, and the third pneumatic valve will be opened.

[0014] The steam remaining in the outlet pipe of the first electric valve flows into the high-pressure cylinder and the low-pressure cylinder of the steam turbine in sequence, and then is discharged into the condenser. After condensation in the condenser, it is injected into the pipe-side inlet of the steam generator through the second pneumatic valve to ensure the water supply to the steam generator.

[0015] Steam in the steam generator is discharged into the heat exchanger through the first pneumatic valve. In the heat exchanger, it is absorbed by the cold air in the air-cooled tower and becomes condensate. The condensate is injected into the pipe-side inlet of the steam generator and continues to absorb heat from the shell side of the primary loop of the steam generator and becomes steam again. It continues to be discharged into the heat exchanger to release heat. The entire cycle is carried out by temperature difference and gravity difference, forming a passive circulating water supply loop.

[0016] When the power source driving the passive circulating water supply circuit weakens, the feedwater in the pressurized water tank is injected into the pipe-side inlet of the steam generator to supplement the water supply of the steam generator.

[0017] The air-cooled tower is equipped with air inlet louvers and air outlet louvers.

[0018] The water flow rate of the steam generator can be adjusted by regulating the opening of the air inlet louvers and the air outlet louvers.

[0019] The present invention has the following beneficial effects:

[0020] In practical operation, the passive water shortage protection system and method for high-temperature gas-cooled reactor steam generators described in this invention effectively prevents steam generator water shortage accidents by rapidly supplying condensate from the condenser to the steam generator when an abnormality occurs in the steam generator feedwater system. Simultaneously, the air-cooled tower is activated to form a passive circulating water supply loop for the steam generator, further ensuring stable feedwater supply. Furthermore, the feedwater volume of the steam generator is replenished promptly through a pressurized water tank. By employing multiple loops, the system ensures that the steam generator does not experience water shortage accidents, greatly improving the reliability of the steam generator feedwater supply and thus reducing the probability of reactor core damage.

[0021] Furthermore, in this invention, various operating circuits of the steam generator are isolated from each other and the water supply process by setting check valves, which can automatically activate at each stage of the steam generator's water shortage protection, resulting in high system reliability.

[0022] Furthermore, in extreme accident scenarios such as a complete power outage or loss of external AC power, and the standby diesel generator set is about to shut down, the passive water shortage protection system of this invention uses a pneumatic valve to achieve passive water supply to the steam generator through temperature difference and gravity difference, ensuring the safety of the unit. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Among them, 1 is the steam generator, 2 is the air-cooled tower, 3 is the high-pressure cylinder of the steam turbine, 4 is the low-pressure cylinder of the steam turbine, 5 is the generator, 6 is the condenser, 7 is the feed water pump, 8 is the accumulator water tank, 9 is the first pneumatic valve, 10 is the first electric valve, 11 is the first check valve, 12 is the second electric valve, 13 is the second pneumatic valve, 14 is the second check valve, 15 is the third electric valve, 16 is the third pneumatic valve, 2-1 is the heat exchanger, 2-2 is the air inlet louver, and 2-3 is the air outlet louver. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] refer to Figure 1 The passive water shortage protection system for the high-temperature gas-cooled reactor steam generator described in this invention includes a steam generator 1, an air-cooled tower 2, a high-pressure cylinder of a steam turbine 3, a low-pressure cylinder of a steam turbine 4, a generator 5, a condenser 6, a feedwater pump 7, a pressure accumulator tank 8, a first pneumatic valve 9, a first electric valve 10, a first check valve 11, a second electric valve 12, a second pneumatic valve 13, a second check valve 14, a third electric valve 15, and a third pneumatic valve 16.

[0028] The steam generator 1 has two pipe-side outlets. One outlet connects to the inlet of the high-pressure cylinder 3 of the steam turbine via the first electric valve 10. The outlet of the high-pressure cylinder 3 connects to the inlet of the low-pressure cylinder 4 of the steam turbine, and the output shaft of the low-pressure cylinder 4 connects to the drive shaft of the generator 5. The other outlet connects to the pipe-side inlet of the heat exchanger 2-1 in the air-cooled tower 2 via the first pneumatic valve 9. The pipe-side outlet of the heat exchanger 2-1 in the air-cooled tower 2 connects to the inlet of the first check valve 11, and the outlet of the first check valve 11 connects to the pipe-side inlet of the steam generator 1. The outlet of the low-pressure cylinder 4 of the steam turbine connects to the inlet of the condenser 6, and the outlet of the condenser 6 is divided into... There are two paths. One path is connected to the inlet of the second pneumatic valve 13, the outlet of the second pneumatic valve 13 is connected to the inlet of the second check valve 14, and the outlet of the second check valve 14 is connected to the pipe-side inlet of the steam generator 1. The other path is connected to the inlet of the second electric valve 12, the outlet of the second electric valve 12 is connected to the inlet of the feed water pump 7, the outlet of the feed water pump 7 is connected to the inlet of the third electric valve 15, the outlet of the third electric valve 15 is connected to the pipe-side inlet of the steam generator 1, the outlet of the third pneumatic valve 16 is connected to the pipe-side inlet of the steam generator 1, and the inlet of the third pneumatic valve 16 is connected to the outlet of the pressure accumulator water tank 8.

[0029] The air-cooled tower 2 is equipped with a heat exchanger 2-1, and the air-cooled tower 2 is equipped with an air inlet louver 2-2 and an air outlet louver 2-3. The air-cooled tower 2 is placed at a high position, and the bottom elevation of the heat exchanger 2-1 is higher than the top elevation of the steam generator 1.

[0030] The pressure accumulator tank 8 contains water, and its pressure is maintained by high-pressure nitrogen.

[0031] refer to Figure 1Based on the typical operating conditions of the high-temperature gas-cooled reactor steam generator, this invention discloses a passive water failure protection method for a high-temperature gas-cooled reactor steam generator, comprising the following steps:

[0032] During the operation of steam generator 1, if the feedwater system malfunctions, such as a plant-wide power outage or loss of external AC power, the standby diesel generator set is about to stop, or the feedwater pump 7 fails to work properly, the first electric valve 10, the second electric valve 12, and the third electric valve 15 are closed, the generator 5 is shut down, the rotor of the high-pressure cylinder 3 and the rotor of the low-pressure cylinder 4 of the steam turbine coast down until the speed reaches zero, and the first pneumatic valve 9, the second pneumatic valve 13, and the third pneumatic valve 16 are opened.

[0033] Steam remaining in the outlet pipe of the first electric valve 10 flows sequentially into the high-pressure cylinder 3 and the low-pressure cylinder 4 of the turbine, and then into the condenser 6. After condensation in the condenser 6, it is injected into the pipe-side inlet of the steam generator 1 through the second pneumatic valve 13 and the second check valve 14. This circuit serves as a rapid water supply circuit after the steam generator 1 is shut off.

[0034] Steam from steam generator 1 is discharged into heat exchanger 2-1 via first pneumatic valve 9. In heat exchanger 2-1, steam is absorbed by the cold air in air-cooled tower 2 and becomes condensate. The condensate is injected into the pipe-side inlet of steam generator 1 via first check valve 11 and continues to absorb heat from the shell side of the primary loop of steam generator 1 and becomes steam again. It is then discharged into heat exchanger 2-1 to release heat. The entire cycle is carried out by temperature difference and gravity difference and does not require a power source, forming a passive circulating water supply loop. During this process, the amount of steam condensation is controlled by adjusting the opening of air inlet louvers 2-2 and air outlet louvers 2-3, thereby regulating the water supply flow of steam generator 1.

[0035] As the heat on the shell side of the primary circuit of the steam generator 1 is continuously released, when the power source driving the passive circulating water supply circuit weakens, the feed water in the pressurized water tank 8 is injected into the pipe-side inlet of the steam generator 1. This circuit serves as a supplementary water supply circuit after the steam generator 1 is shut off. During this period, the water supply flow of the steam generator 1 is adjusted by the pressure of the high-pressure nitrogen in the pressurized water tank 8.

[0036] 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 passive water shortage protection system for a high-temperature gas-cooled reactor steam generator, characterized in that, It includes a steam generator (1), a first electric valve (10), a high-pressure cylinder of a steam turbine (3), a low-pressure cylinder of a steam turbine (4), a generator (5), a first pneumatic valve (9), an air-cooled tower (2), a condenser (6), a second pneumatic valve (13), a second electric valve (12), and a pressure accumulator water tank (8); The steam generator (1) has two pipe-side outlets. One outlet is connected to the inlet of the high-pressure cylinder (3) of the steam turbine via the first electric valve (10), and the outlet of the high-pressure cylinder (3) is connected to the inlet of the low-pressure cylinder (4) of the steam turbine. The output shaft of the low-pressure cylinder (4) is connected to the drive shaft of the generator (5). The other outlet is connected to the pipe-side inlet of the heat exchanger (2-1) in the air-cooled tower (2) via the first pneumatic valve (9). The outlet of the turbine low-pressure cylinder (4) is connected to the inlet of the steam generator (1); the outlet of the turbine low-pressure cylinder (4) is connected to the inlet of the condenser (6); the outlet of the condenser (6) is divided into two paths, one of which is connected to the inlet of the steam generator (1) via the second pneumatic valve (13); the other path is connected to the inlet of the steam generator (1) via the second electric valve (12); and the outlet of the pressure accumulator (8) is connected to the inlet of the steam generator (1).

2. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The tube-side outlet of the heat exchanger (2-1) in the air-cooled tower (2) is connected to the tube-side inlet of the steam generator (1) via the first check valve (11).

3. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The outlet of the second pneumatic valve (13) is connected to the pipe-side inlet of the steam generator (1) via the second check valve (14).

4. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The second electric valve (12) is connected to the pipe-side inlet of the steam generator (1) via the water supply pump (7) and the third electric valve (15) in sequence.

5. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 4, characterized in that, The outlet of the accumulator water tank (8) is connected to the pipe-side inlet of the steam generator (1) via the third pneumatic valve (16).

6. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The air-cooled tower (2) is equipped with an air inlet louver (2-2) and an air outlet louver (2-3).

7. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 1, characterized in that, The bottom elevation of the heat exchanger (2-1) is higher than the top elevation of the steam generator (1).

8. A passive water shortage protection method for a high-temperature gas-cooled reactor steam generator, characterized in that, The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 5 includes the following steps: During the operation of the steam generator (1), if the feedwater system is abnormal, the first electric valve (10), the second electric valve (12) and the third electric valve (15) are closed, the generator (5) is stopped, the rotor of the high-pressure cylinder (3) of the steam turbine and the rotor of the low-pressure cylinder (4) of the steam turbine coast down until the speed reaches zero, and then the first pneumatic valve (9), the second pneumatic valve (13) and the third pneumatic valve (16) are opened. The steam remaining in the outlet pipe of the first electric valve (10) flows into the high-pressure cylinder (3) and the low-pressure cylinder (4) of the turbine in sequence, and then is discharged into the condenser (6). After being condensed in the condenser (6), it is injected into the pipe-side inlet of the steam generator (1) through the second pneumatic valve (13) to ensure the water supply of the steam generator (1). Steam in the steam generator (1) is discharged into the heat exchanger (2-1) through the first pneumatic valve (9). In the heat exchanger (2-1), the steam absorbs heat from the cold air in the air-cooled tower (2) and becomes condensate. The condensate is injected into the pipe-side inlet of the steam generator (1) and continues to absorb heat from the shell side of the primary loop of the steam generator (1) and becomes steam. It continues to be discharged into the heat exchanger (2-1) to release heat. The entire cycle process is carried out by temperature difference and gravity difference, forming a passive circulating water supply loop. When the power source driving the passive circulating water supply circuit weakens, the water in the pressurized water tank (8) is injected into the pipe-side inlet of the steam generator (1) to supplement the water supply of the steam generator (1).

9. The passive water shortage protection system for a high-temperature gas-cooled reactor steam generator according to claim 8, characterized in that, The air-cooled tower (2) is equipped with an air inlet louver (2-2) and an air outlet louver (2-3).

10. The passive water shortage protection method for a high-temperature gas-cooled reactor steam generator according to claim 9, characterized in that, The water flow rate of the steam generator (1) is adjusted by adjusting the opening of the air inlet louver (2-2) and the air outlet louver (2-3).

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