Decoupling heat storage low temperature divertor preheating subcritical steam power generation system for fusion reactor

Abstract

The application discloses a fusion reactor decoupling heat storage low-temperature divertor preheating subcritical steam power generation system and belongs to the technical field of fusion reactor power generation. In order to solve the problem of stable and efficient power generation of a fusion reactor pulse heat source, for the fusion reactor of a high-temperature lithium lead cladding, a high-temperature SCO2 cladding and a low-temperature water-cooled divertor, the application proposes that the high-temperature lithium lead cladding and the high-temperature SCO2 cladding adopt a decoupling heat storage mode respectively, a subcritical steam Rankine cycle power generation is realized through a steam generator, and a low-temperature water-cooled divertor heat source is fully utilized to preheat feed water. The application can improve the power generation efficiency of the fusion reactor.

Description

Technical Field

[0001] This invention belongs to the field of fusion reactor power generation technology, specifically relating to a fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system. Background Technology

[0002] Fusion energy boasts significant advantages such as abundant fuel reserves, inherent safety, and minimal environmental impact, and is widely recognized as one of the ultimate solutions to humanity's energy problems. Currently, fusion reactor research is progressing from physical experimental reactors to engineering demonstration reactors, and the design and optimization of fusion reactor power generation systems have become critical technological bottlenecks that urgently need to be overcome.

[0003] Unlike conventional nuclear fission reactors or thermal power units, which have a continuously stable heat source, fusion reactors are limited by their plasma operating modes, resulting in a significantly pulsed thermal power output. A typical fusion reactor operating cycle includes several hours of high-power operation followed by tens of minutes of intermittent operation. This drastically fluctuating heat source characteristic poses a severe challenge to the continuous and stable operation of downstream power generation systems, the thermal fatigue life of equipment, and the reliable grid connection. Therefore, effectively decoupling the pulsed heat source of fusion reactors from the power generation system, which requires a continuously stable input, is a core challenge in the field of fusion reactor energy conversion.

[0004] Furthermore, fusion reactors contain multiple heat sources with significantly different temperature levels. Taking a lithium-lead supercritical carbon dioxide dual-cooling blanket scheme as an example, the lithium-lead blanket typically operates at a temperature range of 450–600°C, while the supercritical carbon dioxide blanket typically operates at a temperature range of 350–470°C. The divertor, used to remove impurities and helium ash, typically has a cooling water outlet temperature at a lower level of 120–200°C. Simply mixing and utilizing these heat sources of different grades would result in a huge loss of usable energy, severely reducing the overall power generation efficiency of the system. In particular, the heat carried by the divertor, although of lower grade, can reach hundreds of megawatts in thermal power; if it is directly dissipated through a cooling tower, it represents a massive waste of energy.

[0005] In current technologies, research on fusion reactor power generation systems largely focuses on a single blanket concept or simply mixing and storing multiple heat sources. Using a single shared thermal storage system to absorb heat from heat sources of different grades not only fails to resolve the fundamental contradiction of physically isolating the two coolants due to differences in material compatibility, chemical activity, and radioactivity safety requirements, but also mixes high-temperature and low-temperature heat in the storage medium, resulting in significant heat loss. Furthermore, there is a lack of feasible solutions for the effective utilization of heat from cryogenic divertors.

[0006] Therefore, there is an urgent need to propose a fusion reactor power generation system that can safely isolate heat sources with different characteristics, achieve efficient utilization of multi-grade heat in a cascade manner, and fully recover low-temperature waste heat to improve the overall power generation efficiency of the system. Summary of the Invention

[0007] To address the technical challenges of existing fusion reactor power generation systems in simultaneously achieving pulsed heat source stabilization, multi-grade heat source cascade utilization, and efficient low-temperature waste heat recovery, this invention provides a fusion reactor decoupled thermal storage low-temperature divertor preheating subcritical steam power generation system. For fusion reactors with high-temperature lithium-lead cladding, high-temperature SCO2 cladding, and low-temperature water-cooled divertors, this invention proposes a decoupled thermal storage approach for the high-temperature lithium-lead cladding and high-temperature SCO2 cladding, respectively. Subcritical steam Rankine cycle power generation is achieved through a steam generator, and the heat source of the low-temperature water-cooled divertor is fully utilized to preheat the feedwater, thereby improving the fusion reactor power generation efficiency.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system for a fusion reactor includes a lithium-lead cladding, an SCO2 cladding, and a divertor, which together constitute a multi-heat source system for the fusion reactor. The lithium-lead cladding and SCO2 cladding are each equipped with an independent decoupled thermal storage system. The power generation system also includes a subcritical Rankine cycle power generation system. The output of the decoupled thermal storage system is connected to the heating end of the subcritical Rankine cycle power generation system, and the cryogenic regeneration function of the subcritical Rankine cycle power generation system is achieved by the divertor as a heat source. The decoupled thermal storage system is used to smooth the pulsed heat source input to the fusion reactor, and the subcritical Rankine cycle power generation system is used to continuously and stably convert thermal energy into electrical energy. The heat from the lithium-lead cladding is transferred to the thermal storage system of the lithium-lead cladding through a first thermal storage heat exchanger; the heat from the SCO2 cladding is transferred to the thermal storage system of the SCO2 cladding through a second thermal storage heat exchanger.

[0010] Beneficial effects:

[0011] 1. By establishing independent decoupled thermal storage systems for lithium-lead cladding and SCO2 cladding, this invention physically isolates two coolants with different physical properties and chemical compatibility requirements. At the same time, it effectively avoids the pollution of the shared thermal storage medium by the leakage of radioactive lithium-lead materials, and eliminates the risk of a plant-wide shutdown caused by a single loop failure.

[0012] 2. This invention utilizes the heat from a low-temperature divertor to replace the traditional steam extraction and reheating process of a steam turbine, reducing the amount of high-quality steam extracted and allowing more steam to continue expanding and doing work in the low-pressure cylinder, directly increasing the generator output power and achieving efficient reuse of low-grade waste heat.

[0013] 3. This invention uses the mature subcritical Rankine cycle and adds a steam reheater, which effectively reduces the exhaust humidity of the last stage blades of the low-pressure cylinder, significantly improves the operating conditions of the steam turbine, and extends the service life of the equipment.

[0014] 4. By decoupling the thermal storage system for buffer regulation, the present invention enables the system to output stable and controllable electrical power to the grid during both the operation and intermittent periods of the fusion reactor, thus completely decoupling the pulse heat source from stable power generation and enabling the fusion power plant to reliably bear the basic load of the grid. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system of the present invention.

[0016] The attached figures are labeled as follows: 1-Lithium-lead cladding; 2-SCO2 cladding; 3-Diverter; 4-First high-temperature storage tank; 5-First low-temperature storage tank; 6-Second high-temperature storage tank; 7-Second low-temperature storage tank; 8-First heat exchanger; 9-Second heat exchanger; 10-First steam generator; 11-Second steam generator; 12-Reheater; 13-Condenser; 14-Preheater; 15-Deaerator; 16-High-temperature heater; 17-High-pressure cylinder; 18-Medium-pressure cylinder; 19-Low-pressure cylinder; 20-Generator; 21-Lithium-lead electromagnetic pump; 22-CO2 compressor; 23-First low-temperature pump; 24-First high-temperature pump; 25-Second low-temperature pump; 26-Second high-temperature pump; 27-Condensate pump; 28-Circulating water pump; 29-Feed water pump; 30-First isolation valve; 31-Second isolation valve; 32-Third isolation valve; 33-Fourth isolation valve; 34-Fifth isolation valve. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0018] like Figure 1 As shown, the fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system of the present invention includes a fusion reactor multi-heat source system, a decoupled thermal storage system, and a subcritical Rankine cycle power generation system.

[0019] The fusion reactor's multi-heat source system comprises a lithium-lead blanket 1, an SCO2 blanket 2, and a divertor 3, which constitute three independent heat sources with different temperature levels and operating characteristics within the fusion reactor. The lithium-lead blanket 1 uses liquid lithium-lead alloy as both coolant and tritium breeder, operating in the temperature range of 460–600°C; the SCO2 blanket 2 uses supercritical carbon dioxide as coolant, operating in the temperature range of 350–470°C; and the divertor 3 is a water-cooled structure with a cooling water outlet temperature of 120–200°C. Under a typical operating condition, the total thermal power of the lithium-lead blanket 1 and SCO2 blanket 2 is 2500 MW, and the thermal power of the divertor 3 is 700 MW. The fusion reactor operates in a cyclical pattern of 2 hours of operation followed by a 30-minute intermittent operation.

[0020] The lithium-lead cladding 1 and SCO2 cladding 2 are each independently equipped with corresponding decoupled thermal storage systems, namely, a thermal storage loop on the lithium-lead side and a thermal storage loop on the SCO2 side. These two systems are physically isolated and operate independently, each employing a thermal storage medium compatible with its corresponding heat source. Specifically, the thermal storage system of the lithium-lead cladding includes a first high-temperature storage tank 4, a first low-temperature storage tank 5, a second low-temperature pump 25, a second high-temperature pump 26, a third isolation valve 32, a first thermal storage heat exchanger 8, and a first steam generator 10, collectively forming an independent thermal storage and release loop on the lithium-lead side. The thermal storage system of the SCO2 cladding includes a second high-temperature storage tank 6, a second low-temperature storage tank 7, a first low-temperature pump 23, a first high-temperature pump 24, a fourth isolation valve 33, a second thermal storage heat exchanger 9, and a second steam generator 11, collectively forming an independent thermal storage and release loop on the SCO2 side.

[0021] The subcritical Rankine cycle power generation system includes a second steam generator 11, a first steam generator 10, a high-pressure cylinder 17, an intermediate-pressure cylinder 18, a reheater 12, a low-pressure cylinder 19, a generator 20, a condenser 13, a condensate pump 27, a preheater 14, a deaerator 15, a feedwater pump 29, and a high-temperature heater 16. The first steam generator 10 and the second steam generator 11 are arranged in series on the working fluid side to achieve cascaded utilization of thermal energy.

[0022] The low-temperature regeneration function in the subcritical Rankine cycle power generation system is replaced by the heat source of the divertor 3 via the preheater 14; the fusion reactor multi-heat source system provides pulsed thermal energy, the decoupled thermal storage system is used to smooth heat source fluctuations, and the subcritical Rankine cycle power generation system is used to continuously and stably convert thermal energy into electrical energy. The heat from the lithium-lead cladding 1 is transferred to the lithium-lead cladding thermal storage system via the first thermal storage heat exchanger 8; the heat from the SCO2 cladding 2 is transferred to the SCO2 cladding thermal storage system via the second thermal storage heat exchanger 9.

[0023] During fusion reactor operation, the pulsed heat generated by lithium-lead blanket 1 and SCO2 blanket 2 is stored in their respective thermal storage systems through independent thermal storage loops. During fusion reactor downtime, the subcritical Rankine cycle power generation system relies entirely on the heat stored in the decoupled thermal storage systems corresponding to lithium-lead blanket 1 and SCO2 blanket 2 for continuous and stable power generation. The heat source of divertor 3 is always connected to the regenerative system of the subcritical Rankine cycle, using its low-grade heat to heat feedwater through preheater 14, replacing the traditional steam turbine extraction and regeneration method, thereby increasing the turbine output power and improving the overall power generation efficiency of the system.

[0024] Liquid lithium-lead from the outlet of lithium-lead cladding 1 enters the hot side of the first thermal storage heat exchanger 8 via the first isolation valve 30. After heat exchange, it returns to the inlet of lithium-lead cladding 1 via lithium-lead electromagnetic pump 21, forming a cycle. Cooling medium in the first cryogenic storage tank 5 enters the cold side of the first thermal storage heat exchanger 8 via the second cryogenic pump 25 to absorb heat, then enters the first high-temperature storage tank 4 via the third isolation valve 32, and is subsequently sent to the hot side of the first steam generator 10 by the second high-temperature pump 26 to release heat before flowing back to the first cryogenic storage tank 5. Supercritical carbon dioxide from the outlet of SCO2 cladding 2 enters the hot side of the second thermal storage heat exchanger 9 via the second isolation valve 31. After heat exchange, it returns to the inlet of SCO2 cladding 2 via CO2 compressor 22. Cooling medium in the second cryogenic storage tank 7 enters the cold side of the second thermal storage heat exchanger 9 via the first cryogenic pump 23 to absorb heat, then enters the second high-temperature storage tank 6 via the fourth isolation valve 33, and is subsequently sent to the hot side of the second steam generator 11 by the first high-temperature pump 24 to release heat before flowing back to the second cryogenic storage tank 7. Water from the outlet of divertor 3 enters the hot side of preheater 14 via the fifth isolation valve 34. After heat exchange, it returns to the inlet of divertor 3 via circulating water pump 28 to form a cycle. In the power generation circuit, feedwater is preheated by feedwater pump 29 and high-temperature heater 16 before entering the cold side of the second steam generator 11. It then enters the cold side of the first steam generator 10 to be heated into main steam. The main steam enters the high-pressure cylinder 17 and intermediate-pressure cylinder 18 to do work before being discharged into reheater 12 for reheating. The reheated steam enters the low-pressure cylinder 19 to do work, and the exhaust steam is discharged into condenser 13 for condensation. The condensate is sent to preheater 14 via condensate pump 27 to be heated by the residual heat of divertor 3. After deoxygenation, it enters deaerator 15 and is then sent out by feedwater pump 29 to complete the cycle. Generator 20 is coaxially connected to high-pressure cylinder 17, intermediate-pressure cylinder 18, and low-pressure cylinder 19 to output electrical energy.

[0025] The working process of this invention is as follows:

[0026] Liquid lithium-lead flows through the lithium-lead cladding 1 to absorb nuclear heat. Its outlet is connected to the hot-side inlet of the first thermal storage heat exchanger 8 via the first isolation valve 30, transferring heat to the thermal storage medium. After flowing out from the hot-side outlet of the first thermal storage heat exchanger 8, it is pressurized by the lithium-lead electromagnetic pump 21 and driven back to the inlet of the lithium-lead cladding 1, completing the lithium-lead coolant cycle. On the thermal storage medium side, the low-temperature thermal storage medium (in this embodiment, a molten salt compatible with lithium-lead is selected) is stored in the first low-temperature storage tank 5. After being pressurized by the second low-temperature pump 25, it enters the cold side of the first thermal storage heat exchanger 8, absorbs heat and heats up, and then enters the first high-temperature storage tank 4 for storage via the third isolation valve 32. During heat release and power generation, the high-temperature thermal storage medium flows out from the first high-temperature storage tank 4, is pressurized by the second high-temperature pump 26 and enters the hot side of the first steam generator 10 to heat the Rankine cycle working fluid. After releasing heat and cooling down, it returns to the first low-temperature storage tank 5, forming a closed-loop cycle of the thermal storage medium.

[0027] Supercritical carbon dioxide flows through the SCO2 blanket 2 to absorb nuclear heat. Its outlet is connected to the hot-side inlet of the second thermal storage heat exchanger 9 via the second isolation valve 31. After releasing heat, it flows out from the hot-side outlet, is pressurized by the CO2 compressor 22, and sent back to the inlet of the SCO2 blanket 2, completing the SCO2 coolant cycle. On the thermal storage medium side, the low-temperature thermal storage medium (in this embodiment, high-temperature resistant heat transfer oil or molten salt is selected, specifically matched according to the temperature zone) is stored in the second low-temperature storage tank 7. After being pressurized by the first low-temperature pump 23, it enters the cold side of the second thermal storage heat exchanger 9 to absorb heat. After being heated, it enters the second high-temperature storage tank 6 for storage via the fourth isolation valve 33. During heat release, the high-temperature thermal storage medium flows out from the second high-temperature storage tank 6, is pressurized by the first high-temperature pump 24, enters the hot side of the second steam generator 11 to heat the Rankine cycle working fluid, and returns to the second low-temperature storage tank 7 after cooling down.

[0028] The subcritical Rankine cycle power generation system is used to efficiently convert stored thermal energy into electrical energy. Its main steam design parameters are approximately 17 MPa pressure, 540°C temperature, 5 kPa exhaust back pressure, and 278°C feedwater temperature. The specific steam-water flow is as follows: High-temperature, high-pressure main steam first enters the high-pressure cylinder 17 to expand and perform work. The exhaust steam from the high-pressure cylinder is reheated to the rated reheat temperature by the reheater 12, and then sequentially enters the intermediate-pressure cylinder 18 and the low-pressure cylinder 19 to continue expanding and performing work, driving the generator 20 to generate electricity. The exhaust steam from the low-pressure cylinder 19 is condensed into condensate by cooling water supplied by the circulating water pump 28 in the condenser 13. The condensate is pressurized by the condensate pump 27 and then enters the preheater 14. In the preheater 14, the condensate absorbs low-temperature heat from the divertor 3 to complete preliminary preheating, replacing the traditional low-pressure heater extraction and reheating method. The preheated feedwater enters the deaerator 15 for thermal deaeration, then is pressurized by the feedwater pump 29, further heated by the high-temperature heater 16, and then sequentially fed into the cold side of the second steam generator 11 and the first steam generator 10. It is heated, evaporated, and superheated stage by stage, ultimately producing qualified main steam, completing the entire thermodynamic cycle. The high-pressure cylinder 17, intermediate-pressure cylinder 18, and low-pressure cylinder 19 are coaxially connected to the generator 20.

[0029] The system operation is divided into the fusion reactor operation period and the fusion reactor off-peak period.

[0030] During fusion reactor operation, the first isolation valve 30, the second isolation valve 31, the third isolation valve 32, the fourth isolation valve 33, the first cryogenic pump 23, the second cryogenic pump 25, the lithium-lead electromagnetic pump 21, and the CO2 compressor 22 are all activated. Part of the pulsed heat generated by the lithium-lead cladding 1 and the SCO2 cladding 2 is directly used to drive the Rankine cycle for power generation via a steam generator, while the other part is stored as high-temperature sensible heat in the first high-temperature storage tank 4 and the second high-temperature storage tank 6, respectively. The heat from the divertor 3 is continuously supplied to the preheater 14 for preheating the condensate.

[0031] During the fusion reactor's off-peak periods, the aforementioned isolation valves, circulating pumps, and compressors are all shut down, and the lithium-lead cladding 1 and SCO2 cladding 2 no longer transfer heat to the thermal storage system. At this time, the subcritical Rankine cycle power generation system relies entirely on the heat stored in the first high-temperature tank 4 and the second high-temperature tank 6 to maintain rated power generation. By adjusting the flow rate of the high-temperature pumps and the heat release rate of the tanks, the turbine inlet steam parameters can be kept stable, thereby achieving a stable power output to the grid throughout the entire fusion reactor operating cycle. In this embodiment, the system is designed with a net output power of approximately 1200 MW, and the overall efficiency of the fusion reactor energy conversion system can reach over 37%.

[0032] This invention, through the synergistic design of independent decoupled thermal storage and cryogenic divertor preheating and regeneration, successfully constructs a safe, reliable, and efficient fusion reactor power generation system that utilizes multi-grade pulse heat sources in a cascade manner, providing strong technical support for the commercial application of fusion energy.

[0033] In summary, this invention addresses the significant temperature and characteristic differences of heat sources within a fusion reactor by employing a physically isolated independent thermal storage strategy, avoiding energy losses and safety risks associated with mixed thermal storage. The high-temperature lithium-lead cladding 1 (460~600℃) transfers heat to an independent lithium-lead side thermal storage system via a first thermal storage heat exchanger 8. This system uses high-temperature molten salt compatible with lithium-lead as the thermal storage medium, forming a closed loop: cryogenic tank → thermal storage heat exchanger → high-temperature tank → steam generator → cryogenic tank. The high-temperature SCO2 cladding 2 (350~470℃) transfers heat to an independent SCO2 side thermal storage system via a second thermal storage heat exchanger 9. This system uses heat transfer oil or medium-temperature molten salt as the thermal storage medium, forming an independent closed-loop thermal storage cycle. Therefore, this solves the problem of excessive energy losses in series thermal storage caused by large temperature and power differences between the two claddings, while also preventing a single cladding leak from contaminating the shared thermal storage medium and causing a system-wide shutdown. Furthermore, this invention employs a mature subcritical Rankine cycle as the core of energy conversion and achieves efficient utilization of thermal energy through a cascaded arrangement. The first steam generator (corresponding to the lithium-lead side) and the second steam generator (corresponding to the SCO2 side) are arranged in series on the working fluid side to achieve cascaded utilization of thermal energy of different grades. Simultaneously, a reheater is installed to reheat the exhaust steam from the high-pressure cylinder, reducing the humidity of the last-stage blades in the low-pressure cylinder, improving the turbine's operating conditions, and extending equipment life. Finally, this invention uses low-temperature divertor waste heat recovery to replace regenerative extraction steam, fully utilizing low-grade waste heat to improve the overall system efficiency. The heat from the low-temperature water-cooled divertor (120~200℃) is used to preheat the condensate / feedwater of the Rankine cycle, replacing the traditional low-pressure extraction steam regeneration function of the turbine. This reduces the amount of high-quality steam extracted, allowing more steam to expand and do work in the turbine, directly increasing the generator output power.

[0034] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A subcritical steam power generation system for decoupling thermal storage and cryogenic divertor preheating in a fusion reactor, characterized in that, The fusion reactor comprises a lithium-lead cladding, an SCO2 cladding, and a divertor, forming a multi-heat source system. The lithium-lead and SCO2 claddings are each equipped with independent decoupled thermal storage systems. The power generation system also includes a subcritical Rankine cycle power generation system. The output of the decoupled thermal storage system is connected to the heating end of the subcritical Rankine cycle power generation system, and the low-temperature regeneration function of the subcritical Rankine cycle power generation system is achieved by the divertor as a heat source. The decoupled thermal storage system smooths the pulsed heat source input to the fusion reactor, while the subcritical Rankine cycle power generation system continuously and stably converts thermal energy into electrical energy. The heat from the lithium-lead cladding is transferred to its thermal storage system via a first thermal storage heat exchanger; the heat from the SCO2 cladding is transferred to its thermal storage system via a second thermal storage heat exchanger. After the liquid lithium lead absorbs heat through the lithium lead cladding, the outlet of the lithium lead cladding is connected to the inlet of the first isolation valve. The outlet of the first isolation valve is connected to the hot-side inlet of the first heat storage heat exchanger. The heat is transferred to its heat storage system through the first heat storage heat exchanger. The hot-side outlet of the first heat storage heat exchanger is connected to the inlet of the lithium lead electromagnetic pump. After being pressurized by the lithium lead electromagnetic pump, the liquid is pumped back to the inlet of the lithium lead cladding, thus forming a lithium lead cooling cycle.

2. The fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 1, characterized in that, The lithium-lead clad thermal storage system includes a first high-temperature storage tank, a first low-temperature storage tank, a second low-temperature pump, a second high-temperature pump, a third isolation valve, a first thermal storage heat exchanger, and a first steam generator. The cooling medium in the first low-temperature storage tank is pumped by the second low-temperature pump to the cold side of the first thermal storage heat exchanger to absorb heat, and then stored in the first high-temperature storage tank through the third isolation valve. Subsequently, it is pumped by the second high-temperature pump to the hot side of the first steam generator to release heat and then flows back to the first low-temperature storage tank to form a closed loop.

3. The fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 1, characterized in that, The subcritical Rankine cycle power generation system includes a second steam generator, a first steam generator, a high-pressure cylinder, an intermediate-pressure cylinder, a reheater, a low-pressure cylinder, a generator, a condenser, a condensate pump, a preheater, a deaerator, a feedwater pump, and a high-temperature heater. Main steam is drawn from the cold-side outlet of the first steam generator and enters the inlet of the high-pressure cylinder. The outlet of the high-pressure cylinder connects to the inlet of the intermediate-pressure cylinder, the outlet of the intermediate-pressure cylinder connects to the inlet of the reheater, the outlet of the reheater connects to the inlet of the low-pressure cylinder, and the outlet of the low-pressure cylinder connects to the inlet of the condenser. The condensed water enters the inlet of the condensate pump, the outlet of the condensate pump connects to the inlet of the preheater, the outlet of the preheater connects to the inlet of the deaerator, the outlet of the deaerator connects to the inlet of the feedwater pump, the outlet of the feedwater pump connects to the inlet of the high-temperature heater, the outlet of the high-temperature heater connects to the cold-side inlet of the second steam generator, and the cold-side outlet of the second steam generator connects to the cold-side inlet of the first steam generator. The high-pressure cylinder, intermediate-pressure cylinder, low-pressure cylinder, and generator are coaxially driven.

4. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 2, characterized in that, The hot side of the first thermal storage heat exchanger is connected to the circuit containing the lithium-lead cladding to obtain heat, while the cold side of the first steam generator is connected in series in the power generation feedwater circuit to heat the feedwater into main steam.

5. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 1, characterized in that, The SCO2 cladding thermal storage system includes a second high-temperature storage tank, a second low-temperature storage tank, a first low-temperature pump, a first high-temperature pump, a fourth isolation valve, a second thermal storage heat exchanger, and a second steam generator. The low-temperature thermal storage medium is connected from the outlet of the second low-temperature storage tank to the inlet of the first low-temperature pump. The outlet of the first low-temperature pump is connected to the cold-side inlet of the second thermal storage heat exchanger. The cold-side outlet of the second thermal storage heat exchanger is connected to the inlet of the fourth isolation valve. The outlet of the fourth isolation valve is connected to the inlet of the second high-temperature storage tank. The outlet of the second high-temperature storage tank is connected to the inlet of the first high-temperature pump. The outlet of the first high-temperature pump is connected to the hot-side inlet of the second steam generator. The hot-side outlet of the second steam generator is connected to the inlet of the second low-temperature storage tank. The outlet of the second low-temperature storage tank is then connected to the inlet of the first low-temperature pump, forming a closed-loop circulation of the SCO2 side thermal storage medium.

6. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 4, characterized in that, After SCO2 absorbs heat through the SCO2 cladding, the outlet of the SCO2 cladding is connected to the inlet of the second isolation valve, the outlet of the second isolation valve is connected to the hot-side inlet of the second heat storage heat exchanger, and the hot-side outlet of the second heat storage heat exchanger is connected to the inlet of the CO2 compressor. After being pressurized by the CO2 compressor, the CO2 is sent back to the inlet of the SCO2 cladding, thus forming the SCO2 cooling cycle.

7. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 1, characterized in that, The system operation is divided into the fusion reactor operation period and the fusion reactor off-peak period.

8. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 7, characterized in that, During the operation of the fusion reactor, the electromagnetic pump, CO2 compressor, first cryogenic pump, second cryogenic pump, first isolation valve, second isolation valve, third isolation valve, and fourth isolation valve are all open. The heat from the lithium-lead cladding is transferred to the lithium-lead cladding thermal storage system via the first thermal storage heat exchanger, driven by the lithium-lead electromagnetic pump. The heat from the SCO2 cladding is transferred to the SCO2 cladding thermal storage system via the second thermal storage heat exchanger, driven by the CO2 compressor. The cryogenic thermal storage medium in the first cryogenic storage tank is pumped to the first thermal storage heat exchanger by the second cryogenic pump, absorbs the heat from the lithium-lead cladding, heats up, and enters the first high-temperature storage tank. A portion of this medium is stored, and the other portion enters the first steam generator to release heat, cools, and returns to the first cryogenic storage tank. The cryogenic thermal storage medium in the cryogenic storage tank is pumped by the first cryogenic pump to the second thermal storage heat exchanger, where it absorbs heat from the SCO2 cladding and heats up before entering the second high-temperature storage tank. Part of it is stored, while the other part enters the second steam generator to release heat, cools down, and returns to the second cryogenic storage tank. The steam generated by the first steam generator flows sequentially through the high-pressure cylinder and the intermediate-pressure cylinder to expand and do work. The exhaust steam from the intermediate-pressure cylinder is reheated by the reheater and then enters the low-pressure cylinder to continue expanding and doing work. The exhaust steam from the low-pressure cylinder is condensed by the condenser and then enters the preheater, where it absorbs the low-temperature heat from the divertor for preheating. It then enters the deaerator for thermal deoxygenation and subsequently flows sequentially through the second steam generator and the first steam generator to be heated, evaporated, and superheated in stages.

9. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 7, characterized in that, During the fusion reactor's intermittent periods, the lithium-lead electromagnetic pump, CO2 compressor, first cryogenic pump, second cryogenic pump, first isolation valve, second isolation valve, third isolation valve, and fourth isolation valve are all closed. The lithium-lead cladding and SCO2 cladding no longer transfer heat to the thermal storage system. The subcritical Rankine cycle power generation system relies entirely on the heat stored in the first and second high-temperature storage tanks to maintain stable power generation.

10. A fusion reactor decoupled thermal storage cryogenic divertor preheating subcritical steam power generation system according to claim 1, characterized in that, The lithium-lead clad thermal storage system and the SCO2 clad thermal storage system each use a thermal storage medium that matches the corresponding heat source temperature range; the thermal storage medium used in the lithium-lead clad thermal storage system is high-temperature molten salt, and the thermal storage medium used in the SCO2 clad thermal storage system is heat transfer oil or medium-temperature molten salt.

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