Nuclear power plant system and operation method for direct power generation and electricity storage of fusion reactor pulse heat source

Abstract

The application discloses a nuclear power plant system and an operation method for direct power generation and electricity storage of a fusion reactor pulse heat source, and belongs to the technical field of nuclear fusion power generation, electricity storage and thermal systems. In order to meet the basic requirement of power grid for stable power output, in view of the inherent problems of the heat storage system of the nuclear fusion reactor pulse heat source, such as huge heat storage capacity, large heat shock and frequent heat shock, a Rankine cycle steam turbine generator capable of following the variable working condition operation of the pulse heat source is adopted to directly generate power, and the pulse electric energy is stabilized and output or stored by using the electricity storage mode; during the intermittent stage of the fusion, steam is generated by an electricity storage power heating boiler to maintain the hot state of the steam turbine. The application cancels the super-large power and complex system heat storage system, eliminates the heat loss of the super-large heat storage tank and the complex pipe system, and eliminates the safety hazards of the high-frequency and large-amplitude heat shock in the heat storage system. On the basis of realizing the power supply following the demand of the power grid, the power generation efficiency of the nuclear power plant is improved, so that the overall economic benefit of the power plant is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of nuclear fusion power generation, energy storage and thermal systems, specifically relating to a nuclear power plant system and operation method that uses a fusion reactor pulse heat source to directly generate and store electricity. Background Technology

[0002] Nuclear fusion energy is characterized by abundant fuel resources, high energy density, and low carbon emissions during operation, making it an important development direction for large-scale, stable, and clean energy in the future. During the operation of a fusion reactor, the heat generated by the fusion reaction is absorbed by components such as the blanket and divertor, and then transported to the steam generator or other intermediate heat exchange equipment through a cooling loop, further driving a steam Rankine cycle, supercritical carbon dioxide cycle, or other power cycles to generate electricity.

[0003] Unlike traditional fission nuclear power plants that rely on a continuous and stable heat source, fusion reactors operate in a periodic pulse mode. During the pulsed operation phase, the fusion thermal power and the steam generator's heating power are at high levels, allowing the turbine generator set to output significant electrical power. During the intermittent pulse phase, the fusion thermal power decreases significantly or even temporarily ceases, causing a drop in the steam flow rate, temperature, and pressure at the steam generator outlet. If the turbine generator set were to operate directly alongside the fusion heat source, its output power would exhibit significant periodic fluctuations, making it difficult to meet the grid's requirements for power supply stability, dispatchability, and power change rate.

[0004] To reduce the impact of fusion pulse heat sources on power output, existing technologies typically consider installing large-capacity thermal storage systems between the fusion heat source and the power cycle. These systems absorb and store some heat during the fusion pulse operation phase and continuously supply heat to the power cycle during the intermittent phases, enabling the turbine to maintain a relatively stable power output. However, to cover the entire pulse intermittent period, these systems usually require large-capacity high-temperature thermal storage tanks, thermal storage medium circulation pumps, large-size heat exchangers, and complex connecting pipelines. This not only increases equipment investment and plant footprint but also results in energy losses due to thermal storage medium insulation, circulation, and multi-stage heat exchange. Furthermore, the high-temperature thermal storage medium may experience corrosion, solidification, leakage, and thermal stratification during long-term operation, further increasing the complexity of system operation and maintenance.

[0005] Eliminating the large-capacity thermal storage system and allowing the fusion heat source to directly drive the steam generator and turbine generator set could shorten the heat transfer path, reduce intermediate heat exchange losses, and simplify the power plant system. However, during the pulse intervals, the steam supply to the turbine decreases sharply, and the temperature of the cylinder, rotor, main steam pipes, and valves drops rapidly. When the next fusion pulse arrives, the high-temperature steam re-enters the turbine, which can easily cause significant temperature changes and thermal stress. Frequent load reduction, steam shutdown, and re-entry processes can also lead to thermal bending of the turbine rotor and fatigue damage to critical components, which is detrimental to the long-term safe operation of the unit. Therefore, even after eliminating the large-capacity thermal storage system, it is still necessary to address the issue of maintaining and rapidly recovering the turbine's thermal state during fusion intervals.

[0006] Electrochemical energy storage systems are characterized by fast response, flexible charge and discharge control, and easy connection to power buses, and can be deployed on the output side of steam turbine generators. During fusion pulse operation, the electrochemical energy storage system absorbs the portion of the steam turbine generator's output power exceeding the grid's planned power. During fusion intermittent periods, the electrochemical energy storage system discharges to the public power bus to compensate for the power gap caused by the reduction in steam turbine generator power, thereby smoothing the power output of the fusion power plant. However, electrochemical energy storage can only address power fluctuations on the grid side and cannot directly prevent the temperature drop and heat loss in the steam turbine caused by steam interruption.

[0007] Therefore, it is necessary to propose a nuclear power plant system that uses a fusion reactor pulse heat source to directly generate and store electricity. Summary of the Invention

[0008] To address the fluctuations in turbine generator output power caused by the periodic changes in heat source power during fusion reactor pulse operation, and the problems associated with large-capacity thermal storage systems such as large equipment size, system complexity, high heat loss, and large footprint, this invention provides a nuclear power plant system and operation method that directly generates and stores electricity from a fusion reactor pulse heat source. The system enables the fusion heat source to directly drive a steam Rankine cycle to generate electricity during the pulse phase, and utilizes an electrochemical energy storage system to absorb or compensate for the difference between the turbine generator output power and the grid demand power. During the fusion intermittent phase, the system uses batteries to directly discharge to the grid and supplies power to an electric boiler to generate auxiliary steam, maintaining the hot operation of the turbine and steam system, thereby improving the operational flexibility, power output stability, and overall economic efficiency of the nuclear power plant. This invention eliminates the need for a large-capacity thermal storage system that bears the entire heat load during pulse intervals. Instead, it smooths out power output through an electrochemical energy storage system and maintains the turbine's hot state using an electrically heated steam generator. This achieves coordinated operation between the fusion heat source, the turbine generator set, the electrochemical energy storage system, and the power grid, thereby reducing system complexity and heat transfer losses, and improving the operational flexibility, power generation efficiency, and economy of the fusion power plant.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A nuclear power plant system for direct power generation and storage using a fusion reactor pulse heat source includes a fusion heat source direct power generation system, an electrochemical energy storage system, and an auxiliary steam maintenance system. The fusion heat source direct power generation system includes a fusion heat source, a steam generator, a steam turbine, and a generator. The cooling medium outlet of the fusion heat source is connected to the hot-side inlet of the steam generator, the hot-side outlet of the steam generator is connected to the cooling medium inlet of the fusion heat source, the steam outlet of the steam generator is connected to the inlet of the steam turbine, and the steam turbine is connected to the generator. The electrochemical energy storage system includes a bidirectional converter and a battery. The battery is connected to the DC side of the bidirectional converter, and the AC side of the bidirectional converter is connected to the power bus between the generator and the power grid. The auxiliary steam maintenance system includes an electric boiler. The power supply terminal of the electric boiler is connected to the AC side of the bidirectional converter, the feedwater inlet of the electric boiler is connected to the steam Rankine cycle feedwater pipeline, and the steam outlet of the electric boiler is connected to the main steam pipeline before the turbine inlet.

[0011] The present invention also provides an operation method for a nuclear power plant system that directly generates and stores electricity using a fusion reactor pulse heat source, including a pulse stable power generation and charging mode, a pulse termination rapid switching mode, an intermittent hot state maintenance mode, and a next pulse start switching mode.

[0012] In the pulsed stable power generation and charging mode, the fusion heat source is in pulsed operation state, driving the steam Rankine cycle to generate electricity and supply power to the grid. The surplus electrical energy output by the generator is stored in the battery through the bidirectional converter, so that the battery is in a net charging state and the electric boiler is kept in a hot standby state.

[0013] In the pulse termination fast switching mode, after the fusion reactor pulse operation terminates, the battery discharges to the grid through the bidirectional converter to compensate for the power gap, and at the same time supplies power to the electric boiler to switch it from hot standby state to auxiliary steam supply state, increase the electric heating power and generate auxiliary steam. When the auxiliary steam reaches the preset connection conditions, the third isolation valve set on the auxiliary steam branch is opened to allow the auxiliary steam to enter the main steam pipeline before the turbine inlet.

[0014] In the intermittent hot state maintenance mode, the fusion heat source is in an intermittent state, the battery continuously discharges to the grid to compensate for the power gap and supplies power to the electric heating boiler, and the electric heating boiler continuously generates auxiliary steam to enter the steam turbine to maintain the hot state operation of the steam turbine.

[0015] In the next pulse start-up switching mode, when the fusion heat source enters the next pulse operation stage and the steam generator has not yet established qualified main steam parameters, the battery continues to compensate for the power gap, and the electric boiler continues to generate auxiliary steam to maintain the operation of the steam turbine. When the main steam reaches the preset connection conditions, the opening of the first isolation valve after the steam outlet of the steam generator is opened or increased, while the opening of the third isolation valve and the heating power of the electric boiler are reduced, so that the main steam gradually replaces the auxiliary steam to supply steam to the steam turbine.

[0016] Beneficial effects:

[0017] 1. This invention enables the fusion pulse heat source to directly drive the steam Rankine cycle for power generation, eliminating the need for a large-capacity thermal storage system to handle the power generation load during the entire fusion intermission period. This reduces the need for large thermal storage tanks, thermal storage medium circulation equipment, and intermediate heat exchange equipment, thereby reducing system complexity, plant footprint, and heat transfer losses.

[0018] 2. This invention utilizes a storage battery to absorb excess electrical energy during the fusion pulse operation phase and directly releases electrical energy to the power grid during the fusion interval phase. This allows the electrochemical energy storage system to compensate for the difference between the output power of the steam turbine generator and the power demand of the power grid, thereby smoothing out the periodic power output fluctuations of the nuclear power plant.

[0019] 3. This invention utilizes a storage battery to supply power to an electric boiler, generating auxiliary steam during the intermittent phase of fusion to maintain the thermal conditions of the turbine and main steam system, reduce the thermal stress caused by frequent turbine shutdowns, cooling, and re-injection of steam, and shorten the unit recovery time when the next fusion pulse arrives.

[0020] 4. This invention achieves grid power balancing and turbine thermal maintenance through direct battery discharge and auxiliary steam supply from an electric boiler, respectively, avoiding the sequential conversion of all stored electrical energy into thermal energy, mechanical energy, and electrical energy. This ensures safe turbine operation while improving system energy utilization efficiency and operational flexibility. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a nuclear power plant system for direct power generation and storage using a fusion reactor pulse heat source, according to the present invention.

[0022] The attached figures are labeled as follows: 1-fusion heat source; 2-steam generator; 3-electric boiler; 4-steam turbine; 5-condenser; 6-feed water pump; 7-regenerator; 8-generator; 9-bidirectional converter; 10-battery; 11-power grid; 12-first isolation valve; 13-second isolation valve; 14-third isolation valve; 15-fourth isolation valve. Detailed Implementation

[0023] 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.

[0024] like Figure 1 As shown, a nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to the present invention includes a fusion heat source direct power generation system, an electrochemical energy storage system, an auxiliary steam maintenance system, and a power grid 11.

[0025] The direct power generation system from the fusion heat source is used to transfer the pulsed heat generated by the fusion heat source 1 to the power cycle and drive the generator 8 to generate electricity. The power cycle can adopt a steam Rankine cycle or a Brayton cycle depending on the heat source temperature and the working fluid. This invention uses the steam Rankine cycle as the main embodiment. The electrochemical energy storage system is used to absorb the surplus electrical energy of the generator 8 during the fusion pulse operation phase and to supply power to the grid 11 and the auxiliary steam maintenance system during the fusion intermittent phase. The auxiliary steam maintenance system is used to generate auxiliary steam during the fusion intermittent phase and to provide the turbine 4 with a steam flow rate that meets the requirements for maintaining the thermal state.

[0026] In an alternative implementation using the Brayton cycle, the steam generator 2 and the steam turbine 4 can be replaced by a circulating working fluid heater and a turbine, respectively, and the electric boiler 3 can be replaced by an electric heating working fluid maintenance device powered by a storage battery, used to maintain the thermal conditions of the turbine and the circulating pipeline during the fusion intermittent phase. Figure 1 The following specific embodiments still take the steam Rankine cycle as an example.

[0027] Furthermore, the fusion heat source direct power generation system includes a fusion heat source 1, a steam generator 2, a steam turbine 4, a condenser 5, a feedwater pump 6, a regenerator 7, a generator 8, a first isolation valve 12, and a second isolation valve 13.

[0028] The cooling medium outlet of the fusion heat source 1 is connected to the hot-side inlet of the steam generator 2, and the hot-side outlet of the steam generator 2 is connected to the cooling medium inlet of the fusion heat source 1, thereby forming a fusion heat source cooling circuit. The heat generated by the fusion heat source 1 is carried away by the cooling medium and transferred to the steam Rankine cycle working medium in the steam generator 2.

[0029] The steam outlet of the steam generator 2 is connected to the inlet of the steam turbine 4 via the first isolation valve 12; the steam turbine 4 is connected to the generator 8 to drive the generator 8 to generate electricity; the exhaust port of the steam turbine 4 is connected to the inlet of the condenser 5, the condensate outlet of the condenser 5 is connected to the inlet of the feedwater pump 6, and the outlet of the feedwater pump 6 is connected to the feedwater inlet of the steam generator 2 via the regenerator 7 and the second isolation valve 13, thereby forming a steam Rankine cycle. The power output terminal of the generator 8 is connected to the power grid 11.

[0030] Furthermore, the electrochemical energy storage system includes a bidirectional converter 9 and a battery 10. The battery 10 is connected to the DC side of the bidirectional converter 9, and the AC side of the bidirectional converter 9 is connected to the power bus between the generator 8 and the power grid 11, enabling the battery 10 to be charged and discharged bidirectionally through the bidirectional converter 9.

[0031] The actual charge / discharge state and power of the storage battery 10 are determined based on the output power of the generator 8, the target power of the power grid 11, the power consumption of the electric boiler 3, other plant power consumption, and the state of charge of the storage battery 10. During the fusion pulse operation phase, the storage battery 10 can receive surplus power from the generator 8 while providing thermal backup power to the electric boiler 3, and is generally in a net charged state based on the cycle average power. During the fusion intermittent phase, the storage battery 10 supplies power to the power grid 11, the electric boiler 3, and necessary plant equipment through the bidirectional converter 9. The AC side of the bidirectional converter 9 is connected in parallel to the power bus between the generator 8 and the power grid 11. The bidirectional converter 9 can switch between rectification and inversion states to control the charging and discharging of the storage battery 10. The power supply terminal of the electric boiler 3 is connected to the AC side of the bidirectional converter 9.

[0032] Furthermore, the auxiliary steam maintenance system includes an electric boiler 3, a third isolation valve 14, and a fourth isolation valve 15. The power supply terminal of the electric boiler 3 is connected to the AC output side of the bidirectional converter 9 to receive electrical energy released by the storage battery 10.

[0033] The feedwater inlet of the electric boiler 3 is connected to the feedwater pipeline of the steam Rankine cycle via an auxiliary feedwater branch, and a fourth isolation valve 15 is installed on the auxiliary feedwater branch. The steam outlet of the electric boiler 3 is connected to the main steam pipeline between the first isolation valve 12 and the steam turbine 4 via an auxiliary steam branch, and a third isolation valve 14 is installed on the auxiliary steam branch. The electric boiler 3 uses the electrical energy released by the storage battery 10 to heat the feedwater, generating auxiliary steam that meets the thermal maintenance requirements of the steam turbine. The auxiliary steam is mainly used to maintain the temperature of the steam turbine 4, the main steam pipeline, and related valves, and is not used to bear the main power generation load during the fusion intermittent phase. The storage battery 10 can be composed of multiple parallel energy storage units. During the fusion reactor pulse operation phase, it provides thermal backup power to the electric boiler 3 and achieves net charging of the entire battery system through time-sharing charging and discharging or group operation of energy storage units.

[0034] In this embodiment, the first isolation valve 12 is used to control the main steam generated by the steam generator 2 to enter the steam turbine 4; the second isolation valve 13 is used to control the feedwater to enter the steam generator 2; the third isolation valve 14 is used to control the auxiliary steam generated by the electric boiler 3 to enter the main steam pipeline; and the fourth isolation valve 15 is used to control the feedwater to enter the electric boiler 3.

[0035] To prevent backflow of main steam and auxiliary steam between different branches, check valves can be installed on the steam outlet branch of the steam generator 2 and the steam outlet branch of the electric boiler 3, respectively. The first isolation valve 12 and the third isolation valve 14 can be control valves with flow regulation function to achieve smooth switching between main steam and auxiliary steam.

[0036] During the fusion pulse operation phase, the first isolation valve 12 and the second isolation valve 13 are open, the third isolation valve 14 is closed, and the fourth isolation valve 15 is opened or closed according to the water level requirements of the electric boiler 3. The steam generated by the steam generator 2 enters the steam turbine 4 to do work, and the generator 8 supplies power to the power grid 11 and other plant equipment. Excess electrical energy is transmitted to the storage battery 10 for storage via the bidirectional converter 9. The thermal backup power of the electric boiler 3 is provided by the storage battery 10, which can be operated in groups through time-sharing charging and discharging or parallel energy storage units, maintaining a net charge throughout the entire pulse phase.

[0037] During the fusion intermittent phase, the steam supply from the steam generator 2 to the turbine 4 is reduced or cut off, and the third isolation valve 14 and the fourth isolation valve 15 are opened, allowing feedwater to enter the electric boiler 3 via the auxiliary feedwater branch. The battery 10 supplies power to the electric boiler 3 through the bidirectional converter 9. The electric boiler 3 heats the feedwater and generates auxiliary steam, which enters the main steam pipeline via the third isolation valve 14 and is then delivered to the turbine 4.

[0038] The auxiliary steam is mainly used to maintain the thermal conditions of the turbine 4, the main steam pipeline and related valves, so that the turbine 4 can be kept in low-load operation, no-load operation or hot standby state, and reduce the temperature change and thermal stress generated when the fusion heat source 1 recovers from the intermittent stage to the pulse stage.

[0039] Based on the above system, the present invention also provides an operation method for a nuclear power plant system that directly generates and stores electricity using a fusion reactor pulse heat source, including a pulse stable power generation and charging mode, a pulse termination rapid switching mode, an intermittent hot state maintenance mode, and a next pulse start-up switching mode. Fusion pulse start-up and fusion pulse termination signals are used to identify the fusion reactor operation stage and enable the corresponding operation mode; the actual charging and discharging state of the battery 10 is determined by the system's real-time power difference and state of charge; the switching between main steam and auxiliary steam is determined by the turbine inlet steam parameters.

[0040] a) Pulse-based stable power generation and charging mode:

[0041] In the pulsed stable power generation and charging mode, the fusion heat source 1 provides heat to the steam generator 2. The steam generated by the steam generator 2 enters the steam turbine 4 to expand and do work, and drives the generator 8 to generate electricity. The generator 8 supplies power to the power grid 11 and other plant equipment. The surplus electrical energy exceeding the above load demand is stored in the battery 10 through the bidirectional converter 9. The battery 10 provides thermal standby power to the electric boiler 3 as needed, and is generally in a net charging state during the pulse phase.

[0042] Specifically, during the pulse operation phase of the fusion reactor, the fusion heat source 1 operates at a set thermal power, and the cooling working fluid transfers the heat generated by the fusion heat source 1 to the steam generator 2. The first isolation valve 12 and the second isolation valve 13 are in the open state, allowing feedwater to enter the steam generator 2 to absorb heat and generate main steam.

[0043] The main steam enters the steam turbine 4 through the first isolation valve 12, expands to do work, and drives the generator 8 to generate electricity. The exhaust steam from the steam turbine 4 enters the condenser 5 for condensation, and the resulting condensate is pressurized by the feedwater pump 6, heated by the regenerator 7, and then returned to the steam generator 2, thus completing the steam Rankine cycle.

[0044] The electrical energy output by generator 8 is prioritized to meet the planned power reception of grid 11 and other plant power consumption. The remaining electrical energy is converted by bidirectional converter 9 and stored in battery 10. The thermal backup power of electric boiler 3 is provided solely by battery 10. Battery 10 can be briefly interrupted from charging and switched to low-power discharge, or different parallel energy storage units can be used for charging and thermal backup power supply respectively, so that the battery system is in a net charging state throughout the entire pulse phase.

[0045] In the pulsed stable power generation and charging mode, the electric boiler 3 remains in hot standby mode. The fourth isolation valve 15 opens or closes according to the water level requirements of the electric boiler 3, and the battery 10 provides partial electrical power to the electric boiler 3 as needed to maintain its internal feedwater temperature, pressure, and steam space status; the third isolation valve 14 remains closed to isolate the auxiliary steam branch from the main steam pipeline.

[0046] b) Pulse termination fast switching mode:

[0047] The fusion reactor ends pulse operation and synchronously outputs a fusion pulse termination status signal, which enables the power compensation mode and the auxiliary steam supply mode. The bidirectional converter 9 controls the battery 10 to reduce its charging power, enter standby mode, or switch to discharge mode based on the power difference between the actual output power of the generator 8 and the target power of the power grid, the power consumption of the electric boiler, and the power consumption of other plants. The electric boiler 3 switches from hot standby mode to auxiliary steam supply mode. When the auxiliary steam reaches the preset connection conditions, it enters the main steam pipeline before the inlet of the turbine 4 through the third isolation valve 14.

[0048] Specifically, when the fusion reactor ends its pulse operation, the thermal power of the fusion heat source 1 rapidly decreases from the pulse operation level to the intermittent stage level or stops generating heat, and the fusion reactor control system synchronously outputs a fusion pulse termination status signal.

[0049] The fusion pulse termination signal is used to enable the power compensation mode. The bidirectional converter 9 controls the battery 10 to reduce its charging power, enter standby mode, or switch to discharge mode based on the power difference between the actual output power of the generator 8, the target power of the grid 11, the power consumption of the electric boiler 3, and other plant power consumption. When the actual output power of the generator 8 can still meet the grid and plant load requirements, the battery 10 can continue to be net charged or enter standby mode; when the actual output power of the generator 8 is lower than the required power, the battery 10 discharges to compensate for the corresponding power shortfall. Simultaneously, the electric boiler 3 switches from hot standby mode to auxiliary steam supply mode, increasing the electric heating power and using the feedwater maintained within a preset temperature and pressure range to generate auxiliary steam.

[0050] The steam generator 2, fusion heat source cooling circuit, and steam pipeline have a certain heat capacity, so they can still generate some main steam for a short period of time after the fusion heat power is terminated. When the pressure, temperature, flow rate, and superheat of the auxiliary steam at the outlet of the electric boiler 3 reach the preset connection conditions, the third isolation valve 14 is opened, allowing the auxiliary steam to enter the main steam pipeline before the inlet of the turbine 4; at the same time, the opening of the first isolation valve 12 is adjusted according to the main steam parameters at the outlet of the steam generator 2, so that the main steam and auxiliary steam supply steam together or the auxiliary steam replaces the main steam. The fusion pulse termination status signal is only used to enable the corresponding operating mode, and the actual switching between the main steam and auxiliary steam is completed according to the steam parameters at the inlet of the turbine 4.

[0051] c) Intermittent hot state maintenance mode:

[0052] The storage battery 10 discharges directly to the power grid 11 via the bidirectional converter 9 and supplies power to the electric boiler 3; the auxiliary steam generated by the electric boiler 3 enters the steam turbine 4 to maintain the preset minimum steam flow and hot operating parameters of the steam turbine 4.

[0053] Specifically, after the fusion reactor enters the intermittent phase, the fusion heat source 1 is in a state of stopped heat production or low-level waste heat, and the steam generator 2 no longer undertakes the main task of maintaining the continuous steam supply of the turbine 4. The first isolation valve 12 and the second isolation valve 13 are in the closed state or maintained at an opening degree adapted to the waste heat discharge, to prevent the auxiliary steam generated by the electric boiler 3 from flowing back into the steam generator 2.

[0054] The storage battery 10 discharges to the power bus via the bidirectional converter 9. The electrical energy released by the storage battery 10 is divided into two parts: the main part is directly supplied to the power grid 11 to compensate for the power shortage caused by the decrease in the output power of the steam turbine generator set; the other part is supplied to the electric boiler 3 to maintain the continuous generation of auxiliary steam.

[0055] The fourth isolation valve 15 is opened, allowing a portion of the feedwater from the outlet side of the feedwater pump 6 to enter the electric boiler 3. The feedwater in the electric boiler 3 generates auxiliary steam that meets the thermal maintenance requirements of the steam turbine. The auxiliary steam enters the main steam pipeline via the third isolation valve 14 and is then transported to the steam turbine 4.

[0056] The auxiliary steam is used to maintain the preset minimum flow rate of the steam turbine 4 and to maintain the thermal conditions of the steam turbine cylinder, rotor, main steam valve, and main steam pipeline. The steam turbine 4 can operate under low load or no-load conditions. The condenser 5, feedwater pump 6, condenser vacuum system, steam turbine shaft sealing system, and necessary cooling systems are kept in operation to form a closed-loop water-steam circulation of the auxiliary steam.

[0057] d) The next pulse initiates the mode switching:

[0058] When the fusion reactor enters the next pulse operation phase, the thermal power of the fusion heat source 1 rapidly changes from the intermittent phase level to the pulse operation level, and the fusion reactor control system synchronously outputs the fusion pulse start status signal. Before the steam generator 2 re-establishes qualified main steam parameters, the battery 10 continues to compensate for the actual power gap, and the electric boiler 3 continues to supply steam. When the main steam reaches the preset connection conditions, the first isolation valve 12 is opened and the opening of the third isolation valve 14 is closed or reduced, and the main steam takes over the auxiliary steam. Only when the generator 8 generates net surplus power and the state of charge of the battery 10 is lower than the set upper limit, does the battery 10 switch to the net charging state.

[0059] Specifically, when the fusion reactor starts running the next pulse, the thermal power of the fusion heat source 1 rapidly changes from the intermittent stage level to the pulse operation level, and the fusion reactor control system synchronously outputs the fusion pulse start status signal.

[0060] Upon receiving the fusion pulse start signal, the opening of the second isolation valve 13 is opened or increased, allowing feedwater to enter the steam generator 2. The heat generated by the fusion heat source 1 is transferred to the steam generator 2 via the cooling working fluid, causing the steam generator 2 to re-establish the main steam pressure, temperature, and flow rate.

[0061] Because the steam generator 2, cooling circuit, and steam pipeline have thermal inertia, the output power of the generator 8 will not immediately recover to the output level of the pulse stability phase after the fusion heat source 1 enters the pulse operation state. When the output power of the generator 8 is still lower than the sum of the grid target power, the power consumption of the electric boiler, and other plant power consumption, the battery 10 continues to discharge through the bidirectional converter 9 to compensate for the actual power shortfall.

[0062] While the main steam at the outlet of the steam generator 2 has not yet reached the permitted connection conditions, the electric boiler 3 continues to generate auxiliary steam and maintain the hot operation of the steam turbine 4. When the pressure, temperature, flow rate, and superheat of the main steam at the outlet of the steam generator 2 reach the preset connection conditions, the opening of the first isolation valve 12 is opened or increased, while the opening of the third isolation valve 14 and the heating power of the electric boiler 3 are decreased, so that the main steam replaces the auxiliary steam.

[0063] Once the main steam can independently meet the operating requirements of the turbine 4, the third isolation valve 14 is closed, and the electric boiler 3 returns to hot standby mode. Only when the actual output power of the generator 8 is greater than the sum of the grid target power, the electric boiler hot standby power, and other plant power, and the state of charge of the battery 10 is lower than the set upper limit, will the bidirectional converter 9 switch from the discharging or standby state to the charging state.

[0064] This invention utilizes a portion of the electrical energy stored in an electrochemical energy storage system to power an electrically heated steam generator. During fusion intermissions, this energy heats the feedwater and generates auxiliary steam. The auxiliary steam maintains the thermal conditions of the turbine, main steam pipeline, and related valves, thereby reducing the temperature shock during the next fusion pulse recovery and shortening the unit's load ramp-up time. During intermissions, the primary compensation power required by the grid is still directly supplied by the electrochemical energy storage system through the public power bus, avoiding multiple energy conversion losses caused by the sequential processes of electrical energy passing through electric heating, steam power generation, and regeneration.

[0065] Example:

[0066] The following is a set of example parameters used to illustrate the operation of this invention. These parameters are only used to explain the power distribution and operating logic of the system and do not constitute a limitation on the actual engineering parameters of fusion reactors, steam turbines, electric boilers, and batteries.

[0067] In this embodiment, the fusion reactor adopts a periodic pulse operation mode, with each operating cycle lasting 130 minutes, including a fusion pulse duration of 2 hours and a fusion interval duration of 10 minutes. The usable thermal power delivered to the hot side of the steam generator 2 via the fusion reactor cooling circuit is 2712 MW.

[0068] For simplicity, it is assumed that the effective heat generated by the fusion heat source 1 is transported to the steam generator 2 via a cooling circuit, and the overall thermoelectric conversion efficiency from the fusion reactor to the generator side is taken as 35%. The output power of the generator 8 during the pulse stabilization phase is approximately: 2712 × 35% = 949.2 MW.

[0069] In this embodiment, the planned output power of the power grid 11 is set to 830MW, the power consumption of other plants is set to 20MW, and the thermal standby power of the electric boiler 3 is set to 5MW, which is provided only by the battery 10. During the fusion pulse operation phase, after the generator 8 meets the power needs of the power grid and other plants, the AC power available for charging the battery is approximately 949.2-830-20=99.2MW.

[0070] The charging and discharging efficiencies of the bidirectional converter 9 are both taken as 96%. During the 2-hour fusion pulse operation phase, the battery 10 receives surplus electrical energy and provides thermal standby power to the electric boiler 3 as needed. Taking into account charging losses and thermal standby power supply losses on the AC side, the net stored electrical energy of the battery 10 is approximately 99.2 × 2 × 0.96 - 5 × 2 ÷ 0.96 = 180.0 MWh.

[0071] The rated power of the electric boiler 3 is 40MW, and the electrothermal conversion efficiency is 98%. During the 10-minute fusion interval, to conservatively determine the energy storage capacity, the waste heat of the steam generator and the small amount of electrical power generated by the auxiliary steam-driven turbine 4 are temporarily ignored; the battery 10 supplies power to the grid 11, the electric boiler 3 and other plant equipment through the bidirectional converter 9, and the total output power on the AC side is approximately 830+40+20=890MW.

[0072] The DC-side electrical energy that battery 10 needs to release during the 10-minute interval is approximately 890 × (10 ÷ 60) ÷ 0.96 = 154.5 MWh.

[0073] Therefore, after accounting for the standby power consumption of the electric boiler, other plant power consumption, and the charging and discharging losses of the bidirectional converter, the net stored energy of 180.0 MWh during the pulse phase can meet the discharge demand of approximately 154.5 MWh during the 10-minute intermittent phase, while retaining an energy margin of approximately 25.5 MWh. The parameters described only represent an exemplary power balance within one design cycle; in actual operation, the planned output power of the power grid or the charging power can be adjusted according to the battery's state of charge.

[0074] In this embodiment, the rated capacity of the battery 10 is 300MWh, and the allowable state of charge (SOC) range is 15% to 85%; the rated power of the bidirectional converter 9 is 900MW. If the SOC of the battery 10 is approximately 20% at the start of the fusion pulse, after a 2-hour pulse phase of net charging, the SOC rises to approximately 80%; after a 10-minute intermittent phase of discharging, the SOC decreases to approximately 28.5%, which is still higher than the set lower limit.

[0075] The battery 10 can be composed of multiple energy storage battery cells connected in parallel to meet the requirements of high-power discharge in a short time. The specific type of the battery 10 can be a power-type lithium-ion battery or other electrochemical energy storage device with fast charging and discharging capabilities.

[0076] In this embodiment, the input electrical power of the electric boiler 3 is 40MW, and its effective thermal power is approximately 39.2MW based on a 98% electrothermal conversion efficiency. Assuming that the heat absorption per unit mass required for feedwater to be converted into auxiliary steam by the electric boiler 3 is approximately 1.96MJ / kg, the electric boiler 3 can generate approximately 20kg / s of auxiliary steam.

[0077] The steam generator 2 operates at a thermal power of 2712MW. If the heat absorption per unit mass of the main circulating working fluid in the steam generator 2 is approximately 2.40MJ / kg, then the main steam flow rate during the pulse steady-state phase is approximately 1130kg / s. Therefore, the auxiliary steam flow rate during the intermittent phase is approximately 1.8% of the rated main steam flow rate.

[0078] The auxiliary steam flow is not used to maintain the rated power output of the steam turbine, but mainly to maintain the temperature of the turbine's flow path, cylinder, rotor, main steam pipes, and valves. In actual engineering, the power output and auxiliary steam flow of the electric boiler 3 can be adjusted based on the turbine's minimum stable flow rate, the cylinder metal temperature change rate, the rotor expansion differential, and the duration of the fusion intermittent.

[0079] In this embodiment, the main steam parameters at the outlet of the steam generator 2 can be a pressure of 14 MPa and a temperature of 540°C; the auxiliary steam parameters at the outlet of the electric boiler 3 can be a pressure of 13.5–14 MPa and a temperature of 500–530°C. Before the auxiliary steam is connected to the main steam pipeline, the relative deviation between the steam pressure at the outlet of the electric boiler 3 and the pressure in the main steam pipeline is ensured to be no more than 5%, and the temperature deviation is ensured to be no more than 20°C, in order to reduce the thermal shock during the switching process between the two types of steam.

[0080] During the 2-hour fusion pulse operation phase, the electric boiler 3 is powered by the battery 10 and kept in hot standby mode. Its internal feedwater, steam space, and superheated components are maintained within a preset temperature and pressure range, and the third isolation valve 14 remains closed. The battery 10 can provide approximately 5MW of hot standby power to the electric boiler 3 at preset time intervals and receive surplus power from the generator 8 during the remaining time periods, thus achieving net charging throughout the pulse phase. After the fusion pulse ends, the fusion reactor control system synchronously outputs a fusion pulse termination status signal. The bidirectional converter 9 adjusts the discharge power of the battery 10 according to the difference between the actual output power of the generator 8 and the grid target power, the electric boiler power, and other plant power. The electric boiler 3 switches from hot standby mode to 40MW auxiliary steam supply mode. When the pressure, temperature, flow rate, and superheat of its outlet auxiliary steam reach the preset connection conditions, the third isolation valve 14 is opened, allowing the auxiliary steam to enter the turbine 4.

[0081] After the 10-minute intermittent phase, the fusion reactor enters the next pulse operation phase, and the available thermal power rapidly recovers to 2712MW. The fusion reactor control system synchronously outputs a fusion pulse start status signal. Before the steam generator 2 re-establishes qualified main steam parameters and the generator 8 restores sufficient output power, the battery 10 continues to compensate for the actual power shortfall of the grid 11, the electric boiler 3, and other plant loads, and the electric boiler 3 continues to provide auxiliary steam. When the pressure, temperature, flow rate, and superheat of the main steam meet the preset connection conditions, the opening of the first isolation valve 12 is opened or increased, and the opening of the third isolation valve 14 is decreased, so that the main steam replaces the auxiliary steam. When the generator 8 generates net surplus power and the state of charge of the battery 10 is lower than the set upper limit, the bidirectional converter 9 controls the battery 10 to stop discharging and switch to a net charging state.

[0082] Through the above operating mode, without setting up a large-capacity thermal storage system to handle the heat load of the entire 10-minute fusion interval, the nuclear power plant can maintain a planned output power of approximately 830MW to the grid according to the example parameters, and use a small flow rate of auxiliary steam of approximately 20kg / s to maintain the turbine's no-load rotation or preset low-load hot state operation. The above parameters are idealized examples and do not constitute limitations on actual equipment capacity, operating pressure, and control strategies. The steam Rankine cycle can also be extended to the supercritical carbon dioxide Brayton cycle.

[0083] In summary, this invention eliminates the need for a large-capacity thermal storage system to handle the entire power generation load during the fusion pulse's off-peak period. Instead, it allows the fusion pulse heat source to directly drive a steam Rankine cycle for power generation, transferring the difference between the turbine generator's output power and the grid's planned power to an electrochemical energy storage system. This achieves a shift from "thermal energy storage smoothing" to "electrical energy storage smoothing," reducing the need for large thermal storage tanks, thermal medium circulation equipment, and intermediate heat exchange links. This invention enables the battery to simultaneously perform two functions: grid power compensation and auxiliary steam power supply. During the fusion pulse operation phase, it absorbs excess electrical energy; during the fusion off-peak period, it primarily discharges directly to the grid via a bidirectional converter, supplying a portion of the electrical energy to an electric boiler to generate a small flow of auxiliary steam. This avoids the need for all stored electrical energy to repeatedly undergo multiple stages of conversion between electrical energy, thermal energy, mechanical energy, and electrical energy. This invention employs a rapid coordinated switching method triggered by the start and end signals of the fusion pulse, enabling the battery to quickly switch between charging and discharging, and allowing the electric boiler, which is kept in thermal standby, to quickly supply steam after the pulse ends. The main steam and auxiliary steam are switched according to pressure, temperature, dryness, and flow conditions to maintain the turbine's thermal state and reduce the thermal shock when the next pulse resumes.

[0084] 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 nuclear power plant system for direct power generation and storage using a fusion reactor pulse heat source, characterized in that, The system includes a fusion heat source direct power generation system, an electrochemical energy storage system, and an auxiliary steam maintenance system. The fusion heat source direct power generation system includes a fusion heat source, a steam generator, a steam turbine, and a generator. The cooling medium outlet of the fusion heat source is connected to the hot-side inlet of the steam generator, the hot-side outlet of the steam generator is connected to the cooling medium inlet of the fusion heat source, the steam outlet of the steam generator is connected to the inlet of the steam turbine, and the steam turbine is connected to the generator. The electrochemical energy storage system includes a bidirectional converter and a battery. The battery is connected to the DC side of the bidirectional converter, and the AC side of the bidirectional converter is connected to the power bus between the generator and the power grid. The auxiliary steam maintenance system includes an electric boiler. The power supply terminal of the electric boiler is connected to the AC side of the bidirectional converter, the feedwater inlet of the electric boiler is connected to the steam Rankine circulation feedwater pipeline, and the steam outlet of the electric boiler is connected to the main steam pipeline before the inlet of the steam turbine.

2. A nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to claim 1, characterized in that, The turbine exhaust port is connected to the condenser inlet, the condensate outlet of the condenser is connected to the feedwater pump inlet, and the feedwater pump outlet is connected to the steam generator feedwater inlet via a regenerator.

3. A nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to claim 2, characterized in that, The steam outlet of the steam generator is connected to the inlet of the steam turbine via a first isolation valve, and the outlet of the feedwater pump is connected to the feedwater inlet of the steam generator via a second isolation valve. The feedwater inlet of the electric boiler is connected to the feedwater pipeline on the outlet side of the feedwater pump via an auxiliary feedwater branch. A fourth isolation valve is installed on the auxiliary feedwater branch. The steam outlet of the electric boiler is connected to the main steam pipeline between the first isolation valve and the steam turbine via an auxiliary steam branch. A third isolation valve is installed on the auxiliary steam branch.

4. A nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to claim 3, characterized in that, The first and third isolation valves are control valves with flow regulation functions, and check valves are respectively installed on the steam outlet branch of the steam generator and the steam outlet branch of the electric boiler.

5. A nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to claim 1, characterized in that, The battery consists of multiple parallel energy storage battery cells, and the bidirectional converter can switch between rectification and inversion states to control the charging and discharging of the battery.

6. A method for operating a nuclear power plant system for direct power generation and storage from a fusion reactor pulse heat source according to any one of claims 1 to 5, characterized in that, This includes pulse stable power generation and charging mode, pulse termination fast switching mode, intermittent hot state maintenance mode, and next pulse start switching mode; In the pulsed stable power generation and charging mode, the fusion heat source is in pulsed operation state, driving the steam Rankine cycle to generate electricity and supply power to the grid. The surplus electrical energy output by the generator is stored in the battery through the bidirectional converter, so that the battery is in a net charging state and the electric boiler is kept in a hot standby state. In the pulse termination fast switching mode, after the fusion reactor pulse operation terminates, the battery discharges to the grid through the bidirectional converter to compensate for the power gap, and at the same time supplies power to the electric boiler to switch it from hot standby state to auxiliary steam supply state, increase the electric heating power and generate auxiliary steam. When the auxiliary steam reaches the preset connection conditions, the third isolation valve set on the auxiliary steam branch is opened to allow the auxiliary steam to enter the main steam pipeline before the turbine inlet. In the intermittent hot state maintenance mode, the fusion heat source is in an intermittent state, the battery continuously discharges to the grid to compensate for the power gap and supplies power to the electric heating boiler, and the electric heating boiler continuously generates auxiliary steam to enter the steam turbine to maintain the hot state operation of the steam turbine. In the next pulse start-up switching mode, when the fusion heat source enters the next pulse operation stage and the steam generator has not yet established qualified main steam parameters, the battery continues to compensate for the power gap, and the electric boiler continues to generate auxiliary steam to maintain the operation of the steam turbine. When the main steam reaches the preset connection conditions, the opening of the first isolation valve after the steam outlet of the steam generator is opened or increased, while the opening of the third isolation valve and the heating power of the electric boiler are reduced, so that the main steam gradually replaces the auxiliary steam to supply steam to the steam turbine.

7. The operating method according to claim 6, characterized in that, In the pulse stable power generation and charging mode, the battery provides thermal backup power to the electric boiler to maintain its internal feedwater temperature and pressure; in the pulse termination rapid switching mode, the opening of the first isolation valve is adjusted according to the main steam parameters at the steam generator outlet, so that the main steam and auxiliary steam supply steam together or the auxiliary steam takes over the main steam.

8. The operating method according to claim 6, characterized in that, In the next pulse start-up switching mode, the smooth switching between main steam and auxiliary steam is achieved by coordinating and adjusting the opening of the first isolation valve and the third isolation valve; when the main steam completely replaces the auxiliary steam, the electric boiler returns to the hot standby state.

9. The operating method according to claim 6, characterized in that, The actual charge / discharge state and power of the battery are determined based on the generator's output power, the grid's target power, the electric boiler's power consumption, and the battery's state of charge. Only when the generator's actual output power is greater than the sum of the grid's target power, the electric boiler's thermal standby power, and the plant's power consumption, and the battery's state of charge is lower than the set upper limit, will the bidirectional converter switch to the charging state, allowing the battery to enter a net charging state.

10. The operating method according to claim 6, characterized in that, In the pulse termination fast switching mode, intermittent hot state maintenance mode and next pulse start switching mode, the battery discharge power prioritizes to meet the compensation needs of the power grid gap, and the remaining discharge power is used to supply the electric boiler; when the battery's state of charge is lower than the set lower limit, the heating power of the electric boiler is reduced or the auxiliary steam supply is stopped.

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