Nuclear power generation system and control method with supercritical carbon dioxide as working fluid
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Solution Overview
Problem
Traditional nuclear power generation systems face inefficiencies in thermoelectric conversion, system complexity, and safety issues due to phase changes in water-based coolant systems, leading to potential reactor damage and increased accident risk.
Innovation Solution
A nuclear power generation system using supercritical carbon dioxide as a working fluid, incorporating a compact design with an intermediate heat exchanger, active and passive waste heat discharging systems, and a working fluid filling and recycling system to enhance safety and efficiency, along with a control method for load regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water-based coolant is used in traditional nuclear power generation systems, then heat transfer capability is improved, but phase changes occur during cooling process which can impact reactor pressure vessel lifespan and safety
Solution Approach 1:
The patent changes the working fluid from water to supercritical carbon dioxide, fundamentally altering the thermal and physical parameters of the system. This parameter change eliminates phase transitions while maintaining effective heat transfer, thereby protecting the reactor pressure vessel from thermal stress and extending its lifespan.
Solution Approach 2:
The patent employs supercritical carbon dioxide as a replaceable working fluid that does not undergo phase changes, effectively substituting the traditional water-based coolant system. This substitution removes the harmful phase change effect on the reactor vessel while preserving heat transfer functionality.
2Use of energy by moving object
If traditional steam power generation systems are used, then thermoelectric conversion is achieved, but system complexity increases with more auxiliary systems and larger volume and weight
Solution Approach 1:
The patent utilizes supercritical carbon dioxide with distinct thermodynamic properties compared to water/steam systems. The supercritical state allows for more compact heat exchangers and simplified cycle design, reducing auxiliary systems while maintaining or improving thermoelectric conversion efficiency.
Solution Approach 2:
The patent employs a closed-loop gas turbine system using supercritical carbon dioxide as the working fluid, replacing the traditional steam turbine system. This pneumatic system with gas-phase working fluid eliminates the need for complex steam generation, condensation, and feedwater heating auxiliary systems, thereby simplifying the overall plant configuration.
3Productivity
If supercritical carbon dioxide is used as working fluid, then thermoelectric conversion efficiency is improved and system compactness is achieved, but control complexity increases due to strong non-linear characteristics near critical point
Solution Approach 1:
The patent implements a closed-loop control system with multiple feedback mechanisms to manage the non-linear behavior of supercritical carbon dioxide near its critical point. Sensors monitor temperature, pressure, and flow rate, and the control system continuously adjusts operating parameters to maintain stable and efficient operation despite the fluid's sensitive physical property changes.
4Temperature
If water-based coolant systems are used with phase changes, then heat removal is achieved, but reactor vessel integrity is compromised and safety during shutdowns is reduced
Solution Approach 1:
The patent fundamentally changes the working fluid parameter from water to supercritical carbon dioxide, eliminating phase transitions. This parameter change allows for effective waste heat removal through sensible heating and cooling only, preventing thermal shock and phase-change-induced stress on the reactor vessel, thereby maintaining vessel integrity during both normal operation and shutdown conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves high thermoelectric conversion efficiency, compactness, and inherent safety, enabling efficient load-following capabilities and reducing waste emissions while ensuring safe reactor operation during normal and accident conditions.
Implementation Method 1
The main power generation system is configured to convert thermal energy into electrical energy
Implementation Method 2
An intermediate heat exchanger is arranged within the reactor, further enhancing compactness
Implementation Method 3
near the critical point, the physical properties change drastically, exhibiting strong non-linear characteristics
Implementation Method 4
The novel supercritical carbon dioxide power generation system
Implementation Method 5
An active waste heat discharging system and a passive waste heat discharging system are also provided, which enable the extraction of core heat under reactor accident conditions
Data Source
AI summary
The nuclear power generation system with supercritical carbon dioxide as working fluid includes a main power generation system, a waste heat discharging system, a working fluid filling control system, and a working fluid filling and recycling system, all of which use supercritical carbon dioxide as the working fluid. The main power generation system is configured to convert thermal energy into electrical energy, and includes a reactor and power generation system equipment.