Stirling Engine Driven Nuclear Safety System
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Solution Overview
Problem
Existing passive safety systems in nuclear power plants face challenges in recycling waste heat, have limited configuration options, low driving force, and reduced economic efficiency due to reliance on natural circulation and heat exchangers with low heat transfer coefficients.
Innovation Solution
Integration of a Stirling engine into the nuclear safety system to generate power from heat removed during accidents, using this power to drive circulation fans and pumps, and reduce heat exchanger size, enhancing both heat exchange performance and economic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If passive safety systems use natural circulation and heat exchangers to remove heat during accidents, then heat removal function is provided, but heat transfer efficiency is low and heat exchanger size is large
Solution Approach 1:
The patent replaces the natural circulation system with a Stirling engine-driven forced circulation system. The Stirling engine converts thermal energy from the reactor coolant into mechanical work to drive the coolant circulation, substituting passive natural convection with active mechanically-driven flow, thereby improving heat transfer efficiency and reducing heat exchanger size.
Solution Approach 2:
The patent changes the operating parameters of the safety system by introducing a Stirling engine that operates at specific temperature differentials (hot side at 500-900°C, cold side at 20-500°C). This parameter optimization enables efficient thermal-to-mechanical energy conversion, improving overall system efficiency and reducing the required heat exchanger surface area.
2Power
If passive safety systems rely on natural circulation, then system complexity is reduced, but driving force is insufficient
Solution Approach 1:
The Stirling engine is designed to automatically start and operate using the thermal energy already present in the reactor coolant system during accidents. The engine self-regulates based on temperature differentials, converting thermal energy directly into mechanical work to drive coolant circulation, providing sufficient driving force while maintaining relatively simple system architecture.
Solution Approach 2:
The patent merges the heat removal function with power generation by integrating the Stirling engine into the existing safety system. The same thermal field that needs to be managed for safety purposes is simultaneously utilized to generate mechanical work, combining two functions into one integrated system.
3Loss of energy
If waste heat is discharged to external environment, then heat removal is achieved, but economic efficiency is reduced
Solution Approach 1:
The patent converts the harmful waste heat that would normally be discharged to the environment into a beneficial resource. The Stirling engine captures this waste thermal energy and transforms it into useful mechanical work to drive coolant circulation, turning an energy loss into a productive contribution to safety system operation.
Solution Approach 2:
Instead of discarding waste heat to the external environment, the system recovers this thermal energy through the Stirling engine. The engine captures heat from the reactor coolant that would otherwise be wasted and converts it into mechanical energy, recovering value from what would have been a loss.
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 Stirling engine enables the recycling of waste heat for powering safety systems, increasing efficiency and reducing heat exchanger size, thus enhancing safety and economic efficiency while providing a reliable power source without external assistance.
Implementation Method 1
a power generator provided with a heat exchange unit to receive heat removed to an outside of the containment, and provided with a cylinder to generate power by heat received through the heat exchange unit
Implementation Method 2
a heat transfer portion configured to provide a flow path of heat transfer fluid between the reactor coolant system and the power generator or between the containment and the power generator to transfer the heat removed to an outside of the containment to the power generator
Data Source
AI summary
Disclosed is a nuclear power plant which drives a Stirling engine by means of heat generated in nuclear power plant safety systems during an accident, uses the resulting power directly or generates electric power so as to supply the power to the safety systems, and thus can improve economic efficiency as well as the reliability of safety systems, such as a passive safety system, by operating the safety systems without an emergency diesel generator or external electric power.