Passive Containment Cooling with Gravity-Driven Reactor Heat Removal
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Solution Overview
Problem
Nuclear reactors face challenges in managing temperature and pressure excursions within containment environments due to limitations in heat transfer capabilities, requiring efficient cooling systems that do not rely on electrical power or operator intervention.
Innovation Solution
A passive containment cooling system is implemented, featuring a coolant reservoir, vertically extending coolant channels, and check valve assemblies that enable one-way flow of coolant fluid based on pressure thresholds, along with fusible plugs for temperature-controlled flooding, allowing for gravity-driven circulation and heat absorption without active pumping or operator control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active cooling systems with pumps and control systems are used, then cooling effectiveness is improved, but energy consumption and system complexity increase
Solution Approach 1:
The cooling system utilizes natural convection currents and gravity-driven flow to circulate coolant without external power sources. The system self-regulates temperature through passive thermal expansion and density differences, eliminating the need for electric pumps and control systems while maintaining effective cooling.
Solution Approach 2:
The patent replaces active mechanical pumping systems with passive fluid dynamics principles. Natural convection and gravity replace electric pumps, and thermal expansion replaces mechanical pressure regulation systems, thereby eliminating energy consumption while maintaining cooling effectiveness.
2Temperature
If control systems with computer-implemented functionality are used, then temperature and pressure control is improved, but system complexity and operator intervention requirements increase
Solution Approach 1:
The system automatically responds to temperature and pressure changes through inherent physical properties. Thermal expansion and contraction, along with density-driven convection currents, provide self-regulating control without computer systems or operator intervention, simplifying the control architecture while maintaining effective temperature and pressure management.
Solution Approach 2:
The patent utilizes changes in physical parameters such as fluid density, thermal expansion, and pressure differentials to automatically regulate system behavior. These parameter changes provide inherent feedback control mechanisms that eliminate the need for complex electronic control systems while maintaining stable containment conditions.
3Power
If heat transfer capabilities are increased to manage heat rejection, then heat removal efficiency is improved, but system complexity and active components increase
Solution Approach 1:
The system employs hydraulic principles using coolant fluid circulation driven by natural convection and gravity. The fluid dynamics and pressure gradients naturally drive heat transfer without mechanical pumps, maintaining high heat removal efficiency while minimizing system complexity through passive fluid-based heat exchange mechanisms.
Solution Approach 2:
The patent utilizes phase transitions of the coolant fluid (such as evaporation and condensation) to enhance heat transfer capabilities. These phase changes provide high latent heat absorption and release, significantly improving heat removal efficiency without requiring complex active cooling systems or additional components.
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 effectively manages containment environment temperatures and pressures by utilizing gravity-driven coolant circulation and passive check valve operations, reducing energy consumption and enhancing safety by eliminating reliance on electrical or operator-driven cooling mechanisms.
Implementation Method 1
the coolant fluid absorbs heat rejected by the nuclear reactor
Implementation Method 2
the coolant fluid rises through the coolant channel from the bottom of the coolant channel to the top of the coolant channel according to a change in coolant fluid buoyancy
Implementation Method 3
the coolant supply conduit is configured to direct a flow of coolant fluid downwards out of the lower region of the coolant reservoir and into the bottom of the coolant channel via the coolant channel inlet according to gravity
Implementation Method 4
the coolant return conduit is configured to direct a flow of the coolant fluid to rise out of the top of the coolant channel via the coolant channel outlet and into the upper region of the coolant reservoir according to increased buoyancy of the coolant fluid at the top of the coolant channel
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A nuclear plant includes a nuclear reactor, a containment structure that at least partially defines a containment environment of the nuclear reactor, and a passive containment cooling system that causes coolant fluid to flow downwards from a coolant reservoir to a bottom of a coolant channel coupled to the containment structure and rise through the coolant channel toward the coolant reservoir due to absorbing heat from the nuclear reactor. A check valve assembly, in fluid communication with the coolant reservoir, selectively enables one-way flow of a containment fluid from the containment environment to the coolant reservoir, based on a pressure at an inlet being equal to or greater than a threshold magnitude. A fusible plug, in fluid communication with the coolant reservoir at a bottom vertical depth below the bottom of the coolant reservoir, enables coolant fluid to flow into the containment structure based on at least partially melting.