Integrated Passive Reactor Layout for Infinite-Time Core Cooling
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Solution Overview
Problem
Conventional nuclear power plants with active safety systems rely on external power sources, making them vulnerable to accidents, and large-scale passive pressurized water reactors have complex cooling systems that may not achieve infinite-time cooling, leading to potential radioactive releases and core melting risks.
Innovation Solution
An integrated passive reactor design incorporating a reactor main loop, containment cooling system, residual heat removal system, and core cooling system, which includes a pressure vessel, diversion device, steam generator, and passive safety features like pressure regulators and auxiliary circulation devices, eliminating the need for operator intervention and ensuring infinite-time cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active special system configuration is adopted to alleviate accidents, then the safety of the reactor is improved, but the system relies heavily on external power and power supply, making it vulnerable to accidents when external power is unavailable
Solution Approach 1:
The reactor employs passive safety systems that utilize natural physical phenomena (natural circulation, gravity, phase change) to achieve self-cooling without external power or operator intervention. The system serves itself by using the reactor's own heat to drive circulation and cooling processes, eliminating dependence on external power sources for safety functions.
Solution Approach 2:
The patent replaces active mechanical pumping systems with passive natural circulation systems. Instead of using electric pumps to circulate coolant, the design utilizes natural convection and phase change mechanisms to achieve continuous cooling, thereby eliminating the need for external power-driven mechanical systems during accident conditions.
2Duration of action of stationary object
If a passive core cooling system is designed with high, medium and low pressure safety-injections, then the cooling capability is improved, but the system becomes complex and may not effectively achieve infinite-time cooling
Solution Approach 1:
The cooling system is segmented into multiple functional zones with different pressure levels (high pressure, medium pressure, low pressure injection systems). Each segment handles specific cooling requirements at different stages of the accident progression, enabling systematic and extended cooling over infinite time without requiring a single complex system.
Solution Approach 2:
The system utilizes parameter changes in coolant pressure and temperature to transition between different cooling modes. By dynamically adjusting pressure levels and utilizing phase change at different pressure stages, the system achieves extended cooling capability while maintaining manageable complexity through standardized pressure zones.
3Reliability
If an inner displacement water tank is arranged in the containment, then the containment cooling is improved, but the containment size increases and burden on containment environment conditions increases
Solution Approach 1:
The water tank is merged with the containment structure, utilizing the containment's existing volume for water storage. The tank is positioned to utilize gravity-driven circulation within the containment space, combining the cooling function with the existing containment architecture rather than adding separate independent systems.
Solution Approach 2:
The water tank serves as an intermediary element that mediates between the reactor core and the containment environment. It provides a controlled water reservoir that can be drawn upon for cooling without requiring direct large-volume water storage within the containment, thereby reducing the effective containment volume requirement.
4Speed
If the loop resistance is reduced through reactor-type process design, then the natural circulation capability is improved, but the construction materials of loop pipelines are reduced
Solution Approach 1:
The system optimizes flow resistance parameters by changing the geometry and configuration of loop components. By adjusting pipe diameters, bend radii, and component arrangements to minimize resistance, the system enhances natural circulation capability. This parameter optimization allows for reduced pipe dimensions and fewer materials while maintaining or improving circulation performance.
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 integrated passive reactor enhances safety and economy by simplifying safety systems, reducing loop resistance, and achieving continuous cooling without external power, thereby minimizing core melting risks and radioactive releases.
Implementation Method 1
a steam generator arranged in the pressure vessel... configured in a coil structure wound on the outside of the diversion device
Implementation Method 2
the containment cooling system is configured for exchanging heat inside and outside the containment so as to reduce the temperature and pressure in the containment
Implementation Method 3
the auxiliary circulation device is arranged between the diversion device and the core and is configured for making a fluid in the pressure vessel flow between the core and the pressure vessel so as to form a circulating flow channel
Data Source
AI summary
Integrated passive reactor including a reactor primary circuit, a containment cooling system, a residual heat removal system, and a reactor core cooling system. Loop resistance is reduced by means of a reactor-type process design, a flow guide device is provided at a rising section of fluid to reduce the loop resistance, the rising section is shrunken to increase the arrangement space of a heat exchanger so as to further optimize system resistance, and the designs of an infinite-time passive reactor core residual heat removal system and an infinite-time passive containment cooling system are achieved. By means of the rational configuration of a pressure relief system, high-pressure safety injection is removed, and the passive reactor core cooling system is simplified. By means of the design of an auxiliary circulation device for a loss of coolant accident, the safety of a reactor core in the loss of coolant accident is further enhanced.