Underground Boiling Water Reactor Containment With External Emergency Cooling
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Solution Overview
Problem
Large-scale nuclear reactors like ESBWRs have high construction costs, require large above-ground containments, and are prone to coolant leaks due to extensive piping and flowpaths, limiting their modularity and flexibility for immediate or peaking power generation.
Innovation Solution
A smaller, underground nuclear reactor design with a simplified containment structure using isolation valves and external coolant sources, minimizing penetrations and eliminating the risk of coolant leaks, while maintaining natural circulation for cooling and incorporating passive safety features like isolation condensers for emergency heat removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large-scale nuclear reactors with extensive piping and flowpaths are used, then power generation capacity is increased, but the risk of coolant leaks increases and modularity decreases
Solution Approach 1:
The reactor system is divided into modular components that can be independently contained and sealed. Each module has its own containment structure with limited penetrations, isolating potential leak sources. The primary coolant system is segmented into separate loops with individual isolation capabilities, preventing system-wide contamination from localized failures.
Solution Approach 2:
Isolation condensers serve as intermediary devices between the primary coolant system and the environment. They provide a controlled interface for heat removal while maintaining containment integrity. The condensers act as buffers that can isolate the primary system from external influences, preventing direct exposure of coolant to potential leak paths.
2Reliability
If large above-ground containments are used, then reactor safety is improved, but construction costs increase and plant footprint increases
Solution Approach 1:
The containment structure utilizes a thin-film flexible membrane that provides effective sealing and containment. This membrane, combined with a rigid support structure, achieves containment integrity with less material than traditional thick concrete containments. The flexible nature of the membrane allows for optimized structural design that reduces material usage while maintaining safety requirements.
Solution Approach 2:
The design employs simplified containment geometries and standardized components that can be manufactured more efficiently. By using regular polyhedral shapes and modular construction elements, the design reduces manufacturing complexity and cost while maintaining adequate safety margins through proven engineering principles.
3Power
If extensive piping and flowpaths are used, then cooling capacity is increased, but device complexity increases and coolant leak risk increases
Solution Approach 1:
The heat removal function is extracted from the complex internal piping system and placed in external isolation condenser units. This separates the primary coolant loop from the heat rejection system, simplifying the internal reactor design while maintaining adequate cooling capacity. The external condensers can be optimally configured for heat transfer without adding complexity to the reactor vessel or primary system.
Solution Approach 2:
The natural circulation cooling system utilizes buoyancy-driven flow to eliminate the need for complex pumping systems and control mechanisms. The density differences created by temperature variations automatically drive coolant circulation, providing self-regulating cooling that reduces device complexity while maintaining adequate heat removal capacity under normal operating conditions.
4Adaptability or versatility
If modular and flexible reactor designs are used, then adaptability for immediate or peaking power generation is improved, but construction simplicity may be compromised
Solution Approach 1:
The reactor is designed as a collection of standardized modular units that can be configured in different arrangements to meet varying power demands. Each module is self-contained with standardized interfaces, allowing for rapid deployment and flexible scaling. The modular design enables plants to be constructed in stages or configured for base load, intermediate load, or peaking service as needed.
Solution Approach 2:
The reactor modules are designed with universal characteristics that allow them to serve multiple functions and be deployed in various configurations. The same basic module design can be used for different power generation scenarios by varying the number and arrangement of modules, eliminating the need for specialized designs for different operational requirements and simplifying manufacturing through standardization.
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
This design reduces the risk of coolant loss accidents, allows for flexible and responsive power generation, decreases plant footprint, and simplifies construction and operation, while ensuring reliable long-term cooling and seismic protection.
Implementation Method 1
Reactor 42 is conventionally capable of producing and approved to produce several thousand megawatts of thermal energy through nuclear fission
Implementation Method 2
natural circulation cooling
Implementation Method 3
Suppression pool 59 may include an emergency steam vent used to divert steam from a main steam line into suppression pool 59 for condensation and heat sinking
Implementation Method 4
a gravity-driven cooling system (GDCS) pool 37 can further provide coolant to reactor 42
Data Source
AI summary
Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.