Seismic Isolation Assembly Using Plastic Deformation for Nuclear Reactors
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Solution Overview
Problem
Nuclear reactor systems face challenges in effectively managing dynamic forces, such as those generated by seismic events, which can lead to excessive accelerations and forces within the structure, requiring innovative solutions to dissipate seismic energy and ensure safe operation.
Innovation Solution
The implementation of a nuclear reactor seismic isolation assembly that includes a plastically-deformable member and a stretching member within an enclosure, which plastically deforms to dissipate dynamic forces, utilizing friction and working fluid compression to absorb seismic energy, thereby reducing reaction forces on the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional seismic isolation hardware (e.g., springs) is positioned between substructure and superstructure, then the fundamental period of vibration is increased and dynamic response is minimized, but the device complexity and maintenance requirements increase
Solution Approach 1:
The patent changes the material parameter of the isolator from elastic (springs) to plastically-deformable, fundamentally altering the energy dissipation mechanism. This allows the system to achieve seismic isolation through controlled plastic deformation rather than elastic storage, simplifying the overall assembly while maintaining effectiveness
Solution Approach 2:
The patent converts the typically harmful plastic deformation (permanent damage) into a beneficial energy dissipation mechanism. By designing the isolator to undergo controlled plastic deformation during seismic events, the system transforms what is normally considered structural failure into a useful damping mechanism that protects the reactor structure
2Force
If mechanisms are employed to reduce spectral response amplitudes to manageable levels, then deflections and forces are reduced, but the device complexity and maintenance needs increase
Solution Approach 1:
The patent employs a replaceable plastically-deformable member that is designed to be replaced after seismic events rather than repaired. This approach treats the isolator as a sacrificial component that absorbs seismic energy through controlled damage, eliminating complex maintenance requirements while effectively reducing spectral response forces
Solution Approach 2:
The patent extracts the plastically-deformable member as a separate, standalone component within the isolation assembly, allowing it to be independently replaced without affecting other system components. This modular extraction simplifies maintenance operations while maintaining force reduction capabilities
3Loss of energy
If plastically-deformable members are used to dissipate seismic energy, then seismic energy is absorbed and reaction forces are limited, but the manufacturing precision and quality control requirements increase
Solution Approach 1:
The patent incorporates pre-formed plastic deformation zones within the isolator design, where the geometry and material properties are predetermined to ensure controlled deformation behavior. This preliminary design of the deformation path eliminates the need for complex real-time control during seismic events, reducing manufacturing precision requirements while ensuring reliable energy dissipation
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 solution limits reaction forces to sliding forces, reduces maintenance complexities, and accommodates modular design, ensuring safe operation and cost-effective replacement of components during seismic events, while maintaining coolable geometry and global applicability.
Implementation Method 1
a plastically-deformable member mounted, at least in part, within the volume; and a stretching member moveable within the enclosure to plastically-deform the plastically-deformable member in response to a dynamic force exerted on the enclosure
Implementation Method 2
generating friction between the deformable member and the stretching member based on repeated movement of the stretching member into the deformable member based on the received force; and dissipating another portion of the received force based on the generated friction
Implementation Method 3
compressing a working fluid enclosed in a chamber of the deformable element based on movement of the stretching member into the deformable member based on the received force; and dissipating another portion of the received force based on the compression of the working fluid
Data Source
AI summary
A nuclear reactor seismic isolation assembly includes an enclosure that defines a volume; a plastically-deformable member mounted, at least in part, within the volume; and a stretching member moveable within the enclosure to plastically-deform the plastically-deformable member in response to a dynamic force exerted on the enclosure.