Seismically Isolated Nuclear Containment Vessel Support
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Solution Overview
Problem
In nuclear reactors with passive operating systems, seismic and thermal forces can cause significant stress on connections, potentially leading to the inadvertent release of radioactive materials and increased maintenance needs, due to the lack of effective seismic isolation and damping mechanisms.
Innovation Solution
A power module structure with a containment vessel submerged in a liquid pool, supported by a seismically isolated support structure located at or above the midpoint of the containment vessel, utilizing elastic damping devices to attenuate seismic forces and allow constrained rotation, thereby reducing the impact of seismic and thermal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid support structures are used to maintain containment vessel stability, then structural stability is improved, but seismic stress on connections increases
Solution Approach 1:
The patent applies beforehand cushioning by installing seismic isolation devices and damping mechanisms in advance within the support structure. These devices include elastic elements and viscous dampers that are pre-positioned to absorb and dissipate seismic energy before it can transmit significant stress to the containment vessel connections, thereby protecting the structure during earthquake events.
Solution Approach 2:
The patent employs intermediary elements such as seismic isolation bearings and flexible connection components between the rigid containment vessel and the support structure. These intermediaries act as mediators that decouple the transmission path of seismic forces, allowing the containment vessel to remain stable while the intermediary devices absorb and isolate the seismic stresses.
2Reliability
If seismic isolation devices are added to reduce seismic stress, then connection integrity is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated seismic isolation components. The support structure incorporates both load-bearing functions and seismic isolation functions within unified elements, such as combining structural columns with embedded viscous dampers and elastic elements. This integration reduces the number of separate components and simplifies the overall system while maintaining connection integrity.
Solution Approach 2:
The patent utilizes parameter changes in the material properties of the seismic isolation devices, such as varying the viscosity of damping fluids or the elasticity coefficients of spring elements, to optimize performance. By adjusting these parameters during design, the system achieves effective seismic protection with standardized components, avoiding excessive complexity.
3Stress or pressure
If the containment vessel is completely submerged for buoyancy support, then seismic force attenuation is improved, but thermal management complexity increases
Solution Approach 1:
The patent applies universality by designing the liquid pool to serve multiple functions simultaneously: it provides buoyancy support to attenuate seismic forces, acts as a thermal sink for heat removal from the containment vessel, and serves as a radiation shield. This multi-functionality eliminates the need for separate thermal management equipment, reducing overall system complexity while maintaining effective seismic protection.
Solution Approach 2:
The submerged containment vessel utilizes the surrounding liquid pool as a self-service thermal management system. The natural convection and heat transfer properties of the liquid automatically regulate the thermal environment of the containment vessel without requiring active pumping or complex control systems, thereby simplifying thermal management while maintaining seismic attenuation benefits.
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 solution enhances the integrity of connections by reducing seismic and thermal stress, preventing radioactive material release and minimizing maintenance, while maintaining the containment vessel's structural integrity and maneuverability.
Implementation Method 1
A power module is disclosed herein, as comprising a containment vessel completely submerged in a pool of liquid... The power module is supported by the support structure in combination with a buoyancy force of the pool of liquid acting on the containment vessel
Implementation Method 2
A damping device is disposed between the support arm and the mounting structure... The damping device is configured to attenuate seismic forces transferred to the support arm
Data Source
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AI summary
A power module (25) includes a containment vessel (24) completely submerged in a pool of liquid, and a support structure (20) located at or above an approximate midpoint of the containment vessel, or center of gravity of the power module (25). The power module (25) is supported by the support structure (20) in combination with a buoyancy force of the pool of liquid acting on the containment vessel (24).