Modular Reactor Support Assembly for Seismic Isolation and Cooling
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Solution Overview
Problem
Current nuclear reactor designs face challenges in seismic isolation and cooling efficiency, with seismically isolated structures being costly, complex, and time-consuming to construct, and existing cooling systems being hindered by thick concrete floors that reduce cooling effectiveness and increase structural loads on seismic isolators.
Innovation Solution
The Modular Isolated Reactor Support System (MIRSS) assembly, which includes a cylindrical reactor support structure, collector cylinder, divider wall, and exhaust ducts, allows for seismic isolation of the reactor enclosure system while optimizing cooling by directing working fluid through a riser annulus and downcomer annulus, and includes a flexible duct to connect seismically isolated and non-isolated portions of the reactor cooling system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reinforced concrete structure is used for the reactor building to provide seismic isolation, then seismic protection is improved, but construction cost and complexity increase
Solution Approach 1:
The reactor building is divided into a seismically isolated portion (containing the reactor enclosure system supported by seismic isolators) and a non-isolated portion (containing the exhaust system). This segmentation allows the critical reactor components to be protected while the exhaust system remains structurally simple and easier to construct, resolving the contradiction between seismic protection and construction complexity.
2Strength
If a thick concrete floor structure is used to provide structural support and containment, then structural strength is improved, but cooling efficiency deteriorates due to reduced heat transfer
Solution Approach 1:
The exhaust system is extracted from the seismically isolated portion and placed in a non-isolated portion of the reactor building. This allows the floor structure to be optimized for structural strength in the isolated portion without the constraint of accommodating thick concrete floors for exhaust containment, while cooling efficiency is maintained in the non-isolated exhaust portion where thermal performance can be prioritized.
3Strength
If the exhaust duct is positioned beneath a thick concrete floor, then structural containment is improved, but cooling efficiency deteriorates due to increased vertical spacing from the reactor
Solution Approach 1:
The exhaust duct system is taken out from beneath the thick concrete floor of the seismically isolated portion and repositioned in the non-isolated portion of the reactor building. This extraction resolves the conflict by allowing the isolated portion to have optimal structural containment with its thick floor, while the exhaust system operates in a location where it can maintain closer proximity to the reactor for improved cooling efficiency.
4Reliability
If the exhaust portion is included in the seismically isolated portion, then containment integrity is improved, but structural load on seismic isolators increases
Solution Approach 1:
The reactor building is segmented into seismically isolated and non-isolated portions, with the heavy exhaust system placed in the non-isolated portion. This segmentation transfers the weight of the exhaust system away from the seismic isolators, reducing their structural load while maintaining containment integrity through the segregated design where the isolated portion focuses solely on protecting the reactor enclosure system.
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 MIRSS assembly reduces construction costs and complexity, enhances seismic protection, and improves cooling efficiency by reducing structural loads and maintaining effective heat removal, allowing for increased operating temperatures and improved reactor performance.
Implementation Method 1
direct working fluid to flow downwards through the downcomer annulus to a bottom opening of the downcomer annulus, from the bottom opening of the downcomer annulus to a bottom opening of the riser annulus, upwards through the riser annulus to a top of the riser annulus according to a change in air density based on the working fluid absorbing heat
Implementation Method 2
upwards through the riser annulus to a top of the riser annulus according to a change in air density based on the working fluid absorbing heat from both the guard vessel and the collector cylinder
Implementation Method 3
a plurality of seismic isolators coupled to the reactor building, and a Modular Isolated Reactor Support System (MIRSS) assembly that is configured to structurally support the reactor enclosure system on the plurality of seismic isolators such that the MIRSS assembly defines a seismically isolated assembly within the nuclear plant that includes the reactor enclosure system and is seismically isolated from the reactor building
Data Source
AI summary
A Modular Isolated Reactor Support System (MIRSS) assembly includes a cylindrical reactor support structure configured to structurally support a reactor enclosure system on seismic isolators, a collector cylinder configured to at least partially define a riser annulus between an inner cylindrical surface of the collector cylinder and an outer sidewall surface of the reactor enclosure system structurally supported by the cylindrical reactor support structure, and a divider wall configured to at least partially define a downcomer annulus between an outer cylindrical surface of the divider wall and a reactor building, and a plurality of exhaust ducts extending from the collector cylinder and through an interior of the cylindrical reactor support structure.