Metallurgically Incompatible Slotted Plates for Nuclear Fuel Storage
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Solution Overview
Problem
Current fuel rack designs for storing nuclear fuel assemblies require separate neutron absorber panels, which are structurally inefficient and limited by the amount of boron that can be introduced in stainless steel, necessitating a design that eliminates the need for these panels while maintaining safety and structural integrity.
Innovation Solution
A fuel rack design utilizing slotted plates made from metallurgically incompatible materials, where one material provides strength and the other serves as a neutron absorber, forming an array of cells with a base plate and tie members to ensure stability and safety, eliminating the need for separate absorber panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate neutron absorber panels are used in fuel rack designs, then neutron capture capability is provided, but structural efficiency deteriorates and design complexity increases
Solution Approach 1:
The patent combines the structural function and neutron absorption function into a single integrated component. The slotted plate structure incorporates neutron absorber material directly within the structural elements, eliminating the need for separate neutron absorber panels while maintaining both structural integrity and neutron capture capability.
Solution Approach 2:
The slotted plate design serves multiple functions simultaneously: it provides structural support for the fuel assemblies, acts as a neutron absorber through incorporated boron-containing materials, and facilitates water circulation for cooling. This multi-functionality reduces the overall number of components needed in the fuel rack system.
2Device complexity
If borated stainless steel is used to eliminate separate absorber panels, then design complexity is reduced, but the quantity of boron that can be introduced is limited by the stainless steel grain structure
Solution Approach 1:
The patent employs composite materials consisting of stainless steel combined with boron-containing materials (such as boron carbide or boron impregnated polymers) within the slotted plate structure. This composite approach allows significantly higher boron content than can be achieved through stainless steel alone, while maintaining the structural benefits of the stainless steel framework.
Solution Approach 2:
The slotted plate design incorporates porous or void-filled structures where boron-containing materials can be introduced and distributed throughout the plate thickness. This porous structure allows for high boron loading without compromising the overall structural integrity, as the boron-rich material fills the void spaces within the slotted plate configuration.
3Strength
If slotted plates made from metallurgically incompatible materials are used, then structural strength and neutron absorption are optimized, but manufacturing complexity increases
Solution Approach 1:
The fuel rack is divided into modular slotted plate units that can be manufactured separately from standardized materials and then assembled together. This segmentation allows each component to be optimized for its specific function (structural strength or neutron absorption) using appropriate materials, while the modular assembly simplifies the overall manufacturing process compared to creating a monolithic structure from incompatible materials.
Solution Approach 2:
The patent employs intermediate joining methods such as mechanical fasteners, welding with specialized filler materials, or bonding agents that can join metallurgically incompatible materials. These intermediary joining techniques enable the integration of different materials (e.g., stainless steel and boron-containing materials) while maintaining structural integrity at the joints.
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 simplifies the fuel rack structure, enhances safety by ensuring long-term nuclear fuel storage, and provides necessary structural and neutron absorption capabilities without the limitations of traditional designs.
Implementation Method 1
The neutron absorber is typically made of a metal matrix composite such as aluminum and boron carbide, the boron serving to capture the thermalized neutrons emitted by the fuel to control reactivity.
Implementation Method 2
The slotted plates are constructed from two different types of materials which are metallurgically incompatible, one which provides strength to the array of cells
Data Source
AI summary
A fuel rack for nuclear fuel assemblies includes a base plate and an array of cells for holding fuel assemblies. The array of cells includes: a plurality of first slotted plates slidably interlocked with one another to form a top portion of the array of cells, the plurality of first slotted plates formed of a first material; a plurality of second slotted plates slidably interlocked with one another to form a middle portion of the array of cells, the plurality of second slotted plates formed of a second material, the first and second materials being metallurgically incompatible; and a plurality of third slotted plates slidably interlocked with one another to form a bottom portion of the array of cells, the plurality of third slotted plates formed of the first material and connected to a top surface of the base plate.