Silicon Carbide Foam TRISO Fuel Elements
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Solution Overview
Problem
Current nuclear fuel elements for high temperature gas-cooled reactors (HTGRs) and gas-cooled fast reactors (GFRs) lack efficient cooling and gas mobility, limiting thermal control and fuel density, as well as increasing fission product gas buildup and cladding stress, which reduces fuel lifetime and proliferation risk.
Innovation Solution
The development of porous nuclear fuel elements using a silicon carbide foam structure with hollow ligaments that allow for coolant flow close to the fuel particles, providing structural reinforcement and serving as network cooling passages, and for GFRs, using TRISO-like hollow ligaments to vent fission products, allowing for increased fuel density and efficient heat removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional nuclear fuel elements are used, then structural integrity is maintained, but cooling efficiency is insufficient and thermal gradients are high
Solution Approach 1:
The patent employs a porous foam structure with interconnected ligaments and pores that allows coolant to penetrate deeply into the fuel element interior. This porous architecture increases the effective heat transfer surface area and enables efficient cooling while maintaining structural integrity, directly resolving the contradiction between thermal gradient reduction and cooling efficiency.
Solution Approach 2:
The invention transitions from conventional two-dimensional cooling surfaces to a three-dimensional network of cooling passages formed by the foam ligaments. This dimensional expansion allows coolant to access fuel particles throughout the volume of the fuel element, dramatically improving cooling efficiency while reducing thermal gradients in all spatial directions.
2Productivity
If fuel density is increased, then power efficiency improves, but thermal control becomes more difficult
Solution Approach 1:
The porous foam structure enables increased fuel density by providing a framework that can accommodate higher concentrations of fuel particles within the ligaments and pores. Simultaneously, the interconnected porosity maintains excellent coolant flow paths, ensuring that thermal control is not compromised despite the increased fuel loading and power density.
3Weight of moving object
If conventional foam structures are used, then lightweight structure is achieved, but gas mobility is insufficient
Solution Approach 1:
The patent utilizes a highly porous foam structure with interconnected ligaments and open pores that provides excellent gas mobility. The porosity allows fission product gases to move freely through the fuel element structure for efficient venting, while the foam architecture maintains lightweight construction. This resolves the contradiction by demonstrating that porosity can simultaneously enable both lightweight design and high gas mobility.
4Duration of action of stationary object
If fuel lifetime is extended, then proliferation risk decreases, but fission product gas buildup increases cladding stress
Solution Approach 1:
The patent extracts fission product gases from the fuel element interior through the porous foam structure and venting pathways. By continuously removing these gases, the buildup that would otherwise increase cladding stress is prevented. This enables extended fuel lifetimes to be achieved without the detrimental accumulation of fission products, resolving the contradiction between fuel lifetime extension and cladding stress reduction.
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 enhances thermal conductivity, reduces thermal gradients, increases fuel density, and extends fuel lifetime by improving cooling efficiency and reducing fission product gas buildup, while minimizing proliferation risk and increasing power efficiency through efficient waste management.
Implementation Method 1
This design enhances thermal conductivity, reduces thermal gradients
Implementation Method 2
allowing for coolant flow close to the fuel particles, providing structural reinforcement and serving as network cooling passages, and for GFRs, using TRISO-like hollow ligaments to vent fission products, allowing for increased fuel density and efficient heat removal
Implementation Method 3
Active venting of fission product gases and the resultant decrease in cladding stress in TRISO fuel elements for GFRs
Data Source
AI summary
A nuclear fuel element is provided. The nuclear fuel element includes a porous support. The porous support includes a ligament and defines a pore adjacent to the ligament. The ligament has an interior surface spaced from the pore. The interior surface defines a void. The porous support includes silicon carbide. The nuclear fuel element includes a nuclear fuel material disposed in the pore. The nuclear fuel material includes a moderator and tri-structural isotropic (TRISO) particles. Another nuclear fuel element is provided. The nuclear fuel element includes a porous support. The porous support includes a ligament and defines a pore adjacent to the ligament. The ligament has an interior surface spaced from the pore. The interior surface defines a void. The ligament includes the nuclear fuel material. The nuclear fuel element includes a facesheet overlying the porous support and defines a hole. The hole is in fluid communication with the void. The nuclear fuel material includes a nuclear fuel.