CERMET Fuel Element with Integrated Coolant Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nuclear thermal propulsion (NTP) reactors face challenges in achieving specific impulse values of 800 to 1000 seconds, requiring high-assay low-enriched uranium (HALEU) fuels and complex fabrication of refractory metal-based CERMET fuel elements with integrated coolant channels.
Innovation Solution
A nuclear fission reactor structure incorporating a CERMET fuel element with ceramic fuel particles in a metal matrix, featuring distributed coolant channels and a structural refractory carbide layer, fabricated using a hot-isostatic pressing (HIP) process to consolidate ceramic fuel particles and channel blanks, enabling efficient heat transfer and thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HALEU fuel is used to achieve specific impulse values of 800 to 1000 seconds, then propulsion performance is improved, but fabrication complexity increases
Solution Approach 1:
The patent combines the fuel pellet and coolant channel into a single integrated CERMET fuel element. The ceramic fuel particles are embedded directly within the refractory metal matrix that forms the structural body containing the coolant channels, eliminating the need for separate assembly steps and reducing fabrication complexity while maintaining the required specific impulse performance
Solution Approach 2:
The patent employs CERMET (ceramic-metal) composite material where ceramic fuel particles (providing nuclear fission capability) are dispersed within a refractory metal matrix (providing structural integrity and coolant channel containment). This composite approach enables simultaneous achievement of high specific impulse through HALEU fuel and simplified fabrication through integrated monolithic structure
2Use of energy by moving object
If CERMET fuel elements with integrated coolant channels are fabricated, then heat transfer efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
The coolant channels are pre-formed within the refractory metal matrix before the ceramic fuel particles are embedded. This preliminary structuring of the metal matrix with integrated channels allows for efficient heat transfer pathways to be established ahead of time, while the subsequent fuel particle embedding completes the fabrication in a streamlined sequence
Solution Approach 2:
The CERMET composite structure integrates the coolant-containing metal matrix with fuel-bearing ceramic particles in a single monolithic element. The metal matrix provides continuous coolant flow paths for efficient heat extraction, while the ceramic particles distribute fuel throughout the structure, achieving both heat transfer efficiency and manufacturability through the composite architecture
3Productivity
If fuel temperatures exceed 2900K to achieve desired specific impulse, then propulsion efficiency is improved, but fuel structural integrity deteriorates
Solution Approach 1:
The ceramic fuel particles are embedded within a refractory metal matrix that serves as a structural carrier. The ceramic particles can withstand the high temperatures required for high specific impulse, while the refractory metal matrix provides mechanical strength and structural integrity at these elevated temperatures, enabling the composite to maintain integrity where either material alone would fail
Solution Approach 2:
Different regions of the fuel element have specialized functions: the ceramic fuel particles are positioned to undergo nuclear fission at high temperatures, while the surrounding refractory metal matrix is positioned to provide structural support and contain the coolant channels. This local differentiation of material properties allows the structure to simultaneously achieve high temperature operation and maintain structural integrity
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 enables the production of CERMET fuel elements that achieve the desired specific impulse range, facilitating the use of HALEU fuels and simplifying the fabrication process, thereby enhancing the performance and efficiency of NTP reactors.
Implementation Method 1
fabricated using a hot-isostatic pressing (HIP) process to consolidate ceramic fuel particles and channel blanks
Implementation Method 2
featuring distributed coolant channels and a structural refractory carbide layer, fabricated using a hot-isostatic pressing (HIP) process to consolidate ceramic fuel particles and channel blanks, enabling efficient heat transfer and thrust generation
Data Source
AI summary
CERMET fuel element includes a fuel meat of consolidated ceramic fuel particles (preferably refractory-metal coated HALEU fuel kernels) and an array of axially-oriented coolant flow channels. Formation and lateral positions of coolant flow channels in the fuel meat are controlled during manufacturing by spacer structures that include ceramic fuel particles. In one embodiment, a coating on a sacrificial rod (the rod being subsequently removed) forms the coolant channel and the spacer structures are affixed to the coating; in a second embodiment, a metal tube forms the coolant channel and the spacer structures are affixed to the metal tube. The spacer structures laterally position the coolant channels in spaced-apart relation and are consolidated with the ceramic fuel particles to form CERMET fuel meat of a fuel element, which are subsequently incorporated into fuel assemblies that are distributively arranged in a moderator block within a nuclear fission reactor, in particular for propulsion.