Cold Sprayed LEU-Al Fuel Core for Mo-99 Recovery
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Solution Overview
Problem
Nuclear fuel products using low-enriched uranium (LEU) result in lower molybdenum-99 recovery and neutron emission compared to highly enriched uranium (HEU), and the manufacturing process of these products leads to geometrical deformations and cladding failures due to thermal treatment.
Innovation Solution
A method of producing a nuclear fuel product with a core comprising low-enriched uranium and aluminum, where the uranium loading is higher than 3.0 gU/cm3 and the aluminum phase content is less than 10 wt %, using a cladding made from materials like zirconium or stainless steel, and the core consists predominantly of UAl3 and UAl4 phases, with a higher proportion of UAl3, to enhance uranium density and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low-enriched uranium (LEU) is used instead of highly enriched uranium (HEU), then nuclear proliferation risk is reduced, but molybdenum-99 recovery and neutron emission decrease
Solution Approach 1:
The patent changes the chemical composition parameters of the nuclear fuel core by using UAl2 phase particles instead of traditional UAl3 or UAl4 particles. This phase change enables higher uranium density (strictly higher than 3.0 gU/cm3) while maintaining LEU enrichment, thereby resolving the contradiction between proliferation risk reduction and Mo-99 production efficiency
Solution Approach 2:
The patent creates a composite material structure consisting of UAl2 phase particles dispersed in an aluminum matrix with controlled composition (less than 10 wt% aluminum phase and/or aluminum compounds). This composite approach optimizes both the nuclear performance and physical properties of the fuel core, enabling high uranium loading with LEU
2Stability of the object's composition
If thermal treatment is applied to convert UAl2 phase into UAlx phase, then phase stability is improved, but geometrical deformations and cladding failures increase
Solution Approach 1:
The patent performs preliminary alloying during core fabrication to directly create the desired UAl2, UAl3, and UAl4 phase composition without requiring subsequent thermal treatment for phase conversion. By preparing the core with the target phase distribution upfront, the patent avoids the geometrical deformations and cladding failures that would result from post-fabrication thermal processing
Solution Approach 2:
The patent extracts or eliminates the thermal treatment step from the manufacturing process. Instead of using thermal treatment to convert UAl2 to UAlx phases, the method directly produces the desired phase composition during core fabrication, thereby removing the source of geometrical deformations and cladding failures
3Productivity
If uranium loading is increased to compensate for lower enrichment, then Mo99 recovery is improved, but manufacturing complexity and cladding failure risk increase
Solution Approach 1:
The patent changes the material parameters by utilizing UAl2 phase particles which provide higher uranium density. This allows achieving the required uranium loading (strictly higher than 3.0 gU/cm3) with a simpler manufacturing process that does not require complex thermal treatments or multiple processing steps, thereby improving Mo-99 recovery without proportionally increasing manufacturing complexity
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 method achieves improved molybdenum-99 recovery and higher neutron emission while reducing the risk of cladding failures and geometrical deformations, allowing for a cost-effective and stable nuclear fuel product with enhanced uranium loading.
Implementation Method 1
the particles mostly containing the UAl2 phase, which provides a higher uranium-alloy density than both UAl3 and UAl4, hence a higher U235 content to compensate the lower U235 enrichment of the uranium
Implementation Method 2
The nuclear fuel product, after being rolled, undergoes a thermal treatment in order to convert the UAl2 phase into UAlx in the core, with x above or equal to 3 by using part of the Al matrix
Implementation Method 3
Method for producing nuclear fuel products by cold spraying a core comprising aluminum and low enriched uranium
Data Source
AI summary
A method of producing a nuclear fuel product includes the steps of providing a core comprising aluminium and low-enriched uranium; and sealing said core in a cladding. The low-enriched uranium has a proportion of U235 below 20 wt %. The step of providing the core including melting low-enriched uranium and aluminium in a furnace to form a melt of uranium-aluminium alloy, producing a powder from the melt of uranium-aluminium alloy, and cold-spraying the powder on a surface of the cladding.