Cryogenic Powder Mixing Device for Actinide Homogeneity
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Solution Overview
Problem
Current methods for mixing actinide powders to form nuclear fuel pellets are inadequate in achieving high homogeneity, often resulting in macroscopic defects, pollution, radiological risks, and inefficient energy use, particularly due to the limitations of dry powder metallurgy and existing mixer technologies which fail to deagglomerate effectively and induce contamination or radiolysis.
Innovation Solution
A device utilizing a cryogenic fluid, such as liquefied nitrogen, to deagglomerate and mix actinide powders with a gyroscopic movement and multiple mixing chambers, along with electrostatic charging and passage-restricting systems, to achieve high homogeneity and minimize energy consumption and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry powder metallurgy methods are used for mixing actinide powders, then the process avoids liquid effluent generation, but the mixing homogeneity is insufficient and macroscopic defects occur
Solution Approach 1:
A cryogenic fluid (liquefied gas) is introduced as an intermediary medium between the actinide powders. This fluid temporarily wets the powders during mixing, enabling effective deagglomeration and homogeneous distribution without using conventional liquids that would generate polluting effluents. The cryogenic fluid evaporates after mixing, leaving no residue.
Solution Approach 2:
The mixing process utilizes cryogenic temperatures to change the physical state and properties of the fluid medium. By operating at low temperatures, the fluid maintains a liquid state for effective mixing then evaporates completely, transforming the mixing mechanism from dry friction-based to fluid-based deagglomeration without permanent contamination.
2Manufacturing precision
If conventional mixers are used, then the device structure is simple, but the deagglomeration effectiveness is insufficient
Solution Approach 1:
The mixing chamber is divided into multiple zones with different flow characteristics and agitation intensities. The cryogenic fluid flow is segmented into controlled injection points and circulation paths, allowing different regions of the powder bed to experience optimized mixing conditions for effective deagglomeration.
Solution Approach 2:
The system uses pneumatic principles by introducing cryogenic gas or liquid through controlled flow rates and pressures. The fluid dynamics of the cryogenic medium create turbulent flow patterns that effectively break up agglomerates, replacing mechanical mixing elements with fluid-based deagglomeration forces.
3Manufacturing precision
If liquid methods are used for mixing powders, then mixing homogeneity improves, but effluent generation and pollution occur
Solution Approach 1:
The cryogenic fluid serves as an inert medium that does not chemically react with the actinide powders. After mixing, the fluid can be safely evaporated or contained without creating polluting effluents, as it leaves no chemical residue or requires minimal treatment compared to conventional liquid methods.
Solution Approach 2:
The cryogenic fluid undergoes phase transition from liquid to gas during or after the mixing process. This allows the fluid to perform its mixing function in liquid form then be easily removed as vapor, avoiding the need to manage liquid waste effluents while maintaining the benefits of liquid-based mixing homogeneity.
4Productivity
If traditional mixing methods are used, then the process is simple, but energy consumption is high and mixing time is long
Solution Approach 1:
The cryogenic fluid is introduced in controlled periodic pulses rather than continuous flow. This allows the fluid to mix effectively during each pulse, then the system pauses for evaporation or preparation of the next pulse, reducing overall energy consumption while maintaining mixing efficiency through repeated cycles of fluid injection and evaporation.
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 effectively deagglomerates powders, achieves high homogeneity, reduces radiological risks, and minimizes energy expenditure, allowing for continuous operation while preventing pollution and radiolysis, with a mixing time significantly shorter than traditional methods.
Implementation Method 1
mixing of actinide powders allowing for the formation of nuclear fuel, in particular pellets of nuclear fuel, through a cryogenic fluid, also called a cryogenic media
Implementation Method 2
Device for mixing powders by cryogenic fluid... mixing of actinide powders... through a cryogenic fluid
Implementation Method 3
along with electrostatic charging and passage-restricting systems, to achieve high homogeneity
Implementation Method 4
A device utilizing a cryogenic fluid, such as liquefied nitrogen, to deagglomerate and mix actinide powders with a gyroscopic movement
Data Source
AI summary
A device for mixing powders by cryogenic fluid, characterised in that it comprises at least: a chamber for mixing powders, comprising a cryogenic fluid; a chamber for supplying powders in order to allow the powders to be introduced into the mixing chamber; means for agitation in the mixing chamber so as to allow the mixing of the powders placed in suspension in the cryogenic fluid.