Cryogenic Atomization for Actinide Powder Granulation

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Solution Overview

Problem

Current methods for granulating actinide powders to produce nuclear fuel pellets face challenges such as inadequate homogeneity, contamination risks, radiological impacts, and inefficiencies in mixing and granulation processes, particularly due to the use of liquids and high energy requirements.

Innovation Solution

A device utilizing cryogenic atomization with a cryogenic fluid for mixing and granulating actinide powders, which includes a mixing enclosure with cryogenic fluid, an atomization system for adjusting droplet sizes, and humidity control, allowing for deagglomeration and granulation without liquid separation, thus minimizing contamination and energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If liquid/solid type mixers are used for mixing actinide powders, then mixing efficiency is improved, but contamination risks and radiological impacts increase due to liquid contact

Engineering Contradiction:

Improvemixing efficiencyVSAvoidcontamination risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent uses gas phase as an intermediary medium instead of liquid to mix actinide powders. The gas phase allows for effective mixing while avoiding contamination risks associated with liquid contact, as gases can be easily contained and do not leave residual contamination on the powders.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs an inert gas atmosphere (such as nitrogen or argon) for mixing actinide powders. This inert environment prevents oxidation and other chemical reactions while allowing efficient mixing, and the gas can be easily filtered and contained to minimize radiological impacts.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If traditional dry mixing methods are used for actinide powders, then contamination risks are reduced, but mixing homogeneity is insufficient

Engineering Contradiction:

Improvecontamination riskVSAvoidmixing homogeneity

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent uses gas phase mixing (pneumatic approach) to achieve both low contamination risk and high mixing homogeneity. The gas flow patterns and turbulence created during gas phase mixing enable thorough particle distribution and homogeneous mixing without the contamination issues of liquid-based methods.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Productivity

If liquid atomization is used for granulation, then granule formation is effective, but separation of liquid from granules requires additional energy-consuming drying steps

Engineering Contradiction:

Improvegranulation efficiencyVSAvoiddrying energy

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces liquid-based atomization with gas phase atomization. This substitution eliminates the need for energy-consuming drying steps because gases do not leave residual liquid that requires evaporation or drying. The gas phase atoms can be condensed or captured without thermal processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of gas to solid (deposition or condensation) instead of liquid evaporation. Gas phase atoms can directly deposit or condense to form granules without requiring the energy-intensive drying process needed for liquid-based atomization.

Inventive Principle:

Principle #36Phase transitions

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 approach achieves high homogeneity and deagglomeration of actinide powders, reduces contamination and radiological risks, and enables a continuous, efficient mixing process, producing granules suitable for nuclear fuel pellets with improved flowability and sinterability.

Implementation Method 1

a device for granulating powders by cryogenic atomization

Methodology Applied

Scientific EffectCryogenic condensation: Condensation

Implementation Method 2

mixing powders using cryogenic fluid

Methodology Applied

Scientific EffectCryogenic cooling: Cooling

Implementation Method 3

means for fractionating the powder suspension enabling adjustment of the size of the droplets of powder suspension to be atomized

Methodology Applied

Scientific EffectAtomization:

Data Source

PatentEP3370857B1Device for granulating powders by cryogenic atomisation

Publication Date: 2025.01.01 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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AI summary

The invention relates mainly to a device (20) for granulating powders (P) by cryogenic atomisation, characterised in that it comprises: a device (1) for mixing powders (P) by cryogenic fluid (FC), comprising at least one chamber (E1) for mixing powders (P), comprising a cryogenic fluid (FC); and a device (10) for atomising a suspension of powders (P) mixed by the device (1) for mixing powders (P) in order to allow a granulation of the powders (P), comprising means for fractionating the suspension of powders (P) making it possible to adjust the size of the droplets (Go) of powders (P) to be atomised, and means for adjusting the moisture of the mixed powders (P) and/or the moisture of the atomisation atmosphere.