Segmented Dry Conversion Reactor for Uranium Dioxide

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Solution Overview

Problem

Current dry conversion reactors for uranium hexafluoride to uranium dioxide are inflexible, requiring costly and time-consuming welding for modifications, limiting capacity and enrichment capabilities, and prone to cracking due to material incompatibilities, making upgrades expensive and difficult.

Innovation Solution

The implementation of a dry conversion reactor with replaceable segments, such as flanged configurations, allows for easy modification and maintenance, enabling changes in capacity and enrichment without welding, using pre-designed segments for the gas-phase and fluidized bed sections, and heat treatment of replaced segments to restore original properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-piece welded reactor design is used, then structural integrity is maintained, but modification and maintenance become costly and time-consuming

Engineering Contradiction:
Improveease of modificationVSAvoidtime for modifications
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The reactor is divided into multiple replaceable segments (gas-phase reaction segment, fluidized bed segment, transition segments, plenum segments) that can be independently removed and replaced. This segmentation allows modifications to be made by simply swapping segments rather than welding new sections onto an aged reactor, eliminating the need for costly and time-consuming welding operations on thermal-cycled materials.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If fixed geometry sections are used, then structural stability is maintained, but capacity and enrichment changes become difficult

Engineering Contradiction:
Improvecapacity flexibilityVSAvoidreactor configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The reactor configuration becomes dynamic through the use of replaceable segments with different geometries. The gas-phase reaction segment and fluidized bed segment can be swapped to change capacity and enrichment capabilities. This allows the reactor to adapt to different operational requirements (up to 100% U-235 enrichment) without permanent structural modifications, balancing versatility with manageable complexity through standardized segment interfaces.

Inventive Principle:
Principle #15Dynamics

3Reliability

If welding is used for reactor modifications, then structural continuity is maintained, but cracking occurs due to material incompatibility

Engineering Contradiction:
Improvestructural integrityVSAvoidweld cracking
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the reactor into replaceable sections, the invention eliminates the need to weld new geometry sections onto aged, thermal-cycled reactor materials. Each segment can be independently manufactured from appropriate materials and heat-treated before installation, avoiding the creation of dissimilar metal welds that are prone to cracking. The segments connect through flanged or other non-welded joints that maintain structural integrity without the harmful effects of welding aged materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reactor segments are pre-manufactured and pre heat-treated to their final geometry and material properties before installation. This preliminary action ensures that each segment has the appropriate microstructure and mechanical properties for its service conditions, eliminating the need for post-installation heat treatment of welded joints and preventing the cracking that would otherwise occur from welding thermal-cycled materials.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If full reactor heat treatment is performed, then material properties are restored, but cost and time increase significantly

Engineering Contradiction:
Improvematerial propertiesVSAvoidheat treatment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The segmentation of the reactor allows each segment to be independently heat-treated during its manufacturing process before installation. This eliminates the need for costly and time-consuming heat treatment of the entire reactor assembly. Each segment can be heat-treated to its final geometry and material properties separately, significantly reducing the total time and cost while maintaining or improving material properties through optimized segment-specific heat treatment processes.

Inventive Principle:
Principle #1Segmentation

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 enables cost-effective and timely upgrades, maintaining high operating efficiency with minimal downtime, allowing for increased capacity and enrichment flexibility up to 100% U-235, reducing the risk of cracking and material incompatibility issues, and facilitating quick repairs and replacements.

Implementation Method 1

a gas-phase reaction section and a defluorination/agglomeration section which are fixed for running up to the enrichment level required in commercial light water reactors

Methodology Applied
Scientific EffectGas-phase reaction: Chemical Transport Reactions

Implementation Method 2

The UO2F2 is defluorinated and the UO2 is agglomerated in the lower portion of the reactor using a fluidized bed

Methodology Applied
Scientific EffectFluidized bed: Fluidisation

Data Source

PatentEP2499097B1Segmented reactors for capacity and enrichment changes in conversion of uranium hexaflouride to uranium dioxide
Publication Date: 2019.02.20 FRAMATOME ANP INC
  • EP2499097B1 patent drawingFigure 1a~1d
  • EP2499097B1 patent drawingFigure 2a~2d
  • EP2499097B1 patent drawingFigure 3a~3b

AI summary

A dry conversion reactor for converting uranium hexafluoride to uranium dioxide, the dry conversion reactor including a gas-phase reaction segment and a fluidized bed segment, wherein at least one of the gas-phase reaction segment and the fluidized bed segment is a replaceable segment. A method for operating a dry conversion reactor utilizing a uranium hexafluoride to uranium dioxide conversion process, the method including replacing at least one conversion reactor segment.