Uranium Carbide Stabilization via Controlled Isothermal Oxidation

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Solution Overview

Problem

Current stabilization processes for uranium carbide compounds UCx are inadequate as they often result in uncontrolled thermal runaway, excessive gaseous effluents, and prolonged treatment times, failing to meet nuclear safety standards for storage and waste management.

Innovation Solution

A controlled isothermal oxidation process between 380°C and 550°C under partial O2 pressure, monitoring oxygen consumption and CO/CO2 release, with optional H2O vapor introduction to ensure complete stabilization of UCx into UOx without oxidizing excess graphite, using a device with real-time gas analysis and temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If oxidation temperature is increased to accelerate UCx conversion to UOx, then productivity improves, but thermal runaway risk increases

Engineering Contradiction:
Improveoxidation rateVSAvoidthermal stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling oxidation temperature within the range of 380-550°C, optimizing the balance between oxidation rate and thermal stability. This temperature window accelerates UCx conversion to UOx while preventing runaway reactions, resolving the contradiction between productivity and reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control through real-time monitoring of oxygen consumption and CO/CO2 evolution rates. This allows dynamic adjustment of oxidation conditions to maintain safe operation while maximizing conversion efficiency, addressing both productivity and thermal stability requirements

Inventive Principle:
Principle #23Feedback

2Stability of the object's composition

If oxidation is performed to stabilize UCx, then chemical stability improves, but gaseous effluents increase

Engineering Contradiction:
Improvechemical stabilityVSAvoidgaseous effluents
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by selectively oxidizing only the UCx phase while preserving excess graphite carbon through controlled temperature management. This selective oxidation achieves complete stabilization of UCx to UOx while minimizing CO2 generation from graphite, resolving the contradiction between chemical stability and effluent production

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By optimizing oxidation temperature parameters (380-550°C) and atmospheric composition, the patent enables selective oxidation of UCx without oxidizing excess graphite. This parameter control achieves complete stabilization while minimizing harmful gaseous effluents

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional oxidation methods are used, then treatment is simpler, but treatment time increases

Engineering Contradiction:
Improveprocess simplicityVSAvoidtreatment time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent implements continuous oxidation treatment with optimized atmospheric control and temperature maintenance, eliminating idle periods and ensuring continuous conversion of UCx to UOx. This continuous process reduces treatment time while maintaining operational simplicity through automated control systems

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

By optimizing key parameters including temperature (380-550°C), oxygen partial pressure, and treatment atmosphere composition, the patent accelerates oxidation kinetics significantly. These parameter optimizations reduce treatment time from conventional extended periods to optimized cycles, while maintaining process simplicity through controlled parameter management

Inventive Principle:
Principle #35Parameter changes

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 process stabilizes UCx into UOx safely and efficiently, minimizing gaseous effluents, preventing thermal runaway, and reducing treatment time, while ensuring compatibility with nuclear safety standards and semi-industrial requirements.

Implementation Method 1

an isothermal oxidation treatment step at said oxidation temperature, said enclosure being placed under partial pressure of O2

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a step of raising the temperature of the internal temperature of the said enclosure to a temperature called oxidation temperature

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2737494B1Method for chemically stabilizing uranium carbide compounds, and device implementing the method
Publication Date: 2015.08.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2737494B1 patent drawingFigure 1
  • EP2737494B1 patent drawingFigure 2
  • EP2737494B1 patent drawingFigure 3

AI summary

The invention relates to a method for chemically stabilizing a uranium carbide compound having the formula UCx + yC, where x = 1 or 2, and y > 0, x and y being real numbers, placed in a stabilization chamber, characterized in that it includes the following steps: a step of raising the internal temperature of said chamber to a so-called oxidization temperature for oxidizing said uranium carbide compound, which is between around 380°C and 550°C, said chamber being supplied with an inert gas; a step of isothermal oxidization treatment at said oxidization temperature, said chamber being placed under partial pressure of O2; and a step of checking for the completion of the stabilization of said compound, said step including tracking the amount of consumed dioxygen, and/or carbon dioxide, or carbon dioxide and carbon monoxide released until an input set value for said amount of dioxygen, a minimum threshold value for said amount of carbon dioxide, or minimum threshold values for the carbon dioxide and carbon monoxide, are reached. The invention also relates to a device for implementing the method.