Predicting Uranium Oxide Sintered Density via Ammonium Diuranate Chromaticity

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Solution Overview

Problem

Current methods for analyzing the sintered density of uranium oxide (UOx) powder in nuclear fuel manufacturing are limited to post-pelletizing processes, leading to complex and error-prone procedures, with no effective way to predict density before pelletizing, resulting in inefficient production and potential re-treatment needs.

Innovation Solution

Measuring the chromaticity of ammonium diuranate powder using a spectrophotometer and comparing the data with standard values to predict the sintered density of uranium oxide (UOx) before the pelletizing process, utilizing the L* a* b* color coordinate system for accurate calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sintered density is measured after the pelletizing process using electrical balance and water, then the measurement can be performed, but the pre- and post-treatment processes become very complicated and error rates increase

Engineering Contradiction:
Improvesintered density measurementVSAvoidmeasurement process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by measuring the chromaticity of ammonium diuranate powder before the pelletizing process. This allows the sintered density to be predicted in advance, eliminating the need for complex post-pelletizing measurements and their associated pre- and post-treatment procedures. The chromaticity measurement serves as an early indicator that can forecast the final sintered density without requiring the actual pelletizing and density measurement processes.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If sintered density is measured after pelletizing, then quality can be examined, but subsequent treatment processes must be repeated when density is out of range

Engineering Contradiction:
Improvequality examinationVSAvoidproduction cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent enables preliminary quality assessment by measuring chromaticity before pelletizing. This early measurement allows prediction of whether the sintered density will be within the specified range, enabling quality control decisions to be made before the pelletizing process begins. Consequently, if the chromaticity indicates out-of-range density, the issue can be addressed in the precursor stage rather than requiring time-consuming re-pelletizing and re-measurement cycles.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using chromaticity measurement results to predict and control sintered density. The chromaticity values obtained from ammonium diuranate powder serve as feedback information that can be used to adjust process parameters before pelletizing, ensuring the final product meets quality specifications without requiring iterative re-testing after pellet formation.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If conventional density measurement method is used, then sintered density can be determined, but the rate of occurrence of errors depends significantly on the person performing the analysis

Engineering Contradiction:
Improvesintered density determinationVSAvoidoperator dependency
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical and manual density measurement process with an optical measurement system. Instead of using electrical balance and water displacement methods that require manual operation and interpretation, the patent uses a spectrophotometer to measure chromaticity properties of the powder. This substitution eliminates operator-dependent errors in manual measurement and interpretation, as the chromaticity measurement provides objective, quantifiable data that can be directly correlated to sintered density through established relationships.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method allows for reliable prediction and analysis of sintered density during all stages of pelletizing, reducing analysis time by 97.5% compared to conventional methods and ensuring the production of optimal pellets, thereby simplifying the process and reducing errors.

Implementation Method 1

measuring the chromaticity of ammonium diuranate, which is a precursor of uranium oxide (UO x ), using a spectrophotometer

Methodology Applied
Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3282452B1Method of analyzing the sintered density of uranium oxide (UOX) using a spectrophotometer
Publication Date: 2019.01.09 KEPCO NUCLEAR FUEL CO LTD
  • EP3282452B1 patent drawingFigure 1
  • EP3282452B1 patent drawingFigure 2A~2B
  • EP3282452B1 patent drawingFigure 3~4

AI summary

Disclosed is a method of predicting, calculating, or analyzing the sintered density of uranium oxide (UOx) before uranium oxide is added in the pelletizing process during a process of manufacturing nuclear fuel, the method including measuring the chromaticity of ammonium diuranate using a spectrophotometer. The present invention provides a simple and highly reliable method of predicting the sintered density of uranium oxide (UOx), which overcomes the problem with a conventional technology where the sintered density of uranium oxide (UOx) can be analyzed only in a pellet state and a subsequent treatment process needs to be performed according to the analysis result.