Phosphoric Acid Electrolyte for Radioactive Decontamination
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Solution Overview
Problem
Current electrochemical decontamination methods for radioactively contaminated stainless steel scrap face challenges due to the lack of a suitable electrolyte, resulting in poor decontamination effects and difficult treatment of secondary waste solutions, with existing electrolytes often being incompatible with radioactive waste treatment systems and generating transuranic waste.
Innovation Solution
An electrolyte composed of phosphoric acid, oxalic acid, citric acid, tartaric acid, hydrogen peroxide, and glacial acetic acid is used for electrochemical decontamination, which promotes effective removal of contamination layers on stainless steel and facilitates easy treatment of secondary waste solutions by forming iron phosphate glass, reducing the need for electrolyte replacement and minimizing radioactive contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nitric acid system electrolyte is used for electrochemical decontamination, then decontamination effect is improved, but waste solution treatment becomes difficult and transuranic waste may form
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by replacing nitric acid with phosphoric acid as the main component and adding specific organic acids (oxalic, citric, tartaric) and hydrogen peroxide in controlled concentrations. This parameter change maintains decontamination effectiveness while producing waste solution compatible with glass solidification treatment, eliminating the transuranic waste formation problem associated with nitric acid systems.
2Manufacturing precision
If sulfuric acid or hydrochloric acid electrolyte is used, then decontamination ability is improved, but waste solution is incompatible with solidification system
Solution Approach 1:
The patent changes the electrolyte composition from sulfuric acid or hydrochloric acid-based systems to a phosphoric acid-based system with specific organic acid additives. This parameter change achieves high decontamination ability while ensuring the waste solution contains no sulfate or chloride ions that would interfere with glass solidification, thus achieving full compatibility with the solidification treatment system.
3Manufacturing precision
If high concentration sodium phosphate electrolyte is used, then decontamination effect is improved, but welded joints are preferentially oxidized causing structural damage
Solution Approach 1:
The patent changes the electrolyte composition by using phosphoric acid with controlled concentration (40-80% by volume) combined with specific concentrations of organic acids and hydrogen peroxide. This parameter optimization provides sufficient decontamination effect while the presence of organic acids and controlled oxidizing environment prevents preferential oxidation of welded joints, preserving structural integrity.
Solution Approach 2:
The patent creates a composite electrolyte system combining phosphoric acid (inorganic acid) with multiple organic acids (oxalic, citric, tartaric) and hydrogen peroxide. This composite composition works synergistically to provide effective decontamination while the organic acids protect welded joints from preferential oxidation, resolving the contradiction between decontamination effectiveness and structural protection.
4Duration of action of moving object
If electrochemical decontamination is performed with existing electrolytes, then treatment duration is reduced, but electrolyte replacement frequency increases due to radioactive contamination
Solution Approach 1:
The patent changes the electrolyte composition to a phosphoric acid-based system with specific organic acid additives that create a more stable chemical environment. This parameter change maintains high decontamination efficiency (short treatment duration) while the enhanced stability of the electrolyte composition reduces radioactive contamination accumulation, thereby extending electrolyte service life and reducing replacement frequency.
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 proposed electrolyte achieves efficient decontamination of radioactively contaminated stainless steel with minimal secondary waste generation, allowing for easy treatment of resulting residues and reducing the risk of transuranic waste formation, thus enhancing the practicality and safety of the electrochemical decontamination process.
Implementation Method 1
Electrochemical decontamination is a new method that has developed rapidly in recent years. Its principle is to remove radioactive contamination on the surface of an electrically conductive material through electrochemical action.
Implementation Method 2
The electrochemical decontamination has the advantages of high decontamination ability, short treatment durations, low consumption of chemical reagents, and high removal efficiency for fixed contamination.
Data Source
AI summary
An electrolyte for electrochemical decontamination and a preparation method and application thereof. The electrolyte is an aqueous solution including the following solutes: phosphoric acid, oxalic acid, citric acid, tartaric acid, hydrogen peroxide and glacial acetic acid. The electrolyte has a good decontamination effect and allows for fast decontamination and is obtained by reasonably combining different types of solutes and controlling the levels of the solutes and resulting secondary waste solution and residues are easy to treat. The electrolyte is suitable for overall or local electrochemical decontamination of radioactively contaminated stainless steel scrap.