Butyraldehyde Oxime Anti-Nitrous Agent in Plutonium Reductive Back-Extraction
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Solution Overview
Problem
The reductive stripping of plutonium from an organic phase to an aqueous phase in nuclear fuel reprocessing is hindered by the inability of existing anti-nitrous agents like hydrazine to prevent reoxidation of plutonium(III) to plutonium(IV), leading to significant reagent consumption and operational constraints due to the agent's inextractability in the solvent phase.
Innovation Solution
The use of butyraldehyde oxime as an anti-nitrous agent, which is extractable in the solvent phase and effectively blocks the reoxidation of plutonium(III) to plutonium(IV), reducing the need for uranium nitrate and hydrazine and simplifying the reductive plutonium stripping operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrazine is used as an anti-nitrous agent in the aqueous phase, then nitrous acid destruction is achieved, but significant reagent consumption occurs and reoxidation of plutonium(III) to plutonium(IV) cannot be prevented in the solvent phase
Solution Approach 1:
Butyraldehyde oxime acts as an intermediary substance that transfers from the aqueous phase to the solvent phase, where it directly prevents plutonium(III) reoxidation. This mediator approach eliminates the need for large excesses of uranium nitrate and hydrazine, reducing reagent consumption while maintaining reliable prevention of reoxidation.
Solution Approach 2:
The invention changes the chemical parameter of the anti-nitrous agent from hydrazine (water-soluble) to butyraldehyde oxime (organic-soluble). This parameter change allows the anti-nitrous agent to be present in the solvent phase where plutonium reoxidation occurs, fundamentally improving prevention reliability while reducing overall reagent consumption.
2Object-generated harmful factors
If hydrazine is used as anti-nitrous agent, then nitrous acid is destroyed in aqueous phase, but additional operational constraints are imposed due to azohydric acid formation and explosiveness risks
Solution Approach 1:
Butyraldehyde oxime serves as an intermediary that prevents the formation pathway of azohydric acid by blocking plutonium reoxidation in the solvent phase. This eliminates the harmful azohydric acid generation step, thereby removing the associated operational constraints and safety concerns regarding explosiveness.
Solution Approach 2:
The invention converts the harmful effect of nitrous acid (which leads to azohydric acid formation) into a beneficial outcome by using butyraldehyde oxime to prevent the intermediate reoxidation step. This eliminates the harmful azohydric acid pathway entirely, transforming a potentially dangerous process into a safer operation.
3Object-generated harmful factors
If hydrazine is used as anti-nitrous agent, then nitrous acid destruction is achieved, but additional sodium supply is required for neutralization which conflicts with glass vitrification specifications
Solution Approach 1:
Butyraldehyde oxime acts as an intermediary that prevents azohydric acid formation by blocking plutonium reoxidation. This eliminates the need for sodium neutralization, thereby preventing additional sodium from entering the waste stream and avoiding conflicts with glass vitrification specifications.
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
Butyraldehyde oxime significantly reduces reagent consumption, eliminates operational constraints, and increases the plutonium concentration factor, simplifying equipment design and operation by preventing reoxidation in the solvent phase.
Implementation Method 1
The presence of plutonium(III) in the solvent phase, even in small quantities, catalyzes the oxidation of uranous nitrate through the first two reactions and thereby generates nitrous acid. Butyraldehyde oxime blocks this reoxidation process.
Implementation Method 2
The reduction of plutonium(IV) to plutonium(III) is induced by a reducing agent which is added to the aqueous phase. The reducing agent used to extract the plutonium during the partitioning of the U/Pu flows is the uranous nitrate or U(IV).
Implementation Method 3
The reaction of destruction of nitrous acid by hydrazine only takes place in the aqueous phase. The azohydric acid formed by the reaction of destruction of nitrous acid by hydrazine reacts in turn with nitrous acid.
Implementation Method 4
passing this element from an organic phase (or solvent phase), in which it is at the oxidation state (IV), into an aqueous phase
Data Source
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Figure 3~4
AI summary
The invention relates to the use of butyraldehyde oxime as anti-nitrous agent in an operation for back-extracting plutonium based on a reduction of this element, from oxidation state (IV) to oxidation state (III). Applications: any method of reprocessing spent nuclear fuel in which the use of a compound having the two properties of being extractable in organic phase and capable of destroying the nitrous acid therein may be useful, and in particular to all those methods that comprise one or more operations for the reducing back-extraction of plutonium.