Cyclic Amine Monoamides for Single-Cycle Uranium Plutonium Separation
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Solution Overview
Problem
Current spent nuclear fuel treatment methods, such as PUREX, require multiple cycles and the use of tri-n-butyl phosphate, which necessitates plutonium reduction and generates safety concerns due to the need for large amounts of reducing and nitrous agents, limiting simplicity, compactness, and safety in future treatment plants.
Innovation Solution
The use of cyclic amine monoamides, specifically monoamides of formula (I), for extracting and separating uranium(VI) and plutonium(IV) from acidic aqueous solutions without reducing plutonium(IV), allowing for quantitative co-extraction and subsequent separation in a single cycle without plutonium reduction, using liquid-liquid extraction with an organic diluent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tri-n-butyl phosphate (TBP) is used as extractant in PUREX method, then uranium(VI) and plutonium(IV) can be recovered from aqueous solutions, but plutonium(IV) must be reduced to plutonium(III) which requires large amounts of reducing and anti-nitrous agents, generating safety concerns
Solution Approach 1:
The patent changes the chemical parameter of the extractant from TBP to cyclic amine monoamides (formula I), which fundamentally alters the extraction mechanism. This parameter change enables separation of uranium and plutonium without requiring reduction of plutonium, thereby eliminating the need for large amounts of reducing agents and improving safety while simplifying the process
Solution Approach 2:
The patent extracts only the essential function of separating uranium and plutonium using cyclic amine monoamides, removing the unnecessary step of plutonium reduction. The extractant selectively extracts uranium(VI) and plutonium(IV) into the organic phase, allowing direct separation without chemical reduction, thus eliminating safety concerns related to reducing agents
2Productivity
If TBP is used for partitioning uranium and plutonium into two aqueous flows, then separation can be achieved, but multiple cycles are required which limits simplicity and productivity
Solution Approach 1:
The patent merges the extraction and separation functions into a single operation using cyclic amine monoamides. Both uranium(VI) and plutonium(IV) are extracted into the organic phase in one step, and then separated by controlling the aqueous phase acidity, eliminating the need for multiple sequential cycles and improving productivity while reducing processing time
Solution Approach 2:
The patent performs preliminary co-extraction of both uranium and plutonium into the organic phase before separation. This preliminary action allows subsequent separation to be achieved simply by adjusting acidity conditions, avoiding the need for multiple extraction cycles and reducing overall processing time
3Measurement precision
If TBP extractant is used, then uranium and plutonium can be extracted, but the separation factor between uranium(VI) and plutonium(IV) is insufficient requiring additional reduction steps
Solution Approach 1:
The patent changes the extractant parameter from TBP to cyclic amine monoamides with specific structural features (formula I). This parameter change provides superior separation factors between uranium(VI) and plutonium(IV) by exploiting differences in their complexation behavior with the cyclic amine monoamide, enabling clear separation without additional reduction steps and maintaining operational simplicity
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 simplifies the process, eliminates the need for plutonium reduction, enhances safety, and achieves effective decontamination of uranium and plutonium in a single cycle, with improved handling and reduced waste production, suitable for both uranium and plutonium oxides-based fuels.
Implementation Method 1
uranium(VI) and/or plutonium(IV) are extracted from the aqueous solution by liquid-liquid extraction
Data Source
AI summary
Uses of cyclic amine monoamides for extracting uranium(VI) and/or plutonium(IV) from an acidic aqueous solution, as well as for totally or partially separating uranium(VI) from plutonium(IV) from an acidic aqueous solution. A method for treating an aqueous solution resulting from the dissolution of spent nuclear fuel in nitric acid to extract, separate and decontaminate uranium(VI) and plutonium(IV) in a single cycle and without resorting to any operation of reducing plutonium(IV), and wherein a cyclic amine monoamide or a mixture of cyclic amine monoamides is used as extractant. The cyclic amine monoamides have formula (I):