Spent Nuclear Fuel Reprocessing Without Plutonium-Reducing Stripping
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Solution Overview
Problem
Current reprocessing methods for spent nuclear fuel, such as the PUREX and COEX processes, require complex plutonium-reducing stripping operations that pose operational constraints and safety risks, especially for MOX fuels with high plutonium content, due to the occurrence of redox reactions and the need for substantial reducing and anti-nitrous agents.
Innovation Solution
A process that decontaminates uranium and plutonium without requiring a plutonium-reducing stripping operation by using selective extraction of uranium in a nitric aqueous phase, allowing uranium to be transferred into an organic phase while keeping plutonium in the aqueous phase, thereby eliminating the need for reducing reactions and simplifying the partitioning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plutonium-reducing stripping operation is used to partition uranium and plutonium, then the purification and separation of uranium and plutonium is achieved, but the process complexity increases and safety risks arise due to redox reactions and the need for substantial reducing and anti-nitrous agents
Solution Approach 1:
The invention changes the oxidation state parameter of plutonium from IV to III through reduction, enabling selective transfer to aqueous phase. This parameter change allows partitioning without complex multi-cycle operations, simplifying the overall process while maintaining high purification precision.
Solution Approach 2:
The invention uses an intermediary aqueous phase as a mediator to transfer plutonium from the organic phase. By introducing this intermediate aqueous phase containing reducing agents, the process achieves separation without requiring complex stripping operations, reducing process complexity while maintaining separation efficiency.
2Manufacturing precision
If a plutonium-reducing stripping operation is used to partition uranium and plutonium, then the purification and separation of uranium and plutonium is achieved, but safety risks increase due to redox reactions and the need for substantial reducing and anti-nitrous agents
Solution Approach 1:
The invention changes the oxidation state parameter of plutonium from IV to III through reduction, enabling selective transfer to aqueous phase. This parameter change allows partitioning without complex multi-cycle operations, simplifying the overall process while maintaining high purification precision.
Solution Approach 2:
The invention uses an intermediary aqueous phase as a mediator to transfer plutonium from the organic phase. By introducing this intermediate aqueous phase containing reducing agents, the process achieves separation without requiring complex stripping operations, reducing process complexity while maintaining separation efficiency.
3Manufacturing precision
If a plutonium-reducing stripping operation is used, then uranium and plutonium can be partitioned into two aqueous flows, but the quantity of reducing and anti-nitrous agents required increases substantially
Solution Approach 1:
The invention changes the oxidation state parameter of plutonium from IV to III through reduction, enabling selective transfer to aqueous phase. This parameter change allows partitioning without complex multi-cycle operations, simplifying the overall process while maintaining high purification precision.
Solution Approach 2:
The invention uses an intermediary aqueous phase as a mediator to transfer plutonium from the organic phase. By introducing this intermediate aqueous phase containing reducing agents, the process achieves separation without requiring complex stripping operations, reducing process complexity while maintaining separation efficiency.
4Manufacturing precision
If a plutonium-reducing stripping operation is used, then uranium and plutonium can be partitioned into two aqueous flows, but the process time and operational steps increase
Solution Approach 1:
The invention changes the oxidation state parameter of plutonium from IV to III through reduction, enabling selective transfer to aqueous phase. This parameter change allows partitioning without complex multi-cycle operations, simplifying the overall process while maintaining high purification precision.
Solution Approach 2:
The invention uses an intermediary aqueous phase as a mediator to transfer plutonium from the organic phase. By introducing this intermediate aqueous phase containing reducing agents, the process achieves separation without requiring complex stripping operations, reducing process complexity while maintaining separation efficiency.
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 enables efficient recovery and decontamination of uranium and plutonium without the complexities and safety concerns of plutonium-reducing stripping, offering flexibility in adjusting the plutonium-to-uranium ratio and simplifying the reprocessing steps, while maintaining the performance of existing processes.
Implementation Method 1
The extractant used is tri-n-butyl phosphate which has particular affinity for uranium and plutonium. This is obtained by implementing several purification cycles by liquid-liquid extraction.
Implementation Method 2
the organic phase containing the plutonium(IV) is contacted with a nitric aqueous phase which contains a reducing agent capable of reducing this plutonium(IV) to plutonium(III)
Data Source
AI summary
The invention relates to a process for reprocessing spent nuclear fuel which, among other advantages, does not require a plutonium-reducing stripping operation.This process finds particular application in the processing of uranium oxide fuels and uranium and plutonium mixed oxide fuels.