Electroreducer Electrorefiner Molten Salt Nuclear Fuel Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional facilities for processing nuclear fuel after a reactor accident, such as the Fukushima Daiichi accident, face challenges due to the introduction of foreign materials like sea salts, which can damage equipment and compromise the integrity of metal containers through corrosive action, making it difficult to stabilize and store nuclear materials effectively.
Innovation Solution
A method involving the use of an electroreducer with a molten salt electrolyte and a reducer cathode assembly to reduce nuclear materials, followed by an electrorefiner with a second molten salt electrolyte and refiner anode and cathode assemblies to produce purified metal products, effectively removing and stabilizing waste materials, including sea salts, through electrolytic reduction and refining processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional facilities are used to process nuclear fuel after a reactor accident, then the processing can be performed with existing equipment, but the equipment and metal containers are damaged or degraded by corrosive sea salts
Solution Approach 1:
The patent introduces an electroreducer system with molten salt electrolyte as an intermediary processing medium. The corium is first converted to metal form in the electroreducer, then the resulting metal is processed in an electrorefiner. This intermediary electrochemical processing eliminates direct contact between corrosive sea salts and metal storage containers, preventing the corrosive degradation that would otherwise occur in conventional facilities.
2Temperature
If sea salts are present in the reactor after cooling with seawater, then the reactor can be cooled effectively, but the sea salts deposit and cause corrosive damage to processing equipment and containers
Solution Approach 1:
The patent converts the harmful corrosive effect of sea salts into a beneficial separation process. The electroreducer and electrorefiner systems use molten salt electrolytes that selectively dissolve and separate the sea salt components (alkali and alkaline earth metals) from the corium and fission products. The sea salts are transformed from a harmful corrosive agent into a separable component that can be removed and stabilized as waste, while the desired nuclear materials are recovered in pure form.
3Stability of the object's composition
If electroreduction and electrorefining processes are used to stabilize nuclear material, then purified metal products are produced resistant to leaching, but the process requires complex electrochemical equipment and multiple processing steps
Solution Approach 1:
The patent segments the stabilization process into two distinct functional units: an electroreducer for converting corium to metal form, and an electrorefiner for purifying the metal and separating fission products. Each unit has a specific cathode and anode configuration optimized for its function. This segmentation allows each component to be designed and operated independently, managing the overall system complexity while achieving the goal of producing stable, leaching-resistant nuclear material.
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 stabilizes nuclear materials by converting them into purified metal products and ceramic or metallic waste forms, which are more resistant to leaching, thereby addressing the corrosive effects of sea salts and ensuring the integrity of storage containers, and provides a passive process safety aspect by stopping electrochemical reactions if power is lost.
Implementation Method 1
The nuclear material may be reduced in the first molten salt electrolyte of the electroreducer to produce a reduced material in the reducer cathode assembly
Implementation Method 2
The reduced material may be electrolytically dissolved in the second molten salt electrolyte of the electrorefiner to produce a purified metal product on the refiner cathode assembly
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method 220 for stabilizing a nuclear material may include electrolytically reducing 220d the nuclear material in a first molten salt electrolyte of an electroreducer to produce a reduced material. A reducer waste may accumulate in the first molten salt electrolyte as a byproduct of the electroreduction. After the electroreduction, the reduced material may be electrolytically dissolved 230b in a second molten salt electrolyte of an electrorefiner to produce a purified metal product on a refiner cathode assembly of the electrorefiner. As a result of the electrorefining, a first refiner waste may accumulate in the second molten salt electrolyte and a second refiner waste may accumulate in a refiner anode assembly of the electrorefiner. The reducer waste from the electroreducer and the first refiner waste from the electrorefiner may be converted into a ceramic waste form, while the second refiner waste from the electrorefiner may be converted into a metallic waste form.