Crossed-Field Plasma Separation of High-Level Nuclear Waste
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Solution Overview
Problem
The increasing volume of high-level nuclear waste from nuclear power plants poses challenges in storage and disposal due to its radioactive composition, with a need for a method to separate high-mass, more radioactive portions from low-mass, less radioactive portions to reduce storage volume effectively.
Innovation Solution
A separation apparatus utilizing inductively-coupled plasma torches and magnetic and electric fields to separate high-level nuclear waste into high-mass and low-mass portions by injecting a multi-species stream into a cylindrical separation chamber, where the crossed fields direct high-mass portions radially outward and low-mass portions along the chamber axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-level nuclear waste is stored in its original form, then the storage volume is large, but the radioactivity distribution is uneven with low-mass elements contributing most to radioactivity
Solution Approach 1:
The nuclear waste is segmented into different mass portions using electromagnetic separation. The waste stream is divided into low-mass radioactive elements (e.g., fission products with mass < 130 amu) and high-mass elements (e.g., actinides with mass > 130 amu), allowing concentrated storage of the highly radioactive low-mass portion and reduced-volume storage of the less radioactive high-mass portion.
Solution Approach 2:
The invention changes the physical state of the waste by ionizing it through plasma generation. The waste is converted from neutral atoms to ionized particles, enabling manipulation and separation through electromagnetic fields. This parameter change allows for effective separation based on mass-to-charge ratio.
2Ease of manufacture
If conventional storage methods are used for high-level nuclear waste, then the disposal cost increases, but the waste composition remains unchanged with disproportionate radioactivity
Solution Approach 1:
The highly radioactive low-mass elements are extracted from the bulk waste material through electromagnetic separation. By removing and concentrating the most radioactive components (fission products like I-131, Cs-137, Sr-90 with masses 131-137 amu), the remaining high-mass portion requires less stringent and therefore less expensive disposal measures.
3Productivity
If the waste is separated into high-mass and low-mass portions, then the storage efficiency improves, but the device complexity increases with plasma torches and electromagnetic fields
Solution Approach 1:
The electromagnetic separation apparatus serves multiple functions: it ionizes the waste, separates it by mass, and concentrates the radioactive portions in a single integrated system. The plasma torch and electromagnetic fields perform both the ionization and separation tasks that would otherwise require multiple separate processing steps.
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 apparatus efficiently separates high-mass and low-mass portions of nuclear waste, reducing storage volume and enhancing the safety of radioactive waste management by effectively segregating more and less radioactive materials.
Implementation Method 1
first inductively-coupled plasma torch assembly being mounted to the inlet end of the housing... first rf coil which is disposed along the injection channel, and which is connected to at least one external power source for energizing the plasma-forming gas within the injection channel to form a plasma discharge
Implementation Method 2
the plasma torch being formed to inject a multi-species stream into the separation chamber via the through-opening of the inlet end, the multi-species stream including a partially ionized supply of the high-level nuclear waste and a plasma discharge
Implementation Method 3
first and second magnetic elements circumferentially disposed around the first axial housing section and the third axial housing section, respectively, the first and second magnetic elements being positioned for generating a magnetic field that is substantially parallel to a longitudinal axis of the cylindrical separation chamber
Implementation Method 4
the plurality of concentric electrodes being connected to at least one external power source such that each of the plurality of concentric electrodes receives a unique electric potential from the at least one external power source for generating an electric field that is perpendicular to the magnetic field
Implementation Method 5
the magnetic and electric fields being oriented along the separation chamber such that when the multi-species stream is injected into the separation chamber, the high-mass portion of the fluidized supply of high-level nuclear waste is ejected radially outwards towards the at least one first outlet aperture, and the low-mass portion of the fluidized supply high-level nuclear waste is directed along the longitudinal axis of the separation chamber
Data Source
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AI summary
A separation apparatus (100) for separating a supply of high-level nuclear waste (HLW), where the HL nuclear waste is separated into high-mass and low-mass portions. The high-and-low mass portions of the HLW have respective atomic masses that are above and below an atomic mass cut-off point of the separation apparatus. The separation apparatus includes first (120) and second (130) ICP torches that are respectively mounted to and within an apparatus housing (110). The apparatus housing defines a cylindrical separation chamber and includes first (140a) and second (140b) magnetic elements which generate a magnetic field along the length of the separation chamber, and a plurality concentric ring electrodes (250) which generate an electric field that is perpendicular to, and which crosses the magnetic field. The supply of HLW is subject to a mass separation process within the separation chamber using the set of crossed electric and magnetic fields.