Mechanical Modification of Spent Nuclear Fuel for Deep Geological Disposal
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Solution Overview
Problem
Current methods for disposing of spent nuclear fuel (SNF) are costly, time-consuming, and pose risks of nuclear material proliferation, as they involve reprocessing that separates plutonium, leading to increased waste volume and complexity, whereas direct disposal in deep geological repositories faces challenges like near-wellbore damage and fluid migration.
Innovation Solution
Mechanical modification of SNF assemblies through size reduction, compression, and shaping into dense waste pucks for secure encapsulation within cylindrical capsules, followed by deep geological disposal in horizontal wellbores, minimizing chemical treatment and avoiding reprocessing, with criticality analysis to ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SNF assemblies are reprocessed to separate plutonium, then nuclear material can be recovered for reuse, but waste volume increases and complexity increases
Solution Approach 1:
The patent extracts and removes the fuel rods containing nuclear material from the spent fuel assemblies, separating them from the metal cladding and structural components. This extraction approach allows the fuel rods to be disposed of as waste while the metal components can be recycled, thereby reducing overall waste volume without requiring complex chemical reprocessing procedures
2Reliability
If SNF is disposed of in vertical wellbores, then disposal can be implemented, but near-wellbore damage and fluid migration risks occur
Solution Approach 1:
The patent changes the disposal geometry from vertical to horizontal wellbores, and further modifies the waste form from intact assemblies to compacted pellets. These parameter changes in disposal configuration and waste physical state reduce the impact of near-wellbore damage and minimize fluid migration pathways, thereby improving disposal safety
3Productivity
If SNF assemblies are mechanically modified through size reduction and compression, then disposal efficiency improves, but processing time and energy increase
Solution Approach 1:
The patent segments the spent fuel assemblies by removing individual fuel rods from their cladding, then further segments these rods into smaller pellets. This segmentation enables more efficient packing and compaction, improving disposal efficiency while the modular nature of the process allows for optimized processing rates to minimize time loss
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 safe, cost-effective, and timely disposal of large volumes of SNF, reducing the risk of nuclear material misuse and environmental contamination by securely sealing waste in deep geological formations, while avoiding the complexities and costs associated with reprocessing.
Implementation Method 1
Mechanical modification of SNF assemblies through size reduction, compression, and shaping into dense waste pucks
Data Source
AI summary
Devices, systems, and methods for mechanical and/or physical modifications of nuclear waste forms, such as, but not limited to, spent nuclear fuel (SNF) assemblies, for disposing within deeply located geologic repositories, where such methods may include: (1) reducing a size of the original nuclear waste form(s) by feeding the original nuclear waste form(s) into specialty industrial machines, such as, but not limited to, industrial chipping machines (or the like), for size reduction to yield waste chips; (2) compressing, compacting, extruding, and/or shaping the waste chips into waste pucks by using industrial compactor machines; (3) loading the generated dense waste pucks into waste capsules; and (4) landing the waste capsules, filled with the dense waste pucks, into sections of wellbores that are located within deep geological formations.