Nuclear Fuel Top Nozzle Guide Thimble Joint Structure
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Solution Overview
Problem
The existing joint structure between top nozzles and guide thimbles in nuclear fuel assemblies often experiences issues with the inner-extension tube becoming undesirably rotated or loosened during disassembly due to frictional heat and cold welding effects, making it difficult to separate the components without complicating the assembly and disassembly processes.
Innovation Solution
A joint structure is designed with a rotation-preventing surface on the inner-extension tube and a corresponding rotation-preventing portion on the flow plate, preventing the inner-extension tube from rotating when the inner-extension tube head is removed, thereby maintaining the structural integrity and simplifying the assembly and disassembly processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the inner-extension tube is connected to the guide thimble through a threaded coupling structure, then the structural stability of the nuclear fuel assembly is ensured, but the inner-extension tube may undesirably rotate or become loosened during disassembly due to frictional heat and cold welding effects
Solution Approach 1:
The patent divides the inner-extension tube into two separate components: the inner-extension tube body that remains threaded to the guide thimble, and the inner-extension tube head that is detached during disassembly. This segmentation allows the tube body to maintain structural stability through threading while the head can be easily removed without experiencing rotation or cold welding issues.
Solution Approach 2:
The patent extracts the problematic threaded coupling from the disassembly process by separating the tube head from the tube body. The tube body remains coupled to the guide thimble for stability, while the tube head is removed independently, eliminating the risk of unwanted rotation or cold welding during the disassembly operation.
2Strength
If the contact area between rotating components is increased, then the structural integrity is maintained, but the complexity of the assembly and disassembly processes increases
Solution Approach 1:
The patent segments the inner-extension tube into a tube body and tube head, allowing the tube body to maintain structural integrity through threaded coupling with the guide thimble, while the tube head is detached for simplified removal. This segmentation reduces assembly and disassembly complexity without compromising the structural integrity of the remaining coupled components.
3Ease of operation
If the inner-extension tube head is rotated for separation from the inner-extension tube body, then the disassembly process is simplified, but the inner-extension tube body may undesirably rotate and become loosened from the guide thimble
Solution Approach 1:
The patent segments the inner-extension tube into a tube body that remains coupled to the guide thimble and a tube head that is detached during disassembly. This segmentation enables easy removal of the tube head without rotating the tube body, thereby preventing unwanted rotation and maintaining the stable connection between the tube body and guide thimble.
Solution Approach 2:
The patent extracts the tube head from the tube body, allowing the tube head to be removed without rotating the tube body. This extraction simplifies the disassembly process while preventing the tube body from rotating and becoming loosened from the guide thimble, as the tube body remains stationary and coupled throughout the disassembly operation.
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 solution effectively prevents the inner-extension tube from becoming loosened from the guide thimble during disassembly, reducing the complexity of the assembly and disassembly processes and minimizing the contact area between rotating components, thus facilitating the separation of the top nozzle from the guide thimble.
Implementation Method 1
minimizing the contact area between rotating components, thus facilitating the separation of the top nozzle from the guide thimble
Implementation Method 2
making it difficult to separate the components without complicating the assembly and disassembly processes
Data Source
AI summary
A combination of a top nozzle and a guide thimble of a nuclear fuel assembly and, more particularly, a structure for joining an inner-extension tube, the top nozzle and the guide thimble. When an inner-extension tube head, which is provided as a means for facilitating removal of the top nozzle of the nuclear fuel assembly from the guide thimble, is removed from an inner-extension tube body to separate the top nozzle from the nuclear fuel assembly, the inner-extension tube body is prevented from undesirably rotating, so that the guide thimble and the inner-extension tube body can maintain the joined state.