Multi-Layer Nuclear Fuel Cladding Pipe Swaging Without Interface Gaps
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Solution Overview
Problem
The existing methods for manufacturing nuclear fuel cladding pipes face challenges in ensuring a tight contact between the inner and outer pipes without an interface, which can lead to oxidation and corrosion issues, and require complex processes like using filling materials that are inefficient for mass production and can damage the pipes.
Innovation Solution
A method involving a rod-shaped insertion body made of polymer with elasticity, inserted into the inner pipe to provide a reaction force during the swaging process, allowing the inner and outer pipes to be closely contacted and fixed without an interface, using a series of rollers with decreasing spacing to reduce the pipe diameter while maintaining the pipe's shape and preventing excessive force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner pipe is used to support external pressure without additional support, then the structure is simple, but the inner pipe cannot sufficiently support the pressure applied from outside, preventing close contact between inner and outer pipes
Solution Approach 1:
A rod-shaped insertion body is introduced as an intermediary element inside the inner pipe to support external pressure. This mediator transfers the external pressure load from the inner pipe wall to the insertion body, enabling the inner pipe to maintain its shape and closely contact the outer pipe without requiring the inner pipe itself to have high pressure support capability.
2Manufacturing precision
If filling materials are used to ensure tight contact between pipes, then the contact quality is improved, but the process becomes complex and inefficient for mass production
Solution Approach 1:
The invention extracts and removes the insertion body after it has served its purpose during the swaging process. The insertion body is inserted into the inner pipe before swaging to ensure tight contact, then completely removed afterward, leaving no residual materials inside the pipe. This eliminates the need for filling materials and their associated complex installation and removal processes.
Solution Approach 2:
The insertion body is inserted into the inner pipe in advance before the swaging process. This preliminary action provides the necessary internal support during diameter reduction, ensuring the inner pipe maintains its shape and achieves tight contact with the outer pipe. The insertion body is then removed, having fulfilled its temporary support function.
3Productivity
If excessive force is applied during diameter reduction, then the diameter reduction efficiency is improved, but the pipe may be damaged or deformed
Solution Approach 1:
The rod-shaped insertion body serves as a cushioning element inside the inner pipe during the diameter reduction process. It absorbs and distributes the compressive forces applied during swaging, preventing excessive localized stress that could damage or deform the pipe. The insertion body protects the inner pipe while enabling efficient diameter reduction.
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 enables the efficient manufacturing of multi-layered nuclear fuel cladding pipes with improved mechanical strength, reduced risk of high-temperature oxidation, and stable operation by ensuring a tight contact between the inner and outer pipes without interfaces, and allows for easy removal of the insertion body, enhancing production speed and preventing pipe damage.
Implementation Method 1
The insertion body may have elasticity
Data Source
AI summary
The present inventive concept provides a method for manufacturing a multi-layered nuclear fuel cladding pipe, comprising the steps of: providing a preliminary cladding pipe in which an inner pipe having a rod-shaped insertion body inserted thereinto is disposed in an outer pipe; reducing the diameter of the preliminary cladding pipe by applying pressure from the outside to the inner side of the preliminary cladding pipe; and removing the insertion body from the inner pipe by providing a force in the direction in which the insertion body extends, wherein the inner pipe and the outer pipe may be formed of different metals from each other.