Telescopic Mast Segmentation for Nuclear Fuel Loading Precision
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Solution Overview
Problem
The handling of nuclear fuel assemblies in boiling water reactors poses challenges due to the high deployment stroke of telescopic masts, which affects the verticality and positioning precision of the grappling hook, leading to operational constraints.
Innovation Solution
A loading machine with a telescopic vertical mast featuring a fixed drum, vertically movable barrels with stops and pads for guided deployment and folding, and a slewing ring for orientation, utilizing ultra-high molecular weight polyethylene pads for stiffness and guidance, ensuring precise handling and reduced clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the telescopic mast is deployed to high lengths (around twenty meters), then the handling range of nuclear fuel assemblies is extended, but the verticality of the mast and positioning precision of the grapple deteriorate
Solution Approach 1:
The mast is divided into multiple telescopic barrels that can be deployed and retracted independently. Each barrel is equipped with stops and pads to ensure precise positioning during deployment, allowing the mast to achieve high lengths while maintaining verticality and positioning precision through segmented control.
Solution Approach 2:
Pads made of ultra-high molecular weight polyethylene are introduced as intermediary elements between the barrels. These pads facilitate guided deployment and folding, reducing clearance and ensuring precise positioning of the grapple at extended lengths by mediating the interaction between telescopic segments.
2Length of moving object
If the telescopic mast is deployed to high lengths (around twenty meters), then the handling range of nuclear fuel assemblies is extended, but the verticality of the mast deteriorates
Solution Approach 1:
The mast is divided into multiple telescopic barrels that can be deployed and retracted independently. Each barrel is equipped with stops and pads to ensure precise positioning during deployment, allowing the mast to achieve high lengths while maintaining verticality and positioning precision through segmented control.
Solution Approach 2:
The pads are made of ultra-high molecular weight polyethylene with very high molar mass greater than 10^6, changing the material parameter to provide enhanced stiffness and wear resistance. This material parameter change ensures the mast maintains verticality at extended lengths by providing sufficient structural rigidity.
3Ease of operation
If the barrels are made thin to reduce weight and increase deployability, then the mast becomes more manageable, but the stiffness against horizontal forces deteriorates
Solution Approach 1:
The pads are made of ultra-high molecular weight polyethylene, a composite material that provides both sufficient stiffness to resist horizontal forces and the necessary thinness for deployability. This material choice allows the barrels to be made thin while maintaining the required structural rigidity through the pads' mechanical properties.
Solution Approach 2:
The pads are made of ultra-high molecular weight polyethylene with very high molar mass greater than 10^6, changing the material parameter to provide enhanced stiffness and wear resistance. This material parameter change ensures the mast maintains verticality at extended lengths by providing sufficient structural rigidity.
4Productivity
If the mast is used in high radiation environments, then nuclear fuel handling is performed, but the wear and radiation susceptibility increase
Solution Approach 1:
The pads are made of ultra-high molecular weight polyethylene, a composite material that provides both sufficient stiffness to resist horizontal forces and the necessary thinness for deployability. This material choice allows the barrels to be made thin while maintaining the required structural rigidity through the pads' mechanical properties.
Solution Approach 2:
The pads are designed as replaceable components that can be easily replaced when worn or damaged by radiation. This approach allows the mast to operate continuously in high radiation environments, with worn pads replaced rather than the entire mast, maintaining productivity while managing reliability through component replacement.
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 enhances the precision and modularity of nuclear fuel assembly handling, maintaining verticality and positioning accuracy even at extended lengths, and extends the maintenance interval by reducing wear and radiation susceptibility.
Implementation Method 1
pads, capable of facilitating the guidance of the deployment and folding of the drums within each other
Implementation Method 2
The material constituting the pads is made of ultra-high molecular weight polyethylene, typically with a very high molar mass greater than 10^6
Data Source
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AI summary
This machine for loading nuclear fuel assemblies (3) into a reactor vessel (1) of a nuclear reactor comprises a horizontally mobile trolley (5) to which is attached a telescopic vertical mast (4) comprising a fixed drum (7) attached to the trolley and several vertically mobile drums (8-11) mounted coaxially with the fixed drum, so as to be able to extend telescopically. The innermost drum (11) is equipped with a grapple (12) capable of connecting to the upper end of a fuel assembly. The drums have a square cross-section. The drums are fitted with stops that cooperate with each other to allow for individual deployment of the drums and their retraction by raising the innermost drum.Each drum, with the exception of the innermost drum, is equipped at the level of the four lateral walls that define it, with pads designed to facilitate the guidance of the deployment and refolding of the drums within each other.