Nuclear Control Rod Transfer Device Alignment
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Solution Overview
Problem
Existing transfer devices for control rod assemblies in nuclear power plants face challenges in reliability and ease of operation due to the extended length of the transfer mechanism, which is difficult to align and reinsert poison rods accurately without additional alignment means.
Innovation Solution
A transfer device utilizing an overhead crane with a telescoping inner member, a gripper assembly, and an interlock assembly that aligns control rods with guide thimble tubes, featuring alignment cards and a gripper assembly with laterally extending fins to prevent rotation and ensure precise alignment and support during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a telescoping inner member with gripper assembly is used within the upper latch tube assembly, then the transfer device can be suspended from the overhead crane and moved between fuel assemblies, but the extended length of the transfer mechanism makes it awkward to maneuver and difficult to align precisely
Solution Approach 1:
The patent applies nesting by placing the telescoping inner member with gripper assembly inside the upper latch tube assembly. This nested configuration allows the transfer device to be suspended from the overhead crane while maintaining a compact form that is easier to maneuver and align between fuel assemblies.
2Reliability
If comb assemblies are used as alignment means, then poison rods can be supported and guided during transfer, but the device complexity increases with multiple plates, slots, and grids
Solution Approach 1:
The patent extracts the alignment function from the complex comb assembly structure and integrates it directly into the enclosure assembly through alignment cards. This simplifies the device by eliminating the need for separate comb assemblies with multiple plates, slots, and grids while maintaining the necessary alignment and support functions.
3Measurement precision
If the inner member is slidably supported within the upper latch tube assembly to telescope coaxially, then the control rod assembly can be precisely aligned with guide thimble tubes, but the device requires additional interlock assembly to couple at specific elevations
Solution Approach 1:
The patent uses the interlock assembly as an intermediary mechanism that couples the inner member to the upper latch tube assembly at specific elevations. This intermediary structure enables precise alignment between the control rod assembly and guide thimble tubes while maintaining a manageable device complexity through standardized coupling interfaces.
Data Source
Figure 1
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Figure 3~3A
AI summary
A telescoping rod control cluster assembly change tool for moving control rod assemblies among fuel assemblies in a nuclear facility. The operation of the tool is completely mechanical and the telescoping feature enables the tool to have a relatively low profile when it is being moved and stored without housing a control rod assembly. Rigidly supported alignment cards guide a gripper that attaches to the control rod assembly as the control rod assembly is withdrawn into the tool with the alignment cards preventing any lateral or rotational movement of the gripper.