Fuel Assembly Loading Machine Movable Stop Centering
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Solution Overview
Problem
Conventional fuel assembly loading machines are limited in their ability to quickly and flexibly respond to centering issues during fuel element handling and transportation, leading to increased time and risk of damage during refueling processes in pressurized water reactors.
Innovation Solution
A movable stop mechanism attached to the guide mast, actuated by a separate lifting mechanism, allows the centering bell to be moved from its end position to an intermediate position, enabling flexible centering and lateral movement of the fuel element loading machine independently of the main hoist, reducing contact with neighboring fuel bundles and enhancing operational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the centering bell is fully raised to the upper end of the guide mast to prevent fuel assembly damage, then safety is improved, but the time required for fuel element changeover increases and operational flexibility is reduced
Solution Approach 1:
The lifting mechanism is segmented into two independent parts: the main lifting mechanism for overall vertical movement and a separate special lifting mechanism for the movable stop. This segmentation allows the centering bell to be partially raised independently without requiring full raising of all telescopic elements, thus reducing changeover time while maintaining safety.
Solution Approach 2:
The stop is made movable rather than fixed, allowing dynamic adjustment of the centering bell's position. The movable stop can be raised or lowered independently to provide the necessary lifting for centering operations, enabling flexible and rapid response to centering problems without compromising safety.
2Device complexity
If the centering bell is raised using only the main lifting mechanism, then structural simplicity is maintained, but operational flexibility and speed of response to centering problems are reduced
Solution Approach 1:
The lifting function is divided between the main lifting mechanism and a separate special lifting mechanism for the movable stop. This segmentation provides operational flexibility for centering operations while keeping each individual mechanism relatively simple in structure.
Solution Approach 2:
The movable stop acts as an intermediary element between the special lifting mechanism and the centering bell. It transfers the lifting force selectively to the centering bell when needed, enabling flexible centering operations without requiring complex integration of lifting functions.
3Adaptability or versatility
If the centering bell is raised independently of the main hoist, then lateral movement and flexible centering are enabled, but device complexity increases due to the separate lifting mechanism
Solution Approach 1:
The lifting system is segmented into independent components: the main lifting mechanism for overall movement and a separate special lifting mechanism for the movable stop. This allows independent control of the centering bell's position, enabling lateral movement and flexible centering operations.
Solution Approach 2:
The separate lifting mechanism for the movable stop provides self-contained functionality for centering operations. It can operate independently of the main hoist to raise or lower the centering bell as needed, providing versatile lateral movement capability without requiring complex integration with the main lifting system.
Data Source
Figure 1
Figure 2
AI summary
A fuel assembly loading machine (2) comprises a guide mast (10) and telescopic elements which can be telescopically lowered out of the guide mast (10) and raised again and are in the form of a centering bell (12), a fuel assembly gripper (14) and a control assembly gripper (16), wherein the telescopic elements are coupled to one another, and are operatively connected to a common main lifting mechanism (18), in such a way that, when the telescopic elements are raised out of the lowered position, initially the control assembly gripper (16) carries along the fuel assembly gripper (14), and then the fuel assembly gripper (14) carries along the centering bell (12), and wherein the guide mast (10) has a fixed stop (22), which fixes the end position of the centering bell (12) which can be reached during lowering. Such a fuel assembly loading machine (2) is intended to be developed such that the amount of time required for the fuel assembly change is reduced in comparison with the conventional technology, and such that a quicker and more effective response to any centering problems which may occur is possible than has hitherto been the case. According to the invention, a stop (40) is fitted on the guide mast (10) for this purpose, said stop being capable of being moved by means of a separate special lifting mechanism (42) in the lifting or lowering direction (38) and interacting with an associated supporting flange (20) of the centering bell (12), with the result that the centering bell (12) can be raised out of the end position of said centering bell into an intermediate position lying above this by the movable stop (40) being raised.