Control Rod Handling Apparatus Alignment and Connection
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Solution Overview
Problem
The existing method for connecting control rods to control rod drive mechanisms in BWRs is inefficient due to misalignment issues between coupling sockets and spuds, leading to prolonged exchange times and potential disruptions during periodic inspections.
Innovation Solution
A control rod handling apparatus that positions the coupling socket at the upper end of the hollow piston and rotates it to align with the coupling spud, allowing the control rod to descend by its own weight and insert the projections into the socket, thereby simplifying and accelerating the connection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control rod handling apparatus moves down to connect the coupling socket and coupling spud, then the connection operation can be performed, but misalignment between the coupling components occurs causing the descent to stop
Solution Approach 1:
The control rod is preliminarily rotated to a predetermined angle before the coupling socket and coupling spud are connected. This preliminary rotation ensures that the coupling components are pre-aligned in the correct phase relationship, preventing misalignment during the descent operation and allowing the connection to proceed smoothly without stopping.
2Productivity
If the control rod handling apparatus moves down to insert coupling spud into coupling socket, then connection is achieved, but the operation time is prolonged due to repeated alignment adjustments
Solution Approach 1:
The control rod is rotated to a predetermined angle before insertion, pre-aligning the coupling components. This eliminates the need for repeated descent-stop-rotate cycles during the connection operation, significantly reducing the time required for control rod exchange and improving overall productivity.
Solution Approach 2:
The control rod's own weight is utilized to facilitate the insertion of the coupling spud into the coupling socket. Once the components are pre-aligned through preliminary rotation, the control rod descends under its own weight without requiring additional driving force or repeated operational cycles, thereby reducing exchange time.
3Ease of operation
If the coupling socket and coupling spud are connected without proper phase alignment, then the connection operation can proceed, but mechanical misalignment occurs causing operational delays
Solution Approach 1:
The control rod is preliminarily rotated to a predetermined angle before the coupling operation. This preliminary action ensures that the coupling socket and coupling spud are in the correct phase relationship, achieving precise alignment without requiring complex real-time adjustments during the connection procedure.
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 approach significantly reduces the time required for connecting control rods to the drive mechanism, ensuring reliable and efficient operations by ensuring proper alignment and using the weight of the control rod to facilitate insertion, thus minimizing the risk of mechanical misalignment and operational delays.
Implementation Method 1
allowing the control rod to descend by its own weight and insert the projections into the socket
Data Source
AI summary
A control rod grasped by a hook of a grasping equipment is moved down and is positioned at an upper end of a hollow piston of a control rod drive mechanism (CRD) in a state that the control rod is fully withdrawn from a core. Furthermore, the hook is inserted into an opening of a handle of the control rod. The hook is lifted up so as to make contact with the handle. The control rod grasped by the grasping equipment is rotated by a grasping equipment rotation apparatus. A state that gaps formed between joint convexities in a coupling socket of the control rod are positioned right above coupling spud convexities of the hollow piston occurs. At this time, the control rod falls by its own weight and the coupling spud convexities pass through the gaps. A grasping equipment movement apparatus suppresses the falling speed of the control rod. The control rod is rotated at 90° and the control rod and CRD are connected. The time required for connecting the control rod and the hollow piston of the control rod drive mechanism can be shortened even further.