Jet Pump Measuring Pipe Repair Using C-Clamp and Induction Heating
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Solution Overview
Problem
The existing methods for repairing measuring pipes in jet pumps within boiling water reactors face challenges due to the pipes' horizontal installation in narrow spaces and high-radiation environments, making conventional repair techniques difficult and time-consuming, especially when ruptures occur at welding parts or in hard-to-reach areas.
Innovation Solution
A method and device involving a C-shaped clamp and a measuring pipe connecting unit with a spool piece and induction heating, allowing for remote-controlled repair of ruptured measuring pipes by fixing a support member, connecting pipes using a measuring pipe connector, and heating the connecting pipes to facilitate connection and repair within the reactor pressure vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If conventional repair methods are used for horizontally installed measuring pipes in narrow spaces, then repair can be performed, but the repair work becomes extremely difficult and time-consuming due to limited access and complex positioning requirements
Solution Approach 1:
The repair device is divided into multiple functional modules: a C-shaped clamp for support, a positioning device for alignment, and a welding device for repair. This segmentation allows each module to be independently operated and positioned, making the overall repair process feasible in narrow spaces where a single integrated device would be too complex to maneuver.
Solution Approach 2:
The C-shaped clamp serves as an intermediary support structure that attaches to the reactor vessel wall and provides a stable base for the positioning and welding operations. This intermediary device bridges the gap between the limited access environment and the repair operations required, enabling workers to perform repairs without direct access to the measuring pipe location.
2Reliability
If remote-controlled underwater repair is performed, then repair work can be conducted in high-radiation areas, but the complexity of the repair device increases due to the need for remote operation capabilities
Solution Approach 1:
The repair system is segmented into a simple mechanical support structure (C-shaped clamp) that can be remotely positioned and secured, separate from the welding operation. This segmentation allows the support structure to be installed remotely while maintaining relatively simple design, avoiding the need for complex integrated remote manipulation systems.
3Productivity
If the measuring pipe is horizontally installed in a narrow annular space, then the jet pump can function properly, but repair access becomes severely limited with intervals less than 150 mm between the pipe and shroud
Solution Approach 1:
The C-shaped clamp utilizes the radial dimension by attaching to the outer surface of the reactor vessel wall, perpendicular to the horizontal measuring pipe. This dimensional approach allows the repair device to access the pipe from the radial direction rather than requiring linear access along the narrow annular space, effectively bypassing the 150 mm spacing constraint.
Solution Approach 2:
The C-shaped clamp acts as an intermediary structure that transfers the repair operation from the constrained narrow annular space to the more accessible outer surface of the reactor vessel. By anchoring to the vessel wall and extending inward, it creates a new access pathway that is not limited by the original horizontal spacing constraints.
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 enables efficient and safe repair of horizontally installed measuring pipes in narrow spaces, reducing repair time and improving workability by using a C-shaped clamp and induction heating, thus addressing the challenges of conventional repair methods.
Implementation Method 1
heating the connecting pipes to facilitate connection and repair within the reactor pressure vessel
Data Source
AI summary
A jet pump measuring pipe repair method that repairs a ruptured part of a measuring pipe horizontally installed to a lower portion of a jet pump provided in reactor water inside a reactor pressure vessel. The repair method includes: fixing a support member to the jet pump near the measuring pipe left remained; mounting, after the support member fixing, a measuring pipe connector provided with a pipe-repairing pipe having both ends over which connecting pipes are fitted, respectively, to the support member; connecting, after the connector mounting, the remaining measuring pipe and connecting pipe using the measuring pipe connector.