Modular Tubesheet Walker for Nuclear Steam Generator Inspection
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Solution Overview
Problem
Current robotic systems for servicing heat exchanger tubes in nuclear steam generators are large, complex, and expensive, requiring extensive time and personnel exposure for maintenance, and are not suitable for efficient inspection and repair due to their size and complexity.
Innovation Solution
A lightweight, easy-to-maintain robotic tubesheet walker with two rails connected by a central hinge, equipped with carriages and gripper mechanisms that allow for quick movement and tool deployment along the tubesheet, enabling efficient inspection and maintenance by anchoring and repositioning on the tubesheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sophisticated robotic manipulators are used for steam generator servicing, then repair capability is improved, but device complexity and cost increase
Solution Approach 1:
The robotic system is divided into separate functional modules: a mobile platform for traversal, a tool carrier for holding inspection and repair tools, and interchangeable tool assemblies. This segmentation allows each module to be optimized independently and simplifies the overall system complexity while maintaining comprehensive repair capabilities.
Solution Approach 2:
The tool carrier is designed with universal mounting capabilities to accommodate multiple different tool assemblies for various inspection and repair tasks. The mobile platform provides universal mobility across the tubesheet, and the system can perform multiple functions including eddy current inspection, visual inspection, and tube plugging using different tools on the same platform.
2Adaptability or versatility
If large robotic systems are deployed, then service capability is improved, but transportation and setup time increase
Solution Approach 1:
The system is segmented into compact, modular components that can be easily transported and quickly assembled. The mobile platform and tool carrier are designed as separate units that can be moved independently and assembled at the work site, significantly reducing transportation time and setup complexity compared to large monolithic robotic systems.
Solution Approach 2:
The mobile platform incorporates dynamic movement capabilities with drive mechanisms that allow it to autonomously navigate to different work locations on the tubesheet. This dynamic positioning capability eliminates the need for time-consuming manual setup and repositioning of large fixed robotic systems.
3Productivity
If multiple robotic units are installed on steam generator sections, then inspection coverage is improved, but device size and installation difficulty increase
Solution Approach 1:
The system is designed as a modular platform that can be replicated and installed in multiple locations on the steam generator. Each mobile platform unit is a self-contained module that can be independently installed and operated, allowing parallel inspection of multiple tube sections simultaneously without requiring complex integration between units.
Solution Approach 2:
The mobile platform is designed with adjustable and configurable parameters including tool carrier positioning, gripper arm lengths, and tool mounting configurations. These parameter adjustments allow the same basic platform design to be adapted to different steam generator configurations and inspection requirements without requiring custom-designed robotic units for each application.
4Measurement precision
If current maintenance robots are used, then inspection capability is improved, but maintenance time and radiation exposure increase
Solution Approach 1:
The system is pre-configured with multiple inspection tools including eddy current probes and visual inspection cameras that can be quickly deployed. The mobile platform is pre-positioned on the tubesheet and can rapidly move to different inspection locations, eliminating the need for time-consuming setup procedures and reducing the time personnel are exposed to radiation during maintenance operations.
Solution Approach 2:
The system replaces complex mechanical positioning and tool-changing mechanisms with more streamlined approaches including pre-mounted tools, simplified drive mechanisms, and automated positioning systems that reduce maintenance requirements and minimize the time needed for system maintenance and recalibration.
Data Source
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AI summary
A robotic tubesheet walker having two rails connected by a central hinge, wherein the central hinge can be opened or closed by an actuation device. Upon each rail is mounted a carriage, wherein each carriage can move along its respective rail toward or away from the central hinge by means of a drive mechanism. Each carriage further contains at least two "gripper" attachment mechanisms, such as camlocks, to grip the tubesheet. The grippers either insert into tube holes within the tubesheet to fasten the respective carriage to the tubesheet, or retract to disengage. Further attached to the central hinge is a tool support fixture, and attached to the tool support fixture is a coupler that holds maintenance or inspection tools.