Remote Bolt Tensioning Carts for Nuclear Vessel Assembly
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Solution Overview
Problem
Current stud tensioning mechanisms in nuclear and sub-sea industries require pre-installation of fasteners and manual tooling, which is not feasible in high-radiation, remote operating environments due to the size and radiological hazards, limiting the ability to correct malfunctioning machines without manned intervention.
Innovation Solution
A remotely or autonomously operated bolt installation and removal system with a multi-rotating axis control scheme and modular tool carts that surround the nuclear vessel, allowing for the installation, tensioning, de-tensioning, and removal of closure bolts on nuclear reactor pressure vessels, enabling automated operations in high-radiation environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual tooling and pre-installation of fasteners are used, then the tensioning mechanism can be simple and reliable, but the system requires manned intervention which is not feasible in high-radiation environments
Solution Approach 1:
The system uses self-aligning fixtures and automated positioning mechanisms that allow the robotic arm to automatically locate and engage bolts without manual intervention. The fixture includes定位 features that guide the bolt installation process, enabling the system to service itself in terms of positioning and alignment.
Solution Approach 2:
Manual mechanical operations are replaced with a robotic arm equipped with specialized end effectors. The robotic system uses controlled mechanical movements, hydraulic actuation, and electronic control to perform bolt installation, tensioning, and removal operations that previously required human operators with manual tools.
2Object-affected harmful factors
If remote or autonomous operation is implemented, then safety in high-radiation environments is improved, but the control systems become more complex
Solution Approach 1:
The robotic arm is designed with multi-functional end effectors that can perform multiple operations (bolt installation, tensioning, removal) with a single device. The system integrates hydraulic actuation, electronic control, and mechanical positioning into one unified platform, reducing the need for multiple separate systems.
Solution Approach 2:
The system introduces an intermediary robotic system that acts as a mediator between the operator and the high-radiation environment. The robotic arm translates operator commands into precise mechanical actions while isolating human operators from radiation exposure, with sensors and actuators serving as intermediaries for force and position control.
3Productivity
If automated bolt installation and tensioning is achieved, then productivity and efficiency are improved, but the precision of fastener installation becomes more difficult to control
Solution Approach 1:
The system incorporates sensors that provide feedback on bolt position, tension force, and alignment status. This feedback is used by the control system to adjust robotic arm movements and actuator forces in real-time, ensuring precise bolt installation and tensioning while maintaining high productivity through automated operation.
Solution Approach 2:
The fixture and robotic system perform preliminary positioning and alignment actions before final bolt installation. The system pre-positions bolts, pre-aligns flanges, and pre-tensions fasteners in controlled stages, ensuring precision is established before final assembly operations to maintain both speed and accuracy.
Data Source
AI summary
A bolt installation and removal (BIR) system is used for assembling and disassembling a nuclear vessel. The BIR system includes a platform with a stand for supporting the nuclear vessel. A track extends around an outside perimeter of the platform and multiple tool carts include wheels that roll on the track. Tool towers are located on the carts and include tool assemblies configured to install and remove bolts on the nuclear reactor vessel. Magazine towers also extend up from the tool carts next to the tool towers and include magazines that hold bolts for exchanging with the tool assemblies. Drive mechanisms move tool heads in the tool assemblies around a first vertical axis, vertically up and down, and laterally to more simply and reliably install and remove the bolts in a radioactive underwater environment.