Permissive Control System for Reactor Fuel Grapple Orientation
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Solution Overview
Problem
In nuclear reactors, the manual orientation and placement of fuel assemblies and blade guides are prone to errors, leading to costly downtime, potential accidents, and regulatory issues due to the reliance on human operators for correct positioning and orientation during refueling and startup processes.
Innovation Solution
A Permissive Control System that uses a telescoping mast with a grapple and proximity switches to monitor and ensure correct orientation and location of reactor components, providing error messages if misalignment occurs, and allowing for semi-automatic or automatic control of component movement through a PLC and industrial computer interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual orientation and placement of fuel assemblies and blade guides is performed by human operators, then operational flexibility is maintained, but error rate increases leading to costly downtime and potential accidents
Solution Approach 1:
The patent replaces manual mechanical operations with an automated control system that uses sensors, processors, and actuators to position and orient reactor components. The system automatically calculates orientation angles, determines target positions, and controls the mast and grapple mechanisms to achieve precise component placement, eliminating human error while maintaining operational capability.
Solution Approach 2:
The control system performs self-verification by automatically comparing the actual position and orientation of reactor components against the planned configuration. The system independently detects errors, generates error messages, and can automatically correct misorientations without requiring human intervention, making the system self-sufficient in ensuring correct component placement.
2Manufacturing precision
If automated control system with sensors and processors is implemented, then accuracy of component positioning is improved, but system complexity increases
Solution Approach 1:
The control system is designed to perform multiple functions using a unified architecture: it tracks the mast and grapple positions, calculates orientation angles, determines target component locations, controls motorized actuators, and verifies final positioning. This multi-functional integration reduces the need for separate specialized systems while achieving high precision in component placement.
Solution Approach 2:
The patent introduces a programmable processor as an intermediary between the physical components (mast, grapple, sensors) and the control objectives. This processor acts as a mediator that receives sensor data, executes positioning algorithms, and generates control signals, simplifying the overall system architecture by centralizing the intelligence required for precise positioning.
3Reliability
If permissive control system with error detection is used, then safety and error prevention are enhanced, but response time and operational speed may be reduced
Solution Approach 1:
The control system performs preliminary calculations of the required orientation angles and target positions before actual component movement begins. By pre-computing the positioning parameters based on the current mast and grapple locations, the system eliminates the need for time-consuming measurements and adjustments during the refueling operation, thus maintaining high speed while ensuring accuracy.
Solution Approach 2:
The system continuously monitors the actual position and orientation of the mast and grapple using sensors and compares this feedback against the planned trajectory. This real-time feedback allows the system to make immediate corrections, preventing errors from developing and ensuring that components are placed correctly on the first attempt, thereby maintaining operational speed while enhancing safety.
Data Source
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AI summary
A method and apparatus for the permissive control of a mast and fuel grapple to be used in the movement of reactor fuel components, including fuel assemblies, single blade and double blade guides, to be used in a Boiling Water Reactor (BWR) nuclear reactor. The Permissive Control System reduces the chance of human error associated with the movement of reactor components by assisting in controlling the location (plant coordinate) of the mast for picking-up and dropping-off reactor components, the sequence of reactor component movements, the orientation (angular rotation) of the mast and fuel grapple, the raising and lowering of the grapple, and the opening and closing of the fuel grapple.