Underwater Vehicle Guide Roller Vertical Positioning
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Solution Overview
Problem
Existing underwater inspection and repair systems for nuclear reactor core internals face challenges in maintaining vertical positioning due to dislocation caused by weight and cable forces, making it difficult to accurately move the work tool along the intended path.
Innovation Solution
An underwater vehicle system equipped with drive wheels, a contact force generating unit, an ascending force control unit, and guide rollers that engage with the undersurface of the structure, allowing precise horizontal movement and preventing vertical displacement, along with an optional work tool carrier connected via a cable for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main body is suspended in water in vertical posture using a float, then the system can be positioned in water, but the vertical position may dislocate due to weight and cable forces
Solution Approach 1:
The patent applies the anti-weight principle by introducing a guide roller that engages with the undersurface of the reactor pressure vessel. The guide roller is pressed against the undersurface by the weight of the main body, creating a counterbalancing mechanism that prevents vertical dislocation. This allows the system to maintain stable vertical positioning while being suspended in water, resolving the contradiction between reliability of positioning and ease of operation control.
2Ease of operation
If the drive wheels are used to move along the vertical wall, then the work tool can reach the target location, but vertical dislocation occurs perpendicular to the running direction
Solution Approach 1:
The guide roller acts as an intermediary element between the main body and the reactor pressure vessel. By engaging with the undersurface of the vessel and being pressed against it by the main body's weight, the guide roller serves as a mediator that constrains vertical movement while allowing horizontal movement along the vertical surface. This resolves the contradiction by enabling movement along the vertical wall while preventing perpendicular dislocation.
3Force
If the main body weight is used to press against the vertical wall, then contact force is generated for movement, but vertical position cannot be corrected to target position
Solution Approach 1:
The guide roller implements the anti-weight principle by using the main body's weight to press against the undersurface of the reactor pressure vessel. This creates a counterbalancing force that prevents vertical dislocation while maintaining the necessary contact force for horizontal movement. The weight that previously caused positioning errors is now utilized beneficially to maintain stable contact and prevent vertical drift.
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
The system effectively maintains accurate vertical positioning and stable horizontal movement of the work tool along the reactor structure, ensuring precise inspection and repair operations by controlling ascending forces and using guide rollers to counteract buoyancy-induced displacement.
Implementation Method 1
an ascending force control unit adapted to control an ascending force acting on the underwater vehicle; and a guide roller, adapted to engage with an undersurface of the underwater structure, that is pressed against the undersurface of the underwater structure by an ascending force acting on the underwater vehicle
Data Source
AI summary
Disclosed is a system that performs inspection and repair of an underwater structure, specifically core internals in a pressure vessel. An underwater vehicle is provided with a drive wheel, a contact force generating unit (e.g., thruster) that presses the drive wheel to a vertical wall of the underwater structure, an ascending force control unit (e.g., ballast) that controls the buoyancy of the vehicle, a guide roller that engages with and is pressed against an undersurface of the underwater structure by the ascending force controlled by the ascending force control unit. The underwater vehicle is appropriately positioned with respect to the vertical direction by the guide roller. The drive wheel is driven for rotation so that the underwater vehicle runs horizontally along the vertical wall to reach the inspection or repair site, where the inspection or repair is carried out by work tool mounted to the underwater vehicle.