Circumferential Weld Brushing Tool for Restricted Nuclear Reactor Access
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Solution Overview
Problem
Existing methods fail to effectively access and condition welds in nuclear reactor components, particularly in the restrictive access areas between the shroud outside diameter and vessel inside diameter, to mitigate tensile surface stresses that can lead to crack initiation or growth.
Innovation Solution
A tool assembly with a circumferential plate and a renew brush, driven by a motor and positioning assembly, is designed to access and condition circumferential welds in these restricted areas by rotating and moving the brush circumferentially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional brushing methods are used on welds, then surface conditioning can be applied, but access to welds in restrictive areas between shroud and vessel is impossible
Solution Approach 1:
The tool assembly is designed to nest within the annular space between the shroud and vessel. The circumferential plate fits within this restrictive gap, allowing the brush assembly to access welds in areas that were previously unreachable by conventional external brushing equipment.
Solution Approach 2:
The invention transitions from external access methods to internal access by positioning the brushing tool within the annular dimension between the shroud and vessel. This dimensional approach allows the tool to reach welds on the inner surface of the shroud that cannot be accessed from the outside.
2Ease of operation
If jet pumps are removed to access welds, then surface conditioning becomes possible, but reactor operation is interrupted and complexity increases
Solution Approach 1:
The invention extracts the brushing function from the traditional external equipment and integrates it into a compact tool assembly that operates within the existing reactor structure. This eliminates the need to remove jet pumps or other internal components, as the tool is specifically designed to work within the constrained annular space.
Solution Approach 2:
The tool assembly serves multiple functions: it conditions welds on the shroud, can access different circumferential locations, and operates without requiring reactor disassembly. This multi-functional design replaces the need for complex disassembly procedures while maintaining effective surface conditioning capability.
3Ease of operation
If a compact tool is designed for restrictive access, then welds become accessible, but device complexity increases
Solution Approach 1:
The tool assembly is segmented into distinct functional components: a circumferential plate for structural support and positioning, a brush assembly for surface conditioning, and a drive mechanism for rotation. This segmentation allows each component to be optimized for its specific function while fitting within the constrained annular space.
Solution Approach 2:
The tool incorporates dynamic elements including the rotatable brush assembly that can adapt to the weld surface, and the circumferential plate that can be positioned at different locations within the annular space. This dynamic capability allows the tool to access various weld locations without requiring complex reconfiguration.
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
Enables effective mechanical surface conditioning of welds in previously inaccessible areas, reducing the susceptibility to crack initiation or growth due to tensile surface stresses, thereby enhancing the integrity of nuclear reactor components.
Implementation Method 1
at least one renew brush coupled with the circumferential plate... rotating the renew brush... mechanical surface conditioning of metals
Data Source
AI summary
A tool assembly provides for brushing circumferential welds in a restrictive access area between a cylindrical inner member and a cylindrical outer member such as the shroud and vessel in a nuclear reactor. The tool assembly includes a circumferential plate sized larger than an outside diameter of the inner member and smaller than an inside diameter of the outer member. At least one renew brush is coupled with the circumferential plate, and a motor is coupled with the renew brush that rotates the renew brush. A driving assembly mounted between the inner member and the outer member engages the circumferential plate and circumferentially drives the circumferential plate in the restrictive access area.