Jet Pump Elbow Clamp Repair for Restricted Nuclear Weld Access
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Solution Overview
Problem
Riser pipe elbow welds in nuclear reactors often require repair in restrictive spaces, where conventional welding tooling cannot reach due to insufficient spacing, and the welds are non-standard, making replacement and repair difficult.
Innovation Solution
A system and method using an L-base and drive plate that clamp around the elbow and flow conduits to apply compressive force, relieving tension in the welds without the need for welding, utilizing locking grooves and tongues to secure the components and allowing for machining in situ, enabling repair in limited spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional welding tooling is used to repair welds, then welding can be performed, but the tooling cannot reach the welds due to insufficient spacing in restrictive spaces
Solution Approach 1:
The repair system is divided into separate modular components: a base that attaches to the elbow and a drive plate that attaches to the riser pipe, connected by a rod. This segmentation allows each component to be installed independently in the restrictive space, with the base providing a mounting surface for the rod and drive plate assembly, enabling repair operations without requiring extensive clearance around the elbow.
Solution Approach 2:
The base is designed with legs that extend in multiple directions (e.g., perpendicular to each other) to attach to different surfaces of the elbow, utilizing three-dimensional space efficiently. This allows the repair system to be mounted on the elbow in a compact configuration that fits within the limited spacing, while still providing the necessary attachment points for the rod and drive plate to apply repair forces.
2Ease of repair
If welding is performed in restrictive spaces, then weld repair is possible, but the non-standard nature of welds makes replacement and repair difficult
Solution Approach 1:
The base is designed as a universal mounting component that can be attached to elbows of various configurations and orientations. The drive plate similarly serves multiple functions: it provides attachment to the riser pipe, serves as a mounting surface for the rod, and applies compressive force to the weld. This multi-functionality allows the same basic components to handle different elbow geometries and weld locations without requiring custom tooling for each case.
Solution Approach 2:
The system allows for adjustment of the rod length and positioning to accommodate different elbow sizes, orientations, and weld locations. The base legs can be positioned at various angles and distances from each other to match different elbow geometries. This adjustability enables the repair system to adapt to non-standard weld configurations while maintaining a standardized overall approach to repair.
3Reliability
If a base and drive plate system is used to apply compressive force, then weld tension is relieved, but the device complexity increases
Solution Approach 1:
The base combines multiple functions into a single component: it attaches to the elbow, provides mounting surfaces for the rod, and positions the repair system relative to the weld. The drive plate similarly merges attachment to the riser pipe, rod mounting, and force application functions. This merging reduces the total number of separate components compared to alternative designs that might use multiple brackets, bolts, and positioning elements.
Solution Approach 2:
The repair system extracts the essential function of applying compressive force to the weld and isolates it in the rod and drive plate assembly, separate from the mounting base. This allows the base to be optimized for secure attachment to the elbow while the drive plate assembly is optimized for force application, simplifying each component's design and reducing overall complexity.
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 repair of welds in nuclear reactor jet pumps without the need for conventional welding, maintaining structural integrity and reducing the risk of leakage or damage, even in spaces where standard welding tools cannot access the welds.
Implementation Method 1
The base and drive plate(s) can be driven together to compress and relieve tension in the weld or other joining structure between the two
Implementation Method 2
The base and drive plate(s) may be statically secured with the elbow and joining conduits, such as through locking tongues and grooves
Data Source
AI summary
Systems repair jet pump elbow joining structures like RS1 and RS2 welds. Systems include a base having legs that secure to ends of the elbow in different directions, and a drive plate that joins to flow conduits where they meet the elbow. The drive plate and base may then be pushed together, resulting in compression or joining of the elbow and flow conduit. Multiple drive plates may be used with a single base to compress multiple flow conduits to the base. The base and the drive plates can be driven together with a driving bolt extending through the base and driving plate. To provide a better fit, grooves can be created in the flow conduits through machining from the installed base. The drive plate may be seated into the groove to achieve a desired orientation with less slippage. Example embodiments and methods do not require welding or a welding base.