Clamp Assembly for Jet Pump Diffuser Weld Repair
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bimetallic welds in jet pump diffuser assemblies of boiling water nuclear reactors are prone to degradation, requiring a reliable method for structural reinforcement or replacement that addresses the challenges of dissimilar metal welding and thermal expansion differences.
Innovation Solution
A clamp assembly with conically shaped pins and tapered holes, and a clamp body made of intermediate thermal expansion material, is used to securely connect the diffuser adapter or lower ring to the tail pipe, minimizing leakage and thermal stresses by matching thermal expansion coefficients and providing a remotely installable solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bimetallic weld is used to join diffuser adapter to tail pipe, then structural connection is achieved, but structural integrity degrades over time due to thermal expansion differences and welding complexity
Solution Approach 1:
A clamp assembly serves as an intermediary component between the diffuser adapter and tail pipe, eliminating the need for direct bimetallic welding. The clamp includes a body with upper and lower clamp portions that engage respectively with the adapter and tail pipe, providing a reliable mechanical connection that avoids the structural integrity issues of dissimilar metal welds.
Solution Approach 2:
The patent replaces the welding process (thermal/chemical joining) with a mechanical fastening system. The clamp assembly uses mechanical engagement features including clamp portions, retaining rings, and fastening mechanisms to connect the diffuser adapter to the tail pipe, substituting the unreliable bimetallic weld with a mechanically robust connection that maintains structural integrity.
2Strength
If traditional welding methods are used for connecting diffuser components, then joint strength is achieved, but installation complexity and maintenance difficulty increase
Solution Approach 1:
The clamp assembly is segmented into distinct components including a clamp body, upper clamp portion, lower clamp portion, retaining rings, and fastening elements. This segmentation allows for modular installation and maintenance, enabling personnel to access, remove, and replace individual components without requiring complex welding procedures or specialized equipment.
Solution Approach 2:
The clamp assembly acts as an intermediary component that simplifies the connection between the diffuser adapter and tail pipe. Instead of requiring direct welding of dissimilar metals, the clamp provides a standardized mechanical interface that is easier to install, inspect, and maintain, thereby improving ease of repair while maintaining joint strength.
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 clamp assembly effectively replaces or repairs the bimetallic weld, ensuring structural integrity and minimizing coolant leakage and thermal stresses, while being simpler to install and maintain than traditional welding methods.
Implementation Method 1
a clamp body made of intermediate thermal expansion material, is used to securely connect the diffuser adapter or lower ring to the tail pipe, minimizing leakage and thermal stresses by matching thermal expansion coefficients
Data Source
AI summary
A clamp assembly connects a diffuser adapter or lower ring to a diffuser tail pipe of a jet pump diffuser in a boiling water nuclear reactor. The clamp assembly includes at least two clamp segments shaped generally corresponding to an exterior circumference of the diffuser, a swivel link affixed at each end of each of the clamp segments, and at least two connecting bands pivotably secured to the swivel links between the ends of the clamp segments. The clamp segments each includes a locking assembly engageable with the diffuser adapter or lower ring and the diffuser tail pipe. The clamp assembly structurally replaces/repairs the weld joining the diffuser adapter or lower ring and the diffuser tail pipe.