Ball Joint Clamp for Nuclear Jet Pump Sensing Line Vibration
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Solution Overview
Problem
Conventional jet pump sensing lines in nuclear reactors are prone to premature damage due to flow-induced vibration and radiation degradation, leading to unseating and damage, especially as power plants are up-rated for increased energy production, and existing repair methods can worsen vibration and constrain components to suboptimal positions.
Innovation Solution
A clamp apparatus with a ball subassembly, clamp jaws, and a biasing mechanism that allows for controlled movement and secure attachment of jet pump sensing lines to a diffuser shell, enabling rotation, translation, and re-orientation while preventing excessive vibration-induced stress, fabricated from materials resistant to nuclear reactor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding is used to attach sensing lines to supports, then the sensing lines are securely fixed, but the components become susceptible to vibration-induced cracking and stress-corrosion damage
Solution Approach 1:
The clamp apparatus divides the attachment system into separate components: a clamp body that engages with the support and a sensing line clamping mechanism that secures the sensing line. This segmentation allows each component to be optimized independently, with the clamp providing rigid support attachment and the clamping mechanism providing flexible, vibration-resistant sensing line securation without welding.
Solution Approach 2:
The invention changes the attachment parameter from permanent welding to a mechanical clamping system with adjustable clamping force. The clamp apparatus uses a screw mechanism or spring-loaded jaws to apply controlled pressure, allowing the sensing line to be securely held while accommodating thermal expansion and vibration without the brittleness of welded joints.
2Strength
If rigid welding is used to secure sensing lines, then the sensing lines are firmly attached, but the components cannot accommodate movement or repositioning
Solution Approach 1:
The clamp apparatus incorporates dynamic elements including adjustable clamping mechanisms and movable clamping jaws that can be positioned along the sensing line. This allows the attachment point to be repositioned if needed while maintaining secure attachment, providing adaptability that rigid welding cannot offer.
Solution Approach 2:
The clamp apparatus acts as an intermediary between the support structure and the sensing line. It provides a mechanical interface that can be adjusted and repositioned, mediating between the need for firm attachment and the need for adaptability. The clamp body attaches to the support while the clamping mechanism secures the sensing line, allowing independent adjustment of each interface.
3Strength
If sensing line supports are welded to diffuser shells, then the supports are securely mounted, but repair and replacement require plant outages
Solution Approach 1:
The clamp apparatus segments the mounting system into a clamp body that attaches to the diffuser shell and a sensing line clamping mechanism. This segmentation allows the clamp body to be securely mounted to the diffuser shell while the sensing line attachment remains accessible and replaceable without removing the entire mounting structure, enabling repairs during operation.
Solution Approach 2:
The invention extracts the sensing line attachment function from the permanent welded support structure. The clamp apparatus can be independently installed and removed, allowing the sensing line to be accessed, replaced, or repaired without disturbing the diffuser shell mounting or requiring plant outages for refueling and repair.
4Productivity
If components are designed for high energy production, then power plant output is increased, but vibration levels increase causing premature damage
Solution Approach 1:
The clamp apparatus incorporates vibration-mitigating features in its design, including flexible clamping mechanisms and damping elements that cushion the sensing line against vibration-induced stress before damage can occur. This beforehand cushioning protects the sensing line from the increased vibration levels associated with high energy production operations.
Solution Approach 2:
The invention changes the mechanical parameters of the attachment system from rigid welded joints to a flexible clamping system with controlled stiffness. This parameter change allows the attachment to accommodate vibration while maintaining secure mounting, enabling the system to operate at higher energy production levels without premature vibration-induced damage.
Data Source
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AI summary
Clamps are used to clamp two components together, with a degree of freedom of motion between the clamped components, including both rotational and translational motion. Said clamps include a ball subassembly that holds a component and allows rotation and twisting of the component within the clamp. Said clamps further include jaws holding the ball subassembly and a biasing element that permits tightening of the clamp. Such clamps may clamp a BWR jet pump sensing line to a diffuser as a repair or installation of a sensing line support.