Wedge Retention Apparatus for Nuclear Jet Pump Vibration
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Solution Overview
Problem
Jet pump assemblies in nuclear power plants experience vibration due to high velocity water flow and heat, leading to wear between metal components, which existing solutions fail to adequately address.
Innovation Solution
A retention apparatus with a wedge element and engagement assembly, featuring a deflectable spring that applies a retention force to resist movement of the flow element, including a wedge element with oblique surfaces and a tensioning apparatus with a coil spring to absorb and dampen vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a metallic wedge is used to resist vibration of the inlet mixer, then vibration resistance is improved, but component wear increases due to metal-to-metal contact under high velocity water flow and heat
Solution Approach 1:
The patent introduces a non-metallic wedge element as an intermediary between the metallic inlet mixer and restrainer bracket. This non-metallic material acts as a mediator that reduces direct metal-to-metal contact, thereby decreasing wear while still providing the necessary vibration resistance through its wedge geometry and friction properties.
Solution Approach 2:
The patent changes the material parameter of the wedge element from metallic to non-metallic. This material parameter change fundamentally alters the interaction characteristics between contacting surfaces, reducing wear rates while maintaining the friction and normal force necessary for vibration resistance.
2Loss of substance
If a non-metallic wedge element is used to reduce wear, then component wear is reduced, but vibration resistance may be compromised without additional retention mechanisms
Solution Approach 1:
The patent employs a dynamic retention apparatus with a spring element that applies a variable normal force to the non-metallic wedge. This dynamic mechanism adjusts the retention force to maintain stable engagement of the wedge between the inlet mixer and restrainer bracket, ensuring vibration resistance is preserved despite the non-metallic material's different friction characteristics.
Solution Approach 2:
The retention apparatus with spring element acts as an intermediary mechanism that ensures proper engagement and positioning of the non-metallic wedge. This intermediary system compensates for any potential loss in vibration resistance by actively maintaining the wedge in its engagement position under varying operational conditions.
3Device complexity
If gravity alone is used to maintain the wedge in place, then device complexity is minimized, but reliability is insufficient under high velocity water flow forces and vibration
Solution Approach 1:
The patent transitions from a static gravity-dependent retention system to a dynamic spring-based retention system. The spring element actively applies a controlled normal force to the wedge, ensuring reliable engagement under high velocity water flow and vibration conditions, while adding only minimal complexity to the overall device structure.
Solution Approach 2:
The spring element applies a preliminary retentive force to the wedge element before high velocity water flow and vibration occur. This preliminary anti-action counteracts the destabilizing forces that would otherwise cause the wedge to disengage, ensuring reliable operation under extreme conditions.
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 retention apparatus effectively reduces vibration-induced wear by applying a compressive retention force, maintaining the wedge element's engagement with the flow and brace elements, thereby minimizing component wear and stabilizing the jet pump assembly during operation.
Implementation Method 1
The engagement assembly includes a deflectable element such as a spring that is structured to apply a retention force in an engagement direction of the wedge element
Implementation Method 2
a wedge element with oblique surfaces and a tensioning apparatus with a coil spring to absorb and dampen vibrations
Implementation Method 3
a tensioning apparatus with a coil spring to absorb and dampen vibrations
Data Source
AI summary
An improved retention apparatus includes a wedge element that is disposed between a brace element and a flow element of a nuclear reactor system. The retention apparatus further includes an engagement assembly that is engaged with the wedge element and that is structured to engage at least one of the brace element and the flow element. The engagement assembly includes a deflectable element such as a spring that is structured to apply a retention force in an engagement direction of the wedge element to resist movement of the flow element during operation of the nuclear reactor system, such as movement due to vibration.