Sealing Plug Assembly for Junction Tubing in Nuclear Reactors
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Solution Overview
Problem
Existing sealing assemblies for nuclear reactor steam generators require continuous inflation monitoring and have insufficient mechanical resistance to pressure and temperature, making them unreliable for repeated and long-duration use or accidental situations.
Innovation Solution
A sealing assembly featuring a passive annular seal with a vacuum-deployable mechanism, combined with static and flat annular seals, secured to a composite or metal alloy lid with hinged panels, ensuring reliable sealing without continuous inflation monitoring and enhanced resistance to pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inflatable shutter with annular seals is used for sealing the junction pipe opening, then the sealing function is achieved, but the mechanical resistance to pressure and temperature becomes insufficient for repeated and long-duration use
Solution Approach 1:
The patent changes the physical state and material properties of the sealing system by replacing inflatable rubber seals with rigid or semi-rigid seals made of materials such as PTFE (polytetrafluoroethylene) or metal alloys. These materials maintain their sealing properties under high pressure and temperature conditions without requiring continuous inflation, thereby resolving the contradiction between sealing reliability and mechanical strength.
Solution Approach 2:
The shutter assembly employs composite construction combining rigid structural components (metal or composite lid) with specialized sealing materials (PTFE, metal gaskets). This composite approach allows the structure to withstand high pressure and temperature while maintaining effective sealing, addressing both the reliability and strength requirements simultaneously.
2Ease of operation
If a shutter made of several parts assembled inside the water box is used, then the shutter can be introduced through a manhole, but the device complexity increases and requires continuous inflation monitoring
Solution Approach 1:
The shutter is divided into modular components: a lid portion, a sealing assembly, and a flange portion. These segmented parts can be assembled separately and installed through the manhole, maintaining ease of operation while reducing overall complexity by using standardized, pre-fabricated components that require no continuous monitoring.
Solution Approach 2:
The sealing system is designed to be self-containing and self-sealing, eliminating the need for external inflation units and continuous monitoring. The rigid or semi-rigid seals maintain their sealing function passively through material properties and geometric design, reducing device complexity and operational burden.
3Reliability
If multiple static seals and a passive seal with vacuum deployment are used, then the sealing reliability is improved, but the ease of manufacture decreases
Solution Approach 1:
Multiple sealing functions are merged into an integrated sealing assembly that combines the lid, sealing elements (including PTFE or metal seals), and flange into a single pre-assembled unit. This merging maintains high sealing reliability through multiple sealing mechanisms while simplifying manufacture by allowing the entire assembly to be pre-fabricated and tested before installation, reducing on-site manufacturing 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
The solution provides a reliable, easy-to-implement sealing assembly that reduces operator intervention time in hostile environments, ensuring effective sealing and increased resistance to pressure, thereby improving safety and efficiency during maintenance operations.
Implementation Method 1
a passive annular seal provided with at least one outer lip, said seal being deformable between a retracted position by placing said seal under vacuum during the positioning of the lid on the fixing ring
Implementation Method 2
it being possible, after having fixed the lid on the fixing ring, to deploy said passive seal by placing the said seal under atmospheric pressure in order to ensure sealing
Data Source
Figure 1~2
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AI summary
The invention relates to a sealed stopper (10) for an opening in a junction tubing (6) between a housing and a pipe that comprises a fixation ring. The stopper (10) includes a rigid lid (11) and a sealing assembly (20) carried by said lid (11) including a passive annular seal (25) with at least one inner annular chamber (26), a first static annular seal (30), a second static annular seal (35), and a flat annular seal (40) ensuring the tightness of the opening in said tubing.