Fibrous Leak Detection Device for Sodium Conduits
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Solution Overview
Problem
Existing leak detection devices for sodium transport conduits in nuclear reactors face challenges such as difficulty in conforming to complex shapes, risk of oxidation, and malfunction due to thermal expansion, which hinder accurate and timely leak detection.
Innovation Solution
A leak detection device comprising a layer of fibrous insulating material coated with a fibrous conductive material, such as carbon or graphite felt, that extends over the conduit, allowing for impedance measurement between the conduit wall and the conductive material, which is resistant to oxidation and thermal deformation, and can be securely fastened to adapt to complex shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid insulating shell with metal wires or strips is used to detect leaks, then electrical contact detection is enabled, but the device cannot perfectly match complex conduit surfaces
Solution Approach 1:
The patent replaces rigid insulating shells with flexible insulating sheets that can be wrapped around conduits of any shape. The flexible nature allows the sheet to conform to complex surfaces while maintaining the insulating barrier necessary for leak detection through electrical contact.
Solution Approach 2:
The invention uses a composite structure combining flexible insulating material (such as rubber or plastic sheets) with conductive elements (metal wires or conductive coatings). This composite approach maintains the insulating properties needed for detection while adding flexibility to match complex conduit geometries.
2Reliability
If metal grids or fabrics are wound around insulating sheets, then conductive contact is achieved, but the grid may penetrate the insulating sheet causing false contacts
Solution Approach 1:
The patent introduces an intermediate layer or protective coating between the metal conductive elements and the insulating sheet. This intermediary prevents direct penetration while maintaining electrical contact capability, eliminating false contacts caused by grid penetration into the insulating material.
Solution Approach 2:
Instead of using rigid metal grids that may penetrate, the invention uses conductive coatings or flexible conductive layers that replicate the necessary electrical contact function without the mechanical penetration problem. The conductive coating conforms to the insulating sheet surface without penetrating it.
3Reliability
If metallic conductive elements are used, then electrical conduction is achieved, but oxidation forms films that delay leak detection
Solution Approach 1:
The patent employs sacrificial protective coatings on metal conductive elements that are designed to oxidize preferentially. These coatings act as a first line of defense that degrades over time, but the underlying conductive elements remain protected and functional for the main service life of the device.
Solution Approach 2:
The invention uses conductive materials with high oxidation resistance (such as graphite, carbon, or noble metals) or applies protective coatings that create an inert barrier between the metal and oxygen environment, preventing oxide film formation that would delay leak detection.
4Reliability
If metallic conductive elements are used, then electrical conduction is achieved, but thermal expansion causes deformation and malfunction
Solution Approach 1:
The patent changes the material parameters of the conductive elements by selecting materials with low thermal expansion coefficients (such as graphite, carbon fiber, or Invar alloy). This parameter change ensures dimensional stability across the temperature range experienced by the conduit without compromising electrical conduction capability.
Solution Approach 2:
The invention uses composite structures combining metals with low thermal expansion materials or uses metal-ceramic composites that maintain both electrical conductivity and dimensional stability under thermal variation, preventing deformation and malfunction.
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 enables reliable and timely detection of sodium leaks, reduces thermal losses, and protects against operator burns, while maintaining operational integrity across varying temperatures.
Implementation Method 1
a layer of fibrous insulating material and a layer of fibrous (or filamentary) conductive material which extends over the layer of fibrous insulating material
Implementation Method 2
a layer of fibrous (or filamentary) conductive material which extends over the layer of fibrous insulating material, the fibrous conductive material consisting essentially of a carbon or graphite felt
Data Source
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AI summary
The invention relates in particular to a method for coating a fluid transport or storage conduit with a fluid leak detection device comprising a layer of fibrous insulating material arranged to surround the conduit and a layer of conductive material extending alongside the layer of insulating material, said conductive material being essentially formed by carbon or graphite fibres. According to the invention, the layer of insulating material is solidly connected to the wall of the conduit by banding same using links.