Porous Precursor Diffusion Device for Uniform Clad Coating
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Solution Overview
Problem
The increase in intermittent energy sources, particularly renewable energies, leads to more frequent power transients in nuclear power plants, causing Pellet Clad Interaction (PCI) issues, such as mechanical tension and stress corrosion cracking, which can result in clad failure and fuel dispersion, and existing methods for depositing internal layers to mitigate these issues suffer from large thickness heterogeneities.
Innovation Solution
A precursor diffusion device with a porous element that generates an aerosol of precursor fluid by fragmenting it when the pressure exceeds a threshold, allowing controlled and homogeneous deposition of a protective layer on the growth surface, preventing losses and ensuring uniformity, and is suitable for use in chemical vapor deposition processes at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mature deposition method is used to deposit an internal layer on the clad, then the deposition process is simple and reliable, but large heterogeneities in thickness occur over centimetric or metric lengths
Solution Approach 1:
The patent employs a porous diffusion device where the precursor fluid passes through a porous element. The porous structure enables controlled diffusion of the precursor, ensuring uniform distribution across the growth surface and achieving homogeneous layer thickness without requiring complex deposition equipment
Solution Approach 2:
The porous element acts as an intermediary between the precursor fluid reservoir and the growth surface. It mediates the transport of precursor molecules through diffusion, transforming the direct deposition process into a controlled diffusion process that ensures uniform thickness distribution
2Productivity
If the precursor fluid pressure is increased to improve diffusion rate, then the deposition speed increases, but uncontrolled precursor fluid passage occurs leading to losses
Solution Approach 1:
The patent utilizes pressure as a controllable parameter to regulate precursor fluid diffusion. By maintaining pressure below the threshold value, the system achieves controlled diffusion at optimal rates without excessive precursor fluid passage, balancing deposition speed with substance conservation
Solution Approach 2:
The system incorporates a threshold pressure mechanism that provides feedback control. When pressure approaches the threshold, diffusion is automatically regulated to prevent uncontrolled passage, ensuring consistent deposition rates and minimizing precursor fluid losses
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 effectively limits deformation and prevents clad failure by uniformly depositing a protective layer, reducing the risk of fuel dispersion and stress corrosion cracking, while maintaining the integrity of the clad and fuel pellets during power transients.
Implementation Method 1
allow said precursor fluid to pass through a thickness of the porous element counted between said inner surface and said diffusion surface as long as a pressure of the precursor fluid contained in the receiving enclosure is strictly higher than a threshold pressure
Implementation Method 2
the precursor fluid which passes through the thickness of the porous element generates, from the diffusion surface, an aerosol by fragmentation of the precursor fluid
Implementation Method 3
prevent the precursor fluid from passing through said thickness of the porous element when the pressure of the precursor fluid contained in the receiving enclosure is lower than said threshold pressure
Data Source
AI summary
A precursor diffusion device configured to diffuse a growth precursor towards an external growth surface included on an external growth member, the diffusion device including a container including at least one porous element having a porosity configured to allow or prevent the passage of a precursor fluid through a thickness of the porous element, the porous element being configured so that the precursor fluid which passes through the thickness of the porous element generates an aerosol by fragmentation of the precursor fluid, the aerosol being formed of droplets of the precursor fluid. Also, a method for depositing a layer on a growth surface by such a diffusion device.