PDC Protective Coatings for Spent-Fuel Canister Corrosion Cracking
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Solution Overview
Problem
The structural integrity of steel canisters used for storing spent nuclear fuel is compromised by chloride-induced stress corrosion cracking (CISCC) due to the formation of deliquescent salt moisture, posing a significant safety concern for long-term storage.
Innovation Solution
A protective coating is prepared by dissolving a dispersant in an organic solvent, adding polymer-derived ceramic (PDC) and metal oxides, and applying the solution onto metal substrates using spray coating, which includes passive and active fillers to enhance corrosion resistance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional protective coatings are applied to steel canisters, then corrosion resistance is improved, but the coating may delaminate or crack under thermal stress and mechanical loading
Solution Approach 1:
The patent transforms the coating material from organic polymer to inorganic ceramic through chemical composition change. The preceramic polymer undergoes pyrolysis to form a ceramic coating with fundamentally different properties - inorganic, non-delaminating, and thermally stable structure that eliminates the delamination issue inherent in organic coatings while maintaining protection functionality
Solution Approach 2:
The patent creates a composite structure by incorporating ceramic particles (alumina, zirconia, silica) into the preceramic polymer matrix. This composite approach combines the processability of polymers with the thermal and mechanical stability of ceramics, producing a coating that resists both corrosion and thermal/mechanical stress
2Duration of action of stationary object
If alloy composition is improved to increase service lifetime, then corrosion resistance is enhanced, but material cost and complexity increase
Solution Approach 1:
The patent extracts the protection function from the substrate material itself and places it in a separate coating layer. Instead of making the steel canister alloy more complex and expensive, a relatively simple preceramic polymer coating is applied that provides the necessary corrosion and thermal protection, keeping the base material simple and cost-effective
3Strength
If processing methods like shot peening or laser peening are used to introduce compressive residual stress, then fatigue resistance is improved, but permanent deformation or plastic deformation of the surface layer occurs
Solution Approach 1:
The patent applies the protective coating before the canister is placed in service, creating a protective layer that prevents corrosion initiation and propagation from the outset. This preliminary protection eliminates the need for subsequent stress-induced strengthening treatments that would deform the surface, as the ceramic coating provides inherent corrosion and fatigue resistance
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 coating provides superior corrosion resistance and mechanical properties, reducing corrosion current density by an order of magnitude and maintaining integrity under varying temperatures, thus extending the service life of steel canisters.
Implementation Method 1
applying the solution onto metal substrates using spray coating
Implementation Method 2
reducing corrosion current density by an order of magnitude
Data Source
AI summary
Methods for preparing and using at least one protective coating on industrial articles and storage systems are disclosed. In one example, the industrial components are dry storage cannisters for spent nuclear fuel or other waste materials. An example method for preparing at least one protective coating on dry storage cannisters for spent nuclear fuel and waste includes dissolving a dispersant in an organic solvent. The method further includes adding a polymer-derived ceramic (PDC) to the organic solvent and dissolved dispersant to create a pre-ceramic solution. The method further includes applying the pre-ceramic solution on a metal and/or alloy of industrial articles and storage systems such as the dry storage cannisters.