Nuclear Fuel Assembly Coating Uniformity via Horizontal Capillary Application
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Solution Overview
Problem
Current nuclear reactor fuel assembly manufacturing methods face inefficiencies due to non-uniform lacquer coating, high material and energy consumption, complex equipment requirements, and low automation, leading to quality issues and increased costs.
Innovation Solution
A method using a water-soluble lubricant composition of nonylphenol ethoxylate and monobasic unsaturated fatty acids for a protective coating on fuel elements, applied and washed off efficiently during assembly, eliminating the need for drying and complex lacquer application processes, ensuring a uniform and adherent coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyvinyl water-based lacquer is applied by immersion in vertical position, then fuel element surface is protected, but coating thickness becomes non-uniform and protective properties degrade
Solution Approach 1:
The patent inverts the application method from vertical immersion to horizontal movement through a capillary-porous element. The fuel element moves horizontally through the lacquer-saturated element, allowing uniform coating from all surfaces simultaneously, eliminating the thickness gradient caused by vertical immersion.
Solution Approach 2:
The patent introduces a capillary-porous element as an intermediary between the lacquer and the fuel element. This porous element is saturated with lacquer and transfers it uniformly to the fuel element surface through capillary action, ensuring even coating distribution.
2Reliability
If polyvinyl water-based lacquer solution is used for surface treatment, then fuel element protection is achieved, but material consumption increases and handling ability decreases
Solution Approach 1:
The patent uses a capillary-porous element that is saturated with lacquer. The porous structure holds the lacquer and releases it uniformly during the fuel element passage, reducing overall lacquer consumption compared to immersion methods while maintaining protective coating quality.
3Ease of manufacture
If lacquer application equipment is arranged in large spaces, then coating application is possible, but device complexity and automation capability are reduced
Solution Approach 1:
The patent combines the lacquer application function with the existing fuel element movement system. The capillary-porous element is integrated into the assembly line, and fuel elements are coated during their normal horizontal movement, eliminating the need for separate large-space immersion tanks and complex positioning equipment.
4Manufacturing precision
If fuel elements are moved horizontally through capillary-porous element, then uniform coating is achieved, but coating layer blisters and peels during drying
Solution Approach 1:
The patent modifies the lacquer composition by adding specific additives that change its drying characteristics. These additives prevent blistering and peeling during the drying process while maintaining the uniform coating quality achieved through horizontal application.
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
This method enhances manufacturing efficiency and reduces costs while ensuring high-quality fuel assembly production with reduced risk of surface damage and defects, achieving uniform coating and efficient assembly operations.
Implementation Method 1
Cylindrical surface of fuel element is moistened with lacquer in lacquer application area when it passes through tight-fitting elastic capillary-porous element to which lacquer is fed until its pores are filled with lacquer
Implementation Method 2
Water soluble lubricant consisting of nonylphenol ethoxylate in the amount of 20% to 45% and monobasic unsaturated fatty acids in the quantity of 80% to 55% is used as protective coating
Implementation Method 3
protective layer is washed off using water jets under pressure at room temperature
Data Source
AI summary
A method for manufacturing nuclear reactor fuel assembly. The method comprises applying a protective coating on fuel elements, wherein each fuel element is moved through a protective coating application device installed on an assembly stand. The protective coating comprises a water-soluble lubricant consisting of nonylphenol ethoxylate and monobasic unsaturated fatty acids. The method further comprises installing the coated fuel elements into grid cells of an assembly, wherein during the installing, each coated fuel element is moved on the assembly stand in a horizontal direction along its own axis into the grid cells. At least part of the steps of applying a protective coating and installing the coated fuel elements occur simultaneously. After installing the coating, top and bottom nozzles are attached to the assembly. After attaching the top and bottom nozzles, the fuel elements are washed to remove the protective coating from the fuel elements, which are subsequently dried.