Nuclear Reactor Deposit Model for Heat Transfer Prediction
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Solution Overview
Problem
Corrosion and reduced heat transfer efficiency in nuclear reactors due to deposits on heat transfer surfaces, which are complex and not accurately modeled by existing theories, leading to potential thermal and corrosion damage.
Innovation Solution
A method to model the deposit layer on heat transfer surfaces using a distribution of channels with varying radii, where each new layer increment is defined by a minimum radius and radius increment, representing the observed structure and porosity, allowing for more realistic simulation of heat transfer processes and deposit evolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing theories are used to model deposit layers on heat transfer surfaces, then the modeling process is simple, but the accuracy of heat transfer prediction is insufficient
Solution Approach 1:
The patent models the deposit layer as a porous structure with channels of varying radii, representing the actual sponge-like nature of crud deposits. This approach captures the complex internal structure including capillary regions and steam chimneys, enabling more accurate heat transfer prediction while maintaining manageable model complexity through systematic geometric representation
Solution Approach 2:
The patent applies different channel radius distributions to different regions of the deposit layer, with smaller radii near the heat transfer surface and larger radii toward the outer surface. This local variation in geometric properties accurately represents the non-uniform structure of deposits and their impact on heat transfer at different locations
2Manufacturing precision
If deposit layer is modeled with uniform structure, then the modeling is simplified, but the actual varied structure of deposits is not captured
Solution Approach 1:
The patent divides the deposit layer into multiple horizontal layers, each with its own channel radius distribution characteristics. This segmentation allows the model to capture the vertical variation in deposit structure from the dense inner layer near the heat transfer surface to the fluffier outer layer, improving structural representation without overwhelming complexity
Solution Approach 2:
The patent varies key geometric parameters including channel radius, porosity, and layer thickness across different depths of the deposit layer. These parameter changes reflect the actual evolution of deposit structure over time and position, enabling accurate representation of the non-uniform deposit morphology
3Reliability
If corrosion products accumulate on heat transfer surfaces, then the realism of the model increases, but heat transfer efficiency decreases
Solution Approach 1:
The patent converts the harmful effect of deposit accumulation into a beneficial modeling opportunity by systematically representing the deposit structure with channels and pores. This allows the model to capture both the heat transfer degradation caused by deposits and the complex physical processes occurring within the deposit layer, including capillary action and steam generation
Solution Approach 2:
The patent introduces an intermediate porous structure model between the heat transfer surface and the bulk fluid, representing the deposit layer as a distinct zone with its own geometric and physical properties. This intermediary layer mediates the heat transfer process, allowing separate characterization of conduction through the deposit matrix and convection within the channels
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 approach improves the accuracy of heat transfer modeling, reducing the risk of thermal damage and extending the lifespan of reactor components by better understanding and managing deposit buildup.
Implementation Method 1
heat transfer through the modeled deposit layer is primarily a combination of conduction through the deposit and water matrix
Implementation Method 2
convection through water in the matrix which is converted to steam
Implementation Method 3
water in the matrix which is converted to steam
Implementation Method 4
the water to be converted to steam, the chemical, physical and thermodynamic processes will work in concert
Implementation Method 5
The sponge-like nature of the deposit layer creates conditions corresponding to capillary water movement
Implementation Method 6
a heat source such as a nuclear core or furnace and a coolant circuit
Implementation Method 7
respective coolant piping circuits transport the heated water or steam
Data Source
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AI summary
A method of operating a nuclear reactor is provided. The method includes defining a layer increment (24) of a deposit layer (10) modeling a deposit on a heat transfer surface (12) of the nuclear reactor (200); periodically updating a thickness of the deposit layer (10) by adding the layer increment (24) to the deposit layer (10); recalculating properties of the deposit layer (10) after each layer increment (24) is added to the deposit layer (10); determining a temperature related variable of the heat transfer surface (12) as a function of the recalculated properties of the deposit layer (10); and altering operation of the nuclear reactor (200) when the temperature related variable of the heat transfer surface (12) reaches a predetermined value. A method of modeling a deposit on a heat transfer surface (12) of a nuclear reactor (200) is also provided.