Nuclear Filter Circulation System Preventing Thin Skin Effect
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Solution Overview
Problem
The 'thin skin effect' in nuclear reactor filtration systems leads to significant pressure drops and potential clogging, disrupting the low-pressure safety injection system, particularly due to the accumulation of fibers and particles, which existing solutions struggle to prevent effectively without increasing costs or requiring system interruptions.
Innovation Solution
A circulation system that injects a prevention fluid along a specific axis and angle on the filter surface to agitate fibers and particles, preventing the formation of a homogeneous thin skin, thereby maintaining fluid flow and system functionality without operator intervention or increased filter size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If large filtration areas are installed and sized to combat the thin-skin effect, then the pressure drop is reduced, but the site planning constraints and filter development costs increase
Solution Approach 1:
The invention introduces a preliminary action by injecting a fluid (such as water or air) onto the filter surface before the thin skin effect can fully develop. This pre-action disturbs the fiber accumulation process, preventing the formation of a dense, homogeneous fiber layer that would cause high pressure drop. The injection occurs at specific locations and angles to maximize disruption of fiber deposition patterns.
Solution Approach 2:
The invention changes the physical parameters of the filtration system by introducing an additional fluid phase and altering the flow dynamics on the filter surface. By controlling the injection parameters (flow rate, angle, location), the system modifies how fibers are deposited and distributed, transforming the filter surface conditions to prevent thin skin formation without increasing the physical filter area.
2Reliability
If filter cleaning is performed by injecting fluid from inside to outside, then the thin skin effect is removed, but the system must be shut down requiring operator intervention
Solution Approach 1:
The invention applies preliminary action by continuously or periodically injecting fluid to prevent thin skin formation in the first place, rather than waiting for the filter to clog and then cleaning it. This preventive approach maintains filter functionality throughout operation without requiring shutdowns for maintenance.
Solution Approach 2:
The invention ensures continuity of useful action by implementing a prevention mechanism that operates continuously or periodically alongside the normal filtration process. The fluid injection system runs concurrently with filter operation, maintaining filter effectiveness without interrupting the safety injection system's functionality.
3Stress or pressure
If the filter surface area is increased to prevent thin skin effect, then the pressure losses remain acceptable, but the costs related to filter development and site planning increase
Solution Approach 1:
The invention introduces an intermediary substance (fluid such as water or air) that acts as a mediator between the incoming fiber-laden flow and the filter surface. This intermediary fluid disrupts the direct deposition of fibers onto the filter, preventing thin skin formation without requiring additional filter material or increased surface area.
Solution Approach 2:
The invention changes the operational parameters of the filtration system by adding a controlled fluid injection parameter. This allows optimization of pressure loss prevention through flow dynamics control rather than through increasing physical filter dimensions, thereby reducing the quantity of filter material and space required.
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 system effectively prevents the thin skin effect by maintaining fluid flow and system functionality, reducing the risk of clogging and pressure drops, and minimizing costs associated with filter size and operational disruptions.
Implementation Method 1
A circulation system that injects a prevention fluid along a specific axis and angle on the filter surface to agitate fibers and particles, preventing the formation of a homogeneous thin skin
Implementation Method 2
an inlet arranged such that a liquid loaded with fibers and particles accumulates in the collection zone, a circulation element having a suction fluidly connected to the supply zone, and a liquid circulation circuit supplied by the circulation element
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a liquid circulation system (22) of a nuclear facility, comprising: - a volume (24), comprising a filter (30) dividing the volume (24) into a collecting zone (32) in which a liquid (28) loaded with fibres and particles accumulates, and a feed zone (34), and - a circuit (46) for circulating the liquid (28), allowing the recirculation of a liquid flow accumulating in the collection zone (32). This circulation system comprises a prevention system (48) for preventing the formation of a thin homogeneous skin of fibres and particles over all or part of the filter surface (30), the prevention system (48) comprising an injection member (50) injecting a fluid for preventing the thin skin effect on at least a part of the filter (30).