Modular Flow Plates for Nuclear PCCS Manifold Distribution
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Solution Overview
Problem
Existing Passive Containment Cooling Systems (PCCS) in nuclear power plants face inefficiencies due to uneven distribution of highly energetic fluids, such as saturated steam and superheated non-condensable gases, which reduces overall system efficiency, especially during transient events like loss of coolant or superheated containment.
Innovation Solution
A modular fluid flow control system using swappable plates with varying geometries, such as chevron, perforated, and voided designs, retained by a grooved ledge structure within the upper manifold, allowing for precise control and redistribution of fluid flows to evenly distribute energetic fluids across PCCS tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional PCCS upper manifold is used without flow control plates, then the structure is simple and easy to manufacture, but the fluid flow distribution is uneven causing central tubes to be overwhelmed and reducing system efficiency
Solution Approach 1:
The upper manifold is segmented into multiple flow zones by inserting adjustable plates at different positions. Each plate divides the manifold into separate flow paths, allowing independent control of fluid distribution to different PCCS tube bundles. This segmentation enables even distribution of high-velocity steam and gas flows across all tubes, preventing central tube overload and improving overall system efficiency.
Solution Approach 2:
The plates are designed to be adjustable and repositionable within the manifold, allowing dynamic modification of flow characteristics. The plates can be rotated or repositioned along the manifold length to optimize flow distribution under different operating conditions (normal operation vs. transient events). This dynamic capability enables the system to adapt to varying flow rates and maintain efficient heat transfer across all PCCS tubes.
2Adaptability or versatility
If fixed geometry plates are used in the manifold, then the manufacturing is simpler, but the system cannot adapt to different flow conditions during normal and transient operations
Solution Approach 1:
The plates are designed with multiple functional surfaces including chevron patterns, perforations, and voided sections that can serve different flow control functions. The same basic plate geometry can be rotated or repositioned to create different flow resistance patterns, allowing a single plate design to handle multiple operating conditions. This multi-functionality reduces the need for multiple specialized plate types while maintaining adaptability.
Solution Approach 2:
The plates feature asymmetric geometries with chevron patterns, offset perforations, and non-uniform thickness distributions that create directional flow control. These asymmetric features generate specific flow patterns (swirl, diffusion, or straightening) depending on the plate's orientation and position in the manifold, enabling precise control of fluid distribution to match different operational requirements without requiring completely different plate designs.
3Manufacturing precision
If no flow control mechanism is added to the manifold, then the device complexity remains low, but the fluid flow remains uneven and cannot be redistributed to achieve even cooling
Solution Approach 1:
The plates are designed to be self-adjusting through their geometric features. The chevron patterns, perforations, and voided sections create pressure differentials and flow resistance variations that automatically balance the flow distribution across all manifold outlets. The plates work passively with the fluid dynamics themselves, using the flow's own energy to achieve even distribution without requiring external control systems or complex actuation mechanisms.
Solution Approach 2:
The plates serve as intermediary elements between the manifold inlet and the PCCS tube bundles. They mediate the high-velocity, uneven flow from the inlet by diffusing and redistributing it across multiple flow paths before reaching the tubes. The plates translate the concentrated inlet flow into distributed outlet flows, acting as a flow conditioning interface that improves distribution uniformity without requiring modification of the inlet or tube structures.
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 modular system enhances fluid flow distribution, preventing overwhelming of central tubes and ensuring even cooling, thereby improving the overall efficiency and reliability of the PCCS system by allowing for fine-tuning of flow characteristics during both normal and transient conditions.
Implementation Method 1
a chevron plate may be placed directly below an inlet for a high-velocity and high-temperature steam and non-condensable gas mixture in a PCCS upper manifold, and the chevron plate may deflect and redirect the flow to diffuse it along an entire length of the upper manifold
Implementation Method 2
Plates can present a variety of geometries, including perforations, labyrinthine passages, chevrons, voids, mixing tabs, swirl vanes, and solid, flat planes to enhance, impede, make turbulent, mix, direct, and/or change fluid flow
Implementation Method 3
Because PCCS tubes 12 may be submerged in a coolant, like chilled water, the increased surface area of PCCS tubes 12 may cool and/or condense fluid received into PCCS 10
Data Source
AI summary
Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.