Nuclear Sump Strainer Debris Interceptor
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Solution Overview
Problem
Nuclear power plant strainers face challenges in managing differential pressure and debris accumulation during loss of coolant accidents, leading to flow blockages and increased costs due to the need for larger, more complex designs that are costly and difficult to install.
Innovation Solution
A strainer system with a debris interceptor, such as a sacrificial strainer screen or mesh layer, that accumulates debris and opens a bypass flow path when a pre-defined differential pressure is reached, maintaining a clean primary strainer surface and reducing head loss, and a lower density debris bed configuration using stainless steel mesh or cubes to prevent dense debris layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a strainer is designed to remove large amounts of fibrous material and particulate debris, then debris removal effectiveness is improved, but the strainer surface becomes blocked quickly, increasing differential pressure and head loss
Solution Approach 1:
The strainer system is divided into multiple strainer modules, each with its own debris interceptor and primary strainer surface. This segmentation allows debris to be distributed across multiple surfaces, preventing any single surface from becoming completely blocked and maintaining lower differential pressure across the system.
Solution Approach 2:
A debris interceptor is introduced as an intermediary component between the coolant flow and the primary strainer surface. The debris interceptor captures fibrous material and particulate debris first, preventing direct accumulation on the primary strainer surface and thereby reducing head loss while maintaining debris removal effectiveness.
2Loss of energy
If the strainer surface area is increased to reduce debris bed density and head loss, then differential pressure management is improved, but the device size and installation complexity increase
Solution Approach 1:
Instead of using a single large strainer surface, the system employs multiple smaller strainer modules arranged in series or parallel configurations. Each module has its own debris interceptor and strainer surface, achieving the required total filtration area while maintaining manageable individual component sizes and reducing installation complexity.
Solution Approach 2:
The debris interceptor is designed as a sacrificial, replaceable component that captures debris and can be independently maintained or replaced without replacing the entire strainer assembly. This reduces the complexity and cost of maintenance while maintaining effective debris removal.
3Reliability
If a debris bed forms on the strainer surface to trap particulates, then filtration effectiveness is improved, but the debris bed density increases, dramatically increasing differential pressure
Solution Approach 1:
The debris interceptor serves as an intermediary that captures the bulk of fibrous debris and particulate matter before it can form a dense debris bed on the primary strainer surface. This intermediary layer maintains filtration effectiveness while preventing the excessive differential pressure that would result from a dense debris bed formation.
Solution Approach 2:
Different regions of the strainer system have different functions: the debris interceptor region is optimized for capturing fibrous material and forming a loose debris bed, while the primary strainer surface region maintains its filtration function with minimal debris accumulation. This local differentiation allows each region to optimize its performance characteristics.
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 ensures uninterrupted recirculation pump operation by managing differential pressure and reducing debris bypass, maintaining strainer efficiency and preventing flow blockages, while minimizing the required strainer surface area and installation complexity.
Implementation Method 1
the membrane is outfitted to open in response to differential pressure so as to create a bypass flow path
Implementation Method 2
a strainer system for use in a nuclear sump. The primary strainer surface of the primary strainer module includes a debris interceptor which is cooperatively engaged thereto, and comprises a screen or mesh layer
Data Source
AI summary
In accordance with the present invention, there is provided a strainer system for use in a nuclear sump. The strainer system of the present invention includes at least one primary strainer module which defines a primary strainer/filter surface. In the strainer system, the primary strainer surface of the primary strainer module has a debris interceptor which is cooperatively engaged thereto, and may be outfitted with one or more pressure released or activated membranes. In a loss of coolant accident, the debris interceptor, alone or in combination with the pressure activated membrane(s), is adapted to reduce the differential pressure experienced across the strainer system in nuclear power plants with medium to high fiber loads.