Fluid Diode Piping for Backflow Control in Sodium-Cooled Reactors
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Solution Overview
Problem
Sodium-cooled nuclear reactors face backflow issues when one electromagnetic pump fails, causing fluid to flow back into non-operational pumps, which reduces reactor power output and requires unnecessary reactor trips.
Innovation Solution
A backflow reduction pipe with a tubular section and fluid diode sections, designed to restrict backflow by creating a pressure gradient in the backflow direction without disrupting normal flow, is integrated into the electromagnetic pump assembly. The fluid diode sections have varying diameters and lengths to enhance resistance in the backflow direction, preventing fluid from reversing into inoperable pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic pumps are used to flow sodium fluid in a nuclear reactor, then coolant circulation is achieved, but backflow occurs when one pump fails, reducing power output
Solution Approach 1:
A backflow reduction pipe with fluid diode sections is introduced as an intermediary component between the heat exchanger and reactor core. This pipe includes sections with varying diameters (first section with second diameter, second section with third diameter) that create asymmetric flow resistance, allowing forward flow while blocking backflow. The intermediary structure enables the system to maintain reliability by preventing backflow into failed pumps without sacrificing the productivity of operational pumps.
2Reliability
If backflow restriction is implemented using traditional valves or mechanisms, then backflow is prevented, but device complexity and potential failure points increase
Solution Approach 1:
Instead of using mechanical valves or complex control systems, the invention changes the geometric parameters of the pipe itself. The backflow reduction pipe features fluid diode sections with specific diameter variations (second diameter in first section, third diameter in second section) that create passive hydrodynamic resistance. This parameter-based approach prevents backflow through fluid dynamics alone, avoiding mechanical complexity while maintaining high reliability.
3Ease of manufacture
If the pipe diameter is uniform throughout, then manufacturing is simplified, but backflow restriction effectiveness is reduced
Solution Approach 1:
The backflow reduction pipe applies local quality by having different diameter sections at specific locations along the pipe length. The first section has a second diameter at its largest point, while the second section has a third diameter at its largest point, with the second diameter being larger than the third diameter. This localized geometric variation creates the necessary asymmetric flow resistance for backflow prevention while minimizing overall manufacturing complexity, as only specific sections require precision shaping rather than the entire pipe.
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 solution effectively restricts backflow, maintaining 75% of rated power output with three operational pumps and preventing unnecessary reactor trips, while ensuring proper coolant mixing and increasing the reactor's operational efficiency and reliability.
Implementation Method 1
designed to restrict backflow by creating a pressure gradient in the backflow direction without disrupting normal flow
Data Source
AI summary
A sodium-cooled nuclear reactor includes at least one electromagnetic pump assembly and a backflow reduction pipe. The backflow reduction pipe may include an inlet, an outlet, at least one tubular section having a first length and a first diameter, and at least one fluid diode section between the inlet and the outlet.