Backflow Reduction Piping With Fluid Diodes for Sodium Reactor Pumps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In sodium-cooled nuclear reactors, the failure of one electromagnetic pump can cause fluid backflow into the outlets of non-operational pumps, disrupting the fluid flow and necessitating a reactor trip, which reduces power output and operability.
Innovation Solution
The implementation of a backflow reduction pipe with tubular sections and fluid diode sections that restrict backflow by creating a pressure gradient, utilizing varying diameters and geometries to maintain forward flow without moving parts or additional control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic pumps are used to flow sodium fluid in a nuclear reactor, then fluid flow from heat exchanger to reactor core is achieved, but backflow into non-operational pump outlets occurs when a pump fails
Solution Approach 1:
A backflow reduction pipe is introduced as an intermediary component between the heat exchanger and reactor core. This pipe includes a fluid diode section that selectively allows forward flow while blocking backflow, thereby mediating the harmful backflow effect without disrupting normal pump operation
Solution Approach 2:
The fluid diode section utilizes geometric parameter changes - specifically varying diameters (first diameter in first direction, second diameter in second direction) to create asymmetric flow resistance. This allows the same structure to facilitate forward flow while resisting backflow through parameter asymmetry
2Reliability
If backflow is prevented using traditional valves or control systems, then backflow is restricted, but device complexity increases
Solution Approach 1:
The fluid diode section is designed to automatically prevent backflow through its asymmetric geometry without requiring external control systems, valves, or power sources. The structure itself provides the backflow prevention function, making the system self-regulating and eliminating complex control mechanisms
Solution Approach 2:
Traditional mechanical backflow prevention devices (valves, actuators, control systems) are replaced with a passive geometric structure. The asymmetric diameter configuration creates inherent flow directionality through fluid dynamics principles rather than mechanical control
3Productivity
If reactor operation continues with three pumps instead of tripping, then power output is maintained at 75% capacity, but backflow disrupts fluid flow
Solution Approach 1:
The backflow reduction pipe is installed in advance to prevent backflow before it can disrupt system operation. By having the fluid diode section already in place, the system can immediately maintain stable fluid flow when a pump fails, enabling continued operation at reduced capacity without flow disruption
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 backflow reduction pipe enhances reactor operability and power output by maintaining flow direction during pump failures, allowing operation at 75% of rated power with three pumps, increasing core flow by 18% and reactor power by 54 MW, and preventing unnecessary reactor trips.
Implementation Method 1
fluid diode sections that restrict backflow by creating a pressure gradient
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.