Standpipe Flow Tripper Mitigates Acoustic Resonance in Nuclear Reactors
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Solution Overview
Problem
Acoustic resonance in nuclear reactors, particularly in boiling water reactors, causes damage to equipment like steam dryers due to upstream traveling acoustic pressures, which previous methods such as Finite Element Analysis and Helmholtz resonators have not adequately addressed, especially considering the difficulty in supporting large cantilevered devices in nuclear environments.
Innovation Solution
A standpipe flow tripper system is introduced, comprising a pipe with a standpipe connected at an opening and a flow tripper or spoiler extending downstream, disrupting the flow to prevent mutual resonance and acoustic loading without obstructing downstream flow or requiring external support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a Helmholtz resonator is provided on the relief valves to reduce acoustic loading, then the acoustic resonance damage is reduced, but the device becomes large and difficult to support in the nuclear power plant environment
Solution Approach 1:
The invention extracts the flow disruption function from a separate large external device (Helmholtz resonator) and integrates it into a compact tripper element positioned at the standpipe opening. This eliminates the need for large cantilevered bottles while maintaining the acoustic load mitigation function through direct flow tripping at the source.
Solution Approach 2:
The flow tripper is nested within the standpipe structure itself, with the tripper element positioned at the opening where the standpipe connects to the steam line. This nested configuration allows the acoustic mitigation function to be embedded within the existing piping geometry rather than requiring external attachment of large devices.
2Measurement precision
If Finite Element Analysis is used to predict and estimate loading on steam dryers, then the stress computation is improved, but the actual damage reduction is insufficient
Solution Approach 1:
The flow tripper is installed upstream at the standpipe opening to preemptively disrupt the flow and prevent the formation of shear layer instabilities before they can propagate downstream to the steam dryer. This preliminary action eliminates the need for downstream structural reinforcement or complex stress analysis modifications.
3Object-affected harmful factors
If a large cantilevered Helmholtz resonator is installed to mitigate acoustic loads, then the acoustic resonance is reduced, but the device complexity and installation difficulty increase
Solution Approach 1:
The flow tripper is a self-contained element that utilizes the kinetic energy of the flowing steam itself to create the disruption effect. No external power source, active control system, or complex support structure is required - the device serves itself by leveraging the existing flow to trip and disrupt the shear layer instability.
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 standpipe flow tripper effectively reduces acoustic loads on steam dryers and other equipment by disrupting shear layer instability and acoustic resonance, allowing for easier integration into existing nuclear power plants and facilitating power uprates by eliminating a major source of concern.
Implementation Method 1
disrupting shear layer instability and acoustic resonance
Implementation Method 2
acoustic resonance in nuclear reactors, particularly in boiling water reactors, causes damage to equipment
Data Source
AI summary
A system for reducing an acoustic load of a fluid flow includes a first pipe to carry the fluid flow; a standpipe connected to the first pipe at an opening in the first pipe; and a standpipe flow tripper provided in the standpipe. The flow tripper includes an edge extending through the opening into the flow on a downstream side of the opening. A method of reducing an acoustic load of a standing wave in a standpipe connected to a first pipe configured to carry a flow includes disrupting the flow in the first pipe at a downstream side of an opening in the first pipe to which the standpipe is connected.