Instrumentation Guide Tube Vibration Suppression via Differential Pressure
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Solution Overview
Problem
The top insertion method for instrumentation guide tubes in pressurized water reactors causes flow vibration due to coolant water flow, leading to potential wear and damage from collisions with reactor structures.
Innovation Solution
A structure that includes a guide tube with a head nozzle and pressure adjustment holes to press the instrumentation guide tube against the inner surface, utilizing differential pressure to suppress flow vibration, and features like inverted truncated cone shapes and corrugated designs to reduce turbulence and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the top insertion method is used to insert the instrumentation guide tube from top to bottom, then the insertion process can be simplified and productivity improved, but flow vibration is excited by coolant flow causing wear and damage
Solution Approach 1:
The invention converts the harmful coolant flow that causes vibration into a beneficial force by using the flow to generate differential pressure. The differential pressure between the coolant inside and outside the guide tube presses the guide tube against the inner circumferential surface, stabilizing it and preventing vibration-induced wear while maintaining the simplified top insertion method.
Solution Approach 2:
The invention applies hydraulic principles by utilizing coolant pressure differential to stabilize the instrumentation guide tube. The lower hole allows coolant to enter the guide tube, creating a pressure difference between the interior and exterior of the guide tube, which generates a pressing force that constrains the guide tube against the inner circumferential surface and prevents flow vibration.
2Stability of the object's composition
If the instrumentation guide tube is inserted through the hollow upper core support column, then the structural integration is improved, but the guide tube is exposed to coolant flow that causes vibration and wear
Solution Approach 1:
The invention converts the harmful coolant flow into a beneficial stabilizing force. The coolant flow that would normally cause vibration is redirected to create differential pressure through the lower hole, which then presses the guide tube against the inner circumferential surface of the hollow upper core support column, eliminating the harmful vibration effect while maintaining structural integration.
Solution Approach 2:
The lower hole acts as an intermediary element that mediates between the coolant flow and the guide tube. It allows the coolant to enter the guide tube and create a pressure differential, which then serves as the mediating force that presses the guide tube against the inner circumferential surface, preventing direct contact with turbulent coolant flow.
3Reliability
If the instrumentation guide tube is pressed against the inner circumferential surface by differential pressure, then flow vibration is suppressed, but the structure becomes more complex
Solution Approach 1:
The invention segments the guide tube structure by adding a lower hole as a separate functional element. This segmentation allows the guide tube to have both its insertion function and its vibration suppression function, with the lower hole serving as the interface for differential pressure application. The segmentation is minimal and does not significantly increase overall structural complexity.
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
Effectively suppresses flow vibration, preventing wear and ensuring smooth insertion and operation of instrumentation guide tubes by leveraging differential pressure and optimized nozzle designs.
Implementation Method 1
the instrumentation guide tube is pressed against an inner circumferential surface of the guide tube, by a differential pressure between coolant inside and outside the lower hole
Data Source
AI summary
An upper hole 37A and a lower hole 37B are provided at two positions, namely, upper and lower portions, of a side surface of a guide tube 27, and a thimble tube 22 is pressed against an inner circumferential surface of the guide tube 27, by a differential pressure between coolant inside and outside the upper hole 37A and the lower hole 37B. It is preferable that an upper pressure adjustment hole and a lower pressure adjustment hole are provided at two positions, namely, upper and lower portions, of a side surface of an upper core support column 21, and a coolant flowing into the guide tube from an upper end of the guide tube flows out to the outside from inside the guide tube through a gap between the thimble tube and the upper hole, and also flows out to the outside from inside the upper core support column through the upper pressure adjustment hole, and a coolant flowing into the guide tube from a lower end of the guide tube flows out to the outside from inside the guide tube through a gap between the thimble tube and the lower hole, and also flows out to the outside from inside the upper core support column through the lower pressure adjustment hole.