Convex-Head Reactor Flow Distribution for Vortex Suppression
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Solution Overview
Problem
Existing reactor flow distribution devices in nuclear power plants suffer from complex structures and inadequate vortex suppression, leading to uneven coolant distribution and fluid pulsation in the reactor core, which causes power fluctuations.
Innovation Solution
A reactor vortex suppression and flow distribution device with a convex head and disturbance columns is installed in the reactor pressure vessel, featuring through holes and second coolant passages to guide coolant flow uniformly and suppress vortices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional flow distribution device is arranged below the reactor core, then the flow distribution uniformity is improved, but the device structure becomes complex and the vortex suppression effect is insufficient
Solution Approach 1:
The device segments the flow distribution function into two parts: the convex head with through-holes for initial flow distribution and the disturbance columns for vortex suppression. This segmentation allows each component to have a simplified structure while collectively achieving both flow uniformity and vortex suppression, resolving the contradiction between simplicity and effectiveness
Solution Approach 2:
The disturbance columns act as intermediary elements between the convex head and the reactor core lower support plate. These columns create controlled turbulence that suppresses vortex formation while the convex head distributes flow uniformly. The intermediary structure enables both functions without requiring a complex integrated device
2Speed
If the coolant flow channel changes sharply in the lower chamber, then the flow direction change is achieved, but vortex flow is generated and fluid pulsation occurs
Solution Approach 1:
The disturbance columns are positioned upstream in the lower chamber to preemptively suppress vortex formation before the coolant reaches the reactor core. By creating controlled turbulence early in the flow path, the device prevents the development of harmful large-scale vortices that would cause fluid pulsation and power fluctuations in the core
Solution Approach 2:
The convex head features a curved bottom surface that gradually guides the coolant flow from the annular downcomer into the lower chamber. This curved geometry reduces sharp flow direction changes and minimizes vortex generation at the inlet, addressing the harmful effects of abrupt flow transitions
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 device effectively suppresses vortex flow and redistributes coolant flow uniformly, reducing pulsation and ensuring even distribution within acceptable limits, meeting nuclear power plant design specifications.
Implementation Method 1
A plurality of disturbance columns are distributed at intervals between the convex head and the reactor core lower support plate, and the disturbance columns define a plurality of second coolant passages between the convex head and the reactor core lower support plate
Implementation Method 2
The generation of vortex flow can be effectively suppressed during the flow of coolant, thus effectively reducing the pulsation phenomenon of coolant fluid entering an inlet of the reactor core
Data Source
Figure 1~2
Figure 3
AI summary
A reactor votex suppression and flow distribution device, which is arranged in a reactor pressure vessel and comprises a reactor core lower support plate arranged at the bottom of a reactor core in the pressue vessel, and a convex head connected below the reactor core lower support plate. A plurality of through holes allowing a coolant to flow through are formed in the convex head. A first coolant passage is defined between the convex head and a lower head of the reactor pressure vessel. A plurality of spaced disturbance columns are distributed between the convex head and the reactor core lower support plate, the disturbance columns defining a plurality of second coolant passages between the convex head and the reactor core lower support plate. The reactor vortex suppression and flow distribution device does not use many parts and has a simple structure, the coolant sequentially flows through the first coolant passage, the through holes in the convex head, the second coolant passages and through holes in the reactor core lower support plate and then enters the reactor core, thereby effectively suppressing the generation of vortexes when the coolant fows, In addition, owing to coolant flow redistribution, an evenly-distributed flow can be formed at an inlet of the reactor core.