Nuclear Reactor Core Barrel Straightener Member
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In pressurized water reactors, the coolant flow in the lower plenum is not uniform, leading to the formation of vortices and reduced heat exchange efficiency due to collisions with structural elements, making it difficult to achieve consistent coolant distribution across the core.
Innovation Solution
A nuclear reactor design incorporating a straightener member with a ring-shaped straightening ring and spokes supported by columns, along with an auxiliary ring and vortex elimination members, which disperses and straightens the coolant flow in the radial and circumferential directions, preventing the formation of large vortices and ensuring uniform coolant distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coolant flows through the downcomer portion and lower plenum in conventional reactor design, then the coolant can be supplied to the core, but the coolant flow becomes non-uniform and vortices are formed due to collisions with structural elements
Solution Approach 1:
A flow straightener is introduced as an intermediary component in the lower plenum between the downcomer portion and the core. This flow straightener acts as a mediator that redirects and uniformizes the coolant flow, preventing direct collision with structural elements like the radial key and instrumentation guide tubes, thereby eliminating vortex formation while ensuring reliable coolant supply to the core
Solution Approach 2:
The lower plenum flow path is segmented into distinct regions by the flow straightener, which divides the incoming coolant flow from the downcomer and redistributes it uniformly across the core inlet area. This segmentation prevents concentrated flow paths that would otherwise collide with structural elements and generate vortices
2Loss of energy
If a connection plate is added to straighten coolant flow in the lower plenum, then pressure drop is reduced and flow stability is improved, but large vortices are still generated after passing through the connection plate
Solution Approach 1:
The flow straightener serves as an intermediary that more effectively uniformizes flow compared to a simple connection plate. It is specifically designed with flow-guiding surfaces that prevent the formation of large vortices downstream, while still reducing pressure drop by minimizing flow resistance and promoting smooth, uniform flow distribution to the core
Solution Approach 2:
The flow straightener modifies the flow parameters (velocity distribution, flow direction) in the lower plenum by redirecting coolant away from structural elements. This parameter change prevents the formation of high-velocity concentrated streams that would collide with structures and generate vortices, thereby reducing both pressure drop and harmful flow patterns
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 design enhances heat exchange efficiency by ensuring uniform coolant flow across the core, reducing pressure drop and stabilizing the coolant flow, thereby improving the overall performance of the nuclear reactor.
Implementation Method 1
A nuclear reactor design incorporating a straightener member with a ring-shaped straightening ring and spokes supported by columns, along with an auxiliary ring and vortex elimination members, which disperses and straightens the coolant flow in the radial and circumferential directions
Implementation Method 2
The coolant flowing into the core absorbs thermal energy generated by fuel assemblies that form the core, thereby cooling the fuel assemblies
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a nuclear reactor, a core barrel (46) is disposed in a reactor vessel (41) having an inlet nozzle (44) and an outlet nozzle (45), a core (53) is disposed in the core barrel (46), a lower plenum (58) is partitioned by the reactor vessel (41) and a bottom portion of the core barrel (46), and a downcomer portion (59) is partitioned by the reactor vessel (41) and a side wall of the core barrel (46). The lower plenum (58) includes a straightening member (61) formed of an upper ring (65) and a lower ring (69) in a ring shape, and a plurality of spokes (64 and 68) radially arranged inside the rings (65 and 69), respectively. Heat exchange efficiency is enhanced by uniformly supplying coolant introduced into a pressure vessel to the core from the lower plenum in a radial direction and a circumferential direction.