Reactor Internals Flow Hole Layout for Uniform Coolant Outlet Flow
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Solution Overview
Problem
Uneven coolant flow distribution at the core outlet of nuclear reactors leads to large cross flows, complicating the flow field and causing significant abrasion between the guide cylinder assembly and control rod, which shortens their service life and affects reactor safety and economy.
Innovation Solution
The design of reactor internals with specific flow hole configurations in the core upper plate and supporting column assembly, including circular and square flow holes, along with iterative calculations to achieve uniform coolant distribution, reduces cross flows and abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional reactor internals design is used, then the structure is simple and easy to manufacture, but the coolant flow distribution at core outlet is uneven, causing large cross flows and flow-induced vibrations
Solution Approach 1:
The core upper plate is segmented into multiple flow holes with different geometries (circular, square, rectangular) and different sizes. Each flow hole serves as an independent flow channel with tailored characteristics to distribute coolant uniformly across the core outlet, thereby reducing cross flows and flow-induced vibrations while maintaining structural simplicity
Solution Approach 2:
Different regions of the core upper plate are assigned different flow hole types and sizes according to local flow requirements. The flow hole configuration is optimized locally to achieve uniform coolant distribution across the entire core outlet, addressing specific flow imbalances in different zones without requiring complex overall structural changes
2Reliability
If flow holes with different geometries and sizes are used, then uniform coolant flow distribution is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention employs flow holes with varying geometric parameters (circular, square, rectangular shapes and different sizes) to optimize coolant flow distribution. By changing the geometric parameters of flow holes rather than the overall structure, uniform flow distribution is achieved while keeping manufacturing within feasible precision ranges for standard fabrication processes
3Duration of action of stationary object
If uniform coolant flow distribution at core outlet is achieved, then cross flows are reduced and abrasion between guide cylinder assembly and control rod is relieved, but the design complexity increases
Solution Approach 1:
The core upper plate is divided into multiple flow holes with different geometries and sizes, creating independent flow paths that collectively achieve uniform coolant distribution. This segmentation approach reduces cross flows and flow-induced vibrations, thereby extending the service life of the guide cylinder assembly and control rod through a relatively simple configurational design
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 solution effectively balances coolant flow at the core outlet, reducing cross flows and abrasion, thereby improving the safety and economy of the nuclear reactor.
Implementation Method 1
a plurality of flow holes through which fluids are enabled to pass are provided in the core upper plate
Data Source
Figure 1
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AI summary
Reactor internals of a nuclear reactor, a nuclear reactor and a method for designing reactor internals. The reactor internals (30) comprise a core upper plate (1), a guide cylinder assembly (2), and a supporting column assembly (4). A plurality of flow holes (11) through which fluids are enabled to pass are provided in the core upper plate (1). The plurality of flow holes (11) comprise a first circular flow hole (111), a second circular flow hole (112) and a square flow hole (113). The guide cylinder assembly (2) is arranged above the square flow hole (113). The supporting column assembly (4) is installed above the first circular flow hole (111). In this way, the cross flow between flow channels can be effectively reduced, the abrasion between a control rod (3) and the guide cylinder assembly (2) is relieved, and the economy and safety of the nuclear reactor (100) are improved.