Nuclear Reactor Fuel Assembly Support Grid with Hexagonal Coolant Flow
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Solution Overview
Problem
Existing support grids in nuclear reactors suffer from anisotropy, reduced strength and rigidity due to asymmetrical coolant flow openings, complex shapes leading to inefficient manufacturing, and insufficient web thickness, resulting in suboptimal structural integrity and increased labor costs.
Innovation Solution
A support grid with round coolant flow openings of two alternating diameters, evenly spaced around fuel element and central tube openings, enhancing rigidity and strength while maintainable by existing technologies without altering opening diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dumbbell-shaped coolant flow openings are used, then coolant flow is enabled, but anisotropy develops in the support grid structure reducing strength and rigidity
Solution Approach 1:
The patent applies asymmetry in reverse by using symmetric circular openings instead of asymmetric dumbbell-shaped openings. The circular openings are arranged in a symmetric pattern around the fuel element, eliminating the anisotropy caused by the dumbbell shape while maintaining coolant flow capability.
Solution Approach 2:
The patent changes the geometric parameter of the coolant flow openings from dumbbell-shaped to circular, and modifies the arrangement pattern to six openings positioned at vertices of an inscribed hexagon. This parameter change eliminates structural anisotropy and improves strength and rigidity.
2Productivity
If complex-shaped coolant flow openings are used, then coolant flow distribution is improved, but manufacturing complexity and labor input increase
Solution Approach 1:
The patent simplifies the geometric parameters of the coolant flow openings by using standard circular shapes instead of complex dumbbell shapes, making them easier to manufacture while maintaining effective coolant flow distribution through optimized positioning.
Solution Approach 2:
The circular openings serve multiple functions: they enable coolant flow, maintain structural symmetry, and simplify manufacturing. The standardized circular shape can be produced using conventional drilling or punching techniques, reducing manufacturing complexity.
3Productivity
If small web thickness between openings is used, then more openings can be accommodated, but strength and rigidity of the grid are reduced
Solution Approach 1:
The patent optimizes the spatial arrangement of openings by positioning six coolant flow openings at the vertices of an inscribed hexagon around each fuel element opening. This two-dimensional optimized layout achieves better web thickness distribution and structural balance compared to linear or asymmetric arrangements.
Solution Approach 2:
The patent modifies the geometric parameters of the opening arrangement by using a hexagonal pattern with specific spacing, which optimizes the web thickness between openings while accommodating the required number of coolant flow openings.
Data Source
Figure 1~2
AI summary
The invention relates to nuclear engineering, in particular to the fuel assembly elements used substantially for the WCPR-400 and WCPR-100 reactors. The inventive support grid for the fuel assembly of a nuclear reactor is designed in the form of a plate which is provided with round openings for a heat carrier flow, round openings for mounting the fuel elements, a central tube and supporting tubes or guiding channels, wherein the openings for the heat carrier flow are uniformly disposed by six around each of the openings for mounting the fuel elements, the central tube and the supporting tubes or guiding channels. The openings for the heat carrier flow have two different diameters and are disposed around each of said openings so that the openings of different diameters alternate with each other. The invention makes it possible to increase the rigidity, strength and manufacturability of the grid.