Nuclear Fuel Spacer Grid with Angled Spring Tabs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing spacer grids in nuclear reactor fuel bundles allow movement of fuel rods during reactor operation and shipping, causing coolant flow inhibition and structural damage, and inhibit coolant flow between channel walls and peripheral fuel rods, leading to power losses and potential damage.
Innovation Solution
A spacer grid design featuring interstitial dividers and a perimeter band with spring tabs that extend at an angle to contact the channel walls, maintaining fuel rods in a centered position, reducing movement and structural damage, and assisting in coolant stripping from channel walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gap exists between the perimeter band and channel walls to facilitate fuel rod insertion, then ease of operation is improved, but fuel rod stability deteriorates causing movement and damage
Solution Approach 1:
The perimeter band incorporates spring tabs that function as flexible elements, allowing the band to be compressed during fuel rod insertion while maintaining stable contact with channel walls during operation, thus resolving the contradiction between ease of insertion and operational stability
Solution Approach 2:
The spring tabs transition the perimeter band from a static rigid structure to a dynamic flexible structure that adapts to different operational states: compressed during insertion and extended during stable operation, simultaneously achieving ease of operation and reliability
2Ease of operation
If the perimeter band is positioned away from channel walls to allow fuel rod movement, then ease of operation is improved, but coolant flow inhibition worsens causing power losses
Solution Approach 1:
The spring tabs create a flexible perimeter band that can adapt its position, allowing fuel rods to be adjusted during insertion while maintaining optimal positioning during operation to prevent coolant flow inhibition and maximize power generation
3Strength
If the perimeter band is rigid to maintain structural integrity, then strength is improved, but coolant flow between channel walls and fuel rods is inhibited
Solution Approach 1:
The spring tabs transform the rigid perimeter band into a flexible structure that maintains structural integrity through elastic deformation while allowing sufficient clearance for optimal coolant flow between channel walls and fuel rods, thus resolving the contradiction between strength and productivity
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 spacer grid design enhances fuel bundle performance by maintaining fuel rod alignment, reducing structural and fretting damage, and improving coolant flow, thereby maximizing power generation and preventing damage during shipping and operation.
Implementation Method 1
The spring tabs extend from the edge at an angle away from the dividers such that a distal end of each spring tab will contact an interior surface of a respective one of a plurality of walls of a channel
Data Source
AI summary
In various embodiments, a spacer grid for a nuclear reactor fuel bundle is provided. The grid includes a plurality of interstitial dividers that form an array of cells. Each cell is structured to retain a respective one of a plurality of fuel rods to thereby form an array of equally spaced fuel rods. The grid additionally includes a perimeter band that peripherally surrounds the dividers and is connected to opposing ends of each divider. The perimeter band includes a plurality of spring tabs formed along and extending from an edge of the perimeter band. The spring tabs extend from the edge at an angle away from the dividers such that a distal end of each spring tab will contact an interior surface of a respective one of a plurality of walls of a channel in which the arrayed fuel rods can be inserted to form the fuel bundle.