Nuclear Reactor Fuel Assembly Nozzle Detachable Locking Mechanism
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Solution Overview
Problem
The existing fuel assembly structures for nuclear reactors are complex and time-consuming to assemble and disassemble due to the need for multiple removable parts and welds, which complicates manufacturability and increases downtime during refueling.
Innovation Solution
A fuel assembly design featuring guide channels with detachable nozzles secured using a locking device with spring-loaded screws and single-component bushes, eliminating the need for removable components and welds, allowing simultaneous securing of nozzles and reducing the number of fastening elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fastening methods with multiple removable parts and welds are used, then reliable connection of nozzles to guide channels is achieved, but manufacturing complexity and assembly time increase significantly
Solution Approach 1:
The fastening structure is segmented into a locking device with multiple independent locking elements (3-5 elements per nozzle), each capable of independently engaging with the guide channel. This segmentation allows for simplified individual elements while maintaining collective reliability through redundancy.
Solution Approach 2:
Multiple fastening functions are merged into a single integrated locking device that simultaneously performs positioning, locking, and sealing functions. The locking device combines several locking elements and fastening means into one unified component structure, reducing the total number of separate parts.
2Reliability
If multiple removable parts and welds are used for fastening, then secure connection is achieved, but manufacturing time and work content increase
Solution Approach 1:
The locking elements are pre-configured in the locking device with predetermined engagement geometries that automatically align with the guide channel features during assembly. The spring-loaded fastening means is pre-tensioned to provide immediate securing force upon engagement, eliminating the need for post-assembly adjustments or welding operations.
Solution Approach 2:
Traditional welding operations are replaced with a purely mechanical locking system using spring-loaded fastening means and geometric interlocking elements. This substitution eliminates thermal processes and complex welding procedures, allowing for faster assembly and disassembly operations.
3Reliability
If traditional fastening methods with multiple components are used, then reliable nozzle securing is achieved, but disassembly time during refueling increases
Solution Approach 1:
The fastening system incorporates dynamic elements including spring-loaded fastening means that can be quickly activated or deactivated. The locking elements are designed to transition smoothly between locked and unlocked states, enabling rapid nozzle removal and installation during refueling operations without compromising securing reliability when locked.
Solution Approach 2:
The fastening function is extracted from the nozzle body itself and placed in a separate, dedicated locking device. This extraction allows the nozzle to be a simpler component while the locking device handles all fastening operations, making the disassembly process more straightforward and faster during refueling.
4Reliability
If multiple separate fastening elements are used, then reliable connection is achieved, but the number of operations and parts increases
Solution Approach 1:
Multiple locking functions are merged into a single integrated locking device that houses 3-5 locking elements within one structure. The fastening means, locking elements, and positioning features are combined into a unified assembly that acts as one functional unit, reducing the bill of materials and assembly steps.
Solution Approach 2:
The locking device is designed as a universal component that can be applied to multiple nozzles and guide channels with standardized dimensions. The same locking device structure serves multiple functions: positioning the nozzle, securing it against axial and radial forces, and providing a standardized interface for rapid attachment and detachment.
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
This design simplifies and accelerates the manufacturing and repair processes by reducing the time required for mounting and dismounting nozzles, enhancing manufacturability, and minimizing reactor downtime during refueling.
Implementation Method 1
The fastening means for fastening the locking device to the bearing plate is formed as springloaded screws
Data Source
AI summary
The present disclosure provides for designs of fuel assemblies and may be used in pressurized water reactors. In some embodiments, a nuclear reactor fuel assembly may comprise a bundle of fuel rods, guide channels, two nozzles, one of which has a bearing plate with openings, elements for the detachable connection of the nozzles to the guide channels, a detachable connection locking device and a locking device fasteners, the elements for the detachable connection of the nozzles to the guide channels have a cross-section size greater than the size of the openings in the nozzle bearing plate. The present disclosure may provide greater ease in loading and unloading, reduce the time required for the mounting and removal of the nozzles during manufacture of the fuel assembly, and reduce the length of the reactor refueling process.