Extended Control Rod Guide Assembly for Nuclear Reactor Wear Reduction
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Solution Overview
Problem
Conventional nuclear reactor designs experience aggressive guide card wear, leading to increased maintenance costs and radioactive waste generation, necessitating frequent replacements that are costly and inefficient.
Innovation Solution
An extended control rod guide assembly is introduced, supported at the intermediate coupling and extending axially into both the lower and upper guide tube sections, providing continuous or discrete support for control rods, thereby compensating for wear without adding significant friction and extending the guide tube's life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional guide cards are used in control rod guide tubes, then the guide tube structure is simple, but aggressive wear occurs leading to frequent replacements and increased maintenance costs
Solution Approach 1:
The guide tube is divided into multiple sections with guide cards positioned at specific intervals. The intermediate coupling allows segmentation of the guide tube into upper and lower sections that can be independently accessed. This segmentation enables replacement of only worn guide cards rather than the entire guide tube, extending service life while maintaining structural simplicity.
Solution Approach 2:
An intermediate coupling is introduced as a mediator component between the upper and lower guide tube sections. This intermediate coupling provides a connection point that allows for the insertion and replacement of guide cards without requiring complete disassembly of the guide tube. The intermediate coupling thus enables maintenance access while preserving the overall guide tube structure.
2Reliability
If guide cards are frequently replaced to compensate for wear, then control rod operation reliability is maintained, but maintenance costs and radioactive waste generation increase
Solution Approach 1:
The guide cards are pre-positioned at specific locations within the guide tube sections, and the intermediate coupling is designed to facilitate easy access to these pre-positioned guide cards. This preliminary arrangement allows for rapid replacement of worn guide cards during maintenance outages, minimizing the time required for maintenance activities while ensuring control rod operation reliability is maintained.
3Duration of action of stationary object
If the guide tube is made more robust to reduce wear, then guide tube life is extended, but friction on control rods increases affecting operation
Solution Approach 1:
Instead of making the entire guide tube more robust, the invention applies wear compensation locally through replaceable guide cards positioned at specific locations where wear occurs. The guide cards can be replaced when worn, extending guide tube life without requiring changes to the main guide tube structure that would increase friction. This local quality approach maintains ease of control rod operation while extending component life.
Data Source
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AI summary
A nuclear reactor having an upper internals control rod assembly guide tube formed from upper and lower sections that are connected along a central axial region of the guide tube at an intermediate coupling. An extended control rod axial support is provided for at least some of the control rods over a finite distance within at least one of the interiors of the lower guide tube section or the upper guide tube section.