Continuous Control Rod Guide Frame for Nuclear Reactors
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Solution Overview
Problem
The existing control rod guide frames with spaced apart guide plates in nuclear reactors are prone to rod bowing, which can cause insertion failures, limit shutdown speed, and pose safety risks due to potential blockages and vibrations, affecting reactivity control and material fatigue.
Innovation Solution
A continuous control rod guide frame comprising a self-supporting stack of columnar elements with a central passage of constant cross-section, providing continuous guidance and support to prevent bowing and vibrations, allowing for higher driving forces and faster reactor shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If spaced apart guide plates are used in the control rod guide frame, then weight and material cost are reduced, but rod bowing occurs leading to insertion failures and safety risks
Solution Approach 1:
The guide frame is segmented into multiple guide plates spaced apart vertically, each providing localized guidance. This segmentation reduces overall material usage and weight while maintaining guidance function at critical intervals along the control rod path.
Solution Approach 2:
The guide plates utilize composite structural design with optimized material distribution, combining high-strength materials in critical guidance regions with lighter materials in non-critical areas, achieving weight reduction without compromising guidance reliability.
2Ease of manufacture
If spaced apart guide plates are used, then manufacturing simplicity is improved, but rod vibrations increase causing material fatigue
Solution Approach 1:
The guide frame is divided into discrete guide plates that are simpler to manufacture individually than a continuous structure. Each plate can be fabricated and assembled independently, simplifying manufacturing while the spaced configuration provides sufficient vibration damping for fatigue resistance.
3Reliability
If continuous guidance is provided to suppress rod bowing, then insertion reliability is improved, but device complexity increases
Solution Approach 1:
Rather than implementing a complex continuous guidance structure, the system uses multiple discrete guide plates segmented vertically. This segmentation provides sufficient guidance to suppress bowing and improve insertion reliability while keeping the overall structure simpler through modular assembly.
Data Source
AI summary
A control rod guide frame comprises a self supporting stack of two or more columnar elements defining a central passage. The columnar elements may include mating features that mate at abutments between adjacent columnar elements of the stack. The control rod guide frame is suitably used in conjunction with a control rod drive mechanism (CRDM) operatively connected with at least one control rod, and a nuclear reactor core, in which the CRDM moves the at least one control rod into and out of the nuclear reactor core under guidance of the control rod guide frame. In another embodiment, a control rod guide frame comprises a stack of two or more columnar elements defining a central passage having a constant cross-section as a function of position along the central passage. In another embodiment, a control rod guide frame comprises an extruded columnar element providing continuous control rod guidance.