Multi-Solenoid Control Rod Position Indicator for Fault Tolerance
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Solution Overview
Problem
In small modular reactors, accurately measuring the position of control rods is challenging due to the densely packed internal structure, and damage to components of the position indicator can lead to inaccurate measurements, especially when one or more solenoids are damaged.
Innovation Solution
A simultaneous wound solenoid position indicator is placed within the reactor vessel, comprising a rod, a magnetic body, and a solenoid module with multiple solenoids wound around the rod, generating different inductance values based on the magnetic body's position, allowing the controller to derive the control rod's insertion degree even if some solenoids are damaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the position indicator is placed inside the reactor vessel in small modular reactors, then the reactor size can be reduced and compact design is achieved, but the measurement accuracy may be affected due to densely packed internal structure and potential component damage
Solution Approach 1:
The solenoid module is divided into multiple independent solenoids (first solenoid, second solenoid, third solenoid, fourth solenoid) that can independently generate inductance values. This segmentation allows the system to maintain measurement accuracy even if one or more solenoids are damaged, as the remaining functional solenoids can still provide valid position information.
Solution Approach 2:
Each solenoid in the solenoid module is configured to generate a specific inductance value corresponding to particular control rod positions (fully inserted, partially inserted, fully withdrawn). This local quality assignment ensures that each solenoid contributes uniquely to the overall position detection capability, maintaining measurement precision in the compact reactor environment.
2Reliability
If multiple solenoids are used in the position indicator, then reliability is improved by having backup measurement capabilities, but device complexity increases due to additional components
Solution Approach 1:
Multiple solenoids are merged into a single integrated solenoid module that surrounds the rod. This merging approach maintains reliability through redundancy while managing complexity by providing a unified structure with common mounting and electrical connections, rather than treating each solenoid as a completely separate component.
Solution Approach 2:
The solenoid module serves multiple functions: it acts as both the actuating mechanism for the control rod and the sensing mechanism for position detection through inductance changes. This multi-functionality reduces overall system complexity by eliminating the need for separate actuation and sensing systems.
3Volume of moving object
If solenoids are wound closely around the rod to save space, then compact design is achieved, but manufacturing precision becomes more difficult due to tight spacing requirements
Solution Approach 1:
The solenoids are arranged in a nested configuration around the rod, with each solenoid positioned at a specific radial distance. This nesting approach maximizes space utilization while maintaining manufacturable tolerances, as the concentric arrangement provides natural alignment references during assembly.
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 system ensures accurate measurement of control rod position by utilizing intact solenoids to generate independent inductance values, maintaining reactor control accuracy and compact reactor design despite potential solenoid damage, and operates reliably in high-temperature and high-pressure environments.
Implementation Method 1
a solenoid module that receives power from an external source and generates a magnetic field toward the magnetic body, wherein an inductance generated by the solenoid module changes due to interaction with a magnetic field of the magnetic body
Data Source
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AI summary
A simultaneous wound solenoid position indicator includes: a rod for raising or lowering a control rod such that a degree to which the control rod is inserted into a core is decreased or increased; a magnetic body; and a solenoid module that receives power from an external source and generates a magnetic field toward the magnetic body. An inductance generated by the solenoid module changes due to interaction with a magnetic field of the magnetic body as the control rod is driven up or down. The solenoid module includes a plurality of solenoids, and the plurality of solenoids are wound to surround the rod while being spaced at a predetermined distance radially outward from the rod.