Control Rod Position Detection Using Optical Reflection
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Solution Overview
Problem
Conventional position indicators in nuclear reactors, such as those using reed switches, face challenges in providing precise position information due to resolution limitations and the difficulty in withstanding harsh high-temperature environments, making it hard to accurately detect the position of control rods in small and medium-sized reactors.
Innovation Solution
An apparatus that includes a control rod driving shaft with marked position information, a mirror to reflect this information, and a detector system comprising an optical system, optical fiber, storage unit, and display unit to capture and display the reflected image, allowing for precise detection of the control rod position, even in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reed switch is used to detect control rod position, then the device can operate in harsh environments, but the position detection precision is insufficient due to resolution limitations
Solution Approach 1:
The patent replaces the mechanical/electromagnetic reed switch system with an optical detection system. A mirror attached to the control rod reflects light from an LED through optical fibers to a photodetector, enabling high-resolution position detection without the resolution limitations of reed switches while maintaining reliability in harsh nuclear reactor environments
Solution Approach 2:
The patent transitions from discrete positional detection (reed switch on/off states) to continuous positional detection by measuring the angular position of the mirror through optical reflection. This dimensional change from binary to continuous measurement enables precise position information extraction
2Measurement precision
If multiple reed switches are arranged to improve resolution, then position information precision may improve, but the device complexity and difficulty of withstanding high temperature increase
Solution Approach 1:
The patent replaces multiple temperature-sensitive reed switches with a single optical detection system using mirrors, LEDs, and optical fibers. This substitution eliminates the need for multiple high-temperature components while achieving superior resolution through optical angle measurement
Solution Approach 2:
The patent uses optical reflection (creating an optical copy/image of the mirror position) to transmit position information. The mirror's angular position is copied through light reflection to the photodetector, enabling precise position measurement without physically exposing multiple components to the harsh environment
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 apparatus achieves high-resolution, precise detection of control rod positions, enabling real-time monitoring and reducing the risk of abrasion damage, suitable for small and medium-sized nuclear reactors.
Implementation Method 1
a mirror (20) configured to reflect the position information (11)
Implementation Method 2
an optical fiber (32) connected to the optical system (31) and configured to transmit the image
Data Source
AI summary
An apparatus for detecting a position of a control rod includes a control rod driving shaft having an outer circumferential surface on which position information is marked, a mirror configured to reflect the position information, and a detector configured to detect a position of the control rod driving shaft from the position information reflected from the mirror, when the control rod driving shaft moves vertically.