Digital Rod Position Measurement Device for Nuclear Reactors

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Solution Overview

Problem

Traditional rod control systems in nuclear power plants lack a feedback mechanism to verify the execution of control rod cluster commands, leading to the need for complex and inaccurate rod position measurement systems.

Innovation Solution

A full-digital control rod position measurement device and method that transforms analog signal processing into digital processing, using an excitation power supply and a universal signal processor to collect and process signals from rod position detectors, compensating for magnetic field variations and improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional analog signal processing is used in rod position measurement systems, then the system structure is complex and requires multiple analog components, but the measurement accuracy is limited and operation reliability is reduced

Engineering Contradiction:
Improverod position measurement accuracyVSAvoidsignal processing circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the traditional analog signal processing system with a digital signal processing system. The analog-to-digital converter transforms analog signals from measurement coils into digital signals, which are then processed by a microprocessor or digital signal processor. This substitution eliminates the need for complex analog filtering, amplification, and conditioning circuits, thereby reducing device complexity while improving measurement accuracy through digital algorithms that can compensate for magnetic field variations and temperature effects.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the signal processing domain from analog to digital by introducing an analog-to-digital conversion stage. This parameter change enables the use of digital signal processing techniques including Fourier transforms, digital filtering, and algorithmic compensation for environmental variations. The digital domain allows for more precise control and processing of measurement signals, improving accuracy without requiring additional analog components.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional rod position measurement systems are implemented, then the primary excitation circuit and secondary signal processing circuit are complex, but the operation reliability is reduced and measurement accuracy is limited

Engineering Contradiction:
Improveoperation reliabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex analog excitation circuits and signal processing circuits with a simplified digital system. A single microprocessor or digital signal processor performs functions that traditionally required multiple analog circuits including excitation generation, signal amplification, filtering, and processing. This consolidation reduces the number of components, minimizing failure points and improving operation reliability while reducing overall circuit complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent merges multiple separate circuit functions into a single integrated digital processing unit. The excitation signal generation, measurement signal acquisition, analog-to-digital conversion, and signal processing are combined into one unified digital system controlled by a microprocessor. This merging eliminates the need for separate analog excitation circuits and secondary processing circuits, reducing complexity and improving reliability through fewer interconnections and components.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If complex rod position measurement systems are used, then more components are required for signal processing, but the time required for performance appraisal and refueling outages increases

Engineering Contradiction:
Improverefueling outage efficiencyVSAvoidperformance appraisal time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent replaces complex analog signal processing equipment with a compact digital processing system that can be quickly installed and calibrated. The digital system requires fewer components and connections, reducing the time needed for installation during refueling outages. Additionally, the digital processing algorithms can rapidly analyze measurement data and complete performance appraisals faster than traditional analog systems, directly improving productivity and reducing outage time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution simplifies the primary excitation circuit and secondary signal processing, enhances operation reliability, and improves measurement accuracy, reducing the time required for performance appraisal and refueling outages.

Implementation Method 1

a primary electromagnetic coil arranged to generate a time varying magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a secondary electromagnetic coil arranged to detect the time varying magnetic field as affected, directly or indirectly, by the object

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3706139B1Fully-digital rod position measurement device and method therefor
Publication Date: 2025.02.12 CNNC NUCLEAR POWER OPERATION MANAGEMENT CO LTD
  • EP3706139B1 patent drawingFigure 1
  • EP3706139B1 patent drawingFigure 2
  • EP3706139B1 patent drawingFigure 3~4

AI summary

A full-digital control rod position measurement device and a method thereof; the full-digital rod position measurement device transforms the core process of rod position measurement that is normally processed by an analog circuit or analog-to-digital mixed circuit into a digital processing; the full-digital rod position measurement device comprises an excitation power supply, an integrated interface board and a universal signal processor; the universal signal processor processes the output signals of detectors according to the preset numerical processing algorithm and outputs the Gray code rod position signals; the full-digital rod position measurement device and method disclosed by the present invention can effectively reduce the complexity of the primary excitation circuit and the secondary measurement signal processing circuit of the detectors, and improve the operation reliability and measurement accuracy of the rod position processing equipment.