Reactivity Calculation Using Neutron Detector Statistical Checks
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Solution Overview
Problem
Current methods for measuring bank worth of control rods in nuclear reactors, particularly in the low power physics testing range, are inefficient and can disrupt the safety functions of neutron instrumentation systems, leading to inaccurate reactivity calculations due to step changes in detector signals during mode transitions.
Innovation Solution
A method and system that involve receiving neutron detector responses, performing statistical checks to determine acceptability, and using either prior or newly calculated delayed neutron concentrations to accurately calculate reactivity, thereby eliminating the impact of step changes in detector signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bank worth measurement methods (boron dilution or rod swap) are used, then measurement accuracy is maintained, but measurement time is excessively long (24 hours or more)
Solution Approach 1:
The patent changes the measurement parameters by using dynamic rod worth measurement techniques that allow faster rod movement speeds and different detection parameters. The system processes data at higher speeds using advanced algorithms that can handle the dynamic nature of faster measurements, thereby reducing measurement time while maintaining accuracy.
Solution Approach 2:
The patent replaces traditional mechanical measurement procedures with digital signal processing and computer-based analysis. The Advanced Digital Reactivity Computer (ADRC) substitutes manual calculation and traditional reactivity computer methods with automated digital processing, enabling faster data acquisition and analysis without sacrificing measurement precision.
2Productivity
If power range detectors are used for DRWM, then measurement speed is improved, but safety function is compromised due to detector channel removal
Solution Approach 1:
The patent makes the detector system multi-functional by enabling it to simultaneously perform both safety monitoring and reactivity measurement functions. The system can operate in different modes depending on the operational phase, allowing the same detector infrastructure to serve dual purposes without compromising safety functions.
Solution Approach 2:
The patent introduces an intermediary processing system that separates the safety function from the measurement function. The ADRC acts as an intermediary that processes measurement data without interfering with the safety-critical detector channels, allowing fast measurements while preserving safety monitoring capabilities.
3Measurement precision
If fission chamber detectors operate in pulse mode, then detection sensitivity is improved, but signal stability deteriorates due to mode transition step changes
Solution Approach 1:
The patent implements feedback mechanisms that monitor detector operating conditions and automatically adjust parameters to maintain signal stability. The system detects mode transition events and applies correction factors or switches detection modes appropriately, preventing step changes from affecting measurement accuracy while preserving detection sensitivity.
Solution Approach 2:
The patent makes the detection system dynamic by allowing it to adapt its operating mode based on real-time conditions. The system can transition between pulse mode and other detection modes as needed, and the data processing algorithms dynamically adjust to account for mode transitions, thereby maintaining both sensitivity and stability.
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
This approach allows for precise reactivity calculations during low power physics testing, maintaining safety functions and reducing measurement time, using a single neutron detector rather than multiple detectors.
Implementation Method 1
neutron detector structured to detect neutron flux produced in the reactor core
Data Source
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Figure 2B
AI summary
A method of determining reactivity of a nuclear reactor by a reactivity computer may include receiving a neutron detector response for a discrete period of time, performing a statistical check on the neutron detector response, determining if the neutron detector response is acceptable based on the statistical check, and calculating reactivity using a prior delayed neutron concentration if the neutron detector response is not acceptable and using a newly calculated delayed neutron concentration if the neutron detector response is acceptable.