Dual Emitter Neutron Detector Calibration via Rhodium-Vanadium Segmentation
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Solution Overview
Problem
There is no known prior art that provides for the calibration of a long-lived, low neutron absorption cross-section self-powered in-core neutron detector during the operation of a nuclear reactor by a high neutron absorption cross-section self-powered in-core neutron detector, which limits the extended use of the long-lived detector after the short-lived detector has depleted.
Innovation Solution
A method and apparatus for calibrating a first self-powered neutron detector with a second self-powered neutron detector, where the emitter of the first detector comprises vanadium and the emitter of the second detector comprises rhodium, allowing the neutron flux to be monitored with the rhodium detector until it is highly depleted, and then switching to the calibrated vanadium detector for continued monitoring, enabling the use of the calibrated vanadium detector after the rhodium detector's sensitivity has been reduced by about 68% to 80%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high neutron absorption cross-section emitter (rhodium) is used in a self-powered in-core neutron detector, then the detector provides high sensitivity and accurate neutron flux measurement, but the emitter depletes quickly limiting the detector's operational lifetime
Solution Approach 1:
The detector system is segmented into two distinct emitter types: rhodium for high-precision measurement during early operation, and vanadium for long-duration monitoring after rhodium depletion. This segmentation allows each emitter to optimize its function within its operational window, resolving the contradiction between measurement precision and operational lifetime.
Solution Approach 2:
The system changes the emitter material parameter from rhodium to vanadium as operation progresses. This parameter change allows the detector to maintain high measurement precision initially with rhodium, then transition to a different material property (lower absorption cross-section but longer half-life) to extend operational lifetime when the first emitter depletes.
2Duration of action of moving object
If a long-lived low neutron absorption cross-section emitter (vanadium) is used in a self-powered in-core neutron detector, then the detector maintains operational lifetime, but the detector signal becomes weak reducing measurement sensitivity
Solution Approach 1:
The rhodium detector is deployed first to perform preliminary high-precision calibration and measurement during the early high-sensitivity phase. This preliminary action establishes a reference that allows the subsequent vanadium detector to be calibrated and maintain measurement accuracy despite its lower inherent sensitivity.
Solution Approach 2:
The rhodium detector serves as an intermediary that transfers calibration information to the vanadium detector. By using the rhodium detector's high-precision measurements to calibrate the vanadium detector, the system overcomes the vanadium detector's inherent weakness in sensitivity, allowing it to provide accurate measurements throughout its extended operational lifetime.
3Device complexity
If a single emitter type is used in a self-powered in-core neutron detector, then the detector structure is simple, but the detector cannot maintain accurate measurement over extended periods due to emitter depletion
Solution Approach 1:
The detector system achieves multi-functionality by incorporating two emitter types that serve different operational phases. The rhodium emitter handles early high-precision calibration, while the vanadium emitter handles long-term monitoring. This universal design allows a single detector system to perform both calibration and extended measurement functions, maintaining reliability without requiring multiple separate detectors.
4Duration of action of moving object
If the detector operates until the emitter is highly depleted, then the full operational lifetime is utilized, but the measurement accuracy deteriorates due to emitter depletion effects
Solution Approach 1:
The rhodium emitter functions as a disposable short-lived component that provides high-precision calibration during its active phase. Once depleted, it is replaced by the vanadium emitter, which provides long-term monitoring. This approach allows the system to utilize the full operational lifetime by transitioning from a short-lived high-precision component to a long-lived monitoring component.
Solution Approach 2:
The rhodium detector performs preliminary calibration and measurement during its active phase before depletion significantly impacts accuracy. This preliminary action captures the high-precision data needed for calibration, after which the system transitions to the vanadium detector that maintains acceptable measurement accuracy throughout its extended operational lifetime.
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 extends the useful lifetime of the neutron flux monitoring by allowing the calibrated vanadium detector to take over when the rhodium detector's sensitivity is significantly depleted, providing accurate and continuous neutron flux measurements over multiple reactor cycles.
Implementation Method 1
the signal from the detector is reported to be directly proportional to the rate of absorption of neutrons by the detector
Implementation Method 2
emitters emit electrons as a result of neutron capture by nuclei of emitter atoms, followed by beta decay of the resulting activated nuclei
Implementation Method 3
emitters emit electrons as a result of neutron capture by nuclei of emitter atoms, followed by beta decay of the resulting activated nuclei
Implementation Method 4
the electrical properties of the insulator remain substantially unchanged when exposed to intense radiation fields for extended periods of time
Data Source
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AI summary
The present invention provides a method and an apparatus for calibrating a first self-powered neutron detector for long term use in a nuclear reactor core with a second self-powered neutron detector, where the emitter material of the second self-powered neutron detector has a neutron absorption cross-section that is greater than the neutron absorption cross-section of the first emitter material for the first self-powered neutron detector.