Fixed SiC Schottky In-Core Detector Array for Axial-Radial Gamma Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nuclear reactor measurement systems face challenges in accurately measuring localized gamma radiation for fuel performance and power distribution due to limited sensor density and averaging, which complicates reactor design verification and operation.
Innovation Solution
A gamma radiation detector assembly using SiC Schottky diodes with enhanced sensitivity is designed with high axial and radial sensor density, allowing for precise measurements by adjusting the distance between electron donor layers and Schottky contacts to detect specific gamma energies, and is housed in an elongate container for optimal placement within a reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of radiation sensors are used in fixed axial and radial locations (FID system), then device complexity is reduced, but measurement precision deteriorates due to averaging and limited sensor density
Solution Approach 1:
The detector is segmented into multiple discrete sensor elements (e.g., 8 radial segments × 12 axial segments = 96 measurement points) within a single fixed in-core detector unit. This segmentation allows the detector to provide high-resolution spatial mapping of gamma radiation without requiring multiple separate sensors or complex movable systems, thereby maintaining device simplicity while achieving high measurement precision.
2Measurement precision
If sensor density is increased to improve localized measurement, then measurement precision improves, but device complexity increases due to more sensors and associated components
Solution Approach 1:
Multiple sensor elements are merged into a single integrated fixed in-core detector unit that can be inserted into one fuel assembly. The sensor elements share common structural support, housing, and insertion mechanisms, combining the functionality of what would otherwise require multiple separate sensors or a complex movable system. This merging achieves high sensor density without proportionally increasing device complexity.
3Ease of operation
If FID sensors are positioned at fixed locations constrained by reactor vessel penetrations, then ease of operation is improved, but measurement precision deteriorates due to radial distribution location constraints
Solution Approach 1:
The detector utilizes both radial and axial dimensions for sensor placement, with sensors positioned at multiple radial offsets (e.g., 8 different radial positions) and axial heights (e.g., 12 different axial positions) within the fuel assembly. This multi-dimensional sensor arrangement enables precise radial power distribution measurement without requiring sensors to be positioned at constrained reactor vessel penetration locations, while still maintaining ease of installation through a single integrated unit.
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 configuration provides detailed and accurate power distribution measurements, enabling precise detection of fuel performance anomalies and reactor operation characteristics, reducing maintenance costs and simplifying sensor integration.
Implementation Method 1
a silicon carbide Schottky diode solid state radiation detector that has an electron donor layer such as platinum placed over and spaced above the Schottky contact to contribute high energy Compton and photoelectrical electrons from the platinum layer to the active region of the detector to enhance charged particle collection from incident gamma radiation
Implementation Method 2
an electron donor layer such as platinum placed over and spaced above the Schottky contact to contribute high energy Compton and photoelectrical electrons from the platinum layer to the active region of the detector to enhance charged particle collection from incident gamma radiation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system for measuring gamma spectroscopy of a neutron irradiated material includes a plurality of semiconductor sensors. Each of the semiconductor sensors includes a gamma ray receiving surface disposed above a Shottky layer in contact with an n-doped active layer. The receiving surface is configured to emit electrons upon irradiation by gamma rays. The receiving surface contacts an adjustable telescoping mount configured to adjust the distance between the receiving surface and the Shottky layer. The n-doped layer is fabricated to have a thickness designed to pass through electrons having greater than a defined energy. The combination of adjustable receiving surface and active layer thickness define a minimum and maximum energy response of each of the sensors. Multiple sensors may be integrated in an array in which each sensor has its own energy response. An array of such sensors can measure the gamma spectrum of a material irradiated with neutrons.