Schottky Diode Gamma Detector Layout for Localized In-Core Measurements
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Solution Overview
Problem
Existing in-core radiation detection systems for nuclear reactors face challenges in obtaining highly localized and detailed measurements due to their complexity, size, and high operation and maintenance costs, which limits their ability to verify performance predictions and ensure safe reactor operation.
Innovation Solution
The development of an in-core detector system that includes a housing with a plurality of gamma detectors, each comprising a Schottky diode with a Schottky contact and an Ohmic contact, a photoelectron source material, and leads positioned to minimize interference, allowing for radial offsetting and maximizing detector density for improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If movable in-core detector systems are used to obtain detailed measurements, then measurement precision is improved, but device complexity and operation costs increase
Solution Approach 1:
The patent replaces the mechanical movable detector system with a fixed in-core detector system that uses semiconductor physics (Schottky diodes) to achieve measurements. This substitution eliminates the mechanical complexity of movable systems while maintaining measurement capability through the physical properties of semiconductor materials in radiation fields.
Solution Approach 2:
The patent changes the fundamental measurement parameter from neutron detection to gamma radiation detection using Schottky diodes. This parameter change enables fixed positioning while achieving detailed measurements through the energy-dependent response of the semiconductor detectors to gamma radiation from fission products.
2Device complexity
If fixed in-core detector systems are used to reduce complexity, then device complexity is reduced, but measurement precision deteriorates due to averaging
Solution Approach 1:
The patent divides the detection function into multiple discrete Schottky diode detectors positioned at specific radial locations within the fuel assembly. Each detector provides localized measurements at its specific position, and the collective array of segmented detectors reconstructs the detailed three-dimensional power distribution without mechanical movement.
Solution Approach 2:
The patent transitions from one-dimensional axial measurements to three-dimensional spatial measurements by positioning detectors at multiple radial locations (e.g., 0.5 inches, 1.0 inches, 1.5 inches from assembly center) combined with axial positions. This dimensional expansion enables localized measurements throughout the fuel assembly volume using a fixed system.
3Reliability
If traditional detection systems are used to ensure reliability, then reliability is improved, but loss of substance increases due to piping and sensor requirements
Solution Approach 1:
The patent extracts the detection function from complex mechanical systems with piping and sensors, isolating it to simple semiconductor Schottky diodes that require no external connections, cooling systems, or mechanical support infrastructure. This extraction eliminates the material consumption associated with traditional system components while maintaining detection reliability.
Solution Approach 2:
The Schottky diode detectors are designed to operate autonomously within the radiation field, converting gamma radiation directly into electrical signals without requiring external power, cooling, or maintenance. The detectors serve themselves by utilizing the energy from the radiation environment to generate their own measurement signals.
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 system enables continuous, real-time, and highly localized measurements of power distribution within nuclear reactors, enhancing the accuracy of performance predictions and improving reactor operation and safety without the high costs associated with traditional systems.
Implementation Method 1
a photoelectron source material configured to transfer electrons to the active region of the Schottky diode upon contact with gamma radiation emitted by the nuclear reactor
Implementation Method 2
each gamma detector of the plurality of gamma detectors includes a Schottky diode having an active semiconductor region and a Schottky contact over at least a portion of the active semiconductor region
Data Source
AI summary
An in-core detector configured to measure a power distribution in a nuclear reactor is disclosed herein. The in-core detector includes a housing configured to be placed within a predetermined location of the nuclear reactor and a plurality of a gamma detectors. Each gamma detector of the plurality of gamma detectors includes a Schottky diode including an active semiconductor region and a Schottky contact, an Ohmic contact, a photoelectron source material configured to transfer electrons to the active region upon contact with gamma radiation, and a first and second lead. The plurality of gamma detectors are positioned within the housing such that each gamma detector of the plurality of gamma detectors is radially offset relative to an adjacent gamma detector of the plurality of gamma detectors, such that the first and second leads of each gamma detector are offset relative to the first and second leads of the adjacent gamma detector.