Enriched CZT Detector Collimation for Molten Salt Void Fraction

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Solution Overview

Problem

Traditional CZT detectors are impractical for use in high neutron flux environments like molten salt reactors due to high neutron absorption by cadmium-113 isotopes, leading to count saturation and unusable gamma ray spectra.

Innovation Solution

Employing a CZT detector with enriched CZT crystals substantially devoid of cadmium-113, combined with a collimator for thermal insulation and neutron filtration, allowing gamma ray data capture and void fraction determination in molten salt reactors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional CZT detectors with cadmium-113 isotopes are used in high neutron flux environments, then gamma ray detection capability is maintained, but neutron absorption causes count saturation and renders the detector useless

Engineering Contradiction:

Improvedetector functionality in high neutron flux environmentVSAvoidneutron absorption by cadmium-113

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the harmful cadmium-113 isotope from the CZT detector material composition. By using depleted cadmium or alternative materials without cadmium-113, the detector eliminates the primary source of neutron absorption that caused count saturation, while maintaining gamma ray detection capability through the remaining CZT material properties.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the isotopic composition parameter of the cadmium material in the CZT detector. Instead of using natural cadmium with its problematic cadmium-113 isotope, the material is modified to have depleted or alternative isotopic compositions, fundamentally altering the neutron interaction properties while preserving the detector's operational functionality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If enriched CZT crystals devoid of cadmium-113 are used, then neutron absorption issues are overcome, but manufacturing complexity increases

Engineering Contradiction:

Improvedetector performance in high neutron flux environmentVSAvoidCZT crystal production without cadmium-113

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs depleted cadmium or alternative materials that may have shorter operational lifetimes or require more frequent replacement, but these materials are easier and less expensive to manufacture without the complex isotopic enrichment processes required for traditional CZT detectors, offsetting the manufacturing simplicity advantage against the reduced material lifespan.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If collimator assembly is added for thermal insulation and neutron filtration, then detector protection is improved, but device complexity increases

Engineering Contradiction:

Improvethermal and neutron shieldingVSAvoiddetector system structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The collimator assembly is designed to perform multiple functions simultaneously: it provides thermal insulation to protect the detector from heat, filters neutrons to reduce neutron absorption, and collimates gamma rays to improve detection geometry. By combining these functions into a single component structure, the patent reduces the need for separate shielding elements, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables reliable gamma ray spectrum data collection and determination of void fraction in high neutron flux environments, overcoming neutron absorption issues and providing accurate reactor operation insights.

Implementation Method 1

a collimator assembly coupled to and interposed between the CZT detector and a molten salt reactor system and operable to filter gamma rays emitted from radionuclides of a domain of the molten salt reactor system thereby producing filtered gamma rays

Methodology Applied

Scientific EffectGamma ray filtration: Filter (optical)

Implementation Method 2

The CZT detector is operable to receive the filtered gamma rays and produce spectroscopy data representative of an inventory of radionuclides within the domain of the molten salt reactor system from the filtered gamma rays

Methodology Applied

Scientific EffectGamma ray detection: Photoelectric Effect

Implementation Method 3

The at least one enriched CZT crystal is substantially devoid of cadmium-113 isotopes

Methodology Applied

Scientific EffectNeutron absorption blocking: Absorption (physical)

Data Source

PatentUS20260056336A1CZT detectors and methods of use thereof

Publication Date: 2026.02.26 GEORGIA TECH RES CORP

AI summary

Fission reactions within a molten salt reactor may produce gaseous fission products. These fission products may be removed through a variety of methods. However, proper removal of such fission products requires a thorough understanding of the proportion of gaseous space to fluid space within the component being interrogated, known as the void fraction. The present invention provides a means for determining the void fraction within such a component utilizing an enrich cadmium zinc telluride detector to produce collimated radiation data. The collimated radiation data may then be used to compute a mean void fraction across the domain being interrogated.