Collimated Detector 3D Mapping Nuclear Contamination
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Solution Overview
Problem
Current methods for determining the depth distribution of radionuclides in nuclear facilities, particularly in concrete enclosures, are inadequate for sources of unknown shape and are not suitable for rapid, precise, in-situ assessment, limiting the optimization of waste sorting and radiation protection during dismantling.
Innovation Solution
A method and system using a collimated radiation detector to perform measurements at different distances and energies, analyzing the data by subdividing the cylindrical region into meshes to estimate radioactivity levels through an inversion of a linear system, allowing for non-destructive, in-situ characterization of radiological contamination without assumptions about the depth distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional in-situ measurement methods are used to determine radionuclide depth distribution, then measurement speed is improved, but measurement precision deteriorates due to inability to accurately determine depth distribution
Solution Approach 1:
The patent transitions from conventional surface-level or single-point depth measurements to a three-dimensional mapping approach. By using a collimated detector that scans and maps radioactivity in three dimensions (x, y, z coordinates), the system simultaneously achieves rapid measurement and precise depth distribution determination, resolving the contradiction between speed and precision.
2Measurement precision
If spectrochemical analyzes of cored elements are performed in the laboratory, then measurement precision is improved, but loss of time increases due to laboratory processing requirements
Solution Approach 1:
The patent replaces the mechanical and chemical processes of core sampling, transportation, and laboratory spectrochemical analysis with a non-destructive in-situ gamma spectrometry measurement system. The collimated detector directly measures radionuclide depth distribution in the concrete structure without physical sampling, eliminating time losses while maintaining measurement precision.
Solution Approach 2:
The measurement system performs the analysis directly at the measurement location using the existing radionuclides in the concrete structure as the source. The in-situ gamma spectrometry system utilizes the natural gamma emissions from the contaminated concrete without requiring external sampling or transportation, making the system self-sufficient and eliminating laboratory processing time.
3Device complexity
If methods assuming uniform spatial distribution of radionuclides are used, then device complexity is reduced, but measurement precision deteriorates due to inability to characterize heterogeneous sources
Solution Approach 1:
The patent divides the concrete structure into multiple discrete volumetric elements or voxels in three-dimensional space. Each voxel is independently characterized for its radionuclide content and depth distribution. This segmentation allows the system to model heterogeneous sources accurately while maintaining manageable computational complexity through systematic processing of individual elements.
Solution Approach 2:
The patent applies different measurement and analysis parameters to different spatial locations within the concrete structure. The collimated detector measures local radioactivity characteristics at each position, and the analysis adapts to local heterogeneities in radionuclide distribution. This local quality approach enables precise characterization of heterogeneous sources without requiring overly complex global measurement systems.
4Measurement precision
If invasive core sampling methods are used to determine depth distribution, then measurement precision is improved, but object-generated harmful factors increase due to destruction of the inspected structure
Solution Approach 1:
The patent replaces invasive mechanical core sampling with non-destructive gamma spectrometry measurements. The collimated detector measures radionuclide depth distribution through external gamma ray detection without physical contact or damage to the concrete structure, eliminating harmful effects while maintaining measurement precision.
Solution Approach 2:
The patent uses gamma radiation as an intermediary to obtain information about radionuclide depth distribution without direct physical intervention in the concrete structure. The gamma rays penetrate the concrete and carry information about the radionuclide distribution, allowing indirect measurement that avoids structural damage while achieving high measurement precision.
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 accurate, rapid determination of radiological contamination depth, optimizing waste separation and classification, and improving radiation protection by providing a three-dimensional map of contamination levels in nuclear facilities.
Implementation Method 1
perform several measurements of the radiation received by the radiation detector (2) for different emission energies and different distances
Implementation Method 2
The radiation detector (2) is collimated to receive radiation from a cylindrical region (25)
Implementation Method 3
C is a matrix having as components pre-calculated values as a function: of the emission energies of the radiation in the measurements carried out; distances, during the measurements carried out, between the radiation detector (2) and the surface (20)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The method for inspecting a nuclear facility comprises the steps consisting of: placing a radiation detector (2) in front of a surface of a portion of the facility (1), the radiation detector (2) being collimated to receive radiation from a cylindrical region of the portion of the facility; carrying out a plurality of measurements of radiation received by the radiation detector for different transmission energies and different distances, along the axis of the cylindrical region, between the radiation detector and surface of the portion of the facility; and analysing the radiation measurements by subdividing the cylindrical region into a plurality of meshes (3) so as to estimate respective levels of radioactivity in the meshes (3).