Visualization of Radioactive Substances Using a Freely Moving Gamma-Ray Imager Based on Structure From Motion

2020 ◽  
Author(s):  
Yuki Sato ◽  
Kojiro Minemoto ◽  
Makoto Nemoto ◽  
Tatsuo Torii
Keyword(s):  
Structure From Motion ◽  
Nuclear Power ◽  
Structural Model ◽  
Gamma Ray ◽  
Radioactive Substance ◽  
Compton Camera ◽  
Power Stations ◽  
Experimental Environment ◽  
Radioactive Substances ◽  
Freely Moving

Abstract Technology for measuring and identifying the positions and distributions of radioactive substances is important for decommissioning work sites at nuclear power stations. A three-dimensional (3D) image reconstruction method that locates radioactive substances by integrating Structure-from-Motion (SfM) with a Compton camera (a type of gamma-ray imager) has been developed. From the photographs captured while freely moving in an experimental environment, a 3D structural model of the experimental environment was created. By projecting the radioactive substance image acquired by the Compton camera on the 3D structural model, the positions of the radioactive substance were visualized in 3D space. In a demonstration study, the 137Cs-radiation source was successfully visualized in the experimental environment captured by the freely moving cameras. In addition, how the imaging accuracy is affected by uncertainty in the self-localization of the Compton camera processed by SfM, and by positional uncertainty in the gamma-ray incidence determined by the sensors of the Compton camera was investigated. The created map depicts the positions of radioactive substances inside radiation work environments, such as decommissioning work sites at nuclear power stations.

Consumer Awareness and Attitude on Radiocesium Food Contamination Following Fukushima Incident

2013 ◽  
Vol 8 (sp) ◽  
pp. 762-772 ◽  
Author(s):  
Hiromi Hosono ◽  
◽  
Yuko Kumagai ◽  
Tsutomu Sekizaki
Keyword(s):  
Risk Management ◽  
Nuclear Power ◽  
Food Contamination ◽  
Radioactive Substance ◽  
Knowledge Level ◽  
Insufficient Information ◽  
Consumer Awareness ◽  
Web Based ◽  
Radioactive Substances ◽  
Management Measures

Concerns about radioactive contamination are spreading among consumers after the nuclear power plant incident at Fukushima, Japan in 2011. This study is an attempt to understand how Japanese consumer recognize the risk of radioactive substances in food based on web-based-questionnaire conducted in October 2011, March 2012, and January 2013. Results showedmixed awareness both willing to support radiation-affected areas and willing to avoid the risk of radioactive substances. And deteriorating trust on the radioactive substance management by the stakeholders, and insufficient information provided on risk and management of radioactive substances also were indicated. Among the respondents, those revealed higher satisfaction about risk management measures showed the lower perceived level of risk and their knowledge level were higher.

An evaluation of the equipment tagging process in nuclear power stations

1983 ◽  
Author(s):  
Peter Doyle ◽  
Lothar Schroeder ◽  
Stephen Brewer
Keyword(s):  
Nuclear Power ◽  
Power Stations

Environmental Protection Meets Security of Electricity Supply

2021 ◽  
pp. 1-18
Author(s):  
Ilina Cenevska
Keyword(s):  
Environmental Protection ◽  
Nuclear Power ◽  
Habitats Directive ◽  
Electricity Supply ◽  
The European Union ◽  
Power Stations ◽  
Court Of Justice ◽  
National Energy Policy ◽  
The Relationship ◽  
Practical Implications

Abstract This case comment explores the relationship between two intertwined objectives – ensuring security of electricity supply and environmental protection – in the context of the judgment of the Court of Justice of the European Union in Inter-Environnement Wallonie ASBL and Bond Beter Leefmilieu Vlaanderen ASBL v. Conseil des ministres. The analysis focuses on the application of the Environmental Impact Assessment Directive and the Habitats Directive to the facts of the case, which concerns the extension by a ten-year period of the operation of two Belgian nuclear power stations (Doel 1 and Doel 2) as part of a national energy policy strategy to ensure the security of Belgium's electricity supply. The case comment also considers the legal and practical implications that arise as a result of employing the ‘security of electricity supply’ exemption to enable derogation from the requirements of the aforementioned Directives in circumstances where a Member State considers the security of its electricity supply to be under threat.

Evaluation of the residual stress in stainless steel 304L hydraulically expanded joints

2020 ◽  
pp. 095440892096401
Author(s):  
Ying Hong ◽  
Xuesheng Wang ◽  
Yan Wang ◽  
Zhao Zhang ◽  
Yong Han
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
The Finite Element Method ◽  
Power Stations ◽  
Stainless Steel 304 ◽  
Initial Clearance

Stainless steel 304 L tubes are commonly used in the fabrication of heat exchangers for nuclear power stations. The stress corrosion cracking (SCC) of 304 L tubes in hydraulically expanded tube-to-tubesheet joints is the main reason for the failure of heat exchangers. In this study, 304 L hydraulically expanded joint specimens were prepared and the residual stresses of a tube were evaluated with both an experimental method and the finite element method (FEM). The residual stresses in the outer and inner surfaces of the tube were measured by strain gauges. The expanding and unloading processes of the tube-to-tubesheet joints were simulated by the FEM. Furthermore, an SCC test was carried out to verify the results of the experimental measurement and the FEM. There was good agreement between the FEM and the experimental results. The distribution of the residual stress of the tube in the expanded joint was revealed by the FEM. The effects of the expansion pressure, initial tube-to-hole clearance, and yield strength of the tube on the residual stress in the transition zone that lay between the expanded and unexpanded region of the tube were investigated. The results showed that the residual stress of the expanded joint reached the maximum value when the initial clearance was eliminated. The residual stress level decreased with the decrease of the initial tube-to-hole clearance and yield strength. Finally, an effective method that would reduce the residual stress without losing tightness was proposed.

C-SPRINT: a prototype Compton camera system for low energy gamma ray imaging

2002 ◽  
Author(s):  
J.W. LeBlanc ◽  
N.H. Clinthorne ◽  
C.-H. Hua ◽  
E. Nygard ◽  
W.L. Rogers ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Low Energy ◽  
Compton Camera ◽  
Camera System ◽  
Gamma Ray Imaging ◽  
Energy Gamma

Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1369-1378 ◽  
Author(s):  
Georg F. Schwarz ◽  
Ladislaus Rybach ◽  
Emile E. Klingelé
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Gamma Ray ◽  
Point Sources ◽  
Swiss Alps ◽  
Artificial Radioactivity ◽  
Radiation Level ◽  
Satellite Navigation System ◽  
Emergency Situations

Airborne radiometric surveys are finding increasingly wider applications in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma‐ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose‐rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Gösgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

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