ASN Report 2018

∙ ∙ Diagraphy (logging), which enables the geological properties of the subsoil to be examined by inserting a measurement probe containing a source of cobalt-60, caesium-137, americium-241 or californium-252. Some sources used are high-activity sealed sources. 1.1.2  –  Neutron activation Neutron activation consists in irradiating a sample with a flux of neutrons to activate the atoms in the sample. The number and the energy of the gamma photons emitted by the sample in response to the neutrons received are analysed. The information collected is used to determine the concentration of atoms in the analysed material. This technology is used in archaeology to characterize ancient objects, in geochemistry for mining prospecting and in industry (study of the composition of semiconductors, analysis of raw mixes in cement works). Given the activation of the material analysed, this requires particular vigilance with regard to the nature of the objects analysed. Article R. 1333-2 of the Public Health Code prohibits the use of materials and waste originating from a nuclear activity for the manufacture of consumer goods and construction products if they are, or could be, contaminated by radionuclides, including by activation (see point 2.2.1). 1.1.3  –  Other common applications Sealed radioactive sources can also be used for: ∙ ∙ industrial irradiation, used for sterilization in particular (see point 3.2.1); ∙ ∙ gamma radiography which is a non-destructive inspection method (see point 3.3.1); ∙ ∙ eliminating static electricity; ∙ ∙ calibrating radioactivity measurement devices (radiation metrology); ∙ ∙ practical teaching work concerning radioactivity phenomena; ∙ ∙ detection by electron capture. This technique uses sources of nickel-63 in gaseous phase chromatographs and can be used to detect and dose various chemical elements; ∙ ∙ ion mobility spectrometry used in devices that are often portable and used to detect explosives, drugs or toxic products; ∙ ∙ detection by X-ray fluorescence. This technique is used in particular for detecting lead in paint. The portable devices used today contain sources of cadmium-109 (half-life 464 days) or cobalt-57 (half-life of 270 days). The activity of these sources can range from 400 MBq to 1,500 MBq. This technique, which uses a large number of radioactive sources nationwide (nearly 4,000 sources), is the result of a legislative system designed to prevent lead poisoning in children by requiring a check on the lead concentration in paints used in residential buildings constructed before 1 January 1949 in case of sale, a new rental contract, or work significantly affecting the coatings in the common parts of the building. Graph 1 specifies the number of facilities authorized to use sealed radioactive sources for the applications identified. It illustrates the diversity of these applications and their development over the last five years. It should be noted that a given facility may carry out several of these activities, and if it does, it appears in Graph 1 and the following diagrams for each activity. 1.2  ̶  Uses of unsealed radioactive sources The main radionuclides used in the form of unsealed sources in non-medical applications are phosphorus-32 or 33, carbon-14, sulphur-35, chromium-51, iodine-125 and tritium. They are used in particular in research and in the pharmaceutical sector. They are a powerful investigative tool in cellular and molecular biology. Using radioactive tracers incorporated into molecules is common practice in biological research. There are also several industrial uses, for example as tracers or for calibration or teaching purposes. Unsealed sources are used as tracers for Used of sealed radioactive sources 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 Calibration X-ray fluorescence analysis Density measurement and weighing Thickness measurement Atmospheric dust measurement Thickness of thin layers Level measurement Paper weight measurement Humidity and density Diagraphy (logging) Elimination of static electricity Implementation of neutron sources Teaching Analysis Research Chromatography Electron capture detectors Gamma radiography 0 100 200 300 400 500 600 700 800 2014 2015 2016 2017 2018 Number of facilities licensed Graph 1 ASN report on the state of nuclear safety and radiation protection in France in 2018  233 08 – SOURCES OF IONISING RADIATION AND THEIR INDUSTRIAL, VETERINARY AND RESEARCH APPLICATIONS 08