1.1.2 Neutron activation Neutron activation consists in irradiating a sample with a flux of neutrons to activate the atoms in the sample, which renders the sample radioactive. 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 characterise 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 analysed material, this requires particular vigilance with regard to the nature of the objects analysed. Articles R.1333-2 and R.1333-3 of the Public Health Code prohibit 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. Waivers may however be granted in a very limited number of cases (see point 2.2.1). 1.1.3 Other common applications Sealed radioactive sources can also be used for: ∙gamma radiography which is a non- destructive inspection method (see point 3.3); ∙industrial irradiation, used for sterilisation in particular (see point 3.2); ∙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 for any sale, new rental contract, or work significantly affecting the coatings in the common parts of the building. Graphs 1A and 1B (see previous page) show the number of licensed, registered or notified facilities using sealed radioactive sources in the identified applications. They illustrate 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 activities, and if it does, it appears in Graph 1 (A and B) and the following diagrams for each activity; ∙the breakdown between the licensing, registration and notification system (radioactive sources and electrical devices emitting ionising radiation) for a given application is not yet stabilised, because the changes of administrative system concerning the nuclear activities subject to notification since 1 January 2019, are going to extend through to 1 July 2026 (see point 2.4.2) for those subject to registration since 1 July 2021. 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 constitute a powerful investigative tool in cellular and molecular biology. Using radioactive tracers incorporated into molecules is common practice in biological research. There are also a number of industrial uses, for example as tracers or for calibration or teaching purposes Unsealed sources are used as tracers for measuring wear, detecting leaks or friction spots, building hydrodynamic models and in hydrology. As at 31 December 2024, 532 facilities were authorised to use unsealed radioactive sources (to which can be added 139 facilities covered by the registration system). Graph 2 specifies the number of facilities licensed (or registered) to use unsealed radioactive sources, according to the various listed applications, in the last five years. 1.3 Uses of electrical devices emitting ionising radiation 1.3.1 Main industrial applications In industry, electrical devices emitting ionising radiation are used mainly in non-destructive testing, where they replace devices containing radioactive sources. Graphs 3A and 3B (see next page) show the number of facilities using electrical devices generating ionising radiation in the listed applications under the licensing, registration or notification systems respectively. They illustrate the diversity of these applications and their development over the last five years. This development is closely related to the regulatory changes which have gradually created a new system of licensing or notification, and more recently registration (see point 2.4.2), concerning the use of these devices. At present, measures to bring the professionals concerned into compliance are very widely engaged in many activity sectors. The electrical devices emitting ionising radiation are chiefly X-ray generators. They are used in industry for non-destructive structural analyses (analysis techniques such as tomography, diffractometry, also called X-ray crystallography, etc.), checking the quality of weld beads or inspecting materials for fatigue (in aeronautics in particular). GRAPH 2 Use of unsealed radioactive sources by end‑purpose 0 100 200 300 400 500 600 700 800 1 4 9 49 13 1 15 11 1 9 84 112 2 7 Number of facilities licensed or registered Research Use of tracers Calibration Teaching 2020 Licences 2021 Licences 2022 Licences 2023 Licences 2024 Licences 2021 Registrations 2022 Registrations 2023 Registrations 2024 Registrations ASN Report on the state of nuclear safety and radiation protection in France in 2024 251 11 12 13 14 15 AP 10 09 Sources of ionising radiation and their industrial, veterinary and research applications 08 01 02 03 04 05 06 07
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