ASN Report 2017
290 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 10 - Sources of ionising radiation and their industrial, veterinary and research applications 1. Industrial, research and veterinary uses of radioactive sources 1.1 Sealed radioactive sources Sealed radioactive sources are defined as sources whose structure or packaging, in normal use, prevents any dispersion of radioactive substances into the surrounding environment. Their main uses are presented below. 1.1.1 Industrial irradiation Industrial irradiation is used for sterilising medical equipment, pharmaceutical or cosmetic products and for the conservation of foodstuffs. It can also be used to modify the properties of materials, such as for hardening polymers. These consumer product irradiation techniques can be authorised because, after being treated, the products display no residual artificial radioactivity (the products are sterilised by passing through radiation without themselves being “activated” by the treatment). Industrial irradiators often use cobalt-60 sources, whose activity can be very high and exceeds 250,000 terabecquerels (TBq). Some of these installations are classified as BNIs (see chapter 14). In many sectors, X-ray generators are gradually replacing high- activity sealed sources for the irradiation of products (see point 2). 1.1.2 Gamma radiography Gamma radiography is a non-destructive inspection method used for detecting homogeneity defects inmaterials such as weld I ndustrial and research sectors have been using sources of ionising radiation in a wide range of applications and locations for many years now. The purpose of the radiation protection regulations is to check that the safety of workers, the public and the environment is ensured. This protection involves more specifically ensuring proper management of the sources, which are often portable and used on worksites, and monitoring the conditions of their possession, use and disposal, from fabrication through to end-of-life. It also involves monitoring the main stakeholders, that is to say the source manufacturers and suppliers, and enhancing their accountability. The ongoing updating of the regulatory framework for nuclear activities established by the Public Health Code and the Labour Code (see chapter 3) is leading to a tightening of the principle of justification, consideration of natural radionuclides, the implementation of a more graded approach in the administrative systems and measures to protect the sources against malicious acts. These changes will bring substantial modifications in the oversight of industrial, research and veterinary activities which will be introduced progressively as from 2018. The radiation sources used are either radionuclides - essentially artificial - in sealed or unsealed sources, or electrical devices generating ionising radiation. The practices/applications presented in this chapter concern the manufacture and distribution of all sources, the industrial, research and veterinary uses (medical activities are presented in chapter 9) and activities not regulated under the Basic Nuclear Installations (BNI) System (these are presented in chapters 12, 13 and 14). beads. It involves obtaining a radiographic image on silver-based or digital media using the gamma rays emitted by a radioactive source and passing through the object to inspect. It is widely used in fabrication and maintenance operations in diverse industrial sectors such as boilermaking, petrochemicals, nuclear power plants, public works, aeronautics and armament. Gamma radiography devices contain high activity sealed sources, mainly iridium-192, cobalt-60 or selenium-75, whose activity can reach about twenty terabecquerels. A gamma radiography device is usually a mobile device which can be moved from one worksite to another. It consists primarily of: ཛྷ ཛྷ a source projector which acts as a storage container and ensures radiological protection when the source is not in use; ཛྷ ཛྷ a guide tube which guides the movement of the source up to the object to be examined; ཛྷ ཛྷ and a remote control cable allowing remote manipulation by the operator. When the source is ejected out of the projector, the dose rates can reach several grays per hour one metre from the device, depending on the radionuclide and its activity level. On account of the activity of the sources and the movement of the sources outside the storage container when the device is being used, gamma radiography can entail significant risks for the operators in the event of incorrect use, failure to comply with radiation protection rules, or operating incidents. Furthermore, these gamma radiography activities are often carried out on work sites under difficult conditions (working at night, or in places that are exposed to the elements, or in cramped spaces). This is therefore an activity with serious radiation protection implications that figures among ASN’s inspection priorities.