The supervision of nuclear activities by the ASN aims to check that all users of ionising radiation exercise in full their responsibilities and their obligations with regard to radiation protection. In the case of basic nuclear installations (BNIs), this supervision is extended to cover nuclear safety and environmental protection and applies to all stages of the life of the installations: design, creation, commissioning, operation, final shutdown, dismantling. This supervision also includes visits, inspections of all or part of an installation, and examination and analysis of files, documents and data supplied by the operator to justify its actions. Although traditionally more focused on verifying the technical conformity of installations and activities with regulations and standards, this supervision today encompasses a broader dimension taking in human and organisational factors that are harder to assess; it thus includes an examination of individual and collective behaviour, of management, organisation and procedures, based on a variety of indicators (such as events, inspections or relations with the stakeholders (personnel, operators, contractors, trade unions, occupational physicians, inspectorates, and so on)). This supervision by the ASN does not relieve the user of ionising radiation of the need to organise its own in-house supervision of its activities.

The ASN also carries out supervision in premises where exposure of persons to natural radiation can be enhanced owing to the underlying geological context (radon in premises open to the public) or the characteristics of the materials used in industrial processes (non-nuclear industries).

This chapter present the procedures involved in the supervision conducted by the ASN, on the one hand of BNI operators and transporters of radioactive materials, and on the other of users of ionising radiation. It also presents the procedures for monitoring exposure to Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM).

BNI safety, the principles of which are recalled in chapter 2, covers all technical and organisational measures taken at all stages in the design, construction, operation, shutdown and dismantling of nuclear installations in order to ensure normal operation, prevent accidents and limit their effects, in order to protect workers, the population and the environment against the effects of ionising radiation. It also comprises technical measures to optimise management of waste and radioactive discharges.

The safe transport of radioactive materials¹ depends on three main factors:
- first and foremost, on the engineered toughness of the packages,
- on transport reliability and certain specially equipped vehicles,
- on an efficient emergency response in the event of an accident.

The ASN's supervisory activities cover all elements contributing to BNI and TMR safety. It is thus required to look at the equipment constituting the installations and the persons in charge of operating it, at the working and organisational methods from the initial design phases up to dismantling. It examines on the one hand the steps taken concerning safety or the monitoring and limitation of the doses received by the persons working in the installations, and on the other waste management, effluent control and environmental protection procedures.

¹ Transport includes all operations and conditions associated with the movement of radioactive materials, such as packaging design, manufacture, maintenance and repair, and the preparation, shipment, loading, routing, including interim storage in transit, unloading and reception at the final destination of the radioactive material loads and packages.