Europe constitutes the priority field of international action for ASN, which thereby intends contributing to the construction of a Europe of nuclear safety, of safety of management of nuclear waste and spent fuel and of radiation protection.
The Treaties constitute the "primary legislation" of the European Union, comparable with constitutional law at national level. They define the fundamental elements of the Union, including more specifically the competences, the legislative procedures and the powers attributed.
The Treaty establishing the European Community of Atomic Energy (Euratom)
Signed in 1957, the Euratom treaty coordinates the member states' ongoing or planned research programmes with a view to the civil use of nuclear energy.
The Euratom treaty has allowed the harmonised development across Europe of a strict system for the control of nuclear safety  (chapter 7) and radiation protection (chapter 3). Despite the fact that the Euratom Treaty does not give the Community strict and exclusive competence in certain areas, it nevertheless remains a real source of added value for its members.
This is because on the basis of this treaty the European Commission has adopted recommendations and decisions which, despite being non-binding, establish European standards (chapter 3).
It is also important to emphasise that other EC policies such as those for the environment and research also have a considerable impact on the nuclear sector.
The added value of Euratom and the EU is particularly obvious in the context of enlargement of the European Union. Thanks to Euratom, the EU has a harmonised approach to nuclear energy which candidate countries are obliged to adopt. The eastward extensions of the EU place the emphasis on the nuclear sector, and more specifically on the questions concerning nuclear safety.
This means the legislative acts adopted by the European institutions in application of the provisions of the treaties. The main legally binding acts are the regulations and the directives :
A regulation is a general and mandatory act adopted by the Council of the European Union with / or without the European Parliament, or by the Commission alone, and which is directly applicable in the member states. A directive is adopted by the same European institutions but needs to be implemented at national level for being effective. It binds the 28 countries through the objective to be achieved but leaves them free to choose the form and means used to achieve this objective.
The decisional path of the EURATOM treaty
In its broad lines the institutional framework of the Euratom treaty is similar to that of the EU treaty and is underpinned by the same "institutional triangle" (Council, Commission and European Parliament). Performance of the tasks entrusted to the Community is thus ensured not only by the European Parliament, the Commission and the Council, but also by the European Court of Justice and the European Court of Auditors. Each institution acts within the limits of the attributions conferred upon it by the treaty. The Council and the Commission are assisted by an Economic and Social Committee exercising consultative functions.
 En France, au sens de la loi TSN la sécurité nucléaire recouvre la sécurité civile en cas d’accident, la protection des installations contre les actes de malveillance, la sûreté nucléaire, c’est-à-dire le fonctionnement sécurisé de l’installation, et la radioprotection, qui vise à protéger les personnes et l’environnement contre les effets de rayonnements ionisants. Au sens de l’AIEA la sécurité nucléaire recouvre les mesures visant à empêcher et à détecter un vol, un sabotage, un accès non autorisé, un transfert illégal ou d’autres actes malveillants mettant en jeu des matières nucléaires et autres matières radioactives ou les installations associées et à intervenir en pareil cas.