Underground installation for the disposal of nuclear material, such as spent fuel, usually located more than several hundred meters below ground level in a stable geological formation that ensures long term isolation of radionuclides from the environment. In the operating phase the repository will include a reception area which may be above or below ground, as well as container handling and emplacement areas underground. After the final closure, the backfilling of all emplacement areas in the repository will have been completed and all surface activities ceased.