Different storage buildings are available for the interim storage of radioactive waste and spent fuel rods. Vitrified high-level waste and spent fuel rods are stored in special thick-walled, tightly sealed transport and storage casks that can weigh up to 140 tonnes in the container storage hall. The casks are constantly monitored to make sure that they remain tightly sealed. Heat is released as radioactive materials decay. The heat emitted by low-level radioactive waste is so low that it is barely detectable. High-level waste releases considerably more heat, but this drops continuously as radioactivity declines, so that the waste can be stored in deep geological repositories after around 40 years. The biggest storage building which, at 98m long is destined to hold low- and medium-level waste, will only be finally commissioned in a few years. Thanks to sufficient interim storage capacity, there is enough time to prepare long-term storage facilities in deep geological repositories.