There are two main strategies for decommissioning: immediate dismantling or deferred dismantling after safe enclosure. The German Atomic Energy Act (AtG) originally considered both strategies as equivalent. However, the Act on the Reorganisation of Responsibility in Nuclear Waste Management amended Section 7, paragraph 3 of the AtG ) of the AtG. It stipulates that nuclear power plants have to be decommissioned and dismantled without delay if their license has expired or operation has been terminated and the operators are obligated to contribute to the fund pursuant to Section 2 (1) sentence 1 of the Act on the Nuclear Waste Management Fund. Safe enclosure is no longer an option for nuclear power plants. Temporary derogations from this may be approved by the competent authority in individual cases for parts of nuclear facilities, in so far as this is deemed necessary for radiation protection reasons.
Irrespective of the decommissioning strategy, the permanent shutdown is followed by a post-operational phase before the start of the actual decommissioning. During this period, the fuel assemblies may be removed, or the operational media and waste disposed of, insofar as this is covered by the operating licence for the nuclear power plant. Decommissioning and dismantling activities may commence only when the corresponding licence has been granted.