Following the final shutdown of a nuclear facility, a post-operational phase takes place during which preparatory work for decommissioning is carried out. Decommissioning after the post-operational phase requires a comprehensive licensing procedure, addressing in particular radiation protection and potential environmental impacts.

In addition to power reactors, other nuclear facilities licensed under Section 7 of the Atomic Energy Act – such as prototype and research reactors and nuclear fuel cycle facilities – must also be decommissioned at the end of their operating life. BASE provides tables listing German nuclear reactors and facilities that are in operation or undergoing decommissioning.

The German Atomic Energy Act (AtG) specified residual electricity volumes for each nuclear power plant in operation in Germany, defining how much electricity each plant was permitted to generate before ist operating licence expired.

Since August 2011, the Atomic Energy Act has stipulated fixed shutdown dates for all nuclear power plants, leading ot he gradual shutdown and decommissioning of all power reactors in Germany.

The last three nuclear power plants were permanently shut down on 15 April 2023.

Contamination and activation

Any facility where radioactive substances have been handled is contaminated to varying degrees, meaning residues may be found – for example:

• on surfaces,
• in tanks,
• or in piping systems.

Such contamination can be removed by appropriate decontamination procedures, typically through mechanical or chemical removal of surface layers. If successful, the affected materials can be released for recycling or disposed of as non-radioactive material, with only the removed surface layers (and, where applicable, auxiliary materials) remaining as radioactive waste.

Decontamination therefore provides an opportunity to significantly reduce the volume of radioactive waste generated during the decommissioning phase of a nuclear facility. In reactors, activation of materials near the core also occurs, whereby a small portion of the material itself becomes radioactive due to neutron irradiation during operation.

Decommissioning strategies

Various decommissioning strategies exist. Facilities can either be

• dismantled immediately after shutdown,
• or placed in safe enclosure for several years to allow radioactive decay to reduce the activity inventory before subsequent dismantling (safe enclosure).

According to the Atomic Energy Act, power reactors whose licence for power operation has expired must be decommissioned without undue delay and subsequently dismantled.

Hybrid approaches are also possible, combining both strategies. The overall decommissioning process can be optimised, for example, by removing large components and storing them temporarily for later dismantling.

In Germany, numerous power and prototype reactors, research reactors, and nuclear fuel cycle facilities have already been decommissioned. Some facilities have undergone complete dismantling, meaning that plant buildings were demolished and sites cleared and remediated. Germany therefore possesses extensive practical experience in nuclear facility decommissioning.

Guide for the decommissioning of nuclear facilities

There is no stand-alone legislation for decommissioning nuclear facilities in Germany. Instead, decommissioning is integrated into the existing nuclear legislation. The Decommissioning Guide provides an overview of the legal requirements and procedural aspects to be considered during decommissioning.

The guideline for decommissioning, safe enclosure, and dismantling of facilities or facility parts under Section 7 of the Atomic Energy Act is available for download in the Handbook on Reactor Safety and Radiation Protection, under the heading “3 Announcements of the BMUKN and the former BMI”.