Nuclear decommissioning

Nuclear decommissioning is the process leading to the irreversible complete or partial closure of a nuclear facility, usually a nuclear reactor, with the ultimate aim at termination of the operating licence. The process usually runs according to a decommissioning plan, including the whole or partial dismantling and decontamination of the facility, ideally resulting in restoration of the environment up to greenfield status. The decommissioning plan is fulfilled when the approved end state of the facility has been reached.

The process typically takes about 15 to 30 years, or many decades more when an interim safe storage period is applied for radioactive decay. Radioactive waste that remains after the decommissioning is either moved to an on-site storage facility where it is still under control of the owner, or moved to a dry cask storage or disposal facility at another location. The final disposal of nuclear waste from past and future decommissioning is a growing still unsolved problem.

Decommissioning is an administrative and technical process. The facility is dismantled to the point that it no longer requires measures for radiation protection. It includes clean-up of radioactive materials. Once a facility is fully decommissioned, no radiological danger should persist. The license will be terminated and the site released from regulatory control. The plant licensee is then no longer responsible for the nuclear safety.

The costs of decommissioning are to be covered by funds that are provided for in a decommissioning plan, which is part of the facility's initial authorization. They may be saved in a decommissioning fund, such as a trust fund.

There are worldwide also hundreds of thousands small nuclear devices and facilities, for medical, industrial and research purposes, that will have to be decommissioned at some point.^[1]