The decommissioning of a nuclear installation includes all activities necessary to ensure that the installation or site can be used for other purposes, that the installation no longer constitutes a source of radiological hazard and that it is no longer subject to nuclear energy legislation. The operator of a nuclear installation first creates a decommissioning project. ENSI drafts a safety statement for the attention of DETEC. The latter issues the decommissioning order. The oversight activities of ENSI include, among other things, the release of dismantling phases and inspections.

The following decommissioning projects are currently in progress:

• Mühleberg Nuclear Power Plant
• PSI research reactors

The following nuclear installations have already been decommissioned:

• Lucens experimental nuclear power plant
• Basel University Research Reactor