• Performance of final shutdown and dismantling operations

The final shutdown and dismantling operations, which only begin after any decommissioning operations, comprise two successive sets of operations:

- final shutdown operations, which mainly consist of disassembly of the equipment outside the nuclear island and not required for continued monitoring of nuclear island safety, maintaining or reinforcing of the containment barriers or establishing a radioactivity balance;

- dismantling work on the nuclear part of the plant. This work can start as soon as the final shutdown operations are completed or can be delayed with a view to taking advantage of radioactive decay in certain activated or contaminated materials.

In some cases, operations such as the unloading and removal of nuclear material, the disposal of fluids, or decontamination and clean-up operations can be performed under the provisions of the authorisation decree for the plant considered. To do so, these operations must involve compliance with previously imposed requirements and with the safety analysis report and general operating rules currently in force. In all other cases, such operations come under the provisions of the final shutdown and dismantling decree.

• Installation declassification and contractual easements

If dismantling work reaches the stage where the total radioactivity of the remaining radioactive substances is below the minimum level necessitating classification as a Basic Nuclear Installation, the plant can be declassified and removed from the list of BNIs in accordance with the procedure laid down in its final shutdown and dismantling decree.

Depending on the residual level of radioactivity, the installation may then be subject to the legislation applicable to ICPEs (articles L. 511-1 to L. 517-2 of the Environment Code) and therefore subject to a registration or licensing procedure.

In order to retain a trace of the past existence of a BNI on a site, and provide for any possible future restrictions on use of the installation, the ASN may consider establishment of an easement as a pre-condition for declassification of the installation.

The final shutdown and dismantling decree for an installation therefore requires that after the dismantling operations and to support its installation declassification application, the operator submit an updated study of the impact of the installation on its environment, in order to assess the need for any restrictions on the future use of the installation and/or site. If this does prove necessary, a contractual easement on behalf of the State may be established by the ASN, after discussion with the local State services concerned, proposed to the landowner and, as applicable, the owner of the remaining buildings. This proposed easement may comprise general precautionary easements (minimum inspections required when earthworks are carried out on the land, ban on construction of buildings housing vulnerable persons, inclusion of the easement in the land registry) and may, as required, provide for procedures specific to the site concerned, according to its state after dismantling.

When such a contractual easement is put in place, it is communicated by the ASN when the ministerial decision is made to declassify the installation from its BNI status.