France. Annex II [Geological Disposal of Radioactive Waste: Technological Implications for Retrievability]

The French repository programme provides for the flexibility required by a reversible approach by: - Favouring design choices providing for adequate lifetime of underground structures; - Allowing for simple waste emplacement and retrieval operations; - Adopting a modular and stepwise approach to managing the disposal process. In practical terms, reversibility can be considered for a transient period, up to at least one century. During this period, the level of flexibility it provides for waste management is similar to that of a storage facility. This flexibility is gradually reduced as a series of stepwise management decisions lead to closure, by backfilling access drifts and emplacing a series of seals, thus ensuring the passive long term safety of the repository. Reversibility during the pre-closure phase does not prejudice long term safety, as was verified and stated by the international review team that reviewed the 'Dossier 2005'.