This stage involves:
- Sealing the reactor
- Decontaminating and dismantling all active and non-active plants and buildings outside the biological shield
- The majority of site decommissioning operations occur in this stage
- The rest of the site may be released for re-use once complete
- A sealed reactor normally remains within its biological shield, kept under a period of care and maintenance
- Generally a period of approximately 50 years from the cessation of operation may be earmarked for this stage