Office for Nuclear Regulation


Decommissioning is the process of dealing with redundant nuclear facilities that have reached the end of their operational life. The objective of decommissioning a nuclear installation is either:

Decommissioning is usually conducted in three stages:

Throughout the decommissioning process, ONR ensures that nuclear licensees adequately control all remaining hazards on site. This is achieved through a programme of targeted interventions with licensees, designed to ensure that licensees have suitable arrangements in place for decommissioning in order to progressively reduce the risks. ONR reviews licensees decommissioning arrangements and ensures that licensees adopt relevant good practice. Relevant good practice is reflected in ONR's guidance notes to its inspectors, which are made publicly available.

Initially, all licensees must produce a clear decommissioning strategy that will demonstrate how all redundant, operational and proposed plants can be decommissioned safely at the end of its operational life. For larger decommissioning projects or projects containing a high nuclear risk, ONR may require the licensee to divide the project into series of sequential stages with the objective of each stage to deliver significant hazard reduction.

Licensees ongoing safety and decommissioning performance is assessed through regular site inspections to ensure that the licensee is making steady progress with decommissioning, and maintaining nuclear safety.

Environmental Impact Assessment of Decommissioning Regulations (EIADR)

As part of the decommissioning process, there is a requirementto assess the potential environmental impact of projects to decommission nuclear facilities.

Quinquennial reviews

Each nuclear licensee is expected to produce and maintain a decommissioning strategy for the site(s) it is responsible for.