What is nuclear decommissioning?

The decommissioning of a nuclear power station occurs when it reaches the end of its life and no longer generates electricity. It is legally mandated. A power company must plan for decommissioning as part of the process of obtaining a licence to manage a nuclear site.

Defueling

Used fuel comprises the majority of the radioactive material at a nuclear power station. It is the responsibility of the operating company to ensure it is safely removed.

A special machine is used to extract the fuel from each of the more than 300 channels contained in each reactor. Fuel elements are then placed into a cooling pond for a 90-day period. After this has taken place, the fuel is ready to be packaged and stored in flasks, around 400 flasks per site.

The flasks will be transferred to a special facility for additional cooling until they are ready for final disposal. The defueling of an entire power station may take up to five years.

Waste Treatment and Removal

Once defueling is complete, the operating company transfers responsibility for the site to the Nuclear Decommissioning Authority, or NDA, which will designate its subsidiary Nuclear Restoration Services to carry out the next stage of decommissioning.

Waste, both radiological and non-radiological, will be treated and removed. Sometimes, this involves the construction of additional facilities at the site for radioactive waste management processing, or for long-term storage of radioactive material. Companies such as RAICo, found at https://raico.org/, minimise the need for direct human contact with radioactive materials through the use of robotics.

Deconstruction of External Facilities

All buildings, equipment and services that are no longer required can now be demolished, until only the main reactor building remains. After the allowed period for extended radioactive material storage at the site has expired, the rest of the site can be cleared and restored as much as possible, in line with environmental regulations.

It is a lengthy and complex process to decommission a nuclear power station. Every stage must be conducted safely to ensure the protection of workers, the public and the local ecosystem.