Kozloduy Radioactive Waste Repository Expected to Become Operational Within Two Years

Construction of the first phase of the repository for low- and intermediate-level radioactive waste in Kozloduy has been completed. With this, Bulgaria resolves the long-standing issue of storing this type of waste.

However, for the facility to begin actual operations, it must still obtain an operating licence.

The question of storing high-level waste, including spent nuclear fuel, remains unresolved. What options does the country have for this type of waste?

Over 1,000 reinforced concrete cubes filled with radioactive waste are already awaiting storage in the new repository. The construction of the first phase of the facility took nearly twenty years in total, having started on 29 August 2017.

Ira Stefanov – Chief Engineer of the National Repository:
“The first phase includes the construction of the first platform along with its accompanying building and facilities. The first platform contains 22 disposal cells, each of which is independent, seismically qualified, and self-contained. A total of 288 reinforced concrete cubes will be arranged within it.”

"The concrete containers are positioned in a specific order. Once the cell is filled, any remaining space is filled with fine granular material, and the top slab is then constructed.”

There is still no exact date for when waste storage will commence, as additional preparatory stages remain.

Borislav Stanimirov – Deputy Chair of the Nuclear Regulatory Agency:
“The start of operations will be a trial period, during which they will justify the duration of this trial. Only after that will they submit the full application, so it is very difficult to estimate whether this will occur in 2026 or 2027.”

After the first 22 cells are filled, an additional 44 cells will be built in two further phases. These will be sufficient to support the operation of Kozloduy NPP even after the construction of the new Units 7 and 8. Once the repository is filled, it will be permanently sealed, with the first 300 years under strict control.

One source of radioactive waste comes from the decommissioning of the smaller Units 1–4 at Kozloduy NPP. These activities are carried out by the State Enterprise for Radioactive Waste under the supervision of the Nuclear Regulatory Agency.

Nikolay Grozev – Director of a Department at the Nuclear Regulatory Agency:
“The Chairman has issued a permit for the phased removal of 20 steam generators, after which a temporary facility will be built for their dismantling. The metal obtained will be gradually removed from regulatory control.”

Bulgaria has not yet decided what to do with high-level waste, such as spent nuclear fuel. Between 1996 and 2022, this fuel was exported to Russia for reprocessing and then returned to Bulgaria. Since the beginning of the war in Ukraine, spent fuel has been stored at the Kozloduy nuclear plant.

Nikolay Grozev:
“Kozloduy NPP has sufficient space to store spent fuel, and methods for its phased transfer are already being explored. From a radiological and nuclear safety perspective, the fuel is secure and poses no danger.”

The country still needs to decide whether to pursue reprocessing of spent nuclear fuel in the future, with discussions ongoing with France, or whether it will opt for permanent disposal.