Bulgaria has signed a €72m ($80m) agreement with a consortium comprising German Nukem Technologies (owned by Russia's AtomStroyExport) and four Bulgarian companies to build a radioactive waste repository for its Kozloduy NPP. The repository is expected start operations in 2021, according to Bulgaria’s Energy Ministry. The €72m allocated for construction of the first phase of the facility is a "significant" amount, said Energy Minister Nikolay Nikolov. The first stage of the project will include development of licensing documents for the facility's commissioning in accordance with national nuclear legislation.

The "near-surface trench type" repository will have a capacity of 138,200 cubic metres and will be located in the 3km "surveillance zone" of the Kozloduy plant, the Ministry said. The facility will consist of several concrete structures separated by the partitioned chambers and will be filled with radioactive waste over the next 60 years.

The project is to be funded by a grant from the Kozloduy International Decommissioning Support Fund, which is administered by the European Bank for Reconstruction and Development (EBRD).  Nikolov said the project will boost the process of decommissioning the shutdown units of the Kozloduy NPP. The State Enterprise Radioactive Waste  (SERAW) is responsible for the decommissioning of units 1-4 and the national radioactive waste disposal facility.

Bulgaria agreed to close units 1-4 as a condition for its accession to the European Union. All four units are V-230 model VVER-440 reactors, which the European Commission had earlier classified as non-upgradable. However, units 3 and 4 were of an improved design and closer to the later V-213 design than any others of their class. They were closed despite  several international studies verifying the safety of the units and a 2005 opinion poll showing 75% support for keeping them running. Kozloduy units 5 and 6 (VVER 1000/V-320s) continued to operate and are currently undergoing upgrading in preparation for life extension.