Bulgaria’s nuclear power plant at Kozloduy was built according to Soviet design and comprises six VVER type-reactors. The Western European Nuclear Regulatory Association, and other experts, concluded that units 1-4 (VVER 440-230) could not achieve acceptable safety levels with economically viable investment. In view of Bulgaria's accession to the European Union, the Bulgarian government agreed to close down units 1-4 of the Kozloduy nuclear power plant (KNPP). Units 1 and 2 were shut down in 2002 and units 3 and 4 in 2006.
The Kozloduy International Decommissioning Support Fund (KIDSF), administered by the EBRD was established in June 2001 as an assistance programme of the European Commission and other European contributors to help the Bulgarian government cope with the early closure and decommissioning of the four units and consequential measures required to be undertaken in the energy sector.
KIDSF operates on the basis of a Framework Agreement between the EBRD and the Bulgarian Government, ratified by the Bulgarian Parliament. Some €1 billion has been contributed, largely by the European Commission, as well as by Austria, Belgium, Denmark, France, Greece, Ireland, the Netherlands, Spain, Switzerland and the United Kingdom.
The KIDSF finances and co-finances investment projects for two main purposes:
- To support the decommissioning of KNPP units 1-4.
- To address the consequences in the energy sector related to the closure of units 1-4.
A key facility, required for the safe decommissioning of KNPP units 1 to 4 and funded by KIDSF, is the dry spent nuclear fuel storage facility, in operation since January 2016 and used for interim storage of the spent fuel from the decommissioned reactors for a period of over 50 years.
Other KIDSF funded projects provide the supporting infrastructure for dismantling, handling, sorting of power plant equipment, characterization, treatment and storage of historical radioactive waste and radioactive waste generated during the decommissioning process. In a breakthrough in the treatment and conditioning of solid radioactive waste with high volume reduction factor, a plasma melting plant commenced operation at Kozloduy in 2018. The plant will process up to 250 tonnes of radioactive waste per year, significantly reducing its volume. Metals, concrete debris, sand, inorganic granulates, insulation material, asbestos are melted and transformed into a chemically inert and amorphous glassy slag. Liquids and organic materials are vaporised.
The size reduction and decontamination workshop successfully passed active integrated tests in December 2017; now ensuring the essential stream for the treatment of contaminated materials dismantled from the turbine hall and controlled area. The processing capacity of the facility is up to 4 tonnes of materials per day.
KIDSF also supports the construction of a near‑surface repository close to the Kozloduy site, accepting low- and intermediate-level radioactive waste from KNPP units 1 to 4 decommissioning process. The planning phase, including site selection, geological, hydrological and engineering-geological assessments, safety and environmental impact assessments, design and site infrastructure preparation is complete. The facility construction began in 2017 and its operation will start in 2021.
The transfer of responsibility from KNPP to the State Enterprise Radioactive Waste (SERAW) for the decommissioning of Kozloduy NPP Units 1-4, including the hand-over of projects and transfer of personnel, has been a complex and time-consuming process which has now been successfully completed. SERAW has assumed ownership of all four units.
KIDSF supports implementation of the decommissioning activities executed by SERAW personnel. The continued use of personnel transferred from Kozloduy NPP is a cost-effective approach, making best use of the in-house knowledge and skills gained during operation and previous decommissioning activities. Tasks include dismantling, decontamination, free release and waste management in accordance with the decommissioning plan and schedule.
Dismantling of equipment in Units 1 to 4 Turbine Halls is on track for completion in August 2019.
Energy sector projects
KIDSF funded and co-funded energy efficiency measures in line with the National Energy Strategy to mitigate the consequences of decommissioning of KNPP Units 1-4. The programme includes:
- Rehabilitation of the district heating network in Sofia
- New electricity meters in private households
- Energy efficiency improvements in public buildings
- Rehabilitation of municipal street lighting
- Energy efficiency and renewable energy credit line facilities for residential and industrial sectors
- Environmental and energy efficiency improvements at the coal fired Maritza East power plant
- Upgrade of the heavy industrial mining equipment of Maritza East Mines
- Upgrade and extension of the national electricity distribution and transmission systems
- Rehabilitation of hydro power plants
- Support for residential sector gasification
- Construction of high pressure gas pipelines
The measures in the energy sector have significantly compensated for the loss of operating capacity and reduced emissions. The assessment of the overall results, completed in April 2018, established that energy savings in the assessed projects total 2,077,883 MWh/year, equivalent to 310 MW of effective electricity generating capacity and an annual decrease of CO2 emissions by 1,380,752 t.
The assessment results confirm that the objectives and priority areas of KIDSF grant support for ensuring long-term energy supply security for the end-consumers at affordable level and for improving the energy sector efficiency after the shutdown of Kozloduy NPP units 1-4 have been successfully achieved.
Additional effects are improved working and living conditions in more than 340 public buildings, i.e. hospitals, kindergartens and schools, and for thousands of households all over Bulgaria.
KIDSF support is now focused on the decommissioning programme and will not be used for any new energy sector projects.