Nuclear Energy in Bulgaria (04.05.2023)

• In Bulgaria, two nuclear power plants (NPPs) are currently in operation at Kozloduy, and another unit is to be built there.

• NuScale Power's majority shareholder has entered into an agreement with Bulgaria's state-owned utility for a potential deployment of Small Modular Reactors (SMRs).


Status quo of electricity generation

In Bulgaria, the Kozloduy NPP operates two reactor units of the Russian VVER-1000 (V-320) type, each with an electrical output of 1,000 megawatts (MW): Kozloduy 5 and 6. Units 1 to 4 (VVER-440/230) were shut down in 2002 and 2006, respectively, in the context of Bulgaria's accession to the European Union; Units 5 and 6 underwent extensive modernisation by 2007.

Electricity Mix Bulgaria
Strommix Bulgarien

The NPP covers just over a third of Bulgaria's electricity demand; lignite-fired power plants supply around 40 per cent, while renewable energies contribute around 15 per cent to the electricity supply (as of 2019). Bulgaria has so far been heavily dependent on natural gas supplies from Russia, with around 90 percent of imported natural gas coming from there. However, natural gas contributes only 5 per cent to electricity generation.

In earlier years, Bulgaria exported a significant share of domestically generated electricity. Although this share has decreased, Bulgaria is still a net exporter of electrical energy (almost 6 terawatt hours in 2019).

Political and legal framework

The current Bulgarian government attaches great importance to nuclear power for the country's future energy supply. In the negotiations on the "EU taxonomy", it advocated that both nuclear power and electricity generation from gas be classified as sustainable in the sense of the taxonomy. New-build plans have been pursued for many years (see paragraph below), but have so far failed, in particular due to a lack of funding. State funding for new construction projects is still ruled out.

In addition, the government is seeking an extension of the operating lives of the two units still in operation at Kozloduy. After a 10-year extension of the operating lives, the two reactors may still be operated until 2027 and 2028 respectively; the operator had already considered an extension until 2047 possible in the context of the licensing procedure at the time.

Current plans and projects

Large NPPs. At the Belene site, construction of a Russian VVER-1000 (V-320) had already begun in 1987. However, the project was terminated in 1991 due to lack of financing, after a significant part of the technical equipment had already been delivered and some of the construction work had been done. In 2008, a new contract was concluded for the construction of two VVER-1000 (AES 92) reactor units, on the basis of which construction work was again carried out in the following years and technical equipment (including two reactor pressure vessels) was delivered on a larger scale. Due to difficulties with financing and changing governments, this project also came to a standstill in 2012. In 2013, the then government announced a halt to the project, but the next government intended to re-examine it. In June 2016, the International Court of Arbitration awarded 620 million euros to Atomstroyexport for deliveries already made. In mid-2018, the Bulgarian parliament voted to resume the project on the government's proposal; by mid-2020, several companies or consortia had expressed interest in investing in or building the plant. A formal decision on construction at the Belene site has not yet been made.

NPP Units in Bulgaria
Landkarte Bulgarien

Instead, parliament adopted a plan to build a further reactor unit at the Kozloduy site in early 2021. For this site, too, further construction had already been considered since the early 2010s. The first agreements on the construction of an AP 1000 were concluded with the US company Westinghouse in 2014, with the initial consideration being to use some of the technical equipment originally supplied for Belene if possible. Problems with financing also delayed this project for several years. Finally, in 2020, an environmental impact assessment for the Kozloduy site was completed and the Bulgarian government committed to the construction of an AP 1000.

The Bulgarian Ministry of Energy indicated at the end of March 2023 that pre-project study agreements would be signed with Westinghouse for two AP-1000s at the Kozloduy site and with EdF for the completion of the two VVER-1000 units at Belene. A few weeks earlier, Westinghouse had signed a memorandum of understanding to initiate planning for the possible use of one or two of its AP-1000 reactors at the Kozloduy site. Already in early 2023, the Ministry of Energy had presented an energy strategy for Bulgaria for the period 2023 to 2053, which included plans for two new reactors at the Kozloduy site and two at the Belene site.

SMR. The US Flour company, which holds a majority stake in NuScale Power, has concluded an agreement with the state-owned utility (Bulgarian Energy Holding) on the potential use of the NuScale SMR in 2021. Both the construction of such plants at the Kozloduy NPP site and their use for a so-called repowering of coal-fired power plants, i.e. the replacement of the latter using the already existing infrastructure (especially the grid connection), are to be examined.

Research reactor

At the Institute for Nuclear Research and Nuclear Power of the Bulgarian Academy of Sciences in Sofia, an IRT-2000 research reactor was operated from 1961 until 2008. The pool-type reactor was built by the Russian Kurchatov Institute and originally operated with highly enriched uranium (36 per cent enrichment level). In 2008, the reactor was shut down to be rebuilt with a modified design. Due to a lack of funding, the project has not been completed to date.