Bulgaria’s deputy prime minister and chairman of the co-ruling Bulgarian Socialist Party (BSP), Atanas Zafirov, said that Bulgaria needs to develop its nuclear energy capacities.

“We were adamant from the start that these reactors are not for sale. They are a key asset for Bulgaria – part of our energy security and economic independence,” said BSP leader Atanas Zafirov.

Ukraine sought the reactors to complete its Khmelnytskyi nuclear power plant. The proposed deal was valued at just over €600 million ($682 mn).

The two VVER-1000 reactors have been in storage near the Danube River. Bulgaria abandoned plans to use them at the Belene nuclear power plant. Instead, Bulgaria decided to build new units at Kozloduy NPP using American technology.

Ukraine’s parliament had already passed legislation approving the purchase. The reactors are compatible with Ukraine’s existing infrastructure.

In February 2025, GERB party leader Boyko Borissov had confirmed the sale. He predicted the BSP would not block the transaction. Borissov promoted the deal as financially beneficial for Bulgaria.

“We have a collective decision regarding the fate of the two reactors—they will not be sold. This is a decision supported by all coalition partners. I thank our partners for standing united behind this strategic choice,” Zafirov announced on 15 April.

Zafirov claims Bulgaria has the expertise and prepared site to build a second nuclear power plant. This assertion comes despite the government’s abandonment of the Belene project. That project cost over €1 billion with no results.

Ukrainian officials report they received no formal notification about Bulgaria’s reversal. “We learned about this decision from media reports,” a source at Ukraine’s energy ministry told Euractive. “We are seeking clarification through diplomatic channels.”

This setback reportedly may delay Ukraine’s plans to expand nuclear capacity.

“Ukraine needs these reactors to meet growing energy demands,” said Maria Tsvetanova, an energy consultant in Kyiv. “Finding alternative suppliers will be challenging in the current market.”

Nuclear power is critical for Ukraine’s energy security. It covers more than half of the country’s electricity consumption. Russian missile and drone attacks have severely damaged Ukraine’s thermal and hydroelectric generating capacity. This has forced periods of emergency shutdowns.

The Khmelnytskyi plant is one of three remaining operational nuclear stations in Ukraine-controlled territories. Ukraine aims to expand it to compensate for the loss of the Zaporizhzhia Nuclear Power Plant. The facility is currently under Russian occupation.

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