The Kozloduy NPP is the only nuclear power plant in Bulgaria.

Bulgaria, one of the countries hardest hit by the Russia-Ukraine gas dispute, is threatening to restart two nuclear reactors that were shut down over safety concerns two year ago. Slovakia has threatened to do the same at its Bohunice power plant if gas flows don’t resume soon.

The push by Bulgaria and Slovakia highlights the EU’s need to diversify its gas supply routes. “Preparations … must begin immediately,” said Bulgarian President Georgi Purvanov shortly after Russia cut supplies to Europe. He was referring to reactors three and four of the Kozloduy power plant. The closure of the reactors was a prerequisite to Bulgaria’s entry into the EU.

Puranov recently said that under the treaty that allowed Bulgaria to join the EU, his country has “the right to resume the operation of the two reactors in a critical situation, and a more critical situation is hardly possible,” he was quoted as saying by the semi-official Bulgarian News Agency. “If the situation does not normalize,” he added referring to Russian gas cuts, “I expect our European partners to show understanding and not to object to such a move," Purvanov said.

But the possibility of actually restarting the reactors appears slim. It would take at least one month to do so and would require the EU’s permission, a process that would be lengthy, according to Ferran Terradelas, spokesman of the EU Energy Commission.

But neither Bulgaria nor Slovakia have made official requests and those requests appear more remote now that Russia has agreed to restart gas supplies. Bulgaria would also face angry opposition in Brussels. “It has never happened,” Terradelas said. “Bulgaria’s problem is about gas provisioning and it won’t be solved by restarting the reactors. We are not considering it at the moment, at all. This is a closed issue for us.”

Bulgaria relies almost entirely on Gazprom subsidiaries for its gas. It has survived on electric heaters, as have many in Southern Europe. The country still exports electricity thanks to the two remaining reactors of the six that once ran in Kozloduy. Before they were shuttered, the two older reactors at the site were so dodgy that they were included in the list of the ten most dangerous reactors in the world. Closed in 2006, the two 440-megawatt reactors are from the Soviet era. The plant, which borders Romania, still has two 1,000 MW reactors operating.

Bulgaria’s public stance though illustrates just how serious Eastern and Southern European countries – who are the most vulnerable to gas cuts originating in Ukraine -- are eager to diversify their gas supplies.

Europe gets 25 percent of its gas from Russia, 80 percent of which transits through Ukraine. Most of the continent has been hit by the cuts, with 10 countries dependant on Russia for at least 60 percent of their gas. Moscow’s gas strangle is only expected to tighten into the future as Europe’s demand continues to grow.

Companies and officials called for quick agreement to build the Nord Stream and South Stream pipelines, both Russian-led pipeline projects, and Nabucco, headed by an Austrian-led European consortium. And not surprisingly, Iran has offered to pump more gas to Turkey to make up for the Russian cuts.