Employees stand in front of the second power unit of the Khmelnytskyi Nuclear Power Plant, amid Russia's attack on Ukraine, near the town of Netishyn, in Khmelnytskyi region, Ukraine August 7, 2024.

Ukraine's parliament on Tuesday passed a law that allows the state nuclear power operator to buy two Soviet-designed nuclear reactors from Bulgaria for Ukraine's Khmelnytskyi power plant, lawmakers said.

Ukraine had planned last June to sign a deal to buy two nuclear reactor bodies from Bulgaria to compensate for the loss of the Russian-occupied Zaporizhzhia nuclear power plant, which has six reactors, but was prevented by the absence of a law to allow the purchase.

The law does not specify the amount of the contract.

Ukrainian officials have said Bulgaria had previously put the price of the two reactors at $600 million.

A number of politicians objected to the law, saying they opposed the purchase of Russian equipment at a non-transparent price in the context of the war with Russia.

But the law was nevertheless passed as Ukrainian officials said the purchase would make it possible to launch the first of the two new units in two to three years. That would significantly reduce power shortages in the country, where Russian missile and drone attacks have destroyed energy infrastructure.

President Volodymyr Zelenskiy said parliamentary approval for the reactors, with a capacity of more than two gigawatts, was a "major step" in ensuring Ukraine's energy security.

"Our completed reactors will allow Ukraine to get through the winter months without the need for imports," he said in his nightly video address.

Opposition to the move, he said, was led by those who had a vested interest in "more expensive energy sources".

And the president said expanding nuclear capacity would help Ukraine in special projects, including a proposed plan by U.S. President Donald Trump to develop rare earths.

"Ukraine will now be able to speak more confidently, knowing that it will have a significant additional source of power in the future," Zelenskiy said.

Since the loss of Zaporizhzhia, Ukraine has relied on nuclear power from three operating power plants in the country, with nine reactors in total, including two in operation at the Khmelnytskyi plant.

Construction of the third and fourth reactors at Khmelnytskyi began in the 1980s, but was halted because of the Chornobyl nuclear disaster.

Nuclear electricity accounts for about 60% of Ukraine's power needs.