This constitutes the first time that Rosenergoatom, which runs all of Russia’s 10 nuclear power plants, was ever slapped with a back tax claim. Most of the claims incurred by the corporation are related to profit tax payment, the paper said.

According to tax authorities, the nuclear power giant failed to include over 4.72 billion rubles ($197 million) in revenue from electricity sales on the federal wholesale electricity market in its financial statements for 2004-2005, underrating its profit tax by 1.133 billion rubles ($47 million).

The profit tax was underrated due to "price imbalances on the federal wholesale electric power market – a difference in tariffs set by the Federal Tax Service for electricity sellers and buyers," Kommersant said.

According to the paper, Rosenergoatom applied on April 10th to a Moscow arbitration court to challenge the tax authorities’ decision.

The press office of Rosenergoatom on Monday declined to comment on the company’s decision to challenge the tax claim, saying the nuclear power corporation had only just sent a complaint to the Federal Tax Service on March 11th.

"The enforcement of this decision has been suspended," the paper quoted the press office as saying.