The cost to repair and modernize the Yekaterinburg, a Russian nuclear submarine damaged by fire late last December, could total 900 million rubles ($30 million), a representative of United Shipbuilding Corporation said on Monday.

“Preliminary costs of repairs and modernization of the Yekaterinburg nuclear powered submarine are estimated between 600 million and 900 million rubles, depending on the price of the instruments and mechanisms that will be installed in the new hydro acoustic complex,” the USC representative said.

Some media reports previously said the costs would exceed 1 billion rubles but Deputy Prime Minister Dmitry Rogozin denied the reports.

Rogozin said the submarine would be repaired and re-enter service in summer 2014.

On December 29, the outer hull of the Yekaterinburg, a Delta-class nuclear submarine, caught fire during repairs at a shipyard in northwest Russia's Murmansk Region. Seven crewmembers and two responders were injured as they battled the fire, which was put out the following day.

There was no radiation leak because the reactors had been shut down before repairs began.

The submarine’s hydro acoustic system was disabled by the fire and will need to be replaced before it is brought back into service.

Delta-class submarines have an outer skin of anechoic rubber, designed to absorb sound from sonars to make the boat harder to detect, that can burn in a dry environment. The boat has a double hull of thick steel, however, which would protect its interior from external fire.

The repairs are scheduled to start this summer.