Construction of the world's largest civilian ice breaker propelled by nuclear reactors is underway in Russia.Rosatom subsidiary Rosatomflot announced last week it has begun building the 569-foot-long ship at the Baltic Shipyard in St. Petersburg. In its announcement, the company claimed the ship will not only be the largest and most powerful ice-breaking vessel in the world, but will also allow shipping traffic in arctic routes year-round. The Barents Observer reported that tenders for two additional ships of the same design have been announced.The $1.47 billion craft will rely on two RITM-200 pressurized water reactors. Producing 55 MWe each, they are similar to reactors Russia is considering for floating nuclear power plants, according to the World Nuclear Association. They run on a seven-year fueling cycle over a 40-year design life. State-owned Rosatom, which controls the country's nuclear power enterprise, acquired Atomflot from the Russian transport ministry in 2008. Atomflot has operated nuclear-powered ice breakers in the arctic since 1959 and last commissioned a nuclear ship in 2007.