A nuclear-powered icebreaker is an icebreaker with an onboard nuclear power plant that produces power for the vessel's propulsion system. As of 2022[update], Russia is the only country that builds and operates nuclear-powered icebreakers, having built a number of such vessels to aid shipping along the Northern Sea Route since the Soviet times. Nuclear-powered icebreakers are much more powerful than their diesel-powered counterparts. Although nuclear propulsion is expensive to install and maintain, very heavy fuel demands, limitations on range, and difficulty refueling in the Arctic region can make diesel vessels less practical and less economical overall for these ice-breaking duties.
During the winter, the ice along the Northern Sea Route varies in thickness from 1.2 to 2.0 m (3.9 to 6.6 ft). The ice in central parts of the Arctic Ocean is on average 2.5 m (8.2 ft) thick. Nuclear-powered icebreakers can force through this ice at speeds up to 10 kn (19 km/h; 12 mph). In ice-free waters, the maximum speed of the nuclear-powered icebreakers is as much as 21 kn (39 km/h; 24 mph).