May 06, 2011 8:10AM

RUSSIA have launched an urgent rescue mission after one of its atomic-powered icebreakers developed a nuclear leak in the frozen seas of the Arctic and was forced to abandon its mission.

The Rosatomflot nuclear fleet said in a statement that an "insignificant increase in activity" had been detected on board its 21,000-tonne Taimyr icebreaker.

But the incident was serious enough to force the vessel to abandon its mission and begin a five-day journey back to its home port in the north-western city of Murmansk.

The agency also announced plans to shut down the reactor before the ship enters into port - a reversal of an initial statement saying that decision would be reached only if the situation got out of hand.

Officials stressed that their most immediate worry concerned the 23-year-old vessel's ability to navigate the rough icy sea of the Arctic.

"What we are most concerned about right now is movement along the waterways," the state-run RIA Novosti news agency quoted top Rosatomflot official Andrei Smirnov as saying.

The fleet official said another icebreaker was being dispatched to the region to help the Taimyr's journey back to port. But it was not clear how far it remained from the stricken craft.

The incident was reported in the Kara Sea - a part of the Arctic Ocean about 2000km east of Norway's border.

The Taimyr has a single 171-megawatt reactor that generates about one-third the energy of the Fukushima 1 reactor affected by the Japanese earthquake and tsunami disaster in March.

[link to www.theaustralian.com.au]