Russia announced plans Wednesday to send an atomic-powered icebreaker that developed a nuclear leak earlier this month back out to sea after conducting quick repairs on the reactor.

The 23-year-old Taimyr successfully docked at its home port of Murmansk near the Norwegian border on Wednesday after using back-up diesel engines to make its way back from the Kara Sea in the Arctic.

Rosatomflot nuclear fleet chief Vyacheslav Ruksha said the vessel remained safe and attributed the radiation spill to a micro-fracture that resulted in the leakage of 6,000 litres of nuclear reactor coolant.

"We were lucky because this situation developed at the end of the voyage. But we had to change our plans because it was due to set sail for the Arctic in June," RIA Novosti quoted Ruksha as telling a Murmansk press briefing.

"Now the icebreaker will undergo repairs, and no one knows how long they will last. Practice shows they could stretch between two weeks and two months."

He also confirmed that this was the second such leak to affect the 21,000-tonne craft in a year.

The Taimyr is one of two nuclear icebreakers built for the Soviet Union by Finland in the late 1980s.

The US-based GlobalSecurity.org research organisation said the two Finnish ships were "originally designed for 100,000 hours of reactor life, but this was extended first to 150,000, then to 175,000."