Norway has found a radiation level 800,000 times higher than normal at the wreck of a Russian navy submarine that sank in the Norwegian Sea in 1989.
A sample showed radioactive caesium leaking from a ventilation pipe in the Komsomolets. But researcher Hilde Elise Heldal said it was “not alarming”, as the Arctic water quickly diluted it.
The Soviet-era sub is also deep down, at 1,680m (5,512ft), and there are few fish in the area, she said.
A fire on board killed 42 sailors.
For the first time a Norwegian remotely-operated vehicle (ROV) examined and filmed the Komsomolets, on 7 July, revealing severe damage.
It is also known as K-278 in Russia, and it sank carrying two nuclear-tipped torpedoes. Its front section has six torpedo tubes, and the sub could also launch Granit cruise missiles.
The ROV revealed what looks like one of the sub’s torpedoes.
The news comes just over a week after fire swept through a Russian nuclear-powered submersible in the Barents Sea, killing 14 naval officers.