Sunken soviet sub leaks radiation into arctic 35 years after cold war tragedy

At 1 680 m beneath the Norwegian Sea, the Komsomolets is corroding faster than anyone predicted. Norwegian probes just found radioactive caesium venting from its reactor compartment, proof that the Cold War’s deepest nuclear wreck is no longer safely entombed.

The titanium-hulled attack boat sank in 1989 after a short-circuit sparked a fire that killed 42 of 69 sailors. It took with it a 190 MW pressurised-water reactor and two nuclear-tipped torpedoes. Moscow sealed the hull in 1995, declared the site monitored, and moved on. The sea did not cooperate.

Radiation is creeping out, drop by drop

Using the remotely-operated vehicle Ægir 6000, researchers from the Institute of Marine Research sampled a ventilation pipe that once kept the reactor cool. The reading: 800 000 becquerels per litre of caesium-137, a million times above background. “That number is climbing,” says expedition leader Justin Gwynn. “The fuel is literally dissolving.”

Plutonium from the torpedoes remains locked inside their 1995 casings—for now. The worry is mechanical collapse: the hull is pitted, bulkheads sag, and every winter storm accelerates metal fatigue. When the torpedo compartment finally buckles, 2 kg of weapons-grade plutonium will hit a current that feeds directly into Norwegian salmon fjords.

Oslo has asked Moscow for joint recovery funds since 2019. The Kremlin cites state secrecy and offers only annual sonar sweeps. Meanwhile, NATO submarine traffic above the wreck has doubled, raising the spectre of a collision that could rupture the site in minutes.

The bill for doing nothing keeps rising

Raising the Komsomolets would cost an estimated €1.2 billion and require robotic cutting inside a cloud of silt. Leaving it untouched means gambling on a future leak that could shut down fisheries worth €4 billion a year. “We’re past the point of monitoring,” says Hilde Elise Heldal, who led the 2023 survey. “Either we retrieve the fuel or we accept a slow-motion contamination event.”

Every other nuclear wreck—from the 1968 Scorpion off Azores to the 1986 K-219 in the Atlantic—has shown the same pattern: first a trickle, then a surge. The Komsomolets is simply the next in line, 180 km from the nearest inhabited island, ticking louder each season.