No Risk from Leaking Russian Nuclear Submarine Wreck

Published Jul 10, 2019 8:44 PM by The Maritime Executive

Researchers have documented a leak from the wreck of the Soviet nuclear submarine, Komsomolets, noting it poses no risk to people or fish.

The Russian submarine sank in 1989 and is currently resting on the floor of the Barents Sea, one mile deep, with its nuclear reactor and two nuclear warheads still on board. She sank after a fire broke out in the aft engineering compartment on her first operational patrol. The Komsomolets was able to surface after the fire started and remained afloat for approximately five hours before sinking. Of the 42 crewmembers who died, only four were killed by the fire and smoke, while 34 died of hypothermia and drowning in the frigid waters while awaiting rescue.

As part of an on-going monitoring program, the Norwegian researchers took several samples in and around a ventilation duct on the wreck and found they contained levels of radioactive cesium levels around 800,000 times higher than normally found in the Norwegian Sea. They were around 100 Bq per liter, as opposed to around 0.001 Bq per liter elsewhere in the Norwegian Sea. The permitted limit for radioactive cesium in food products after the Chernobyl accident in 1986, was set to 600 Bq/kg by Norwegian authorities.

“Over the past few days we have also taken samples a few meters above the duct. We didn’t find any measurable levels of radioactive cesium there, unlike in the duct itself”, says Justin Gwynn, a researcher at the Norwegian Radiation and Nuclear Safety Authority (DSA).

Just before taking the first sample that gave a high reading, researchers noticed a “cloud” rising up from the duct. A “cloud” was also seen rising from a grille nearby, where the researchers again measured high levels. “It looks very dramatic on video, and it’s definitely interesting, but we don’t really know what we’re seeing and why this phenomenon occurs. It’s something we want to find out more about”, says Gwynn. 

The Institute of Marine Research (IMR) and DSA have performed joint annual surveys of the wreck since the 1990s. This year’s survey is the most thorough investigation of Komsomolets ever performed by Norwegian scientists.

The IMR has previously modeled what would happen if all of the radioactive cesium in the wreck were to leak out at once. The conclusion was that the impact on fish in the Barents Sea would be negligible. 

Both the IMR and DSA still believe that it is vital to continue monitoring the only known source of radioactive pollution in Norwegian waters.