Sunken nuclear submarines

Submarine (GettyImages)A total of eight nuclear submarines are known to have been lost at sea in the past decades. Out of these eight, two belong to the United States, four to the former Soviet Union and the final two to the modern Russian Navy.

The probability of radiation leaks is rather low. The reactors of the US vessels are shielded, fuel rods are encased in an alloy that corrodes at extremely little rate. And even in the unlikely scenario, that the shielding of one of the reactors were to be damaged, the alloy should keep seawater away even for centuries, a time during which most of the radioactive material will be decayed.

The named Soviet and Russian vessels and their reactors have similar safety features, and nuclear-tipped torpedoes also have similar protective mechanisms in place.

USA:

USS Thresher (April 10, 1963)

USS Scorpion (May 22, 1968)

Former Soviet Union

K8 (April 11, 1970)

K27 (May 24, 1968)

K278 (April 7, 1989)

K219 (October 3, 1986)

Russian Federation

K141 (August 12, 2000)

K159 (August 28, 2003)

It is at this point difficult to assess, if the sunken nuclear submarines will ever develop into a substantial environmental threat. Despite corrosion occuring, it happens at such reduced rates that the materials inside have most likely stopped radiating at the time leakages occur.