North Pole Since 2002, the Russians have also annually established a base, Barneo, close to the Pole. This operates for a few weeks during early spring. Studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage, with timescales varying from 2016 to the late 21st century or later. The sea depth at the North Pole has been measured at by the Russian Mir submersible in 2007 and at 4,087 m (13,410 ft) by USS "Nautilus" in 1958. The nearest land is usually said to be Kaffeklubben Island, off the northern coast of Greenland about
Nuclear submarine reactor pump (used to circulate reactor coolant), also creates noise, as opposed to a conventional submarine, which can move about on almost silent electric motors. Some of the most serious nuclear and radiation accidents by death toll in the world have involved nuclear submarine mishaps. To date, all of these were units of the former Soviet Union. Reactor accidents that resulted in core damage and release of radioactivity from nuclear-powered submarines include: Nuclear submarine A nuclear submarine is a submarine powered by a nuclear reactor. The performance advantages of nuclear submarines over "conventional" (typically diesel-electric) submarines are considerable. Nuclear propulsion,