Top 10 nuclear power facts

Most American aircraft carriers are powered by two reactors. The only exception was the early-constructed USS Enterprise, having an eight-reactor propulsion design, with each A2W reactor taking the place of one of the conventional boilers in earlier constructions. Enterprise was meant to be the first of a class of six, but construction costs ballooned and the remaining vessels were never laid down. The design was replaced by two-reactor Nimitz class.

Australia is practically the only developed country not using electricity (indigenous or imported) from nuclear energy. Australia's abundance of cheap coal, conveniently located to population centers, has ruled nuclear energy out of contention on economic grounds. There are nuclear power plants on all other continents, including South America (Brazil, Argentina) and Africa (South Africa).

Depleted uranium is 1.67 times as dense as lead, 84% as dense as osmium or iridium, which are the densest known substances under standard (i.e., Earth-surface) pressures. Consequently a depleted uranium projectile of given mass has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper (armor-piercing) penetration due to a higher pressure at point of impact.

Heavy water contains deuterium instead of common hydrogen-1. In its pure form it has a density about 11% greater than water, but otherwise, it is physically and chemically similar. It is not radioactive. Because of greater density and stronger hydrogen-oxygen bonds, its behaviour is slightly different in some biochemical reactions. It may be toxic, but only when a large fraction of water (> 50%) in higher organisms is replaced by heavy water.

Nuclear reactor requires no oxygen for combustion and emits no exhaust gas. It gives the submarine the ability to operate submerged at high speeds, for unlimited periods, dependent only on the endurance of its crew. Nuclear power revolutionized the submarine, finally making it a true "underwater" vessel, rather than a "submersible" craft.

By 1990 there were more nuclear reactors powering ships (mostly military) than there were generating electric power in commercial power plants worldwide (however, marine reactors are much smaller). Many of these submarines and other vessels were decommissioned in the 1990s.

Italy is the only G8 country without its own nuclear power plants, having closed its last reactors in 1990. Italy relies heavily on imports and is the world's largest net importer of electricity, mostly from French nuclear power stations. The next nuclear-free economy on the European GDP list is Poland.

The present situation is due to the French government deciding in 1974, just after the first oil shock, to expand rapidly the country's nuclear power capacity. This decision was taken in the context of France having substantial heavy engineering expertise but few indigenous energy resources.

Low carbon dioxide emission in France is a result of large investments in nuclear technology. Most electricity produced by France is generated by 59 nuclear power plants. As a side-effect renewable energies are having difficulty taking off.

Lake Karachay is a small lake in central Russia. It is often referred to as the most polluted site on earth. Containing just one square mile of water, the lake formed a dumping ground for nuclear waste by for around 12 years.High level radioactive waste makes up almost the entire lake-bed to a depth of around 3.4 meters. Some areas surrounding the lake have radiation measurements of around 6 Sv/hour, which is enough to give a lethal dose to a human in as little as 30 minutes¹.