I think that North Korea is one and an other is china.
Iran
iraq
A nuclear weapon is used to prevent being threatened by other nuclear countries. Say, for example, France got rid of all of it's nuclear weapons, tiny countries that had a nuclear weapon would be able to bully them into accepting bad deals or presurring them into not reacting when things happen. Most countries in the world would probably like to dispose of their nuclear weapons but they can not due to the fact of little countries with problems that will keep them would be able to threaten them and hold the world by it's throat.
they already are
No, a nuclear explosion on a nuclear power plant would not cause the explosion radius to increase. The explosion radius would be determined by the yield of the nuclear weapon itself, not by the presence of the power plant.
No, a single nuclear weapon is not powerful enough to blow up an entire continent. The destructive power of a nuclear weapon is concentrated in a relatively small area known as the blast radius. The impact would be devastating locally, but the effect would not extend to an entire continent.
The amount of radiation produced by a nuclear weapon can vary depending on its size and yield. However, a single detonation of a nuclear weapon can produce tens of thousands to millions of rads within the immediate vicinity of ground zero. This level of radiation exposure can be lethal to humans and cause widespread health effects.
The term precision nuclear weapon may be a misnomer, but it is generally used to describe a low yield nuclear weapon (perhaps a few kilotons) that can be delivered with great accuracy on a specific target.The idea is to use this device, which is very small compared to an equivalent conventional weapon, in applications like busting deeply buried bunkers or other large below ground installations. Using a nuclear weapon in this type of application would gain a more assured result than the use of conventional explosives. The catch is that if you have this wonderfully effective weapon with all these superior characteristics, you may be tempted to use it.It may or may not be helpful to compare the precision nuclear weapon to what we call a tactical nuclear weapon. This nuclear device has a low yield (about a kiloton or so) that was designed to be delivered by conventional large-bore cannon or a small missile. The limited blast could be directed in a way that it could destroy something like a concentration of armored vehicles or troops that it would be difficult to do with conventional explosives. Consider that a small tactical nuclear weapon that could fit inside a 155 mm cannon shell would do damage that a thousand tons of TNT would be needed to accomplish.
This would be plutonium in modern nuclear weapons. Another actinide common in nuclear weapons is uranium. Nowadays this is usually found in the secondary of the weapon. The Little Boy weapon used against Hiroshima used uranium as the fissile material. This was a single stage weapon. A few other weapons also used uranium as the primary nuclear explosive.
Basically, a conventional bomb uses a chemical explosive as the source of its destructive power. A nuclear weapon uses nuclear material to create an explosion. A nuclear explosion is much larger, and also emits ionizing radiation. A chemical weapon does not emit any radiation. A nuclear weapon's yield is measured in Kilotons (thousand tons). In very simplified terms, this means that a nuclear weapon with a 475 kiloton yield produces an explosion comparable to 475,000 tons of TNT (TNT is a chemical explosive). That's A LOT of TNT and it would take up a bit of space. A nuclear weapon with this yield may only be a few feet long and a foot wide, and the actual nuclear material may be the size of a grapefruit.
The actual answer may surprise even you: ID 1667019371. If Iran ever used a nuclear weapon on any country, let alone Israel, Iran would be destroyed.
The yield of a nuclear weapon is its energy release, usually expressed in the weight of TNT that would release the same energy (e.g. kilotons, megatons). It depends strongly on type of bomb (fission or fusion) and many design details.