The meaning of the word nuclear weapon, is a weapon that has a nuclear warhead on it.
Yes, a nuclear explosion is considered a man-made disaster when it results from human actions, such as the detonation of a nuclear weapon. While nuclear reactions occur naturally in the universe, the controlled use of nuclear fission or fusion for weaponry is a product of human technology and decision-making. Additionally, accidents at nuclear power plants can also lead to catastrophic events, further categorizing them as man-made disasters.
You can count them yourself in the related link on The Nuclear Weapon ArchiveA Guide to Nuclear Weapons
This nuclear weapon is called an atomic bomb or a nuclear bomb
Nuclear weapon detonations
If by "bomb" you mean a conventional explosive weapon, then the nuclear weapon is more powerful.
nuclear chemicals such as plutonium
No. LLNL even tested several Uranium-Hydride bombs in the 1950s. Even though their computer models said the devices should explode, none gave a nuclear yield. One could use the waste from the reactor as a Radiological Weapon, but the reactor itself is not useful as a weapon.
NO
no
plutonium + weapon
the first nuclear weapon was issued in WW2 created by the americans in a chicargo squash court