No. It is not illegal to build a nuclear device any more than it is illegal to say mix up ANFO or make a lockpick, provided you have the required permission to possess the materials and technology need for the job.
Simple creation and possession of something is not usually illegal, regardless of its possible uses, and nuclear devices are no different.
The meaning of the word nuclear weapon, is a weapon that has a nuclear warhead on it.
No, there is not imminent threat of Iran building this past summer, a National Intelligence Estimate on Iran's nuclear capabilities was released showing that Iran was 10 years away from building a nuclear weapon. This estimate represents a consensus among the U.S. intelligence agencies. Nuclear war or atomic war is war in which nuclear weapons are use.
This nuclear weapon is called an atomic bomb or a nuclear bomb
Nuclear weapon detonations
Iran is currently in the process of makes nuclear weapons although they say it is for friendly purposes but why are the making them for if it's for friendly purposes right?
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