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.
Use of nuclear weapons in wartime.
plutonium + weapon
The answer is impossible: we can use uranium in weapons but we can also use uranium in another very useful applications; it is a choice: aggressive countries as United States, United Kingdom, Israel, Russia, etc. can use nuclear weapons as a threat against the other countries.
Plutonium is the core of a nuclear weapon; the nuclear fission release an enormous quantity of energy and radiations.
The roman army did not use nuclear weapons.
US
nuclear bomb
Harry Truman - August of 1945
Truman in WW2 on Japan.
For somehow, US invented this weapon and if Chinese dared to do this, the first country gonna attack back is US. They will be doomed if there is war between the Chinese ans US.
The only wartime use of a Nuclear weapon was the ending of World War II with the American Nuclear Strikes on Hiroshima and Nagasaki.
The United States of America used the first nuclear weapon in war, when they bombed Japan.