Nobody, the US was the first country to work out how to actually make nuclear weapons.
USSR
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. Canada gave it's last nuclear weapon to the United States in the mid 1980's.
The meaning of the word nuclear weapon, is a weapon that has a nuclear warhead on it.
The US performed the first nuclear weapon test on July 16, 1945.
End of WW2.
never, most of their nuclear weapon activity was for propaganda purposes.
US
They were pretty nervous...................
Manhattan project
no one can have a nucular weapon except the government and such
no