That depends on how they are used, their yields, and many other variables. With the information specified in your question, no definite answer can be given.
Use of nuclear weapons in wartime.
Heat is the obvious choice for controlled use of nuclear energy. In a weapon you also want a blast effect to destroy buildings etc.
plutonium + weapon
The meaning of the word nuclear weapon, is a weapon that has a nuclear warhead on it.
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, 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.
This nuclear weapon is called an atomic bomb or a nuclear bomb
Truman in WW2 on Japan.
Harry Truman - August of 1945
US
The roman army did not use nuclear weapons.
nuclear bomb