Countries want them, countries make the laws.
How to make nuclear bombs was solved over half a century ago.
It can.
Nuclear bombs are so powerful, and release so much radioactive fallout, that any large-scale use of nuclear bombs would kill everbody and make the world uninhabitable.
yes
plutonium
The nuclear material used to make the bombs was from Oak Ridge TN
nuclear bomb = plutonium + weapon
Generally, no. But nations capable of making nuclear power plants may be able to extend the technology to make weapons.
You think to applications of nuclear physics.
No place, we have not yet determined how to make a fusion reactor. Only fusion bombs.
No, it is perfectly legal as long as it is used on your own property.