The US tested nuclear weapons on its own territory including the deserts of the continental southwest US.
The new country that want to make nuclear weapons. And how to consult with they own weapons
India is already a nuclear power, and they have nuclear weapons on hand. They have already made the decision to "encourage" nuclear weapons, and presumably for increasing their own security.
Originally the USSR was assisting them with reactors and was promising to supply nuclear weapons if needed, so China would not have to develop their own. However the USSR withdrew from this agreement in 1959. This caused China to begin their own nuclear weapons project, culminating in their first test in 1964. So nobody assisted China to develop nuclear weapons. They did it on their own.
As far as I know nuclear weapons have never been traded between countries, so if a country has nuclear weapons it is due to their own science and technology, or to espionage activities to get the required knowledge. The other criterion is not to have signed up to the Non Proliferation Treaty, except for countries that had already developed weapons when the Treaty came into being.
No, Israel designed their own.
Most did their own independent development.
Nobody. There have only been two nuclear weapons ever used in a time of war. Both were dropped on Japan at the end of WWII by the United States military. Many other countries have developed and tested their own nuclear weapons, but none have been used to kill.
No, it was given that place right after WW2 before they had their own nuclear weapons.
No nuclear plant I know of uses weapons grade fissile material. This is strictly controlled for military use only.
No, but Japan banned them within their own territory themselves.
The U.S developed nuclear weapons to scare the Japanese and end world war 2 for the Americans ---------------------------------------------------------------------------------------------------------------------------------- Wrong! Actually the U.S. developed nuclear weapons in WW2 in an arms race with the supposed Nazi Germany project to do the same. Unknown to us, the German project soon stalled and concentrated on reactors not bombs. When Germany surrendered in spring 1945 the U.S. project continued as it was so close to finishing. In August the only 2 nuclear bombs used in war were dropped on Japan, prompting their surrender and ending the war. They were developed to defend against a possible German threat but got used against Japan to end the war. After the war, development slowed but was prompted by fears of the expansion of Soviet Communism. Development accelerated again after the USSR's 1949 test of their first nuclear bomb, causing an extended arms race.
North Korea has successfully tested a number of nuclear explosives. It is still unclear though if they have weaponized them. It is probable that they have succeeded in weaponization.