What is 'subcritical nuclear test'?
米の「臨界前核実験」 被爆者から怒りの声上がる 長崎 | NHKニュース
臨界前核実験 - Wikipedia
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Do countries with nuclear weapons like the US have the right to stop other countries developing them?
Do you know how many countries have nuclear weapons?
Which country that has nuclear weapons is the most dangerous?
Are nuclear weapons really a big deterrent?