A serious incident is created when nuclear material is released by accident and humans are exposed to dangerous radiation levels, which can/will either cause death and/or injury. The earliest known event was in 1942 in Nazi Germany when an experimental reactor exploded and probably injured or killed several people. The first such incident in the US was at Los Alamos National Laboratory in 1945, when a scientist accidentally dropped tungsten brick into a plutonium core, causing critical mass and the scientist was fatally irradiated.
There have been over 60 such incidents since the first two and experts believe there were probably many more unreported. Of course there were the widely publicized incidents at Three Mile Island, Chernobyl, and the most recent, Fukushima. Reactors can be dangerous, when releases are massive like Fukushima, thousands have and will die within 5 years and maybe a million will die worldwide from cancer deaths over the next several decades. So it is not an understatement to say that nuclear materials are super dangerous to living things.
An event called “broken arrow” is the military code name for aircraft with nuclear weapons on board or nuclear submarine that is in trouble. Amazingly no major disaster have occurred, even though with that many Broken Arrow incidents chances were high that a detonation should have or could have occurred. These incidents have occurred all over the country from Albuquerque, New Mexico (2); Lebanon, Ohio; Golden, Colorado; Savannah, Georgia; and several other locations around the US and Canada.
And of course there is the not so accidental nuclear war, which has not yet happened since we (the US) killed thousands, many innocent civilians, in Japan. There are eight known countries with nuclear warheads – totaling about 10,000 warheads – enough death and destruction to destroy the entire world one hundred times over. So will it happen? I say absolutely never. And the answer is simple they will not let us destroy our world. They being several alien groups (non-human) that share this planet with us. The Japan nuclear bombing was the first and the last in the modern times. There always has been rumored in ancient times there was a nuclear war in the Middle East and/or the Indian sub-continent; however, the bottom line here is that they will stop it. They have stopped it in the past. One example was in the 60’s several well-documented incidents where firing codes at the SAC nuclear missile locations were mysteriously changed. To keep missiles from firing and signaling to the US that they were in charge. It has also been said that the Russians have experienced similar intrusions in their nuclear missile bunkers system codes. Good for the world – finally someone with more sense than us.
Sleep-tight – there is someone (non-human) looking over us