Most people are killed by the blast and heat as in conventional explosions.
However the radioactivity adds both immediate and long term deaths (e.g. radiation poisoning, cancers). Radioactive fallout can produce deaths many hundreds of miles away from the explosion itself.
nuclear explosion?
Most illnesses were cancer related because of the ionising radiation in the nuclear fall-out after the explosion.
it kills people
new clear weapons
If you are sufficiently close to the explosions center it is possible.Temperture of explosion center is 300,000,000°C.
When and what explosion? One of the nuclear test shots. If so which?Remember Chernobyl was not a nuclear explosion, it was a steam explosion and graphite fire.
The only nuclear explosions in Japan were the two in WW2, on Hiroshima and Nagasaki.However I believe you meant the Japanese nuclear reactorexplosion, which was not a nuclear explosion it was either a steam explosion and/or a hydrogen/oxygen chemical explosion. That occurred at Fukushima.
lots
Chernobyl
You don't, they are dead or will be dead in a few weeks.
no
Nuclear Power is NOT NECESSARY. So many people die when there's a nuclear explosion. It is also really bad for the environment.