christ for the misinformed madcow, a nuclear powerplant does not explode in a 'nuclear explosion' like someome dropped an h-bomb in the middle of Prypiat, what happened was a fubarred test caused all the control rods (what regulate the reactors, er, reaction) to become stuck and inoperable, so the reaction increased exponentially till the reactor blew its top off in a steam explosion, this released the radioactive contaminents into the air as a massive jet of steam and the wind carried them over most of europe. Pryapit was not evacuated before it happened as the events leading to the explosion were within a few minutes iirc, the men were taken out the town and used to cleanup the mess, leading to horrendous radiation injuries/fatalities. Everyone else was evacuated by the KGB and the town was left desolate.
Nuclear plants are considerably safer than they were back then and I see them as the only real way of providing energy for future generations, you couldn't cover the UK in enough wind farms to compete with the kind of energy nuclear plants can provide. France gets most of its energy from nuclear fission and it hasnt blown up in a while. The main drawback is, as mentioned, nuclear waste, its nasty stuff and the only real way to deal with it is to bury it underground and forget about it, designing the grave they are put in to last for some 100,000 years.