How long will the Chernobyl exclusion zone stay unfit for human habitation?

Answer 1

Probably about 50 years, before the worst of the actinides begin to decay extensively, The problem with Chernobyl was that the reactor was a PILE of graphite blocks - i.e., COAL, and when the reactor overheated it started a fire - burning up the coal that was supposed to calm down the radiation! VERY bad JuJu to start a coal fire INSIDE a melting nuclear reactor.

In Japan, several reactors were shut down immediately after the Earthquake, and the reactors were "scrammed" with the moderating rods fully inserted to stop the reaction. But the reactors still needed to be cooled, and so several diesel generators were started (all part of the master plan!) to pump water around to keep the reactor cool. That worked fine for about an hour, until the tsunami drowned the diesel generators that powered the pumps. Some, but not enough, of the diesel generators were brought back on line and other generators are being flown in.

Answer 2

Ukrainian officials say the area will be uninhabitable for around 20,000 years due to the long half life of the radioactive isotopes