Chernobyl is back in the news due to an unexpected turn of events
www.earth.com
A study reveals that the cause of Chernobyl was not hidden fission, but changes in humidity inside the reactor, revealed by neutron spikes.

Neutron counts under the Chernobyl sarcophagus rose, but the best evidence says the spike came from shifting moisture inside the wrecked reactor, not an approaching chain reaction.