ELI5 Nuclear Disasters - why is Hiroshima alive but Chernobyl dead?

Why is Hiroshima a vibrant city today, vs a dead city like Chernobyl which still has sa 30km exclusion zone? How do countries get rid of nuclear warheads when they no longer need them? How are nuclear weapons tests conducted underground without destroying everything around them? ELI5 what happened at Chernobyl? ... we explain like I'm five Thank you to the r/explainlikeimfive community and in particular the following users whose questions and comments formed the basis of this discussion: iisystematic, brainwired1, gfrisse1, temioo, the_other_goat, kent1146, clovis69, doctor_zonk, rilkespawn, clotzyninja and je_kay24. To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]