Chernobyl’s Hot Mess, “The Elephant’s Foot,” Is Still Lethal (2013)

This is 2013. Wiki says as of 2019, the mass has not moved significantly since its discovery and is estimated to be only slightly warmer than its environment due to heat from the ongoing nuclear decay

I believe I've also read there is a more significant risk from dry dust, than anything else, which the giant sarcophagus has mostly resolved: its a contained problem.