We've seen pictures of the melted core of Chernobyl too (the "Elephant's Foot") havent' we?
https://3.bp.blogspot.com/-KxRuWaD0sXg/U7MHoNyBuiI/AAAAAAAAJ...
http://rarehistoricalphotos.com/the-elephant-foot-of-the-che...
I couldn't find if robots were used here, but I'm sure more were later.
> From a safe distance, workers – or “liquidators” as they were called – rigged up a crude wheeled camera contraption and pushed it towards the Elephant’s Foot