[prebrov]

Robots just kept dying in there all those years [1]. I reckon they are disposable, in effect.

[1]: http://mashable.com/2017/03/03/fukushima-robots-fail/

[vidarh]

That's the primary reason it's taken so long, as far as I understand. It's not that it was hard to find the location, per se, but that the robots didn't last long enough.