Wait, for real? I have zero training in handling fissile material, but I didn't think any significant level of radiation could make it through that much shielding.
The radiation field of a freshly removed power reactor fuel element is so strong that you couldn’t run past it fast enough to survive the dose.
It looks like what I didn't understand is radiation-blocking of a material (lead, concrete, water) is actually a decay function (half of the radiation makes it through X feet) rather than an absolute function (no radiation makes it through X feet).
In other words, given an infinitely radioactive source, you would require an infinitely thick lead barrier to protect you.
Really, I should have guessed given everything else about radioactivity is the same way.
But many of the fission products in neutron-exposed uranium emit high-energy gammas. And even lead is somewhat transparent.
Also, from what Google tells me, those "infinity rooms" at Hanford are probably contaminated with plutonium-239. That's an alpha emitter, and alphas (helium-4 nuclei) are pretty easy to stop.
OK, consider a tall gantry crane on wheels.[0] Now imagine a plate, several feet thick, with layers of steel, lead and concrete, suspended below the rails. With a cab on the top, and no line of sight through the holes for the cables.
0) https://houstonforkliftsafety.com/wp-content/uploads/2016/07...