Landon, there is no fungal solution. In fact there is no biological solution, the radioactivity at Hanford needs to be removed from the biosphere completely.
Unfortunately, being the first plutonium production reactor that was built, they really had no idea what they were in for as far as how to dispose of the nuclear waste. Now that waste sits in tanks, and they try to think of how to get it pumped from leaking single wall tanks into double walled tanks, and then if they fail, where can they put triple wall tanks, and.......oh, it's a mess.
The best way I can think of is for them to set off a nuclear device 2000' down (or more if the geology is right), make a huge cavern with the explosion (like was done in Operation Plowshare), and then
pump all the high level waste into the hole. Hope that the geology is right and that it will stay there for a few million more years.
The problem of nuclear waste is one of being painted into a corner. There is just no way to get out of that corner without making more of a mess, somehow, somewhere. Chernobyl is one corner, Fukushima is another, Hanford is a third. At least the radioactive material is mostly contained at Hanford unlike it is at the other two. For those, there is only the Sneferu solution -- put one of these on top of the mess: