The waste situation with Thorium is different than with Uranium/Plutonium. It is definitely not benign (not that U/Pu is) but the byproducts from a Thorium reactor are significantly more radioactive than with U/Pu and they are much heavier in gamma radiation which is lots more hazardous and will eventually irradiate the building in which the reactor operates.
I am a fervent supporter of Thorium reactors in many, many aspects, but the waste issue with Th is potentially quite a bit more technically challenging than with U. At least, as far as I know from what I have read & researched. If I am wrong, that would be terrific news.
I think you meant to use the word "activate" rather than "irradiate".
I don’t claim to be an expert, but I’ve never heard about that.
The gamma radiation is what makes the waste useless for nuclear bomb fuel refinement, as it's results will apparently still be high enough in gamma to fry the electronics necessary to operate the device.