They could do what the fossil fuel industry does and just disperse it into the atmosphere until it disappears behind background radiation.
Realistically deep geologic storage is absolutely fine, and even if it's not happening now, all of the waste can be safely stored above ground for hundreds of years.
After the Fukushima disaster, radioactivity was detected in the seawater off the west cost of America. This, of course, threw people into a panic, despite being detectable only with very sensitive equipment and was not a danger to anyone or anything.
To be more specific, you would not have been able to detect Fukushima waste based on radioactivity, as the radioactivity would not have been detectable above the normal background radiation.
They could only identify the waste by it's distinct radiological profile. Otherwise it was just another source amongst millions of ionizing radiation that bathes us every day.
Realistically deep geologic storage is absolutely fine, and even if it's not happening now, all of the waste can be safely stored above ground for hundreds of years.