My favorite kind of result. Much like how "tree huggers" celebrate blocking a nuclear reactor or bird-killing wind farm, and as a result the old sooty coal plant keeps running instead. Some victory. Some progress.
Sidenote, I'm sometimes a little befuddled that we would be afraid of putting radioactive material in the ground. The ground is already full of the stuff, and we don't spend much time worrying about an earthquake spitting up a boulder of yellow cake in our backyards. Ok, the concentration is different, but sometimes it seems like worrying about putting salt in the oceans.
Messing that up would be catastrophic. It is also the sort of dynamical system susceptible to bifurcation. The conveyor could potentially invert due to a threshold change in temperature or salinity. http://en.wikipedia.org/wiki/Bifurcation_theory
Not only is the concentration different, but also the composition. I haven't heard of plutonium occurring in nature.
Not entirely related, but an interesting read: http://en.wikipedia.org/wiki/Goi%C3%A2nia_accident
Not when you bring the timescales into account, recognize that you'd have to scale operations up massively from present levels (15,000 or so plants vs. the 436 presently operating in the world). This would mean commissioning and decommissioning about a plant per day.
Add to this questions over fuel availability (known reserves are good for about 80 years at present levels of use, 6 if used for all human energy needs), and the need to find some way for creating transport and storage fuels, and nuclear is at best a small part of a much larger energy solution.
An other direction would be to store it more safely but still accessible and work on techniques to reprocess the waste, especially that with long half-live. Of course that would mean we'd have to admit that nuclear energy is far more expensive than regenerative energy sources in the long run and nobody would want that...
[Edit: Please excuse the polemics. The topic is the source for a lot of heated debates in my social surroundings.]
A tl:dr; Earthquakes and rain.
A: If you bury drums of radioactive material you want to make sure that they stay sealed. However, on a 10,000 year time span, you cannot assume much. A very strong drum right now could be very weak in 5,000 years. Or, with one strong earthquake 2,000 years from now, it could crush the drums you've buried deep in the desert. As rainfall seems from the surface and into the water table, it will pull the radioactive material with it, then making the water supply unsafe.
Yucca Mountain was a popular site for a long time because it's a deep salt mine. Salt mines are interesting because it means that it's been impossible for water to flow thru them for millennia, which is the time scale you're concerned about here. From an engineering stand point, Yucca Mountain was just about the perfect solution, but it got killed politically because being 100 miles away from Las Vegas was "too close" for elected officials to stomach.
http://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_re...
Although the design questions are fascinating, the bigger issue that we need somewhere to store all of the nuclear waste. It's actually sitting in a variety of temporary facilities right now that aren't as safe as WIPP or Yucca mountain simply because it's very hard to get politicians to agree whose backyard gets to be the forever home for our spent fuel rods.
Source: My father has spent the last 20 years of his career with the Department of Transportation and Department of Energy working with transportation of hazardous and nuclear waste and took trips out to Yucca Mountain and WIPP.