No warning needed - it won't be there long (Score 1)

A warning to work for 10,000 won't be needed because the material won't be there. Within a few hundred years, that radioactive "waste" will be dug up and reused. Like the air you exhale still contains most of the oxygen, the fuel we discard still contains a large fraction of the enriched material. Since Jimmy Carter banned reprocessing in the 1970's, we have no choice but to dispose of fuel that still contains large amounts of usable material in the form of (principly) U-235 and P-238. In a typical power reactor today, by the end of the fuel cycle 30%-40% of the energy is coming from fissioning plutonium. The fuel is discharged because there is too high a build-up of fission products that absorb neutrons. Just like suffocating in a closed room. It's not the lack of oxygen that gets you, it's the buildup of carbon dioxide. Back to my point, before too long people will figure out that throwing away fuel that took large amounts of electricty to enrich is a bad idea. Within 300 years all the short lived, high energy fission products will have decayed leaving only the long lived, low energy materials like Uranium and Plutonium. You can handle those with your hands with no shielding. (Little known fact: Plutonium is an alpha emitter. A sheet of paper will stop all radiation from plutionium. As long as you don't eat it or breath it in, it won't hurt you.) So our decendents will say "thank you," dig up the material, reprocess it, and keep their "X-box 36 Million" consoles and electric flying cars running. If there are signs, they should say "Dig here! Free energy!" (Know your sources - I've been a Nuclear Engineer for 25 years)