How do we keep nuclear waste secure forever?

If civilization were to collapse tomorrow, mankind would be survived by no artifact as long-lived as our nuclear waste. And that presents an interesting problem — namely, how do we keep our progeny away from the stuff?

The tomb of the ancient Egyptian vizier Khentika (also known as Ikhekhi), for example, contains the inscription: “As for all men who shall enter this my tomb … impure … there will be judgment … an end shall be made for him. … I shall seize his neck like a bird. … I shall cast the fear of myself into him.” It’s possible that the vizier’s contemporaries took Khentika at his word. But 20th-century archaeologists with wildly different religious beliefs had no reason to take the neck-cracking threat seriously. Likewise, a scavenger on the Carlsbad site in the year 12,000 C.E. may dismiss the menace of radiation poisoning as mere superstition. (”So I’m supposed to think that if I dig here, invisible energy beams will kill me?”) Hence the crux of the problem: Not only must intruders understand the message that nuclear waste is near and dangerous; they must also believe it.

Of course, the simplest solution is simply to maintain a semblance of civilization in perpetuity. And, as Matt Yglesias points out, if civilization does collapse, nuclear waste probably ain’t the biggest thing our descendants wind up facing.