Nuclear waste and a communications conundrum

How to design a future-proof nuclear waste bunker

Every now and then, we find an item that intrigues and/or amuses us but does not fit easily into a category. The delightful and thought-provoking piece from The Economist is one such, reminding us of the opening of the  cult science fiction book of the late ’50s “A Canticle for Leibowitz” –  which recounts the discovery of a mystifying religious artifact – a handwritten note penned by the Blessed Leibowitz that reads “Pound pastrami, can kraut, six bagels–bring home for Emma.”

Oct 22nd 2007
The environmental lobby often laments mankind’s unfortunate obsession with the short term. People, by and large, don’t tend to think ahead (two-thirds of Britons lack wills, for example, leaving them unprepared for one of life’s few real certainties). Politicians, with one eye always fixed on surviving the next election, are particularly guilty of short-termism. That is a problem, since human time-scales don’t always match environmental ones. A razed rainforest may take decades to regrow. Climate change will remain a problem for centuries, even if carbon emissions were to cease tomorrow.
One of the thorniest long-term problems is what to do with nuclear waste. Many western countries may build new nuclear plants; they see the energy as clean and secure. But their publics remain dubious, and nuclear waste tops their list of worries. It is vicious stuff: high-level waste, made up of spent fuel, is lethally radioactive and remains that way for tens of thousands of years. Nevertheless, scientists believe they can dispose of it safely.
Every nation that has studied the problem has decided to bury the waste deep underground in geologically stable places unlikely to be disturbed by volcanoes or earthquakes. America and Finland have chosen their sites; other nations, including Britain, are still looking.
Still, while nature may not unearth the nuclear nasties that humanity has secreted away, people are much less predictable. At Yucca Mountain in the Nevada desert, the site of America’s first big nuclear waste dump, scientists are wrestling with the problem of how to remind future generations what is stored there. A similar study was carried out in the 1990s, when the Department of Energy assembled a team of linguists, archaeologists and materials scientists to study how to construct warning signs around a smaller waste dump in New Mexico that would last for 10,000 years.
Such a timescale presents a huge challenge. Ten thousand years is an immense, viscerally incomprehensible time, roughly equivalent to the entire history of human civilisation. Even such proverbially ancient things as Egypt’s 4,500-year old pyramids look young by comparison.
Speaking across such a cavernous gulf is difficult. Languages mutate rapidly: it is difficult for a modern English-speaker to understand the works of, say, Geoffrey Chaucer. In 1,000 years’ time–let alone ten thousand–a message written in any of today’s languages might be comprehensible only to professional linguists. On longer time-scales, future archaeologists may have to reconstruct today’s tongues from whatever fragments they can dig up, using the same combination of guesswork and inference they now use to decipher some ancient languages.
One method is to inscribe warnings on something large, erosion-resistant and eye-catching. Materials must be chosen carefully. Even messages inscribed on granite, one of the toughest rocks, would be unintelligible after thousands of years of erosion. And a monument with an unreadable message could be counterproductive, since future explorers may misinterpret it as marking something valuable or interesting.
Past erosion, there are deeper problems with using language to convey danger. There is no guarantee that a modern, technologically advanced civilisation will exist in 12,000 AD. Simple pictures, perhaps showing human skulls or screaming faces, may be a safer bet than warnings in a language that our descendants may be unable to decode.
On the other hand, attempts to scare intruders away could also do more harm than good. Future explorers will not necessarily meet a grisly death merely by wandering around on the surface. Unfulfilled promises of doom could convince people that the warnings are meaningless, encouraging them to start digging. After all, rumours of terrible curses failed to keep archaeologists and tomb-robbers from the graves of Egypt’s pharaohs.
The most radical argument of all holds that the best course of action is to seal the bunker off from the surface and leave no warnings at all. The hope is that any civilisation advanced enough to detect the bunker would also know enough to identify the materials inside, while a more primitive society would remain safely ignorant.
Current plans for Yucca Mountain call for a series of unnatural-looking 25-foot markers around the site entrance, designed to attract attention and to resist everything from floods to encroaching sand dunes. They would be inscribed with warnings in Arabic, Chinese, English, French, Russian and Spanish [note the use of the UN’s languages], with picture symbols as backup. Smaller, nine-inch markers would litter the site. A few larger monuments, built in the fan-shape of the international radiation symbol, would contain documents explaining what lies beneath.
Much thought has gone into the scheme, but no one really knows if it will work. Scientists plan to keep refining their ideas until the depository is finally sealed, which will not happen for many decades.
That, at least, is one advantage of dealing with long-term problems: there is no immediate deadline, and plenty of time to think things through.
Article with graphics and related items