One of the ways of dealing with nuclear waste at the moment is to bury it deep underground. We can hope that this is just a temporary solution, and that we eventually find some way of processing or disposing of it in the future. However, since we don't have any of those kinds of solutions yet, exactly how do you go about designing warning signs that will last as long as the dangers they are warning about?
Metal signs can rust away. Plastics last a long time, but can they last long enough to still be around for the millions of years that some of these radioactive substances remain dangerous? Stone may work, but stone can crumble.
Even if we come up with a good medium, what will the message be? We can't completely rely on written warnings, because it's doubtful that our current languages will exist for the millions of years some of radioactive elements take to finally decay away. We also can't rely on civilization to continue to update the warnings, because we have to consider the possibility of civilization collapsing due to disaster or war, and these things could end up forgotten as new civilizations build up in the aftermath.
When the U.S. Department of Energy proposed its Waste Isolation Pilot Plant (WIPP), located in the Delaware Basin, in New Mexico, it hired a team of anthropologists, scientists, linguists, futurists and science fiction writers to figure these things out.
A report with the cumbersome title 'Expert Judgement on Markers to Deter Inadvertent Human Intrusion into the Waste Isolation Pilot Plant' goes through some of the ideas, with the overarching theme of the plan being to make the purpose of the site entirely unmistakable, even on a non-verbal level. The team agreed on the following:
The marking of the site must be a system, where each individual marker relates to all the other markers in a way that contributes to the overall message. No individual component can stand apart from this, because that component may be damaged or destroyed and that part of the message would be lost.
Every aspect of the system must have redundancy, so that any part of the whole that is still left behind in the far future will still convey the intended message.
Nothing used on site should be intrinsically valuable, so that people will not be tempted to dismantle the warnings.
Every aspect of the look of the site has to leave the impression that it is a dangerous place, better left alone.
The site should not provide any form of shelter from the elements, to deter people from possibly settling there, completely unaware of the danger under their feet.
David Givens, the director of the Center for Non-verbal Studies, who was part of the team that put together these ideas, identified four levels of communication the site must use:
Level I: Rudimentary Information — "Something man-made is here"
Level II: Cautionary Information — "Something man-made is here and it is dangerous"
Level III: Basic Information — Tells what, why, when, where, who, and how (in terms of information relay, not how the site was constructed)
Level IV: Complex Information — Highly detailed written records, tables, figures, graphs, maps and diagrams
The team decided the basic design of the site could be used to convey Level I and Level II messages to visitors, 'non-linguistically', to say:
This place is a message... and part of a system of messages... pay attention to it!
Sending this message was important to us. We considered ourselves to be a powerful culture.
This place is not a place of honor...no highly esteemed deed is commemorated here... nothing valued is here.
What is here is dangerous and repulsive to us. This message is a warning about danger.
The danger is in a particular location... it increases toward a center... the center of danger is here... of a particular size and shape, and below us.
The danger is still present, in your time, as it was in ours.
The danger is to the body, and it can kill.
The form of the danger is an emanation of energy.
The danger is unleashed only if you substantially disturb this place physically. This place is best shunned and left uninhabited.
More complex levels of communication would be conveyed by pictographs showing images of people ill or in pain (possibly even an image of Edvard Munch's The Scream), as well as inscriptions carved into rock in many of the major languages of the world.
The team is not due to submit their final recommendations until 2028 (since the WIPP site will be accepting waste materials for around 30 years or so), but they have come up with some specific design ideas, including making massive stone spikes protruding from the ground, or a variation on that idea they called "a landscape of thorns", which made the massive spikes look more like thorny brambles. Another idea was to build up earthenberms around the site which together would form a pictograph of radiating energy. Yet another plan would build up massive 'forbidding blocks' over the site, each roughly 7.6 m square, and set only about 1.5 m apart, but deliberately made irregular, jagged and foreboding.
The current design idea for WIPP is for a system of 'passive institutional controls.' Thirty-two granite pillars, each 7.6 m tall, will form a 6 km square around the site and will have the first warnings, engraved on their above-ground and below-ground surfaces, to ensure that some part of the message survives. Further in, just outside of a 10 m tall, 30 m wide earthen wall — called a berm — will be a 'hot cell,' of the same type used to store hazardous materials under the site, to show the dangers present. Storage rooms buried inside the berm, only accessible through a massive 725 kg stone plug in the side of the room, will contain large engraved granite slabs with further warning messages. Inside the perimeter of the berm there will be 16 more granite pillars, with more warnings, and at the middle of the site, directly over the entrance to the waste dump, will be a roofless granite room. This 'information room' will contain more engraved granite slabs with information on the site carved in various languages, as well as a world map showing the location of other disposal sites and a pictograph showing the structure and purpose of the entire site.
You can view an interactive pdf document of the site at here. The image just to the left of the centre of the page is particularly interesting, as you can click on various parts to bring up more information about the design.
The proposal for the site is expected to remain effective — legible and understandable — for 12,000 years. This falls far short of the millions of years the dangers will persist, however they still have another 14 years to refine the idea, so we may have some technological advances between now and then that substantially increase the durability of the site.