En enero de 1997, La tripulación de un barco pesquero en el Mar Báltico encontró algo inusual en sus redes:un bulto grasiento de color marrón amarillento de material arcilloso. Lo sacaron lo colocó en cubierta y volvió a procesar su captura. El día siguiente, la tripulación enfermó con graves quemaduras en la piel. Cuatro fueron hospitalizados. El bulto graso era una sustancia llamada yperita, más conocido como mostaza azufrada o gas mostaza, solidificado por la temperatura en el fondo del mar.

Al final de la Segunda Guerra Mundial, los Estados Unidos, Británico, Las autoridades francesas y soviéticas se enfrentaron a un gran problema:cómo deshacerse de unos 300, 000 toneladas de municiones químicas recuperadas de la Alemania ocupada. A menudo, optaron por lo que parecía lo más seguro, El método más barato y sencillo:tirar las cosas al mar.

Las estimaciones son que al menos 40, 000 toneladas de municiones químicas se eliminaron en el Mar Báltico, no todo en las zonas de vertido designadas. Algunas de estas ubicaciones están marcadas en gráficos de envío, pero registros completos de exactamente lo que se arrojó y dónde no existen. Esto aumenta la probabilidad de que las tripulaciones de los arrastreros, y otros, entrar en contacto con este peligroso residuo.

El problema no va a desaparecer especialmente con un mayor uso del fondo marino con fines económicos, incluyendo oleoductos, cables marítimos y parques eólicos marinos.

La historia de esos desafortunados pescadores ilustra dos puntos. Primero, es difícil predecir cómo se comportarán las generaciones futuras, qué valorarán y adónde querrán ir. Segundo, creando Mantener y transmitir registros de dónde se vierten los desechos será esencial para ayudar a las generaciones futuras a protegerse de las decisiones que tomamos hoy. Decisiones que incluyen cómo deshacerse de algunos de los materiales más peligrosos de la actualidad:desechos radiactivos de alto nivel de las plantas de energía nuclear.

El elevador de metal rojo tarda siete temblorosos minutos en recorrer casi 500 metros hacia abajo. Abajo, a través de piedra caliza cremosa para llegar a una capa de arcilla de 160 millones de años. Aquí, en lo profundo de los campos somnolientos y los bosques tranquilos a lo largo de la frontera de los departamentos de Mosa y Haute-Marne en el noreste de Francia, la Agencia Nacional Francesa de Gestión de Residuos Radiactivos (Andra) ha construido su laboratorio de investigación subterráneo.

Los túneles del laboratorio están muy iluminados, pero en su mayoría están desiertos. el aire seco y polvoriento y lleno con el zumbido de una unidad de ventilación. Las cajas de metal azul y gris albergan una serie de experimentos en curso:medir, por ejemplo, las tasas de corrosión del acero, la durabilidad del hormigón en contacto con la arcilla. Usando esta información, Andra quiere construir aquí una inmensa red de túneles.

Planea llamar a este lugar Cigéo, y llenarlo con desechos radiactivos peligrosos. Está diseñado para contener 80, 000 metros cúbicos de residuos.

Estamos expuestos a la radiación todos los días. Public Health England estima que en un año típico, alguien en el Reino Unido podría recibir una dosis promedio de 2,7 milisieverts (mSv) de fuentes de radiación naturales y artificiales. Un vuelo transatlántico por ejemplo, lo expone a 0.08 mSv; una radiografía dental a 0,005 mSv; 100 gramos de nueces de Brasil a 0.01 mSv.

Los desechos radiactivos de alto nivel son diferentes. Está, ante todo, combustible gastado de reactores nucleares o los residuos resultantes del reprocesamiento de ese combustible. Este desperdicio es tan potente que debe aislarse de los humanos hasta sus niveles de radiación, que disminuyen con el tiempo, ya no son peligrosos. La escala de tiempo que Andra está mirando es de hasta un millón de años. (Para poner esto en algún tipo de contexto, son solo 4, Hace 500 años que se construyó Stonehenge. Alrededor de los 40, 000 años atrás, los humanos modernos llegaron al norte de Europa. Hace un millón de años el continente estaba en medio de una Edad de Hielo. Los mamuts vagaban por el paisaje helado.)

Algunos científicos llaman a este desperdicio de larga duración "el talón de Aquiles de la energía nuclear, "y es un problema para todos nosotros, cualquiera que sea nuestra postura sobre la energía nuclear. Incluso si todas las plantas nucleares del mundo dejaran de funcionar mañana, todavía tendríamos más de 240, 000 toneladas de material peligrosamente radiactivo para tratar.

En la actualidad, los desechos nucleares se almacenan sobre el suelo o cerca de la superficie, pero dentro de la industria esto no se considera una solución aceptable a largo plazo. Este tipo de instalación de almacenamiento requiere un seguimiento activo. Además de las renovaciones periódicas, debe protegerse de todo tipo de peligros, incluyendo terremotos, incendios inundaciones y ataques deliberados de terroristas o potencias enemigas.

Esto no solo impone una carga financiera injusta a nuestros descendientes, que puede que ya ni siquiera utilice la energía nuclear, pero también asume que en el futuro siempre habrá personas con el conocimiento y la voluntad de monitorear el desperdicio. En una escala de tiempo de un millón de años, esto no se puede garantizar.

Entonces, después de considerar una variedad de opciones, Los gobiernos y la industria nuclear han llegado a la opinión de que, en Los repositorios geológicos son el mejor enfoque a largo plazo. Construir uno de estos es una tarea enorme que conlleva una serie de problemas de seguridad complejos.

Finlandia ya ha comenzado la construcción de un depósito geológico (llamado Onkalo), y Suecia ha comenzado el proceso de concesión de licencias para su sitio. Andra espera solicitar su licencia de construcción dentro de los próximos dos años.

Si Cigéo entra en funcionamiento, albergará tanto los residuos de alta actividad como los que se conocen como residuos de larga duración de nivel intermedio, como los componentes del reactor. Una vez que el repositorio haya alcanzado su capacidad, en quizás 150 años, los túneles de acceso se rellenarán y sellarán. Si todo va de acuerdo al plan, nadie volverá a entrar en el repositorio.

Párese frente a una fuente de radiación sin protección y no verá ni sentirá nada. Sin embargo, parte de esa radiación pasará a su cuerpo. Los desechos nucleares son peligrosos porque emiten radiación ionizante en forma de partículas alfa y beta y rayos gamma. Mientras que las partículas alfa son demasiado débiles para penetrar la piel, las partículas beta pueden provocar quemaduras. Si se ingiere, ambos pueden dañar los tejidos y órganos internos.

Son rayos gamma sin embargo, que tienen el mayor rango de penetración, y por lo tanto, el potencial de causar el daño más generalizado al ADN de sus células. Este daño puede conducir a un mayor riesgo de cáncer en el futuro. y es en gran parte responsable del conjunto de síntomas conocidos como enfermedad por radiación.

Algunos expertos estiman que una dosis de más de 1 sievert es suficiente para causar enfermedad por radiación. Los síntomas incluyen náuseas, vómitos ampollas y úlceras; estos pueden comenzar a los pocos minutos de la exposición o demorarse varios días. La recuperación es posible, pero cuanto mayor es la dosis de radiación, menos probable es. Típicamente, la muerte proviene de infecciones y hemorragias internas provocadas por la destrucción de la médula ósea.

Para los desechos enterrados profundamente bajo tierra, la principal amenaza para la salud pública proviene de la contaminación del agua. Si el material radiactivo de los desechos se mezclara con agua corriente, podría moverse con relativa rapidez a través del lecho rocoso y hacia el suelo y grandes masas de agua como lagos y ríos, finalmente ingresando a la cadena alimentaria a través de las plantas, peces y otros animales.

Para prevenir esto, un depósito subterráneo como Cigéo cuidará mucho de proteger los residuos que almacena. Dentro de sus paredes habrá contenedores de metal u hormigón para bloquear la radiación, y los desechos líquidos se pueden mezclar en una pasta de vidrio fundido que se endurecerá a su alrededor para detener las fugas.

Más allá de esas barreras los planificadores eligen sus sitios con cuidado, para que puedan explotar las propiedades de la roca circundante. En Cigéo, el jefe de prensa Mathieu Saint-Louis me dice:la arcilla es estable y tiene una permeabilidad muy baja, dificultando que cualquier material radiactivo llegue a la superficie. Después de alrededor de 100, 000 años unas pocas sustancias muy móviles con una vida media larga, como el yodo-129, podría lograr migrar hacia arriba en cantidades extremadamente pequeñas, pero en ese punto, Saint-Louis dice:el "impacto potencial sobre los seres humanos y el medio ambiente es mucho menor que el de la radiactividad que está presente de forma natural en el medio ambiente".

Deep geological repositories are designed as passive systems, meaning that once Cigéo is closed, no further maintenance or monitoring is required. Much more difficult to plan for is the risk of human intrusion, whether inadvertent or deliberate.

En 1980, the US Department of Energy created the Human Interference Task Force to investigate the problem of human intrusion into waste repositories. What was the best way to prevent people many thousands of years in the future from entering a repository and either coming into direct contact with the waste or damaging the repository, leading to environmental contamination?

Over the next 15 years a wide variety of experts were involved in this and subsequent projects, including materials scientists, anthropologists, arquitectos, arqueólogos, philosophers and semioticians—social scientists who study signs, symbols and their use or interpretation.

Science fiction author Stanislaw Lem suggested growing plants with warning messages about the repository encoded in their DNA. Biologist Françoise Bastide and semiotician Paolo Fabbri developed what they called the "ray cat solution"—cats genetically altered to glow when in the presence of radiation.

Quite apart from the technological challenges and ethical issues these solutions present, both have one major drawback:to be successful they rely on external, uncontrollable factors. How could the knowledge required to interpret these things be guaranteed to last?

Semiotician Thomas Sebeok recommended the creation of a so-called Atomic Priesthood. Members of the priesthood would preserve information about the waste repositories and hand it on to newly initiated members, ensuring a transfer of knowledge through the generations.

Considered one way, this is not too different from our current system of atomic science, where a senior scientist passes on their knowledge to a Ph.D. candidato. Pero aún, putting such knowledge, and therefore power, into the hands of one small, elite group of people is a high-risk strategy easily open to abuse.

Perhaps a better way to warn our descendants about the waste is to talk to them directly, in the form of a message.

At Andra's headquarters outside of Paris, Jean-Noël Dumont, head of Andra's memory program, shows me a box. Dentro, fixed in plastic cases, are two transparent discs, each around 20 centimeters in diameter. "These are the sapphire discs, " he says. The brainchild of Dumont's predecessor, Patrick Charton, each disc is made of transparent industrial sapphire, inside which information is engraved using platinum.

Costing around 25, 000 euros per disc, the sapphire (chosen for its durability and resistance to weathering and scratching) could last for nearly 2 million years—though one disc already has a crack in it, the result of a clumsy visitor on one of Andra's open days.

In the very long term, aunque, these plans also have a major drawback:how can we know that anyone living one million years in the future will understand any of the languages spoken today?

Think of the differences between modern and Old English. Who of us can understand "Ðunor cymð of hætan &of wætan"? That—meaning "Thunder comes from heat and from moisture"—is a mere thousand years old.

Languages also have a habit of disappearing. Around 4, 000 years ago in the Indus Valley in what is now Pakistan and north-west India, por ejemplo, people were writing in a script that remains completely indecipherable to modern researchers. In one million years it is unlikely that any language spoken today will still exist.

A principios de la década de 1990, architectural theorist Michael Brill sought a way to side-step the issue of language. He imagined deterrent landscapes, "non-natural, ominous, and repulsive, " constructed of giant, menacing earthworks in the shape of jagged lightning bolts or other shapes that "suggest danger to the body... wounding forms, like thorns and spikes."

Anyone venturing further into the complex would then discover a series of standing stones with warning information about the radioactive waste written in seven different languages—but even if these proved unreadable, the landscape itself should act as a warning. To help convey a sense of danger there would be carvings of human faces expressing horror and terror. One idea was to base them on Edvard Munch's The Scream.

The drawback is that such a landscape—a strange, disturbing wonder—would probably attract rather than repel visitors. "We are adventurers. We are drawn to conquer forbidding environments, " says Florian Blanquer, a semiotician hired by Andra. "Think about Antarctica, Mount Everest."

Or think about the 20th-century European archaeologists, people not noticeably hesitant when it came to opening up the tombs of Egyptian kings, despite the warnings and curses inscribed on their walls.

As Dumont sees it, a memory program is necessary for three main reasons. Primero, to avoid the risk of human intrusion by informing future generations about the existence and contents of Cigéo.

Segundo, to give future generations as much information as possible to allow them to make their own decisions about the waste. They might, por ejemplo, want to retrieve the waste because new uses or solutions have arisen. Gerry Thomas, chair in molecular pathology at Imperial College London, believes that much of the waste destined for repositories may one day provide an important new non-carbon fuel source.

Tercera, cultural heritage:a properly documented geological repository would provide a wealth of information for a future archaeologist. "I have no knowledge of other places or systems where you have at the same time objects from the past and very large, concrete descriptions of how these products were manufactured, where they come from, how we considered them and so on, " says Dumont.

One way that memory is transmitted is orally, de generacion a generacion. To study this, Dumont asked researchers to consider historical examples of oral transmission, using as a case study the 17th-century Canal du Midi between the Mediterranean and Atlantic Ocean. Aquí, for 300 years, the same families have worked on maintaining the canal, passing down know-how from father to son.

Dumont also talks about the need to ensure that as many people as possible hear about Cigéo. As part of this strategy, Andra has held a series of annual competitions asking artists to suggest ways to mark the site. Por ejemplo, Les Nouveaux Voisins, winners of the 2016 prize, imagined constructing 80 concrete pillars, 30 metres high, each with an oak tree planted at the top. As the years passed, the pillars would slowly sink and the oak trees replace them, leaving tangible traces both above and below the repository.

Leaving Andra's visitors' center, I drive through a landscape patchworked with colors, from the russet of the woods to the bright limey green of a wheat field, towards Bure, a tiny village of around 90 inhabitants. The population is aging.

"Young people can't stay here if they want to study and find jobs, " Benoît Jaquet tells me. A village that once supported around ten farmers is now home to only two or three. Although not a resident of Bure, Jaquet is the general secretary of CLIS, an organization of local elected officials, representatives from trade unions and professional bodies, and environmental associations. Its purpose is to provide the local community with information about Cigéo, host public meetings, and monitor the work of Andra by, por ejemplo, commissioning independent experts to review the agency's work.

If the repository is built, Jaquet says, French law requires that CLIS be transformed into a local commission that will last as long as the repository. "So it's also a way to pass the baton, " he says. "If there is a local commission there is a memory—not Andra's memory but an external memory."

Al mismo tiempo, Andra has set up three regional memory groups, each composed of around 20 interested locals. They meet every six months and make their own suggestions for passing on the memory of the repository. Ideas so far include collecting and preserving oral witness accounts and developing an annual remembrance ceremony to take place on the site, organized by and for the local people. A nuclear beating the bounds, a radioactive summer solstice, an atomic maypole.

This last idea resonates with the work of Claudio Pescatore and Claire Mays, former employees of the Nuclear Energy Agency, a Paris-based body that supports intergovernmental cooperation on nuclear issues. They wrote in a research paper:"Do not hide these facilities; do not keep them apart, but make them A PART of the community… something that belongs to the local, social fabric." They went on to suggest that a monument celebrating the repository could be created, and argued that if it had "a distinctiveness and aesthetic quality, would this not be one reason for communities to proudly own the site and maintain it?"

Could the repository, I ask Jaquet, one day become a tourist destination? De lo contrario, él dice, some members of the CLIS say that "every person living here will quit the district because of the risk, because of the image of the repository as a rubbish bin. Of course some also think the repository will create employment and that this will become a new Silicon Valley. Maybe the reality will be somewhere between the two—but a tourist attraction? I'm not sure about that."

Across the road from CLIS and the town hall is a large, ramshackle stone house decorated with a banner. It translates:"Free zone of Bure:house of resistance against nuclear waste." Since 2004, this has been home to a rotating group of international anti-nuclear, anti-repository protesters. By continually campaigning against Cigéo—and, presumiblemente, by passing their beliefs on to future generations—the protesters would necessarily keep the memory of the repository alive and in the public eye, the ramshackle stone house becoming its own sort of monument for Cigéo.

"So in fact the pro-repository groups need the anti-repository groups to stay alive in order to provide a good memory, " says Florian Blanquer. "Fortunately, we are in France—in France there are always opponents to something!"

Rely only on the transmission of knowledge between generations and you can never guarantee an unbroken line of succession. Rely only on direct communication and you risk leaving behind a message that, even if it survives physically, eventually no one will be able to understand. So Andra asked Blanquer to research how to convey a message without written language.

Many visual signs are, like languages, culturally specific. Es más, we know that the meanings of signs are not always stable over time.

Todavía, Blanquer thought that there was one universal sign:an image of a human figure. "And every human being… apprehends its body through space the same way as well. There is an up and down, a left and right, a front and back, " he wrote in a conference paper. Pictographs (pictorial symbols for a word or phrase) based on an anthropomorphic figure in movement are likely to be recognized universally, he decided.

Now he had the beginnings of an idea, but it wasn't enough. You might draw a cartoon strip showing a person approaching a piece of radioactive waste, touching it and falling down. But how can you guarantee that the panels will be read in the correct order? Or that touching the waste will be interpreted as a negative action? And how can a pictograph relying on the visual representation of tangible objects convey a message about radioactivity—something that can be neither seen nor touched?

In response to these problems, Blanquer has designed what he calls a "praxeological device." Independent of any verbal language, it works by teaching the person encountering it a brand-new communication system created specially for this purpose.

Blanquer envisages a series of passages built underground, perhaps in the access tunnels of the repository. On the wall of the first passage is a rectangular pictograph showing a person walking along the passage and a line of footprints indicating the direction of movement.

At the end of the corridor is a hole and a ladder and three more pictographs. A circular pictograph shows a person holding on to the ladder; a triangular pictograph shows a person not holding on and consequently falling off. And so it continues.

In this way you begin to establish patterns:you learn first that the figure drawn on the walls relates to a person's actions here, and second that you should copy the actions in the circles and avoid the actions in the triangles. "What is really interesting is the idea of people learning by themselves, " Dumont says. "Learning is important in the long term when you cannot just rely on transmission from generation to generation."

There has been one more radical proposal about how to deal with the threat of human intrusion—hide the repository completely from future generations.

Some argue that because the repositories are passive systems, most likely buried far underground in areas with no deep natural resources, the question of memory preservation is moot.

En la actualidad, no one can conceive of a reason why anyone in the future might want to dig down 490 meters to reach the clay formation that Cigéo is planned for. This reduces the chances of inadvertent intrusion. And after around, decir, 100, 000 años, almost all surface traces and any complex above-ground markers will have vanished. The only things left behind will be some slight indentations, perhaps a gentle protuberance or two. Things that to the untrained eye may appear to be only the natural shape of the land. Eventually it will be as though no one was ever there, as though there is nothing for anyone to remember.

But Blanquer warns that forgetting is not so easy:"You cannot say to yourself, "I will forget about that." It's like trying not to think about pink elephants. If you want to forget about it then first you have to get rid of any information about it. That would mean shutting down the web and destroying a lot of computers, a lot of newspapers, a lot of books."

In his opinion it is no longer possible that Cigéo could become, as Danish film maker Michael Madsen has said about the Finnish repository, "the place you must always remember to forget."

Last summer I set out with some friends to walk part of the Ridgeway, an ancient long-distance route through the Chiltern Hills and North Wessex Downs in the south of England. On Whiteleaf Hill, the chalky white path passes near the remains of a Neolithic barrow, around 5, 000 años. You can tell immediately that it's not natural, the way the earth has been lumped up on the hillside, but today there is little to see except a low grassy mound with a view over the fields and woods of Buckinghamshire and the small town of Princes Risborough.

We don't know who built the burial chamber or the name of the person interred there, what language they spoke and what they believed the world would be like in 5, 000 años. Staring at the barrow, it was not continuity with the past I felt, but distance.

In the 1930s an archaeologist called Lindsay Scott broke open the Whiteleaf Hill barrow and discovered the remains of a human skeleton, around 60 pieces of pottery, flint shards and animal bones. And just as we enter burial chambers in search of answers, so archaeologists of the future may one day find themselves penetrating the concrete passageways and tunnels of the place we call Cigéo.

Peering into the darkness they will ask themselves, who built this place and why? Why did they come here, digging down so far below the surface of the land? What were they running from, or trying to hide?

In the light they carry, the archaeologists will see markings on the passage walls. Moving closer, they make out a series of footprints stretching away in front of them, down the passageway. In the looming darkness, it becomes clear—someone has left them a message.

This article first appeared on Mosaic and is republished here under a Creative Commons licence.