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How to warn distant future generations about nuclear waste?

How do you leave a warning that lasts as long as nuclear waste? Phys Org, by Helen Gordon, 13 Sep 19  “……. First, it is difficult to predict how future generations will behave, what they will value and where they will want to go. Second, creating, maintaining and transmitting records of where waste is dumped will be essential in helping future generations protect themselves from the decisions we make today. Decisions that include how to dispose of some of today’s most hazardous material: high-level radioactive waste from nuclear power plants.

The red metal lift takes seven juddering minutes to travel nearly 500 metres down. Down, down through creamy limestone to reach a 160-million-year-old layer of clay. Here, deep beneath the sleepy fields and quiet woods along the border of the Meuse and Haute-Marne departments in north-east France, the French National Radioactive Waste Management Agency (Andra) has built its underground research laboratory.

The laboratory’s tunnels are brightly lit but mostly deserted, the air dry and dusty and filled with the hum of a ventilation unit. Blue and grey metal boxes house a series of ongoing experiments—measuring, for example, the corrosion rates of steel, the durability of concrete in contact with the clay. Using this information, Andra wants to build an immense network of tunnels here.

It plans to call this place Cigéo, and to fill it with dangerous radioactive waste. It is designed to be able to hold 80,000 cubic meters of waste……

High-level radioactive waste is primarily, spent fuel from nuclear reactors or the residues resulting from reprocessing that fuel. This waste is so potent that it must be isolated from humans until its levels of radiation, which decrease over time, are no longer hazardous. The timescale Andra is looking at is up to one million years……. Some scientists call this long-lived waste “the Achilles heel of nuclear power,” and it’s a problem for all of us—whatever our stance on nuclear. Even if all the world’s nuclear plants were to cease operating tomorrow, we would still have more than 240,000 tonnes of dangerously radioactive material to deal with.

Currently, nuclear waste is stored above ground or near the surface, but within the industry this is not considered an acceptable long-term solution. This kind of storage facility requires active monitoring. As well as regular refurbishment it must be protected from all kinds of hazards, including earthquakes, fires, floods and deliberate attacks by terrorists or enemy powers.

This not only places an unfair financial burden on our descendants, who may no longer even use nuclear power, but also assumes that in the future there will always be people with the knowledge and will to monitor the waste. On a million-year timescale this cannot be guaranteed.

So, after considering a range of options, governments and the nuclear industry have come to the view that deep, geological repositories are the best long-term approach. Building one of these is an enormous task that comes with host of complex safety concerns.

Finland has already begun construction of a geological repository (called Onkalo), and Sweden has begun the licensing process for its site. Andra expects to apply for its construction license within the next two years.

If Cigéo goes into operation it will house both the high-level waste and what is known as intermediate-level long-lived waste—such as reactor components. Once the repository has reached capacity, in perhaps 150 years’ time, the access tunnels will be backfilled and sealed up. If all goes according to plan, no one will ever enter the repository again……..

For waste buried deep underground, the major threat to public health comes from water contamination. If radioactive material from the waste were to mix with flowing water, it would be able to move relatively swiftly through the bedrock and into the soil and large bodies of water such as lakes and rivers, finally entering the food chain via plants, fish and other animals.

To prevent this, an underground repository such as Cigéo will take great care to shield the waste it stores. Within its walls there will be metal or concrete containers to block the radiation, and liquid waste can be mixed into a molten glass paste that will harden around it to stop leakage…….

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.

In 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, architects, archaeologists, philosophers and semioticians—social scientists who study signs, symbols and their use or interpretation………

In the very long term, though, 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, for example, 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……. https://phys.org/news/2019-09-nuclear.html?fbclid=IwAR2Kyunn90VCKgkNnwyGsMDYSYi3-UghDX7UNKcZNILzBuflZq2Gkq7daZE

September 14, 2019 - Posted by | 2 WORLD, wastes

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