From Salt Mines to Floating Stars as Nuclear Waste Disposals

In 1964 the salt mining operations become economically unviable and suspended at the Lower Saxony area, in Germany. A year later, in 1965 was the moment when the Asse II Salt Mine started being used as a research mine and storage site for more than a hundred thousand barrels of low- to medium-level nuclear waste. According to A brief history of the nuclear waste repository Asse II by Hubert Mania, about 125,000 barrels of weak radioactive waste is stored in the Asse mine, under the banner of research. This is the sum total of all the weak atomic waste that was generated in the Federal Republic during this period. Research was stopped in 1995; between 1995 and 2004 cavinates were filled with salt. This is a brief timeline of Asse II’s history.

The current problem that Germany is facing goes beyond that. In 1965 the Asse-II mine was turned into a temporary storage, but as the development of nuclear energy boomed, the mine became a permanent disposal site for nuclear material. And now, water filtrations and poor maintenance also means the mine is unstable and in danger of collapsing.

A worker reopens a 120-metre tunnel of the Asse nuclear waste disposal. Source: daylife

Asse II is not the only mine used for this purposes. Salt mines are common in the Lower Saxony area, and they became very useful in the 60s for the eternal problem of atomic energy: to find a safe place to store the waste, as nuclear waste remain active for thousands of years. The Asse II mine was originally a commercially used mine with a large number of galleries and excavation chambers in which salt was mined up to the overlying and adjoining rock leading up to the groundwater. These galleries are the spaces where currently all the waste is storaged. Due to water filtrations, the hill has moved six meters from the seventies until today, as Laura Lucchini reports. That’s why now there’s an urgency to find a new place for this waste.

There are two interesting things about this. With all these background on danger and water filtration, we want to think on other possibilities for “underground architecture”, infrastructures or subterra, now that the mine is unstable and filling with water. And, in the other hand, we can speculate on new places for waste storage. If radioactivity diminishes over time, so in principle the waste needs to be isolated for a period of time until it no longer poses a hazard. This can mean hours to years for some common medical or industrial radioactive wastes, or thousands of years for high-level wastes.

Nuclear-Waste Pileup. Photograph by Emory Kristof, National Geographic

Salty Cave. Photograph by Tobias Schwarz, Source

On a document written by the International Atomic Energy Agency, we can read:

The process of selecting appropriate deep final repositories for high level waste and spent fuel is now under way in several countries. The basic concept is to locate a large, stable geologic formation and use mining technology to excavate a tunnel, or large-bore tunnel boring machines to drill a shaft 500–1,000 meters below the surface where rooms or vaults can be excavated for disposal of high-level radioactive waste. The goal is to permanently isolate nuclear waste from the human environment.

Which are the possibilities to use this underground city in a proper way? Maybe not too long in our forthcoming future, we’re going to be capable to develope projects in which buildings become an ecosystem in itself, completely embedded in the context that surrounds it, as Wen Ying Teh proposed. What would nature do to create a new type of hybrid ecology where industry and endemic wildlife can not only co-exist but also be mutually beneficial?

What if the solution for re-using the underground architecture of mines goes beyond the word “re-using”?
What if we just leave nature to do its work?

According to that, we can go further from geological disposal, and think about sea-based options for disposal of radioactive waste. It can include burial beneath a stable abyssal plain, burial in a subduction zone that would slowly carry the waste downward into the Earth’s mantle, and burial beneath a remote natural or human-made island. Kenneth Dillon pointed that the enormous volume of water in the world’s oceans also has a vastly greater dilutive capacity than any single land site in the event of unintended leaks and then he adds, that seawater itself contains a variety of radionuclides, so treating it as a domain in which there is no natural radioactivity runs counter to fact.

MAD’s Super Star

These approaches are currently not being seriously considered because of technical considerations and legal barriers in the Law of the Sea. In 2001 the Plutonium Memorial Competition was seeking solutions to the problem of plutonium disposal. The Bulletin for Atomic Scientists called on artist, architects and visionary thinkers to enter a competition to design it. As they said, the memorial is to provide safe storage for the world’s plutonium for eternity, a place “where tourists can visit” that is “beautiful and grand and awe inspiring”. We participated on the competition [team with architect Claudio Pirillo, unfortunatelly hard drive with all our 2000-2001 work collapsed] and proposed to place a star in the middle of the ocean, as a sea-based disposal and as a huge floating monument at the same time. The closer current image to our proposal is MAD‘s Super Star, that looks as a perfect place to have a sea-based waste disposal.

The winning entry was Mike & Maaike proposal 24110, called like that because it takes 24,110 years for spent nuclear fuel to reach its half-life. The project is located south of the White House in Washington D.C. The siting turns upside down two scared ideologies: the out-of-sight and the great American lawn cover-up. But Engler points “Humorous and witty, it states that sweeping the issue under the carpet is no longer an option“.

Mike&Miaake 24110 proposal

As Mira Englers wrote: “The difficulties and paradoxes raised by waste have forced us to rethink ethics and aesthetics“.

Mike Simonian once said that the length of time that plutonium must be sealed away from our air, land, and water defies the durability of every material and structure conceivable by man, quickly revealing that what we call a permanent solution, is actually an unforgivable gift to future generations. 24,110 is the half-life of plutonium [in years]. And we ask, Do we want to live surrounded by floating stars or hiding on the bowels of a mountain? Which kind of new waste landscape we will generate if we don’t change our consumption system?

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