For Switzerland, the decision is clear: the radioactive waste must be disposed of deep underground.
But hold on: are there really no better options?
How the deep geological repository works
People often ask about alternatives to deep geological disposal. A particularly popular suggestion on social media involves blasting radioactive waste into space. True to the motto: out of sight, out of mind. But would it be a good idea?
The answer to this – and eight other (purported) alternatives to a deep geological repository:
Many countries favoured ocean dumping as a particularly cost-effective waste disposal solution and practised this method for many years. Even Switzerland dumped radioactive waste into the sea, specifically in the North Atlantic. The Organisation for Economic Co-operation and Development, OECD, set up an international monitoring programme there but did not detect increased rates of radiation exposure.
The flipside
Our oceans contain billions of tonnes of natural radioactive substances. They are so diluted that their radioactivity poses no danger. Nevertheless, ocean dumping was banned in 1993 (with a few exceptions).
The main reason for this is the so-called tragedy of the commons, which describes the excessive and uncontrolled use of resources – in this case, marine resources. Contamination would ultimately harm everyone – humans and the environment.
According to the International Atomic Energy Agency (IAEA), around 392,000 tonnes of high-level waste were produced up to 2016. One of the most powerful launch vehicles ever built was Saturn V. Based on its load capacity of 133 tonnes, almost 2,950 rocket launches would be required to shoot the high-level waste into Earth’s orbit. Starting with Sputnik 1 in 1957, around 4,300 rocket launches have been carried out worldwide. The vast majority of these rockets had a much smaller load capacity than Saturn V. This causes a number of problems.
Problem 1: The success rate of all rocket launches is just under 90 per cent. 295 launches of rockets filled with radioactive waste would have failed and, in some cases, even exploded. Radioactive rain? A bleak prospect.
Problem 2: The load capacity is only calculated for the rockets to reach Earth’s orbit. However, that would not be far enough, as the waste could potentially fall back to Earth or collide with satellites. For this alternative to work, we would need much more powerful rockets – or many more rockets.
Problem 3: The costs per rocket launch vary greatly. At 50 million US dollars per launch, Elon Musk’s Starship rockets are almost a bargain. NASA’s rocket launches, in contrast, are sometimes quoted to cost up to 2 billion US dollars. Since we intend to go into serial production, we will base our calculation on the best-case benchmark of 50 million US dollars: 2,950 times 50 million equals 147.5 billion US dollars. This handsome sum is based on the most cost-effective scenario and does not even include decommissioning, interim storage or transport to the space centres. Not to mention: this solution only considers high-level waste, which brings us to Problem 4:
Problem 4: All low- and intermediate-level waste – and there is much more of it than high-level waste – will be left on our planet. This means that we would by no means have solved the problem entirely.
Another idea centres on channelling the waste into even greater depths: similar to a conveyor belt, radioactive waste would be transported into a subduction zone in the earth’s interior. Subduction zones form when tectonic plates collide and gravity causes the heavier of the two plates to descend beneath the ocean floor, creating a trench in the earth’s crust.
This project would be far too risky as processes occurring in subduction zones cannot be controlled. It would be impossible to estimate whether, when and where radioactive substances could resurface. These zones are also exposed to earthquakes and volcanic activity, which does not make matters easier (see Idea # 5).
In the 1950s, the German physicist Bernhard Philberth came up with the idea of an aerial drop of radioactive waste over Greenland or Antarctica. The landing impact would initially cause the “waste bombs” to sink into the ice. The residual heat of the waste would then finish the job by melting the ice, allowing the radioactive waste to penetrate into greater depth. Germany’s nuclear safety ministry took a dim view of Philberth’s idea, not least because he conveyed a certain fanaticism.
Climate change in particular has shown that there is nothing eternal about the “eternal ice”. In addition, it constantly drifts. For this reason, the United States had to abandon its “Camp Century” in Greenland in 1967. As part of the so-called Project Iceworm, launch bases for nuclear missiles were to be constructed there – and a nuclear reactor was to supply the necessary energy. The Americans took the nuclear reactor back home, but left the radioactive waste behind. As ice is melting at an accelerated rate, this waste now threatens to reach the surface and the Arctic Ocean.
Radioactivity cannot simply be incinerated. When dumped into a volcano, the waste would probably melt in the magma. What would happen in the event of an eruption is clear: the radioactive particles would be propelled into the air with the volcanic ash, spread over large areas and come down in the form of radioactive ash fall. The consequences would be devastating.
This method is still being researched and was initially also considered by Switzerland, but then rejected in the 1980s. While the drilling technology is well advanced, the diameter of the borehole at great depth is limited. Thick-walled disposal canisters, such as those required in Switzerland to enclose high-level waste, would not be able to fit into the boreholes.
Other questions also remain unresolved, for example heat development, detection of water-bearing fissures or long-term behaviour. In general, depths of four to five kilometres are relatively unexplored. Last but not least, we would not be in a position to ensure the retrievability of the waste – which is required by law in Switzerland.
In the hope that future technologies will offer a better solution (see Idea # 9), the waste could also be held in the interim storage facilities for an indefinite length of time. This option is worrying for two reasons: on the one hand, storing waste at the surface is not safe in the long term due to risks connected with natural disasters, erosion or human-driven events such as war. On the other hand, it is morally questionable to postpone resolving the waste disposal issue and burdening future generation with this task.
In principle, the same arguments apply here as for Idea # 7. However, instead of waiting for better solutions, the waste is simply left to its own devices, some of it even out in the open. It is impossible to predict today what society will be like 100 or 2,000 years from now. Deep below ground, time essentially comes to a standstill. Change occurs at a very slow rate, which is why a deep geological repository also provides passive safety, i.e. it can remain safe without the need for human intervention.
The open storage of radioactive waste is prohibited in Western Europe. This idea is evidently problematic: disposal canisters corrode more quickly when exposed to the elements. They are also vulnerable to external impacts such as aircraft crashes, terrorist activities and natural disasters. One city that stores waste at the surface is Seversk in Siberia. It is off-limits to non-residents and harbours, among other things, radioactive waste from France, as revealed in 2009 in the Arte documentary “Waste: The Nuclear Nightmare”. The waste will not remain safe forever. The nuclear disaster at Chernobyl showed how much damage can be caused by the release of radioactivity.
Transmutation is being researched worldwide. To date, no industrially mature transmutation reactor exists and the technology is banned in Switzerland under current legislation.
Transmutation can reduce the longevity of high-level waste. That sounds promising at first. However, a transmutation reactor also generates radioactive waste. In addition, low- and intermediate-level waste – which makes up the majority of our waste – cannot be transmuted.
A deep geological repository will still be needed
There is an international consensus that deep geological disposal is the best approach to protect humans and the environment from radioactive waste in the long term.
Many alternatives have been proposed and researched. However, they are either not safe enough, impossible to implement or have not yet been fully developed. Waiting is not a solution. In Switzerland, we have developed a robust concept and have identified an ideal host rock and the best site for a deep geological repository.
We are therefore in a position to solve the problem now, without burdening future generations with this issue.
Images: iStock / ZWILAG / Nagra
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