The take away

• The world’s first final repository for spent nuclear fuel, is being built in Finland, with 42 km of tunnels being carved from granite, designed to survive for 100,000 years.
• The bacteria research may have important implications for deep storage.

The discovery of radiation-eating bacteria could add another tool to the arsenal of scientists trying to protect future generations from toxic nuclear waste. Last spring, researchers from the University of Manchester reported that certain microbes can survive in containment facility conditions and even use substances like uranium instead of oxygen, converting it into an insoluble form that is less likely to seep into the environment.

Repository for spent nuclear fuel

42 km of tunnels: Onkalo in Finland is the world’s first final repository for radioactive waste.

Currently, the world’s low- to high-level radioactive waste is kept in above-ground storage facilities. But this is “too risky for the long term”, says Walter Tromm, nuclear waste management expert at the Karlsruhe Institute of Technology. “Dangers include terrorist attacks and airplane crashes, as well as floods and other natural disasters.” The safest long-term solution seems to be entombing nuclear waste 400–700 metres underground.

Onkalo, the world’s first final repository for spent nuclear fuel, is being built in Finland, with 42 km of tunnels being carved from granite, designed to survive for 100,000 years. Even though radioactivity from high level waste drops sharply within the first 1,000 years, it takes many more millennia to be fully safe, leaving future civilisations unlikely to be aware of what lies under their feet.

Tromm believes the bacteria research may have important implications for deep storage. “It could be an additional safety margin if the bacteria can prevent chemical complexes from forming and escaping.” Onkalo’s first cast iron and copper-wrapped nuclear waste should be laid to rest in the early 2020s, with its construction and operation until 2120 costing €3.5 billion. In the meantime, exploration is underway to find suitable rock formations that can host other European countries’ nuclear waste.

Essentials for entombing nuclear waste:

• Mark as a dangerous site to warn future civilisations
• Protect against climate change and future ice ages
• Prevent leakage from storage casks and facility interiors
• Make repositories so hard to access that security is no issue