Sweden advances with billion-dollar nuclear waste repository

Sweden recently began constructing a final facility for storing spent nuclear fuel. The aim is to safely store highly radioactive waste for an extended period, with scientists projecting it could remain stored for up to 100,000 years. Construction work has already commenced in Söderviken, near the Forsmark nuclear power plant in Sweden.

The repository, located 500 metres underground in solid rock, will be the second such facility globally. Burial in stable rock will provide long-term isolation and safety for the highly radioactive waste. The repository will be set in rock that is 1.9 billion years old. The Swedish Nuclear Fuel and Waste Management Company (SKB) reports that about 12,000 tonnes of spent nuclear fuel will be placed in the repository.

The nuclear industry has long struggled with the challenge of safely disposing of waste known for its long-lasting radioactivity, which persists for millennia. For this reason, safe storage is crucial because of the various risks, including harm to human health and the contamination of soil, water, and air.

The World Nuclear Association estimates that about 330,000 tonnes of spent nuclear fuel worldwide require proper disposal. However, most spent fuel is currently stored in temporary storage pools at reactors, posing potential long-term risks.

The issue of nuclear waste disposal is likely to intensify with the expansion of nuclear energy as part of the energy transition. Many countries, especially in Europe, are already planning the construction of new nuclear reactors. Currently, Finland is a leader in developing a permanent deep geological repository for highly radioactive nuclear waste.

The Forsmark repository is expected to begin receiving waste in the late 2030s, with construction and securing completion planned around 2080. The repository will cover a 60-kilometre network of tunnels placed deep inside the ancient rock.

Spent nuclear fuel will be placed inside 5-metre copper capsules designed to be corrosion-resistant. Sweden plans to place 6,000 such containers there. These capsules will then be further secured by placing them in clay before final burial.

The estimated cost of building the Forsmark repository is 12 billion kronor (approximately 1.55 billion Canadian dollars). Its long-term nature stems from the high level of complexity and precise safety requirements for storing nuclear waste. The project will require the removal of about 2.3 million cubic metres of rock. Specially designed machines will be responsible for placing the capsules with spent fuel inside the repository.

The repository will be constructed in stages. While the capsules with spent fuel are placed in completed tunnels, new ones will be excavated simultaneously. This process is expected to continue for about 40 years until all spent nuclear fuel has been safely stored. Afterward, the entire facility will be permanently sealed.

The project faces opposition and is simultaneously regarded as a significant step towards responsible nuclear waste management. Environmental groups express concerns about the long-term safety of the repository, highlighting the potential risk of groundwater contamination. Reuters reports that a Swedish non-governmental organization has filed a court appeal, demanding additional safety assessments for the Forsmark repository.

Additionally, research conducted by the Royal Institute of Technology suggests potential issues with the corrosion of copper capsules, raising concerns about the possibility of radioactive leaks into groundwater.