Onkalo – the world’s first permanent nuclear waste repository
Onkalo is a Finnish word for hiding place. It is situated at Olkiluoto in Finland - approx. 300 km northwest of Helsinki and it's the world's first attempt at a permanent repository. It is a huge system of underground tunnels hewn out of solid bedrock. Work on the concept behind the facility commenced in 1970s and the repository is expected to be backfilled and decommissioned in the 2100s – more than a century from now. No person working on the facility today will live to see it completed. The Finnish and Swedish Nuclear Authorities are collaborating on the project, and Sweden is planning a similar facility, but has not begun the actual construction of it.
Onkalo presentation folder
Facts about nuclear waste
High-level nuclear waste is the inevitable end result of nuclear energy production. The waste will remain radioactive and/or radiotoxic for at least 100 000 years. It is estimated that the total amount of high-level nuclear waste in the world today is between 250 000 and 300 000 tons. The amount of waste increases daily.
Radioactive waste is hazardous to all living organisms and exposure to radiation may result in death, incurable disease, as well as mutation of the genetic code. The security standards are based on theoretical assumptions, as humanity has no previous experience to build on with regards to radioactive waste. In Europe there is a security standard of 100 000 years for the min. period that the waste must remain isolated from all living organisms. In the US it is 1 000 000 years.
A hundred thousand years
It is difficult for human beings to understand time spans beyond a few generations, let alone thousands of years. To put time into perspective, we need milestones:
The human species as we know it today is believed to have existed for approx. 100 000 years. The oldest cave paintings, known today, are approx. 30 000 years old, the pyramids approx. 4 500 years old, the Birth of Christ, 2010 years ago, the detection of radiation approx. 115 years ago.
Spent nuclear fuel is normally kept in water pools in interim storages. Almost all interim storages are on the ground surface, where they are vulnerable to natural or man-made disasters, and extensive surveillance, security management, and maintenance is required. The water in the pools cools the fuel rods, as the heat emanating from them may otherwise result in radioactive fire, and at the same time, water creates a shield for radioactivity. It takes 40 – 60 years to cool the fuel rods down to a temperature below 100 degrees Celsius. Only below this temperature may the spent fuel be handled or processed further. Most interim storages are situated near nuclear power plants, as the transportation of waste is complicated, and subject to extensive security issues.
To ensure that the waste is kept isolated from all living organisms and does not spill into nature, permanent storages are needed, as we cannot ensure continuous surveillance, security management, or maintenance of interim storage for the duration of the security standard period of 100 000 (EU) to 1 000 000 (US) years.
Permanent waste storages must be located in very stable environments. Areas with volcanic or seismic activity are ruled out, as are lowlands that are subject to potential flooding or rising sea levels, eroded or porous bedrock where ground water leaks may occur. Nuclear energy producing countries without suitable sites for permanent storages may have to export their waste to other countries. Transportation safety is crucial, but an unsolved question.
Spent nuclear fuel may be reprocessed as only a fraction of the energy in the fuel rods are used, before they are moved from the reactors to the interim storage. Plutonium is a bi-product of reprocessing. Plutonium is a vital ingredient in nuclear bombs. It is a political decision and a consequence of the non-proliferation act, that reprocessing is not carried out today. If reprocessing is later practised, spent nuclear fuel will remain in interim storage. The amount of high-level nuclear waste may be reduced, but not avoided through reprocessing.
Research is carried out into the possibility of transmutation, which is a process that may reduce the toxicity of the waste and time span in which it will be dangerous. So far, transmutation is a theoretical option only, that scientists have conceived, but not yet been able to try out in reality. If transmutation becomes a reality, the amount of high-level nuclear waste may be reduced, but not avoided.
Most ancient language have been forgotten over time, and have had to be rediscovered to be understood by us in present time. Some languages we have yet to decode. It is an open question if and how we can communicate with an unknown and very distant future about complicated issues like nuclear waste and radiation. Scientific studies have been conducted in relation to nuclear waste storages, but the studies were ended as the US Academy of Science deemed it impossible to secure communication with any scientific certainty over a period of 100 000 years.