Sustainability at FortumCase: Responsible final disposal of nuclear waste – final disposal begins in Finland, the first in the world
Nuclear waste management
Waste management at the Loviisa power plant has been divided into two sectors. Conventional waste management covers waste which does not contain activity, while waste formed in the controlled area is handled as radioactive waste. Waste in controlled area is divided into three groups by mode of generation and original use: low-level waste (conventional maintenance waste), medium-level waste (liquid waste) and high-level waste (spent fuel).
According to Finnish legislation, nuclear waste generated in Finland must be finally disposed of in Finland, and the power plant companies are responsible for their respective nuclear waste management. Swedish legislation is similar in regard to responsibilities. The final disposal solutions for the nuclear waste of the Loviisa nuclear power plant and Fortum's co-owned nuclear power plants in Finland and Sweden are among the leading solutions in the world.
Waste created in nuclear power plant operations is governed by either regular (non-radioactive) or radioactive waste management rules. Regular waste is the waste created in a typical work environment, in goods transport, office tasks and cafeteria operations, for example. Radioactive waste is classified as either low-level, intermediate-level or high-level waste, based on how it was created, its original purpose and radioactivity level. At Fortum's Loviisa nuclear power plant, low-level and intermediate-level waste are finally disposed of in a 110-metre-deep cave that has been excavated in the Hästholmen bedrock in Loviisa.
Nuclear waste management
What happens to spent nuclear fuel?
Nuclear power plants produce electricity using uranium as fuel. The energy in uranium is in a tightly compressed format, so the amount of spent fuel is small. Spent nuclear fuel is radioactive. Therefore, it must be kept isolated until its radioactivity has decreased to a harmless level. This isolation is called final disposal.
Posiva, founded and owned by Fortum and another Finnish nuclear operator, TVO, takes care of the final nuclear waste disposal of their nuclear power plants. The plan is to dispose of high-level nuclear waste in the final repository of Posiva in Olkiluoto, in the municipality of Eurajoki. The final repository and related encapsulation unit are expected to be ready for use in 2020.
The Finnish Government granted in November 2015 a licence to Posiva for the construction of a final disposal facility for spent nuclear fuel. After extensive and multidisciplinary research and development work, Posiva can now proceed with construction of the final disposal facility in Olkiluoto according to the concept it has developed. The final disposal of the spent fuel generated in the Olkiluoto and Loviisa nuclear power plants into the Finnish bedrock is planned to start in the early 2020s.
SKB (Svensk Kärnbränslehantering AB) is responsible for managing the waste created by Fortum's co-owned nuclear power production in Sweden. A final repository for spent nuclear fuel is being built in Forsmark, in the municipality of Östhammar. The plan is to complete the construction by the end of this decade. After construction and the pilot period, final disposal can begin at the end of the next decade.
Who is responsible for nuclear waste?
In Finland, the law stipulates that each producer of nuclear power-generated electricity is responsible for its own nuclear waste management. Fortum Power and Heat Oy and Teollisuuden Voima Oyj have established Posiva Oy to manage the research and development work required for the disposal of the spent nuclear fuel produced at their power plants as well as the implementation of the selected disposal solution.
The Ministry of Employment and the Economy holds the highest power of control and supervision over nuclear waste management in Finland. The Ministry prepares the legislation concerning nuclear waste as well as any associated international agreements with regard to Finland. It also supervises adherence to the legislation and agreements.
The Radiation and Nuclear Safety Authority (STUK) supervises the safety of nuclear power generation. STUK prepares instructions and regulations on nuclear safety and inspects the safety of the power plants. The safety aspects of nuclear waste processing and storage also fall within the scope of STUK's supervision activities.
What are the responsibilities in final disposal?
The processing of nuclear waste is governed by the Nuclear Energy Act, the Nuclear Energy Decree, and a Government Decree. Amended in 1994, the Nuclear Energy Act stipulates that all spent nuclear fuel produced in Finland must be disposed of in the Finnish bedrock. The same legislation also prohibits the import, and disposal of, foreign nuclear waste in Finland.
The Government Decree on the safety of the final disposal of nuclear waste stipulates the following concerning the long-term radiation effects of final disposal: “The annual dose of the persons with the greatest exposure shall remain below 0.1 mSv (millisieverts), and the average annual doses of other persons shall remain insignificant.”
With regard to the management of radioactive substances, Fortum always strives to keep any emissions well below both the emission limits set by the authorities and Fortum's own target limits, which are more stringent than the official limits.
How was the site for final disposal chosen?
The disposal solution is the result of decades of research and development work aimed at developing a safe solution for the permanent isolation of nuclear waste.
The Olkiluoto island was chosen as the site of the repository from among many survey sites on the basis of location surveys and safety assessments carried out between 1987 and 2000. The underground research facility ONKALO, which Posiva started to construct in 2004, has enabled research at the actual disposal depth. The aim has been to preserve the good characteristics of the rock as far as possible in the construction phase of the underground research facility.
The research carried out during the construction has confirmed earlier assumptions about the rock properties. Based on the research, it is now known that there are few cracks in the bedrock at the disposal depth the bedrock is stable at a depth of hundreds of meters, the roundwater is oxygen-free the groundwater flow is minimal.
The safety of final disposal is supported with information obtained through research. The bedrock, the materials used in the disposal process, and the functionality of the technical solutions are subjected to safety studies.
An extensive body of assessment documentation, known as the safety case, is prepared to prove the safety of final disposal. The most central part of the safety case is scenario analysis whereby the behavior of the final disposal system installed deep in bedrock is assessed on the basis of postulated event sequences. The temporal scopes of the analyses stretch far into the future, and they consider factors such as climate change and the formation of a thick glacier as well as associated rock movement.
Further proof of the safety of final disposal for the safety case may be gathered by observing so-called natural analogs—in other words, by making comparisons with nature.
Natural analogs are examples, observed around the world, of how naturally occurring materials have behaved under different conditions over long periods of time. By studying nature, it is possible to establish how copper, clay, and radioactive substances behave under different conditions over long periods of time. This has led to a better understanding of the representativeness of the models used to describe the functionality of the disposal system.
It is now known, for example, that clay has effectively stopped the migration of uranium as well as other radioactive substances from a radioactive uranium deposit deep in the bedrock in Cigar Lake, northern Canada. No radiation levels differing from the normal natural background radiation levels can be observed above ground in the area.
Furthermore, natural copper formations found around the world have persisted for up to millions of years, which can be considered as proof of the long-term strength of copper canisters placed deep in the bedrock. In Hyrkkölä in southern Finland, for example, copper occurs in its original form in granite rocks despite having been exposed to groundwater containing sulfide under oxidizing conditions.
Who pays for the costs of disposal?
Companies with a nuclear waste management obligation prepare for the costs by collecting funds in advance in the price of electricity and depositing them in a specific fund. This provides society with a financial guarantee for the handling of nuclear waste management under all circumstances.
The Finnish State Nuclear Waste Management Fund was established in 1988 in accordance with the Nuclear Energy Act. Separate from the state budget, the fund is controlled by the Ministry of Employment and the Economy. The purpose of the fund is to collect, preserve, and safely invest the funds required for the management of nuclear waste in the future.
The fund's capital consists of annual payments by the companies with a nuclear waste management obligation as well as the fund's revenue. The Ministry makes annual decisions on the amount of cost liability at the current price level on the basis of reports submitted by the companies with a nuclear waste management obligation. The total amount of collected funds must, at any given time, correspond to the costs of nuclear waste management activities not yet implemented.
Nuclear waste management payments collected in the fund also cover any research and development costs and the costs incurred from official supervision and administrative activities.