The Swedish government approves the construction of a spent nuclear fuel repository
At the end of January, the Swedish government gave the radioactive waste company Svensk Kärnbränslehantering AB (SKB) the green light to proceed with a deep geological repository (DGR) for spent nuclear fuel (SNF) at a location near Vattenfall’s 3.2-GW nuclear power plant in Forsmark.
The milestone, which completes a planning process that has taken more than 40 years, makes Sweden the only other country, after Finland, to take active steps to build a permanent SNF repository.
SKB, a company founded in the 1970s by Sweden’s nuclear power plant, will now apply for a permit from the Land and Environment Court and the Swedish Radiation Safety Authority. The units are expected to “establish conditions” for the integrated facility of $ 2 billion (SEK 19 billion) which will include a DGR at Forsmark in Östhammar municipality and an encapsulation facility next to an intermediate warehouse in Clab, outside Oskarshamn municipality.
Clab currently contains approximately 6,500 tonnes of SNF and SKB has proposed that when Sweden’s 12 nuclear reactors retire, its SNF storage needs will increase to accommodate 12,000 tonnes.
A complex endeavor
SKB envisages that when DGR is “fully built” at Söderviken (within Forsmark’s industrial zone) “sometime in the 2080s”, it will contain 60 kilometers of tunnels with space for 6,000 copper canisters that hold up to 12,000 tonnes of SNF. – The total volume of the space required underground in the rock will be about four square kilometers, says SKB. The project also plans to increase the capacity at Clab from 8,000 tonnes of SNF to 11,000 tonnes.
1. This photomontage shows the final deep repository for 12,000 tonnes of spent nuclear fuel in Forsmark, Sweden. The total length of the tunnel system is more than 60 kilometers. Underground, the repository covers three to four square kilometers at a depth of 500 meters. With permission: SKB |
DGR’s construction is coming consists of two parts: an area of operation on the ground surface and a landfill area underground (Figure 1). The underground facility will require drilling of several tunnels, 300 meters long, to depths up to 500 meters. – Eight meter deep deposition holes are drilled at six meter intervals in the tunnel floors, says SKB.
The facility will use SKB’s developed KBS-3 containment method. The capsules, each 5 meters long and weighing up to 27 tons, will consist of a copper shell and a insert of ductile iron. Capsules will be deposited in deposition holes surrounded by the bentonite buffer and the bedrock.
“Construction of the tunnel system and deposition of canisters in the Nuclear Fuel Repository will take place in parallel for many years in separate business areas. When all deposition holes in a deposition tunnel are full, the tunnel is backfilled with clay. Finally, when all canisters are deposited, the entire repository is refilled, says SKB. But “Only when all licenses are in place can the construction start, after which time it will take about 10 years to build the repository for spent fuel”, it was noted.
Decades of development
The Government’s approval stems from efforts that began in 1977 with geological surveys of Sweden’s bedrock. In 1992, a site selection process was initiated via a voluntary response. In 2009, after five years of site investigations, SKB chose Forsmark and submitted a permit application for the proposed site and the containment method KBS-3 to the government in 2011. More notable milestones came in January 2018 and October 2020, when the municipalities of Oskarshamn and Östhammar voted to approve the repository.
Sweden’s nuclear power producers have emphasized the importance of building DGR. In May 2021, they reportedly sent an urgent message via the Nord Pool electricity exchange that Clab’s interim facility had reached full capacity. Sweden’s nuclear power fleet currently comprises six reactors in operation, which generate almost 30% of the country’s power. The state-owned power plant Vattenfall co-owns five units, including Forsmark 1, 2 and 3, and Ringhals 3 and 4, while Oskarshamns Kraftgrupp (OKG) owns the sixth, Oskarshamn-3. While Vattenfall claims to have invested in “comprehensive” modernization programs and expects its reactors to be “well prepared to operate for decades to come”, it was warned in May last year that without a long-term disposal solution, the Forsmark 4 reactor faces potential shutdown 2024. followed by Forsmark 3 and Ringhals 3 and 4 next year, with Forsmark 1 2028.
Solna’s head office SKB is primarily owned by Vattenfall (36%), followed by Forsmarks Kraftgrupp (30%), OKG (22%) and Sydkraft Nuclear Power (12%). In another statement FORCE in January, SKB’s CEO Johan Dasht praised the project as a potentially groundbreaking opportunity for the long-standing issue of SNF waste management. – For SKB, the decision further strengthens our position as a world leader in this area, he says.
2. Teollisuuden Voima Oyj (TVO), operator of the Olkiluoto nuclear power plant with two units of 3.4 GW, is ready to start Olkiluoto 3 at the end of February. When the long-delayed 1.6-GW EPR reactor officially starts operating in July 2022, the island of Olkiluoto will generate about 30% of Finland’s energy. With permission: TVO |
Finland ready to conduct final disposal trials by 2023
According to Washington, DC-based Stimson Centera non-profit organization committed to international security, closely monitoring global SNF waste management, of 21 countries that have significant nuclear fuel activities and spent fuel management policies, five countries – Canada, Finland, France, Sweden and Switzerland – are the most advanced “to move forward with deep geological disposal in the coming decades.”
Nevertheless, Finland is above all the only country that is already building a DGR, and will start construction of its Onkalo facility in Olkiluoto (Figure 2), off the southwest coast of Finland in 2016. Finland expects to start operating the facility in 2025. Onkalo will also use SKB’s KBS-3 final disposal concept for storing SNF up to 450 meters underground at a site chosen by Posiva, SKB’s Finnish equivalent, and licensed in 2015 – which is the first time a building license for a geological disposal facility was obtained anywhere in the world.
Posiva, which at the end of December submitted an operating license for its integrated DGR and encapsulation plant, announced in January in particular that they are ready to carry out a final disposal test run (TRFD) 2023. “TRFD covers the entire final disposal disposal process. Disposal systems and machinery , organization and procedures, but will be performed with dummy fuel assemblies, ”the company said FORCE.
Tiina Jalonen, senior vice president of development for Posiva, suggested that the key to the development of the final disposal “is the long-term safety of the solution”, which must be “assessed and demonstrated with the safety case.” The safety case covers all aspects of the investigation, including all technical and scientific material, analyzes, observations, experiments, tests and other evidence used to justify the reliability of the assessments made of the long-term safety of final disposal. “The more than four decades of research work are transformed into a detailed description of the geological disposal solution, which analyzes different evolutionary paths and shows the safety of disposal in the conditions in Olkiluoto’s bedrock,” she said.
A social license to work
According to the Stimson Center, as well as Finland and Sweden, Canada, France and Switzerland are making progress in this regard. In France, the Agency for the Management of Radioactive Waste is currently preparing a license application for its planned DGR, “Cigéo, “ with construction starting as early as 2023. In Canada’s and Switzerland’s national waste management agencies are examining suitable sites through site characterization.
As of 2021, nine countries – Belgium, the Czech Republic, Finland, France, Germany, Japan, South Korea, Sweden and Switzerland – had underground research laboratories (URLs), of which three web addresses (in Finland, France and Germany)) are site-specific. China is currently building a site-specific URL in Gansu Province.
Stimson suggests that “trust” – the perceived credibility and legitimacy of an active body – is absolutely necessary to obtain a much-needed “social license to operate” (SLO). Finland and Sweden have so far found success in communicating trust and security to communities that are already closely involved in the nuclear fuel cycle. “In the 5 countries with the most advanced DGR plans, community involvement is a long-term and dedicated effort that has continued for decades based on the understanding that public acceptance is crucial to the success of such facilities,” Stimson added. “The public has been involved in many aspects of repository plans, particularly those using community-based, consent-based localization processes.”
–Sonal Patel is POWER senior associate editor (@sonalcpatel, @POWERmagazine).