Sweden has damaged floor on its closing repository for spent nuclear gas (SNF)—a milestone reached after 40 years of analysis and improvement—making it the world’s second deep geological repository (DGR) now beneath development.
Svensk Kärnbränslehantering AB (SKB), a nuclear gas and waste administration firm owned by Sweden’s nuclear operators, formally introduced the beginning of development for the DGR at Forsmark, Östhammar Municipality, close to Vattenfall’s 3.2-GW Forsmark nuclear energy plant, on Jan. 15. The milestone kicks off a 10-year development interval for the Swedish Spent Gas Repository. “The ultimate repository shall be prepared for disposal within the 2030s and shall be totally prolonged within the 2080s,” the corporate famous.
The ultimate repository is envisioned as an enormous underground mission that can bore 500 meters deep in rock that’s 1.9 billion years outdated. When accomplished, it can retailer 12,000 tonnes of SNF in 6,000 copper canisters, shielded by bentonite and positioned alongside 60 kilometers of tunnels. The floor part will cowl a complete space of 24 hectares—“the equal of 44 soccer fields,” SKB mentioned.
Groundbreaking entails “the beginning of two years of preparatory work above floor, together with the development of a rock mass storage and water remedy plant, a bridge over the cooling water canal and forest clearing,” SKB mentioned. “After that, work begins to go down into the bedrock.”
A Milestone 40 Years within the Making
The milestone is a significant triumph for SKB, which is owned 36% by Vattenfall AB, 30% by Forsmarks Kraftgrupp AB, 22% by OKG Aktiebolag, and 12% by Sydkraft Nuclear Energy AB. The corporate was based after analysis initiated by the Swedish authorities relating to the dealing with and closing disposal of radioactive waste began on a big scale in 1975. The nation intensified its analysis by means of the industry-led Nuclear Energy Security (KBS) mission, resulting in the usage of the KBS-1 and KBS-2 strategies, and finally, in 1980, the KBS-3 technique, which emphasised the usage of DGRs inside crystalline bedrock for the long-term containment of SNF.
In 1992, a web site choice course of was initiated through a voluntary response strategy. In 2009, after 5 years of web site investigations, SKB chosen Forsmark, submitting a license software for the proposed web site and the KBS-3 containment technique to the federal government in 2011. Extra notable milestones got here in January 2018 and October 2020, when the municipalities of Oskarshamn and Östhammar voted to approve the repository. In January 2022, Sweden’s authorities gave SKB the inexperienced gentle to proceed with the DGR
Swedish nuclear operators have remained constantly supportive of the mission, warning that interim storage capability won’t be sufficient in the long term. Sweden’s nuclear fleet presently contains six working reactors, which generate almost 30% of the nation’s energy with a mixed capability of seven GW. State-owned utility Vattenfall co-owns 5 items, together with Forsmark 1, 2, and three, and Ringhals 3 and 4, whereas Oskarshamns Kraftgrupp (OKG) owns the sixth, Oskarshamn-3.
Following a landmark change in its vitality coverage in June 2023—from a goal of 100% renewable electrical energy by 2040 to 100% fossil-free electrical energy—the Swedish authorities introduced an bold roadmap for nuclear energy. By 2035, Sweden plans to assemble two large-scale reactors, every with a capability of 1,250 MWe. Past this, the federal government goals to deploy the equal of ten further reactors, together with small modular reactors (SMRs), by 2045. Key tasks embody Vattenfall’s plans to construct new capability at Ringhals, with deployment anticipated within the early 2030s, and feasibility research for SMRs at each Ringhals and Oskarshamn, spearheaded by Vattenfall, Fortum, and different companions.
The renewed give attention to nuclear vitality is supported by legislative modifications, which have moved to take away a cap on the entire variety of reactors and develop allowable development websites past current nuclear amenities. “The background to this reversal might be defined by rising local weather consciousness, a cumbersome geopolitical state of affairs, elevated technical challenges associated to the electrical energy system, and a extra strained nationwide economic system the place its hyperlink to the electrical energy value has turn into more and more clear,” a current report from the nationwide nuclear coordinator reads.
Sweden’s nuclear crops depend on the CLAB repository close to Oskarshamn as their sole interim storage facility for spent nuclear gas. Operational since 1985, CLAB shops used gas underwater in a granite cavern to permit for cooling and discount of radioactivity. Initially designed for five,000 tonnes, its capability has been expanded to 11,000 tonnes to accommodate all gas from Sweden’s reactors. Spent gas stays in CLAB for 40–50 years earlier than being encapsulated in copper canisters for closing disposal within the deliberate Forsmark repository.
Finland’s DGR Nearing Completion
Sweden’s progress intently mirrors Finland’s, the place the world’s first DGR is nearing completion, spearheaded by Posiva. Development of the Onkalo repository, which started in 2004, has to this point included the event of a 430-meter-deep storage system inside crystalline bedrock, that includes spiral-shaped entry tunnels, vertical shafts, and encapsulation amenities. In a trial run launched in September 2024, Posiva efficiently encapsulated and saved three canisters full of non-radioactive check components.
The trial goals to validate your complete disposal course of, together with encapsulation, transportation, and closing emplacement in bedrock. If all goes in keeping with plan, full-scale disposal operations may very well be prepared to start inside the subsequent two years. In December 2024, nevertheless, Finland’s Radiation and Nuclear Security Authority (STUK) delayed its security evaluation of Posiva’s working license for the above-ground encapsulation plant and closing disposal amenities by a 12 months, citing incomplete supplies and up to date technical plans from Posiva. STUK now expects to ship its security assertion by Dec. 31, 2025.
Finland and Sweden’s tasks, notably, profit from a collaborative strategy. Just like the Forsmark mission, the Onkalo mission will use SKB’s KBS-3 repository technique. In December, SKB introduced an settlement with Posiva to weld the bases of canisters for Finland’s closing repository for spent nuclear gas. The work, scheduled to start in 2025, shall be carried out at SKB’s Canister Laboratory in Oskarshamn, leveraging superior friction stir welding know-how.
—Sonal Patel is a POWER senior editor (@sonalcpatel, @POWERmagazine).
