Where to put the deadly waste? In Sweden, power plant operators and the state are confident they have found the answer. After decades of planning, debates, and political wrangling, Climate and Environmental Minister Romina Pourmokhtari (Liberal) appeared radiant at the groundbreaking for one of the first final repositories ever, about a year ago.
Not far from the Forsmark nuclear power plant site, 140 kilometers north of Stockholm, a vast underground tunnel system is now being built. At a depth of 500 meters, Sweden’s radioactive waste will lie until it presumably becomes harmless in roughly 100,000 years. “Historic” the minister called the groundbreaking at the time — and not only for Sweden, but for the rest of the world as well. “We are showing that we have actually developed this method and are now starting to implement it,” she said. Approval had been granted in early 2022 by her Social Democratic predecessor — amid criticism from environmental protection groups.
On April 26, 1986, the worst nuclear disaster occurred in the Ukrainian city of Chornobyl, then part of the Soviet Union (Russian: Chernobyl). A radioactive cloud contaminated large parts of Europe. Forty years later, looks back in a special section and ahead. The generally uses the local-language spelling for Ukrainian places, not the Russian one — as with Chornobyl.
The radioactive waste from the twelve Swedish nuclear power plants to date, totaling 12,000 tons, is to be packed into 6,000 copper capsules and deposited in the tunnel system. The responsible nuclear waste company SKB, owned by the reactor operators, calls the system KBS-3, after the third and final design for the repository plans from 1983. KBS also corresponds to the three barriers of the concept: copper, bentonite, and Swedish bedrock.
A five-centimeter-thick copper layer surrounds the five-meter-long capsules and their steel core. The copper is intended to protect the containers against corrosion. They are stored in the clay mineral mixture bentonite, which is meant to cushion possible tremors in the rock. When — planned for 2090 — the last capsule is deposited there, the repository is to be sealed.
Double Safeguard Against Leaks
The bentonite is supposed to slowly absorb groundwater and fill the voids. Ideally, this mass would, if by any chance a crack were to form in a copper capsule, prevent water from entering the container and prevent radioactive material from escaping into the rock. And should, again by improbable chance, radioactive material manage to penetrate the bentonite layer, the rock itself would hold it back with its micropores. That is the plan.
Doubts existed and exist mainly about the durability of the copper capsules claimed by SKB. Instead of infinite durability, corrosion experts fear a decisive weak point here, with possible leaks after as little as 100 years. Greenpeace had accused the Swedish government, after the construction permit was granted, of being pulled along by the nuclear lobby without regard to consequences.
Construction is proceeding one way or another. And since the liberal-conservative government, with the backing of the right-wing Sweden Democrats, is currently doing everything to usher in a second bloom of Sweden’s nuclear power era, the story is far from over. If new nuclear power plants are added as the state desires and heavily funded, Sweden will need more final repository capacity. The high costs of these facilities make investors hesitate. Therefore, the state plans to participate in future nuclear waste disposal with billions in funding.
