But didn’t finish the job.
Relax. There is no Swedish nuclear bomb.
But there almost was one. If this blows your mind, good. It should.
For more than two decades after World War II, Sweden seriously explored becoming a nuclear weapons state.
Today Sweden is often associated with diplomacy, neutrality, and international disarmament efforts. Our peace negotiators often play key roles in conflict resolution around the world. Yet during the Cold War, Swedish military planners and politicians quietly investigated whether the country should build its own atomic bomb. It wasn’t just plans.
The idea emerged after Hiroshima and Nagasaki.
When the Second World War ended in 1945, the atomic bomb changed the rules of international politics. The Soviet Union was growing stronger, Europe was divided, and Sweden found itself in an uncomfortable position: officially neutral but located between the two emerging power blocs. Smack in the middle.
The argument for a Swedish bomb was simple: if another country could threaten Sweden with nuclear weapons, then the only protection was to possess nuclear weapons of its own.
In 1945 the government instructed scientists and military researchers to study the new technology. The work eventually became the responsibility of the Swedish Defence Research Agency, FOA. Over the following years Sweden examined everything required for a domestic nuclear weapons program: uranium mining, nuclear reactors, plutonium production, bomb design, and delivery systems.
The ambition was not to build a strategic arsenal capable of striking Moscow or Washington. Swedish planners were mainly interested in smaller tactical nuclear weapons that could be used to defend Swedish territory in the event of a Soviet invasion.
Research expanded throughout the 1950s.
Sweden possessed uranium deposits, developed nuclear expertise, and invested heavily in nuclear technology. Military planners discussed how atomic weapons could fit into the country’s defence doctrine.
Intelligence agencies abroad noticed the progress. By the late 1950s, foreign observers believed Sweden had the technical capacity to become a nuclear power within a few years.
Testing
Large conventional explosions were carried out near what is today the Vidsel test range in Norrbotten in the north of Sweden. The purpose was to study the effects of powerful blasts and gather data relevant to nuclear weapons research. One of the explosions was so large that it left a crater that later filled with water and became a small lake.
Yet despite the technical progress, political support gradually weakened.
The program was expensive. Public opposition to nuclear weapons grew during the 1960s. At the same time, Sweden became increasingly active in international efforts to prevent the spread of nuclear weapons.
Another factor was security.
Although Sweden was officially neutral, historians have argued that informal security ties with the United States reduced the perceived need for an independent nuclear deterrent.
In 1968 Sweden signed the Nuclear Non-Proliferation Treaty, committing itself not to acquire nuclear weapons. The weapons program was subsequently dismantled and formally ended in 1972.
Sweden came remarkably close to becoming the world’s next nuclear weapons state. It had the scientists, the industrial capacity, the uranium, and much of the required infrastructure.
What it ultimately lacked was the political decision to take the final step. Today on June 6, Sweden’s national day in 2026, the thought of Sweden developing an atomic bomb seems like science fiction. But during the Cold War these plans made sense to the Swedish politicians and military planners. For a time, one of the world’s most peaceful countries came very close to building a nuclear bomb.