Andreas PersboThe Blue and Yellow Bomb (Part 1)

Jeffrey and I have something in common. I’m Swedish. In his youth, Jeffrey went to some Swedish school (Augustana College in Rock Island, Illinois). And we’ve both developed an interest in nuclear weapons issues.

But what do Madonna and nuclear weapons have in common? Nothing except that Nothing Really Matters was shot on the site of the R1 reactor in Stockholm, Sweden.

This reactor, buried about 30 meters under the city, played a small but important role in Sweden’s nuclear weapons programme. The programme is an interesting piece of non-proliferation and disarmament history, of which relatively little is known, at least outside Sweden.

This post is very long, so I’ve divided it into two parts. The first will go through some of the political context. Later, I will post on some of the fuel cycle facilities that have been identified.

I’ve drawn on the writings of Wilhelm Agrell and journalist Christer Larsson. The former has written a book on the subject in 2002, and the latter is the author of the 1985 article in Ny Teknik that first attempted to chronicle what really happened during the 1950s and 1960s.

A majority of the post is directly sourced from Peter Hansson’s excellent documentary on Swedish National Radio, which was broadcast in 2008. I’ve also had some brief conversations with people both in Sweden and Norway on the topic. Norway’s role, in particular, is spellbinding. Sweden’s western neighbour was the first non-nuclear weapon state to acquire a nuclear reactor. And it also had large quantities of another important asset: safeguards free heavy water.

Some of the secret documentation on Sweden’s nuclear programme was declassified in the mid-1990s. But the qualified secret material, which is under a 70 year classification rule, is not likely to be released until the beginning of the 2020s. Moreover, some believe that the really important documentation was never archived – it may not even be written down. This, of course, fits nicely with a well-known exception to the Swedish constitutional principle of government transparency. Certain memoranda, written simply as a support for your memory, are considered private and may not be given out to the public. We used this loophole frequently at the Swedish Court I once worked in, in order to protect internal assessments and investigations into sensitive cases.

The Swedish nuclear weapons programme was also heavily sectored. No person had access to the complete picture. This has resulted in an increasingly fragmented recollection of what actually happened. Some argue that a nuclear weapons programme never can develop secretly in a free and open society. Yet, the true extent of democratic Sweden’s programme is still unknown. And I suspect its true nature will remain opaque for many more years to come.


The Swedish military reacted slowly to the news of Hiroshima and Nagasaki. Few military strategists within the military high command saw the atom bomb as a truly revolutionary weapon. Instead, they saw it as a powerful asset to be used only sparingly and at very important targets. Gradually, however, the military started to realize that the atomic bomb was a true game-changer. As tension between the Soviet Union and the United States rose, the military started to believe that the next war would be fought with nuclear weapons, and felt that Sweden needed to prepare itself for that. British and U.S. ideas heavily influenced the Swedish Defence Forces’ doctrinal thinking at that time. And some may recall that influential strategists, such as Air Marshall Sir Arthur Harris, advocated the use of nuclear weapons to deliver a decisive and pre-emptive blow to the perceived Soviet threat. This must have resonated strongly within the Swedish High Command.

The Air Force, under the direction of General Nils Per Robert Swedlund, was one of the driving forces behind the nuclear weapons programme. It realized that Sweden was in a favourable position. The country’s industry was untouched by the Second World War, it had excellent scientific expertise, and the country was well connected. Amongst the people that the country reportedly depended on for support was Nils Bohr, a world-leading physicist based in Demark, and of course Glenn Seaborg, an American 1951 Nobel-prize winner, generally considered to be the father of the U.S. plutonium production programme. Dr. Seaborg’s parents were Swedish, and he himself spoke the language fluently. After the end of the programme, Seaborg was elected a foreign member of the Royal Swedish Academy of Sciences in 1972. It is sometimes said that Seaborg played a role in dissuading the Swedish government from seeking weapons, but the exact details of what happened in the first half of the 1960s are still classified.

One interesting aspect of the Swedish programme is its close relationship to private enterprise. In many other aspiring states, the weapons programme has been an exclusively state run effort. In Sweden, however, private industry was deeply involved. In fact, the programme started with the founding of a joint government-business venture. In 1947, the government established AB Atomenergi (the Atomic Energy Company). The company was owned by 4/7 by the Government. The other 3/7 was owned by a number of private companies active in the mining, steel and manufacturing industries. The company’s task was to establish the fuel cycle assets necessary for the weapons programme. The military would work out the bomb design. Therefore, AB Atomenergi had a close relationship with the Defence Research Institute (FOA) from the start, through a co-operation agreement signed in 1948. The Defence Research institute had already established a research area south of Stockholm (FOA Grindsjoen) that became the epicentre for military R&D (more on this area in the next post).

As in other proliferative states, the public was never informed about what the reactors were built for. The nuclear programme was portrayed as civilian. Atomic power was seen as the key to a new and better type of society, where all energy needs will be easily satisfied. The establishment of fuel cycle assets were seen as indicators of Swedish industrial progress, and was, I believe, a source of national pride.

In the meanwhile, the military made no secret that they were working on nuclear weapons related questions, but argued that all research was defensive. In 1954, Prime Minister Tage Erlander delivered a speech that argued that the atomic bomb had put all nations in a ‘state of fear’, and held that in order to protect itself from its effects, one would need to know how the weapon worked. This was spinned as a common-sense justification for the research throughout the 1950s, and would take absurd proportions with the concept of ‘expanded defensive research’, introduced in 1959.

He’s working for the Atomic Energy Company

Private enterprise

Sweden, despite having a reputation of being a socialist country, has always had a very strong business culture. The nuclear programme was no exception. Fuel cycle research was conducted under the umbrella of AB Atomenergi, but other interests were pushing for the bomb. The power company ASEA wanted the weapon, since that meant that it would get more orders for nuclear power plants (ASEA later became ASEA-Atom and is now part of Westinghouse). Moreover, the powerful arms manufacturer Bofors reportedly made several internal studies on its capability to assemble the weapon, and later lobbied government to get that role (Bofors is now part of BAE).

Of course, aircraft manufacturer SAAB would also have been involved in the effort. Although the design team at FOA Grindsjoen had some early design ideas about missile delivery, the Air Force strongly advocated the concept of using the SAAB 32 Lansen aircraft for weapons delivery. Studies, although ‘not terribly detailed’, were made on how the weapon would need to be designed to be hung under the fuselage of the platform.


The Air Force remained the key driver behind the programme. After all, it was the Air Force’s fighter-bombers that were supposed to deliver the new weapon to target. But the programme had no public face. The various agencies and companies that worked on the programme realized that they could do a lot of progress without involving the Parliament or the general public. It was only after a fall-out between the Defence Minister (Sven Andersson) and the Supreme Commander of the Swedish Armed Forces (Swedlund) that the research became public. Surprisingly, the Defence Research Institute (FOA) made a public request for funds to develop nuclear weapons. A divisive and bitter debate ensued, which almost threatened to break the ruling Social Democratic Party apart.

Enter Olof Palme. This young man, which later was to become one of Sweden’s best-known Prime Ministers, was called in by Prime Minister Erlander to unify the party and give some top cover for the weapons effort. Palme was the secretary in a Social Democratic Party working-group on the nuclear weapons question. The group released its report in 1959, and the official position became ‘we’re not seeking it’ but unofficially the government wanted ‘freedom of action’. The FOA request was denied, but the budget on defensive research was significantly increased. Prime Minister Erlander, in consultations with the Supreme Commander, reportedly made it clear that ‘defensive research’ also included work on the weapon itself. The term used was ‘utvidgad skyddsforskning’ (i.e. expanded defensive research). In fact, the defensive programme remained a systematic offensive programme.


From 1962 and onwards, the programme slows down. There were likely many factors in play. Public opinion turned sharply against nuclear weapons, and the Swedish government played an important role in the negotiation of the 1968 Nuclear Non-Proliferation Treaty. In 1966, Karl Frithiofsson, a Ministry of Defence official, holds a speech at the Royal Defence Collage where the concept of a nuclear armed Sweden was formally dismissed. According to some, few in the audience had any idea what Frithioffson was talking about . However, historians hold that Sweden reached an understanding with the United States at some point during this period. The deal was that the US nuclear umbrella would protect Sweden, and so there was no need for any nuclear arms. Documents from this time are not likely to be released until the 2030s.

Sweden made good use of their expertise after this. Her nuclear weapons experts become ‘disarmament experts’, and made significant contributions to the debate in Geneva and Vienna. And one of the programme’s first directors and driving forces, Dr. Sigvard Eklund, went to Vienna to head up the International Atomic Energy Agency, a post he held for 20 years.

And so, in the years that followed, the programme, and its significant fuel cycle assets, would simply fade from the collective Swedish memory. As the veterans from the programme now quite old, some fear that the true depth of the programme will never be uncovered. In the meanwhile, Sweden’s programme emphasises how easy it is to hide a weapons effort under the guise of a civilian project. It also shows how simple it is to obfuscate a country’s intentions in the name of ‘defensive military research’.

I’m off to India this week. But when I return, I’ll post a list of some of the facilities associated with the programme. I’ll include a description of the well preserved R3/Adam reactor. And, of course, details of R4/Eva, the finished HWR that was never fuelled.


  1. Scott Monje (History)

    Have you tried to find any documentation from U.S. archives regarding the promise to extend the nuclear umbrella to Sweden?

  2. Andreas Persbo

    I haven’t made a serious attempt to do this. I’ve visited the Cold War Archive, but the NIE from that year is heavily redacted.

  3. VS (History)

    A good research topic could be on the similarities and differences of the Swedish and the Swiss nuclear weapons programs, especially on the concept of the atomic bomb as “guarantor of neutrality”. Probably there is something published on it that I’m not aware of. And if my memory serves me right, these two programs also were developed and abandoned roughly in the same decades, or maybe the Swiss was a bit older.

  4. Yale Simkin (History)

    A real nice history of the Swiss program can be found on Carey Sublette’s most excellent site here.

  5. François Heisbourg (History)

    There’s an interesting piece in English on the NIE by Nils Bruselius in “Unilaterally if necessary- one motive behind the american security guarantee to Sweden”, Särtryck ur Tidskrift i Sjöväsendet, issue 1, 2008.

  6. Andreas Persbo

    Thank you François. The article is available here:

  7. mark hibbs

    Andreas, I didn’t know that Eklund was in the program. That would perhaps explain the background of a lot of the decisions he took and positions he defended while at the IAEA. David Fischer, who was head of what became EXPO then, told me many years ago that “Eklund didn’t believe in safeguards.” Eklund was a very complex personality, and the subject deserves a book because a lot of the things he did and presided over became part of “safeguards culture” for decades and also encouraged an esprit de corps which was for many years incredibly strong, had its strengths, but also, in my view, damaged the agency’s credibility at times.

  8. Andreas Persbo

    Mark, Eklund was the CEO of AB Atomenergi. I have audio of him inaugurating the R1 reactor underneath KTH.