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Many things remain unknown about Sweden’s nuclear programme, especially why it was suddenly discontinued. It is interesting to note, of course, that the US intelligence community estimated that Sweden was on its way to the weapon up until 1964. Later intelligence assessments are considerably more cautious. That’s probably because our American cousins knew that Sweden wasn’t seeking it any more. I say cousins as about 1 in 20 of the US population is said to have Scandinavian heritage. My favourites of those are probably Uma Thurman, Charles Lindbergh, Kim Basinger and Buzz Aldrin: beautiful women and daredevil pilots.

Cultural similarities aside, little is known about the deal that was made between the Swedish and U.S. governments at that time. Details seem to be heavily classified on both sides of the Atlantic. Swedish historian Wilhelm Agrell, however, points to the mysterious enlargement of Swedish Air Force bases in the latter half of the 1960s, where several runways were extended to be able to receive strategic bombers. Of course, the Swedish Air Force had none of those. This week, I spoke with Ove Bring, a mentor of mine and author of a 2008 book on Swedish Neutrality. He also told me of the Air Force’s decision to equip Swedish tankers with NATO specification nozzles. It would seem like the Air Force started to work closely with its NATO counterparts in the mid 1960s, but few primary sources exist to confirm this.

While it will take some time to get confirmation on why Sweden abandoned its weapons plans, it is possible to piece together the programme itself. Sweden’s fuel cycle activities in the 1950s and 1960s are fairly well documented. When reading about many of these assets, their relationship with the military programme is implied, but never stated and sometimes denied. Most fuel cycle assets except a reprocessing facility were in place in 1969. However, by that time Sweden had joined the 1968 Nuclear Non-Proliferation Treaty, and its weapons experts had become disarmament experts. In the 25 years that followed, most assets were shut down or decommissioned.

This post is based on a number of sources, including some primary documentation, papers written by FOA researchers, as well as, surprisingly, local community history websites. There are a number of good reports written on the programme, but some of them seem speculative or vague in parts. Of course, the writings of Wilhelm Agrell and Thomas Jonter is highly recommended.

Uranium extraction

The designers of Sweden’s nuclear programme realized, as so many other states seeking nuclear weapons, that the key to the bomb is easy access to uranium ore. If you do not have access to domestic ore, its little point engaging on a full-scale weapons programme. In this respect, Sweden found itself in a favourable position. The country was, and still is, very rich in natural uranium. However, the ore grade is quite low (mostly shale), and therefore requires extensive mining and milling. According to a relatively recent survey, Sweden has something between 4 and 32 million tonnes of extractable ore – which was enough for the surveyor to call the country “the Saudi Arabia of uranium” (Continental Precious Minerals Inc., 2005: Results of NI 43-101 Geological Report 7/29/05).

Be that as it may, the ore grade in Sweden varies between 200 and 300 parts per million, which makes it mostly uneconomic to extract. The uranium is hidden in Cambrian period seabed, formed some 400 to 600 million years ago. The Swedish weapons programme focussed on two areas.

Kvarntorp (59° 7’32.11“N 15°16’23.32“E). Uranium extraction started in 1953 by a Swedish government public venture (Svenska Skifferoljebolaget), which had been conducting oil exploration in the region since 1941. The ore in the area is extremely low grade (only 200 parts per million). By 1956, the company had only managed to extract about five metric tonnes of uranium. When mining stopped in 1963, the company had managed to extract about 50 metric tonnes of uranium.

Ranstad (58°16’19.09“N13°42’44.36“E). The government instead decided to go for the mine in Ranstad. AB Atomenergi got permission to excavate the area in 1959. Ranstadsverket was inaugurated in 1965, but was only running for about four years. In 1969 the mine was shut. It had extracted about 200 metric tonnes of uranium. This production is still accounted for in the OECD Red Book.

Norwegian heavy water
(59°52’43.59“N 8°33’27.03“E)

Another asset that the Swedes needed was heavy water to moderate their reactors. US supplied heavy water came with a troublesome string attached – namely the right to inspect the facilities where the water was used. However, neighbouring Norway had no qualms exporting the precious commodity without strings. Under secrecy, Sweden purchased five tonnes of heavy water from its neighbour.

The Wallenberg family might have facilitated the deal. Marcus Wallenberg, a Swedish lawyer and banker, sat on the Norsk Hydro board for 37 years. Norsk Hydro owned and operated the Norwegian heavy water plant in Rjukan. Wallenberg was also a founder of ASEA (which were later in charge of developing Sweden’s nuclear power plants) and the family controlled SAAB, the makers of most fighter-bombers of the Swedish Air Force.

The Swedes also had a good ally in Jens Christian Hauge, the Norwegian defence minister, an eccentric former resistance fighter. The Social Democratic leadership in Sweden despised him. Prime Minister Erlander, for instance, once described him as reckless. But Hauge had a good relationship with the Swedish military, and that relationship is sometimes described as one contributing factor to Sweden’s closeness to NATO. The Swedes had noted that Mr. Hauge had already helped orchestrate an export of safeguards-free heavy water to Israel. If Norway could export to Israel, why would it not export to its good neighbour?

FOA Grindsjoen
(59° 5’8.08“N 17°52’16.51“E)

The Swedish weaponization effort was located in a research area south of Stockholm, called Grindsjoen. The research facility was established in 1941 through a personal donation of Olof Arrhenius, son of the Nobel-prize winner Svante Arrhenius (a Swedish chemist and physicist). It was established to promote ‘natural sciences for defence needs’. It was initially never a formal authority of the state, but rather a collaboration of the physics faculties of all Swedish universities. The military found the location perfect. Since it was so remote, it was easy to keep it secret. The remote location was also appealing to the young scientists employed there. The nature was beautiful, and the local waterways were perfect for fishing and other activities.

At the end of the 1950s, it employed about a hundred scientists and engineers, all tasked to figure out how to build a nuclear weapon. According to some who worked there, they never actually received any instruction to build the weapon. They were conducting basic theoretical studies: such as implosion technology, material studies (especially on UK supplied plutonium), and other basic calculations. The design team early opted for a plutonium-fuelled implosion device. Calculations on the optimum configuration were made on a state-of-the-art IBM 7090 computer installed by FOA in 1961 (the IBM 7090 was also used by NASA in the Mercury Programme). They validated the calculations by conducting cold tests with suitable surrogate materials. The conclusion was that it was not a simple feat to achieve ideal geometry. However, within a couple of years, the team felt that they had good knowledge of what needed to be done.

The Grindsjoen team also needed to know how plutonium behaved under intense pressure. They knew that if they could increase the metal’s density (under pressure), the critical mass would decrease. For that reason alone, high explosive research got priority. The FOA team therefore conducted compression tests where small samples of plutonium were compressed by high explosives within a steel container (which in turn was placed in a facility glove box). The team studied, albeit not very extensively, casting, shearing, and stabilization of plutonium metal. And they also developed a prototype neutron initiator.

The R1 reactor
(59°21’0.33” N18° 4’0.91“E)

The R1 was Sweden’s first reactor. It was fuelled by three metric tonnes of uranium metal provided by France, and moderated by five tonnes of heavy water supplied by Norway. The reactor is located 27 meters under the buildings of the prestigious Royal Institute of Technology. It was not a reactor designed to produce significant quantities of weapons grade plutonium (its effect was only 1 MWth). Rather it was built to give the Swedes reactor operation experience and to supply knowledge for how to build bigger, more powerful, reactors down the line. The CEO of AB Atomenergi, none other that Sigvard Eklund, inaugurated the reactor in 1954. One of the scientists who worked there was Professor Rolf Maximilian Sievert. AB Atomenergi made no secret of the reactor. Indeed, the Swedish King was present at the inauguration, and there were even postcards produced with the reactor as a motif.

The R2 and R2-0 reactor at Studsvik

The second reactor to be built was the R2, a pool type reactor with a 50 MW thermal effect. The R2-0 reactor was much smaller, with a 1 MW thermal effect. Both reactors were commissioned in 1960. The idea was to transform the sleepy little town of Studsvik into a nuclear research area. The institute was initially called “Atomic City”. Both reactors were nominally civilian, and was brought on-line for material testing and irradiation. The reactors were shut down in 2005. Remarkably, the US Atomic Energy Commission contributed 350,000 dollars to its construction. The United States also supplied the reactor with its fuel, 93.5 per cent enriched uranium. A typical core started with a load of 12-13 kilograms of highly enriched uranium, but prolonged burn-up often reduced the quantity to about 160 grams.

The R3 reactor at Agesta

One of the most fascinating reactors associated with Sweden’s efforts to seek nuclear weapons is R3/Adam. This was a small nuclear power plant, which was not really part of the weapons programme. It was seen as a test reactor on a very large scale. It had an 80MWth effect (about 12 MWe). The heavy water was supplied by the United States. The reactors burn-up was declared to be 3000 MWd/t. The total fuel load was 18 metric tonnes of natural uranium. If you simulate the reactor with the IAEA’s INFCIS system, you’ll find that the spent fuel if off-loaded within the year, would have contained nearly 27 kilograms of Plutonium-239 and only about a kilogram of Plutonium-240. In other words, near perfect weapons grade plutonium. Some of this plutonium is still stored in Sweden (not enough for a weapon). The vast majority has been shipped off to the United Kingdom.

The idea was not to use Agesta as the plutonium producer. For that purpose, AB Atomenergi was building a huge heavy water moderated reactor near Marviken. However, as the Marviken project was running into difficulties in 1966 and 1967, the military started to turn its attention to Agesta again. However, the heavy water was supplied from the United States, which meant that there was no easy way to bypass safeguards. Some preliminary plans for a crash program were drawn up. This would involve emptying Agesta of all US supplied heavy water and fill it up with Norwegian supplied stocks. However, these plans never materialized.

Agesta is remarkably well preserved today. According to visitors, one gets the feeling that the operators are out on a coffee break and may return any moment. However, the Swedish Nuclear Inspectorate has given assurances that the reactor itself may not be run without significant investment. At present, there is a battle going on between those who want to keep the reactor as a cultural artifact, and those who want to tear it down.

The R4 reactor at Marviken
(58°33’10.65“N 16°49’55.65“E)

R4/Eva was to be the biggest reactor produced. It was finished in 1968, but never got permission to load. Moderated by 185 metric tonnes of heavy water, the reactor effect was about 100MWe. The reactor was designed to be able to be loaded and unloaded while in operation. This is obviously useful when producing plutonium for weapons, since it allows the reactor operator to control the burn-up without having to shut the unit down. However, the link to the military programme was never made explicit. The reactor was planned to produce about 80 kilograms of weapons grade plutonium per year.

In his recollections, Peter Margen, the AB Atomenergi manager responsible for reactor projects wrote “… our design team at Atomenergi had introduced the requirement that it should be possible to refuel at full reactor pressure, and thereafter even at full load for purely economic reasons, initially as part of the studies of future large scale plants, and then in our suggested design for R4/Eve. In our discussion with Atomenergi management, the fact that this could also be of value if a situation would arise in future where the production of military plutonium became desirable was mentioned, but never as a directive for our design work.”

However, the design had a flaw, which necessitated the use of slightly enriched (1.2 per cent) uranium and a higher burn-up. Initially, the designers envisioned a burn-up of 5,000 MWd/t, but this was later increased to about 13,000 MWd/t. This fuel could only be supplied by UKAEA. Large quantities of heavy water had been promised from Savannah River. The changes needed delayed the project by a year and a half, and would have considerably increased cost. The plans to bring the reactor into operation were abandoned.

Lessons learned from Marviken were later applied in the construction of the O1 light water reactor in Oskarshamn. By then, all nuclear weapons plans had been abandoned completely.

Sannas Reprocessing Plant
(58°44’29.57“N 11°14’50.93“E)

In the late 1950s, money was allocated to buy land near Sannäsfjorden. It was here, as far away from the Baltic Sea as possible, where the government planned to build a reprocessing facility. AB Atomenergi bought the land in 1963, and later expanded the area to 2.3 square kilometres. Advanced studies were made to build the facility underground, straight into the cliffs by the coast.

The project was discontinued in 1970. Formally, it was due to opposition from the local council. However, it seems more likely that Sannäs was abandoned at the same time as the Marviken project collapsed.

Nuclear testing

The Supreme Commander’s Nuclear Weapons Group (Kärnladdningsgruppen) very briefly touched on nuclear testing in a classified 1962 memorandum. They concluded that Sweden had the capacity to carry out underground nuclear tests in their northern and western mountain ranges. Interestingly, however, they also held that nuclear testing, albeit desired, wasn’t necessary for the production of a nuclear device. This to me, at least, indicates high confidence in the design concepts worked out at FOA Grindsjoen as early as the beginning of the 1960s (Fst/Forskn 21/9 1962 nr KH 0800).

The Ahasverus system

Reportedly, the Swedish Air Force considered deployment and basing of their new weapons. According to some sources, about 100 weapons were ordered. Some of these weapons should have been stored in underground storage facilities, and the operational bombs should have been rotated around on active bases. The Air Force called this the “Ahasverus System”, after the lore of the Jew who taunted Jesus on the way to the Crucifixion and was then cursed to walk the earth until the Second Coming.

So what remained to be done?

According to former FOA researchers, Sweden still had some way to go. Amongst other things, it needed:

√ To accumulate a sufficient stockpile of safeguards-free weapons grade plutonium. This would have involved running the reactors for a while before committing to the weapon.

√ To finish the reprocessing facility.

√ To finish work on the weapons design.

√ To build a metallurgical laboratory capable of treating the plutonium, shaping the pit, and assembling the physics package.

If Sweden had not signed up and ratified the NPT, a blue and yellow bomb could have been reality in the first few years of the 1970s. Without doubt, all preparations for the bomb would have been carried out under the guise of its “peaceful nuclear programme” and under the concept of “expanded defensive research”.

Comment [12]

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.

Origins

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.

Controversy

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.

Downfall

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.

Comment [8]