The project, which was named the International Tokamak Reactor or INTOR, began in 1979. Each of the four participants – Euratom, Japan, the Soviet Union and the United States – nominated four researchers who would meet in Vienna several times a year for workshops that lasted between four and six weeks. When the researchers returned home they would delegate work to their colleagues to be carried out before the next workshop and so the network of researchers involved became very broad.
The majority of fusion researchers didn’t take INTOR too seriously; they were too busy getting TFTR, JET, T-15 and JT-60 up and running. The regular trips that a few of them took to Vienna were just a sideshow, but the INTOR workshops did gradually build up a database of knowledge on how fusion reactors work, taking results from all the fusion programmes. The workshops produced a number of reports describing the theoretical reactor they were working towards, each report increasing in detail and sophistication. But perhaps INTOR’s main achievement was that it showed the very different traditions and methods of the various fusion research programmes could work together and get things done.
But by the mid 1980s it was clear that INTOR wasn’t going anywhere. Although its designs for an engineering reactor were highly praised by researchers, there just wasn’t any political support for an international project to build a giant fusion reactor. Velikhov was frustrated that his ambition to move quickly towards fusion power generation had stalled. The Soviet Union was certainly in no position at that time to build an engineering reactor itself: the economy was in bad shape and work on the T-15 reactor had all but come to a standstill. Velikhov needed a way to get political support behind INTOR and, by an incredible stroke of luck, an opportunity fell in his lap to take his appeal right to the top. That opportunity came in the shape of Mikhail Gorbachev, an old university friend of Velikhov’s, who in March 1985 became general secretary of the Community Party of the Soviet Union – Russia’s de facto leader.
The two had been at Moscow State University at the same time, Velikhov studying physics and Gorbachev law. Gorbachev became active in the Communist Party and on leaving university rose swiftly through its ranks. In the early 1980s, the deaths in fairly rapid succession of Soviet leaders Leonid Brezhnev, Yuri Andropov and Konstantin Chernenko led the Politburo to decide that younger leadership was needed. So, just three hours after Chernenko’s death, the Politburo elected its youngest member – Gorbachev, aged 54 – to the top job. He immediately made his mark as a reformer with his policies of glasnost (openness) and perestroika (restructuring) which sought to loosen the shackles of the old regime. In foreign policy he made decisive moves to reduce East-West tension. He withdrew SS-20 intermediate-range nuclear missiles from central Europe less than a month after taking office and within six months proposed that the Soviet Union and US both cut their nuclear arsenals by half.
As head of the country’s fusion programme and an old friend, Velikhov met with Gorbachev and described to him how an international project to build a fusion reactor along the lines of INTOR, with Soviet and American researchers working side-by-side, could help to diffuse Cold War antagonism. Gorbachev eagerly adopted the idea and in his first foreign trip, to France in October, he discussed the idea with President François Mitterand and received a positive response. Gorbachev’s next foray abroad was to meet US president Ronald Reagan in Geneva at their first summit. In the weeks running up to this November meeting Velikhov worked feverishly with contacts in the White House to get something ready for the leaders to agree on, despite strenuous opposition from the Pentagon which was concerned about valuable software and technology being handed over to the Soviet Union. The often tense and argumentative summit meeting was dominated by discussions of human rights and the Strategic Defense Initiative, Reagan’s proposed nuclear missile shield. No breakthroughs were made in East-West relations but the two leaders did establish a relationship that would stand them in good stead in the future. The rather bland final communiqué did however include – as one of its twelve bullet points – a commitment by the two powers to work together and with others to establish the feasibility of fusion energy ‘for the benefit of all mankind.’
Ronald Reagan and Mikhail Gorbachev at the Geneva summit, November 1985.
(Courtesy of ITER Organisation)
The government agencies responsible for fusion in each country were slow to get moving in forming a collaboration. It was only after the Reykjavik summit between Reagan and Gorbachev in October 1986, when the matter was brought up again, that the bureaucrats got moving. The United States and Soviet Union, together with Euratom and Japan, formed a Quadripartite Initiative Committee to discuss the idea but talks went far from smoothly. Euratom was already well advanced in planning its follow-up to JET, the Next European Torus, and Japan had its own plans too, so neither of these saw the urgent need for another reactor design. US defence officials were still concerned about the transfer of sensitive technology and the Russians wanted any joint design work to be done in a neutral country. After somewhat tortuous negotiations the four partners agreed to work together for a couple of years to produce only a conceptual design – a broad outline that doesn’t get into the detail needed for actual construction. Paulo Fasella, Europe’s representative at the negotiations, gave the project a name: the International Thermonuclear Experimental Reactor, or ITER. Fasella, a highly educated man who had a glittering career in biomedicine before joining the European bureaucracy in Brussels, pointed out that iter in Latin means ‘the way.’
The headquarters for the conceptual design work was Garching in Germany and the project proceeded in a similar vein to INTOR: each partner seconded around ten researchers to the project who would spend several months each year in Garching and then delegate work to their colleagues back home. The collaboration of researchers from four different traditions didn’t always go smoothly. One American researcher described it like this: the Europeans would rant and rave passionately about every issue and the Americans had to explain to the Japanese that they didn’t really mean it; the Japanese would explain their point of view very calmly and quietly and the Americans had to explain to the Europeans that they did really mean it. There were scientific differences too. The Japanese were keen to have a reactor that could demonstrate continuous, or steady-state, operation, while the Europeans wanted the highest possible gain.
In spite of the differences, this project had a different feel to it than INTOR. Because the scientists were now working as directed by their political leaders it somehow felt more real, as if this reactor would actually get built. That dose of realism was also reflected in the design of the machine. When predictions are uncertain, fusion reactor designers tend towards bigger and more powerful machines in the hope that more plasma and stronger fields will swamp any inadequacies. So while INTOR had predicted that a tokamak 12.4m across with a plasma current of 8 MA would be enough to reach ignition, the ITER conceptual design called for 16.3m and 22 MA.
After two years of work the ITER team had come up with a conceptual design that they could all more or less agree on. The question then was, what to do next? The original plan had been to move straight on to drawing up an engineering design – an exact set of plans ready for construction. But the world had changed since ITER had been dreamt up as a way of alleviating Cold War tensions. The Iron Curtain was falling apart and even the Soviet Union itself would soon cease to exist. ITER’s political raison d’être had evaporated and neither was there an economic need for it: energy was not high on the political agenda in the early 1990s. The project’s momentum carried it forward, but it took the four partners two years to decide on how to proceed. A major sticking point was where the design team would be situated. The dying Soviet state and then the new Russian Federation were in such dire economic circumstances that they could make little real contribution to the project apart from scientific brainpower, but none of the other three partners were ready to concede the design team to the other two. They came up with the unwieldy compromise of sp
litting the team in three: one part in Garching would be responsible for the plasma vessel and everything inside it; another group in Naka would take on everything outside the plasma vessel – including superconducting magnets, power supplies and buildings – and the final group in San Diego would be in charge of overall integration, physics and safety.
By 1992 the engineering design project was ready to go. The teams were given six years to develop the final design. All that was still needed was an overall project leader. There were few people in the world who had the right mix of experience in engineering, plasma physics and the management of large projects. But there was one obvious choice, the person who had for nearly two decades led the design and construction of JET and guided it through the demonstration of H-mode to the first D-T burning in 1991: Paul Henri Rebut. And so Rebut left his beloved JET and moved to San Diego to take the reins of the ITER megaproject.
The designers of ITER were faced with something of a dilemma. This reactor was meant to be a demonstration of technical feasibility but the previous stage in the three-step progress towards fusion power – scientific feasibility – had not quite been achieved. TFTR only reached a gain of 0.3 in 1993 and JET would get to 0.7 in 1997. Only JT-60 managed a gain greater than 1, but that was equivalent gain – what it would have been if tritium had been used. As a result, ITER was saddled with the twin goals of demonstrating scientific feasibility and testing the technologies needed for a power reactor. The problem was that these two goals are not easily fulfilled by a single reactor design.
For an engineering reactor you want a plasma that is stable and quiescent, that will burn for long periods at high gain – mimicking how a working reactor would behave. Such a plasma would be a tool for engineers to test things such as the best lining for the reactor vessel, known as the first wall, so that it will not pollute the plasma and will stand up to years of neutron bombardment. Engineers would also want superconducting magnets because they would reduce the energy demands of a power-producing reactor. They would also want to test blanket modules – sections of the vessel wall – containing lithium which would be converted into tritium fuel by the bombardment of neutrons from the fusion reactions.
But if you haven’t yet achieved gain greater than one, you would ideally want a very different reactor – something that is more like an experimental apparatus than an industrial prototype. You wouldn’t want a reactor with a fixed configuration because you need to try out all possible permutations to get the highest gain. You wouldn’t necessarily want a quiescent plasma; you would want to be able to push it to the edge of stability in pursuit of the best performance. And you certainly would not want complications such as superconducting magnets and tritium breeding blankets that make it harder to interpret results. So, ITER was destined to end up as something of a compromise.
When Rebut arrived in San Diego to take control of the project, he hit the ground running and immediately began remodelling ITER in the image of JET. This is not entirely surprising since JET was the largest tokamak around and had proved very successful. Rebut’s team drew up a design with a D-shaped plasma, similar to JET’s, and with a divertor around the bottom of the vessel, just like the one that at that time was being fitted to JET. The only fundamental difference was the superconducting magnets. Under Rebut’s leadership the already large conceptual design grew even bigger, to a machine nearly 22m across. He increased the number of superconducting magnets to hold this huge volume of plasma in place. The whole magnet system – twenty toroidal magnets and nine poloidal magnets – would weigh a total of 25,000 tonnes, roughly the same as the Statue of Liberty.
Rebut didn’t want ITER to use superconductors. It was possible to achieve high gain with conventional copper magnets but the partners wanted technology that was ‘reactor-relevant.’ Rebut argued that superconductors just made everything more complicated. Superconducting magnets are much harder to make than copper ones and they must be enclosed in a secure container called a cryostat so that they can be surrounded in liquid helium to keep them chilled to close to absolute zero (around -270°C). Because ITER will be producing large quantities of heat from its fusion reactions, the magnets must be shielded or they will warm up and stop operating. So the inside surface of the vacuum vessel would be lined with replaceable steel panels cooled by water flowing inside them.
ITER’s divertor was another key piece of technology because it was the only solid object in direct contact with the plasma during normal operation. Its roles, extracting the exhaust gas from fusion (helium) and absorbing heat, required a material with a high melting point that is able to withstand prolonged particle bombardment. ITER researchers made use of many tokamaks with divertors around the world in their search for the right material. Rebut considered some quite radical solutions to ITER’s many engineering challenges, such as using highly reactive and flammable liquid lithium as a coolant for some reactor components, on top of its role as material to breed tritium for fuel.
The first six months in charge was a gruelling time for Rebut. Every weekend he would fly one-third of the way around the world to the next worksite, spend a week there, then move on again. Despite this itinerant lifestyle he found it difficult to keep up the communication between the three sites. It was a very different operation from JET where he had his whole team around him. Though a brilliant engineer, Rebut was not a natural manager; he found it hard to delegate and so took on much of the design work himself. The international partners didn’t like his style of leadership. They wanted their own researchers, in Naka and in Garching, to play a greater role in the design. ITER was too big a project for it to become a Rebut one-man-show and in San Diego he didn’t have Palumbo and Wüster to shield him from the politicians. The ITER partners wanted a more collaborative approach so after just two years in charge Rebut was eased out.
It was no easier finding a suitably qualified leader than it had been two years earlier, but the person the partners decided upon was not just another European but also another Frenchman. Robert Aymar had led the building of France’s Tore Supra, the follow-on to its Tokamak de Fontenay aux Roses (TFR). But when they asked Aymar if he would lead the ITER project, he said no.
A contemporary of Rebut, Aymar had spent most of his career working at France’s Commissariat d’Énergie Atomique (CEA) on plasma physics. He was inspired by attending the 1958 Geneva conference to pursue fusion because of its possible value to society. By the late 1970s he was in charge of France’s fusion programme and when researchers had done as much as they could with TFR he set out to build Tore Supra. This reactor would be the first large tokamak to use superconducting magnets. With the strong steady magnetic fields they produced, Tore Supra would be able to hold its superheated plasma for minutes at a time instead of the seconds possible in a conventional tokamak.
Aymar realised that for such an ambitious project to be successful he needed to have all of the team together in one place, not scattered around universities and labs across France. Just as was happening at JET across the channel, he needed a team dedicated to this one goal and nothing else. During 1984 and ’85 he persuaded some 300 families to move down to Provence as Tore Supra took shape at a CEA lab complex in Cadarache. Aymar and his team completed Tore Supra in 1988 and in the process created a powerhouse of fusion research at Cadarache. Recognising that success, the CEA offered him the job of heading its whole basic physics division. Aymar was in his element: with a staff of 3,000 scientists he was now responsible for the commission’s work in many areas beyond plasma physics, including nuclear and particle physics. But then ITER came calling.
At that time, in 1994, the pinnacle of fusion achievement was TFTR’s D-T shots with a gain of around 0.3 – hardly a convincing demonstration of fusion. In a few years’ time JET would get closer to break-even but to Aymar’s eyes fusion research had a way to go before it could confidently demonstrate high gain. That being the case, the machine that Rebut had been designing in San Diego was the wrong sort of machine. It was too
much like an engineering reactor and didn’t have the flexibility that may prove necessary to achieve the physics goal of high gain.
Despite his earlier refusal, ITER’s backers contacted Aymar again and asked him to reconsider. Aymar thought hard about it. Although he was enjoying himself running the wide array of fundamental physics at the CEA and was concerned about the current ITER design, perhaps it was his mission in life to guide fusion a bit further along the road to real power generation. He accepted the job, but he wasn’t happy about it. As soon as he was on board he set off to visit the three ITER work sites – Naka, Garching and San Diego. His aim was to steady nerves and build confidence among the researchers after the change in leadership.
But holding together an unwieldy design project would soon prove to be the least of Aymar’s problems as, in autumn that year, the Republican Party took control of both houses of the US Congress. Two months after the Congressional elections, in January 1995, in a conference centre just outside a wintry Washington, DC, Anne Davies, then head of the Department of Energy’s fusion programme, told the directors of America’s fusion laboratories to begin preparing for the worst.
At that time, DoE was spending $350 million per year on magnetic fusion, but once construction began on ITER and Princeton’s proposed Tokamak Physics Experiment (TPX) much more money would be needed. Building ITER alone would consume more than the whole of the current budget. America’s fusion leaders didn’t have to wait long for the axe to fall. Later in the year, when Congress set the 1996 budget, it awarded magnetic fusion just $244 million. This was barely enough to keep America’s domestic fusion programme going, let alone pay for an expensive new reactor to be built somewhere overseas.
Piece of the Sun : The Quest for Fusion Energy (9781468310412) Page 23