One giant leap or a very small step?

It was good to see that The Independent had a big piece on fusion power on Saturday ‘One giant leap for mankind: £13bn Iter project makes breakthrough in the quest for nuclear fusion, a solution to climate change and an age of clean, cheap energy’) as fusion hadn’t had much press coverage in the last few years. Once seen as the inevitable future of energy supply, fusion – aka ‘the power of the sun’ – is still seen by many as the holy grail, offering unlimited, clean and cheap power. In fact, the famous quote about nuclear power being ‘too cheap to meter’ (made by Lewis Strauss, Chairman of the US Atomic Energy Commission in 1954 and frequently repeated in the 1950s and 1960s) actually referred to the promise of fusion power rather than any reality of conventional nuclear fission power.

The Independent article was covering the ITER project, a huge and important £13 billion multi-national project to advance fusion research. ITER is the latest in a long line of fusion experiments that create very high temperature plasma and contain it in a toroidal, ‘doughnut’ shaped vessel using magnetic fields to prevent the plasma touching the containment vessel. These vessels are gently called Tokamaks, a term coined in Soviet Russia after they were invented by Igor Tamm and the great Andrei Sakharov, who designed the Soviet thermonuclear bombs and later went on to win the 1975 Nobel Peace Prize after becoming a dissident.

Fusion research, however, has a very long history of being used to feed dreams of unlimited and clean nuclear power. Even if ITER is successful and produces the planned 10 times as much power as it consumes it is a long way from a commercial fusion reactor, if it is ever achieved. ‘First plasma’ (not the same as actual fusion) is planned for 2022 (2 years later than the last plan – and 6 years after the original planned start-up date) and this will be followed by a gradual ramping up of power and ‘going nuclear’ with the injection of tritium in 2027/28 (on the current plan). Even if ITER achieves the 10 times as much power as it consumes goal it will always remain an experimental tool. (By the way this often quoted10 times ratio is mis-leading as it means 10 x as much heat produced as power in – not 10 x as much power out as power in). Even on the optimistic scenario a commercial fusion reactor is unlikely before 2050 and it seems that physicists have been predicting that ‘fusion is 40 years away’ for many years and even decades.

ITER is an incredible project and we do need to carry on with these kinds of experiments, if only to better understand how the universe works, but we also need to be realistic about the prospects for commercial fusion power. Headlines such as ‘ITER makes breakthrough in fusion power’ are very misleading when all that has happened is that construction has started.

The ‘clean’ aspect of nuclear comes for the fact that the fusion reaction combines isotopes of hydrogen (deuterium and tritium, abbreviated to D and T) to produce isotopes of helium which sounds great as hydrogen and helium are fairly innocuous until you remember that the D-T reaction produces a very high neutron flux, i.e. a large flow of high energy neutrons, something like 100 times as high a flux as that produced in a conventional fission reactor. This neutron flux will irradiate whatever materials are used to contain the plasma, making them radioactive. When the JET project, a forerunner of ITER in Culham in Oxfordshire, ran a single series of D-T tests the vacuum vessel was sufficiently irradiated that it required remote handling for a year. The materials problems of fusion reactors are immense. The containment vessel, as well as being irradiated with an extremely high flux of neutrons, has to withstand extremely high thermal loads as the plasma is at very high temperatures (more than 100 million oC no less). Even if the problems of materials can be solved it is impossible to realistically predict the costs of fusion power 40 years from now and it has to be said that the track record of the nuclear industry on cost prediction is abysmal.

I am a technological optimist but on fusion, at least conventional ‘big science’ Tokamak based fusion I am pessimistic. Every now and then reports surface of unconventional fusion developments emerge. In February 2013 It was reported that the Lockheed Skunk works (famous in aerospace circles as the developer of spy planes, the U-2 and the still incredible after fifty years SR-71), is working on a 100 MW, “trailer sized” fusion plant with the first prototype predicted for 2017 and commercial units by 2022 (here). Like a lot of these stories you have to be sceptical but as I have said before, the one certainty is that the future won’t look like the conventional scenarios predict, and I would be less surprised by an ‘out of the box’, completely novel new technology than I would be by the Tokamak approach producing a commercial fusion reactor by 2050. Maybe we will be using fusion power by then.