May 13, 2008
Fusion 2.0
Over at Cosmos, Robin McKie looks at the International Thermonuclear Experimental Reactor:
Recreating the fusion process clearly offers great rewards, but it is not an easy task – to say the least. In particular, the business of containing a cloud of plasma that has been heated to around 100 million degrees Celsius has taxed the imaginations of a great many scientists. You can’t hold super-hot matter in an old bathtub, after all. In the end, it took the ingenuity of Russian scientists Igor Tamm and Andrei Sakharov, working at Moscow’s Kurchatov Institute in the late 1950s, to come up with the answer: the tokamak.
The key feature of a tokamak is its central chamber which is shaped like a giant, hollow doughnut or torus, and which gives the device its name. Abbreviating the Russian ‘TOroidalnaya KAmera v MAgnitnykh Katushkakh’ results in ‘tokamak’, or its similar English equivalent, TOroidal CHAmber in MAgnetic Coils (tochamac). Powerful electric currents are passed through coils that wind round the doughnut-shaped chamber and through the plasma inside it, creating a twisting magnetic field that holds the super-hot plasma in a tight, invisible grip.
However, massive amounts of electricity are needed to create this unseen container, and to date, far more energy has been spent powering-up tokamaks than has been released through the resulting fusion of atoms. For example, JET soaks up 25 megawatts of electrical power to generate only 16 megawatts of fusion power. However, ITER – which will be the biggest tokamak reactor ever built when completed – is scheduled to have an output of 500 megawatts for an input of only 50 megawatts of electricity.
Posted by Robin Varghese at 09:15 PM | Permalink
Comments
Given the Peak Oil crisis that is now really upon us, I hope Iter will be fast-tracked and given the priority it needs.
Posted by: Jared | May 14, 2008 2:23:55 PM
And other approaches to fusion?
Fascinating article and it's nice to renew the feeling of optimism that has characterized the fusion program for so long. I do hope it works if for no other reason than to act as a step towards what will ultimately be the most widespread source of non-solar derived energy on the planet, doing for energy what micro-processing technology and the silicon- chip did for computational memory and availability; making it, at long last, almost too cheap to meter and essentially ubiquitous; in short, the Star Trek future.
However, I would have appreciated hearing a little bit about the burgeoning research in Inertial Electrodynamic Confinement (IEC) fusion which has emerged over the last few years, the research in which is being carried out now at many locations both academic and private research. The issues of containment of hot plasma seem to be bringing into question the meaning of "hot" when describing velocities that approach the speed of light, which some think IEC fusion may be effective at addressing whereas the large Tokomaks will not.
One researcher, the late Dr Robert Bussard, speculated that the reason the old USSR researchers "gave" the West the key elements of their Tokomak research was not to further the research but to permanently hobble the West's research into more attainable forms of fusion, which up until that time had been through the work of Philo T. Farnsworth's and Robert Hisch's "fusors" using high speed electron guns and magnetic grids with what would be by today's standards, a still rudimentary understanding of the problems they were encountering. That understanding has advanced considereably in the last couple of decades.
Even the rosiest estimates to break even with the Tokomak still leave a lot to be desired before the Tokomak can ever be made as integratable as even a modern day large scale electrical generator, and if they become the new standard they will initially require a huge outlay in expense and time for the existing power grid to configure its considerable scale into our infrastructure. The IEC's approach forsees smaller and more ubiquitous, and non-radioactive, processes. It is worth googling-up up the term Polywell Fusion for those interested. You'll find a number of interesting sources for further exploration.
Posted by: doug l | May 14, 2008 2:32:36 PM
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