"The discovery of nuclear reactions need not bring about the destruction of mankind any more than the discovery of matches" –Albert Einstein, 1879-1955.
In one of my recent postings I mentioned fusion power as one of the huge technological advances waiting in the wings, and I realized I hadn’t heard much about it recently. I soon discovered that I could date the cessation of information back to the late 1980s, when there was a flurry of interest in a scientific concept called “cold fusion.”
Two scientists claimed they had extracted more energy from a room-temperature experiment than they put into it. The discovery was touted as the Holy Grail, the Lost Ark, and the Jewel of the Nile all wrapped in one enormous breakthrough. The problem was that nobody could replicate the effect, although they kept trying, and are trying still. It gave fusion proper – “hot” fusion, if you will – a bad name as well, and I haven’t seen much mention of it in the popular media since then – and that was over two decades ago.
Well, in the mean time scientists have pretty much put all their fusion eggs into one basket, and it is a really big basket. They’re building a huge “tokamak” (the word is a Russian acronym for words that mean “toroidal chamber with axial magnetic field”) – or what might be described as an atomic oven – in the Provence region of France.
Our existing nuclear power plants are all “fission” plants. Very big atoms like uranium and plutonium can be broken apart into pieces: different atoms that are still pretty big. The resulting atoms, combined, weigh just a little bit less than the big atom you started with, and that little bit of extra “stuff” gets turned into energy.
When you have a whole bunch of big atoms breaking apart at once, you have an atomic bomb. When the big atoms are diluted or separated so that they don’t explode, just a few of them break apart, or “fizz,” every second. The energy that’s created is primarily heat, which can be used to run a boiler and thus a power plant.
The problem with fission is that both the atoms you start with and many of the ones that are produced are radioactive. Some of them remain dangerous for millennia. We are accumulating a lot of spent fuel rods and we have to find a place to store them indefinitely, thanks to fission power.
Fusion, by contrast, is pushing together, not breaking apart. It turns out that four hydrogen atoms, the smallest and most abundant atoms in the universe, weigh quite a bit more than one helium atom, and if you can cram those hydrogen atoms together you get helium and a lot of energy.
The radioactive products of fusion are minimal, short-lived, and easily shielded.
Cramming atoms of hydrogen, more precisely of its isotopes deuterium and tritium, together requires lots of pressure, and the resulting nuclear reaction creates a lot of heat. It takes a lot of energy to create and contain the pressure, and the goal of this huge tokamak project is to get at least ten times that much energy out of the reactor in the form of electricity.
Previous attempts haven’t even broken the one-to-one ratio.
The big tokamak will be built by a consortium of the United States, Russia, the European Union, Japan, China, South Korea, and India. That represents half the world’s population. The project is called the International Thermonuclear Experimental Reactor, or “ITER.” “Iter” is a Latin word meaning “way” or “road.” I guess if they had done it in China it would be called the “TAO.”
But there’s a recession, and although all of the partners have made commitments to the building of the enormous structure, budget-trimmers in all those governments are looking for programs to kill or mutilate. From what I can determine, ITER’s funding commitments are intact, but it has no wiggle room for cost overruns and design changes.
Maybe this is the best way to fund the really big research projects. When times get bad, individual nations are likely to put the brakes on projects they fund for themselves. (I could mention the Superconducting Super Collider and Yucca Mountain.) But an international consortium is like a treaty, and it’s hard to renege on committed funding in such a situation.
Anyway, this project is going to be around for a while. It was actually Mikhail Gorbachev’s idea, back when there was a Soviet Union, in 1985. It was 20 years before the site was chosen. The official agreement was signed in November, 2006, and since then the dirt-work has been completed. That may not sound like much, but the raised area where the project’s buildings will be constructed measures about one kilometer by 400 meters, and about 2.5 million cubic meters of dirt were moved to build it. (This is in France, so of course everything is in metric numbers.)
Experiments won’t begin in the tokamak until 2019. It will be a structure of 5½ stories underground and 19 stories above ground. I’ve included an artist’s conception of the machine from the official website (http://www.iter.org/). Look for the tiny man standing on the bottom right to get an idea of the size.
Much of this huge machine will be composed of coils of copper wire to create and control magnetic fields to contain the doughnut-shaped core where hydrogen atoms will be injected under extreme pressure. These coils will be cooled to close to absolute zero, so there is a lot of cooling machinery. The tokamak will also have to have a plumber’s nightmare of piping to retrieve and carry away the heat that’s created, in the form of steam.
There are very few projects with such lengthy commitments. After years of experiments, ITER may reach its goal of producing ten times as much energy as it uses. Then more years will be needed for more research to make the process commercially viable. This long-term approach is welcome in a world that seems to see only the end of the current quarter, or at best the end of the current fiscal year, as the future. We need more of this kind of thinking.
So, fusion is still going to be a part of our future. It’s probably still two or three decades down the road, but by that time we are really going to need it.
As for cold fusion, it’s still out there, too. Just last month two scientists from the University of Bologna, Italy, announced that they had yet another room temperature device that produced more energy than it used. Most scientists are skeptical, as usual. It would really be nice if we could find such a simple process, but if that doesn’t happen, we’ll have to wait on the tokamak.
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