Harnessing nuclear fusion for power sounds like a dream come true. Not only would it result in zero emissions or greenhouse gases, but it also offers a supply of power that never ends.
However, nuclear fusion power has never been economically viable and generally costs more to create than what it would take in, especially when compared to natural gas and coal power.
A team of scientists from the University of Washington, though, have solved the problem. Their concept nuclear fusion reactor produces the same output as a coal factory, but at a lower cost.
Nuclear fission, the process behind today's nuclear facilities, involves splitting an atom into smaller atoms. This releases a large amount of energy, and unfortunately, sometimes creates disaster when something goes wrong, such as the meltdown at Fukushima that happened after a large tsunami hit it.
However, fusion involves combining, or fusing, two atoms into a larger atom. This process also releases energy and happens naturally in stars, such as our sun. This process does not release radioactive particles, so it's a safer and cleaner form of energy.
The UW team's design for a fusion reactor builds upon what we already know about fusion, which requires a magnetic field that holds plasma in place while fusion occurs. That plasma burns and continuously stays heated, which means that the reactor is self-sustaining. The heat also warms up a coolant, which makes a turbine start up, generating electricity.
The key factor is the UW team's magnetic field. Current methods, like ITER, the International Thermonuclear Experimental Reactor in France, create the field by using large coils that exist outside of the reactor. However, the UW reactor generates its fields by targeting electricity back into the plasma. This means that their reactor requires less building materials and is more efficient.
"This is a much more elegant solution because the medium in which you generate fusion is the medium in which you're also driving all the current required to confine it," says Derek Sutherland, a doctoral student at the University of Washington.
But exactly how efficient is the UW team's fusion reactor? Given that most nuclear fusion reactor concepts end up costing much more than current power sources, the team's results are exciting. After doing an analysis of the cost of building a full-size fusion reactor capable of producing 1 billion watts of power, the team estimated the price at $2.7 billion. A coal power plant producing that amount of power, though, costs $2.8 billion.
The current prototype of this concept is only about 10 percent the size of a full-sized reactor, but in tests, it operated as expected. Further tests, while expanding the reactor's size. are underway.
