Our current nuclear (called fission) power has a little sibling, who just might be able to power the world safely one day when he grows up. This reaction, known as fusion, is the same type of energy we get from the sun’s. The idea of fusion as a viable power source is a popular one because a fusion plant operation produces no emissions, fuel sources are potentially abundant, and it produces relatively little (and short-lived) radioactive waste. But it still faces a lot of hurdles before it can come to market. Fusion could be the universal, green power source that the world needs.
The Alcator C-Mod reactor, which was originally created back in 1993, has the highest magnetic field and the highest plasma pressure of any fusion reactor in the world. In addition it is the largest fusion reactor operated by any university.
One of the most vexing issues facing those trying to construct a fusion plant is making sure that it can produce more power than it consumes, something never achieved even in lab experiments. The main issue is how one would propel the hot plasma (an electrically charged gas) around inside the donut-shaped reactor chamber. This is necessary to keep it from losing its heat of millions of degrees to the cooler vessel walls. Now, the MIT scientists think they may have found a way.
Thanks to two brillant researchers we may not only have that solution, but also have the ability to make the process more stable. Those researchers are physicist Yijun Lin and principal research scientist John Rice. They have led experiments that demonstrate a very efficient method for using radio-frequency waves to push the plasma around inside the vessel, not only keeping it from losing heat to the walls but also preventing internal turbulence that can reduce the efficiency of fusion reactions.
Lin says that “some of these results are surprising to theorists,” and as yet there is no satisfying theoretical foundation for why it works as it does. But the experimental results so far show that the method works, which could be crucial to the success of ITER and future power-generating fusion reactors. Lack of a controllable mechanism for propelling the plasma around the reactor “is potentially a showstopper,” Rice says, and the ITER team is “very concerned about this.”
One of these is a method developed by Dennis Whyte and Robert Granetz for preventing a kind of runaway effect that could cause severe damage to reactor components. When a fusion reactor is in operation, any disruption of the magnetic field that confines the super-hot plasma could cause a very powerful beam of “runaway electrons,” with enough energy to melt through solid steel. This would not be dangerous to personnel because everything is well-shielded, but it could cause hardware damage that would be expensive and time-consuming to repair.
So, its not perfect yet, but its a step in the right direction.