Don’t Get Too Excited About This Nuclear Fusion Breakthrough
It’s big, big news that scientists have recently been able to run a nuclear fusion reaction that releases more energy than it consumes . It is also true that this type of reaction has the potential to be a useful source of energy in the future. Or, as physicists like to say, the last 50 or so years before useful nuclear fusion was “10 years away.” Read on to learn more about why scientists are excited, as well as why our homes are likely to be powered by the same power plants for a long time to come.
Is nuclear fusion the same as nuclear power?
Nuclear power plants and nuclear bombs use a fission reaction, which is different from the fusion reaction that was recently reported in the news. Fission occurs when an atom splits. Usually you start with a uranium or plutonium atom, hammer a neutron into it, and split that atom into several pieces, which can then break into even more pieces. Fission releases energy in the form of heat, and nuclear power plants use this heat to boil or vaporize water . There are no emissions from nuclear power, but there is the inconvenient problem of nuclear waste—those smaller atoms that are still radioactive.
Nuclear fusion is a reverse reaction: smaller atoms combine to form one larger one. This is an exciting opportunity because it produces no carbon emissions and does not create radioactive waste problems.
Thus, thermonuclear fusion can be a waste-free and non-emission source of energy?
This is a dream. We know that fusion reactions can create energy because the Sun does this all day long. It fuses hydrogen atoms so that they become helium (helium atoms are twice the size of hydrogen). Fusion reactions are what create the sun’s heat and light. Mergers happen so easily on the Sun because of extreme temperatures and gravity; making it happen on Earth is much more difficult.
Fortunately, at least hydrogen is easy to find; it is the most abundant element in the universe . Instead of coal mined from underground, a fusion reactor could use deuterium (heavy hydrogen) as its main fuel from sources as numerous as water. According to CNN, a glass of tap water contains enough deuterium to theoretically power a home for a year. You’ll also need tritium, a rarer form of hydrogen, but finding fuel isn’t the main problem.
The difficulty lies in the fact that a lot of energy is required to carry out the fusion reaction. Scientists have been able to fuse atoms before, but until this week, the reaction has always consumed more energy than it produces, which is the opposite of what you need an energy source for.
What happened during the breakthrough at the National Ignition Center?
For the first time, scientists have managed to initiate a thermonuclear reaction that creates more energy than it uses up . Like, like, something like. Big disclaimer on this one.
Technically, the reaction created more energy than the laser energy that powered it. But if you compare the output of the reaction with the entire electricity bill of the plant, it’s a different story: the lasers delivered 2.05 megajoules of energy to the reaction, and the reaction produced 3.15 megajoules of output. But these lasers themselves consume a lot of electricity – about 300 megajoules.
The entire reaction apparatus was neither cheap nor easy to assemble. In addition to hydrogen, gold, uranium and diamonds were also involved, and it took researchers months to figure out the exact shape of the diamond part.
Scaling this process up to the size of a power plant is unlikely to be possible in the near future. Science Magazine reports that another type of reactor, called a tokamak, is considered the best choice for practical power generation, but the main facility in France to work on tokamak fusion is “significantly over budget, long overdue, and won’t break even until late 2030″. th years”. So we’ll wait a little longer for our space age energy source.