For more than 60 years, scientists have dreamed of a clean, inexhaustible energy source in the form of nuclear fusion.
And they're still dreaming.
But thanks to the efforts of the Max Planck Institute for Plasma Physics, experts hope that might soon change.
Last year, after 1.1 million construction hours, the Institute completed the world's largest nuclear fusion machine of its kind, called a stellarator.
They call it this 52-foot wide machine the W7-X.
And following more than a year of tests, engineers are finally ready to fire up the $1.1 billion machine for the first time, and it could happen before the end of this month, Science reported.
The black horse of nuclear reactors
Known in the plasma physics community as the "black horse" of nuclear fusion reactors, stellarators are notoriously difficult to build. The GIF below shows the different layers of W7-X, which took 19 years to complete:
Between 2003 and 2007, as the project was being built, it suffered some major construction set backs — including one of its contracted manufacturers going out of business — that nearly canceled the whole endeavor.
Only a handful of stellarators have ever been attempted, and even fewer have been completed.
By comparison, the more popular cousin to the stellarator, called a tokamak, is in wider use. There are over 3 dozen operational tokamaks across the globe, and more than 200 built throughout history. These machines are easier to construct and, in the past, have proven to do the job of a nuclear reactor better than the stellarator.
But tokamaks have a major flaw that W7-X is reportedly immune to, suggesting that Germany's latest monster machine could be a game-changer.
How a nuclear reactor works
image: https://static-ssl.businessinsider.com/image/563381579dd7cc1b008c6130-800-450/tokamak_(scheme).jpg
.jpg)
Uploaded by Matthias W Hirsch on Wikipedia
Schematic of the average tokamak. Notice how it has fewer layers than the stellarator and the shape of the magnetic coils is different.
The key to a successful nuclear reactor of any kind is to generate, confine, and control a blob of super-heated matter, called a plasma — a gas that has reached temperatures of more than 180 million degrees Fahrenheit.
At these blazing temperatures, the electrons are ripped from their atoms, forming what are called ions. Under these extreme conditions, the repulsive forces, which normally make ions bounce off each other like bumper cars, are overcome.
Consequently when the ions collide, they fuse together, generating energy in the process, and you have what is called nuclear fusion. This is the process that has been fueling our sun for about 4.5 billion years and will continue to do so for another estimated 4 billion years.
Once engineers have heated the gas in the reactor to the right temperature, they use super-chilled magnetic coils to generate powerful magnetic fields that contain and control the plasma.
"The world is waiting to see if we get the confinement time and then hold it for a long pulse," David Gates, the head of stellarator physics at the Princeton Plasma Physics Laboratory, told Science.
Source: http://www.businessinsider.my/germany-is-turning-on-its-monster-stellarator-2015-10/
----Shared via feedly
.jpg){kind=link}