The information on this page was prepared by:
| David Kalir | kalir@usc.edu | Civil/Environmental Engineering |
Nuclear Fusion
The process of fusion is what powers the sun and stars. Whereas the fission process that powers nuclear reactors works by splitting atoms with a neutron, fusion power makes use of the energy released when two smaller atoms bond together to form a larger one. The energy here is given off in the form of heat and radiation.
Though the fusion process can be performed with many types of atoms, in order to make the process efficient and respect economic limitations two isotopes of hydrogen would be used, Deuterium and Tritium. Deuterium is present in about one in 800 hydrogen atoms, while Tritium can be formed from Lithium, one of the most common elements in the Earth’s lithosphere.
The operation behind fusion would require the elements to be in the matter phase of plasma, which is above the gas phase in terms of energy. Since this is a very high-energy state, it cannot be contained using regular materials. There are three main ways to confine these extremely hot plasmas: magnetic, which makes use of magnetic fields 100,000 times that of the earth’s magnetic field arranged in a manner to prevent the charged particles from leaking out (“magnetic bottle”); Inertial, which makes use of extremely high energy particle beams or lasers to compress the fusion fuel; and lastly, Gravity, which confines the fuel in extraterrestrial bodies such as the sun and stars.
As of the present, a device known as a “tokamak” seems to be the most promising for fusion technology. Tokamak is an acronym derived from the Russian words “toroid kamera magnit katushka” which translates to “the toroidal chamber and magnetic coil.” The tokamak is a donut-shaped device that channels a current of up to several million amperes. The plasma contained is heated to temperatures of over one hundred million degrees centigrade by high-energy particle beams of radio frequency waves. As a quick note of comparison, the sun burns at ~6000 degrees centigrade.