Daniel Clery in ScienceNOW Daily News:
A $12 billion worldwide attempt to generate power from nuclear fusion was signed into existence today by ministers from the project’s seven international partners–China, the European Union, India, Japan, Korea, Russia, and the United States. The International Thermonuclear Experimental Reactor (ITER) project has been 2 decades in the making, and with today’s signing, construction of the reactor in southern France can begin next year.
Nuclear fusion is the process that powers the sun and stars. It happens when atomic nuclei slam together with such force that they fuse together into a larger nucleus, releasing a small portion of the mass of the original nuclei as a tremendous amount of energy. In ITER, the nuclei used will be deuterium and tritium–isotopes of hydrogen–which can be extracted in almost limitless quantities from seawater. Running a fusion reactor creates a small amount of short-lived radioactive waste that decays away in around a century; high-level waste from traditional nuclear reactors can stick around for thousands of years.
But fusion is no easy matter: The nuclei must be heated to 100 million degrees, and the resulting ionized gas, or plasma, held in place with huge and powerful superconducting electromagnets to prevent it from touching the sides of the vessel, a doughnut-shaped steel enclosure called a tokamak. It takes a huge amount of energy to get the plasma into this state, and the goal for ITER researchers is to demonstrate that they can control the fusion reaction and generate 10 times as much power as the reactor consumes.