Nuclear Fusion: Simulation Shows Potential

Experimental nuclear fusion reactor is seen at a laboratory in the Southwest Institute of Physics in Chengdu, Sichuan Province April 15, 2011.

High-gain nuclear fusion could soon be a possibility according to new computer simulations.

A series of computer simulations performed at Sandia National Laboratories revealed that a fusion reactor can release an output of energy that is greater than the energy fed into the reactor.

The method being tested at Sandia appears to be 50 times more efficient to drive implosions of targeted materials to create the fusion reaction.

Nuclear fusion occurs when two atoms fuse together to form a heavier atom. This process releases a vast amount of energy. However nuclear fusion only occurs naturally at incredibly high temperatures like the center of a star.

Even though the process has been impossible to recreate in Earth, scientists have been studying ways to make nuclear fusion possible because nuclear fusion is a very attractive power source since the fuel is free and the process releases massive amounts of energy.

Scientists have looked at two competing approaches for the artificial creation of nuclear fusion: magnetic confinement and inertial confinement.

Magnetic confinement uses magnetic force to contain the fusing plasma within a device while inertial confinement uses lasers to trigger the fusion process.

Magnetic confinement is being used in the 500-megawatt ITER fusion reactor in France while inertial confinement is being used in California's National Ignition Facility.

Magnetic confinement is regarded as the better alternative and according to the computer simulations performed at Sandia the method is more efficient as well.

The researchers at Sandia are testing a method called magnetized inertial fusion in which two coils generate a magnetic field that confines the fusion reaction.

A metal cylinder lines the insides of each of the coils. The cylinder has a metal liner of deuterium and tritium which is then hit with a current of tens of millions of amperes. The current destroys the liner but it generates a strong magnetic field.

"People didn't think there was a high-gain option for magnetized inertial fusion but these numerical simulations show there is," said Sandia researcher Steve Slutz, the paper's lead author. "Now we have to see if nature will let us do it. In principle, we don't know why we can't."

The computer simulations showed that the output was 100 times that of 60 million amperes put into the system. Actual tests are necessary to validate the computer simulations and they are already under way at Sandia. A laboratory result is expected by late 2013.

The work was reported in the January 13 issue of Physical Review Letters and was supported by Sandia's Laboratory Directed Research and Development office and by the National Nuclear Security Administration.