Giant laser to be used in quest for limitless energy
Scientists hope to solve the global energy crisis by harnessing the energy generated by a fusion-generated ‘mini-star’.Posted May 13, 2010
Science fiction meets reality this summer, if all goes as planned, when scientists at Lawrence Livermore National Laboratory launch the first of a series of tests which will attempt to prove that powerful beams of light can produce a controlled fusion reaction. Harnessing the power unleashed through fusion, scientists theorize, could solve the global energy crisis.
The world’s largest laser system, the National Ignition Facility (NIF), will focus the energy of 192 laser beams on a BB-sized target filled with hydrogen fuel. The goal is to fuse the hydrogen atoms’ nuclei and produce net energy gain – the same fusion energy process that makes the stars shine and provides the life-giving energy of the sun.
The experimental phase of the National Ignition Campaign, a series of tests and simulations to prepare NIF for its first nuclear fusion experiments in 2010, has been completed.
Current nuclear power plants use fission technology, or the splitting of atoms to produce energy. Fusion, or the joining of atoms to produce energy, creates less radioactive material than fission, and its supply of fuel can last longer than the sun.Replicating the extreme conditions that foster the fusion process has been one of the most demanding scientific challenges of the last half-century. Efforts to make a fusion reactor to produce electricity have been thwarted by scientists’ inability to control the fusion reaction in a contained space.
Achieving nuclear fusion burn and gain has not yet been demonstrated to be viable for electricity production. For fusion burn and gain to occur, a special fuel consisting of the hydrogen isotopes deuterium and tritium must first “ignite.” A primary goal for NIF is to achieve fusion ignition, in which more energy is generated from the reaction than went into creating it.
How to Make a Small Star
Decades of research and billions of dollars are behind the quest for a miraculous reaction that will occur in less than the blink of an eye. Don’t try this at home.
- Take a hollow, spherical plastic capsule about two millimeters in diameter (about the size of a small pea)
- Fill it with 150 micrograms (less than one-millionth of a pound) of a mixture of deuterium and tritium, the two heavy isotopes of hydrogen.
- Take a laser that for about 20 billionths of a second can generate 500 trillion watts – the equivalent of five million million 100-watt light bulbs.
- Focus all that laser power onto the surface of the capsule.
- Wait ten billionths of a second.
- Result: one miniature star.
By following this recipe, researchers expect to make a miniature star that lasts for only 200 trillionths of a second after it’s ignited. During its brief lifetime, it will produce energy the way the stars and the sun do, by nuclear fusion. The tiny star will produce ten to 100 times more energy than used to ignite it.
The Livermore lab says it could get its fuel — the two isotopes of hydrogen — from seawater.
“One gallon of seawater would provide the equivalent energy of 300 gallons of gasoline; fuel from 50 cups of water contains the energy equivalent of two tons of coal,” the Livermore project’s website says.
Unlike burning coal and natural gas, nuclear power does not produce greenhouse gases.
“We have a very high confidence that we will be able to ignite the target within the next two years,” thus proving that controlled fusion is possible, said Bruno Van Wonterghem, a project manager.
But it will take time
Already over budget and behind schedule, the expected completion date for the current research is now a late 2012. And it will take at least another 20 years, with adequate funding, to develop a continuous fusion reaction that could heat water, create steam and turn generators at a commercial fusion power plant, said Lynda Seaver, spokeswoman for the project.
Critics of fusion research point to this timeline as too long to wait for a solution to the climate challenges we face today. The costs could better be applied to more proven technologies which can be applied sooner.
Researchers at the NIF, however, in anticipation of the upcoming tests, believe they are on the frontier of groundbreaking technology which will bring the long-sought goal of practical fusion energy closer to realization.
For more information, visit the National Ignition Facility website.