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Fusion Energy: Step by Step, Closer to Becoming Reality
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장바울
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2014-05-08 13:59:45, 조회 : 2,351 |
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Fusion Energy: Step by Step, Closer to Becoming Reality
Posted on March 20, 2014
John Renesch's picture
Living in San Francisco puts me in relatively close proximity to the world’s largest and most powerful laser facility – the National Ignition Facility (NIF) at Lawrence Livermore Laboratories, about 50 miles east of me. I have been hearing about this experimental facility since it was commissioned in 2009 and became more curious about their progress in developing a carbon-free source of energy since learning that not only have we been unsuccessful lowering the carbon dioxide parts per million but they are continuing to rise!
hohlraum cylinder.jpgCredit: Lawrence Livermore National Lab
Days before I was scheduled for a tour of the Facility, I received an email release from the Worldwatch Institute stating that we are at a \"record high for global greenhouse gas emissions.\" An email from Institute Executive Director Supriya Kumar states, \"Although the parties to the United Nations climate treaty agreed in 2010 that the increase in average global temperature must be kept below [two] degrees Celsius, many projections now put the climate on track for warming that is significantly above that.\" The Institute’s February 6, 2014 newsletter reports emissions are on their way to ten gigatons of carbon, about sixty percent higher than in 1990. Coal and oil account for three quarters of these emissions according to Worldwatch.
While alternative clean energies like solar and wind are coming online, they cannot replace oil and coal as quickly as is needed to prevent significant climate change.
The Prospects of Clean Energy
What I had heard about the experiments at NIF was that they were moving closer and closer to generating more energy than was used to start the fusion process. This is the step needed to underpin the generation of clean energy – with no carbon emissions. It seemed to this non-scientist that this was a horse worth betting on given the promise it might hold for the human race.
So what does \"ignition\" mean and why is in it the name of the Facility? In the words of NIF, ignition \"refers to the moment when a controlled fusion reaction generates more energy than is needed to spark the reaction: as much or more energy ‘out’ than ‘in.’ Achieving ignition would be an unprecedented, game-changing breakthrough for science and could lead to a new source of boundless clean energy for the world.\"
NIF scientists have been taking almost daily experimental \"shots\" – aiming 192 laser beams at a tiny capsule no longer than a dime, as shown in the photo above. The target is positioned in an ignition chamber (see picture below) where all the lasers beams converge. The challenge: to have all 192 beams strike the target within 30 trillionths of a second of one another. Here is a link to a two-minute video of how the process works.
target position.jpg
Target being positioned in the target chamber where 192 lasers will complete their journey.
Credit: Lawrence Livermore National Lab
The Numbers
These experiments enable NIF researchers – for the first time - to study the effects of extreme temperatures, pressures, and densities on matter – effects that naturally exist only in stars and deep inside planets – \"Bringing Star Power to Earth\" as NIF’s tagline reads. Each experimental shot gives scientists a bit more information which enables them to make the finite adjustments to better time the arrival of each beam to the target. And by finite they really mean finite! Trillionths of second! From beginning to end, the total energy of NIF's laser beams grows from one-billionth of a joule to four million joules, a factor of more than a quadrillion. A joule is the energy/work required to produce one watt of power for one second.
Here’s another perspective on the finite-ness from the NIF website:
Every NIF experimental shot requires the coordination of complex laser equipment. In the process, 60,000 control points of electronic, optical, and mechanical devices—such as motorized mirrors and lenses, energy and power sensors, video cameras, laser amplifiers, pulse power, and diagnostic instruments—must be monitored and controlled. The precise orchestration of these parts by NIF’s integrated computer control system will result in the propagation of 192 separate nanosecond (billionth of a second)-long bursts of light over a one-kilometer path length. The beams must arrive within 30 picoseconds (trillionths of a second) of each other at the center of a 10-meter-diameter target chamber, and they must strike within 50 micrometers of their assigned spot on a target measuring less than a centimeter long.
If NIF succeeds in reaching ignition, the world will be one giant step closer to making fusion power plants, which \"produce no greenhouse gas emissions, operate continuously to meet demand, and eliminate the need for spent fuel storage that fission power plants must address. A fusion power plant would also present no danger of a meltdown,\" as NIF points out. \"Because nuclear fusion offers the potential for virtually unlimited safe and environmentally benign energy, the U. S. Department of Energy has made fusion a major priority in the nation’s long-term energy plans,\" states the NIF.
A Step Closer
I invited my FutureShapers business partner Tom Eddington, my long time friend and fellow futurist Peter Russell and my neighbor Marc Meyer, scientist and venture capitalist at Persefon Ventures, to join me. Our guide for the tour was Mike Dunne, Director, Laser Fusion Energy at NIF.
NIF tour.jpg
(L-R) Tom Eddington, Peter Russell, the author, Mike Dunne, Marc Meyer
Our tour took place on Monday, February 10th. We asked Dunne when they anticipate the breakthrough to achieving ignition. He smiled and said, \"Could be next year, next month or tomorrow.\" Two days later, NIF announced a milestone: \"for the first time anywhere, we've gotten more energy out of this fuel than was put into the fuel.\" I soon learned that the announcement concerned progress made months earlier. Their results had to go through peer review and then clear the national security embargo placed on findings from the experiments. Nevertheless, I thought this was fortuitous timing and since Reuters, Scientific American, Wired, NBC News, and Science magazine all ran stories on this milestone on February 12th, I became eager to share it with the futurist community.
In part, Science reported that NIF \"has finally produced some results that fusion scientists can get enthusiastic about…..researchers managed to produce energy yields 10 times greater than produced before and to demonstrate the phenomenon of self-heating that will be crucial if fusion is to reach its ultimate goal of ‘ignition’…\" Scientific American said \"The power of the sun has edged a little closer to Earth...\" Wired wrote \"…\"…a future with fusion power is starting to look more possible.\" Nature online journal reported that NIF is \"crossing an important symbolic threshold on the long path toward exploiting this virtually boundless source of energy.\"
Here’s what Dunne told me by email following our tour and after the story broke: \"This is a world first for any approach to fusion, and so has excited a lot of scientific interest…. Ignition is the ultimate goal of the experiments, so the latest result marks a waypoint (albeit quite significant). The next significant step on the plan is to achieve what we call \"alpha burn\", which is where the fusion output more than doubles the energy input to the fuel, and we pass a particular threshold of energy output (specifically 10,000,000,000,000,000 fusion reactions). We are currently a few percent below this value.\"
Like with climate change, there are the deniers and doubters - critics who scoff at the idea that fusion will ever be possible. One of these self-appointed thorns in the side of the fusion theorists is NYU journalism professor Charles Seife, who posted a comment on the Nature article which announced the recent progress by NIF. Here’s part of what he wrote: \"the relentlessly optimistic stories coming from Livermore for the past few years…..the most impressive advance here is really a milestone in public relations...\" In Slate.com he writes, \"…the history of fusion energy is filled with crazies, hucksters, and starry-eyed naifs chasing after dreams of solving the world’s energy problems.\" Wired suggests that Seife may be a \"fusion atheist\" – a disbeliever who justifies his point of view.
The Vision and the Reality
Planning for NIF began in the early 1990s, and ground was broken on May 29, 1997. The main NIF building was completed in September 2001. Spanning the width of three football fields and standing 10 stories tall. All 192 enclosures for the laser beams were completed in 2003, and the second of NIF’s two laser bays was commissioned in 2008. NIF was officially dedicated on May 29, 2009. It is barely five years old.
4.jpg
Ignition chamber being hoisted and moved to its new home – the NIF target bay - during construction. Credit: Lawrence Livermore National Lab
NIF made history earlier, on July 5, 2012, when its lasers delivered more than 500 trillion watts (terawatts) of peak power and 1.85 megajoules of ultraviolet laser light to its target. The new results are yet another milestone. Dunne pointed out that technology advances similar to computer monitors evolving from cathode ray tubes to flat screens will allow the laser paths and power to be contained in much smaller, more compact facilities when the time comes to build power plants using this technology.
Most everyone involved realizes that fusion power as a practical energy source is a way off yet the promise of a fossil fuel-free world makes it worth the effort to continue the experiments, support the effort not throw stones, and pursue the dream.
Apple founder Steve Jobs narrated the successful 1997 \"Think Different\" ad campaign the company ran, that started with \"Here’s to the crazy ones.\" Visionaries through the ages have been criticized and labeled \"nuts\" and \"starry-eyed.\" It goes with the territory. The ability to hold a vision of what is possible in light of a seemingly adversarial reality has been defined as personal mastery – the ability to endure the creative tension between a vision for how things could be and what really is right now. In my view, the NIF \"crazies\" are holding that vision in spite of the name-calling, and more power to them (pun intended).
[Note: Special thanks to Breanna Bishop, Public Information Officer for the Laboratory, and Lynda Seaver, Deputy Director of the Public Affairs Office, for their help in arranging the tour and providing an escort for us while we were there, and to Mike Dunne for his post-tour support, including reviews of earlier drafts of this article.]
About the author:
John Renesch is a businessman-turned-futurist who has published 14 books and hundreds of articles on organizational and social transformation. He is the principal of Renesch Advisory Services and founder of FutureShapers, LLC.
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