By Joseph Mcclain
“There’s always been this sense that fusion is fifty years away,” Saskia Mordijck says, but she adds that the horizon for safer and more efficient fusion-based electricity in our homes is really, truly getting closer. Mordijck, a research assistant professor based in the Computer Science Department at William & Mary (with adjunct positions in physics and applied science), has received funding from the U.S. Department of Energy to continue her investigation of fusion energy. She says most people are only vaguely aware of how fusion works and therefore have little idea of the advantages is offers over “traditional” nuclear power.
“Fusion energy is the exact opposite of what we have across the river in Surry where we have a nuclear power plant,” she explained. “In a nuclear power plant they actually bombard their material with small particles so it splits apart so there is energy released—that’s fission.” To accomplish fusion, she says, you take two very small particles and heat them at high enough temperatures so that they fuse together. “As a result of their fusing together they actually will release energy,” Mordijck explained. “This is all in Einstein’s famous equation E=mc2. That’s one most people recognize even if they have not had any physics.”
Many advantages over fission When it comes to power generation, fusion has a number of advantages over fission and many of them relate to safety. Mordijck says that the usual causes of anxiety over nuclear power generation just don’t exist with fusion. Fukushima/Chernobyl-type incidents are not part of the equation. “The nice thing about a fusion reaction is that if somehow it would go out of control, it would just stop itself automatically. If a fission reaction goes out of control, it can really go out of control,” Mordijck explained.
“You can’t stop it and it actually might go into a nuclear meltdown.” Ads by Google The Volkswagen Beetle – View the Iconic & Utterly Unique Volkswagen Beetle at VW.com Now. – www.VW.com/Beetle The second set of fusion-over-fission benefits centers around radioactive waste. Mordijck acknowledges that certain amount of waste is inescapable, but a fusion power plant would generate only a fraction of the amount of nuclear waste that even the most efficient fission plants produce. Not only is the amount smaller, but waste from a fusion plant also stays dangerous for much shorter periods of time. “In a fission power plant we create a lot of radioactive waste which lasts for a very long time. It lasts longer than most things that we have here on Earth, and so we have to store it somewhere. We cannot clean it any way or form,” Mordijck explained.
“Whereas in a fusion power plant, the lifetime of this waste is very short. After 50 to 100 years, it will be completely gone and it will not be more radioactive than the surrounding environment and it won’t be able to contaminate anything.” Funding cuts hinder progress Fusion energy has been working in the sun, where the fusion of hydrogen nuclei into helium has been keeping us warm for years. Despite all the potential advantages, fusion remains an experimental technology and an underfunded one at that, Mordijck says. “When people say that fusion always seems to be perpetually fifty years off, we fusion scientists point out that our funding has been cut every single year, so it’s hard to make any progress,” she noted. Mordijck says that to get fusion past the experimental stage, she and her fellow scientists must solve several problems—scientific and engineering. One of the knottiest sets of problems involves thermal transfer. The challenges begin with the necessity of having something very hot next to something very cold. “So, imagine you’re heating something to temperatures that are hotter than the sun, but two or three feet away you need super-cooling magnets,” she said.
The high temperatures are necessary to induce fusion and the magnets are needed to contain the product of the fusion, a state of matter known as plasma. Once fusion is achieved, the problem becomes how to get the energy out of the plasma. Both coal-fired and fission power plants use the heat generated to boil water to spin turbine blades. Fusion, generating temperatures beyond the sun’s, offers a problem of too much heat too quickly for most materials to handle.