Published on June 25th, 2008 | by Stephanie Evans2
Fusion Energy as Alternate Power
For all of the controversy that surrounds nuclear power, it is impossible to deny its vast energy potential. Incidents like Hiroshima, Nagasaki, Chernobyl, and Three Rivers tend to stick in people’s minds and provide ammunition for opponents of nuclear power.
However, for all of the skeptics, there are those who view nuclear power as a long-lasting, perfectly clean source of energy. France, for example, generates about 75% of its electricity through nuclear fission, and can boast the cleanest air of any industrialized nation, as well as the cheapest electricity in Europe.
While some countries have mastered the destructive power of both nuclear fission and nuclear fusion, only fission has been harnessed as an energy source. In 1970, General Atomics predicted that fusion reactors would be online by the year 2000. This goal has proved elusive. There have been numerous setbacks in the development of a fusion reactor, but the benefits of deriving energy from nuclear fusion are too great to cease research and development.
An efficient nuclear fusion reactor—that can sustain a continued reaction and has a greater energy output than input—would be one of the greatest technological advances in history. This achievement would be truly world changing—ending the energy crisis as we know it, and eliminating the majority of greenhouse gasses responsible for global warming. Nuclear fusion provides all of the benefits of nuclear fission, with very few of the costs.
How Fusion Works
Fission creates energy by splitting the atom, and requires heavy metals—metals heavier than lead—as a fuel source. Fusion is about fusing two atoms together using light nuclei, generally variations of hydrogen.
When the atoms merge, the final product, helium, has slightly less mass than the two initial hydrogen atoms. As Einstein discovered, mass has energy. The mass lost in the fusion reaction is what creates energy, generally in the form of heat, which is used to power a steam turbine and create electricity.
The most promising reactor design is called the tokamak reactor, which has succeeded in producing energy in short bursts. For a fusion reaction to be sustained, plasma inside the reactor must be heated to extreme temperatures, not unlike the stars where the process occurs naturally.
Heretofore, the largest obstacle in creating a viable fusion reactor is successfully maintaining the levels of heat required to sustain the reaction for long periods of time. The ultimate goal of fusion is to create enough energy to maintain the temperature of one hundred million degrees Celsius, which can sustain a prolonged reaction. Otherwise, only short bursts can be achieved.
Fusion vs. Fission
There are a few distinct differences between nuclear fission and fusion that make fusion worth pursuing:
- The primary difference is that fusion creates far less radioactive waste, and the waste it does produce is only dangerous for about fifty years. In contrast, fission creates a lot of waste that remains radioactive for tens of thousands of years. This, perhaps, is the greatest setback of nuclear fission.
France admits that they will have to put fission energy on hold if they cannot come up with a solution to make radioactive waste safe, and there is an ongoing debate within the U.S. as to where waste should be stored. The proposal to store radioactive material in Nevada’s Yucca Mountain in sealed bins was rejected. There is only so much room to store this waste, and it is questionable whether current storage techniques can remain leak-proof for centuries.
- Another benefit of fusion is that there are almost no associated safety risks. Once a fission reaction begins, it is self sustaining. If a problem occurs, it is difficult to stop the reaction, as Chernobyl testifies to. On the other hand, a fusion reaction is dependent on a number of factors, largely heat, to be self-sustaining. During a malfunction, the plasma in the reactor would cool and the reaction would stop. Fusion energy brings the risk of a meltdown to zero.
- Finally, the fuel needed for a fusion reactor is in abundance, and cannot be used to make weapons. Heavy metals such as Uranium and Plutonium are used to make nuclear bombs, and nuclear weapons research can be disguised as a nuclear power facility. Two variations of the hydrogen atom are used as fuel in a fusion reaction, deuterium and tritium. Deuterium can be extracted from our inexhaustible supply of seawater, and tritium is produced from lithium, which is also found in abundance.
The Future of Fusion
Unfortunately, scientists are not close to creating a self sustaining, energy-efficient fusion reactor. Most estimates site a fifty to one hundred year time frame for the first working fusion reactor to be online.
Currently, the ITER organization, in conjunction with JET (Joint European Torus) are working on the ITER device, the next generation tokamak reactor. Their goal is to create a fusion reaction that produces more energy than it consumes, test the newest technology for fusion power plants, and improve techniques for the extraction of tritium from lithium. The design of the ITER device is currently being explored, and they project that the first reaction will be possible in 2016.