Fusion Energy - Will it Really Happen?
Perhaps you remember Dr. Emmett Brown's vehicle in the "Back to the Future" movies? It was powered by a fusion energy device small enough to fit in the vehicle's trunk. Perhaps you also looked at this device and said, "When can I get one of those"? (Or maybe you just looked at the Delorean longingly.)
Will fusion energy really happen? Do we want it to happen? The reply is a few years away. A project exists referred to as "ITER", (Latin for "the way") which could add to the hopes of the world for a clean, environmentally safe, abundant energy source. Currently in the planning stages, this project will plan, build and operate a fusion reactor that represents a necessary step in the understanding of how to harness fusion energy to produce electricity. This includes proving the feasibility of a prolonged fusion reaction and determining if ITER will produce more power than it consumes (critical to a sustained fusion reaction). Past and current reactors have approached this hurdle but the work done at ITER will play an important part in meeting and then surpassing this goal. The step beyond that is to design and build a commercial fusion plant to produce electricity based on ITER's findings.
The site for the ITER project is in Cadarache, France and the organization that oversees ITER has representatives from China, the European Union, India, Japan, Korea, Russia and the United States. This organization has agreed to share responsibilities for the project including costs, design, licensing, construction, etc. It is estimated that the project will cost about five billion Euros to construct and another five billion Euros to operate over its intended twenty-one year life span. As stated before, the reply to fusion really happening is a few years away: the first plasma is tentatively scheduled to be generated in 2018 and then the reactor is expected to operate and conduct research for 10 years beyond that (after about a year to "fine tune" the process). From the beginning, the ITER reactor is intended to be a learning process where, once in operation, researchers can understand and improve the way the reactor operates so that the commercial reactors that result from this are safe and efficient.
What is fusion? Here is a very basic description: The nuclear reaction that most people are familiar with is "fission" where the nuclei of heavy atoms (Uranium U235 is probably the most common) are split into lighter atoms releasing energy as heat. Conventional nuclear reactors use this heat to make steam to run turbines that generate electricity. Fusion is the same power source used by suns and stars and it is roughly the opposite of fission. A fusion reaction is where the nuclei of lighter atoms fuse together forming heavier atoms (for ITER it is helium) and also releasing energy. The proposed reactor for the ITER project will utilize a "tokamak" design which uses strong magnetic fields to confine fusion plasma (a gas kept at a high temperature and proper density where the reactions take place) and allow control of the fusion reaction. The heat from the energy given off as a result of the fusion reaction can be used in a similar manner to conventional reactors to provide electricity.
As for the "Do we want it to happen?" Here are some reasons fusion could be a viable energy source for the world:
1. The fuel for fusion reactors (deuterium and lithium) is plentiful (several billion years worth) and easy to reach. Deuterium comes from saltwater and lithium is found in the earth's crust.
2. Radioactive fuel does not need to be transported to the reactor. That part of the fuel is generated on site by combining other materials and is in very small quantities.
3. There are no greenhouse gasses given off as a by-product of this process.
4. The reactor is designed so that an out-of-control chain reaction is not possible. Only a small amount of fuel is present in the reactor at any time.
5. One fusion reactor facility could power two million homes. By the time the first commercial reactors come on line that will probably be improved (in conjunction with other research including superconducting materials).
6. The radiation given off by this reaction is not nearly as harmful as with a fission reaction and shielding for it is much easier.
7. Yes, there is nuclear waste but it has a half life (basically the time until it is no longer radioactive) of 50 to 100 years. It is the parts in the reactor that are irradiated and they could potentially be reused over time.
8. The heavy atoms by-product of the fusion process is helium.
9. As stated earlier, countries from around the world are working together / cooperating to find a viable source of energy.
Given the current ITER timeline, a trip to the future may be the only way some of us will get to see fusion power as a reality.