Fusion-energy

The reactions of deuterium, tritium, and helium-3 [14762-55-17, He, having nuclear charge of 1, 1, and 2, respectively, are the easiest to initiate. These have the highest fusion reaction probabiUties and the lowest reactant energies. 

Another set of reactions of practical interest involves only deuterons. The D—D reaction can proceed along either of two pathways with roughly equal probabiUties  

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Plasmas at fusion temperatures cannot be kept in ordinary containers because the energetic ions and electrons would rapidly coUide with the walls and dissipate theit energy. A significant loss mechanism results from enhanced radiation by the electrons in the presence of impurity ions sputtered off the container walls by the plasma. Therefore, some method must be found to contain the plasma at elevated temperature without using material containers. 

Once a fusion reaction has begun in a confined plasma, it is planned to sustain it by using the hot, charged-particle reaction products, eg, alpha particles in the case of D—T fusion, to heat other, colder fuel particles to the reaction temperature. If no additional external heat input is required to sustain the reaction, the plasma is said to have reached the ignition condition. Achieving ignition is another primary goal of fusion research. 

---

Additionally, two other reactors, the international thermonuclear experimental reactor (ITER) for which the location is under negotiation, and the Tokamak Physics Experiment at PPPL, Princeton, New Jersey, are proposed. The most impressive advances have been obtained on the three biggest tokamaks, TETR, JET, andJT-60, which are located in the United States, Europe, and Japan, respectively. As of this writing fusion energy development in the United States is dependent on federal binding (10—12). 

Fusion energy research is also the primary avenue for the development of plasma physics as a scientific discipline. The technologies and the science of plasmas developed en route to fusion power are already important in other appHcations and fields of science (see Plasma technology). 

J. P. Holdren and co-workers. Report of the S enior Committee on Environmental, Safety, and Economic Nspects of Magnetic Fusion Energy, report UCRL-53766, Lawrence Livermore National Laboratory, Livermore, Calif., Sept. 25, 1989. 

---