Development of alternative MFE concepts with potential advantages is also an important part of the fusion program. The fusion program also should include sufficiently broad components of basic research, supporting technology, and engineering to permit the development of the mainline concepts and, at a lower level, several other promising confinement and heating approaches. Over time, the costs of the international research and development for fusion will be a tiny fraction of the total expenditures for world-wide energy use. Under such conditions, the repulsive electrostatic forces that keep positively charged nuclei apart can be overcome and the nuclei of select light elements can be brought together to fuse and form other elements. Nuclear fusion of light elements releases vast amounts of energy and is the fundamental energy-producing process in stars.
Some fusion reactions are easier to produce than others.
Some products of the various fusion reactions are more desirable than others. A helium nucleus and a neutron are the products of this fusion reaction. Extraction of the deuterium fuel is inexpensive. Tritium is radioactive and is not naturally available in useful amounts, but it can be produced in quantity by capturing fusion product neutrons in lithium-bearing components of the fusion machine itself. Lithium is a plentiful element available in the Earth's crust.