Nuclear fusion

Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium (hydrogen isotopes), combine to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released.

This article is about the nuclear reaction. For its use in producing energy, see Fusion power. For the journal, see Nuclear Fusion (journal). For the song, see Nuclear Fusion (song).

A nuclear fusion process that produces atomic nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have a relatively small mass and a relatively large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while the fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is endothermic. The opposite is true for the reverse process, called nuclear fission. Nuclear fusion uses lighter elements, such as hydrogen and helium, which are in general more fusible; while the heavier elements, such as uranium, thorium and plutonium, are more fissionable. The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.

uses small amounts of antimatter to trigger a tiny fusion explosion. This has been studied primarily in the context of making nuclear pulse propulsion, and pure fusion bombs feasible. This is not near becoming a practical power source, due to the cost of manufacturing antimatter alone.

Antimatter-initialized fusion

was reported in April 2005 by a team at UCLA. The scientists used a pyroelectric crystal heated from −34 to 7 °C (−29 to 45 °F), combined with a tungsten needle to produce an electric field of about 25 gigavolts per meter to ionize and accelerate deuterium nuclei into an erbium deuteride target. At the estimated energy levels,^[26] the D–D fusion reaction may occur, producing helium-3 and a 2.45 MeV neutron. Although it makes a useful neutron generator, the apparatus is not intended for power generation since it requires far more energy than it produces.^[27]^[28]^[29]^[30] D–T fusion reactions have been observed with a tritiated erbium target.^[31]

Pyroelectric fusion

(hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes. The concept dates to the 1950s, and was briefly advocated by Hans Bethe during the 1970s, but largely remained unexplored until a revival of interest in 2009, due to the delays in the realization of pure fusion.^[32]

Nuclear fusion–fission hybrid

carried out at Los Alamos National Laboratory (LANL) in the mid-1970s, explored the possibility of a fusion power system that would involve exploding small hydrogen bombs (fusion bombs) inside an underground cavity. As an energy source, the system is the only fusion power system that could be demonstrated to work using existing technology. However it would also require a large, continuous supply of nuclear bombs, making the economics of such a system rather questionable.

Project PACER

also called sonofusion was a proposed mechanism for achieving fusion via sonic cavitation which rose to prominence in the early 2000s. Subsequent attempts at replication failed and the principal investigator, Rusi Taleyarkhan, was judged guilty of research misconduct in 2008.^[33]

Bubble fusion

. NuclearFiles.org. Archived from the original on 28 September 2006. Retrieved 12 January 2006.

"What is Nuclear Fusion?"

S. Atzeni; J. Meyer-ter-Vehn (2004). (PDF). The Physics of Inertial Fusion. University of Oxford Press. ISBN 978-0-19-856264-1. Archived from the original (PDF) on 24 January 2005.

"Nuclear fusion reactions"

G. Brumfiel (22 May 2006). "Chaos could keep fusion under control". . doi:10.1038/news060522-2. S2CID 62598131.

Nature

(9 November 2006). "Should Google Go Nuclear? Clean, Cheap, Nuclear Power". Google TechTalks. Archived from the original on 26 April 2007. Retrieved 18 April 2007.

R.W. Bussard

A. Wenisch; R. Kromp; D. Reinberger (November 2007). (PDF). Austrian Institute of Ecology. Archived (PDF) from the original on 26 January 2021. Retrieved 8 October 2008.

"Science or Fiction: Is there a Future for Nuclear?"

M. Kikuchi, K. Lackner & M. Q. Tran (2012). . International Atomic Energy Agency. p. 22. ISBN 9789201304100. Archived from the original on 8 December 2015. Retrieved 8 December 2015.

Fusion Physics

R.K. Janev, ed. (1995). . Springer US. doi:10.1007/978-1-4757-9319-2. ISBN 978-1-4757-9319-2. Archived from the original on 16 January 2023. Retrieved 16 January 2023.

Atomic and Molecular Processes in Fusion Edge Plasmas

– A repository of documents related to nuclear power.

NuclearFiles.org

Annotated bibliography for nuclear fusion from the Alsos Digital Library for Nuclear Issues

Archived 26 October 2020 at the Wayback Machine