Thermonuclear fusion

Atomic (or Nuclear) Bomb. A weapon invented during WWII and developed in the United States as a joint effort with the British and Canadian governments. It utilizes for its destructive effect the energy of an Atomic or Nuclear Explosion (qv). Since atomic explosions are of two types, fission and fusion, atomic bombs are of. corresponding types. However, it has been necessary to first initiate an atomic explosion with a nuclear fission reaction in order to bring about the conditions under which a nuclear fusion(thermonuclear) reaction can occur. 

The hydrogen bomb uses a similar type of fusion reaction as its source of energy. A conventional nuclear fission bomb is used as the heat source to start the fusion (thermonuclear) reaction. It may some day be possible to ignite a thermonuclear bomb reaction without a fission bomb, but at this time, no one has a practical notion as to how it might be accomplished. As a result, fusion reactors cannot lead to the production of hydrogen bombs. 

Define nuclear fusion, thermonuclear reaction, and plasma. 

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). 

Laser-Assisted Thermonuclear Fusion. An application with great potential importance, but which will not reach complete fmition for many years, is laser-assisted thermonuclear fusion (117) (see Fusion energy). The concept iavolves focusiag a high power laser beam onto a mixture of deuterium [7782-39-0] and tritium [10028-17-8] gases. The mixture is heated to a temperature around 10 K (10 keV) (see Deuterium AMD tritium). At this temperature the thermonuclear fusion reaction... 

Although practical generation of energy by laser-assisted thermonuclear fusion remains well ia the future, the program has provided some of the most exacting requirements for laser technology and has led to advances ia laser equipment that have been adopted ia other areas. Thus the research and development associated with thermonuclear fusion work has helped to spur advances ia laser technology useful for many other appHcations. 

Tritium is produced in heavy-water-moderated reactors and sometimes must be separated isotopicaHy from hydrogen and deuterium for disposal. Ultimately, the tritium could be used as fuel in thermonuclear reactors (see Fusionenergy). Nuclear fusion reactions that involve tritium occur at the lowest known temperatures for such reactions. One possible reaction using deuterium produces neutrons that can be used to react with a lithium blanket to breed more tritium. 

Controlled thermonuclear fusion experiments and certain types of confined arcs known as pinches have temperatures in the 5 x 10 -10 K range. However, to be successhil, controlled thermonuclear fusion needs to take place from 6 x 10 -10 K. In fact, the goal of all fusion devices is to produce high ion temperatures in excess of the electron temperature (10). 

Pulsed plasmas containing hydrogen isotopes can produce bursts of alpha particles and neutrons as a consequence of nuclear reactions. The neutrons are useful for radiation-effects testing and for other materials research. A dense plasma focus filled with deuterium at low pressure has produced 10 neutrons in a single pulse (76) (see Deuterium AND TRITIUM). Intense neutron fluxes also are expected from thermonuclear fusion research devices employing either magnetic or inertial confinement. 

Most modem projectiles and virtually all missiles contain explosives. The plasmas that result from explosives are intrinsic to operation of warheads, bombs, mines, and related devices. Nuclear weapons and plasmas are intimately related. Plasmas are an inevitable result of the detonation of fission and fusion devices and are fundamental to the operation of fusion devices. Compressed pellets, in which a thermonuclear reaction occurs, would be useful militarily for simulation of the effects of nuclear weapons on materials and devices. 

K. Bockasten and co-workers. Controlled Thermonuclear Fusion Research, International Atomic Energy Agency, Vieima, Austna, 1961. 

Much of the world s separated plutonium has been used for nuclear weapons (Table 1). It is probable that 5 kg or less of Pu is used in most of the fission, fusion, and thermonuclear-boosted fission weapons (2). Weapons-grade plutonium requires a content of >95 wt% Pu for maximum efficiency. Much plutonium does not have this purity. 

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