D-T reaction

Deuterium—deuterium reactions are harder to ignite and yield less energy than D—T reactions, but eventually should be the basis of fusion energy production (172). Research into the production of fusion power has been ongoing since the 1950s (173—177) (see Eusion energy). 

In the plasma 8Q% of the energy produced by the D-T reactions is in the form of energetic NEUTRONS which escape across the magnetic field and are then trapped in a surrounding blanket which contains LITHIUM. 

Candlin, J. P., Taylor, K. A., Thompson, D. T. Reactions of Transition Metal Complexes. Amsterdam Elsevier 1968. 

The peak reaction rate coefficient of the D-D reaction is consideiably less than that of the deuterium-tritium (D-T) reaction occurring within the (D-D) cycle. Thus, attention tends to focus on the latter. Because tritium does not occur naturally, the reaction must be supplemented by one using lithium to reproduce the trihum fuel ... 

The D-T reactor is technologically more complex than the D-D reactor because of the need to facilitate the second reaction (which takes place outside the plasma) and because very energetic neutrons must be slowed down to allow the reaction with lithium to lake place. However, the conditions needed to achieve net power output are less demanding than for the D-D fuel reactor. The D-T reaction will probably be exploited first, but its ultimate, very long term use may be limited by the availability of lithium. See also Lithium (For Thermonuclear Fusion Reactors). 

A Cockcroft-Walton accelerator produces 400-keV protons. What is the maximum energy of the neutrons that can be produced with this accelerator using the d+T reaction ... 

It should be noted that commercial neutron generators are also easily adopted to the generation of 2.8 MeV neutrons produced by the 2H(2H,w)3He reaction. In most cases it is merely necessary to replace the tritium target with one containing occluded deuterium. The neutron yield from this reaction is much less than for the D—T reaction and the useful flux is often not much greater than could be obtained by use of isotopic sources. About 35 elements have been found to possess reasonably high (n,n y) or (n,y) cross sections for 2.8 MeV neutrons 41>. Since the 8 most common elements in the earth s crust are not among those readily activated, there is some potential application of 2.8 MeV neutrons in analyses for certain elements in minerals and ores, where major element interferences via 14 MeV activation may be a problem. 

Thermonuclear reactions between deuterons (D-D reaction), between deuterons and tritons (D-T reaction), and between tritons (T-T reaction), respectively, have appreciably higher cross sections than those between protons (P-P reaction) they are therefore of special interest ... 

The cross sections of the D-D and D -T reactions are plotted in Fig. 8.25 as a function of the energy of the deuterons. From this figure it can be concluded that energies of the order of lOkeV (corresponding to temperatures of the order of 10 K) arc needed to get these thermonuclear reactions going and to produce utilizable energy. The starting temperature for the D-T reaction is about 0.5 10 K and that for the D-D reaction about 5 10 K. 

Figure 8.25. Cross sections of the D D and D-T reactions as a function of the energy of the deuterons. (According to A. S. Bishop Project Sherwood The U.S. Program in Controlled Fusion. Addison-Wcslcy Publ. Comp., Reading, Mass., 1958.)...

The two nuclear reactions now most commonly used for power production purposes are designated as D-D and D-T reactions. The former stands for deuterium-deuterium and involves the combination of two deuterium nuclei to form a helium-3 nucleus and a free neutron. The second reaction stands for deuterium-tritium and involves the combination of a deuterium nucleus and a tritium nucleus to produce a helium-4 nucleus and a free neutron. The most common form of an inertial confinement machine, for example, uses a fuel that consists of equal parts of deuterium and tritium. 

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