Deuterium-tritium reaction

A sealed-tube neutron generator, utilizing the deuterium-tritium reaction is the source of fast (14 MeV) neutrons, and a 8 x 3 1 Nal scintillation detector, with three optically coupled photomultipliers, is used to measure the >ray signal... 

A Kaman Nuclear Model A711 sealed-tube accelerator for the generation of 14 MEV neutrons by the deuterium-tritium reaction... 

Three promising fusion reactions are D-D (deuterium-deuterium) and D-T (deuterium-tritium) reactions ... 

Neutron generator a deuterium-tritium reaction powered by an accelerator produces neutrons with an energy of 14.1 MeV. Neutron generators have some advantages compared with the other sources they can be switched off and on, they produce a high and exactly defined energy, and they can be used in a pulsed mode. 

The fusion of atomic nuclei is the process that produces energy in the sun. An uncontrolled fusion reaction is the basis of the hydrogen bomb. A controlled fusion reaction could provide an almost unlimited source of energy. The nuclear reaction that holds the most immediate promise is the deuterium-tritium reaction. 

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 result of the cold-fusion epopee that was positive for electrochemistry are the advances in the experimental investigation and interpretation of isotope effects in electrochemical kinetics. Additional smdies of isotope effects were conducted in the protium-deuterium-tritium system, which had received a great deal of attention previously now these effects have become an even more powerful tool for work directed at determining the mechanisms of electrode reactions, including work at the molecular level. Strong procedural advances have been possible not only in electrochemistry but also in the other areas. 

For mechanistic studies => to test some hypothesis about a reaction mechanism or about how a certain organism metabolizes a compound => often need to synthesize a particularly labeled compound (with deuterium, tritium, or C). 

Saunders also used calculations on his model reaction (54) to determine the relationship between the secondary hydrogen-deuterium (secondary hydrogen-tritium) KIEs and secondary deuterium-tritium KIEs for doubly labelled substrates and to investigate how tunnelling affects this relationship. To obtain secondary KIEs that could be checked experimentally, Saunders calculated the secondary k lk% and k lk KIEs for the hypothetical E2 reaction of a pair of doubly labelled substrates [17] and [18]. 

Table 39 The secondary /3-hydrogen/tritium and deuterium/tritium KIEs for the E2 reactions of p-YC CLTCHjX at 50°Ca...

Table 42 The secondary hydrogen-tritium and deuterium-tritium KIEs in the E2 reactions of several arylethyltrimethylammonium bromides at 50oC. ...

Once the dissociative mechanism is established, it is possible to apply Gutmann s theoretical treatment (40) to the elucidation of the rate-determining step of the exchange reaction. For deuterium-tritium double labeling procedures, i.e., D O 100%, TgO 1%, it may be shown that the following normalized equations apply under initial exchange conditions ... 

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

To initiate such a D-T fusion reaction requires temperatures of 10-100 million degrees. Relatively large amounts of deuterium/tritium and/or lithium deuteride can be heated to such temperatures by a fission explosion where the temperature may be 108 K. (Tritium is generated in situ by the neutron bombardment of i during the fusion reaction by the reaction 6Li + n —> 3H + 4He + n + 17 MeV, thus making the overall fusion reaction 6Li + 2H —> 2 4He + 21.78 MeV). 

Tunneling of atomic nuclei in the course of an elementary act of chemical reaction was first considered theoretically in Refs. [5-8] soon after quantum mechanics had been created. It has been shown that nuclear tunneling may lead to unusually large isotope effects for reactions in which light atoms (hydrogen, deuterium, tritium) are transferred and to a decrease in the effective activation energy of chemical processes as the temperature decreases. 

A single muon stopped in a target of deuterium-tritium mixture can catalyze more than 100 fusions, but this number is limited by two major bottle-necks. One is the rate at which a muon can go through the catalysis cycle before its decay (cycling rate), and another is a poisoning process called p-a sticking in which, with a probability u)s < 0.01, the muon gets captured after the fusion reaction to atomic bound states of the fusion product 4He, and hence lost from the cycle (see Section 5). 

Of the several fusion reactions, deuterium tritium fusion is the most feasible, as it has the lowest ignition temperature, 40 million°K. (See Reaction 1.) Deuterium comprises 0.15... 

The fusion reaction least difficult to initiate is the deuterium-tritium (DT) reaction which releases a 14.1 MeV neutron and a 3.5 MeV alpha particle. However, because neutrons activate the reactor structure, other fusion reactions have been considered. These reactions are either neutron free, or they produce fewer and less energetic neutrons. The required quality of confinement for these more desirable fusion reactions is much higher than for DT, and it is not yet clear if it will be achieved. Hence, fusion reactor designers have concentrated on the DT reaction for at least the first generation of fusion plants. 

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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