Deuterium Tritium

A simple example occurs with hydrogen, which occurs naturally as three isotopes (hydrogen, deuterium, tritium), all of atomic number 1 but having atomic masses of 1, 2, and 3 respectively. 

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. 

Properties of Light and Heavy Hydrogen. Vapor pressures from the triple point to the critical point for hydrogen, deuterium, tritium, and the various diatomic combinations are Hsted in Table 1 (15). Data are presented for the equiUbrium and normal states. The equiUbrium state for these substances is the low temperature ortho—para composition existing at 20.39 K, the normal boiling point of normal hydrogen. The normal state is the high (above 200 K) temperature ortho—para composition, which remains essentially constant. 

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... 

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 40 The primary and secondary deuterium-tritium and hydrogen-tritium KIEs for the oxidation of benzyl alcohol to benzaldehyde with NAD+ and yeast alcohol dehydrogenase at 25°C.a...

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 ... 

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

NADH-dependent reductase, thus allowing the biopterin cofactor to function catalytically (72JBC(247)6082). That the conversion of phenylalanine to tyrosine involves an arene oxide intermediate is suggested by the observation of the so-called NIH shift phenomenon (i.e. migration and retention of the para substituents such as deuterium, tritium, methyl and bromine when these para-substituted phenylalanines are enzymatically hydroxylated) <66BBR(24)720, 67MI11000). 

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 ... 

Inertial Confinement. In the inertial approach, the fuel is heated as it is compressed to a very high density, estimated at about I(KK) times that or the normal density of the solid fuel. An intense energy source is focused onto Ihe outer surface of a specially formed spherical pellet. This produces ablation on the outer surface somewhat similar lo the ablation of a rocket as it is exposed to extremely high temperatures. The energy also causes an implosion (an inward bursting) of the deuterium-tritium fuel mixture in the inneT portion of Ihe pellet. The compression process heats the fuel to ignition temperature and also contributes to the quantity of fuel that can be burned. Inasmuch as the compressed fuel is restrained by its own inertia, the fuel hums before it can fly apart. This is a time span of a billionth of a second or less. ... 

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). 

---