Production of Tritium

Over the years, a variety of fuel types were employed. Originally, natural uranium slugs canned in aluminum were the source of plutonium, while lithium—aluminum alloy target rods provided control and a source of tritium. Later, to permit increased production of tritium, reactivity was recovered by the use of enriched uranium fuel, ranging from 5—93%. 

Nuclear Reactions. The primary reaction for the production of tritium is... 

The production of tritium-labelled organic compounds was enormously facilitated by K. E. Wilz-bach s discovery in 1956 that tritium could be introduced merely by storing a compound under tritium gas for a few days or weeks the radiation induces exchange reactions between the hydrogen atoms in the compound and the tritium gas. The excess of gas is recovered for further use and the tritiated compound is purified chro-matographically. Another widely used method of... 

He is present in natural gases with a concentration of MO-7 of that of 4He and 1(T6 of the helium in the atmosphere. The separation is very expensive. Hence 3He is instead obtained as by-product of tritium production in nuclear reactors. Tritium in fact produces, by beta decay (the half life is 12.26 years), 3He the separation of 3He is obtained through a diffusion process. 

A number of decay products may be of interest ultimately as a basis of dating groundwater. At present, however, the accumulation of inert gases appears to offer the most significant possibilities for dating [19,36,58-60]. Some candidate gases are given in Table 3. Of those listed, 4He will probably be the most useful because of its relatively rapid rate of production. As already mentioned, because it is the decay product of tritium, the other... 

Separation of 6Li from natural abundance (7.4%) feed to synthesize 6LiD (an important component of the fuel used in hydrogen fusion weapons (hydrogen bombs)). This, because the (n,T) cross section for 6Li is much larger than that of 7Li, so production of tritium is much enhanced in the triggering explosion. 

The tritium atoms are oxidized to water and become mixed with precipitation and so enter the groundwater. The natural production of tritium introduces about 5 TU to precipitation and surface water. 

The average global production of tritium is —2,500 atom m s (Solomon and Cook, 2000). The deposition rate of the tritium varies with latitude, but it is also mixed with the bulk of precipitation originating from the ocean (which has a very low tritium content), and thus the average tritium content of precipitation tends to vary inversely with annual precipitation. Natural tritium in precipitation varies from —1 TU in oceanic high-precipitation regions to as high as 10 TU in arid inland areas. 

Reactor fuel for the production of plutonium and target manufacture for the production of tritium involves the use of material and machinery common to other manufacturing industries with the exception of uranium and possibly enriched lithium. Aqueous waste from such operations may find its way to surface water systems and is the primary source for short- and long-range detection. 

An interesting application of catalytic membrane reactors [14,136] relates to the production of tritium which together with deuterium will be the fuel for the fusion reactors of the future. Tritium is produced by mearts of a nuclear reaction between neutrons and lithium atoms in a breeder reactor. The tritium thus produced must be further purified to reach the purity levels that are required in the fusion reactor. For the extraction and purification process Basile and... 

In contrast to the investigations with calcium where Ca, which is not the preferable calcium isotope for application purposes, is enriched in the chloroform phase (see Chap. 4.2.2), Li which is of importance for the production of tritium is enriched in that phase. Certainly, corresponding to the disadvantageous distribution coefficient (see Table 10) a small amount of enriched Li is only obtainable within one equilibrium stage. Therefore, a cascade experiment as described in Chap. 2.5.2 must be applied. 

The investigation of isotopic separations in systems with cyclic polyethers has been carried out up to now for the elements lithium, calcium and sodium, in particular. Among these elements, the enrichment of Li is of essential importance for the production of tritium and that of the heavy calcium isotopes for medical labeling experiments. An enrichment aspect does not exist for the monoisotopic element sodium. Investigations with the radioactive nuclides Na and Na are obviously of interest for fundamental investigations because these isotopes can be easily and precisely measured by their y-activity. Except for uranium, most of the investigations on other chemical exchange systems with metal ions are also based on measurements with lithium and calcium, respectively. 

It is feasible to breed more tritium in a lithium cooled reactor than is used in the reaction. The excess tritium can be used to start other reactors or in a reactor using some coolant other than lithium that prevents it from breeding its own tritium. Nature has been kind with the properties of lithium. It is an excellent choice for transferring heat from the reactor and it is the raw material needed for the continual production of more fuel. Both these functions can be provided by the use of liquid lithium as the blanket material. The isotopic composition of the lithium may be adjusted to provide the proper balance of lithium 6 and lithium 7 to optimum heat transfer and production of tritium. The lithium can also be diluted with metallic sodium or potassium to aid in adjusting the tritium production rate. 

Numerous reactions are available for the artificial production of tritium and it is now made on a large scale by neutron irradiation of enriched Li in a nuclear reactor ... 

The lithium is in the form of an alloy with magnesium or aluminium which retains much of the tritium until it is released by treatment with acid. Alternatively the tritium can be produced by neutron irradiation of enriched LiF at 450° in a vacuum and then recovered from the gaseous products by diffusion through a palladium barrier. As a result of the massive production of tritium for thermonuclear devices and research into energy production by fusion reactions, tritium is available cheaply on the megacurie scale for peaceful purposes. The most convenient way of storing the gas is to react it with finely divided uranium... 

The fuel discharged yearly from the 1000-MWe HTGR of Fig. 3.33 contains 90.5 Mg of graphite [P3]. The yearly production of tritium from neutron activation of lithium impurities is then estimated to be... 

The resulting steady-state rate of production of tritium in the coolant from He(n, p) is 124 Ci/year. 

In the CANDU heavy-water reactor the dominant source of tritium is the deuterium activation reaction of Eq. (8.53). The data given in Prob. 3.3 for the Douglas Point Nuclear Power Station provide a basis for estimating the rate of production of tritium in the heavy-water moderator and coolant ... 

Andrews JN, Kay RLF (1982) Natural production of tritium in permeable rocks. Nature 298 361-363... 

This natural inventory was dwarfed by the production of tritium by the atmospheric testing of nuclear fusion weapons during the 1950s and early 1960s. During this period, several hundred kilograms of tritium were released, largely late in the test series, and primarily in the Northern Hemisphere. The... 

The excitation function for the production of tritium by the reaction JA [dt) was followed by Macklin and Banta from 0.4 to 4.0 MeV. The tritium was recovered and estimated by counting beta disintegrations in a proportional counter. 

The production of tritium will depend upon the final choice of salts. If the AHTR uses nonlithium molten salts, the total tritium production will be less than for gas-cooled reactors and there will be a much lower tritium level in the coolant. If molten-salts with LiF are used, the tritium production will be significantly higher than for helium-cooled reactors but similar tothat for the Canadian Deuterium... 

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