Global production rate

Element U.S. consumption, million metric tonnes U.S. Global production, Production, million metric million metric tonnes tonnes Reserves, million metric tonnes Years of Reserves at Current Global Production Rate (U.S.) per metric tonne U.S. consumption Global Production Primary Uses... 

Pii (about 2.2 kg), -" Pu (about 1.1 kg) and " Pu (about 0.4 kg) are generated by (n, y) reactions from Pii. Pu is a valuable nuclear fuel and may also be used for production of nuclear weapons. The global production rate of Pu in nuclear power reactors is of the order of 100 tons per year contained in spent fuel elements. Non-proliferation agreements should prevent uncontrolled distribution of Pu. Moreover, Pu is highly toxic. Am and Cm arc generated in smaller amounts in nuclear reactors by (n, /) reactions (about 0.15 kg Am and about 0.07 kg Cm per ton of spent fuel after a burn-up of 35 000 MW d per ton). 

Source mechanisms are the main subject of this section. We describe the production of mineral dust, sea salt, and condensation nuclei, then present estimates of global production rates. 

Table 7-11. Estimates for Global Production Rates (Tg/yr) of Particulate Matter from Natural and Anthropogenic Sources... 

As discussed in 19.10, Pu has been formed in natural uranium reactors at a later stage of the earth s evolution. Many thousands of tons of plutonium has been synthesized in commercial and military reactors the annual global production rate in nuclear power reactors in the year 2000 was 1000 tons/y, contained in the spent fuel elements. The nuclear reactions and chemical separation processes are presented in Chapters 19 and 21. The build-up of heavier elements and isotopes by n-irradiation of Pu in nuclear reactors is illustrated in Figures 16.2 and 16.3. The accumulated amount of higher actinides within the European commimity is many tons for Np, Pu and Am, and himdreds of kg of Cm the amounts in the United States and Russia are of the same magnitude. 

It has been found that the concentrations of Be in the deep-sea sedimentation cores vary mostly due to the changes in sedimentation rates. However, climatic changes and the variation of Earth s magnetic field may also be responsible for the changes of Be contents in sediments. It has been inferred that global production rates of Be have been varied by less than 30% in the past 2.5 Ma when averaged over periods of 10 years (Reddy et al. 1983 Somayajulu 1977 Tanaka and Inoue 1979 Sharma and Somayajulu 1982). 

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