Thorium resources

Heretofore, most of the world s thorium has come from monazite in beach sands where coproduction of rare earths, titanium, and zirconium has defrayed much of the cost of 

Since 1975, renewed interest in thorium as source material for production of has led to extensive prospecting for thorium, discovery of numerous potentially commercial deposits and substantial increase in U.S. resource estimates over those listed in Table 6.13. 

Until recently, most U.S. thorium production has been as a by-product of monazite processing from placer deposits in Florida, Georgia, and South Carolina. Some bastnaesite has been mined at Mountain Pass, San Bernardino, California. 

Geological Survey was scheduled to publish a revised study of U.S. thorium resources in August 1979. Partial results of this study, which cover most of these resources but do not include the beach placers of Florida, Georgia, and the Carolinas, were presented orally by Staatz [S5] of the U.S. Geological Survey in 1978. Table 6.14 lists the types of deposit, the principal districts in which potentially economic thorium-bearing deposits have been found, the principal thorium minerals, and estimates of thorium reserves and resources. Thorium from the vein deposits, the first type, could be produced for less than 30/lb. Thorium is the principal salable product in these deposits. Thorium could be coproduced with other elements from disseminated deposits, massive carbonatites, and placers the amount of thorium that might be produced from them, and its cost, depends on the marketability of the other minerals that occur with the thorium. 

Mineral Nominal composition Examples of where found 

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Research and development activities for thorium fuel cycles have been conducted in Germany, the USA, India, Japan, Russia and the UK during the last 30 years at a much smaller scale than uranium and uranium-plutonium cycles. Nowadays, India, in particular, has made the utilisation of thorium a major goal in its nuclear power programme, as it has ambitious nuclear expansion plans and significant indigenous thorium resources. 

Current estimates of the available reserves and further resources of uranium and thorium, and their global distribution, are shown in Figs. 5.44-5.50. The uraruum proven reserves indicated in Fig. 5.44 can be extracted at costs below 130 US /t, as can the probable additional reserves indicated in Fig. 5.45. Figure 5.46 shows new and unconventional resources that may later become reserves. They are inferred on the basis of geological modelling or other indirect information (OECD and IAEA, 1993 World Energy Council, 1995). The thorium resource estimates are from the US Geological Survey (Hedrick, 1998) and are similarly divided into reserves (Eig. 5.47), additional reserves (Fig. 5.48) and more speculative resources (Fig. 5.49). The thorium situation is less well explored than that of uranium the reserves cannot be said to be "economical", as they are presently mined for other purposes (rare earth metals), and thorium is only a byproduct with currently very limited areas of use. The "speculative" Th-resources may well have a similar status to some of the additional U-reserves. 

Figure 5.49. New and unconventional thorium resources given as kg of thorium oxide per m averaged over each country (with use of Hedrick, 1998 GIS layout Sorensen, 1999).

The thorium requirement per country may be compared with the assumed production in each country, shown in Fig. 5.59. It is determined by assuming that the world production of thorium matches the world requirements, and that each country produces in proportion to its total thorium resources, as estimated in Fig. 5.51. 

B2. Battelle Pacific Northwest Laboratories Assessment of Uranium and Thorium Resources in the United States and the Effect of Policy Alternatives, Richland, Wash., Dec. 1974. 

Table 6.13 gives the thorium resources of the non-Commimist world as estimated by the Organization for Economic Cooperation and Development [01] in December 1977. The definitions of the two resource categories are the same as for Table 5.17. The production cost of these thorium resources was not stated in [01], but was probably 15/lb ThOj, from similar statistics cited by Nininger and Bowie [N3].

Table 6.14 Principal U.S. thorium resources, metric tons thorium ... 

Staatz, M. H. Update on Thorium Resources, Paper presented at Department of Energy Symposium, Grand Junction, Colorado, Oct. 1978. 

Data from various sources, inpluding AEC press release, Fossil Fuel and Uranium and Thorium Resources. ... 

Brazilian uranium resources are presently estimated in 300,000 metric tons and the estimate on the thorium resources is of the order of one million metric tons. The country has presently one reactor (PWR/626 MWe) in operation and a second one (PWR/1300 MWe) has recently received authorization for completion, which is planned for 1999. A third reactor (PWR/1300 MWe), originally planned to be constructed in the same site as the other two is still awaiting for a government decision. 

The bred is subsequently put into the fluoride melt in order to undergo fission. The proposed system has a number of additional advantages. (1) It is estimated that about 10% of the electricity produced from the reactor is sufficient to operate the accelerator. (2) The available thorium resources are larger than those of uranium and since thorium would be 100% burned it would provide mankind with energy for centuries. (3) Mining of thorium is easier and ecologically less problematic than mining of uranium. (4) The fission of thorium produces considerably less of the problematic transuranium elements (Np, Pu, Am, etc.). 

Nuclear power plants, mostly of the pressurized heavy water(PHWR) type, are being built in the country to meet the increasing demand for energy. The PHWRs also form the first stage of nuclear power plant types to utilise the existing uranium reserves in such a manner as to lead to the full exploitation of the vast thorium resources available in the country. 

Thorium resources on earth are non-localized but geochemically three times more prevalent than the uranium ones. Thorium resources have already been confirmed at about 2 million tons and estimated at about 4 million tons as shown in Table XXX-4. 

TABLE XXX-4. ESTIMATED WORLD THORIUM RESOURCES [XXX-21] (thousands of tons)... 

Thorium resources necessary for a 1000 TW(e)-year production globally foreseen by the THORIMS-NES for the 21st century, Fig. XXX-3, will be only about 2 million tons (assuming one-third of them will fission), which is comparable to about 1.5 million tons of uranium already extracted from the earth. Thorium could be obtained from the heavy sand of beaches with relatively little pollution. 

ENEA. World uranium and thorium resources. February 1968. 

In summary, if a substantial majority of actinides are recycled (which will be necessary for us to tap the majority of the potential energy of uranium and thorium resources), then the waste stream from fission power will consist of a very small volume of fission products along with a small fraction of lost actinides. This waste can be readily immobilized in an insoluble material, such as borosilicate glass. The efficiency of actinide-separation technology will determine whether this waste inventory will decay to ore-level radiotoxicity in hundreds of years or thousands of years. Thus, improvements in separation technology may have a significant impact on the waste-isolation time and on public acceptance of fission power. 

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