Resources of uranium

Current known, recoverable world resources of uranium are approximately 3.1 million tons, estimated to be sufficient for about 50 years at current levels of consumption. A doubling of price from present levels is projected to create a 10-fold increase in these resources. Moving from current nuclear power technology to breeder reactors is estimated to increase uranium utilization another 60-fold (World Nuclear Association, 2002). Breeder reactors, however, would aggravate some of the issues now associated with the nuclear industry, including those surrounding safety and nuclear proliferation, while possibly reducing the waste disposal problem. 

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. 

Occurrence Pitchblende (essentially U02), a variety of uraninite, coffinite (USi04) and carnotite (Colorado, New Mexico, France, Zaire, Canada, South Africa, Australia, the former U.S.S.R.). U.S. resources of uranium oxide in the 1970s were estimated at 150,000-175,000 tons there is about the same amount in Canada. 

Survey on resources of uranium (1997). The resources (in units of 1,0001) are given separately for well-known and less well-known sites (assured resources/additional estimates] and for different estimated prices of mining ( /per kg of uranium) (NEA 1997)... 

The prospecting of uranium mines is facilitated by the radioactivity of uranium and its daughter products. Uranium deposits are usually judged by their size and by the price it costs to extract a kilogram of uranium. A survey of the worldwide resources of uranium is given in O Table 57.13. 

Measured resources of uranium, the amount known to be economically recoverable from ore bodies, are naturally relative to costs and prices. They are also dependent on the intensity of past exploration effort and are basically a statement about what is known rather than what is present in the earth s crust. 

Current usage is about 65,000 tU/year, so the world s present measured resources of uranium (3.5 Mt) and used only in conventional reactors are enough to last for about 55 years. This represents a higher level of assured resources than is normal for most minerals. 

Surficial deposits comprise about 4% of world uranium resources, and such deposits represent 5% of Australia s total reserves and resources of uranium. They formed where uranium-rich granites were deeply weathered in a semi-arid to arid climate. The Yeelirrie deposit in Western Australia is by far the world s largest surficial deposit. 

Recently, the importance of uranium as a fuel of the nuclear power generation increases with increasing demand of energy, but there is no resource of uranium in Japan. 

The black shale of the Chattanooga Formation in Tennessee is an example of a large low-grade resource of uranium. The mineralized portion of this Devonian. shale occupies. several counties, but mineralized horizons tens of metres thick average only about 0.0. % U,0,(. For the mo.st part, rocks of this type are not of economic importance, unless political considerations dictate otherwise. 

Uranium, relatively abundant in the earth s crust, being present on average at a concentration of 4ppm, is also present in sea water at concentrations of the order of 0.003 ppm. Enormous resources of uranium are therefore available, ocean waters containing an amount equal to some thousand million tons. The effective available uranium resources are, however, estimated on the basis of deposits that contain higher concentrations from which uranium can be extracted at various costs, though not more than 130/kg. On this basis the reasonably assured and additional estimated uranium resources are shown in... 

Uranium resources were originally expected to be rapidly depleted in a growing economy. There were, however, ample suppHes of uranium as of... 

Phosphorite Deposits. Sedimentary phosphorites contain low concentrations of uranium in fine-grained apatite. Uranium of this type is considered an unconventional resource. Significant examples of these uranium ore types include the U.S. deposits in Elorida, where uranium is recovered as a by-product, and the large deposits in North African and Middle Eastern countries (16). 

Domestic. Estimates of U.S. uranium resources for reasonably assured resources, estimated additional resources, and speculative resources at costs of 80, 130, and 260/kg of uranium are given in Table 1 (18). These estimates include only conventional uranium resources, which principally include sandstone deposits of the Colorado Plateaus, the Wyoming basins, and the Gulf Coastal Plain of Texas. Marine phosphorite deposits in central Elorida, the western United States, and other areas contain low grade uranium having 30—150 ppm U that can be recovered as a by-product from wet-process phosphoric acid. Because of relatively low uranium prices, on the order of 20.67/kg U (19), in situ leach and by-product plants accounted for 76% of total uranium production in 1992 (20). 

Estimates of speculative lesouices (SR) at 130/kg uianium and those having an unassigned cost range are provided ia Table 4 (23). These resources, which total about 11.28 x 10 t, would be ia addition to the reasonably assured and estimated additional resources. Estimates of uranium resources from unconventional and by-product sources are presented ia Table 5 (24). These resources total about 7 x 10 t for phosphates, 0.013 x 10 t for nonferrous ores, 0.016 x 10 t for carbonates, and 0.014 x 10 t for lignites. These would be ia addition to the reasonably assured resources, estimated additional resources, and the speculative resources (24). 

Once all technical and pohtical problems are resolved, reactor-grade uranium produced from HEU warhead material could contribute significantly to meeting the anticipated fresh uranium production shortfall. This source, however, is not expected to have a significant impact until the year 2000 or later. The discovery of new low cost resources is not expected to make a significant contribution to production until after the year 2005 because of the very low level of uranium exploration and the relatively long lead times required to develop new production centers (29). 

Resource estimates are divided into separate categories reflecting different levels of confidence in the quantities reported, and further separated into categories based on the cost of production. A listing of uranium resources by country is given in Table 3. 

Table 1.18 Major uranium resources of the world numbered in sequence on the basis of their geological setting and arranged according to their approximate economic significance.

Depending upon lithologic and structural relationship with host rocks, mineralogy, attendant alteration, paragenesis and spatial and temporal constraints, the uranium resources of the world can be assigned to the 15 main categories of uranium ore deposits. They have been shown numerically numbered in sequence in the order of their approximate economic significance in Table 1.18. At present, only 7 can be said to be economically important (see Table 1.19) and these account for more than 95% of the world resources of ura-... 

Commercial-scale application of solvents coming under the category of neutral reagents is largely found as applied to the nuclear industry materials, as in example, for the separation and refining of uranium, plutonium, thorium, zirconium, and niobium. A process flowsheet for extracting niobium and tantalum from various resources is shown in Figure 5.23. It will... 

Ifone assumes resources of 20 million tonnes of uranium and a requirement of200 tonnes/GWyr, affordable resources would suffice for about 100,000 gigawatt-years of light water reactor operation (Bodansky, 1996, Sec. 7.5). 

Nuclear fuel cycle, 77 545-547 safety principles and, 17 546-547 Nuclear fuel reprocessing, 10 789-790 Nuclear fuel reserves, 17 518-530 alternative sources of, 17 527 economic aspects of, 17 526-527 toxicology of uranium, 17 528-529 uranium mineral resources, 17 518-521, 522-525... 

Reasonably assured resources below 80 per kg amount to 2.5 million tonnes of uranium, while RAR resources below 130 per kg amount to around 3.2 million tonnes. (This equals 1230 PJ and 1585 PJ, respectively, assuming that 1 tonne of uranium yields around 0.5 PJ (BGR, 2007).) IR below 80 per kg amount to roughly 1.1 million tonnes and below 130 per kg to approximately 1.4 million tonnes. Total RAR and IR sum up to almost 4.6 million tonnes (2280 EJ). Total undiscovered resources are estimated at 7.5 million tonnes. On top of these resources comes uranium from sources such as energy companies stocks, nuclear arms uranium, etc. 

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