6.6.1 Uranium resources — long-term prospects

An orebody is, by definition, an occurrence of mineralisation from which the metal or mineral is economically recoverable. It is therefore relative to both costs of extraction and market prices. At present neither the oceans nor any granites are uranium orebodies, and they are unlikely to become so even if prices were to rise substantially (Table 6.2).

Measured resources of uranium, the amount known to be economically recoverable from orebodies, are thus also relative to costs and prices. They are also very dependent on the intensity of past exploration effort, and are basically a statement about what is known rather than what is there in the Earth’s crust — epistemology rather than geology.

From time to time concerns are raised that the known resources might be insufficient when judged as a multiple of present rate of use. But this is the Limits to Growth fallacy, a major intellectual blunder recycled from the 1970s, which misunderstands the meaning of resource data, taking no account of the very limited nature of the knowledge we have at any time of what is actually in the Earth’s crust. Our knowledge of geology is such that we can be confident that identified resources of metal minerals are a fraction of what is there.

Table 6.3 and Fig. 6.3 show the current known recoverable resources of uranium by country. Uranium is not a rare element and occurs in potentially recoverable concentrations in many types of geological settings. As with other minerals, investment in geological exploration generally results in increased known resources. Over 2005 and 2006 exploration effort resulted in the world’s known uranium resources increasing by 15% in those two years.

The most common uranium product from mines is U3O8, which contains about 85% uranium. Table 6.3 refers to pure uranium, but the production figures may be expressed in terms of U3O8 by multiplying by 1.1793.

Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/09, from OECD NEA & IAEA, Uranium 2009: Resources, Production and Demand (‘Red Book’).

The current global demand for uranium is about 68 500 tU/yr (Fig. 6.2). The vast majority is consumed by the power sector with a small amount also being used for medical and research purposes, and some for naval propulsion. In total this mined uranium accounts for 78% of annual nuclear power station requirements. The remainder is made up from secondary supplies as outlined.

6.3 Known uranium resources (000 tU). IAEA & NEA Red Book 2009, resources to $130/kg U.

Thus the world’s present measured resources of uranium (5.4 Mt) in the cost category a bit above present spot prices and used only in conventional reactors, are enough to last about 80 years. This represents a higher level of assured resources than is normal for most minerals. Further exploration and higher prices will certainly, on the basis of present geological knowledge, yield further resources as present ones are used up.

In the third uranium exploration cycle from 2003 to the end of 2009 about US$ 5.75 billion was spent on uranium exploration and deposit delineation in over 600 projects. In this period over 400 new junior companies were formed or changed their orientation to raise over US$ 2 billion for uranium exploration. About 60% of this was spent on better defining and quantifying previously known deposits. All this was in response to the increased uranium price in the market.

The price of a mineral commodity also directly determines the amount of known resources that are economically extractable. On the basis of analogies with other metal minerals, a doubling of price from present levels could be expected to create about a tenfold increase in measured economic resources, over time, due both to increased exploration and the reclassification of resources regarding what is economically recoverable. Thus, any predictions of the future availability of any mineral, including uranium, which are based on current cost and price data and current geological knowledge are likely to be extremely conservative.

This is in fact suggested in the IAEA-NEA figures if those covering estimates of all conventional resources are considered — another 5.5 Mt (beyond the 5.4 Mt known economic resources), which takes us to 160 years’ supply at today’s rate of consumption. This still ignores the technological factor mentioned below. It also omits unconventional resources such as phosphate/phosphorite deposits (up to 22 Mt U recoverable as by-product) and seawater (up to 4000 Mt), though this would be uneconomic to extract in the foreseeable future.

It is clear from Fig. 6.4 that known uranium resources have increased almost threefold since 1975, in line with expenditure on uranium exploration. (The decrease in the decade 1983-1993 was due to some countries tightening their criteria for reporting. If this were carried back two decades, the lines would fit even more closely. The change from 2007 to 2009 is due to reclassifying resources into higher-cost categories.) Increased exploration expenditure in the future is likely to result in a corresponding increase in known resources, even as inflation increases costs of recovery and hence tends to decrease the figures in each cost category.

About 20% of US uranium came from central Florida’s phosphate deposits to the mid 1990s, as a by-product, but it then became uneconomic. With higher uranium prices today the Florida resource is being examined again, as is another lower-grade one in Morocco.

A technological factor also bears upon consideration of future uranium supplies. Widespread use of the fast breeder reactor could increase the utilisation of uranium

50-fold or more. This type of reactor can be started up on plutonium derived from conventional reactors and operated in closed circuit with its reprocessing plant. Such a reactor, supplied with natural or depleted uranium for its ‘fertile blanket’, can be operated so that each tonne of ore yields 60 times more energy than in a conventional reactor. Furthermore, the 1.5 million tonnes of depleted uranium left over from enrichment plants around the world can be used a fuel for fast reactors.

There is no reason to anticipate any shortage of uranium that will prevent conventional nuclear power from playing an expanding role in providing the world’s energy needs for decades or even centuries to come. This does not even take into account improvements in nuclear power technology, which could effectively increase the available resource dramatically.