Uranium: Sustaining the Global Nuclear Renaissance
Uranium, a naturally occurring and abundant element, possesses characteristics that account for the unique virtues of nuclear power:
- Emissions-free Energy. Because the splitting of the uranium atom releases energy without the combustion of carbon, there is virtually no production of greenhouse gases - which is the major waste product from fossil fuel.
- Manageability of Waste. The small amount of uranium required to produce a huge amount of nuclear energy leaves a correspondingly small amount of solid waste, which can be safely contained and managed without environmental harm.
- Energy Independence and Security. Because nuclear fuel supplies are relatively inexpensive and highly energy-intensive (and thus small in volume), they can readily be stockpiled, affording a major buffer against energy insecurity.
- Power Price Stability. Because uranium fuel represents a small proportion of the generating costs of nuclear power, relative price stability for power is assured regardless of uranium price fluctuations. Meanwhile, as this paper discusses, such fluctuations serve the useful purpose of providing an adequate uranium supply.
At a time when a widespread recognition of these benefits has pointed energy planners toward a major worldwide expansion of nuclear power, it is sometimes asserted that limited uranium resources will seriously constrain any nuclear renaissance. This WNA Position Paper responds to that concern.
There is every reason to expect that the world supply of uranium, as of other metals, is sustainable, with adequate known resources being continuously replenished at least as fast as they are being used and at costs affordable to consumers. Speculation to the contrary represents a misunderstanding of the nature of mineral resource estimates and reflects a short-term perspective that overlooks continuing advances in knowledge and technology and the dynamic economic processes that drive markets.
Concerns about limitations on the Earth's resources go back more than a century. Although they appear intuitive and logical on the basis that mined mineral resources are clearly finite and physically not renewable, in most cases careful analysis shows that limits to the supply of resources are so far away that concerns have little practical meaning.
There are, however, examples such as oil, where prices and sophisticated projections may now be indicating that proven reserves are indeed beginning to run out. Concerns about resource depletion therefore deserve careful examination.
Characteristically, predictions of scarcity based on published mineral reserve figures do not stand up to close scrutiny because they fail to take adequate account of three key "resource-expanding factors":
- Gains in Earth Knowledge and Discovery Capabilities. Not accounting for gains in knowledge of the mineral deposits in the Earth's crust and in technologies used to discover them.
- Gains in Mining Technology. Not allowing for progress in mining and processing technologies used to recover mineral deposits.
- Changes in Mineral Economics. Not taking into account what will be economic over time in light of price changes and technological developments.
To achieve sustainability, the combined effects of mineral exploration and technology development must create known resources at least as fast as they are being used.
Historic data teaches the important lesson that this has regularly occurred, and continues to occur, with most minerals. Reserve margins for metals, stated in terms of multiples of current use, have been continuously replenished or - more often - increased. On average, real prices for metals have tended to fall over time.
It is important to recognise - with any commodity at any time - that one should never expect to see known economic resources of more than a few decades because exploration will only take place if companies are confident of making a financial return. The prospect of return is usually dictated by strong prices flowing from the prospect of imminent undersupply. When this happens, there tends to be a strong surge of exploration effort yielding significant new discoveries.
Geology of Uranium
Uranium's average abundance in the Earth's crust is 2.7 parts-per-million (ppm), which is comparable with other metals such as tin, tungsten and molybdenum. In addition, many common rocks such as granite and shales contain much higher uranium concentrations - of 5 to 25 ppm. Uranium is also present in seawater in trace amounts.
Thus, as a starting point, uranium is not scarce in a geological sense.
Moreover, uranium is easily removed from its host minerals. Economically extractable concentrations of uranium also occur in more than a dozen different deposit types in a wide range of geological formations. This diversity is, for example, far greater than that for oil. It means that uranium discoveries need not be confined to a few geological settings and creates a high probability that known economic resources will be replenished.
Uranium's history as a resource is quite short, with military demand beginning during World War II and serious non-military demand not arriving until the late 1960's.
Today annual requirements to fabricate fuel for current power reactors amount to about 67,000 tonnes of uranium. According to the authoritative "Red Book" produced jointly by the OECD's Nuclear Energy Agency and the UN's International Atomic Energy Agency, the world's present known economic resources of uranium, exploitable at below $80 per kilogram of uranium, are some 3.5 million tonnes. This amount is therefore enough to last for 50 years at today's rate of usage - a figure higher than for many widely used metals.
Current estimates of all expected uranium resources (including those not yet economic or properly quantified) are four times as great, representing 200 years' supply at today's rate of usage.
It cannot be overemphasised that these numbers, though themselves providing a favourable prospect, understate future uranium availability because known resources of most minerals bear little relationship to what is actually in the outer part of the Earth's crust and potentially extractable for use. Known economic resources are an unrealistic indicator of what will actually be available long-term.
At most, they are useful as a guide to what is available for production in an immediate future spanning no more than a few decades.
In the case of current economic resources of uranium, the 50-year quantification is no more than a rear-view mirror perspective on supply. During future consumption of these resources, the dynamics of supply and demand will produce price signals that will inevitably trigger effects involving all three of the "resource-expanding factors" cited above. This is already evident in today's uranium market.
As a commodity, uranium has a short history because it has no direct use apart from supplying the relatively young industry of nuclear energy production. By all evidence, however, the uranium market is little different from that of other metals in being subject to cycles of exploration, discovery and production.
Thus far, uranium has experienced only one such cycle. After initial discoveries, uranium's history shows declining real prices and then, following a price spike in the late 1970s, a significant exploration boom. But this one cycle offers considerable reassurance in that it met reactor requirements for more than half a century while also providing 3.5 million tonnes of known and defined resources awaiting recovery.
Based on this history, it is clearly premature to talk about long-term uranium scarcity.
Replenishment and Increase of Known Resources
With uranium as with other mineral resources, published figures will continue to evolve as a result of ongoing exploration and analysis.
The dynamic of the market inevitably creates a pattern whereby usage produces price signals that result in exploration; and historically, expenditure on exploration for uranium, as for other metals, has correlated well with discovery and the replenishment of known economic resources.
Of the three "resource-expanding factors" cited above, the first - gains in knowledge of mineral deposits and advances in the technologies of mineral discovery - is highly significant.
A good example involves Canada's main uranium discoveries made in the Athabasca Basin in the 1970s. Then, airborne electromagnetic surveys were effective to only 100 metres depth below the surface. Today such surveys yield useful data ten times as deep - down to a full kilometre.
Equally important is the second "resource expanding factor" - gains in mining technology.
Ten years ago, known uranium resources were only 2.1 million tonnes. The increase to 3.5 million tonnes today is partly attributable to the addition of a few new countries and new discoveries. But the growth in known resources is also a function of applying improved techniques of exploitation to yield an expanded definition of previously known deposits.
In particular, the development of in situ leaching (ISL) techniques now permits low-cost mining of resources previously viewed as economically non-viable.
As to the power of price signals to trigger uranium exploration, there is fresh evidence. With the almost tripling of spot uranium prices since 2003, we see not only increased exploration expenditure by existing major companies but also the re-emergence of junior uranium exploration companies seeking opportunity.
This expanded activity - which can be expected to produce new discoveries and the eventual commissioning of new uranium mines - is occurring even though prices, in real terms, are still substantially below peak levels of the past.
"Secondary Supplies" of Nuclear Fuel
Secondary supplies of uranium - supplies from military and civilian stockpiles - became important in the period after 1985 as excessive commercial inventories were run down and as East-West arms control began to achieve substantial dismantling of nuclear warheads, yielding commercially usable fissile material. Since then, primary uranium production has regularly filled no more than 60% of annual requirements.
This surplus has had the effect of depressing prices and thus delaying the next exploration cycle, as there was little economic incentive to invest in new developments.
Although these secondary supplies will remain an important part of the market for some years to come, they are by definition limited, as their source is previously-mined uranium. As secondary supplies are depleted, primary uranium production will pick up strongly to fill their place.
Additional Sources of Nuclear Fuel
Even without the third factor cited above - "Changes in Mineral Economics" - there is reason for high confidence that adequate and affordable supplies of uranium can be found to fuel the nuclear industry, even at greatly expanded levels of activity, using current technology.
But the third factor - which includes changes in what is economic depending on price, possibilities of substitution, and further advances in nuclear technology - provides added levels of assurance.
Indeed, already well-known nuclear technologies offer a wide range of possibilities for stretching uranium supplies - to a very considerable extent - as market forces render these options economically attractive:
Used nuclear fuel can be reprocessed to recover unburned fissile material. Depending on reactor core management, this increases the efficiency of uranium utilization by up to 30 percent. Today, while accounting for only 3% of world nuclear fuel supply, reprocessing is already occurring on a substantial scale and could well become increasingly attractive as market conditions evolve.
- Increased Enrichment.
Most reactor types require enriched uranium fuel. If uranium becomes relatively more expensive compared with enrichment (through price changes in either), increasing the input of enrichment services to optimise fuel cost can save on uranium use in reactors.
The element thorium, which is four times more abundant in the Earth's crust than uranium, constitutes an additional source of nuclear fuel. Although thorium is not fissile, it is "fertile" - capable of being converted into fissile U-233 - and technologies for making this conversion are already well advanced in some places, notably India.
- Enhanced Reactor Efficiency.
Evolutionary light-water reactor designs, which are all more fuel-efficient than their predecessors, will be the mainstay of nuclear programmes over the next decades.
However, in the period beyond 2030, advanced reactor designs such as those included in current multinational research programmes (called Generation IV and INPRO) represent a further step forward in fuel efficiency.
- Breeder Reactors.
Some advanced reactor designs are fast-neutron types, which can utilise the U-238 component of natural uranium (as well as the 1.2 million tonnes of depleted uranium now stockpiled as a result of enrichment activities).
When such designs are run as "breeder reactors" - with the specific purpose of converting non-fissile U-238 to fissile plutonium - they offer the prospect of multiplying uranium resources 50-fold and thereby extending them far into the future.
The technology is well-proven, with some 300 reactor-years of experience, and breeder reactors are already firmly emplaced in the long-range energy plans of such nations as Russia, Japan and India.
The uranium resource is sustainable, with adequate known resources being continuously replenished at least as fast as they are being used. The essential dynamic is the strength of market forces when the market is constantly evolving through advances in human knowledge and the technologies of exploration, mining, and resource utilisation. Depletion of today's known uranium resources will be more than counterbalanced by replenishment from new discoveries, technical progress and possible substitution.
In addition, a huge increase in efficiency is readily possible through the technological step to fast neutron reactors. This option - unique among mineral resources - offers the nuclear industry a special kind of insurance against future resource shortage.
It may therefore be fairly concluded that uranium supplies will be more than adequate to fuel foreseeable expansions of nuclear power. Indeed, in addition to its other noteworthy virtues, an abundant fuel resource will remain a crucial advantage of nuclear power. The world faces many challenges in achieving a global expansion of nuclear energy to fully realise the technology's clean-energy potential. A limited supply of uranium resources is not among them.
1. Uranium 2003: Resources, Production & Demand, Nuclear Energy Agency (OECD) and International Atomic Energy Agency, 2004. Known as the Red Book, this biennial publication is the "bible" on uranium resource estimates. It provides detailed figures and commentary for all countries with known uranium deposits.
2. Trends in the Nuclear Fuel Cycle, Nuclear Energy Agency (OECD), 2001. Of particular interest is Chapter 3, which discusses nuclear power as a sustainable energy source and describes the likely technical shifts that should lead to uranium resources lasting for many centuries in the future.
3. Uranium: Sustainable Resource or Limit to Growth, Colin MacDonald, paper at the Annual WNA Symposium, 2003. Available at www.wna-symposium.org, this analysis discusses the nature of uranium resource estimates, stressing the dynamic responses to price and other signals that result in exploration and continued renewal of the resource base.
4. Supply of Uranium, WNA Information and Issue Brief, contains an appendix providing examples pointing to the sustainability of uranium in the nuclear fuel cycle.