A FRESH LOOK AT NUCLEAR POWERFrois and B. Richter
Fossil fuels, coal, oil and gas, currently meet more than 85% of world energy needs and will continue to dominate for some time. There is no longer any doubt that the increase in atmospheric CO2 is due to our growing use of these fuels without any containment of the CO2 waste. The latest report of the Intergovernmental Panel on Climate Change (IPCC) predicts that the effect of a continuation of this increase in CO2 on the earth’s climate will be significant and often damaging, with rising sea levels, more storms, floods and droughts, the destruction of precious habitats.
Large quantities of additional energy will be needed to fuel economic growth, especially in developing countries with large populations like China, India and Brazil. Currently, some two billion people have no access whatsoever to commercial energy; many more are quite poor by western standards and all will need more energy in the future. If recent trends in energy use continue, as most economic analysts expect, then worldwide demand will grow by about 50% by 2020 and will double by 2050 [1?3]. The growth will be even larger for electricity since, more than any other form of energy, electricity is an essential ingredient of economic development. Yet this growth with the present mix of fuels can only lead to more ecological problems.
Providing more energy economically while limiting the use of fossil fuels is difficult. There is no simple solution. All available options must be considered with an open mind.
Conservation and improved energy efficiency in the most effective options for the new few decades, but these will not be enough on their own. The rate of improvement in efficiency over the last few decades has been smaller than the rate of growth in economic activity, so that energy demand has continued to rise. For the developing world, whose population is fast growing and starts from a small economic base, economic growth is faster and, in the normal course of events, energy use will actually grow faster still for some time to come. The world as a whole, therefore, needs to develop carbon-free energy sources.
Nuclear fission is one of the few large-scale carbon-free energy sources and currently provides 7% of global primary energy (17% of electricity) without any CO2 waste. Its costs are now well known and are unaffected by increases in oil and gas prices. It supplies 35% of the electricity generated in Europe, i.e., 75% of its CO2- free power.
The new ‘renewable’ sources of energy, solar power, wind power, biomass etc., are also carbon free and there is a widespread hope that they will supply higher and higher percentages of our energy mix, but it will not happen easily. This is not because of insufficient R&D. Solar photovoltaïcs, for instance, have benefited from large R&D investments because of their usefulness in space applications. Similarly, tens of thousands of wind generators have been built worldwide. The problem is the cost of the energy and resistance to deploying these low intensity sources, which inevitably impact significantly on the local environment. In 1980, 10% of the Swedish electricity in the year 2000 was foreseen to come from wind power. The correct number in 2000 was 3%.
Hydropower is cost effective, but potential sites are limited and often precious for other reasons so that its growth is also constrained. The OECD expects its contribution to primary energy to fall from 3% today to 2% by 2020 . Renewable energies will not, at least for the foreseeable future, provide for the increased energy need.
In the longer term, from 2050 on, nuclear fusion may prove a very attractive contributor, and R&D on it should be actively pursued. However, the next necessary step in fusion R&D, the demonstration of a self-sustained burning plasma, will take 10 to 15 years and the demonstration of a prototype power plant 15 or more years beyond that. Fusion power cannot begin deployment until 2050 at the earliest.
Well proven and most popular at present is the increased use of natural gas. Because of the so-called “dash to gas,” the OECD expects it to supply a larger share of the larger energy demand expected in the future (26% predicted for 2020; up from 22% at present). Although it is a fossil fuel and does produce CO2 wastes, it is much cleaner than oil or coal and can be used more efficiently in many applications. It is currently cheap, but there is concern that it will not remain so as demand grows and increasingly high-cost supplies must be brought into use.
A second option not yet proven building on our long experience with fossil fuels is to use more of the cheaper, dirtier fossil fuels, coal in particular, and to collect the CO2 waste and dispose of it in the earth or in the oceans, a process usually called sequestration. This technology may not be too difficult, although the overall energy efficiency will inevitably be much less and the cost much higher than for ‘simple’ fossil fuel combustion. The long-term safety of the sequestered CO2 needs to be demonstrated. The difficulties, the costs and risks of this technique are not well known and will need to be carefully evaluated.
OECD predicts not only that the simple use of fossil fuels will supply almost all the increased energy use to 2020, but also that nuclear fission, which releases no CO2 into the atmosphere and is technically easy to deploy on a larger scale, will actually decline, from 17% of electricity generation in 1995 to 9% in 2020 . It must be sensible to look again at why this is so, and consider what measures could reverse the trend.
The large-scale ordering of nuclear power stations which occurred in the two decades up to 1985 has been much reduced since then because, in 1986:
· The accident at Chernobyl raised around the world the fear that nuclear power was not safe enough to use and made the licensing process much more difficult and uncertain.
Fully amortized, operating nuclear plants remain very competitive and have built a good safety record since, so that even countries which had decided to abandon nuclear power have not closed these. Indeed, in many cases life extension is being pursued, but orders for new plants have dried up; hence the OECD prediction.
If gas prices were to remain at their former low levels, and no CO2 controls required, nuclear power would continue to have a hard time to compete in deregulated markets with up?to?date combined?cycle gas turbines. But recent price increases have demonstrated that such long? term price stability of oil and gas is unlikely and that prices will probably increase as demand continues to grow.
It should be emphasized that the cost of nuclear power does include its “externalities,” including the cost of disposal of the radioactive wastes it generates.
In contrast, the use of hydrocarbon fuels does not include any charge for disposing of CO2. For example, the cost of gas power does not yet incorporate the cost of CO2 sequestration. Factoring in these costs would significantly improve the relative competitiveness of both nuclear and renewable energy sources.
It seems likely that burning gas will become more expensive. Conventional nuclear power will then become a competitive alternative for large?scale electricity generation and society will wish to reconsider its other concerns about nuclear power.
No energy source is free from disadvantages. The three major concerns about nuclear power are
· the difficulties to manage radioactive wastes over extremely long periods of time
· the risks of proliferation of nuclear weapons.
Chernobyl demonstrated the devastating consequences of a very large accident in a large nuclear reactor. It was well known in the 1960’s that reactors of the Chernobyl type did not meet sufficiently high safety standards. Western reactor types are much lower risk and cannot operate in the mode that destroyed Chernobyl. Since Chernobyl, 5000 reactor years of experience has been accumulated worldwide without any serious accident. Modern reactor designs do take account of a possible core meltdown, no matter how low the probability of such an event, and implement means to mitigate its potential consequences.
Nuclear power does produce radioactive wastes. However, the short-lived wastes from operations are already disposed of safely in many countries. Comprehensive research for decades has led to a common view among international experts that the “knowledge and technology exist” for safe waste management, ready to be used by society. The final disposal of the long-lived waste is not yet industrially implemented, but demonstrations are under way in several countries.
In the longer term, research is under way to develop systems (reactors and fuel cycles) that are able to maximize the use of uranium and reduce still further the volumes and toxicity of long lived waste products.
The possibility for any nation state to make nuclear weapons has existed ever since the discovery of fission. Whether or not the use of commercial nuclear power increases this risk is debatable. On the one hand, it can shorten the time necessary to acquire fissile materials. On the other hand, it facilitates strong international safeguards and control of fissile materials that greatly increase the probability of detecting clandestine activities and allow political pressure to be applied before it is too late. Also, it contributes to a secure and stable global supply of energy, essential to prevent the tensions that encourage proliferation.
Today, overall, only 4% of the initial quantity of fuel is consumed in a reactor, i.e., less than 1% of the quantity of natural uranium needed for the production of enriched uranium. The spent fuels removed from the reactors contain 95% of uranium, 1% of plutonium and 4% of fission products. Only fission products constitute waste. Uranium and plutonium can be re-used to produce energy. With the dual aim of economizing natural resources and optimizing waste management, some countries, such as France, process the spent fuel to separate the energy-yielding materials from the waste. The recycled uranium is stored with the prospect of its use at a later date in fast breeder reactors, and the plutonium is recycled in today’s reactors in the form of MOX fuel, a mix of uranium and plutonium. If the use of nuclear energy is to be greatly expanded to reduce man-made greenhouse gases, some such system will be needed.
To continue the development of nuclear energy, we must provide effective and acceptable technical solutions for the long-term management of the radioactive wastes produced by current reactors; solutions do exist and could be gradually implemented.  Geological disposal in appropriate material is workable. However, not all countries have good sites, and in an expanded nuclear scenario an international solution is needed.
Studies are underway on multiple recycling of plutonium in power reactors, thus destroying it and leaving the fission fragments and minor actinides for geological storage.
Also under study are transmutation systems which convert the long-lived component of spent fuel to a form only requiring isolation for on the order of hundreds of years to a thousand years — a time span of already existing man-made structures.
Preparation for the future sustainable development of nuclear energy will involve a new generation of nuclear power generation systems, in an inclusive approach covering all the aspects of the reactor and fuel cycle. The “Generation IV” international initiative (Europe, United States, Japan, Russia, etc.), aims to develop, for deployment around 2030, new types of nuclear reactors which are simpler, completely free from core?meltdown, and competitive with the best fossil?fired plants, as well as fuel cycles more resistant to proliferation. Comprehensive assessment studies have already demonstrated that these objectives are achievable.
Globally, the processing of spent fuels, the consumption of the plutonium in light water reactors, and the transmutation of long-life radiotoxic wastes (minor actinides) in the new generation reactors, could reduce the long-life radiotoxicity of the waste by a factor of 100, leaving a residual radioactivity that would then be comparable to that of the initial natural uranium after several hundred years.
The development, in an extended international perspective, of a new generation of nuclear power production systems offers attractive opportunities for meeting the challenges for the development of carbon-free sustainable energy sources. The characteristics of this technology are promising (cost, safety, environmental protection) and offer the possibility of implementing several configurations, suited to the economic and technical context in question, thereby enabling a gradual deployment on the international market.
Providing the energy needed to satisfy the ambitions of a growing world population for a decent living standard will not be easy. Doing it without greatly increasing the already worrying risks of climate change will be exceptionally difficult.
Nuclear power is available now and will remain an option for the future as long as there is no proven alternative with the required potential. No other energy source is available for large- scale production at the multi-gigawatt scale.
To keep the nuclear option open, research is of paramount importance to develop improved designs, maintain and renew expertise, whilst continuing to build competence in operation and decommissioning of the present generation of reactors. (For complete report with graphics go to http://bifrost.physik.tu-berlin.de/~iupap/ and click on presentations)
 European Commission Scientific and Technical Committee, EUR 19786 EN
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