Nuclear Energy for Tomorrow

Luis E. Echávarri, Director-General
OECD Nuclear Energy Agency
Speech to the meetng of G8 Energy Ministers, Detroit, 3 May 2002

 

Nuclear energy already is a mature technology, benefiting from several decades of development and industrial experience. It has the potential for contributing to future sustainable supply of energy services, taking advantage of feedback from past experience and ongoing R&D programmes on advanced systems.

The future of nuclear energy will depend on the evolution of the broad social and economic context and on technology progress and breakthroughs that will be achieved. Reviewing the present status and trends in the field of nuclear energy provides some insights into its future prospects. A rapid survey of recent achievements in technology progress and R&D programmes complements the overall picture of nuclear energy potentials and its likely future. Both past experience and ongoing activities illustrate the benefit of international co-operation and the role of international organisations such as the OECD Nuclear Energy Agency.

Nuclear energy today

Nuclear energy has moved from the discovery of fission to a mature technology commercially deployed in many countries over a relatively short period of time. The first kWh of nuclear electricity was delivered to the grid only some 50 years ago, and today nuclear energy contributes to energy supply in more than 30 countries, including 16 OECD countries. More than 10 000 reactor-years of commercial operation experience, including 8 000 reactor-years in OECD countries, have been accumulated.

By the end of 2001, some 438 nuclear power plants were in operation in the world, representing an installed capacity of 353 GWe, supplying some 6% of total primary energy consumption and around 15% of total electricity generation. Some 80% of the total nuclear capacity is operated in OECD countries, where the nuclear energy share is higher than worldwide, corresponding to nearly one quarter of total electricity generation.

It is important to note that nuclear electricity generation, being practically carbon free, contributes to alleviating the risk of global warming and climate change. So far, in OECD countries, nuclear energy has been a main factor in reducing or stabilising greenhouse gas emissions in spite of growing energy consumption. Globally, nuclear-generated electricity is responsible for reducing greenhouse gas emissions from the energy sector by some 8% each year. Furthermore, nuclear power plants and fuel cycle facilities require less land and water than most other energy systems and do not release particulate matter or gases, such as sulphur and nitrogen oxides, responsible for acid rain, urban smog and depletion of the ozone layer.

The contribution of nuclear energy to diversity and security of supply is also worth noting. Nuclear energy alleviates dependency on hydrocarbons, a key driving factor in energy policies of some OECD countries, such as Japan or France where oil and gas reserves are insignificant. Security of supply is an intrinsic characteristic of nuclear energy since nuclear fuel is easy and cheap to stock and uranium resources are widely distributed in the world.

Current trends in the field of nuclear energy are characterised by a very modest growth in the number of plants in operation, although nuclear installed capacity and electricity generation continue to grow owing to plant up-rating and increased capacity factors. Only a few new nuclear power plants are under construction or being planned in OECD countries, mostly in the OECD Pacific region, Japan and the Republic of Korea. In Europe and North America the plans are to continue operating existing plants, often beyond their originally licensed lifetime and a few countries are starting to contemplate ordering new units, led by Finland. Some countries such as Belgium, Germany and Sweden intend to accelerate the closing down of their plants.

However, nuclear energy technologies are progressing steadily owing to R&D and development programmes supported by governments and the industry. Continuing technology progress and feedback from experience are leading to enhanced performance of nuclear power plants in operation. Trends in average capacity factors are illustrative of this progress with an increase of more than 8% between 1990 and 2000, from 77.2% to 85.9%. In the United States, the average capacity factor of the 104 reactors in service reached 89.7% in 2001 and would have been 90.7% if Browns Ferry 1 - which has not been operated for many years although it holds an operating license - was excluded.

Authorised lifetime extensions, for example beyond 40 years in the United Kingdom and up to 60 years in the United States, are an indicator of industrial maturity and robust technology progress. Refurbishment, safety upgrades and life extension will allow nuclear energy to maintain a competitive contribution to global supply up to 2020 and slightly beyond. Further on, however, a new generation of nuclear systems will be needed.

Since the first deployment of nuclear energy systems, constant progress has been achieved regarding safety, health and environmental protection. Examples illustrating enhanced safety and health protection performance include the decrease in unplanned automatic scrams and industrial safety accidents. According to the data collected by the World Association of Nuclear Operators (WANO) covering more than 400 nuclear units in 2000, unplanned automatic scrams per 7 000 hours critical went from 1.8 to 0.6 between 1990 and 2000.

Throughout the world, occupational exposures at nuclear power plants have been steadily decreasing since the late 1980s as shown by the data collected through the Information System on Occupational Exposure (ISOE), jointly managed by the NEA and the IAEA. The average collective dose per reactor for all operating reactors included in ISOE, representing 88% of the commercial nuclear reactors in operation worldwide, followed a downward trend from 2.5 man.Sv in 1987 to around 1.2 man.Sv in 1999.

In the OECD countries, industrial nuclear facilities have excellent records regarding global safety and trends show continued progress in this regard. The industrial safety accident rate tracks the number of accidents resulting in loss of work-time, restricted work or fatalities. Worldwide, this rate went from 5.50 per million man-hours worked in 1990 to 1.63 in 2000.

Regarding environmental protection, the decrease of solid radioactive waste volumes is an important indicator of improved performance. WANO data show an average reduction by a factor of three over the last decade, from 108 m3/unit in 1990 to 39 m3/unit in 2000. Fuel cycle facilities have experienced similar trends in the reduction of volumes and activity of nuclear waste.

The competitiveness of nuclear electricity depends not only on the performance of nuclear power plants and fuel cycle facilities but also on the prices of alternatives. The volatility of hydrocarbon market prices has been a driving factor in the evolution of nuclear versus fossil-fuelled electricity cost ratios from the 1970s to the end of the last century. While the relatively low fossil fuel prices prevailing today are challenging the competitiveness of alternative sources, such as nuclear energy, the successive oil crises have highlighted the potential benefits of diversity and security of energy supply that are provided by including non-fossil fuel options.

Existing nuclear power plants are competing very well in deregulated electricity markets, as demonstrated by the experience of several OECD countries. Their low marginal costs and high reliability give nuclear units an advantage in open markets. In the long run, once capital costs have been incurred, nuclear units become the cheapest electricity source in many countries. Nuclear energy may become even more competitive if and when national policies will be implemented to internalise external costs, such as climate change and other environmental burdens. Indeed, since the price of nuclear electricity already internalises in most countries the cost of decommissioning nuclear facilities and the disposal of high-level waste, its external costs are very low compared to those of most alternatives.

Advanced nuclear energy systems available today

Nuclear power plants under construction and planned, as well as reactor concepts ready for commercial deployment, include a number of advanced evolutionary concepts and some more innovative systems. This generation of reactors and fuel cycles, although largely based upon existing technologies, integrates lessons learnt through the past operation of nuclear systems and a broad range of improvements in design, safety, reliability and economic aspects. The main goal of those systems is to generate electricity in a safe and reliable manner at low cost.

More efficient use of natural resources and waste minimisation are important parameters also taken into account in new designs. Efficiency improvements may be obtained by various means including high-temperature reactors, high burn-up fuels and the recycling of fissile materials. Finally, some high-temperature reactors open additional markets.

Examples of advanced nuclear systems that are being built or could be commissioned before 2010-2015 include advanced light water reactors (e.g. ABWR, AP600/1000, EPR), advanced pressurised heavy water reactors (e.g. CANDU NG) and high-temperature gas-cooled reactors (e.g. Pebble Bed Modular Reactors). A number of other water reactor concepts, liquid-metal-cooled reactors and advanced fuel cycle options are at similar stages of development.

Recognising that high capital cost is a major barrier to a larger commercial deployment of nuclear energy, designers of advanced systems have implemented proven means and adopted new approaches to reduce those costs. Key elements in this regard include streamlining designs, relying on passive safety and moving to risk-informed safety, developing digital instrumentation and using components with built-in diagnostics.

A number of advanced evolutionary designs, such as most of the advanced water-cooled reactors, take advantage of economies of scale for reducing capital costs, while other more innovative approaches based upon modularity and factory building are adopted by others, such as high-temperature reactors. The former favours large units, 1 GWe and more, the latter aims at small units, around 100 MWe, that may be connected to a small grid but could also be built as multiple unit stations in large networks.

Other means to reduce the capital costs of advanced nuclear systems include enhanced construction techniques. Construction time has a direct impact on capital cost through the interest paid during construction and an indirect impact on financial risk and profitability by delaying the commissioning of the plant and thereby the revenue flow. Methods for reducing construction time adopted for nuclear power plants built recently and proposed for evolutionary advanced reactors include the use of modularisation and prefabrication of civil structures and components and slip-forming techniques.

Regarding safety, the defence-in-depth concept remains the overriding strategy to meet the requirements of increasingly stringent regulations. The trend in new innovative designs is to ensure a higher degree of independence between the successive levels of defence in depth. Also, emphasis is placed on improvements aiming at avoiding the need for off-site emergency measures in case of accidents.

Waste minimisation is not a high priority for most advanced designs but improved efficiency, motivated primarily by economic objectives, contributes to reducing fuel consumption and thereby the weight of solid radioactive waste arising. Advanced technologies for radioactive waste and spent fuel conditioning and management can reduce the volumes and in some cases the toxicity of nuclear waste to be disposed of in final repositories.

Innovative technologies for tomorrow

A review of ongoing R&D programmes on new nuclear energy systems shows a wealth of ideas and projects covering a wide range of technical options and development stages. This was demonstrated, for example, by more than 100 responses to the call by the USDOE in 2001 for information on new, innovative nuclear energy systems under investigation or development.

R&D efforts under way on nuclear energy systems cover a broad range of reactor technologies and fuel cycle options and rely on a wide variety of evolutionary and innovative approaches. Concepts considered by research teams range from classic water-cooled reactors incorporating innovative options, such as the integral pressurised-water-cooled concepts, to radically non-classical approaches such as vapour core, molten-salt-cooled reactors, through high-temperature reactors and liquid-metal-cooled reactors with advanced fuel cycle options such as pyroprocessing technologies.

Several international initiatives have been launched recently to address the challenges facing nuclear energy. Innovative reactor and fuel cycle concepts considered in those frameworks aim at achieving excellent performance in terms of economics, environmental protection, safety and reliability, and non-proliferation and physical protection. Also, specific attention is devoted to responding to public concerns in order to facilitate the deployment of nuclear energy. The major objective of international endeavours is to strengthen co-operation and the overall efficiency of programmes aiming at the development of the next generation of nuclear energy systems.

A project on innovative reactors carried out jointly by three international agencies, including the NEA, proposed a methodology to assess opportunities for cross-cutting multinational or international R&D in support of innovative designs offering potential for the future. The approach adopted for assessing the expected performance of innovative reactor designs focused on reviewing six key characteristics: safety, economic competitiveness, proliferation resistance and safeguards, waste management, efficiency of resource use and flexibility of application. The findings and recommendations of the project included strong encouragement of cross-cutting R&D, in particular on enabling technologies, and international co-operation.

Several countries sharing a common interest in R&D for the next generation of nuclear energy systems, have established, linked to a USDOE initiative, the Generation IV International Forum (GIF) as a framework for international co-operation in the field. Ten countries are Members of GIF at present, and the NEA, the IAEA and the EC are participating as observers. During the present phase of the project, the NEA is providing technical support to some of the GIF working groups. When co-operative R&D projects will be implemented, it is anticipated that the NEA could be asked to serve as the Secretariat to some of them.

The first phase of the GIF initiative is to establish a road map for R&D programmes aiming at the development of a next generation of nuclear energy systems that can be licensed, constructed and operated in a manner that will provide a competitively priced and reliable supply of energy while satisfactorily addressing nuclear safety, waste, proliferation and public perception issues. The six to eight concepts that will eventually be selected for further co-operative R&D efforts are intended to offer high potential to reach these objectives and a reasonable likelihood to be available for deployment by 2030.

The goals of this next generation of nuclear energy systems as defined within GIF are: sustainability, safety and reliability, economics, and non-proliferation and physical protection. A methodology has been developed to evaluate concepts against those goals using a set of qualitative and quantitative criteria. In addition, the specific capabilities of various concepts to efficiently produce process heat, potable water and/or hydrogen, and to facilitate the management of waste will be taken into account in the selection of systems offering the highest potential.

Concluding remarks

In a world that will need increasing quantities of energy and will want to preserve its environment, nuclear energy has large potential. It can supply a significant share of the energy products that people will need, such as heat, electricity, hydrogen and potable water, at affordable costs and without jeopardising natural resources and the environment. Realising the potential of nuclear energy, however, will require sustained R&D efforts covering a wide range of disciplines and technologies.

Ongoing R&D programmes on nuclear energy systems for the future are focusing on responding to society's needs and concerns. Accordingly, efficient use of natural resources, reduction of volumes and toxicity of radioactive waste, and safety systems minimising the risk of off-site impacts of accidents are key goals of innovative nuclear reactors and fuel cycles.

International co-operation offers unique opportunities to maintain a significant R&D momentum while controlling costs in an increasingly competitive economic context. One of the key added values of international endeavours is to bring synergy and enhance the efficiency of national programmes. Pooling resources together and carrying out jointly capital or manpower intensive studies not only reduces the cost for each participant country but also offers opportunities for creating more dynamic scientific teams in a multicultural environment.

The role of intergovernmental organisations such as the NEA is important in this regard. Given its experience in joint projects and its structure adapted to international co-operation, the NEA can play an important role as a catalyst in support of ambitious R&D endeavours for a successful future of nuclear energy. The expertise and management skills available within the NEA Secretariat can provide interested Member countries with a robust and flexible framework to efficiently carry out background studies and co-ordinate research projects undertaken by various national teams and laboratories.

Eventually, however, civil society's perception of nuclear energy and its risks compared to alternatives will be a driving factor in the choices between different sources and technologies and future energy mixes.

 

Related links

NEA Nuclear Development Programme

G8 Energy Ministerial Meetings and Related Documents (University of Toronto)