The need for innovation28 September 2001
Against a background of rising demand for power, and increasing interest in reducing greenhouse gas emissions, one would expect to see a rising trend for nuclear power generation. However, such is not the case to date.
If nuclear power is to contribute significantly to meeting the power demand of the future, it has to resolve a number of issues. The main issues facing the nuclear industry are:
• Safety and security.
• The linkage between nuclear power and nuclear weapons.
• Environmental and economic aspects of nuclear power and its fuel cycle.
Each of these issues have to be addressed and resolved before nuclear power is accepted as a solution to the growth in global energy demand. Each issue can be addressed through efforts in three interrelated areas: technology; legal and institutional framework; and oversight and controls.
Today’s activities for technological development within the nuclear power industry can be characterised as taking place within the following categories:
Currently operating commercial facilities
Improvements in maintenance, operations, engineering support, fuel supply, and life extension.
Improvements in design and operation for near-term future deployment, involving moderate changes from commercial facilities that are currently operating.
Advances in the design and operation involving major departures from currently operating commercial facilities for long-term future deployment.
In recent years, a host of ideas for new power reactor designs and fuel cycles have emerged from several countries. Some of these designs could bring about a rejuvenation of nuclear power, but only if they are developed, tried and tested under conditions that encourage their success and lead to commercial fruition. The lead-time for nuclear development is long. The development and testing of a new nuclear reactor concept is expected to require 15-20 years, depending on continued political support and the availability of adequate resources. It may be considerably longer before the most promising candidate can be selected and demonstrated to become the instrument for substantial expansion of nuclear power. Vigorous actions are required to maintain and build upon the necessary expertise that has been acquired.
Evolutionary designs are required to enable plants to improve safety, physical security, radwaste management, non-proliferation, economics, and public and political acceptance.
The need for innovation
In the longer term, global power market conditions remain uncertain. Many analyses, including that from the World Energy Council, strongly support the need to retain nuclear power as an option. Continuing growth in population and energy demand, particularly in developing countries, in combination with further experience with and understanding of global climate change emphasise a global imperative for a rapid and extensive deployment of non fossil-fired plants for electricity generation.
The March 2000 Intergovernmental Panel on Climate Change (IPCC) approved a Special Report on Emission Scenarios (SRES) for the period up to 2100. These scenarios expect a large demand for non-carbon energy technologies in the period after 2020.
The projection for nuclear energy deployment is generally quite large. The scenarios foresee a varying nuclear share, but they consistently indicate a great potential for nuclear growth, from the current 350GWe to between 2000GWe and 5000GWe by 2050, and 3500GWe and 10,600GWe by 2100. The capacity range for 2050 in these scenarios translates into global nuclear power capacity additions of 50GWe to 150GWe per year during 2020-2050.
In light of the challenges mentioned above, it is difficult to foresee a five to tenfold increase in nuclear capacity based only on existing technologies. Innovative R&D activities are needed to ensure the full participation of nuclear power in the future world energy market. The following considerations need to be addressed:
• Cost. There is a need to enhance nuclear competitiveness in the deregulated energy market, especially in regions with easy access to gas and/or with small local grids, as well as for non-electric nuclear applications.
• Infrastructure compatibility. Much of the future increase in electricity demand is projected to take place in countries not very familiar with nuclear power. It is not possible for all of them to develop quickly the infrastructure for reactor operation and front end and back end fuel cycle services. Similarly, local licensing requirements for plant construction and operation should be achievable at reasonable cost.
• Safety. Through ongoing R&D, the safety of future reactors is being further increased. One objective is the practical elimination of accident sequences that could lead to large early releases of radioactivity. In order to reduce costs, this calls for innovative solutions that would increase safety by simplifying systems and making better use of advanced safety designs and features.
• Safeguards. A large worldwide increase in the number of nuclear plants and consequent increase in the amount of plutonium in spent fuel are concerns for IAEA safeguards. Even more so, however, would be the spread of critical uranium enrichment and plutonium extraction technologies.
The costs of inspections required to provide an adequate degree of assurance that states continue to honour their non-proliferation undertakings vary widely depending on the nature of the technology employed.
If a light water reactor is the baseline, the inspection effort for an on-load power reactor is approximately five times greater; a uranium enrichment plant ten times greater, and a chemical reprocessing plant 100 times greater.
Innovations in reactor designs and fuel cycle arrangements should be pursued that would allow substantial expansions of nuclear power while minimising access to nuclear materials in forms which could readily be used in nuclear weapons or other nuclear explosive devices, and to the technologies allowing their production.
Conventional uranium resources may eventually become too expensive to sustain a several-fold increase of global nuclear power based only on traditional thermal reactors. A comprehensive plan should be developed to estimate and meet the future needs.
These are the main reasons why there is a need to work on innovative reactor designs and fuel cycles in addition to the evolutionary reactors.
Innovative reactor designs
Currently 40% of the nuclear power plants under construction (23% of all capacity under construction), primarily in developing countries, fall into the small (below 300MWe) and medium (below 700MWe) size range. They incorporate the basic technologies of the current large nuclear power plants. The smaller evolutionary reactors (such as the AP600, the VVER640, the PHWR500, and Candu-6) are also based on existing plants.
However, the need for innovative R&D has been recognised by the nuclear industry and by countries that believe in the viability of nuclear power for the long term. Currently, innovative nuclear fuel cycle and reactor concepts are being performed in a number of countries, including Argentina, Canada, China, France, India, Italy, Japan, South Korea, Russia, South Africa and the USA.
Attention has focused on small and medium reactors which have various combinations of relative simplicity of design, economy of mass production, reduced siting cots, long life cores, practically unattended remote operation and centralised maintenance and refuelling services.
Russia has demonstrated commercial operation of small reactors for heat and electricity in remote areas. The USA embarked on a Nuclear Energy Research Initiative in 1999 to develop advanced reactor and fuel cycle concepts and scientific breakthroughs in nuclear technology to overcome obstacles to the expanded use of nuclear energy.
Designs for smaller units with shorter construction times and lower capital costs are under study in many countries. The aim is to produce a design that will be economical with enhanced safety and proliferation-resistant features. It is hoped that these will be easier to finance and suitable for deployment even in regions with modest electricity grids.
The Pebble Bed Modular Reactor (PBMR) from South Africa has received worldwide attention as it claims to have the desired features (including market competitiveness). The Russians also have made similar claims, although at a larger size, for their lead-cooled fast reactor.
Innovative nuclear fuel cycles
From early in the development of nuclear power, the closed cycle scheme with breeder reactor was perceived as the best option for large-scale nuclear energy deployment. However, break-through efforts are now needed to cope with a number of issues emerging from non-proliferation, environmental mitigation, economics, and enhanced safety and security needs.
The main aims of innovative fuel cycles are:
• Economic competitiveness of fuel cycles.
• Minimisation of radioactive waste.
• Furtherance of non-proliferation aims, namely that nuclear materials cannot be easily acquired or readily converted for non-peaceful purposes.
• Further enhancement of safety through technological processes.
Although large-scale programmes on innovative fuel cycles are not implemented at present, many countries with nuclear power programmes are investigating them.
While current R&D programmes share common goals, their approaches and specific objectives differ. One result is a wide diversity of reactor and fuel cycle concepts. Some programmes are taking a new look at older concepts where improvements in materials and other technologies have made them viable now. Others are attempting to introduce innovative systems in place of more conventional ones in order to achieve substantial improvements. Yet others have decided to explore radically new options.
Innovative R&D today covers practically all major nuclear fuel cycle and reactor types – light water, heavy water, gas cooled and liquid metal reactors – with other types also being explored. Some 40 to 50 concepts are under development, some of which are in the initial conceptual design stages and a few are proceeding toward construction of prototypes or demonstration units.
A wider diversity also exists for the requirements in areas such as safety, radwaste management, non-proliferation, resource consumption and types of energy applications.
For example, on the question of economics, although all concepts aim to be competitive there are different opinions as to whether they should become competitive by taking into account potential introduction of carbon taxes and increases of fossil fuel prices, or not.
In terms of safety, some believe that today’s advanced light water reactors are sufficiently safe for large-scale development, because they are neighbour-friendly (no significant release of off-site radioactivity in the case of a severe accident). Others insist that the public will accept large-scale nuclear energy deployment only if a new reactor type is proposed with no significant fuel failure, as sometimes claimed for modular high temperature reactors.
In the waste management area, some believe that direct underground disposal of spent fuel is a sufficiently safe option and that to ensure public acceptance only its practical demonstration is needed. Others insist that the elimination of nuclear long-lived hazardous nuclides, by burning or transmuting them, is necessary to raise public support for large-scale nuclear energy deployment.
In the area of non-proliferation, some propose to develop special “proliferation-resistant” reactors and fuel cycle concepts (new types of fuel, new reprocessing technologies without the extraction of plutonium, new concepts of fast reactors, and so on) with increased reliance on intrinsic technical features against possible diversion of nuclear material. There is, however, no consensus among researchers as to how to measure the level of “proliferation resistance” and to what extent we should increase our reliance on technical measures.
The nuclear community must find a way to reduce the multiplicity of options and settle on the few that hold the most promise for successful development.
TablesSmall and medium nuclear reactors under development Innovative technologies related to the nuclear fuel cycle