The future lies in the past1 October 2003
The Massachusetts Institute of Technology has recently issued a study titled "The Future of Nuclear Power". The study analyses what would be required to retain nuclear power as a significant option for reducing greenhouse gas emissions and meeting growing needs for electricity supply up to the year 2050.
Over the next 50 years, unless patterns change dramatically, energy
production and use will contribute to global warming through large-scale greenhouse gas emissions. Nuclear power could be one option for reducing carbon emissions. At present, however, this is unlikely; nuclear power faces stagnation and decline. That is how a study carried out by the Massachusetts Institute of Technology (MIT) titled The Future of Nuclear Power begins its introduction.
The MIT study states that the nuclear power option will only be exercised if the technology demonstrates better economics; improved safety; successful waste management; low proliferation risk; and if public policies place a significant value on electricity production that does not produce carbon dioxide.
The study did not analyse other options for reducing carbon emissions renewable energy sources, carbon sequestration, and increasing energy efficiency. The study could not, therefore, reach any conclusions about
priorities among these efforts and nuclear power.
In 2002, nuclear power supplied
20% of the US and 17% of world
electricity consumption. It has been
generally predicted that worldwide
electricity consumption will increase substantially in the coming decades, especially in the developing world, accompanying economic growth and social progress. However, official forecasts call for a mere 5% increase in nuclear generating capacity worldwide by 2020, and achieving even this modest target seems questionable. Electricity use could grow by as much as 75%.
The MIT study found that for a large expansion of nuclear power to succeed, four critical problems must be overcome: cost, safety, waste and proliferation.
In deregulated markets, nuclear power is not currently cost competitive with coal and natural gas. However, plausible reductions by industry in capital cost, operation and maintenance costs, and construction time could reduce the gap. Carbon emission credits, if enacted by government, can give nuclear power a cost advantage.
Modern reactor designs can achieve a very low risk of serious accidents, but best practices in construction and operation are essential.
Public perception of safety is generally negative, exacerbated by the 1979 Three Mile Island and 1986 Chernobyl incidents, as well as by incidents at fuel cycle facilities in the USA, Japan and Russia. There is also growing
concern about the safe and secure transportation of nuclear materials and the security of nuclear facilities from terrorist attack.
Geological disposal is technically feasible, but execution has yet to be demonstrated. The MIT study says that a convincing case has not yet been made that the long-term waste management benefits of advanced, closed fuel cycles involving reprocessing of spent fuel are outweighed by the short-term risks and costs. Improvement in the open, once-through fuel cycle may offer waste management benefits as large as those claimed for the more expensive closed fuel cycles.
Since these radioactive wastes present some danger to present and future generations, the public and its elected representatives, as well as prospective investors in nuclear power plants, properly expect continuing and substantial progress towards solution to the waste disposal issue. Successful operation of the planned disposal facility at Yucca Mountain would ease, but not solve, the waste issue for the USA if nuclear power expands substantially.
The current international safeguards regime is inadequate to meet the security challenges of the expanded nuclear deployment contemplated in the global growth scenario. The reprocessing system currently used in Europe, Japan and Russia that involves separation and recycling of plutonium presents unwarranted proliferation risks.
To preserve the nuclear option for the future requires overcoming these four challenges. These challenges will escalate if a significant number of new nuclear generating plants are built in a growing number of countries. The effort to overcome these challenges is only justified if nuclear power can
significantly contribute to reducing global warming, which entails major expansion of nuclear power. In effect, preserving the nuclear option for the future means planning for growth. The MIT study concluded that over the next 50 years, the best choice to meet these challenges is the open, once-through cycle.
Public acceptance will also be critical to the expansion of nuclear power. A survey carried out by MIT suggested that the public does not yet see nuclear power as a way to address global warming, suggesting that further public education may be necessary.
The MIT study postulated a global growth scenario that, by 2050, would see 1000-1500 reactors each of 1000MWe capacity deployed worldwide, compared to a capacity equivalent of 366 reactors of comparable
size now in service. An illustrative deployment of 1000 reactors, each of 1000MWe, under this scenario is given in Table 1.
This scenario would displace a significant amount of carbon-emitting fossil fuel generation. In 2002, carbon equivalent emission from human activity was about 6500 million tonnes per year. These emissions will probably more than double by 2050. The 1000GWe of nuclear power postulated in the MIT scenario would avoid annually about 800 million tonnes of carbon equivalent if the electricity generation displaced was gas-fired, and 1800 million tonnes if the generation was coal-fired, assuming no capture and sequestration of carbon dioxide from combustion sources.
Fuel cycle choice
A critical factor for the future of an expanded nuclear power industry is the choice of the fuel cycle. This choice affects all four key problems confronting nuclear power. The MIT study examined three representative nuclear fuel cycle deployments.
• Conventional thermal reactors operating in a once-through mode, in which discharged spent fuel is sent directly to disposal.
• Thermal reactors with reprocessing in a closed fuel cycle. This includes the fuel cycle currently used in some countries in which plutonium is separated from spent fuel, and fabricated into MOX fuel, and recycled to reactors for one pass.
• Fast reactors with reprocessing in a balanced closed fuel cycle. The fast reactors, reprocessing and fuel
fabrication facilities would be co-located in secure nuclear energy parks in industrial countries.
Advanced fuel cycles add considerably to the cost of nuclear electricity. MIT considered reprocessing and one-pass fuel recycle with current technology, and it found that the fuel cost, including waste storage and disposal charges, to be about 4.5 times the fuel cost of the once-through cycle. Thus use of advanced fuel cycles imposes a significant economic penalty on nuclear power.
The viability of the once-through alternative in a global growth scenario depends upon the amount of uranium resource that is available at economically attractive prices. MIT believes that the worldwide supply of uranium ore is sufficient to fuel the deployment of 1000GWe over the next half century and to maintain this level of deployment over a 40-year lifetime of this fleet. The known resource base of 3.1 million tonnes U identified in the Nuclear Energy Agency Red Book could increase by a factor of around 10 if uranium prices double from their current value of about $30/kgU. This assumption is based upon information from the Uranium Information Center, and the history of natural resource supply.
MIT's analysis suggests that the once-through cycle has advantages in cost, proliferation and fuel cycle safety, and is disadvantageous only in respect to long-term waste disposal. Cost and waste criteria are likely to be the most crucial for determining nuclear power's future. The MIT study believes that it is not realistic to expect that there are new reactor and fuel cycle technologies that simultaneously overcome the problems of cost, safety, waste and proliferation. As a result, the study concludes that the once-through fuel cycle best meets the criteria of low costs and proliferation resistance. MIT therefore recommended that for the next few decades, priority should be given to the deployment of the
once-through fuel cycle, rather than developing the more expensive closed fuel cycle technology.
Nuclear power will only succeed in the long run if it has a lower cost than competing technologies. This is
especially true as electricity markets become progressively less subject to economic regulation in many parts of the world.
MIT constructed a model to evaluate the real cost of electricity from nuclear power against pulverised coal plants and natural gas combined cycle plants over their economic lives. In the absence of a carbon tax, these technologies are less expensive than renewable technologies. The cost model used assumptions that commercial investors would be expected to use today, with parameters based on actual experience rather than engineering estimates. It compares the levelised price of electricity over the life of a power plant that would be necessary to cover all operating expenses and taxes and provide an acceptable return to investors. The comparative figures in Table 2 assume 85% load factor and a 40-year economic life for the nuclear plant, reflect economic conditions in the USA, and consider a range of projected improvements in nuclear cost factors.
Nuclear does become more cost competitive if the social cost of carbon emissions is internalised, for example through a carbon tax or an equivalent 'cap and trade' system. If the assumption is made that the costs of carbon emissions are imposed, Table 3 illustrates the impact on the competitive costs for different power sources.
The ultimate cost will depend on both societal choices, such as how much carbon emission to permit, and technological developments, such as the cost and feasibility of large-scale carbon capture and long-term sequestration.
The carbon-free nature of nuclear power argues for government action to encourage maintenance of the nuclear option, particularly in light of the regulatory uncertainties facing the use of nuclear power and the unwillingness of investors to bear the risk of introducing a new generation of nuclear facilities with their high capital costs.
MIT recommends three actions to improve the economic viability of nuclear power:
• The government should cost share for site banking for a number of plants, certification of new plant designs by the Nuclear Regulatory Commission, and combined construction and operating licences
for plants built immediately or in the future.
• The government should recognise nuclear as carbon free and include new nuclear plants as an eligible option in any federal or state mandatory renewable energy portfolio standard.
• The government should provide a modest subsidy for a small set of 'first mover' commercial nuclear plants to demonstrate cost and regulatory feasibility in the form of a production tax credit.
The US Department of Energy (DoE) analysis, research, development and demonstration (ARD&D) programme should support the technology path leading to the global growth scenario and include diverse activities that balance risk and timescales, in pursuit of the strategic objective of preserving the nuclear option.
MIT recommends that the DoE, perhaps in collaboration with other countries, should establish a major project for the modelling, analysis and simulation of commercial nuclear power systems. This project should provide a foundation for the accumulation of data about how variations in the operation of plants and other parts of the fuel cycle affect costs, safety, waste, and proliferation resistance characteristics. This project will require many years and
considerable resources to be carried out successfully.
MIT believes that the development of all advanced nuclear technologies should await the results of this proposed project. MIT's study suggests that there is ample time for the project to compile the necessary engineering and economic analyses and data before undertaking expensive development programmes, even if the project should take a decade to complete. Reactor concept evaluation should be part of the project.
MIT also recommends that the project's research efforts should only go into technology pathways that do not produce weapons-usable material during normal operation, for example, by leaving some uranium, fission products, and/or minor actinides with the recycled plutonium.
Government R&D support for advanced design LWRs and for the high temperature gas reactor (HTGR) is justified because these are the two reactor types that are most likely to play a role in any nuclear expansion. R&D support for advanced design LWRs should focus on measures that reduce construction and operating cost. There should be limited R&D support to resolve key issues relating to HTGR designs.
Waste management calls for a
significant and redirected ARD&D
programme. The DoE waste programme has been focused for some time on the Yucca Mountain project. MIT believes that the DoE must broaden its waste R&D effort, or
run the risk of being unable to rigourously defend its choices for waste disposal sites. More attention needs to be given to the characterisation of waste forms and engineered barriers, followed by development and testing of engineered barrier
systems. Deep boreholes, as an alternative to mined repositories, should be aggressively pursued.
MIT believes that the ARD&D programme that it proposes are aligned with the strategic objective of enabling a credible growth scenario over the next several decades. Such an ARD&D programme requires incremental budgets of almost $400
million per year over the next five years, and at least $460 million per year for the 5-10 year period.