Science for Democratic Action, August 1, 2006


[Rachel's introduction: We are told we must build more nuclear power plants to halt global warming. It may sound persuasive at first -- until the Institute for Energy and Environmental Research (IEER) examines the numbers and reveals that nuclear power almost certainly cannot expand rapidly enough to make a real difference. And if it did, it would create intractable problems of waste disposal and the spread of A-bombs worldwide.]

By Brice Smith[1]

Climate change is by far the most serious vulnerability associated with the world's current energy system. While there are significant uncertainties, the possible outcomes of global warming are so varied and potentially so severe in their ecological and human impacts that immediate precautionary action is called for.

Compared to fossil fuels, nuclear power emits far lower levels of greenhouse gases even when mining, enrichment, and fuel fabrication are taken into consideration.[2] As a result, some have come to believe that nuclear power should play a role in reducing greenhouse gas emissions.

The most important practical consideration, rarely addressed in the debate, is this: how many nuclear power plants will it take to significantly impact future carbon dioxide emissions from fossil fuel power plants? We have considered in detail two representative scenarios for the future expansion of nuclear power. The assumed worldwide growth rate of electricity is the same for both, 2.1 percent per year, comparable to values assumed in most conventional studies of the electricity sector.

Nuclear growth scenarios

The first scenario was taken from a 2003 study from the Massachusetts Institute of Technology.[3] In this report, the authors envisioned a "global growth scenario" with a base case of 1,000 gigawatts (GW) of nuclear capacity installed around the world by 2050. Since all of the reactors in operation today would be shut down by mid-century, this would represent a net increase of roughly a factor of three over today's effective capacity. To give a sense of scale, this proposal would require one new reactor to come online somewhere in the world every 15 days on average between 2010 and 2050.

Despite the increase in nuclear power envisioned under the global growth scenario, the proportion of electricity supplied by nuclear power plants would increase only slightly, from about 16 percent to about 20 percent. As a result, fossil fuel-fired generation would also grow and the emissions of carbon dioxide, the most important greenhouse gas, from the electricity sector would continue to increase.

In order to consider a more serious effort to limit carbon emissions through the use of nuclear power, we developed the "steady-state growth scenario." Using the same electricity demand growth assumed in the MIT report, we calculated the number of nuclear reactors that would be required to simply maintain global carbon dioxide emissions at their year 2000 levels.

Considering a range of assumptions about the future contribution of renewables and natural gas fired plants, we found that between 1,900 and 3,300 GW of nuclear capacity would be required to hold emissions constant. For simplicity we used 2,500 GW as the alternative case study. This scenario is roughly equivalent to assuming that nuclear plays about the same role in the global electricity sector in the year 2050 as coal does today in the United States.

In order to significantly reduce carbon dioxide emissions, nuclear power plant construction would have to be more rapid than one a week. We have not considered such scenarios, since the dangers of using nuclear energy to address greenhouse gas emissions are amply clear in the two scenarios discussed here.

Evaluating the scanarios

Given that both time and resources are limited, a choice must be made as to which sources of electricity should be pursued aggressively and which should not. The best mix of alternatives will vary according to local, regional, and country-wide resources and needs. In making a choice, the following should serve to help guide the selection:

1. The options must be capable of making a significant contribution to a reduction in greenhouse gas emissions, with a preference given to those that achieve more rapid reductions;

2. The options should be economically competitive to facilitate their rapid entry into the market; and,

3. The options should minimize other environmental and security impacts and should be compatible with a longer term vision for creating an equitable and sustainable global energy system.

It is within this context that the future of nuclear power must be judged.


The largest vulnerability associated with a large expansion of nuclear power is likely to be its connection to the potential proliferation of nuclear weapons. In order to fuel the global or steady-state growth scenarios, the world's uranium enrichment capacity would have to increase by approximately two and half to six times.[4] Just one percent of the enrichment capacity required by the global growth scenario would be enough to supply the highly-enriched uranium for nearly 210 nuclear weapons every year. Reprocessing the spent fuel would add significantly to these security risks (see below). Proposals to reduce the risks of nuclear weapons proliferation are unlikely to be successful in a world where the five acknowledged nuclear weapons states seek to retain their arsenals indefinitely. The institutionalization of a system in which some states are allowed to possess nuclear weapons while dictating intrusive inspections and restricting what activities other states may pursue is not likely to be sustainable. As summarized by Mohamed ElBaradei, director general of the International Atomic Energy Agency: "We must abandon the unworkable notion that it is morally reprehensible for some countries to pursue weapons of mass destruction yet morally acceptable for others to rely on them for security -- indeed to continue to refine their capacities and postulate plans for their use."[5]

Without a concrete, verifiable program to irreversibly eliminate the tens of thousands of existing nuclear weapons, no nonproliferation strategy is likely to be successful no matter how strong.


The potential for a catastrophic reactor accident or well coordinated terrorist attack to release a large amount of radiation is another unique danger of nuclear power. Such a release could have extremely severe consequences for human health and the environment. The so- called CRAC-2 study conducted by Sandia National Laboratories estimated that a worst case accident at an existing nuclear plant in the United States could, for some sites, result in tens of thousands of prompt and long-term deaths and cause hundreds of billions of dollars in damages.[6] Even if a reactor's secondary containment was not breached, a serious accident would still cost a great deal. As summarized by Peter Bradford, a former commissioner of the U.S. Nuclear Regulatory Commission (NRC):

"The abiding lesson that Three Mile Island taught Wall Street was that a group of N.R.C.-licensed reactor operators, as good as any others, could turn a $2 billion asset into a $1 billion cleanup job in about 90 minutes."[7]

Despite the importance of reactor safety, the probabilistic risk assessments used to estimate the likelihood of accidents have numerous methodological weaknesses that limit their usefulness. First, the questions of completeness and how to incorporate design defects are particularly difficult to handle. Second, concerns arise due to the fact that nuclear power demands an extremely high level of competence at all times from the regulators and managers all the way through to the operators and maintenance crews. Finally, the increased use of computers and digital systems create important safety tradeoffs, with improvements possible during normal operation, but with the potential for unexpected problems to arise during accidents. In light of the uncertainties inherent in risk assessments, William Ruckelshaus, the head of the U.S. Environmental Protection Agency under both Presidents Nixon and Reagan cautioned that:

"We should remember that risk assessment data can be like the captured spy: if you torture it long enough, it will tell you anything you want to know."[8]

In the nearly 3,000 reactor-years of experience at power plants in the United States, there has been one partial core meltdown and a number of near misses and close calls. From this, the probability of such an accident occurring is estimated to be between 1 in 8,440 and 1 in 630 per year.[9] Using the median accident probability of 1 in 1,800 per year, and retaining the assumption from the MIT report that future plants will be ten times safer than those in operation today, we find that the probability of at least one accident occurring somewhere in the world by 2050 would be greater than 75 percent for the global growth scenario, and over 90 percent for the steady-state growth scenario.

The possibility that public opinion could turn sharply against the widespread use of nuclear power following an accident is a significant vulnerability. If nuclear power was in the process of being expanded, public pressure following an accident would leave open few options. On the other hand, if long-term plans to phase out nuclear power were already being carried out, there would be far more options available and those options could be accelerated with less disruption to the overall economy.

Spent Fuel

There is also the difficulty of managing radioactive waste. The existence of weapons-usable plutonium in the waste complicates the problem. While the management of low-level waste will continue to pose a challenge, by far the largest concern is how to handle spent nuclear fuel.

Complicating this task are the long half-lives of some of the radionuclides present in the waste (for example: plutonium-239, half- life 24,000 years; technetium-99, half-life 212,000 years; and iodine-129, half-life 15.7 million years).

Through 2050, the global growth scenario would lead to nearly a doubling of the average rate at which spent fuel is generated, with proportionally larger increases under the steady-state growth scenario. Assuming a constant rate of growth, a repository with the capacity of Yucca Mountain (70,000 metric tons) would have to come online somewhere in the world every five and a half years in order to handle the waste that would be generated under the global growth scenario. For the steady-state growth scenario, a new repository would be needed every three years on average.

The characterization and siting of repositories rapidly enough to handle this waste would be a very serious challenge. Yucca Mountain has been studied for more than two decades, and it has been the sole focus of the U.S. Department of Energy (DOE) repository program since 1987. Despite this effort, and nearly $9 billion in expenditures, to date no license application has yet been filed. In fact, in February 2006, Secretary of Energy Samuel Bodman admitted that the DOE can no longer make an official estimate for when Yucca Mountain might open due to ongoing difficulties faced by the project.

Internationally, no country plans to have a repository in operation before 2020, at the earliest, and all repository programs have encountered problems during development. Even if the capacity per repository is increased, deep geologic disposal will remain a major vulnerability of a much-expanded nuclear power system.

Alternatives to repository disposal are unlikely to overcome the challenges posed by the amount of waste that would be generated under the global or steady-state growth scenarios. Proposals to reprocess the spent fuel would not only not solve the waste problem, but would greatly increase the dangers. Reprocessing schemes are expensive and create a number of serious environmental risks while still generating large volumes of waste destined for repository disposal. In addition, reprocessing results in the separation of weapons-useable plutonium, adding significantly to the risks of proliferation. While future reprocessing technologies like UREX+ or pyroprocessing could have some nonproliferation benefits, they would still pose a significant risk if deployed on a large scale. Under the global growth scenario, the authors of the MIT study estimate that more than 155 metric tons of separated plutonium would be required annually to supply the required MOX (mixed-oxide) fuel. Just one percent of this commercial plutonium would be sufficient to produce more than 190 nuclear weapons every year.

The authors of the MIT study acknowledge the high cost and negative impacts of reprocessing and, as such, advocate against its use. Instead they propose interim storage and expanded research on deep borehole disposal. It is possible that deep boreholes might prove to be an alternative in countries with smaller amounts of waste. However, committing to a large increase in the rate of waste generation based only on the potential plausibility of a future waste management option would be to repeat the central error of nuclear power's past. The concept for mined geologic repositories dates back to at least 1957. However, turning this idea into a reality has proven quite difficult, and not one spent fuel rod has yet been permanently disposed of anywhere in the world.


Nuclear power is likely to be an expensive source of electricity, with projected costs in the range of six to seven cents per kilowatt-hour (kWh) for new reactors. Tables 1 and 2 show data from the MIT study and a study conducted at the University of Chicago.[10] Table 1 shows estimates used for the projected capital costs, construction lead times and interest rate for natural gas, coal and nuclear power in the United States. Table 2 show estimates of cost per kilowatt- hour.

While a number of potential cost reductions have been considered by nuclear power proponents in the United States, it is unlikely that plants not heavily subsidized by the federal government would be able to achieve these. This is particularly true given that the cost improvements would have to be maintained under the very demanding timetables set by the global or steady-state growth scenario.

Promising Alternatives

A number of energy alternatives that are economically competitive with new nuclear power are available in the near to medium term.[11] The choice between these alternatives will hinge primarily on the rapidity with which they can be brought online and on their relative environmental and security impacts.

Of the available near-term options for reducing greenhouse gas emissions, the two most promising ones in the United States and other areas of the Global North are increasing efficiency and expanding the use of wind power at favorable sites. At approximately four to six cents per kWh, wind power at favorable sites in the United States is already competitive with natural gas or new nuclear power. With the proper priorities on upgrading the transmission and distribution infrastructure and changing the way the electricity sector is regulated, wind power could expand rapidly in the United States. In fact, without any major changes to the existing grid, wind power could expand to 15 to 20 percent of U.S. electricity supply, as compared to less than one-half of one percent in 2003, without negatively impacting overall stability or reliability.

Improvements in energy efficiency could continue to be made in the medium term as well. For example, as the current building stock turns over, older buildings could be replaced by more efficient designs. In addition, the utilization of wind power, thin-film solar cells, advanced hydropower at existing dams, and some types of sustainable biomass could allow renewables to make up an increasingly significant proportion of the electricity supply over the medium term. This expansion of renewables could be facilitated through the development of a robust mix of technologies, the development of strengthened regional grids to help stabilize the contribution of wind and solar power through geographic distribution, the use of pumped hydropower systems to store excess electricity during times of low demand, and the tighter integration of large scale wind farms with natural gas fired capacity.[12]

While it would require a significant effort to implement new efficiency programs and to develop the necessary infrastructure to expand wind power, these efforts must be compared to the difficulties that would be encountered in restarting a nuclear power industry that hasn't had a new order placed in the United States in more than 25 years and hasn't opened a single new plant in the last ten years. In addition, the current fossil fuel based energy system is very expensive to maintain. For example, the International Energy Agency estimates that the amount of investment in oil and gas between 2001 and 2030 will total nearly $6.1 trillion, with 72 percent of that going towards new exploration and development efforts.

Transition technologies

Energy efficiency and renewable energy programs have few negative environmental or security impacts compared to our present energy system and, in fact, have many advantages. As a result, these options should be pursued to the maximum extent possible. However, in order to stabilize the climate, it appears likely that some energy sources with more significant tradeoffs will also be needed as transition technologies.

The two most important transition strategies are increased reliance on the import of liquefied natural gas (LNG) and the development of integrated coal gasification plants (IGCC-integrated gasification combined cycle) with sequestration of the carbon dioxide emissions in geologic formations.

Compared to pulverized coal plants, combined cycle natural gas plants emit about 55 percent less CO2 for the same amount of generation. If efficiency improvements and an expanded liquidification and regasification infrastructure can stabilize the long-term price of natural gas at the cost of imported LNG, then the use of combined cycle natural gas plants is likely to remain an economically viable choice for replacing highly inefficient coal fired plants.

The use of coal gasification technologies would greatly reduce the emissions of mercury, particulates, and sulfur and nitrogen oxides from the burning of coal. However, for coal gasification to be considered as a potentially viable transition technology, it must be accompanied by carbon sequestration, the injection and storage of CO2 into geologic formations. Experience in the United States with carbon dioxide injection as part of enhanced oil recovery has been gained since at least 1972. In addition, the feasibility of sequestering carbon dioxide has been demonstrated at both the Sleipner gas fields in the North Sea and the In Salah natural gas fields in Algeria. While the costs of such strategies are more uncertain than those of other mitigation options, estimates for the cost of electricity from power plants with carbon sequestration still fall within the range of six to seven cents per kWh.

Some of the most troubling aspects of coal, such as mountain top removal mining, would be mitigated by the reduction in demand due to increased efficiency and the rapid expansion of alternative energy sources. In addition, it appears likely that coal gasification and carbon sequestration would be better suited to the Western United States given the greater access to oil and gas fields which have already been explored and which offer the potential for added economic benefits from enhanced oil and gas recovery. On the other hand, the Eastern United States would appear better suited for an expanded use of LNG during the transition given the existing regasification capacity, the well developed distribution system, and the shorter transportation routes from the Caribbean, Venezuela, and Western Africa.

The continued use of fossil fuels during the transition period will have many serious drawbacks. However, these must be weighed against the potentially catastrophic damage that could result from global warming and against the unique dangers that accompany the use of nuclear power. To trade one uncertain but potentially catastrophic health, environmental and security threat for another is not a sensible basis for an energy policy.

No energy system is free of negative impacts. The challenge is to choose the least bad mix of options in the near to medium term while achieving significant global reductions in CO2 emissions, and to move long term toward the development of a sustainable and equitable global energy system.


Just as the claim by Atomic Energy Commission Chairman Lewis Strauss that nuclear power would one day be "too cheap to meter" was known to be a myth well before ground was broken on the first civilian reactor in the United States, and just as the link between the nuclear fuel cycle and the potential to manufacture nuclear weapons was widely acknowledged before President Eisenhower first voiced his vision for the "Atoms-for-Peace" program, a careful examination today reveals that the expense and vulnerabilities associated with nuclear power would make it a risky and unsustainable option for reducing greenhouse gas emissions. As the authors of the MIT report themselves conclude:

"The potential impact on the public from safety or waste management failure and the link to nuclear explosives technology are unique to nuclear energy among energy supply options. These characteristics and the fact that nuclear is more costly, make it impossible today to make a credible case for the immediate expanded use of nuclear power."[13]

Nuclear power is a uniquely dangerous source of electricity that would create a number of serious risks if employed on a large scale. It is very unlikely that the problems with nuclear power could be successfully overcome given the large number of reactors required for even modestly affecting carbon dioxide emissions. It has now been more than 50 years since the birth of the civilian nuclear industry and more than 25 years since the last reactor order was placed in the United States.

It is time to move on from considering the nuclear option and to begin focusing on developing more rapid, robust and sustainable options for addressing the most pressing environmental concern of our day. The alternatives are available if the public and their decision makers have the will to make them a reality. If not, our children and grandchildren will have to live with the consequences.


[1] This article is based on Insurmountable Risks: The Dangers of Using Nuclear Power to Combat Global Climate Change by Brice Smith (IEER Press, 2006). Full references can be found in the book, which is available for purchase at

[2] See Paul J. Meier, "Life-Cycle Assessment of Electricity Generation Systems and Applications for Climate Change Policy Analysis", Ph.D. Dissertation, University of Wisconsin-Madison, August 2002, online at; and, Uwe R. Fritsche, Comparison of Greenhouse-Gas Emissions and Abatement Cost of Nuclear and Alternative Energy Options from a Life-Cycle Perspective, Updated Version (Oko-Institut, Darmstadt, January 2006).

[3] John Deutch and Ernest J. Moniz (co-chairs) et al., The Future of Nuclear Power, An Interdisciplinary MIT Study, 2003, online at http: //

[4] A typical 1000 megawatt (MW) light-water reactor requires approximately 100 to 120 MTSWU per year in enrichment services to provide its fuel. For simplicity in this calculation we have assumed 110 MTSWU per year would be required for future reactors. (MTSWU stands for metric ton separative work unit, a complex unit that essentially represents the amount of effort required to achieve a given level of enrichment.)

[5] Mohamed El Baradei, "Saving Ourselves from Self-Destruction", New York Times, February 12, 2004.

[6] Jim Riccio, Risky Business: The Probability and Consequences of a Nuclear Accident, A Study for Greenpeace USA, 2001.

[7] Matthew Wald, "Interest in Building Reactors, but Industry Is Still Cautious," New York Times, May 2, 2005.

[8] William D. Ruckelshaus, "Risk in a Free Society", Risk Analysis, Vol. 4 No. 3, 157-162 (1984), pp. 157-158.

[9] The cited range represents our estimate for the 5-95 percent confidence interval for the average accident rate (i.e. there is a 5 percent chance that the actual accident rate is greater than 1 in 633 per year and a 5 percent chance that it is less than 1 in 8,440 per year.)

[10] The Economic Future of Nuclear Power, A Study Conducted at The University of Chicago, August 2004.

[11] The importance of the fact that the cost of all of the alternatives tend to cluster around six to seven cents per kWh was originally noted by Dr. Arjun Makhijani.

[12] Dr. Arjun Makhijani has long advocated for changes to the U.S. energy system. For a discussion of the IEER recommendations put forth by Dr. Makhijani for how to best facilitate the expansion of energy efficiency programs and the development of renewable energy resources, including actions at the state and local level, see: pp. 181-195 of Arjun Makhijani and Scott Saleska, The Nuclear Power Deception (Apex Press, New York, 1999); pp. 48-57 of Arjun Makhijani, Securing the Energy Future of the United States: Oil, Nuclear, and Electricity Vulnerabilities and a post-September 11, 2001 Roadmap for Action, November 2001; and, pp. 7-10 of Arjun Makhijani, Peter Bickel, Aiyou Chen, and Brice Smith, Cash Crop on the Wind Farm: A New Mexico Case Study of the Cost, Price, and Value of Wind-Generated Electricity, Prepared for presentation at the North American Energy Summit Western Governors' Association, Albuquerque, New Mexico, April 15-16, 2004. All are available at

[13] Deutch and Moniz, op. cit., p. 22 (emphasis added).