"Though we have acheived progress, our work is not over. That is why I support the mission of the Arms Control Association. It is, quite simply, the most effective and important organization working in the field today." 

– Larry Weiler
Former U.S.-Russian arms control negotiator
August 7, 2018
Letters to the Editor

Reprocessing Is Less Risky

Steve Fetter and Frank von Hippel notwithstanding (“Is U.S. Reprocessing Worth the Risk?,” ACT, September 2005), new reprocessing technologies can increasingly make plutonium inaccessible for diversion by terrorist groups and by governments and can reinforce the ability of the United States to oppose the spread of current pluto­nium-separation tech­nology to additional countries.

Like it or not, nuclear reactors are destined to play a much larger role in the world’s energy mix. Those among us who are serious about international stability and controlling nuclear weapons must get to understand what modern nuclear technology can and cannot do.

Fetter and von Hippel make a convincing case against cycling plutonium back into today’s reactors. We fully agree, and in fact one of us [George S. Stanford] has published a technical analysis making that very point.

Nonetheless, we have to flag a serious problem. Fetter and von Hippel equate reprocessing with plutonium separation, a blanket association that is no longer valid. Their narrow focus on the drawbacks of current recycling technology—PUREX reprocessing and mixed-oxide (MOX) fuel in thermal reactors—could be taken to mean that all recycling of reactor fuel is to be deplored. This is definitely not the case.

The expansion of nuclear power will necessitate the processing of reactor fuel. The important point is that the recycling must be into new-generation fast reactors. Current thermal reactors, with or without recycle, can extract no more than a hundredth of the energy in the original ore.

Metal-fueled fast reactors, which Fetter and von Hippel dismiss without serious consideration, are the key.

  • Their fuel cycle is proliferation-resistant since the nature, amount, and disposition of plutonium are limited as outlined below.
  • They can consume plutonium and other long-lived actinides (such as uranium, neptunium, and americium), reducing to less than 500 years the required isolation time for waste in a repository, and postponing, perhaps indefinitely, the need for more repositories.
  • Their fuel can be recycled pyrometallurgically, a procedure that is inherently incapable of separating pure plutonium from used reactor fuel. To make it chemically pure enough to be used for weapons, a proliferator must process it further in a PUREX-type facility.
  • They can extract all the energy, making uranium a power source that can last indefinitely.

The world is already awash in reactor- and weapons-grade plutonium, and the supply is increasing daily in spent fuel from current reactors. Fast reactors with pyroprocessing will increasingly make that plutonium inaccessible for diversion.

  • Fast reactors can be set up to be net consumers of plutonium or to breed plutonium, but that does not give them any special proliferation potential because any reactor can be subverted for the production of weapons-grade plutonium and a fast reactor is no worse than any other. All reactors need safeguards to prevent diversion.
  • They take plutonium out of storage and out of commerce. Once plutonium has entered an integrated fast-reactor/pyroprocessing facility (IFR), none ever needs to come out unless more is wanted to prime new reactors.
  • Diversion by terrorists would be essentially impossible from an IFR system. A Livermore National Laboratory study has shown that, even given successful diversion, the heat generation alone from pyroprocessed fuel would be so intense that a bomb’s high explosive (not the plutonium) would self-detonate or melt. Not even a nation seeking nuclear weapons would waste any time on it.

The key to preventing proliferation during the inevitable worldwide expansion of nuclear power is a concerted effort to amend the nuclear Nonproliferation Treaty to eliminate the right of each nation to develop its own full-scale fuel cycle. In return, the “nuclear club” needs formally to guarantee fuel supplies and waste disposal at reasonable prices through an international entity such as the International Energy Agency or the International Atomic Energy Agency. The negotiations will not be easy, but because preventing proliferation is in everyone’s interest, they may succeed.

Fetter and von Hippel say that reprocessing would be too expensive, a claim that is true of PUREX and thermal reactors but has two serious problems in the context of pyroprocessing and fast reactors. First, it neglects external costs. The overall cost of energy from a given source depends not only on direct costs, but also on “externalities,” the hard-to-quantify costs of outside effects. Economic comparisons that ignore such costs are unrealistic and misleading. For example, burning coal causes thousands of excess deaths per year in the United States alone. Fissioning uranium in nuclear reactors causes none, nor does it release carbon dioxide. By absorbing such external costs, society subsidizes fossil-fueled power.

The second error is the assumption that, even neglecting externalities, costs are well established. They’re not. At least one external analysis concludes that an IFR-type system would be competitive. By contrast, Fetter and von Hippel quote from a 1996 study by the National Academy of Sciences to the effect that “the excess cost for an S&T [separation and transmutation] disposal system...easily could be more than $100 billion.” But the report included an important caveat right before the passage they quoted: “Assuming the feasibility of pyroprocessing of spent LWR [light-water reactor] fuel, the design information for a commercial-scale reprocessing facility needed to make cost estimates is not available.” Apparently the committee was estimating the cost of a separation and transmutation disposal system other than one involving pyroprocessing, so a higher cost for such a system cannot be assumed at this time.

The energy and dollars needed to implement large-scale deployment of MOX recycle technology would be better spent on wrapping up the development of fast reactors and their fuel cycle, thus achieving ultimate closure of the fuel cycle, an assured energy supply in perpetuity, removal of plutonium from commerce, proliferation-resistant nuclear energy, and optimal utilization of the Yucca Mountain repository.


Gerald E. Marsh is a physicist, retired from Argonne National Laboratory. He was a consultant to the Department of Defense on strategic nuclear technology and policy in the Reagan, Bush, and Clinton administrations and served with the U.S. START delegation in Geneva. George S. Stanford is a physicist, retired from Argonne National Laboratory. He is co-author of Nuclear Shadowboxing: Contemporary Threats From Cold-War Weaponry (2004).

Steve Fetter and Frank von Hippel Respond:

We are gratified that Gerald Marsh and George Stanford agree that it makes no sense to use existing commercialized reprocessing technologies to separate plutonium for recycle in light-water reactors. This would be more expensive, present much greater proliferation risks, and have no waste-disposal advantages over the direct disposal of spent fuel. This is an important conclusion because this is the only approach to reprocessing and recycling that could be deployed in the near term.

The technologies that Marsh and Stanford advocate—fast reactors with pyrometallurgical separation and recycling of the minor transuranic isotopes in addition to plutonium—are not commercially proven. Past failed attempts, in which tens of billions of dollars have been spent in efforts to commercialize fast reactors in France, Germany, Japan, Russia, the United Kingdom, and the United States, produced reactors with high costs, questionable safety, and poor reliability.

The technical barriers to full transuranic recycle in fast reactors may be overcome in time, but the economic barriers to their adoption are likely to remain for the foreseeable future. Marsh and Stanford are wrong when they say “[t]he expansion of nuclear power will necessitate the processing of reactor fuel.” Fast reactors can indeed make far more efficient use of uranium, but even with inefficient light-water reactors, the cost of uranium currently constitutes less than 2 percent of the price of nuclear-generated electricity. In a recent article in Nuclear Technology, one of us [Steve Fetter] has estimated that the price of uranium would have to grow by a factor of five to 10 in order to make full transuranic recycling in fast reactors cost effective. There is enough lower-cost uranium to sustain a substantial expansion of nuclear power using current once-through technologies for at least 50 years and probably much longer. By that time, we should have a much better sense of the longer-term role of fission power among our energy options. There is no urgency to develop and deploy fast reactors.

The waste-disposal advantages of full transuranic recycle cited by Marsh and Stanford are overstated. The direct disposal of spent fuel is inexpensive: $0.001 per kilowatt-hour, or less than 2 percent of the cost of electricity. Fast reactors would greatly reduce (but not eliminate) required repository space only if all transuranics are separated and recycled until they are fissioned and if the long-lived fission products were also separated and stored on the surface for several centuries, thereby defeating the main safety advantages of storing spent fuel underground. Admittedly, there are political barriers to expanding geologic waste disposal, but it is by no means obvious that the political barriers to the widespread deployment of fast reactors and associated reprocessing and surface waste-storage facilities would be substantially smaller.

They also exaggerate the potential nonproliferation benefits. One of us [Frank von Hippel] has completed a technical analysis of the nonproliferation aspects of the pyroprocessing technology that has been developed at Argonne National Laboratory. The analysis, soon to be published in Science and Global Security, indicates that the proliferation benefits claimed by Marsh and Stanford are quite short-lived. Unless spent fuel is pyroprocessed and recycled within two years after discharge from the reactor, the penetrating radiation emitted by the minor transuranics and those fission products that remain with the plutonium would not make it so dangerous to handle that it would be self-protecting by the International Atomic Energy Agency’s standards. This exception is irrelevant to the current debate over the reprocessing of U.S. spent fuel, which is on average already about 20 years old.

Moreover, Marsh and Stanford are wrong when they argue that the heat generated by the minor transuranics that remain mixed with plutonium make it unusable in a nuclear weapon. Indeed, the same analysis indicates that this mixture could even be used in a nuclear weapon like that dropped on Nagasaki. In any case, because the radiation dose rate from the mixture is relatively low, the plutonium could easily be chemically separated from the minor transuranics in a glove box.

In summary, despite the continuing enthusiasm of Marsh, Stanford, and some of their Argonne colleagues for the long-term possibilities of fast-neutron reactors and pyroprocessing, the promotion of those technologies is a diversion from the nearer-term issue we analyzed. Our article focused on the proposal recently agreed to in the November 2005 House-Senate conference on the energy and water appropriations bill that calls for the secretary of energy to submit a detailed plan for recycling by March 31, 2006, with “construction of one or more integrated spent fuel recycling facilities” to begin in fiscal year 2010.

As explained in our article, interim spent-fuel storage would be much less costly and less undermining of U.S. nonproliferation policy. With interim storage, any potential future energy value of the spent fuel will be preserved. There is much more time available to debate the long-term future of nuclear power than there is to strengthen the nonproliferation regime and dispose of the huge quantities of already separated nuclear weapons materials.

Steve Fetter is a professor and dean of the School of Public Policy at the University of Maryland. Frank N. von Hippel is a professor of public and international affairs at Princeton University.