Reprocessing spent nuclear fuel is not economically justified and will not relieve U.S. nuclear waste problems.
BY WILLIAM C. SAILOR
In response to growing concerns in the United States about proliferation of nuclear weapons, President Carter issued an executive order in 1977, suspending indefinitely the commercial reprocessing of used fuel removed from nuclear reactors. With the Nuclear Waste Policy Act of 1982, disposal of this spent fuel in repositories carved out of underground geological formations became U.S. national policy.
Although there have been amendments to the 1982 act, the initial date on which the U.S. Department of Energy would accept spent fuel for disposalJanuary 31, 1998has never been changed. That date has come and gone, of course, but DOE has yet to accept its first shipment of spent fuel. Profound political problems at all potential nuclear waste storage sites since 1982, along with technical and political problems at the Yucca Mountain site in Nevada since 1987, have effectively prevented DOE from meeting its schedule.1
This failure of the federal government to come even close to meeting its schedule, combined with fears of energy shortages, is taken by some to mean that reprocessing spent fuel should once again be considered an option.2 Such a conclusion, however, ignores studies showing that reprocessing would not relieve nuclear waste disposal problems nor improve the economics of nuclear power.
Indeed, many of the major reasons for President Carters decision to suspend reprocessing are as sound today as they ever were, and the circumstances supporting that decision are unlikely to change during the next several decades.
COSTS AND BENEFITS
In 1977, a group sponsored by the Ford Foundationthe Nuclear Energy Policy Study Groupreleased a report called "Nuclear Power Issues and Choices," which was the basis of President Carters decision to suspend the reprocessing of spent fuel.3
The Nuclear Energy Policy Study Group concluded that despite nuclear powers many problems, the light-water reactor would and should be a major source of electric power in the future. The group also concluded that the breeder reactor would be too expensive to compete in the market and that stockpiling plutonium for the breeder was therefore unnecessary.
Furthermore, recycling of plutonium offered no significant cost advantages for nuclear waste disposal. Under these circumstances, which have not changed since then, there is no economic incentive to reprocess spent fuel.
Estimates of the future availability and cost of uranium are central factors to deciding whether the United States should reprocess plutonium or build breeder reactors. Until the cost of uranium ore rises significantly, it is cheaper to produce low-enriched uranium from new ore than to separate plutonium from spent fuel. The study also noted that if uranium followed the example of other minerals, the higher costs accompanying increased demand would lead to profitable ways to exploit lower grade sources. This would result in much larger supplies of uranium than have been previously forecast.
Because of a great slowdown in new nuclear power plant construction activities during the 1980s, anticipated demand for uranium did not materialize, but new uranium ores of higher quality were discovered. As a result, during the past two decades, there has been no shortage of uranium and no increase in cost. In fact, there is such an oversupply of uranium that the cost todayabout $4.50 per kilogram ($10 per pound)is less than one tenth of the cost of uranium in inflation-adjusted dollars at the time of President Carters decision. It is difficult to identify any other basic material whose real cost has declined so precipitously. At present, many uranium mines have closed because they cannot compete at current prices, and there is a worldwide excess capacity of enrichment facilities to produce low-enriched uranium for standard light water reactors. In short, a genuine market for plutonium fuel is nonexistent.
A 1996 report, published by the Electric Power Research Institute (EPRI), shows that the market price of uranium must increase by at least a factor of five over its current price before plutonium becomes competitive with uranium in light-water reactors.4 The price requirement may be relaxed somewhat if reprocessed plutonium is used to fuel breeder reactors, in the unlikely event that a large number of them are built. Breeder reactors require large amounts of plutonium at startup.
The EPRI study concluded that the time for economically introducing the reprocessing and recycling of plutonium may occur within 50 years. It did not recommend that the United States slow its plans to bury spent fuel at Yucca Mountain, because adequate supplies of spent fuel would be available above ground for reprocessing in the future regardless of whether Yucca Mountain has been opened.
EPRIs findings offer a reasonable basis for continuing with the Yucca Mountain work and not reprocessing plutonium. Their analysis may have been too conservative, however. For example, the study seems to have ignored the effect that increased uranium prices would have on uranium exploration. Because a factor of five in the price of uranium is a significant increase, it stands to reason that a substantial amount of new exploration for uranium ore will be undertaken worldwide before the full factor of five is realized.
Reserve and resource estimates for minerals have a long record of being understated. Estimates of reserves typically originate with industry and reflect its view of what is marketable as well as what may prudently be characterized as reserves. Generally, as markets expand or as prices rise, an industry is motivated to look for, and tends to find, new reserves. This explains why reserve and resource estimates rise along with rising production. One should therefore keep an open mind regarding the potential for incremental discoveries and large surprises.
Additionally, EPRI assumed that the costs associated with mining uranium were fixed and no allocation was made for improved mining technology in the years ahead. The analysis they used for reprocessing technology, on the other hand, predicted that the costs would decrease with time. The comparison was not fair.
According to the EPRI study, the supply of uranium from seawater is extremely large but the cost of recovery is also extremely high: about $800 per kilogram ($1,800 per pound). Again, neglected in the analysis is how the advance of technology in the next 50 yearsespecially under conditions where the market price of uranium is dramatically increasingwould affect this cost. If the cost of obtaining uranium from seawater should become competitive, the price of all uranium would plateau or even decrease.5
Based on the above reasoning, the 50-year time estimate for the introduction of reprocessing is most likely premature. In fact, the cost of even an infinite delay in the introduction of reprocessing may be zero.
An equally important consideration is whether reprocessing can improve the long-term health consequences of nuclear waste disposal. A 1996 analysis by the National Academy of Sciences Committee on Separations Technology and Transmutation Systems compared the environmental effects of reprocessing to the environmental effects of burying spent fuel. The study found that there were no environmental reasons to abandon the policy of burying spent fuel.6
After long periods of time, the principal doses to humans from geological storage of nuclear wastes are likely to be mainly from the fission products technetium-99 and iodine-129, which are water soluble and therefore can move through groundwater. Recyclin g these two fission products, along with neptunium, could result in a small reduction in the amount of long-term risk to the public.
The solubility of neptunium is sensitive to its chemical environment, which makes it difficult to accurately predict the risk from this species if spent fuel is buried. When all error limits are put to their highest values for solubility, the resulting doses from neptunium-237 can be higher than doses from technetium-99 and iodine-129. The peak doses from neptunium-237 would tend to occur about a million years from now. If the effective solubility of neptunium turns out to be high, reprocessing spent fuel and recycling neptunium could have some health benefit.
To the extent that plutonium would replace uranium as reactor fuel, the amount of uranium that would need to be mined would be reduced, and the short-term radiation exposures from mining and milling would similarly decline. Although there would be a short-term increase in radiation exposure from reprocessing and other fuel-cycle activities that would not be present if spent fuel were buried, the population doses from these sources would be small.
If the radioisotopes of concern were separated from the spent fuel and packaged into specialized waste forms, reductions in long-term doses to the public could occur. Neptunium, technetium, and iodine could be separated by chemical means and formed into insoluble compounds. These compounds would be specially packaged in glass, ceramic, or other material. This technology is well within reach, but reprocessing of spent fuel for this purpose alone would be extremely expensive.7
Despite these considerations, the major conclusion from the National Academy of Sciences Committee on Separations Technology and Transmutation Systems study and from all credible prior studies is that the estimated long-term effects from any of these actions are extremely small compared to the cost.
According to the study, the elimination of long-term risk by reprocessing fuel under perfect conditions would amount to only 0.06 cancer fatalities per plant per year. This amount of reduction in risk has essentially no effect on the comparison of public health effects of nuclear power versus other forms of electrical power generation. Therefore the environmental argument in favor of nuclear energy would not improve in any meaningful way, even with a perfectly clean reprocessing technology.
The small size of the health benefit relative to cost, even from perfect reprocessing, is indicated by the following. If we assume $1 million per cancer avoided, this savings would be worth $60,000 per reactor-year. The cost of reprocessing, however, would be over $10 million per reactor-year, which is certainly not a good return on a public-health investment.
OBJECTIONS TO BURIAL
When Sir Walter Marshall headed Britains nuclear power program, he called a spent fuel repository a plutonium mine. He was referring to the idea that the fuel could be reexcavated and processed to recover the plutonium component for weapons in the future. Decades after storage in a repository, the radioactivity would be low enough to permit mining and reprocessing to separate the plutonium. Moreover, the plutonium would have lost some of its shorter half-life, heavier isotopes, making it a somewhat more attractive weapons material.
For a nation wanting to construct a large number of warheads in a short period of time, reexcavating a nuclear repository may be a cheaper, faster route than creating a new plutonium-production infrastructure. Repositories or storage facilities should therefore be located in only a few countriesones that are already weapon states. The fuel would still be under international safeguards at all times in the future. If someday there should be no separated plutonium or mixed uranium oxide and plutonium oxide (mixed oxide) fuel available in large quantity above ground, old spent commercial fuel stored above ground would then be the relatively fastest route to new large-scale weapon production, followed by buried old spent fuel. Until this is the situation, however, these paths should not be considered a significant contributor to the overall proliferation threat.
To the extent there is merit to this argument, it does not necessarily lead to a reprocessing imperative. Above-ground storage of spent fuel at interim storage facilities for the next several decades is the most cost-effective alternative to direct burial.
Another recent claim was that fissile material should not be buried underground because of the possibility of explosion.8 Reviews of the theory during the past few years, however, have concluded that the overall probability of such an occurrence is negligible and should be listed in the same category of risk with meteor strikes to the repository.9 The reason is that the probability of each of the major steps leading to such an occurrence is very small. The originators of the theory were never able to show how an initial supercritical configuration leading to a nuclear reaction would ever come to pass. It has further been concluded that if any supercriticality event were to occur, the energy release would be very small and would have no public health consequences.
Whether a nation constructs nuclear weapons is mainly driven by a combination of perceived international threat and domestic politics. Access to nuclear materials is a third consideration.
Reprocessing spent commercial nuclear fuel has not been used as a path to weapons. This is true for all the major weapons states, including the United States, which developed weapons capability through separate military programs. Therefore, reprocessing of commercial spent fuel cannot be said to cause nuclear weapons proliferation among nations.
A possible exception to this is India. For years before its May 1998 nuclear weapons tests, the government of India stockpiled plutonium to maintain the option to build weapons. It is believed that all of Indias weapon plutonium has originated in special-purpose reactors and that it has not used power reactors to build its stockpile. One of Indias special-purpose reactors and one of the reprocessing facilities it used, however, were originally obtained from other countries with the agreement that the facilities were for peaceful purposes only.10
Indias rival, Pakistan, developed its nuclear arsenal through uranium enrichment, bypassing the need for plutonium altogether. South Africa did the same during the 1980s but has since dismantled its weapons.
It has long been feared, however, that clandestine diversion of plutonium from a commercial reprocessing stream could allow subnational or terrorist groups access to nuclear weapons. During the 1970s, many in the U.S. government believed that U.S. influence on the world nuclear power industry could curtail reprocessing and diminish this threat.
This was the main reason why President Carter decided to halt U.S. reprocessing. It has become clear after 20 years, however, that Carter misjudged the international response. The United States isolated itself from the other major players in nuclear power, many of which rejected the abandonment of the plutonium fuel cycle option.
A number of countries, including France, Japan, and Russia continue to pursue plutonium reprocessing and recycling today. These countries have invested in nuclear energy programs that include reprocessing and, in some cases, breeder reactors. France and Japan, in fact, have no other domestic energy resources. This seemingly uneconomic solution to their energy problems reflects their desire to maintain independence from Middle East oil supplies and the potential vulnerability to trade disruption. In France, nuclear energy represents a majority of electrical power production, and recycling of plutonium in power reactors is common. Japan is even more fuel-poor and is driven by a deep-rooted desire for energy self-sufficiency going back to its experience during the World War II blockade.
Just because these countries have stayed with reprocessing, however, does not mean the policy would be good for the United States. Moreover, Russias decision to stay with reprocessing may have dire consequences for world security during the next few decades.
With the end of the Cold War, the proliferation risks associated with the potential leakage of plutonium and highly enriched uranium from the Russian program are now of the highest importance. U.S. attempts to discourage Russias reprocessing of nuclear fuel have met with little success.
Although material shortages were common in the Soviet Union, there was apparently never any shortage of weapon-usable material. Current estimates of Russias nuclear-material inventory, which is distributed over 50 sites, are 1,100-1,300 tons of highly enriched uranium and 165 tons of weapons-grade plutonium. There are significant quantities of nuclear materials in the other post-Soviet states as well. The declared inventory tends to rise with time as more new caches of material are discovered. For instance, the declared inventory at one research institute in Ukraine grew from 15 to 75 kilograms (33 to 165 pounds) during 1996.
Increased presence of International Atomic Energy Agency inspectors in the former Soviet Union and U.S.-initiated safeguard measures are helping to decrease risk throughout the plutonium and uranium fuel cycles. Much work remains to be done, however. The Russian nuclear program continues to be driven by the remnants of its centrally planned economy, and its planners view plutonium and related infrastructure as an extremely valuable resource.
The majority of Russias leaders and citizens believe that an expanding nuclear energy program is necessary. There is no inertia to cease reprocessing of spent fuel even though Russia has a dramatic oversupply of nuclear fuels and not enough money to pay for continued operation of many of the existing nuclear power stations. Russians are also strongly in favor of using plutonium from dismantled nuclear weapons as fuel for their power reactors.
Mainly because of the need to act in unity in disarmament, the United States is planning to burn weapons-grade plutonium in reactors. The use of excess plutonium from eliminated nuclear weapons in commercial nuclear reactors is simply a good method of disposing of existing separated plutonium. After irradiation it will be no more accessible to theft or diversion than plutonium from normal spent fuel from commercial reactors. Plutonium is no longer considered a special proliferation threat once it has been burned in a reactor. It joins the hundreds of tons of plutonium in the nations commercial spent fuel inventory.
Evidence today suggests a slow but growing increase in the rate of diversion of proliferation-significant materials from the former Soviet Union. Several cases of illegal export of nuclear material have been confirmed, including the discovery of 560 grams of mixed oxides of uranium and plutonium on a Lufthansa Airlines flight from Moscow to Munich. The powder was probably meant for an experimental mixed-oxide-fuel reactor in Russia, but no final determination has been made of the source. In any case, security seems to be lacking in many of the smaller, research-related facilities and naval fuel facilities in Russia.
U.S. assistance to Russia through various government-to-government programs has contributed significantly to the safeguarding of Russias nuclear assets. The impact of this assistance can be increased by a truly cooperative relationship. Helping the Russians plug the leaks in their fuel cycle is an excellent means of creating a sense of a shared mission between the former Cold War rivals.
In this same spirit, buying tons of surplus plutonium from Russian stockpiles may be in our own security interests. The material could be made into mixed-oxide fuel for use in commercial reactors. Such an action would constitute a one-time, one-way transfer of weapons-grade material into a relatively harmless spent fuel, similar to the way we are buying $12 billion worth of highly enriched uranium from the Russians. And it would not involve reprocessing of any spent fuel.
TOWARD A MORE OPEN DEBATE
The role of nuclear power in the United States has declined from all of the projections that were being made 20 years ago. The market price of uranium has dropped precipitously and many new reserves have been found. Thus there is no economic incentive to reprocess spent nuclear fuel, and it is unlikely that an economic incentive to reprocess will appear for many decades, if ever.
Dry storage of spent nuclear fuel has been licensed by the Nuclear Regulatory Commission at many sites and has been usually implemented without excessive difficulty. Expansion of dry storage either at reactor sites or at interim storage facilities should continue until a national repository is ready to accept the spent fuel.
The policy against reprocessing does not damage the nuclear power industry. In fact, the introduction of a new and costly fuel cycle that provides no significant environmental or waste disposal benefits could do the industry only great damage. While no immediate prospect for investment in nuclear power plants exists, things could change. If nuclear energy should again become a viable option, uraniumnot more expensive fuelswill be the fuel of choice.
In a few decades, the nation will need new power plants to meet growing needs for electricity and to replace obsolete plants. When that time comes, let us hope that nuclear energy will be debated with open and honest expression, not with the emotional rancor that has so characterized the recent past.n
William C. Sailor is an analyst at Los Alamos National Laboratory, Los Alamos, New Mexico.11
1. The Yucca Mountain site is the Department of Energys proposed site for permanent burial of the nations high-level nuclear wastes.
2. Senator Pete Dominici, "A New Nuclear Paradigm," Nuclear News (December 1997), p. 26.
3. S.M. Keeny Jr. et al., Nuclear Power Issues and Choices: Report of the Nuclear Energy Policy Study Group (Cambridge, Massachusetts: Ballinger Publishing Company, 1977).
4. Electric Power Research Institute, A Review of the Economic Potential of Plutonium in Spent Nuclear Fuel, EPRI TR-106072 (February 1996).
5. R.L. Garwin, personal communication, March 11, 1998. He cites more recent Japanese and French estimates of seawater uranium costs of $300/kg and $80/kg, respectively.
6. "Nuclear Wastes: Technologies for Separations and Transmutation" (Washington: National Research Council, 1996).
7. T.H. Pigford et al., A Study of the Isolation System for Geological Disposal of Radioactive Wastes (Washington: National Academy Press, 1983).
8. C.D. Bowman and F. Venneri, "Underground Supercriticality from Plutonium and Other Fissile Material," Science and Global Security 5 (1996), pp. 279-302.
9. G.H. Canavan et al., "Comments on Nuclear Excursions and Criticality Issues," Los Alamos National Laboratory Unclassified Release, LA-UR-95-0851 (1995).
10. D. Albright, F. Berkhout, and W. Walker, Plutonium and Highly Enriched Uranium 1996 World Inventories, Capabilities and Policies (London: Oxford University Press, 1997).
11. The author is indebted to David Rossin of Stanford University; Per Peterson of the University of California, Berkeley; Ed Rodwell of EPRI; and Dick Garwin of IBM for their comments and conversations while this paper was in progress. The opinions expressed here are solely those of the author.