For roughly a quarter century there has been a hiatus in nuclear-plant construction in Europe and North America. Now new plants are being built in France, Finland, and Russia, and new reactor proposals are gathering steam in the United States, the United Kingdom, and Canada. But to undergo a true resurgence—which many analysts argue is necessary to help reduce global greenhouse gas emissions—the nuclear power industry needs a coherent plan for dealing with its reactors' radioactive and toxic leftovers.
Burying the waste is a slow, politically painful process that leaves much to be desired. The long-planned U.S. repository under Yucca Mountain in Nevada has been immensely controversial. Yet if built as currently planned, it may be too small when it finally opens to accommodate all the high-level waste that has piled up in the country during half a century of commercial nuclear energy.
Lately, nuclear advocates, particularly in the United States, say they've found a better solution, or at least a path to one. It's based on the recycling and reuse of spent nuclear fuel, known as fuel reprocessing in the industry's jargon. Reprocessing breaks down fuel chemically, recovering fissionable material for use in new fuels. Thus, there is less highly radioactive material that needs to be sealed in caskets, buried deep underground, or otherwise permanently isolated from humankind.
"If we do reprocessing and recycle, we can increase the capacity of Yucca Mountain 100-fold," says Phillip Finck, a nuclear engineer at Argonne National Laboratory, in Illinois. Suddenly, instead of being crammed full on its opening day, Yucca Mountain would be able to handle everything the industry could throw at it until 2050 or beyond, staving off searches for additional Yucca Mountains.
As it happens, there's an ideal test case with which to evaluate that enticing proposition: France, which never backed away from nuclear energy and which has long relied on reprocessing as the linchpin of its power reactor fuel system.
The French experience clearly does show that reprocessing need not be the dangerous mess that other countries, including the United States, have made of it [see photo, "Blue Glow of Success"]. The U.S. military used reprocessing for several decades to separate plutonium from spent fuels, providing fissionable material for bombs. The result was widespread contamination—which has been in some cases irremediable—in the central Washington desert and the South Carolina coastal plain.
France, in contrast, now reprocesses well over 1000 metric tons of spent fuel every year without incident at the La Hague chemical complex, at the head of Normandy's wind-blasted Cotentin peninsula. La Hague receives all the spent fuel rods from France's 59 reactors. The sprawling facility, operated by the state-controlled nuclear giant Areva, has racked up a good, if not unblemished, environmental record.
The United States now claims to have a way of eliminating reprocessing's other major liability: the risk of spreading a supply of raw materials for bomb making. The United States officially banned reprocessing of spent fuel for power reactors in 1977, during the administration of President Jimmy Carter, who feared that proliferation of reprocessing technology would make it too easy for wayward nations or even terrorist groups to obtain the raw material for bombs. But in recent years, the U.S. Department of Energy engineers, including Finck, have developed an approach that they claim is more resistant to terrorist misuse, thereby mitigating concerns about nuclear security and proliferation. The result is that, three decades later, pressure is mounting for another look at reprocessing. The U.S. government is already supplying recycled fuels to one commercial reactor and planning tests of new proliferation-resistant reprocessing technologies.
Nevertheless, although it may be safe to proceed with reprocessing, France's experience suggests that reprocessing as done now is not ready to catalyze a full-blown nuclear renaissance. The problem in a nutshell is that without breeder reactors, which can break down the most long-lived elements in nuclear waste, reprocessing comes nowhere near achieving Finck's 100-fold reduction in that waste.
France's engineers tried harder than those in any other country to build and run breeder reactors reliably at a commercial scale, but ultimately they failed. The result is that even in France—the best real-world model of what reprocessing can accomplish—the technology remains a tantalizing but only partial solution to the problem of high-level nuclear waste.
Reprocessing got its start in the early 1940s, when Manhattan Project scientists sought a way to isolate pure plutonium. According to Richard Rhodes, author of The Making of the Atomic Bomb (Simon & Schuster, 1986), the chemist Glenn Seaborg, the discoverer of plutonium, came up with the basic concept. A carrier molecule grabs onto plutonium that's in a particular chemical state. That allows the carrier and the plutonium to be separated from the rest of the spent fuel. Further chemistry releases the carrier, leaving a solution of nearly pure plutonium.
It was a risky endeavor from the start because of the volatile, intensely radioactive materials involved. When it was scaled up at the Hanford Nuclear Reservation in Washington state to obtain the quantities of plutonium needed for bombs, immense concrete bunkers were built to house the operations [see "The Atomic Fortress That Time Forgot," IEEE Spectrum, April 2006]. The workers called them Queen Marys, after the British ocean liner, the world's biggest at the time. Inside, all the processing steps were done entirely by remote control, with technicians peering through thick windows at the machinery that moved materials through the chemical tanks. It was all part of what Bertrand Goldschmidt, an eminent French chemist who worked with Seaborg, called "the astonishing American creation in three years"—a network of laboratories and factories equivalent in size to the whole U.S. auto industry.
France's Commissariat à l'Énergie Atomique (CEA), a government organization, commissioned its first reprocessing plant in 1958 at Marcoule, in the south, to supply weapons-grade plutonium for the country's nascent atomic bomb program. It added an initial reprocessing unit at La Hague for the same purpose in the early 1960s. The equipment running today, however, dates mostly to a massive upgrade and expansion begun in the 1970s and 1980s. France cut a deal with five countries—Belgium, Germany, Japan, the Netherlands, and Switzerland—to finance the modernization of La Hague. In exchange, France agreed to reprocess those countries' spent fuel and return their separated plutonium, so as to reduce high-level waste volumes and provide additional fresh nuclear fuel. Today, the Areva Group, a spin-off of the CEA, runs La Hague as well as other French fuel-cycle installations and builds reactors via a subsidiary it co-owns with Siemens.
Even some of the nuclear industry's most tenacious opponents acknowledge that the result is a technical marvel. The leader of Greenpeace France's antinuclear program, Yannick Rousselet, says he no longer cites technical challenges in his criticism of Areva. "In the past," Rousselet says, "the antinuclear movement tried to say that they would not succeed with reprocessing. But they succeeded. To be honest, at least in terms of the technical aspects, it works."
Activists such as Rousselet had reason to doubt La Hague's chemistry, essentially the same as the separation process developed by the Manhattan Project. It has proved an ecological, occupational, and humanitarian disaster nearly everywhere else. Spills and explosions at reprocessing plants in the United States, Russia, and Britain have polluted rivers and contaminated hundreds of thousands of acres. Britain's Sellafield reprocessing complex, on England's Cumbrian coast, was shuttered in April 2005 after safety authorities discovered that 83 cubic meters of highly radioactive liquids had spilled during a period of nine months.
La Hague, in contrast, has never had a serious accident or spill. It does intentionally release relatively small amounts of radioactive substances into the air and water of the adjacent English Channel, whose strong currents were a key attraction of the La Hague site—behavior that Rousselet calls irresponsible and unwarranted. But the amounts released are below licensed levels and are dropping.
Eric Blanc, the marine engineer turned chemical plant operator who serves as La Hague's deputy director, tells the growing stream of visiting U.S. politicos and utility executives that La Hague's neighbors experience an annual radiation dose below 0.02 millisieverts—roughly equivalent to the dose of solar radiation the visitors receive on their transatlantic flights. La Hague's 5000 workers absorb less radiation than they would if they were employed at a nuclear power plant.
LA Hague takes exposure seriously, nevertheless. Inside the plant, there's a bit of the atmosphere of a James Bond movie. Protection suits and respirators hang on the walls. Scores of workers in white jumpsuits sit at computer screens in a central control room, while others control radiation-resistant robots or dexterous telemanipulators to guide, clean, or repair the equipment. The robots are in the thick of the action, and the danger lies safely isolated behind walls and leaded-glass windows 1 to 2 meters thick in workshops that have not seen a human in two decades of heavy-industrial operation.
Reprocessing at La Hague takes place in two independent but interconnected lines. At the front end of each line, robotic assemblies lift spent fuel-rod bundles weighing 500 kilograms from armored shipping casks and suspend them in 9-meter-deep pools of water. The fuel bundles are at 300 °C; after cooling for four to five years, the fuel elements are fed into the plant's processing workshops to be chewed up, dissolved in nitric acid, and run through a series of chemical separation baths. The chemistry is fundamentally the 63-year-old Purex process developed in the Manhattan Project—Purex stands for "plutonium-uranium extraction"—but Areva says the separation equipment employed is more compact than its predecessors and generates less waste.
The major products of the separation are uranium and plutonium. The former, consisting of the isotopes U-235 and U-238, constitutes 95 percent of the spent fuel. The plutonium yield is just a little more than 1 percent. Most of the uranium is shipped to an Areva plant in southern France and, at the moment, stockpiled. Some analysts predict that uranium prices will eventually justify more reuse of La Hague's uranium; but for now, utilities find it cheaper to use fuel freshly made from uranium ores and enriched to the precise isotopic composition they need. As for the plutonium, it is shipped across France to the Rhône Valley, where Areva's Marcoule fuel plant blends it with uranium and fabricates it into fuel for French reactors.
The final step in the process encapsulates the high-level waste, which consists mainly of acids and solvents from the Purex process plus dangerous, extremely radioactive leftovers from the spent fuel, including isotopes of curium, cesium, and iodine. This step is called vitrification. Technicians operating remote manipulators drop the toxic blend into a bath of borosilicate glass heated to 1150 °C, then dole out the molten mix into 180-liter stainless-steel canisters. Think of a huge glass paperweight with radioactive matter inside instead of colored swirls. But this particular glass is not fragile, Blanc explains. That's the point: the glass is supposed to immobilize the isotopes, isolating them from the environment, like bugs in amber, for thousands of years.
Once processed, two bundles totaling 528 fuel rods yield one vitrification canister 1.3 meters tall and a bit less than half a meter in diameter, plus another steel canister of similar size holding the compacted metal fuel rods. Even the largest of France's reactors, which can produce 1300 megawatts, generate just 20 canisters of high-level waste per year. According to Areva, it's about a factor of 10 reduction in the mass of highly radioactive waste needing to be stored under the most stringent conditions, and a four- or fivefold reduction in volume relative to leaving a plant's spent fuel unseparated [see flowchart, " The French Nuclear System"].
Despite its record of technical success, La Hague's business lost much of its shine during the past decade. By the mid-1990s, France's European partners were rethinking the wisdom of their investment in La Hague and, one by one, stopped shipping their spent fuel. From its 1997 to 1998 peak of 1700 metric tons per year, La Hague's throughput sharply decreased by 2003 to an average of 1100 metric tons per year. In part, France's partners were responding to grassroots concerns about the security of spent fuel and plutonium shipments [see sidebar, "The Terrorist Threat"]. But the ultimate cause for the slump traces back to the demise of the next-generation reactors designed to consume La Hague's plutonium, the so-called fast breeders.
All reactors get their heat from bundles of rods filled with a fissile fuel. The rods are inserted into a core in close proximity to each other, enabling neutrons radiating from the fuel in each rod to split heavy atoms of uranium or plutonium in neighboring rods, thereby generating more neutrons, which split more atoms, and so on. In most conventional power reactors, water or graphite is employed as a moderator to slow down the neutrons, thus rendering them more likely to be absorbed by U-235 atoms, knocking out more neutrons. That is necessary because the concentration of fissionable material in the fuel is low, just a few percent. In contrast, breeder reactor fuel contains a high fraction of fissionable material, so that a moderator is not required.
There is an additional potential advantage to the breeder reactor. By surrounding the fuel rods in its core with a jacket of U‑238, which is not fissionable by slow neutrons, the reactor can produce power and simultaneously "breed" new plutonium faster than the plutonium in the fuel rods is consumed. The U‑238 atoms capture neutrons to form fissile plutonium 239.
The reason for expanding La Hague in the 1980s was to produce a first load of plutonium fuel for what was to be a fleet of breeder reactors. Energy analysts, alarmed by the oil-supply manipulations of the 1970s, had predicted a rush into nuclear power that would exhaust uranium reserves in a matter of decades. "We were projecting that by 2010 nothing but fast [breeder] reactors would be built," recalls one such analyst, Evelyne Bertel, an expert in nuclear fuel cycles at the Organisation for Economic Co‑operation and Development's Nuclear Energy Agency, in Paris.
The United States and the Soviet Union both mounted major efforts to develop breeder reactors during the 1950s and 1960s. But it fell to France, after Carter took the United States out of the reprocessing and breeding game, to design and build the first commercial prototype.
In 1972, a consortium of companies led by the French utility Electricité de France (EDF) started work on the Superphénix. There were countless challenges. Above all was keeping the breeder's densely packed core from overheating, which could cause the fuel to melt and possibly even explode. Because the heat flux is so high in a breeder and absorption of neutrons by a moderator is undesirable, reactor designers faced a limited choice of coolants. In practice, almost all breeder designers have opted for liquid metals that are notoriously hard to handle. Liquid sodium, used in the Superphénix, is extremely corrosive and ignites explosively on contact with oxygen or water.
Starting in the mid-1980s, the Superphénix suffered a series of sodium leaks. Meanwhile the nuclear industry peaked and uranium prices crashed, eliminating the imperative to switch to plutonium fuel. The reactor went through several shutdowns and restarts before the French government finally pulled the plug for good in 1998. By then the reactor had run just 174 days at its full 1250-MW design capacity. A French government investigation in 2000 estimated that the project had cost about €9 billion (US $11.8 billion).
French industry players often blame politics for the Superphénix debacle. François Mitterrand, then president, held power through a coalition with France's staunchly antinuclear Green Party. However, the technical problems are undeniable. "The experience of Superphénix demonstrated that France built a nonmature technology," says Bertel.
With breeder reactors out of the picture for the foreseeable future, France tried to find a new role for La Hague's plutonium. The solution was to re-engineer Areva's fuel assembly plant at Marcoule, originally designed to make fuel bundles for the Superphénix, to instead produce plutonium-enriched fuel elements for conventional reactors. By blending plutonium and depleted uranium, in a ratio of 8 percent to 92 percent, the plant created so-called mixed-oxide, or MOX, fuel, which can be substituted for enriched uranium fuel after just minor modifications to a conventional reactor. Today MOX fuel provides close to 10 percent of France's nuclear power generation and is also used in Belgium, Germany, Japan, and Switzerland.
The downside is that spent MOX fuel is even tougher to transport, store, and reprocess than regular used fuel. Spent MOX fuel contains four to five times as much plutonium, increasing the risk of unexpected nuclear chain reactions, called accidental criticalities, within reprocessing plants. Spent MOX is also three times as hot as spent uranium fuel, thanks to an accumulation of transuranic isotopes such as americium and curium, making it less fit for underground storage.
Therefore, according to a 2000 consensus report on reprocessing prepared for France's prime minister, spent MOX must cool for 150 years before it can go into an underground waste repository such as Yucca Mountain [see sidebar: "The Prickly Economics of Reprocessing"]. Meanwhile, spent MOX fuel is piling up quickly in La Hague's cooling ponds: the 543‑metric‑ton accumulation grows by 100 metric tons every year.
The bottom line is that burning MOX fuel makes economic sense only as the beginning of a larger process that ends with incineration in a breeder reactor, and no sense at all as an end in itself. Most of France's reprocessing customers, seeing little future for nuclear energy amid the antinuclear demonstrations of the 1980s and 1990s, accordingly saw no future for breeders either. In that context, Bertel says, pulling away from reprocessing and MOX fuel made perfect sense. As she puts it, "If you are stuck with the spent MOX fuel, why bother?"
The French government and EDF remain invested in the country's nuclear future and therefore classify La Hague's spent MOX as a strategic reserve of plutonium to jump-start future breeder reactors. This eternal hope is, in fact, an essential justification for France's fuel cycle. Japan shares France's vision and built its own reprocessing plant using Areva's designs, which started up last year; the plant is expected to eventually supply Japanese reactors with MOX fuel.
France and Japan suddenly look less isolated in their reprocessing strategy, thanks to U.S. President George W. Bush. Early last year, Bush singled out France's nuclear program for a rare bit of cross-Atlantic praise, telling the American people in a Saturday radio chat that reprocessing will "allow us to produce more energy, while dramatically reducing the amount of nuclear waste." Surprisingly, Bush has endorsed reprocessing as not only a means of handling domestic nuclear waste but as a bold response to proliferation as well.
Turning a conventional argument on its head, Bush is saying that the risk of additional countries' using reprocessing to arm nuclear weapons can be lower, not greater, if the United States reprocesses. Under his proposed Global Nuclear Energy Partnership (GNEP), nations with "secure, advanced nuclear capabilities" would guarantee a steady supply of nuclear fuel to non-nuclear-weapons countries that agree to return the resulting spent fuel and the plutonium within for reprocessing, forgoing reprocessing plants of their own.
But many proliferation experts worry that Bush's plan could backfire. It's not clear that many countries will agree to forgo reprocessing, letting others do the work for them, while they themselves agree to take back the noxious wastes. If participation in GNEP is disappointing, the program could end up encouraging rather than impeding the spread of reprocessing technology—Areva, for one, is plainly interested in licensing its technology.
Whether or not GNEP attracts any takers, a movement toward reprocessing is already well established in the United States. U.S. utilities are getting their first taste of MOX fuel today, thanks to former President Bill Clinton, whose Energy Department in 1997 authorized the fabrication of surplus weapons-grade plutonium into MOX fuel for use in U.S. power plants. Clinton's DOE also awarded a contract to an Areva-led consortium to build a MOX fabrication plant at the DOE's Savannah River, S.C., site. While awaiting construction of the MOX plant—beset by lawsuits that have delayed its projected start date from 2009 to as late as 2015—Bush's first energy secretary, Spencer Abraham, gave Areva permission to produce a first load of MOX at Marcoule. The resulting fuel assemblies began producing power at Duke Power's Catawba, S.C., plant last year. (Abraham, by the way, has since signed on as chairman of Areva's U.S. subsidiary, Areva Enterprises.)
Since Bush's high-profile endorsement of reprocessing last year, nuclear players within and around the Energy Department have been lobbying Congress to support the next step toward full integration of plutonium into the U.S. nuclear industry: a reprocessing demonstration plant. The demo is needed to prove, at large scale, a reprocessing scheme called Urex+, developed at Argonne National Laboratory to be more proliferation-resistant than La Hague's. Urex+ coextracts plutonium together with other transuranic elements present in spent fuel. Such isotopes can be "burned" in a breeder reactor but would complicate the job of any would-be bomb maker, because they contaminate the explosive material somewhat.
The DOE's Spent Nuclear Fuel Recycling Program Plan, sent to Congress this past May, also calls for a demonstration of a breeder reactor fueled by Urex+. In fact, as with France's fuel cycle, the DOE plan is hard to defend unless several such breeder reactors are built. Without them, high-level transuranic waste would become a growing annoyance in the United States, much like the MOX bundles building up in La Hague's cooling ponds. Burton Richter, a Nobel laureate who leads the DOE's science panel on nuclear waste separations (and also serves on the board of Areva Enterprises), acknowledges that breeder reactors are DOE's endgame. "Everybody is in agreement that the right system ultimately results in multiple recycles in fast [breeder] reactors, so that's where things are going," Richter says.
With visions of nuclear electricity "too cheap to meter" long gone, the case for breeder reactors has shifted from creation of new fuels to management of spent fuels. Without breeder reactors, the case for reprocessing is less than compelling. Considered in isolation, the economic arguments for and against reprocessing are a wash. Most of the arguments concerning security and terrorism, too, seem moot. But until or unless breeder reactors are commercialized that can truly burn up all the residual fissile material found in spent fuels, reprocessing will simply concentrate high-level waste in a form that's hotter and harder to handle, exchanging one nuclear waste headache for another.
About the Author
Contributing Editor Peter Fairley has reported for IEEE Spectrum from Bolivia, Beijing, and Paris.
To Probe Further
A recent report to address recycling of nuclear fuels, critically, is "Managing Spent Fuels in the United States: The Illogic of Reprocessing," by Frank von Hippel. It is also available online at http://www.fissilematerials.org. "Economic Forecast Study of the Nuclear Power Option," a report to France's Prime Minister on the economics of reprocessing, was published in July 2000: http://fire.pppl.gov/eu_fr_fission_plan.pdf.
MIT's 2003 study, "The Future of Nuclear Power," is at http://web.mit.edu/nuclearpower.
Greenpeace France's "Stop Plutonium" Web site is http://www.greenpeace.fr/stop-plutonium/en.
The U.S. Department of Energy sent a Recycling Program Plan to Congress in May 2006: http://www.gnep.energy.gov/pdfs/snfRecyclingProgramPlanMay2006.pdf .
Areva's La Hague Web site is http://www.cogemalahague.com.