POSTED 28 FEBRUARY 2008
Reframing reprocessing: Miracle of recycling, or nightmare of proliferation?
Long before Americans were setting their bottles and cans on the curb for recycling, nuclear folks were thinking about recycling nuclear fuel. Recycling, AKA "reprocessing," can
Reduce the radioactivity and/or mass of spent fuel;
Produce more energy from each ton of uranium mined; and
"Close the fuel cycle" by reducing environmental impacts during fuel production and disposal.
Photo by J. Sutton-Hibbert, Greenpeace
At least, that's the theory. The reality of reprocessing is more contested than a Yankees-Red Sox Pennant duel, and the process is a bit more complicated than melting aluminum cans into new cans for Cherry Toothrot TM. Yet while reprocessing is controversial in the United States, it's common in France, the United Kingdom, Russia and now Japan.
Here's our quickie reprocessing primer: Robots chop up the hot, highly radioactive fuel rods, dissolve the chunks in acid, and separate the plutonium and uranium from the fission products (which block chain reactions). The uranium and plutonium are then blended into new fuel.
Thirty years after the United States rejected reprocessing of civilian nuclear waste, the DOE is reinvestigating reprocessing through the Global Nuclear Energy Partnership, initiated in 2006. GNEP offered this deal to other nations: If you want to use nuclear electricity, the United States will supply the fuel -- if you promise to send your waste back to trusty Uncle Sam for reprocessing. Twenty-one nations have signed on to that program, which also intends to design smaller, safer reactors for developing countries.
Critics charged that GNEP's emphasis on reprocessing marked a dangerous and expensive policy about-face. GNEP "undermines U.S. nonproliferation policy, would cost taxpayers $100 billion or more, and ... [would] not solve the nuclear waste problem," wrote the Union of Concerned Scientists and 39 other groups last fall.
Also last fall, a National Research Council report recommended rejecting GNEP's reprocessing research regime, although it did favor more restricted research on recycling. (The original GNEP proposal had included generous funding to build GNEP's infrastructure, but Congress scotched that part.)
Gregory Choppin, a professor of chemistry at Florida State University who has a long acquaintance with radiation chemistry says efficiency is a key argument for reprocessing, which extracts more energy from the uranium fuel, and therefore reduces the need to mine uranium. "If we go into reprocessing to recover the 99.5 percent of unburned uranium, and recycle it, we would not have to do any more uranium mining for 400 years," says Choppin. "That would be a tremendous advantage because uranium mining is very dangerous," especially in terms of lung disease, including cancer.
The coming nuclear boom has skyrocketed the price of uranium, but the Navajo Nation is still reeling from the last uranium boom, says Doug Brugge, associate professor of public health at Tufts University. Brugge says the "federal government has given compensation to over 6,000 uranium miners, millers and other workers" who suffered lung disease. "The government obviously has pretty stringent standards for compensation, so that's probably a low estimate, but ... that's a lot of people who died, or were made ill enough to qualify." In 2005, the Navajo Nation banned uranium mining, Brugge adds. "Their experience with uranium was so devastating that it overwhelms any financial incentives."
But could reprocessing also reduce the burden of finding safe storage for spent fuel? Yes, says Choppin. "You take out the plutonium, uranium, and probably some neptunium, which decays into plutonium, and keep them aside for further burning... so you not only destroy the plutonium and uranium 235, but you also get a lot of energy out."
However, the extent of reduction is open to debate. According to Michael Corradini, a professor of engineering physics at the University of Wisconsin-Madison, "You don't reduce the radioactivity that goes into the ground, you do reduce the volume, so ... you still have to dispose of the radioactive waste that was caused by the fission. That solid, compact material still has to be buried."
Dig this crazy process?
Reprocessing would be a mixed benefit, says John Ahearn, a former chairman of the Nuclear Regulatory Commission and director emeritus of Sigma Xi, the scientific research society. "It's not a permanent solution, does not reduce the heat load at all, because it does not get rid of the real heat-generating material [the fast-decaying fission products]. It does reduce the volume and mass, because you have pulled out the uranium, which is a large contribution, and the plutonium, which is one of the problems."
Ahearn adds that the viability of reprocessing depends "on whether you can separate all the actinides [the heavy elements, including uranium and plutonium], and can re-burn them. These are all technology issues that not been resolved."
Ahearn says reprocessing could reduce the needed volume of the repository by 30 percent, which "would go a long way toward resolving the issue of whether there is enough space in Yucca Mountain." Still, he says the technical questions about reprocessing would need 10 to 20 years of further study, so even if reprocessing proves helpful, it will not help in the short term.
Some observers take a much dimmer view of reprocessing, just as they did when the issue last surfaced 30 years ago. Reprocessing is "an incredibly complicated process, and it creates a liquid high-level waste stream," says Brice Smith, an assistant professor of physics at the State University of New York at Cortland.
Liquids are inherently tougher to contain than solids, and he says these wastes would need to be cast into glass or ceramic logs before going to underground storage. That process "has proven to be a significant challenge" at federal nuclear sites in Washington State, Idaho and South Carolina, he adds. "This liquid reprocessing waste would be very similar in a lot of respects to what we had left over from nuclear weapons, and it's very expensive" to handle.
Reprocessing of military waste does have a nasty environmental history: Huge tanks of radwaste at federal nuclear sites have awaited safe disposal for as much as half a century. According to Robert Alvarez, a nuclear policy specialist at the Institute of Policy Studies, less than 1 percent of defense reprocessing wastes have been stabilized, despite the spending of billions of dollars on the effort in Washington State and South Carolina. The rest remains in tanks with varying degrees of integrity.
Alvarez, who was a senior policy advisor in the DOE from 1993 to 1999, says GNEP is unlikely to survive scrutiny. "All this was flying around at the level of magical thinking, because no-one has taken a hard look" at the implications. For example, GNEP proposed to remove the fission products strontium and cesium from the spent fuel, Alvarez says. "No one has done this before, the amount of radioactivity is breathtaking; it's billions of curies. This is fantastically hot." (One curie of radioactive material emits the same radiation as one gram of radium 226: 37 billion radioactive disintegrations per second.)
This waste would need to be stored above ground for 100 years, before being diluted and placed in underground storage.
Even if, as GNEP plans, only 1 percent of elements heavier than uranium (including plutonium, americium and curium) end up in the waste, Alvarez sees danger. "That turns out to be many times more curies than was generated by the nuclear arms race."
Overall, GNEP seems rather helter-skelter, Alvarez charges. "These guys did not have any kind of plan, no estimate of the waste volume, concentration, how to manage it, dispose of it, and how much it is all going to cost."
But reprocessing is a big lure for federal nuclear labs and some in Congress, Alvarez says. "Politicians keep drinking the Kool Aid of recycling ...without understanding that this is the same thing we had to deal with 30 years ago" when India got the bomb through reprocessing. Reprocessing "is not recycling. It is a gateway technology for the manufacture of nuclear weapons, and it generates a large amount of waste which will make the [waste] problem worse."
As Alvarez indicates, during reprocessing, plutonium is separated from spent fuel, and it can then become a primary fuel for nuclear weapons. The military reactors built during and after World War II were designed to make plutonium for fission (atomic) and fusion (hydrogen) bombs.
When civilian nuclear power arrived in the 1950s, reprocessing was suggested as a way to stretch the uranium supply. Then in 1974, India tested a nuclear bomb made from reprocessed research-reactor fuel, and Presidents Ford and Carter rejected reprocessing in the civilian nuclear realm.
Although opponents warn that reprocessing does the dangerous plutonium separation for nuclear terrorists and states that want the bomb, observers are not unanimous about the dangers of reprocessing. GNEP, for example, has proposed to find a technical solution that would block proliferation during reprocessing. One option is to leave high-intensity isotopes in the newly made fuel, to make it literally "too hot to handle." "Reprocessing is more of a proliferation risk than direct disposal," concedes Ahearn, but he thinks it possible to safeguard a reprocessing plant against proliferation. "There are reprocessing plants in Europe that have operated for decades, Japan is about to open a huge new one. I don't know any case where the plutonium from any of those plants has been stolen."
Choppin says enhanced international cooperation could address proliferation concerns. "The IAEA [International Atomic Energy Agency] already does a lot of international inspection of nuclear energy processes. If the IAEA is allowed to supervise, monitor the reprocessing, they could keep track of proliferation."
Choppin says anti-proliferation efforts may benefit from a reorganization of the nuclear infrastructure. "I like a proposal by South Africa to build four or five reactors around a reprocessing plant" and reduce vulnerable shipments of nuclear material. "This has been suggested in Europe, to localize the reactors, so ... all the dangerous stuff is right there, it's easy to put the safeguards on and secure" the plutonium.
Reprocessing -- no silver bullet
Although reprocessing remains highly controversial, our experts agreed that at some point, radioactive material that can supply no further energy will need burial to deter proliferation and environmental contamination. "Even if you do reprocessing, you still end up with some waste," says Ahearn.
In France, and in the other countries that are reprocessing, "They cycle back the long-lived material, but still have to bury something," says nuclear engineer Michael Corradini. "The French are reprocessing, taking 99 percent of the mass and putting it back into plants to reuse the uranium, burn down the plutonium, but they are still building up more waste -- you can change the nature of it, but you can't get rid of it."
Recycling builds up a waste stream containing short-lived (and intensely radioactive) isotopes like strontium 90 and cesium 137, while making electricity from the long-lived isotopes of plutonium and other transuranics, Corradini adds. "My message is that you always have to bury something... There is no magic bullet. Eventually you will have a radioactive substance which has various times in which it decays, and you will have to put it in geological isolation."
Like Yucca Mountain. But will Yucca ever work?
Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive