Energy

A New Vision for Nuclear Waste

Storing nuclear waste underground at Yucca Mountain for 100,000 years is a terrible idea. A better approach may be to buy some time–until new containment technologies mature.

When American Airlines Flight 11 flew at low altitude down the Hudson River valley on the morning of Sept. 11, 2001, its target was the north tower of the World Trade Center. But its impact is still being felt at a cluster of buildings it passed about five minutes before it reached lower Manhattan, at a nuclear-reactor complex called Indian Point in Buchanan, NY. Adjacent to the site’s two operating reactors are two buildings packed with highly radioactive spent-fuel rods, in pools of water 12 meters deep and tinged Ty-D-Bol blue by boron added to tamp down nuclear chain reactions. The soothing hum of the pumps that circulate the building’s warm, moist air – and, critically, keep the water cool – lends an atmosphere of industrial tranquility.

Without that cooling water, the fuel cladding might overheat, melt, catch fire, and release radiation. Whether the impact of a Boeing 767 like Flight 11 could drain one of the pools and disable backup water pumps, starting such a fire, is far from clear. Nevertheless, the threat of terrorism in general and the flyover of Flight 11 in particular have reignited the debate about why all of this dangerous fuel is still here – indeed, why all spent fuel produced at Indian Point in three decades is still here – and not at Yucca Mountain, the federal government’s burial spot near Las Vegas, where it was supposed to be shipped beginning six years ago.

Late this past summer, a construction project began at Indian Point that will allow the fuel to be pulled out of the pools. But it’s not going to Yucca. The government says Yucca won’t be ready until 2010. Executives in the nuclear industry say a more likely date is between 2015 and never. So instead of traveling to Nevada, Indian Point’s fuel is traveling about 100 meters, to a bluff overlooking the Hudson River. On a late-summer day this year, a backhoe tore out maple and black-walnut trees to make way for a concrete pad. Beginning next year, the first of a planned 72 six-meter-tall concrete-and-steel casks will be placed there, a configuration that adds storage capacity and thus allows the twin power plants to keep operating. Though they provide a hedge against a worst-case fuel-pool meltdown, these casks are merely another temporary solution. The fact that they’re needed at all represents the colossal failure of the U.S. Department of Energy’s Yucca plans and technology.

Yet as engineering and policy failures go, this one has a silver lining. Conventional thinking holds that Yucca’s problems must be solved quickly so that nuclear waste can be squirreled away safely and permanently, deep within a remote mountain. But here’s the twist: with nuclear waste, procrastination may actually pay. The construction of cask fields presents a chance to rethink the conventional. The passage of several decades while the waste sits in casks could be immensely helpful. A century would give the United States time to observe progress on waste storage in other countries. In the meantime, natural radioactive decay would make the waste cooler and thus easier to deal with. What’s more, technological advances over the next century might yield better long-term storage methods. “If it goes on for another 50 years, it doesn’t matter. It could go on for 100 or 200 years, and it’s probably for the better,” says Allison Macfarlane, a geologist at MIT and coeditor of a forthcoming book on Yucca. “We’ve got plenty of time to play with it.”

The government must now accept that its Yucca plan is a failure and that casks are the de facto solution. Indian Point’s cask pad will not be the first; about two dozen operating reactors have them already. Others are likely to soon join the list. And some casks – at Rowe, MA, Wiscasset, ME, Charlevoix, MI, and a site near Sacramento, CA – are nuclear orphans, having outlived their reactors. Each cask pad is roughly the size of a football field, floodlit, watched by motion sensors and closed-circuit TV, and surrounded by razor wire and armed guards. Given the homeland-security concern posed by nuclear-waste facilities, and the need to guard them individually, do we really want 60 of them – serving all 125 commercial reactors that have ever operated – to rise around the nation, many near population centers? If casks are the solution for the next generation or two, they should be put in one place.

Yucca is already on tenuous ground; in July a federal appeals court said that to open the mountain burial site, the government would have to show that it could contain waste for hundreds of thousands of years. Extensive scientific analyses by the Energy Department show it cannot. The court’s decision throws the whole question back to the U.S. Congress, which must now decide whether to proceed with Yucca at all. This presents an opportunity to align policy with physics and abandon the Yucca-or-bust dogma that has dominated the debate for nearly 20 years. Casks, centrally located, could make the high-level-waste problem a lot easier to solve and increase national security much sooner, too.

The Tunnel Vision

The federal fixation on Yucca Mountain now spans two decades. Beginning in the early 1980s, the government agreed to take waste from any nuclear utility that paid a tariff of a tenth of a cent per kilowatt-hour generated by its reactors. All the companies quickly signed up. But the selection of Yucca, 150 kilometers northwest of Las Vegas, was never driven by science. The site was chosen by that august group of geologists and physicists, the U.S. Congress. So far, the Energy Department has spent about $6 billion on development, including building an eight-kilometer, U-shaped tunnel through the mountain, in some places nearly 300 meters below the surface. It plans to spend at least $50 billion more to build dozens of side tunnels, package the waste in steel containers that look like the tanker portion of a gasoline truck, place the waste in the tunnels, and operate the site for 50 to 100 years before sealing it for eternity.

Problems have plagued Yucca since the beginning. In Senate debate, proponents stressed how dry it is. Yucca is, in fact, located in what is now a desert. But it turns out that the ground is moist. Even the 19 or so centimeters of rain the mountain gets each year is a major problem. Over time, moisture can corrode even the best alloys known to man. Corrosion would mean that rainwater percolating through the ground could carry radioactive materials with it and convey them to irrigation systems and drinking-water wells in the region, delivering substantial doses of radiation to unsuspecting people generations hence.

Heat is another problem. The shorter-lived radioactive isotopes in used fuel, principally cesium-137 and strontium-90, give a single fuel assembly, fresh out of the reactor, a heat output equal to that of about 20 handheld hair dryers. That’s why each power plant has an adjacent storage pool that circulates cooling water. Once the fuel was underground at Yucca, it would be hot enough to boil ground water into steam. Steam could corrode the containers or break up surrounding rock, raising uncertainty about secure burial. Spreading the waste out would dissipate the heat, but it would also greatly reduce Yucca’s storage capacity. Then there’s the problem of radioactive decay. High-energy particles can interact with surrounding materials, breaking them down or causing them to give off hydrogen, a gas that can explode or burn.

Early this year, researchers at Catholic University of America, hired by the state of Nevada, took samples of the kind of metal the Energy Department wants to use at Yucca and put them in some water mixed with the minerals present in the mountain. As a series of speakers lectured reporters on why Yucca was a bad idea, the researchers sautéed the metal over a burner. By the time the lectures were done, the samples had corroded, some of them all the way through. How faithfully the stunt reproduced the chemistry of Yucca Mountain is debatable. But clearly, Yucca is subject to serious doubts. “You have to think somewhere back in the premise structure of the whole thing, something was dreadfully wrong,” says Stewart Brand, a San Francisco-based consultant who once advised the Canadian government on what to do with its own waste.

Cooler Fuel

The argument against casks is that they are merely temporary, not meant to serve longer than perhaps 100 years, and that they are a kind of surrender, leaving this generation’s waste problem to a future generation to solve. Yet their impermanence is exactly what’s good about them. A century hence, spent reactor fuel will be cooler and more amenable to permanent disposal. In fact, within a few decades, the average fuel bundle’s heat output will be down to two or three hair dryers. After 150 years, only one-thirty-second of the cesium and strontium will remain. The remaining material can be buried closer together without boiling underground water. Reduced heat means reduced uncertainty.

Granted, spent fuel will be far from safe after such a relatively short period. Even after 100 years, it will still be so radioactive that a few minutes of direct exposure will be lethal. “It’s many, many, many thousands of years before it’s a no nevermind,” says Geoffrey Schwartz, the cask manager for Indian Point, which is owned by Entergy Nuclear. “But the spent fuel does become more benign as time goes by.”

The fuel could be more valuable, too. For decades, industry and government officials have recognized that “spent” reactor fuel contains a large amount of unused uranium, as well as another very good reactor fuel, plutonium, which is produced as a by-product of running the reactor. Both can be readily extracted, although right now the price of new uranium is so low, and the cost of extraction so high, that reprocessing spent fuel is not practical. And the political climate does not favor a technology that makes potential bomb fuel – plutonium – an item of international commerce. But things might be different in 100 years. For starters, the same fuel could be reprocessed much more easily, since the potentially valuable components will be in a matrix of material that is not so intensely radioactive.

And in 100 years, advances in reprocessing technology might make the economics compelling. The existing American technology dates from the Cold War and involves elaborate chemical steps that create vast quantities of liquid waste. But an alternative exists: electrometallurgical reprocessing. Though research into the technique has lagged of late because of the economic climate, the concept might be taken more seriously in the future. Electrodes could sort out the garbage (the atoms formed when uranium is split) from the usable uranium (the uranium-235 still available for fission and the uranium-238 that can be turned into plutonium in a reactor), in something like the way jewelers use electrometallurgy to apply silver plate. Resulting waste volumes would be far smaller.

Perhaps most importantly, in 100 years, energy supply anddemand might be very different. Reprocessed nuclear fuel might well become a critical part of the energy supply, if the world has run out of cheap oil and we decide that burning coal is too damaging to our atmosphere. If that happens, we might have 1,000 nuclear reactors. On the other hand, we might have no reactors, depending on the progress of alternate energy sources like solar and wind. At this point, it’s hard to tell, but we are not required to make the decision now; we can put the spent fuel in casks for 50 years and then decide if it is wheat or chaff.

There is a final, more practical reason that we might choose to take the plutonium out of spent fuel for reactor use: it makes the remainder easier to store. For the most part, what’s left will not be radioactive for nearly as long, and the sheer volume of material will be lower. Mark Deinert, a physicist at Cornell University, says reprocessing, like recycling, removes about half of the material from the waste, dramatically decreasing storage costs and effectively doubling the capacity of a facility like Yucca.

Betting on Better Storage

While nuclear waste would be easier to handle in 50 or 100 years, it would still require isolation for several hundred thousand years. But there is every reason to expect that storage technology will improve in the next century. When we decide to permanently dispose of the waste, either after reprocessing or without reprocessing, we may be smarter at metallurgy, geology, and geochemistry than we are now.

Today, the basic technology at Yucca is a stainless-steel material called alloy 22, covered with an umbrella of titanium – a “drip shield” against water percolating down through the tunnel roof. That could look as primitive in 100 years as the Wright brothers’ 1903 Flyer looks to us in 2004. Or it might simply be obsolete. Space-launch technology could become as reliable as jet airplanes are today, giving us a nearly foolproof way to throw waste into solar orbit. The mysteries of geochemistry might be as transparent as the human genetic code is becoming, which would mean we could say with confidence what kind of package would keep the waste encased for the next few hundred thousand years.

Or there might be easier ways to process the waste. For example, particle accelerators, routinely used to make medical isotopes, could provide a means to make the waste more benign. The principle has already been demonstrated experimentally: firing subatomic particles at high-level radioactive waste can change long-lived radioactive materials to short-lived ones. Richard A. Meserve, a former chairman of the U.S. Nuclear Regulatory Commission and now the chairman of a National Academy of Sciences panel on nuclear waste, says this technology, known as transmutation, might become more practical in 100 years. The technology of accelerators has advanced in the last few years, he says, and it is a good bet that it will continue to do so.

Some alternative storage technologies may need only a few more years of research and development. One is ceramic packaging. Ceramics have good resistance to radiation and heat, and they don’t rust. At the moment, nobody casts ceramics big enough to hold fuel assemblies, which are typically about four meters long. But there is no theoretical limit to the sizes of ceramics; there has simply been no economic incentive to make giant ones. Nor will there be, until the only likely customer for them, the Energy Department, decides that the metal it is shopping for now isn’t up to the job.

Another alternative calls for mixing waste with ceramics or minerals to form a rocklike material comprising about 20 percent waste. The waste would be chemically bound up in stable materials that are not prone to react with water. With a few decades’ grace time, engineers could build samples and test them in harsh environments. But even though the idea has been around for more than 10 years, no one has put serious research money into it, since its only possible American customer, the Energy Department, has been committed to Yucca.

That situation shows no sign of change. The Energy Department, following Congress’s orders, has so far declined to consider alternatives. Man-Sung Yim, a nuclear researcher at North Carolina State University in Raleigh, argues that some of these technologies are already mature but have been shoved aside in the Energy Department’s rush, possibly futile, to open Yucca. “My reading at this point is, people working at the Yucca Mountain project office do not really want to change the design. The more change you bring in, the more delayed the processes,” Yim says. “It’s a pity, because we could make it better.”

Central Casking

But the pursuit of the perfect solution (assuming deep geologic disposal even could be perfected) has ignored a realistic solution. And when the perfect fails, as now seems likely, we will be left with something no rational person would have chosen: waste sites scattered from coast to coast, in places where reactors used to be, each with its own security force, maintenance crew, and exclusion zone. “We’re here to run a business as efficiently as possible,” says John Sanchez, the project manager who oversaw the planning for the pad at Indian Point when he worked at Consolidated Edison, the site’s former owner. “In a perfect world, you would not have 60 of anything, if you could have one.” But after 20 years of pursuing geologic disposal, and 15 years of chasing Yucca and avoiding any mention of a plan B, just such an ad hoc, and suboptimal, solution is emerging.

And it’s emerging without the support of the Energy Department. Testifying before the Senate Energy Committee over the summer, Kyle McSlarrow, the Energy Department’s deputy secretary, said that “continued progress toward establishing a high-level waste repository at the Yucca Mountain site is absolutely essential.” He told another committee on the same day that with progress toward Yucca’s opening, “industry saw clearly that the nuclear-power option was truly back on the table.” (The department would not make McSlarrow or other officials available for comment for this article.)

Cask storage is not pretty, but what’s wrong with the idea of an industrial repository, a few hectares set aside for the next century or so, a single, guarded location in a little-populated area, a location that in ten years or so will be remarkable only because it’s a place where the snow doesn’t stick? Macfarlane of MIT says making such site secure and terrorist-proof would cost $6.5 billion, at most. “Isn’t that worth it? How much have we spent on Iraq? Look what we got for that money. And there’s more at risk here,” she says.

Finding a central site poses obvious challenges; nobody wants any type of radioactive waste site in his or her backyard. But after extended negotiations, a group of utility engineers, including Sanchez, cut a deal with the Skull Valley band of the Goshute Indian tribe for a long lease on part of its reservation 80 kilometers west of Salt Lake City. The area already hosts an air-force bombing range, a nerve gas depot and incinerator, and a dump for low-level radioactive waste; the Goshutes figure they can use the rent to buy themselves land in a nicer neighborhood.

Some experts think the federal government could take over the Goshute project and push it to completion, but there is a snag – an ironic one, given the fears of a September 11-style attack on a nuclear site. The Nuclear Regulatory Commission has determined that an F-16’s crashing into the casks on its way to or from the test site is a “credible accident.” But while such a crash would doubtless be disastrous, casks do provide some safety advantages over today’s fuel pools. The fuel in casks is much more spread out and does not require a flow of cooling water to prevent spontaneous, spreading fire. Thus the worst-case effects are more limited. In any case, one remote central site would be easier to protect with air defenses than numerous scattered sites.

Those scattered sites are already creating local problems. The casks from the former reactor in Wiscasset, ME, are blocking the redevelopment of the peninsula where they’re stored, a valuable industrial site. A cask site near the Prairie Island Nuclear Generating Plant in Welch, MN, is adjacent to a tribal day-care center and casino, which is nobody’s idea of a long-term solution. Inevitably, in the wake of September 11, the Indian Point casks will be a locus of fear. These outcomes will seem even sillier in 30 years, when many of the reactors that made the waste are gone.

Sanchez recalls carrying a picnic lunch to the stand of maples and black-walnut trees now being replaced with a concrete pad for storing nuclear waste. As the years roll by, fewer and fewer people will know those trees existed. Several decades from now, as today’s aging nuclear power plants are decommissioned, people may not remember that the reactors themselves existed. If we don’t take action soon, however, casks of waste will stand alone on that bluff above the Hudson River – and in dozens of other places across the country.

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