Clean, efficient, cheap - in many respects, nuclear energy looks like a nearly perfect way to generate electricity. Yet perhaps no other mode of power is as feared. One major reason is the question of how to dispose of nuclear waste - a concern reawakened by the crippling of the nuclear plant at Fukushima, Japan. More than 56 years have passed since the first nuclear plant for civilian power generation went online, but there is still no consensus on the best way to dispose of dangerous waste. (Second in a series on the future of nuclear power)

On April 11, one month after a massive tsunami set in motion equipment failures that severely damaged three reactors in a Fukushima, Japan, nuclear power plant, the owner of the plant, TEPCO (Tokyo Electric Power Company), announced that it had been forced to dump 11,500 metric tons (more than 2.6 million gallons) of somewhat radioactive water into the sea to make room in its storage tanks for water that is much more radioactive.

The incident highlighted an ongoing problem for the nuclear industry. Since the Fifties, industry cheerleaders have touted nuclear energy as a clean and safe alternative to conventional power generation. They talked about backup systems. They reassured people that there were physical reasons a nuclear reactor could never, ever explode like a bomb. But there was one area even the most vocal boosters tended to be a bit quiet about: how to dispose of the waste after the uranium fuel rods are spent.

The problem of waste disposal has stayed on nuclear developers’ to-do list for five decades. The technical difficulty of disposing of such “hot” material for as much as a million years, coupled with the political need for a perfect rather than a good solution, has stymied progress all over the world. In Japan, as in most of the rest of the world, nuclear waste is stored above ground, awaiting a more permanent solution.

But in many countries, pressure may be building now to resolve the question. The global need for more energy, particularly energy that doesn’t create more greenhouse gases, and the reminder of the Fukushima disaster about the potential dangers of a nuclear mishap, seem to be pointing a way toward a political reaction that will either speed adoption of nuclear power or consign it eventually to a decreasing role in energy production – an impressive technology that like the Concorde didn’t ultimately fit the needs of the market.

Weighing the Options
Scientists have considered many options for nuclear-waste disposal, everything from burial underground to blasting into space, but no consensus has ever emerged.

In Europe, one solution has been to simply export the waste, principally to Russia – a practice banned in November 2010 by the European Union. In the past, French, German, and Hungarian nuclear companies have all exported some of their spent nuclear material to Russia. In all, more than 700,000 tons of European nuclear waste is now held at various locations in Siberia, according to estimates of Bellona, a Norwegian environmental foundation. Much of the waste is ostensibly tailings meant for reprocessing, but foundation analysts are skeptical that the depleted uranium will ever be reprocessed.

Aside from export, three basic approaches to nuclear-waste disposal are now being used or advocated.

The first mode is reprocessing. The initial pass of the uranium core in a nuclear plant uses only 4 percent of the nuclear material, according to a paper by Bill Magwood, a former senior nuclear power official in the United States, and Mark Ribbing, the director of policy development at the Progressive Policy Institute – a practice they liken to taking a log out of the fire after the bark has been burnt off. The thrifty French reprocess that fuel, which eventually reduces the remnants to a tiny percentage of what was left after the first pass, around 10 grams (or three-tenths of one ounce) annually for every person in France – a fraction of the waste that the American program must cope with.

The downside? Reprocessing is the same technology used to make the kind of nuclear material that goes into nuclear weapons – and a key reason the Carter Administration stopped supporting research in that area back in the Seventies, according to Magwood and Ribbing. Concerned about the potential for nuclear weapons proliferation, the Carter team shut down plans to develop processing plants in the United States.

The second approach, still on the drawing board, is burial. France is currently planning a waste-disposal facility in Bure, in the northeastern part of the country. Another is being planned in Sweden, where SKB, the Swedish Nuclear Fuel and Waste Management Company, has applied for government approval to build a permanent repository in Forsmark.

SKB technicians will encapsulate the spent fuel in copper canisters, embed the canisters in clay, and then bury them at a depth of about 500 meters. The canisters will be nearly five meters long, more than a meter in diameter, and five centimeters thick, according to SKB’s Web site.

The clay should help protect the canisters from movements in the rock and act as a barrier to keep water from getting into a canister, should it break. It should also help keep the canisters from leaking into groundwater. After disposal, the tunnels and rock caverns will be sealed with the same clay.

The idea has not met with large protests in Sweden. “It is more or less accepted,” says Frigyes Reisch, a professor of nuclear power safety at the Royal Institute of Technology (KTH) in Stockholm.

The downside? “It is very, very expensive,” Reisch says. “Many people think that Sweden is overdoing it with this repository.”

Often, the concept of burying the waste is combined with vitrification, the processing of waste into a ceramic or glass form. This process doesn’t make the material less toxic, but it does make it less likely to leak, at least for several thousand years. Over the last 15 years, a U.S. government plant in Aiken, N.C., has converted Cold War-era military waste to glass on a large scale: putting more than 43 million liters (11.7 million gallons) into 3,000 canisters roughly 3 meters tall (10 feet) and 75 centimeters wide (two feet). Laid end to end, the containers would be as high as 24 Empire State Buildings, around 9 kilometers (5.5 miles).

Unfortunately, a 2005 pilot project at another government facility at Hanford, Washington, suggested that vitrification may not be as stable as imagined.

The third approach is above-ground storage. The French have been using a single well-guarded facility to handle the material that wasn’t exported. The Americans, on the other hand, store waste onsite at each of the country’s 104 nuclear plants. Plans dating from 1978 to bury the waste under the remote Yucca Mountain in Nevada have not gone forward, partly out of concern about the risks of carting waste from all over the United States.

Above-ground storage has been a kind of de facto compromise between opponents of nuclear power who want to make sure the permanent solution has no chance of failure and proponents who don’t want the plants shut down until such a solution is reached.

Above-ground storage may be less worrisome than it sounds. Some authorities argue that perhaps the safer thing is to leave the waste above ground and under observation for a century or more, at which point much more will presumably be known about the decay of nuclear material.

But the perception that above-ground storage is an interim solution is part of what has kept the U.S. nuclear program from expanding for the past 30 years, since the Three Mile Island accident in 1979. Several states, in fact, have rules that specifically prohibit the licensing of new plants until the adoption of a national storage plan. And concerns about the above-ground approach- in the United States and elsewhere – have only been exacerbated by the dangers posed by spent fuel stored at Fukushima.

The Perfect as the Enemy of the Good?
Other experts believe that the issue with nuclear-waste disposal is not so much technical as educational – teaching society to accept a certain degree of risk as inevitable.

Vaclav Smil, a professor of the environment at the University of Manitoba, in Canada, is confident that safe burial is possible. “We [can use] large areas of the earth’s crust – rocks … that have been sitting there for billions of years, lots of geologically stable formations,” argues Smil. “It is not a technical problem.”

The real issue, Smil says, is acceptance of the risks. “People are willing to smoke and overeat and drive their cars fast, but involuntary risks they will not accept, although it’s very small. Even educated people cannot perceive risks correctly.”

Perhaps, contends William Nuttall, a senior lecturer in technology at the Judge Business School at Cambridge University, the nuclear industry has been trying to solve the wrong problem all along.

“For 50 years,” Nuttall says, “the industry has heard that the public is frightened of the dangers of nuclear power and for 50 years they have worked to reduce the danger, when they should have arguably worked more to reduce the fear.”

What may continue to feed the fear, though, is the never-ending specter of the ruined nuclear plant at Chernobyl. As the 25th anniversary of that disaster was marked on April 26, plans were still being discussed about constructing a “permanent” tomb to encase the plant and its vast amounts of radioactive material, now shielded by a crumbling sarcophagus. The sparsely populated “Zone of Alienation” that surrounds Chernobyl, covering 4,300 square kilometers (1,660 square miles), remains pockmarked with contaminated soil and radioactive seepage.

Whether a similar fate awaits the six reactor buildings at Fukushima, the worst nuclear mishap since Chernobyl, is not clear. At the moment, it seems unlikely. But one of Chernobyl’s lessons is that the biggest piece of nuclear waste of all can be the plant itself.

In the next article in this series, we compare the risks of nuclear power against other forms of electricity generation. How do the risks really stack up?

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