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Whither nuclear? (U.S. DOE)
Can Nuclear Win a Spot at the Climate Defense Table?
June 2007
After decades in the doghouse, nuclear energy is getting a second look, if not yet a second wind, largely because of rising concerns about global warming.
Nuclear, which supplies about one-sixth of the world’s electricity and 20 percent of America’s, is back in play because of the daunting energy equation that human civilization must solve. Between now and 2050, worldwide energy consumption is expected to double. At the same time, greenhouse gas emissions must be cut in half in order to prevent dangerous climate change.
That will be hard. Take nuclear energy out of the picture and solving that equation will become harder. Keeping nuclear in the picture creates another set of difficulties, however: handling nuclear’s baggage of cost, safety, radioactive waste, and weapons proliferation issues.
Whether the baggage train is a manageable challenge or an insurmountable barrier to nuclear energy expansion has not been settled. The Keystone Center, an independent public policy institute, recently gathered a group of utility, environmental, academic, and government experts to develop a set of baseline conclusions to inform debates about such questions. The resulting report was published June 14.
First question. How much could nuclear power plants contribute towards carbon dioxide emissions reductions? Or, to put the question into the "wedges" framework that makes the climate question seem more manageable, what would it take for nuclear to contribute one wedge of emissions reductions?
One wedge equals 25 billion tons of reductions over 50 years. To stabilize global greenhouse gas emissions during that period, the world must meet an emissions reduction budget of seven wedges.
To achieve one wedge, total nuclear generation capacity worldwide would have to be three times today’s level. Providing that extra capacity, in addition to replacing retired plants, would require construction of about 21 garden-variety, 1,000-megawatt nuclear plants each year for 50 years.
The nuclear industry would have to "return immediately to the most rapid period of growth experienced in the past (1981-1990) and sustain this rate of growth for 50 years," the Keystone report says. A concomitant increase in uranium mills, fuel fabrication plants, and waste repositories would be necessary as well.
As of the end of 2006, only 216 nukes were under construction, planned, or proposed -- far fewer than the number needed to achieve one wedge of greenhouse gas emissions reductions.
Putting a price on carbon would boost nuclear’s prospects to a degree. The Intergovernmental Panel on Climate Change has estimated that putting a $50-per-ton charge on carbon dioxide would stimulate modest growth in nuclear’s share of worldwide electricity generation from 16 to 18 percent.
Without a carbon charge, nuclear costs more on a life-cycle basis than coal or natural gas. But nuclear’s economic prospects are shaped by more: perceptions of capital risks and opportunities, public acceptance, electricity market structures, supply chain bottlenecks, and government support.
In the U.S., nuclear "merchant" plants that lack a revenue base of retail customers will have a harder time gaining a foothold than nukes built by utilities to serve retail loads under conventional cost-of-service rate regulation.
Not that utilities building for the retail market will have a walk in the park. State utility commissions, once burned and twice shy by nuclear construction cost overruns in the 1970s and ‘80s, may impose conditions on utilities planning new nukes in order to protect consumers. One such condition could be cost caps.
Utilities eyeing new nuclear plants also will face questions about public acceptance tied to plant safety perceptions. The Keystone report says that, overall, U.S. nukes are safer now than they were at the time of the Three Mile Island accident. Better equipment and training have resulted in safety improvements.
Still, safety oversight is not perfect. In 2002, workers at the Davis-Besse plant near Toledo, Ohio, found a dangerous cavity in the reactor pressure vessel that had gone undetected for years.
Regardless of how safely nuclear power plants operate, all of them produce highly radioactive waste that must be isolated from the environment for millennia. Each one of those garden-variety, 1,000-megawatt nukes produces 20 metric tons of waste per year.
Participants in the Keystone study agreed that deep geologic storage is the best way to keep radioactive waste away from the biosphere. Easier said than done in the U.S., however. Under a 1987 federal law, the Yucca Mountain site in southern Nevada is the only candidate to hold waste from the 103 commercial reactors operating in the U.S. The Yucca Mountain project is years behind schedule, technical issues remain unresolved, and the first shipments of waste canisters might not begin until 2021 -- nearly a quarter-century after the original deadline.
The licensing process has an element of the surreal. EPA, following the dictates of an appeals court decision, has proposed a standard to protect the biosphere from radiation exposure after the waste canisters eventually fail. The proposed standard extends out to 1 million years in the future. Can the federal government extend its writ 40,000 generations into deep time? Skeptics may be excused for having their doubts.
In addition, Yucca Mountain’s storage capacity is limited by law. To facilitate expansion of nuclear energy, additional repositories would have to be identified, characterized, and licensed. One way to buy some time would be developing interim storage sites for holding wastes in sturdy dry casks.
How about reducing waste by reprocessing it to extract usable fuel? So far, the Keystone report said, the economics of reprocessing aren’t competitive with today’s "once-through" fuel cycle. In addition, there would still be residual waste requiring geologic storage. And there appears to be plenty of uranium to support once-through cycles for several decades. At least for the near future, the conventional light-water reactor will likely be the nuclear technology of choice.
Reprocessing involves separating fissionable plutonium and uranium from the fiery brew of radioactive wastes that plants produce. And that sets nerves twitching with thoughts of terror organizations, rogue regimes, or both getting their hands on materials that could be fashioned into nuclear weapons.
Keeping civilian nuclear materials out of the wrong hands is the job of the International Atomic Energy Agency (IAEA). The Keystone report doubts whether the treaty safeguards that IAEA enforces are carried out rigorously enough to ensure foolproof detection of bad actors diverting fissionable materials to clandestine bomb factories.
To remedy the interconnected waste and proliferation problems, the Bush administration has proposed a Global Nuclear Energy Partnership (GNEP). The idea is to develop a controlled network of facilities that would provide fuel fabrication and waste reprocessing services to the civilian nuclear sector worldwide.
But the Keystone report raises considerable doubts aout whether the GNEP concept is workable. No one is sure whether the proposed reprocessing technology would be either feasible or economical. Nor is there any assurance that "fast" reactors designed to use up plutonium and other fissionable waste by-products would either be practical or cost-competitive. Members of Congress on both sides of the aisle are skeptical about funding GNEP.
With all of the barriers that await expanded nuclear development, one who reads the Keystone report might be tempted to let nuclear energy fade away once existing plants are retired. But that would be a gamble with its own set of risks. Coal would be the most likely replacement. No one knows for sure whether carbon dioxide capture and sequestration will be cost-effective and practical on the immense scale necessary to safeguard the climate from unfettered coal burning.
It’s too early to pick technological winners. Keeping the atmosphere’s carbon load from getting out of hand means keeping nuclear in the game. For that to happen, however, there must be a price on greenhouse gas emissions, resolution of waste storage issues, and stronger safeguards against diversion of fissionable materials.
With all its baggage, nuclear still holds promise as part of a larger technological package that keeps humanity from crossing into the red zone of climate instability.
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