Tomorrowland (14 page)

Obviously, a carbon tax or more government handouts could change this picture, though the National Resource Defense Council computed that we would have to tax carbon at $40–$60 per ton for nuclear power to be competitive. That said, these numbers are based on a ten-year timetable for nuclear plants construction at a cost of $6–10 billion per gigawatt. General Electric just completed two nuclear plants in Japan; the first was done in thirty-six months, the second in thirty-nine. Both came in with a final cost of $1.4 billion per GW.

Still, cost is not the only factor. Environmental unpredictability is a bigger concern. How long until the oil runs out? How long until our supplies of natural gas are gone? Do we have five years
to stabilize the climate or do we have fifty? Because, if we only have five, forget the economics, there’s simply no way to build enough new nuclear power plants in time. But even if we have fifty, when it comes to nukes, is the risk worth the reward?

In trying to answer this question, Princeton’s Robert Socolow and Stephen Pacala, codirectors of the Carbon Mitigation Initiative, have created the concept of “stabilization wedges.” These are the 25-billion-ton “wedges” that must be cut from predicted emissions in the next fifty years to avoid doubling atmospheric carbon dioxide to pre–Industrial Revolution levels.

They explore fifteen different approaches, from wind power to transportation efficiency to reducing deforestation. Nuclear power is also on the list. They point out that fission currently produces, with zero carbon emissions, 17 percent of the world’s electricity, and that doubling this number could cut emissions by one wedge (out of seven total) if the resulting power is used to displace coal. But, because of concerns over waste and proliferation, they argue that nukes are the only technology out of their fifteen that we might want to skip. However, another question remains: Which nuclear technologies do we want to skip?

4.

When scientists talk about nuclear reactors, they denote them by generation. Generation I reactors were the ones built in the 1950s and 60s. Generation II began in the 1970s, and comprise all the reactors currently supplying power in the US — predominantly light-water thermal reactors that burn a combination of 3 percent
fissile
Uranium-235 (U-235) and 97 percent
fertile
U-238.

The difference is stability. All reactors work by bombarding heavy metals with neutrons. When a neutron hits U-235, the nuclei split — thus fissile — releasing both energy and a few more neutrons. U-238 is fertile because sometimes it splits, but occasionally
it absorbs that neutron and transmutates into plutonium (P-239), which, when it later fissions, produces even more energy.

These days, the fuel cycle for reactors lasts three years. By the end of it, less than 1 percent U-235 remains, and more than half the power generated comes from splitting plutonium. The results are a three-part waste product. About 5 percent of which is composed of lighter elements that remain radioactive for around 300 years (this has been called the “true ash from the nuclear fire”). Another 94 percent is uranium, not all that different from the version we mine from the ground. But the remaining 1 percent is a blend of plutonium elements, augmented by americium, and this is the stuff that stays “hot” for tens of thousands of years and requires secure storage sites like Yucca Mountain to protect.

For this reason, in 1976, the UK Royal Commission on Environmental Pollution declared it “morally wrong” to make a major commitment to nuclear power without demonstrating a way to safely isolate radioactive waste. Attitudes haven’t changed much. But waste is not all that it’s been made out to be. “All the spent fuel from power plants and other sources since the beginning of nuclear power in the US fifty years ago is so small in volume that it could fit in a Walmart stacked to a depth of nine feet,” says Cravens. “All the spent fuel generated in the annual operation of a single reactor would fit in the bed of a standard pickup truck.”

To deal with this detritus, many suggest that the right way to go is to follow France’s lead and recycle our spent fuel. America (and Sweden, Finland, Canada, Spain, and South Africa) utilize an “open, once-through fuel cycle,” in which nuclear fuel is processed only once. But the French take that resulting plutonium, purify and oxidize it, then mix the results with fresh uranium to make MOX — essentially fresh fuel — and restart the whole cycle. This is known as the Plutonium Uranium Extraction (PUREX) process. America was firmly committed to this path as well, but in 1976 India developed nuclear weapons from a version of reprocessing
technology and a lot of people got very scared, including then President Jimmy Carter.

By executive order, Carter cancelled development of any domestic reprocessing in 1977. His goal was to set a nonproliferation example for the world, which the world pretty much ignored. So Reagan lifted the ban in 1981, but didn’t provide money to restart research. Nothing resumed until 1999 when the Department of Energy finally reversed their policy and signed on with a business consortium to build a reprocessing plant in South Carolina. Who knows when it’ll be open. Until then, there are 55,000 tons of nuclear waste in storage in the US.

Since the PUREX process — by separating the plutonium — raises proliferation concerns, perhaps this form of reprocessing isn’t the best solution. But the other problem is inefficiency. When uranium finishes a once-through process, only 5 percent of its potential energy is used. When reprocessing plutonium, that ticks up to 6 percent. This still leaves 94 percent of that fuel’s potential energy and, since uranium is neither an infinite resource nor environmentally friendly to mine, we would do well to tap these remains.

And this is where newer technology comes into play.

5.

Generation III reactors are one example of a newer technology. These are streamlined light-water reactors with significantly better safety systems. They are also built modularly, allowing them to be manufactured in factories and keeping costs significantly down. There are currently two Generation III reactors deployed in the world and two more under construction. But it’s really the generation after Generation III that has people so excited.

Conventional nuclear reactors are called “thermal” reactors, because the speed of the neutrons flying around within them has been slowed down to produce thermal energy. This happens
by using a “moderator” — usually water (thus the light-water reactors). Fast reactors, which are what we’re talking about with Generation IV, don’t have moderators, thus the neutrons bounce around at a much faster rate, allowing more energy to be extracted from fuel.

Also, because water slows down neutrons, fast reactors use liquid metal — mostly sodium — as a coolant. The advantage here is that water-cooled systems need to run at very high pressure, so a small leak can quickly become a large problem. Liquid-metal systems run at atmospheric pressure and don’t have that trouble; instead, they have other concerns.

Liquid sodium is not the most stable of substances. Expose it to water or air and the result is fire. The reason most people haven’t heard about this technology is because early iterations did catch fire. The EBR-I that melted down in Idaho was an experimental fast reactor, as was Japan’s prototype Monju reactor, which burst into flames in 1995 and has remained shut down ever since. Other iterations suffered a similar fate. In 2008, Thomas Cochrane, a nuclear scientist with the National Resources Defense Council, testified before the House of Representatives on this technology:

Despite decades of research costing many tens of billions of dollars, the effort to develop fast breeder reactors has been a failure in the United States, France, United Kingdom, Germany, Italy, Japan, and the Soviet Union . . . After investing tens of billions and decades of effort in fast breeder R&D, Congress should ask itself why there is only one commercial-size fast reactor operating in the world today — one out of approximately 440 reactors. NRDC knows why. Fast reactors are uneconomical and unreliable.

Yet there’s still more to the story. The original nuclear dream was to take spent fuel from thermal reactors and use it to power fast reactors. These were then called “breeders,” as they bred more plutonium than they consumed. “In the early days,” says Cravens, “before we discovered the uranium on the Colorado
Plateau, there was a real concern that we would run out. Breeders were the solution to that problem.”

Work began on that solution with the EBR-I in 1951 and progressed into the EBR-II in 1964. “Sure, EBR-I partially melted down,” says Dave Rossin, former president of the American Nuclear Society and Assistant Secretary of Energy under Reagan, “but this was in the day when being intelligent was still allowed. People studied what went wrong and made changes and the result was EBR-II, which started up in 1964 and ran perfectly until the 1980s. Unfortunately, by then, anything called a ‘breeder’ was frowned upon in Washington and the project was shut down for political reasons.”

In 1984, trying to avoid that fate, scientists at Argonne National Laboratory renamed their breeder reactor the Integral Fast Reactor (IFR). By 1992, the IFR designs were complete, but then Bill Clinton decided to save money by shutting down any nuclear projects he deemed unnecessary. “It’s a crime,” says former Argonne nuclear physicist George Stanford. “We set out to build a reactor that addresses all the nuclear concerns: safety, efficiency, proliferation, and waste. It worked perfectly. IFR solves all our problems. And it’s just sitting on a shelf.”

Among the problems “solved” by IFR is safety. Liquid metal fuel expands when heated. As the metal expands, its density decreases. This changes the geometric trajectory of the neutrons bouncing around inside and the laws of physics don’t allow it to sustain a chain reaction. “It can’t melt down,” says Stanford. “We know this for certain because in public demonstrations using the EBR-II, Argonne duplicated the exact conditions that led to both the Three Mile Island and Chernobyl disasters and nothing happened.” This is known as “passive safety” and every Generation IV reactor works this way.

Proliferation is another problem solved. An IFR reactor is built so that whatever fuel enters always leaves as electricity. What’s actually inside the reactor — if terrorists, say, seize a
facility — is far too hot to handle, so the main result of such an attempt would be dead terrorists. And the waste is only a fraction of what’s produced by thermal reactors (a 1000-MW thermal reactor produces slightly more than 25 tons of spent fuel annually; a fast reactor generating the same power produces one ton). Moreover, this waste doesn’t contain weapons-usable material, only stays “hot” for several hundred years, and remains as an inert solid — essentially stored as glass bricks — so even if the containment facility were to breach, it can’t leach into the ground water.

All of this explains why, in 2002, the US Department of Energy organized the most comprehensive study of nuclear design options ever conducted, asking over 250 scientists to rank nineteen existing nuclear options based on twenty-seven criteria. IFR came in at number one. For this reason, Columbia University professor and head of NASA’s Goddard Institute, James Hansen — often credited with being the first person to sound the alarm bells about global warming — put IFR on his top-five list of things we need to do to stave off climate disaster. Both China and India jumpstarted IFR programs (China’s first fast reactor started producing electricity in 2011). “The truth of the matter,” says Tom Blees, “is once most anti-nuke people hear about IFR, they tend to switch sides pretty quickly.”

6.

Beyond IFR, there are two remaining new nuclear technologies that have people’s attention: Liquid Fluoride Thorium Reactors (LFTR, pronounced
lifter
) and Small Scale Nuclear Reactors (SMRs). We’ll take them one at a time.

LFTR began its life as a solution to a peculiar 1940s Air Force question: Can we use nuclear power to fly a bomber indefinitely? The basic answer was yes, but intercontinental ballistic missiles
turned out to be a better way to fight the Cold War. Before that happened, research on the project was spread among a number of different centers, though Oak Ridge National Laboratory took the lead throughout the 1960s, even building a prototype LFTR reactor that went critical in 1954 and ran for 100 hours nonstop before being shut down.

After that program was cancelled, the idea never quite went away. A small cadre of Oak Ridge scientists kept it alive. Lately, the cadre has been expanding, primarily because LFTR has some significant benefits over other nuclear technologies — mainly the fact that it runs on thorium.

Thorium is a mildly radioactive element found in significantly greater quantities than uranium. As there are growing concerns about our dwindling uranium supply — some experts predict we could run out of our main nuclear fuel within 100 years — this is good news. More important, thorium provides more bang for our buck. In a standard thermal reactor, it takes 250 tons of uranium to create a gigawatt-year of electricity. LFTR requires only one ton of thorium to produce the same output. And less fuel makes for less waste. A lot less. Thorium creates less than 1 percent of the waste of a standard light-water reactor, and most of that “waste” isn’t waste — rather a collection of valuable elements like rhodium.

Finally, LFTR allows for continuous refueling, meaning the reactor never stops operating, which makes it both incredibly efficient and a lousy target for terrorists intent on theft of nuclear materials. This level of safety and efficiency could lead to assembly-line production, making thorium reactors the Model T of nuclear designs. “To stop global warming,” says Kirk Sorenson, chief technologist for the Energy from Thorium Foundation, “we need thousands of new reactors worldwide; currently we have hundreds. It took three years from when they invented the fluoride reactor until they built the first one. That was fifty years ago, and we know a lot more about how to do it now.”

It’s for this reason that a number of countries now have serious thorium programs underway. India, which has abundant thorium reserves, plans to generate 25 percent of their electricity from the element. China, meanwhile, is being even more aggressive. Asia’s giant has a dedicated team of 750 researchers working the problem and plans to have its first thorium reactor up and running by late 2015. In the US, TerraPower, founded by former Microsoft chief technology officer Nathan Myhrvold, with backing from Bill Gates, is working on a “traveling wave reactor” — often described as “the world’s most passive fast breeder reactor” — that will be able to run on both thorium and uranium and is due, in prototype form, by 2020.