[This is Part 2 of an In-Depth Report on The Future of Nuclear Power.]

Brown's Ferry is the name of an unprepossessing boat crossing on the Tennessee River in Alabama. It is also the birthplace of a revival for nuclear power in the U.S. In May 2007 the one gigawatt-electric nuclear reactor known prosaically as Unit 1 restarted boiling water—after a 22-year shutdown and a refurbishment that cost $1.8 billion.

Brown's Ferry is just the first. The Tennessee Valley Authority (TVA), owner of the three nuclear reactors at Brown's Ferry, also has plans to complete a stalled reactor at Watts Bar in Tennessee and two new reactors at Bellefonte in Alabama; Princeton, N.J.–based NRG Energy wants to build two new reactors at its South Texas nuclear power facility.

And North Carolina–based Progress Energy hopes to replace two old coal-fired power plants with two new nukes near Florida's Tampa Bay by 2017 at a cost of roughly $7 billion apiece—a price tag already incorporated into the company's bills to local ratepayers. If built, the two units would be the first brand-new nuclear power plant ordered and constructed since the Palo Verde plant in Wintersberg, Ariz., in 1973—a full 25-year moratorium on new construction could be drawing to a close.

"There continues to be a demand for power and a certain percentage of that power needs to be baseload" (an industry term for electricity that is always available), says Adrian Heymer, senior director for new plant deployment at the Nuclear Energy Institute (NEI), a Washington, D.C.–based industry group. "What is it going to be? Coal is not favorable at the moment and natural gas is volatile [in price]. So people are looking at nuclear."

The federal government echoes those sentiments. The Bush administration pushed though loan guarantees, whereby the costs of delays in construction would be paid for by U.S. taxpayers, and the Obama administration has indicated its support for new nuclear power plants. "Nuclear power, as I said before, is going to be an important part of our energy mix," said physicist Steven Chu, Obama's secretary of energy during his confirmation hearing on January 14. "It's 20 percent of our electricity generation today, but it is 70 percent of the carbon-free portion of electricity today. And it is baseload. So I think it is very important that we push ahead." He added: "There is certainly a changing mood in the country because nuclear is carbon-free, that we should look at it with new eyes."

The United Nations Intergovernmental Panel on Climate Change (IPCC) agrees, noting that nuclear could make "an increasing contribution to carbon-free electricity and heat in the future" provided that fuel constraints, costs, waste management, safety and "adverse public opinion" could be overcome.

Already, utilities have filed 17 applications for 26 new reactors and the U.S. Nuclear Regulatory Commission (NRC), the federal agency charged with overseeing the nuclear power industry, expects three more applications for five more reactors this year.

But like fingerprints, no two nuclear reactors in the U.S. are exactly the same for the most part—even those that sit right next to each other in the same facility. In large part, this is because all nuclear reactors were designed while they were being built, leading to a host of changes—and a host of delays. "We have 104 custom-built plants" in the U.S.," says Craig Nesbit, vice president of communications for Illinois-based utility Exelon, the owner and operator of 17 reactors, the largest fleet in this country.

The first new nuclear reactors in the U.S. in 30 years will be no exception: NRG hopes to build two new boiling-water reactors on the same South Texas site where it currently operates two pressurized water reactors. "We wanted a technology built by someone on time and on budget," explained NRG CEO David Crane in an interview with Scientific American in 2007. "There was only one of the four [new reactor technologies] that satisfied that criteria, and that was the advanced boiling-water reactor."

But the second reactor at the Watts Bar site in Tennessee—mothballed in 1985 because of spiraling costs—will be the same as the one already operating, no matter how long that takes or whether its technology is the best. "We looked at all the different methods that you could generate electricity with and found that [nuclear] was the cleanest, safest, most reliable and also the lowest-cost method of providing that additional baseload generation," said Ashok Bhatnagar, TVA's senior vice president of nuclear operations who is in charge of building the new reactors, during a tour of Watts Bar in 2007. Of course "we haven't really had major construction in this country for a very long time."

Central planning
The twin cooling towers, built to accommodate two reactors at the Watts Bar nuclear power plant, stand at a bend in the Tennessee River, but only one billows steam into the air. Starting operation in 1996—after 23 years of construction plagued by delays and costly mistakes—the pressurized water reactor there takes its name from a sand bar that once plagued riverboats. Construction of the Watts Bar Dam solved that problem and the reactor relies on this reservoir of river water to cool its reactor core and produce the steam that actually drives electricity generation.

Such pressurized water reactors employ the heat given off by fissioning uranium isotopes in fuel rods to heat a solution of water and boron, which helps to control the reactivity of the radioactive fuel by absorbing neutrons. The reactors get their name, though, from the fact that the water is under pressure, about 2,000 pounds per square inch (141 kilograms per square centimeter), to ensure that though it reaches about 600 degrees Fahrenheit (300 degrees Celsius), the water never comes to a boil.

This superheated, pressurized water then passes through a heat exchanger—known as a steam generator—and transfers that heat to regular water at lower pressure, turning it to steam. And this steam ultimately turns the turbines that produce the electricity. "It's just another power plant," says Greg Callaway, an NRC trainer and former operator at nuclear power plants throughout the country. "You would be able to tell this was a nuclear plant because of the lower pressure steam, but in principle it's the same as a coal plant."

But the Watts Bar reactor differs from some of its pressurized peers because it relies on ice to protect the core from a runaway reaction. A vast vault filled with ice stands ready to condense steam created during the cooling of an overheated reactor core, a safety design that has proved difficult and expensive to maintain. "They're a total bag of worms, and everybody who built one wished they didn't," Callaway says. "It requires so much money to maintain it…. Whatever money they saved in concrete [that would have been needed for larger containment buildings] they spent 10 times over."

Nevertheless, the new reactor at Watts Bar, built on the 60 percent complete skeleton already standing, will match the old one in every detail. "Why not something new like one of the new advanced reactor designs? It really is a value of time [decision]," Bhatnagar said. "At the end of this project we need to end up with an operating reactor on Unit 2 that is designed, licensed and operationally similar to Unit 1. To do that, what we also have to do is not just finish the things that are left over to construct on Unit 2, we also have to make all the modifications that were made to Unit 1 since its start."

Of course, this also means that Unit 2 will have to avoid all the mistakes that led to Unit 1 costing more than $7 billion to construct over 23 years, including having to redo some welds and replace more than one million feet of electric cable because of faulty installation and paperwork. "In some respects it's harder to tear apart and reconstruct than it is to just build from scratch," says Loren Plisco, NRC's deputy regional administrator for construction in the southeastern region, especially because both the NRC and TVA will have to make sure that the problems addressed in Unit 1 are also addressed in Unit 2.

TVA estimates that the new unit will only cost $2.5 billion to complete, which is anticipated to happen in 2013, making Watts Bar Unit 2 potentially the second new reactor to begin producing power. "We're looking at it as, in some ways, a training ground for the new reactors," Plisco says.

New reactors
The TVA is hoping to build advance-design reactors, as well. The authority is submitting an application for two more at its Bellefonte power plant. And these will be built from a truly novel design: the so-called AP-1000 developed by Westinghouse Electric Co., which is the first new reactor to be certified by the NRC—although it is currently undergoing further review after some modifications.

The AP-1000 is one of four new, so-called Gen III+ reactors, because it is part of the third round of revisions to nuclear reactor designs; the first of which, the Shippingport Atomic Power Station near Pittsburgh could produce just 60 megawatts of electricity and was also made by Westinghouse. In contrast, the AP-1000 will be capable of producing 1,154 megawatts-electric, according to its maker, an output similar to that of its peers: General Electric's advanced boiling-water reactor and AREVA's evolutionary pressurized water reactor.

A reactor design earns the plus in its name for its passive safety features—safety technology that kicks in with or without human intervention. In the case of the AP-1000, that means cooling water sits above the reactor core and, in the event of a potential meltdown like the 1979 event at Three Mile Island, Pa., will, with the opening of a heat-sensitive valve, simply flow into the reactor, shutting down the reaction. "Never has so much money been spent to prove that water runs downhill," says Vaughn Gilbert, a Westinghouse spokesman.

And, although the vessel containing the nuclear reactor is encased in a further shell of four-foot- (1.2-meter-) thick concrete, that shell is surrounded by a building that is actually open to the atmosphere. Should the concrete containment vessel heat up, natural convection would pull in cooling air. "If you don't cool it, the fuel melts," says Ed Cummins, Westinghouse's vice president of regulatory affairs and standardization. "You have to transfer that heat somewhere—either a large body of water or, in our case, to the atmosphere."

The simplicity of the design delivers other benefits, according to Gilbert, particularly in price. "Because the plant is simpler, with fewer pumps, less wiring and less heavy materials to put into the plant, it reduces your construction cost," he says. "It also decreases your long-term operating costs." Westinghouse expects to deliver AP-1000 for somewhere around $3,500 to $4,500 per kilowatt, according to Cummins, or more than $6 billion in total, assuming construction takes three years.

But what will such reactors ultimately cost? The answer will remain unknown until one is actually built as delays, mistakes and other holdups sent construction costs of the last round of nuclear reactors through the roof. Estimates range from at least $2 billion to as much as $14 billion—and reactors completed since the 1980s averaged costs of $4,000 per kWh of electricity, according to the Congressional Research Service (pdf). That, of course, affects how expensive the electricity they produce will be. "Quite frankly, we don't know," NEI's Heymer admits.

The nuclear industry maintains that nuclear power plants must not cost more than $4,500 per kilowatt to build. The Keystone Center in Colorado, which brought together utility executives, environmentalists and other experts to examine the future role of nuclear power, estimated in 2007 that ultimately nuclear power will cost between 8 and 11 cents per kilowatt-hour (kWh).

The U.S. Department of Energy (DoE), for its part, puts the average cost of a new nuclear power plant at $7 billion—which is more than one quarter of the average stock market value of all public energy companies that currently own a nuclear power plant. "Twenty-five-billion-[dollar] average market capitalization companies cannot underwrite many nuclear plants," noted Dennis Spurgeon, assistant secretary for nuclear energy at the DoE in a speech this past July.

Hence the loan guarantees, which will allow utilities to obtain preferable rates on any loans because of the backing of the U.S. government, says Duke Energy's Bryan Dolan, vice president of nuclear development. "It lowers the cost of capital and therefore enables owners to deliver to ratepayers at a lower rate." Although, he adds, "they are not critical for us to move forward."

Nevertheless, utilities like Duke applied for $122 billion worth of them, according to the DoE. Under the current program, the department has only $18.5 billion to offer. In addition, the 2005 Energy Policy Act provides 1.8 cents per kWh of electric power derived from new nuclear reactors.

"It's the only way the plants can be financed, that is at the taxpayer's expense," says Amory Lovins, an energy expert at the Rocky Mountain Institute. "In 2006 distributed renewables alone got $56 billion of private risk capital. Nuclear got, as usual, zero. What part of this do people who take markets seriously not understand?"

"The only people in the world who buy nuclear power plants are central planners, whether they are in governments like China or Japan or TVA, which is an unaccountable public utility," Lovins adds. And, at this point, only one out of the 26 proposed new reactors are being built in areas with deregulated electricity markets; utilities prefer to build them in still regulated areas where they can be guaranteed to recover the cost of construction eventually from ratepayers—much as Progress Energy is doing in Florida right now.

"At this point, having had subsidies for 50 years, they ought to be able to stand on their own two feet," says David Doniger, policy director of the climate center at the Natural Resources Defense Council, an environmental group. But, he adds, "we don't have a rigid antinuke position." And a Congressional staffer who declined to be identified noted: "If nuclear can compete on an even playing field with all the other carbon-free energy out there like wind and solar, then that's what they should do. They keep on coming back with hat in hand asking for tens of billions in subsidies with no plants being built, mostly because Wall Street and private investors want nothing to do with it."

"The global financial climate is causing some U.S. utility customers, primarily ones that are relying on the capital markets to finance their projects, to reprioritize needs and consider options for the construction of new nuclear power plants," said Jack Fuller, president and CEO of GE Hitachi Nuclear Energy, in a statement. "We do believe the nuclear renaissance will happen, both in the United States and globally. We've been in the nuclear business for 50 years, and we are in this for the long haul."

The former head of the TVA—S. David Freeman—notes that much of the $25-billion debt that TVA still has today is a result of the catastrophic financial burden imposed by a plan to build 17 nuclear reactors in the late 1970s, of which only six were ever completed. "The idea that we should build a whole lot more radioactive factories in this age of terrorists doesn't make a whole lot of sense to me," he told the Chattanooga Times Free Press, noting that the power from such plants would likely cost as much as 12 cents per kWh, compared with roughly 8 cents per kWh from existing power plants in the TVA system.

Going nuclear
Cost is not the only reason for concern. New nuclear power often means building new transmission lines, a politically and financially delicate process. The heat exchangers known as steam generators have turned out not to last as long as originally thought, necessitating costly replacements. And, perhaps most importantly, almost no one is left from the labor force that built the last round of nuclear reactors.

"The last time we really built a plant from scratch was 30 years ago," NEI's Heymer notes, and the group has initiated regional training to ensure there will be enough workers, for example, with the certification and skills needed to weld at a new nuclear power plant.

But there's also the problem that the U.S. is not alone in restarting its nuclear industry; even the oil-rich United Arab Emirates has its eye on building a new nuclear power plant with the help of an agreement inked with the Bush administration. And Asian countries never stopped—with 35 new reactors presently under construction. China alone has accelerated its program to build five in the next few years, including the first AP-1000 to be built anywhere in the world. "It's not only ambitious, it's ambitious on a global scale," Heymer says.

It will be difficult for would-be builders of nuclear power plants to get the items they need, like the enormous steel containment vessels that shield a nuclear reactor. At present, only one company in the world—Japan Steel Works on the island of Hokkaido, which also makes coveted samurai swords—can handle the 600-ton steel ingots needed to make the cylindrical container uniformly strong.

Although other companies, such as Doosan Heavy Industries in South Korea and AREVA in France, are ramping up their ability to do so, it will be years before they match Japan Steel Works's capability. That means new nuclear power plants won't be coming online very quickly.

"If climate is a problem, we need the most solution per dollar and the most solution per year," Lovins says. "We can get two to 10 times more coal displaced per dollar buying stuff other than nuclear. Every time I spend a dollar on an expensive solution I forgo a lot more that I could have bought of a cheaper solution."

Nuclear decline?
Nuclear power currently generates roughly 20 percent of U.S. electricity—more than 806 billion kWh in 2007. In order to simply maintain that portion of the generation mix, 35 new reactors would have to be built in the next few years, according to Tom Williams, a spokesman for Duke Energy.

Dale Klein, chairman of the NRC, puts that figure at 50 new 1,000-megawatt plants in the next decade or so. "And not even the most enthusiastic pronuclear people think that there will be 50 new plants generating electricity anytime soon," he said in a speech in January 2008.

An ongoing effort to build a Gen III+ nuclear reactor in Finland—the so-called evolutionary pressurized water reactor, or EPR, from AREVA—is already three years behind schedule and around $2 billion (1.5 billion euros) over budget, initiating arbitration action between the Finnish utility and the French nuclear power plant builder over who will pay the extra cost.

That means nuclear power will likely not play a large role in combating climate change, at least in the near-term. And if that's the case, then critics say there's no point to resurrecting it. "The riskiest kind of plant you can build is one that's never been built before and that's what all of these are," says Michael Marriotte, executive director of the Nuclear Information and Resource Service and longtime antinuclear activist. "Spending enormous amounts of money on nuclear power is the slowest and least efficient way to close coal plants or prevent new ones from being built."

Further, energy conservation efforts in the past meant that the U.S. ended up consuming the same total amount of energy in 1986 as in 1974 and, with the Obama administration expected to focus on such efficiency programs, the need for new nuclear power plants could be obviated again. "If you are the utility executives, you have climate change in your mind, but it's not necessarily the driving force," says Westinghouse's Gilbert. "The driving force is what's economical to build for new generation."

But there are other considerations that may stand in the way of any future fissioning. "We are not going to fight with our neighbors about building a new plant. And another primary criteria, there has to be some resolution to the high-level waste issue," says Craig Nesbit, vice president of communications for Exelon. "We don't think it's appropriate to build another plant in another community knowing that we are saddling that community for an indeterminate amount of time with high-level waste."