One factor is performance. The output of the 104 nuclear power plants (N.P.P.s) in the U.S. has improved dramatically, to a capacity factor (actual output divided by design output) of 92 percent in 2007 from about 70 percent a decade ago – and that has meant favorable economics for the operators. As measured by numerous “performance indicators,” operating safety has steadily improved. No U.S. plant worker or member of the public has ever been injured or killed by an accident caused by nuclear power. Another key factor is that nuclear power is an emissions-free source of electricity. About 70 percent of all such electricity in the U.S. is generated by nuclear power. And finally, the newest reactor designs provide even greater improvements in construction and operation economics, reliability, and safety.

What are the indicators of this renaissance? Since the beginning of 2006, 17 U.S. utilities have announced plans to file applications with the U.S. Nuclear Regulatory Commission (N.R.C.) to build as many as 33 nuclear plants. Applications for 15 N.P.P.s have been filed with the N.R.C. and are already under review. Numerous utilities have placed manufacturing orders for major N.P.P. components. And two utilities have signed engineering, procurement, and construction (E.P.C.) contracts for four nuclear plants, the first new orders in this country since 1978. Worldwide, 35 new N.P.P.s are currently under construction, most notably in China, India, Russia, South Korea, Pakistan, and Japan, and many other countries have announced major new construction programs.

The U.S. Department of Energy (D.O.E.) forecasts that by 2030 U.S. electricity demand will increase by 30 percent. Thus, just to maintain the same electricity generated nuclear power would require about 30 new N.P.P.s. Globally, about 17 percent of all electricity is generated by the 440 nuclear plants now in service. But the worldwide demand for electricity is growing even faster than in the U.S. This is due to three factors: the world population growth rate is about three times greater; Third World countries are industrializing and improving their standards of living; and new technology powered by electricity is increasingly available. United Nations projections indicate that the world’s electricity demand will double or triple by mid-century. Thus, just to maintain the same worldwide amount of electricity from nuclear power would require 1,000 (or more) new N.P.P.s

The nuclear renaissance in the U.S. began with the existing fleet of N.P.P.s. During the past 15 years, power up-rates and capacity factor improvements have increased the fleet’s power output by the equivalent of 26 new 1,000 megawatt plants. Additional power up-rates of up to 15 percent for 11 additional plants are currently under N.R.C. approval review. And the N.R.C. has approved 20-year operating license renewals for 49 N.P.P.s. (N.P.P.s are initially licensed to operate for 40 years.) Another 17 renewal applications are under N.R.C. review, and letters of intent to renew for an additional 25 N.P.P.s have been submitted. It is expected that the licenses of all 104 operating plants will be extended for 20 years, and discussions are underway regarding conditions for an additional 20-year renewal.

Compared to the current fleet, each new U.S. plant will have advanced designs. These include new fabrication and construction techniques, digital control and safety systems, emergency systems with higher reliability, greater volumes of emergency cooling water, and capability to use advanced nuclear fuels that produce more energy and less waste. One commonality with the currently operating plants is that their reactors are cooled by water under high pressure at about 300o C. This technology was originally developed for the U.S. Navy’s nuclear-powered submarines, called Advanced Light Water Reactors, or A.L.W.R.s. It is generally believed that all commercial reactors to be built worldwide during the first half of this century will be some type of A.L.W.R.

The five new designs considered for use in the U.S. include the Advanced Boiling Water Reactor (A.B.W.R.) by General Electric/Hitachi; the European Pressurized Reactor (E.P.R.) by Areva; the AP-1000 by Westinghouse; the Advanced Pressurized Water Reactor (A.P.W.R.) by Mitsubishi; and the Economical Simplified Boiling Water Reactor (E.S.B.W.R.) by General Electric/Hitachi.

The second distinction involves how the design achieves higher emergency system reliability, specifically of the emergency core cooling system (E.C.C.S.). The A.B.W.R., A.P.W.R., and E.P.R. are called “evolutionary” designs. The E.C.C.S. has higher reliability because it has more parallel systems (power supplies and water-delivery trains) than current designs, although they are similar to current designs. The AP-1000 and the E.S.B.W.R. are called “passive” designs. The E.C.C.S. delivers water by gravity-feed systems, which involve fewer electrically powered pumps and valves. Reliability mathematics demonstrates that each approach produces a similar improvement in E.C.C.S. reliability, compared to current E.C.C.S. designs.

So what are the major challenges to this nuclear power renaissance actually happening? There are four near-term challenges. Perhaps the foremost is to have sufficient labor, both skilled and degreed, to make it happen. During the last three decades or so, nuclear power has not been an attractive career objective. Along with many other heavy manufacturing industries in the U.S., nuclear power has an aging workforce. Over the last several years, estimates have been that 70 percent of this workforce would retire within the next 5 to 10 years. The recent slowdown of the overall U.S. economy has caused this bow wave to continue to move out as retirements are postponed.

Notwithstanding the retirement situation, skilled labor shortages – of electricians, welders, pipe-fitters, machinists, radiation protection technicians – already confront the nuclear power industry. Numerous trade schools shut their doors during the past decade. Consequently, many utilities have established their own training programs, usually in collaboration with local community colleges. Another shortage involves the nuclear engineers needed to design and operate the plants. Undergraduate enrollments in nuclear engineering reached a low of about 700 students in 1998. Today, the number of universities offering this degree is half what it was 20 years ago. Another traditional source, the U.S. Navy, produces about 60 percent fewer former enlisted personnel as it once did.

Fortunately, the situation is improving rapidly. Programs to train new personnel in various labor skills are becoming more widely known and attended. Last fall, university enrollments in nuclear engineering were more than double their number in 1998, and several schools have started or are considering new degree programs. The driving force producing these results is the aggressive hiring campaign being conducted by the reactor vendors cited above, the N.R.C., and the utilities. All of those entities are trying to hire hundreds of new engineers to fill job openings and this hiring campaign is likely to continue.

The second near-term challenge is to re-establish the nuclear industry infrastructure in the U.S. to provide all of the structures, systems, and components that N.P.P.s need. The largest are the thick-walled steel vessels that house the nuclear reactors, the huge heat exchangers (steam generators) that turn water to steam, and the piping that connects these components. The techniques used to manufacture the current fleet of operating reactors involved bending thick metal plates and welding them to form vessels or piping. The design of all A.L.W.R.s has replaced this technique with ultra-heavy forging. Major sections of a vessel, or a complete length of pipe (including all connecting nozzles), are formed from a single metal billet with multiple pressing and boring steps. Unfortunately, there is no U.S. facility that can fabricate these very large forgings. The only facilities are in Japan, France, South Korea, and Russia; China has plans to build three heavy-metal forging factories.

Another infrastructure issue concerns the manufacture of pumps, pipes, valves, controllers, and other components. The quality of these components’ manufacturing processes and products must be certified by an N-stamp from the American Society of Mechanical Engineers. A typical A.L.W.R. requires a large quantity of these components: about 2,500 valves, 250 pumps, 25,000 feet of pipe, 225 miles of electrical cable, and 90,000 electrical devices. During construction of the current U.S. fleet of operating N.P.P.s, about 600 companies held an N-stamp; today only about 100 companies are so qualified.

The Nuclear Energy Institute, an industry trade and policy organization based in Washington, D.C., conducted three manufacturing workshops this year in hopes of stimulating U.S. industry to re-establish this lost manufacturing capability. The response during these workshops has been encouraging, but it is too early to tell how successful they will be. Meanwhile, reactor vendors and utilities have placed overseas orders for heavy components, and it is expected that most for the first new plants will come from foreign sources.

The third near-term challenge is financing the cost of constructing a new N.P.P., estimated at about $5 billion. The largest U.S. utility currently operating N.P.P.s has a book value of about $17 billion, and most are much smaller. Thus, committing to a new N.P.P. is literally “betting the company.” To reduce this risk, the Energy Policy Act of 2005 provides three key incentives: a production tax credit of $18 per megawatt-hour for the first 6,000 MW of new N.P.P.s; risk insurance against delays in commercial operation caused by licensing or litigation outside a utility’s control; and loan guarantees up to 80 percent of the project cost. (Note that these incentives are not unique to the nuclear industry. Similar ones are available to other power projects that reduce emissions.)

The fourth near-term challenge is the regulatory uncertainty associated with licensing a new reactor. The N.R.C. has streamlined its process since the last nuclear plants were licensed. Under the new process, the regulatory approval to construct and operate a new plant is issued, based on a pre-approved design (previously certified by the agency) before construction begins and significant expenditures are made. This should help preclude the outrageous cost escalations experienced during the regulatory delays in issuing an operating license that followed the construction of many current reactors. However, the process is untested. Positive experience with the first several applications, including satisfactory public involvement, is required to build confidence and reduce the level of uncertainty.

Over the long term, three other challenges must be considered. First, nuclear plants must continue to operate with the excellent safety record demonstrated over the past two decades. Second, a long-term method to dispose of highly radioactive waste must be implemented. Third, there must be adequate security to preclude diversion of materials that could be used for nuclear weapons (so-called “proliferation”). It is widely acknowledged in the industry that the first of these, operating safety, underlies all other considerations of nuclear power. The second and third challenges are closely related.

The form and volume of highly radioactive waste can be much easier to dispose of by extracting it from used nuclear fuel. This process, called reprocessing, allows the remaining nuclear fuel to be recycled to obtain its residual energy content (about two-thirds after its initial operation in a reactor). During reprocessing, security must be adequate to preclude materials diversion; currently this is accomplished using physical deterrents (frequently referred to as “guns, gates, and guards”). Outside the U.S., France, England, Japan, and Russia reprocess and recycle commercial nuclear fuel for their own reactors and under contract for other countries. China has reprocessing/recycling facilities under construction. Although the U.S. formerly had such facilities, none currently exist at commercial scale.

As for waste disposal, in response to the 1982 Nuclear Waste Policy Act the federal government selected a deep geologic repository at Yucca Mountain in Nevada. (Highly radioactive waste from defense facilities is disposed of in the Waste Isolation Pilot Project in New Mexico, which has been operating successfully for eight years.) On June 3, 2008, the D.O.E. submitted an application to the N.R.C. that would allow it to operate the Yucca Mountain repository. Initial operation is forecast to begin as early as 2017. Almost all used nuclear fuel is currently stored at N.P.P. sites.

Although the Yucca Mountain repository is designed to dispose of used fuel transferred directly from reactors, it would be more efficient to reprocess the used fuel and only dispose of the relatively low volume of highly radioactive waste. This conclusion is becoming widely accepted.

The D.O.E. is also developing reprocessing and recycling methods that would be inherently proliferation-proof. Under the Advanced Fuel Cycle Initiative the agency developed methods in which elements such as plutonium (which would be potentially attractive for diversion) are always combined with other elements, which would make them useless for nuclear weapons. The results of this initiative are now a cornerstone of the Global Nuclear Energy Partnership. The U.S. and other countries that currently have reprocessing/recycling capability would provide this service, thus reducing the volume of highly radioactive waste, recovering residual energy content of used nuclear fuel, and establishing security against proliferation.

Looking to the future beyond A.L.W.R.s, the D.O.E. is leading an international program involving 10 countries to design the next generation of reactors. The objective of these Generation IV reactors is to have improved economics, safety, and security. Improved economics are expected, due to much higher operating temperatures (about 1000o C) producing greater thermal efficiency. Increased safety is expected using meltdown-proof materials (in some designs). Improved security is expected using proliferation-resistant fuels and fuel reprocessing/recycling methods. In addition, the Generation IV reactors include designs that can actually produce more fuel than they consume, the so-called “breeder reactors.”

Clearly, whether any of these designs is ever considered for commercial application depends on the success of the renaissance beginning today with A.L.W.R.s. .

William E. Burchill is the president of the American Nuclear Society. He is also adjunct professor and retired head of the nuclear engineering department at Texas A&M University.