Faced with the competing threats of global warming and a looming energy shortfall, federal regulators are contemplating whether another 20 years of service can be squeezed out of the nation's aging nuclear power plants without compromising safety.
Many say they believe that the 104 nuclear reactors operating in the U.S. will be forced to retire faster than industry can replace them, unless regulators act to extend their lives to 80 years from the current 60-year maximum. The discussion is of particular interest in Maryland, where Constellation Energy Group owns two aging nuclear reactors and is considering whether to build a third to meet the state's growing energy needs.
Though it will be years before any licenses expire, the debate has urgency because utilities are making decisions that will affect how many nuclear plants will be built during the next 20 years.
The issue might prove critical to efforts to keep the lights on without adding polluting greenhouse gases to the atmosphere. Nuclear plants produce 20 percent of the nation's energy supply but account for more than 70 percent of the electricity from all sources classified as emissions-free.
The plants also dispatch some of the cheapest electricity to the power grid, making them critical to keeping the nation's utility bills in check, proponents argue.
"The practical reality is that if those plants are determined not to be viable for an additional 20-year operating cycle, then we need to start building new generation today," said Alex Marion, executive director of operations and engineering for the Nuclear Energy Institute, the industry's trade group. "Twenty percent of the nation's capacity is a tremendous amount of energy to make up with non-nuclear facilities."
The concern is acute in Maryland, where state officials worry about a power shortfall in coming decades. The operating licenses for the two reactors at the Calvert Cliffs nuclear station in Lusby - the backbone of the region's power supply - are set to expire in 2034 and 2036, respectively. Nationwide, the first plants will hit mandatory retirement under current regulations as early as 2029.
That's a blink of an eye, given that it could take 10 years to come up with regulations for extending the licenses. Also, experts point out that it can take a decade to plan, build and license a new plant. Some 30 nuclear projects are proposed, but no one has committed to construction.
There is widespread concern that the industry lacks the financial backing, infrastructure and manpower to replace all of the existing nuclear plants before time runs out on their current licenses. The infrastructure required to build new plants in the U.S. largely disintegrated after the 1979 Three Mile Island accident raised concerns about the safety of nuclear power.
Yet industry analysts say they expect demand for nuclear energy to increase if Congress reaches agreement on legislation placing limits on carbon emissions - a move that would spur demand for emissions-free generation. Congress also included a package of tax breaks and loan guarantees in the 2005 energy bill.
"Policymakers may come back and say, `We need you guys to build many, many more plants at a higher rate of construction,'" said Gary Vine, an executive director in the nuclear section of the Electric Power Research Institute. "When that happens ... you're going to probably find our ability to build new plants just to support U.S. energy security is going to be well beyond our capacity."
The Energy Information Institute, the statistical arm of the Energy Department, estimates that demand for electricity will grow by 40 percent by 2030 - about the time nuclear licenses start to expire. The industry would have to build up to 300 conventional plants by then to keep pace. More will be needed if existing nuclear facilities are phased out.
To buy time, the Nuclear Regulatory Commission is teaming with scientists and engineers to study what kind of maintenance and equipment monitoring are needed if nuclear plants are made to last 80 years. The agency said the effort is in the planning phase, but it has a workshop on the topic scheduled for February.
Reactors require extensive monitoring and upkeep as they age. Major components, such as steam generators, can break down, costing hundreds of millions of dollars to replace. One major focus will be whether reactor vessels - massive structures that contain the reactor core and coolant - can stand up to intense pressure, heat and radiation for another 20 years. Reactor vessels are exposed to significant neutron radiation over time, which can cause the metal to become brittle.
"The technical question is how long can they go," said Revis James, director of EPRI's energy technology assessment center. "I don't believe anyone has ever done that study or calculation."