Generating more power
Nuclear plants might be run past their allowed maximum
By Paul Adams
October 27, 2007
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."
Critics of the industry say the stakes are high for regulators. Experience has proven that mistakes can be made even when the industry is trying to take initiative. The most recent example involved the Davis-Besse nuclear plant near Toledo, which had to be temporarily shut down in 2002 after technicians discovered that acid used in cooling water had almost eaten through the reactor vessel's lid.
Early evidence of the corrosion had been detected a few years before, but not acted upon until it grew worse.
"The downside is there have been a number of aging-related failures, because, despite everybody's best efforts, we've missed them," said David Lochbaum, director of the nuclear safety project for the Union of Concerned Scientists, an advocacy group that follows nuclear issues.
Lochbaum, who has been critical of federal regulators, said the NRC has limited resources and can't watch over every worker's shoulder or keep track of every piece of equipment.
But regulators have been down this path before. U.S. nuclear plants were originally given 40-year licenses to operate. The NRC published regulations in the mid-1990s allowing plants to operate another 20 years if owners met strict safety requirements designed to catch age-related mishaps.
Constellation's Calvert Cliffs plant was the first to do so in March 2000. A new nuclear reactor at Calvert Cliffs under consideration would cost an estimated $4 billion or more. Still, many say energy from both the new and old reactors will be needed to meet the state's energy needs without adding pollution.
Michael J. Wallace, executive vice president of Constellation Energy, said the company would be interested in extending Calvert Cliff's operating license another 20 years but will need to weigh the economics when the time comes. Maintaining a nuclear plant is like car care - at some point, it becomes cheaper to buy a new one rather than keep fixing the old model.
"The economics are pretty compelling when, for $20 [million] to $30 million, which would be the typical cost of the license extension, you can get a 1,000- to 1,100-megawatt nuclear plant that can run for 20 years," said Per F. Peterson, a nuclear engineering professor at the University of California, Berkeley. One megawatt is roughly enough to power 1,000 average homes.
Rising electricity prices have made existing plants highly profitable for the industry. Peterson said there are few components inside a plant that can't be replaced economically.
The exception would be the reactor vessel. Peterson said the size and cost likely would make replacing a vessel impractical. But few say it will come to that.
"We have done a lot of research on reactor vessel toughness," said Vine, the EPRI nuclear expert, "and I think the belief we have now, both in the industry and on the NRC side, is that most of these vessels are OK for well into 80 years and beyond."