...the improvements are expected to result in units that are one-third the size of their sisters, units Nos. 1 and 2. The passive systems use gravity, rather than pumps, meaning that 80% less safety-related piping is needed and, overall, 35% fewer pipes.
With some small exceptions, standardized design means the AP1000 that Shaw/Westinghouse is building in China will be the same reactor the joint venture will build at Plant Vogtle; further, the pressurized reactor that Areva is building in France is the same as the reactors it built in Finland and China.
Those designs, in varying degrees, all use modular construction, which is another big improvement.
“The concept of module construction did not exist in the past,” Jones says. “You had to have significantly more resources in one locations. There were physical limitations. It did not lend itself to being efficient,” he says, referring to the last round of nuclear builds.
With modular construction, many of the unit’s pieces are fabricated in a factory, then shipped by rail, truck or boat to the site of the plant.
Shaw has built a module facility in Lake Charles, La., and earlier this year began building pieces, called subsections, that eventually will become 1,000-ton modules at Plant Vogtle. The flat subsections will be about 10 ft wide, 68 ft to 77 ft long, and 30 in. to 48 in. thick; they will be shipped by rail to the plant. The subsections are fabricated as flat panels, L-sections and T-sections to fit the configuration of the final module. A temporary building tall enough to fit a 747 jetliner has been erected at Vogtle to assemble the modules.
When complete, the AP1000 modules will house auxiliary and containment buildings, steam generator compartments and a refueling canal within the containment vessel.
Modular construction provides more than just the expected efficiencies of modularization. In nuclear construction—where quality is king—the ability to build something in a controlled environment is considered a precious commodity.
“It’s critically important to build as much in the factory as possible,” Tye says. “Modular is highly critical.”
|Japan, Slovak Republic, Ukraine|
|Iran, Pakistan, United States|
|SOURCE: INTERNATIONAL ATOMIC ENERGY AGENCY|
Adding more predictability into the new round of nuclear builds is the way the NRC has revised the way it licenses and authorizes plants. The NRC is pre-approving designs for reactors and then, based upon those standardized designs, will issue a combined construction and operating license for a site. In the last round of builds, the NRC would issue a construction license, but—depending upon public outcry or a Three-Mile Island-like disaster—it could require utilities to redesign their reactors in the middle of construction. The NRC would issue an operating license only after the plant was built.
Under the new regime, work that has been done must undergo and pass an extensive set of inspections, tests, analyses and acceptance criteria, or ITAAC, that have been developed by the NRC and the plant developers. The set of ITAACs ensure the work is done the way the designs indicate it should be completed, says Richard Laura of NRC’s division of construction inspection and operational programs. The AP1000 is expected have about 1,000 such measures, while General Electric’s Economic Simplified Boiling Water Reactor will have closer to 2,000 measures.
ITAACs can include something as simple as ensuring a fuel-handling machine’s interlock works or as complex as making sure the engineering analysis meets all the applicable codes, says Laura. The NRC will directly inspect about 30% of all those ITAACs and verify that all the ITAACs are met.
Laura says the method is a lot more structured than the last round of nuclear plants, when inspectors “tried to catch what they could.”
While standardized design, modular construction and prelicensing are expected to reduce many of the headaches surrounding nuclear construction, they won’t eliminate all of them.
In Georgia, as Shaw and Southern began preliminary work on the foundation for the units, they discovered the soil was not as stable as core tests indicated. As a result, an unrevealed cost has been added for mining and engineering 1.3 million cu yds of soil at the Vogtle site. More than 180 pieces of heavy equipment are running through 250,000 gallons of diesel fuel a month, largely to find soil that meets NRC standards. “In a project as massive as this, there are going to be gives and takes relative to assumptions,” Jones says. “In some cases, it will work to your favor, and in some cases, it won’t. That’s just part of project management.”
Adding to the typical contingencies of project management for such multibillion-dollar projects is the lack of U.S. nuclear knowledge, talent and suppliers.
“The dearth of experienced nuclear engineers and construction workers is a key factor that also increases costs,” according to Standard & Poor’s. “The degree of training and productivity of workers is uncertain, requiring companies to incorporate additional contingencies in cost and schedule budgets.”
Utilities, contractors and the Nuclear Energy Institute, an industry group based in Washington D.C., have been attempting to remedy the workforce and supplier problems.
Most critical is the lack of a manufacturing base in the U.S., which has withered since the last round of new plants, says Bill Labbe, manager of nuclear power services for Lowell, Mass.-based TRC Solutions, an engineering and consulting firm that works with many U.S. nuclear plants.
The number of manufacturers certified with an “N- stamp” from the American Society of Mechanical Engineers shrunk from a high of about 800 to about 150 a decade ago, Candris says. Today, the industry is again close to 800 N-stamps but with much more global sourcing, he says.
While the recession has resolved concerns that companies won’t be able to find the 3,000 to 4,000 workers needed to build each plant, there is still a shortage of craftspeople, particularly qualified nuclear welders, says Carol Berrigan, senior director of industry infrastructure for NEI.
Once workers are hired, they must become familiar with the higher quality of work required for nuclear construction. Companies working in the nuclear industry say the culture of nuclear safety has been ingrained after the decades of work each has done in the industry.
“Everyone has to realize we’re building to a different standard,” says Shaw’s Bernhard. “It matters if it’s absolutely correct.”
That sentiment is also true of the nuclear industry in the U.S. as utilities, regulators and the financial community watch to see whether the first round of plants can be built “absolutely correctly.”
“The first company has to do it right and demonstrate to the financial community that these things can be done on a consistent basis. I think that is a key to the renaissance,” says Labbe.
Jones, who has the weight of the nuclear renaissance on his shoulders, isn’t worried about dashing his dreams or the dreams of the industry.
“I see it as an opportunity,” he says. “It’s bigger than any one person—it’s much bigger than any one organization. We are changing the dynamic of our electricity needs and providing a solution that will be viable for our country.”