Small modular reactors (SMRs) are nuclear generating units that are about the size of railroad cars and provide about one-tenth to one-fourth the power of full-size reactors. As a result, they...
The Incredible Shrinking Reactor
Small is beautiful for nuclear developers.
underground, and thus easier to protect. Likewise, with the mPower design, used fuel would be stored underground in the containment structure for the entire life of the plant. The mPower reactor is designed to be refueled about every four-and-a-half years, he says, which involves replacing the entire core.
Such a refueling cycle offers its own potential benefits. “If the refueling cycle is every four to five years, and if four of these units are in place at one site, then each year one of the units would come off-line to refuel, while the other three continue to generate power,” says Todd Schneider, a spokesperson for FirstEnergy. “This would be an alternative to having to take one huge unit off-line, and we see this as very beneficial.”
Mowry says the value proposition for mPower comes down to three things. “One is cost certainty, the second is schedule certainty, and the third is affordability,” he says. “You didn’t hear me say anything about technology. That is, we aren’t about a science project. We are in business to repackage the best of proven technologies and make it more affordable by creating an incremental nuclear option. You don’t have to bet your company to deploy a nuclear plant.”
A key feature of SMR projects involves flexibility in siting and development.
“What got us interested was that, as we look into the future, we realize that there may be situations where we don’t need a large amount of new power at one time,” Bhatnagar says. “Rather, we may need small increments of power over multiple years.” The idea of having individual modules that TVA could implement over time seems like a good option.
While some utilities might be interested in SMR technology as a way to more easily create greenfield nuclear sites, utilities and vendors alike see substantial opportunities to install them at existing coal or nuclear facility sites. “Our fossil fleet is fairly old—about 45 to 47 years old,” Bhatnagar says. “As we look into the future, especially in terms of some of these smaller units, there could be an opportunity to repower these fossil fuel sites by installing new reactors and new turbine combinations.” And, of course, he adds, these sites already will have water, transmission, and other infrastructure. “This strategy could help to reduce our carbon footprint over time,” he says.
Replacing older coal-fired capacity might become a sweet spot in the market for SMRs. “These locations already have cooling water available, as well as substations and transmission lines,” Mowry says. He also sees potential for the units on existing brownfield nuclear sites, which, for example, might have been designed for four large units, but have only two up and running. “Utilities have the opportunity to incrementally build these out in bite-sized chunks,” he says. “Then, once they get revenues from the first installation, they can begin work on the next.”
Still another placement option and benefit, according to Westinghouse’s Anness, is that certain portions of the grid are incapable of handling more than a few hundred megawatts of power at one