After a three-decade hiatus, work is finally under way on a new wave of reactors thanks to government funding – but China is already way ahead.

YOU could be forgiven for thinking a new era of nuclear energy is under way in the US. On 11 March, crews at the Virgil C Summer power plant in South Carolina completed a 51-hour marathon of pouring concrete. Three days later, in Burke County, Georgia, another concrete base was completed.

The two reactors that will sit on these bases will be Westinghouse AP1000s. Like older models, they will use uranium fission to heat water and drive a turbine, but these reactors will be smaller, simpler to build, and each will add more than 1100 megawatts of capacity to the region’s power grid when they come online in 2016 or 2017 – without emitting carbon dioxide.

They will be the first new reactors on US soil in over three decades. Besides the two reactors in progress, two more are planned – one at each plant. And work has resumed on a half-built reactor, Watts Bar 2 in Tennessee. It could be connected to the grid by 2015.

“There’s no question it’s a big deal,” says Neil Wilmshurst of the Electric Power Research Institute in Palo Alto, California. “There were no new plants being constructed for decades, and now there is a new wave of building going on.”

What seems like a sudden rush back to nuclear was actually put in motion years ago, when US utility companies began to pre-empt the possibility of government-mandated cuts in carbon emissions. But to get construction under way, the firms needed a big helping hand from the government. As part of President Barack Obama’s goal of promoting clean sources of energy, he guaranteed $8.3 billion in federal loans for the reactors, which helps spread the massive cost of the projects.

All four new plants will be AP1000s. These reactors are descendants of the ones that have been in service since the middle of the 20th century. However, they have major safety upgrades, new pump designs and more straightforward circulation systems. More exotic designs remain on the horizon, such as reactors powered by thorium fuel, but the AP1000 and other more conventional designs are important for one simple reason: they are being built. That means adding reliable, low-carbon energy to the US grid on a scale that other technologies can’t yet match.

Whether the construction signals the start of a US nuclear energy boom remains to be seen. Reactors are expensive and fossil fuels are cheap enough that utility companies are nervous about undertaking such long, costly projects. “It’s a bet-the-company proposition,” says Wilmshurst.

That’s not the case in China, where massive government backing has allowed construction there to race ahead of the US. Across China, 28 reactors are being built, many of them AP1000s, including one nearing completion at the Sanmen Nuclear Power Station in Zhejiang Province. It will become the first operative AP1000 if it comes online later this year as planned.

Mitchell Singer of the Nuclear Energy Institute, an industry advocacy group in Washington DC, says the comparatively slow take up of the AP1000 could be down to its unproven nature. “Someone’s got to take the first step and blaze the trail into the wilderness,” he says. “In the next decade, once plants come online successfully, that will give confidence to others to follow with their own projects.”