Southern Co. moves closer to advanced reactor technology

By Kristi E. Swartz | 08/23/2016 07:00 AM EDT

Southern Co.’s nuclear unit and X-energy LLC are taking another step toward commercializing next-generation nuclear reactor technology, the companies said yesterday.

Southern Co.’s nuclear unit and X-energy LLC are taking another step toward commercializing next-generation nuclear reactor technology, the companies said yesterday.

The companies have signed a memorandum of understanding to commercialize and use X-energy’s high-temperature gas-cooled reactor. The MOU moves forward on efforts to develop advanced nuclear technology to keep nuclear as a viable electricity source.

Southern Nuclear and X-energy will combine research and nuclear reactor operating experience to develop an advanced nuclear design, a Southern Nuclear spokeswoman said. Southern Nuclear wants more options for nuclear energy and considers X-energy playing a significant role in doing that, Jessica Nissenbaum said in an email to EnergyWire.


"Advanced reactor technologies have the potential to cost-effectively achieve very high levels of performance," Nissenbaum said.

Their efforts already have the backing of the federal government. The Energy Department earlier this year awarded Southern and Maryland-based X-energy up to $80 million to develop advanced nuclear technologies that would be commercially ready by 2035 (EnergyWire, Jan. 20).

X-energy’s so-called Xe-100 reactor technology has key differences from traditional reactors, including fuel, temperature and cooling requirements.

The reactors operate on "pebble" fuel: 200,000 dense pebbles, each filled with 24,000 tiny particles. The way the pebbles are packaged makes the reactor safer than traditional ones, said Martin van Staden, X-energy’s vice president of nuclear development.

The reactors don’t have to stop operating during a refueling, he said.

The reactor makes energy — and steam — at a much higher temperature, which means it can operate more efficiently. It also doesn’t require water to cool it, removing any chance of a nuclear meltdown, van Staden said.

"In the worst-case scenarios, the reactor will shut itself down and dissipate the heat naturally to the environment," Staden told EnergyWire in an interview.

What may be most important is the reactor’s ability to run as baseload generation or "load follow," which means it can adjust its power output as electricity demand fluctuates throughout the day. This separates next-generation reactor technology from current reactors and is a key point as renewable energy starts to play a greater role in Southern’s generation mix.

The Xe-100 reactors would be able to ramp up or down their power output in conjunction with how much solar, wind or other renewables are on the grid at the time, working in tandem with those intermittent resources.

Staden said the companies may be able to develop and use the Xe-100 reactors around the 2027-2030 time frame. This is because they are building on previous work on next-generation reactors that started more than a decade ago.

The Energy Policy Act of 2005’s "Next Generation Nuclear Plant" program actually called for a prototype high-temperature, gas-cooled reactor to be ready to go by 2021.

"Those are the benefits that we are building on," he said.

Southern has been an unwavering proponent of nuclear and is one of two utilities in the United States currently building reactors from scratch. But despite the company’s enthusiasm, the nuclear industry is in flux largely because of a glut of cheap natural gas and, in some markets, wind power.

The chief executives of Atlanta-based Southern and Birmingham-based Southern Nuclear have been outspoken about pushing the industry forward. Southern CEO Tom Fanning points to the Generation IV technology as significantly moving the industry forward beyond other developments such as small modular reactors, he has said.

Southern Nuclear CEO Steve Kuczynski also has challenged the nuclear industry to produce 40 percent of U.S. electricity by 2040. The emissions-free power would be a chief way for utilities to operate in the future under carbon constraints, even with U.S. EPA’s Clean Power Plan currently frozen in court.