Solving the `Boiling Crisis' Would Boost Nuclear Plants' Power

(Bloomberg) -- You thought you knew how water boils? Think again.

Turns out that there are gaps in the scientific understanding of this phenomenon. Learning more about how heat is transferred could help safely boost the output from nuclear power plants by as much as 20 percent, according to a paper Friday in the journal Physical Review Letters.

“It’s a very complex phenomenon,” Matteo Bucci, an assistant professor of nuclear engineering at Massachusetts Institute of Technology, said in a statement. “We talk about an energy revolution, a computer revolution, nanoscale transistors, all kinds of great things. Yet, still in this century, and maybe even in the next century, these are all limited by heat transfer.”

The key is something called the “boiling crisis.” Think about a pot of water. As the metal heats up, so many bubbles can form on the hot surface that they coalesce into a sheet of vapor. That can block some heat from transferring from the pot to the water. In nuclear reactors, it can block heat from moving from the fuel rods to the cooling water, potentially damaging critical components, said Bucci, co-author of the paper.

“The power rating of power plants is limited by the boiling crisis,” he said in an interview. “We operate reactors in such a way that we keep the boiling crisis far away.”

If scientists had a better grasp on this phenomenon, they could model surfaces with different materials or textures that minimize the interaction between bubbles and avoid the boiling crisis. This could potentially lead to reactors that run at higher temperatures and produce more power.

Nuclear power plants are facing increasing cost pressure from cheap natural gas and renewables. A technological advance that could let operators get more output from reactors would help them remain competive.

Bucci said the required retrofits would likely be too costly to implement. But for new reactor designs, “the sky’s the limit.”

©2019 Bloomberg L.P.