NASA is running out of plutonium. The space agency uses Pu-238 to fuel many of its deep space missions, including New Horizons, Voyager, the Curiosity rover, and the Mars 2020 rover. These long-lasting batteries were the byproducts of nuclear weapons manufacturing, and now that the world is making less of those, NASA’s stockpile of plutonium fuel is dwindling.
In December, the U.S. made its first fresh plutonium in almost 30 years. It was a relatively small amount–1.8 ounces, compared to the 8.8 pounds that a rover like Curiosity requires–but it’s a start. In 2016, the Department of Energy (DOE) aims to produce 12 ounces of the stuff.
At today’s meeting of NASA’s Outer Planets Assessment Group, Rebecca Onuschak from the DOE explained how the government plans to get better at making plutonium for deep space missions.
For starters, they’re going to upgrade a lot of the equipment that’s being used to produce Pu-238 at the Los Alamos, Idaho, and Oak Ridge national laboratories. This includes new furnaces, thermal vacuum chambers, and hot presses.
Although the DOE used a new process to manufacture its plutonium, some of the hot presses they’re using were built in the 1950s, Onuschak said, joking that they’re “vintage.”
Upgrading the equipment will make creating plutonium safer and more reliable.
The agency is also looking at new ways to improve and scale up the process. “We’re trying to make it as nimble as it can be,” said Onuschak.
Right now the DOE is looking into a new process that could potentially double their plutonium output, while creating a higher-quality product. It’s also cheaper. The secret appears to be in using “a pure neptunium dioxide pellet clad in zircaloy.”
Over the next year or so, DOE will figure out how to make these pellets, then bombard them with radiation to see if they work as expected.