Oak Ridge National Laboratory: Isotopes – Welding advances

A better way of welding targets for Oak Ridge National Laboratory’s plutonium-238 production has sped up the process and improved consistency and efficiency. This advancement will ultimately benefit the lab’s goal to make enough Pu-238 – the isotope that powers NASA’s deep space missions – to yield 1.5 kilograms of plutonium oxide annually by 2026.

ORNL began using an orbital welder inside a protective glovebox for the weld that closes the hollow tube containing neptunium feedstock – the last step before these targets are irradiated in ORNL’s High Flux Isotope Reactor to produce Pu-238. (Watch video)

The new computer-controlled orbital welder produces welds that do not require hand finishing, thereby shortening the time to complete welding jobs from a week to about a day.

“The time saved really adds up as we work toward our production goals,” said ORNL’s Robert Wham. Plutonium oxide is the power source for Perseverance, NASA’s Mars rover.


ORNL welder Devin Johnson uses a new orbital welder to seal a hollow target in a glovebox in the lab’s Radiochemical Engineering Development Center. The new welder makes a clean seam on the metal target, eliminating the need for hand-finishing afterward. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy
ORNL welder Devin Johnson demonstrates a new orbital welder that will make the lab’s Pu-238 production program more efficient, by reducing the amount of time it takes to ready hollow feedstock targets for irradiation. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy
The orbital welder makes a clean seam on hollow targets, eliminating the need for hand-finishing and reducing the amount of time staffers spend in the glovebox. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy