ORNL Succeeds in Producing 50 Grams of Plutonium-238

ORNL Succeeds in Producing 50 Grams of Plutonium-238

Researchers at the Department of Energy's Oak Ridge National Laboratory (ORNL) have done tremendous job by succeeding in producing 50 grams of plutonium-238. With the achievement of this milestone, ORNL has restored a U.S. capability dormant for nearly 30 years and have demonstrated the nation’s ability to provide power for NASA and other deep space missions. The success of Wham and a team of engineers and technicians at ORNL came two years after NASA started funding the DOE Office of Nuclear Energy through a roughly $15 million per year effort to revive the department's capability to make plutonium-238.

The new sample of plutonium-238 could have significant implications in systems that power spacecraft instruments. The oxide powder form of the plutonium-238 used to manufacture heat sources for power systems, represents the first end-to-end demonstration of a plutonium-238 production capability in the United States since the Savannah River Plant in South Carolina ceased production of the material in the late 1980s.

Researchers said that there is need to analyze the sample for chemical purity and plutonium-238 content. They added that there is need to verify production efficiency models and determine whether adjustments need to be made before scaling up the process. Bob Wham, lead of the project for the lab's Nuclear Security and Isotope Technology Division, said that with the success of the automation and scaling process, the nation will have a long-range capability to produce radioisotope power systems such as those used by NASA for deep space exploration. Currently, there are only 35 kilograms, or about 77 pounds, of plutonium-238 set aside for NASA missions, and only about 50% this supply meets power specifications. This is only sufficient to power two to three proposed NASA missions through the middle of the 2020s.

The production of plutonium-238 starts at Idaho National Laboratory, which stores the existing inventory of neptunium-237 feedstock and ships it as needed to ORNL. Engineers mix the neptunium oxide with aluminum and press the mixture into high-density pellets. They use the High Flux Isotope Reactor, a DOE Office of Science User Facility at ORNL, to irradiate the pellets, creating neptunium-238, which quickly decays and becomes plutonium-238.

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