Undocumented Uranium Exports in the Democratic Republic of the Congo

• Authors: Ryan A. Manzuk (Princeton University) and Sébastien Philippe (University of Wisconsin-Madison)
• Title: Uranium in cobalt-hydroxide exports from the Democratic Republic of the Congo
• Journal: Nature Communications

The Shinkolobwe mine, located in the southern region of the Democratic Republic of the Congo (DRC) and home to the uranium ore used in the Manhattan Project’s bomb, has been closed by presidential decree since 2004. In that time, the DRC has reported no uranium exports. However, the region remains an active mine site for other resources, including 70 percent of the world’s cobalt.

In new research published on July 30 in Nature Communications, Ryan Manzuk, a postdoctoral research associate in the Program on Science and Global Security at Princeton University, and Sébastien Philippe, an assistant professor of nuclear engineering and engineering physics at the University of Wisconsin — Madison, show that large quantities of unreported uranium are still leaving the DRC, having attached itself to the cobalt compounds being mined to create everyday items like cell phones and laptops.

Using geologic maps and models, chemical models, and import/export analyses, Manzuk and Philippe estimate that uranium has been shipped outside of official records for nearly 25 years.

“Uranium doesn’t remain confined to concentrated deposits like Shinkolobwe and actually is known to have spread across the region over the last few million years so that the minerals exploited to make stable lithium-ion batteries also carry elevated quantities of uranium,” Manzuk said. “The final piece of the puzzle comes in when you read reports put out by engineers and scientists working in these cobalt mines stating that uranium and cobalt have similar chemical behaviors in the refining process, and so nearly all the uranium that comes out of the ground when digging for cobalt minerals will remain in the final product shipped from the DRC. Refineries can implement explicit processes to remove uranium from cobalt, but discussions of these techniques have only happened in recent years and are not common.”

Manzuk and Philippe estimate that 2,000 to 5,000 metric tons of natural uranium were exported out of the DRC in cobalt-hydroxide shipments between 2000 and 2024, with the majority being exported to China.

“Less than 10 percent of this material appears to have been publicly declared to the International Atomic Energy Agency (IAEA), responsible for uranium accountancy and safeguards,” Manzuk said. “This quantity of uranium could be used to produce fissile material for roughly 600 to 1,500 nuclear weapons or fuel a standard light-water nuclear reactor for 10 to 25 years.”

The research also identified a loophole in international uranium accountancy.

“Even if mines in the DRC were systematically implementing uranium removal strategies to keep cobalt products within international shipping limits for radioactivity, enough uranium would be reaching China to make approximately 12 nuclear weapons per year,” Manzuk said. “Not declaring this amount of uranium to the IAEA is a violation of the Additional Protocol of China’s safeguards agreement. The sheer size of the DRC’s cobalt industry poses a uranium accountancy problem, regardless of uranium grades in ores or removal strategies.”

Beyond the global security risk of undocumented uranium exports, Manzuk and Phillipe also illustrate the widespread risks to the people and environments near these mines and beyond.

“We estimate 1,000 to 4,000 metric tons of uranium have been discarded in highly mobile forms at these mines during the same time period,” Manzuk said. “People are exposed to this uranium when working in the mines, and it poses an environmental health and safety risk to the surrounding communities. Prior research has shown that some populations of miners and communities near mines in the DRC show signs of uranium exposure that is beyond the recommended dosing even for workers in nuclear industries.”