Tech Insights

Repurposing Radioactive Waste for Clean Energy Innovation

February 28, 2024 by Claire Turvill

An agreement between Oak Ridge National Laboratory, the Department of Energy, and Zeno Power promotes decaying radioisotopes to generate clean energy. 

In an agreement with the Department of Energy (DOE), Zeno Power will recycle Oak Ridge National Laboratory’s strontium-90 (Sr-90) waste from its 500 W Byproduct Utilization Program (BUP-500) electric radioisotope thermoelectric electric generator (RTG).

Zeno will use the radioactive waste to power a full-scale radioisotope power system (RPS), generating renewable energy for space missions and in remote locations on Earth.

Oak Ridge National Laboratory (ONRL) has stored the strontium-90 at its Tennessee facility for 40 years.


Transport of BUP-500.

Transport of BUP-500. Image used courtesy of Zeno Power 


Strontium-90 for Off-Grid Power

Zeno Power’s RPSes create renewable energy by converting heat from the decay of radioisotopes.

RPSes have been reliable off-grid power sources for space missions and other applications for decades. While plutonium-238 has been a staple for space applications, Zeno is currently developing a system utilizing Sr-90 as an alternative heat source.

Sr-90 is typically a byproduct of nuclear fission reactors, making it more abundant and cost-effective than plutonium. However, strontium-based RPSes are often bulky, limiting their utility to specific terrestrial applications. Zeno claims its technology can enhance the power density of strontium heat sources, expanding the range of potential applications both in space and on Earth.

A collaborative agreement between Zeno Power, ORNL, and the DOE permits Zeno to recover Sr-90 for its first full-scale RPS—also referred to as RTGs—from the BUP-500 RTG. 


Future of Strontium-90 Power Generation

ORNL is currently underway with a clean-up initiative and demolition of the facility where the BUP-500 was stored. By handing off the BUP-500 to the Zeno team, ORNL and the DOE are facilitating a cost-effective and safe recycling of a nuclear source. 


Testing the RPS.

Testing the RPS. Image used courtesy of Zeno Power


Zeno’s Sr-90 RPS was successfully tested last October in Richland, Washington, at the Pacific Northwest National Laboratory. 

The Zeno team is hopeful they will have commercialized RPSes ready by 2026. They have announced a partnership with Westinghouse Electric Company to handle the processing of radioactive material for its commercial RPS. Zeno also partners with NASA, the Department of Defense, Blue Origin, and Intuitive Machines to support oceanic and space exploration.