America is undertaking a bold and transformative initiative to convert decades-old radioactive waste into a strategic energy asset, developing advanced power systems that could operate for decades in the most extreme environments on Earth, underwater, and in space. This ambitious endeavor is being driven by the U.S. Department of Defense’s Defense Advanced Research Projects Agency (DARPA) through its “Rads to Watts” program, and by private companies like Zeno Power, which are forging public-private partnerships with the Department of Energy (DOE) to give new life to Cold War-era nuclear byproducts .

At the heart of this innovation is the effort to recycle Strontium-90 (Sr-90), a radioactive isotope created as a waste product in nuclear fission reactors and from spent nuclear fuel, which has been in long-term storage for decades . Historically, over 100 radioisotope thermoelectric generators (RTGs) in the United States used Sr-90 as fuel, and the current push seeks to revive and significantly advance this technology for 21st-century applications . A central figure in this movement is Zeno Power, which, through a public-private partnership with the DOE, has secured access to a legacy Sr-90 source known as the BUP-500 that had been stored at Oak Ridge National Laboratory in Tennessee for nearly 40 years . This material, once considered a liability destined for disposal, was transferred to a commercial nuclear facility to be processed into fuel for new radioisotope power systems (RPS) . The overarching theme of this collaboration is to “Reduce, Recycle and Revitalize”: reducing a DOE liability, recycling nuclear material for beneficial re-use, and revitalizing Sr-90 RPS technology .

Concurrently, DARPA’s “Rads to Watts” program is pushing the technological frontier by funding a multi-organizational team to develop a new class of radiovoltaic devices that convert radioactive decay directly into electricity with significantly higher power density . Led by Morgan State University, this team includes defense giant Northrop Grumman, the Pacific Northwest National Laboratory (PNNL), and the nuclear recycling company Project Omega, among others . The program’s flagship project, named SYMPHONEE, is designed to harness energy from Sr-90 to create miniature nuclear power systems that can run for decades without refueling or maintenance . The goal is to achieve power densities exceeding 10 watts per kilogram, a significant improvement over traditional technologies, by combining ultra-thin semiconductor layers with high-energy beta-emitting isotopes . Northrop Grumman is applying its expertise in microelectronics and radiation effects, using AI-driven modeling to simulate and ensure these systems can survive the harsh conditions of space, contested battlefields, and underwater environments .

The potential applications for these long-lasting, maintenance-free power sources are transformative, particularly for national security and space exploration . They are being developed to provide persistent power for next-generation defense systems, including unmanned aerial vehicles (UAVs) that could remain aloft for years, underwater infrastructure, remote sensors, and single-person electronics where replacing batteries is costly or impossible . For NASA and the Department of Defense, these systems offer a new paradigm for operations from the seabed to the lunar surface, providing an alternative to the limited supply of plutonium-238 traditionally used for deep-space missions . Project Omega’s CEO, Stafford Sheehan, framed the strategic importance, stating that the program demonstrates “how recovered isotopes can power critical systems for years, without needing to manage the logistics around constant battery replacement” . The first commercial RPS systems from companies like Zeno Power are expected to reach the market as early as 2026, with a minimum viable prototype from the DARPA program anticipated in early 2027 . While challenges remain in energy conversion efficiency and long-term reliability, this initiative marks a paradigm shift, viewing not just a dangerous byproduct, but a strategic resource that can solve one of the most daunting logistical challenges for future defense and exploration missions: ensuring a reliable, long-term power supply .