Perpetual Atomics, QSA Global produce Am fuel for nuclear space power

U.K.-based Perpetual Atomics and U.S.-based QSA Global claim to have achieved a major step forward in processing americium dioxide to fuel radioisotope power systems used in space missions. Using an industrially scalable process, the companies said they have turned americium into stable, large-scale ceramic pellets that can be directly integrated into sealed sources for radioisotope power systems, including radioisotope heater units (RHUs) and radioisotope thermoelectric generators (RTGs).

Historically, plutonium-238 has been the fuel of choice for space-based RHUs and RTGs. Am-241, however, has become an attractive alternative to Pu-238, particularly in Europe, which does not have a large inventory of available plutonium. In addition, Am-241 has a half-life of around 430 years, compared with the 90-year half-life of Pu-238, making it more suitable for long-duration missions.

The process: Using a new process not previously applied to americium, Perpetual Atomics and QSA Global said they have produced a ceramic americium pellet in the dimensions required for 3-Wt RHUs.

According to the companies, the process is scalable and amenable to industrialization, producing high-density pellets with high volumetric power density-critical to maximizing specific power in radioisotope power systems.

The new approach is rapid, minimizes pellet volume and waste, and maximizes throughput, enabling the production of larger-scale pellets tailored to the needs of future power systems, the companies added.

The collaboration: Perpetual Atomics, which was spun out of the University of Leicester and is based at the university's Space Park Leicester, announced in January 2025 that it signed a collaboration agreement with QSA Global to process americium into sealed sources for use in radioisotope power systems. QSA Global designs and produces commercial radioisotope sealed sources for industrial use.

Quotables: Joe Lapinskas, director of innovation and marketing at QSA Global, said, "In just one year of working together, Perpetual Atomics and QSA Global have gone from concept to manufacturable fuel pellets. By combining Perpetual Atomics' space nuclear power expertise with QSA Global's decades of sealed source design, qualification, and high-reliability manufacturing, we're turning a promising concept into real hardware ready to power the next generation of demanding space missions."

"Developing the fuel form and a stable processing method was the primary challenge, and this was successfully addressed first with surrogates and then translated to americium in collaboration with the QSA team in record time," said Ramy Mesalam, chief technical officer of Perpetual Atomics.

Matthew Cook, head of space exploration at the U.K. Space Agency, added, "Radioisotope power systems will be essential for future deep space missions and exploring extreme environments like the lunar south pole. By developing scalable americium fuel pelleting processes here in the U.K., we're ensuring British expertise remains at the forefront of this critical technology."