Avalanche Energy, a Seattle-based fusion startup, has been awarded a $5.24 million contract from DARPA under its "Rads to Watts" program to develop compact alpha-voltaic nuclear batteries — devices that convert the energy from radioactive decay directly into electricity. [1]

The technology is not fusion. It is, in a sense, fusion's enabler. Alpha-voltaic batteries use new materials to capture alpha particles emitted by radioactive isotopes and convert them into usable current. They are small, long-lasting, and require no moving parts. DARPA's interest is military: a battery that lasts years without recharging could power remote sensors, satellites, or autonomous systems in environments where solar and chemical batteries fail. [1]

But the broader significance is what these batteries mean for fusion research itself. Fusion reactors produce intense radiation as a byproduct. If that radiation can be harvested efficiently — turned from waste into power — it changes the economics of every fusion design currently under development. Avalanche is working on both: a compact fusion device called the "Orbitron" and now the battery technology that could make its byproducts useful. [1]

On X, fusion enthusiasts treated the DARPA contract as a milestone, arguing that radiovoltaics are the unglamorous but essential technology that could close the gap between experimental fusion and practical power generation. [2] The broader energy press has been quieter. Nuclear batteries lack the drama of a fusion breakthrough. They are, however, the kind of incremental advance that actually moves timelines.

-- KENJI NAKAMURA, Tokyo