31-03-2025
JAEA developing space probe battery fueled by radioactive waste
The Japan Atomic Energy Agency said that it has begun developing a small nuclear battery that converts the decay heat of americium — a radioactive waste — into electricity for use as a power source in space probes.
According to an announcement by the government-linked organization on Friday, the battery is expected to be used in probes that operate in places where solar power generation is not possible, such as asteroids and planets far from the sun, as well as the dark side of the moon.
The project was commissioned by the Japan Aerospace Exploration Agency (JAXA). The JAEA aims to complete a prototype by early 2029 in partnership with organizations including the government-affiliated National Institute of Advanced Industrial Science and Technology (AIST).
The United States has been using nuclear batteries employing plutonium since the 1960s, installing them on the Voyager interstellar probes and other machines.
Plutonium produces a high level of decay heat, or heat released as a result of radioactive decay, making it optimal for power generation. But Japan has strict legal restrictions on the handling and transportation of the element.
The JAEA therefore chose to make effective use of americium despite its low level of decay heat.
"If they are put into practical use, americium batteries can be used almost permanently as a power source for space probes' communication devices and sensors," said Masahide Takano, senior researcher at the JAEA's NXR Development Center.
According to Takano, sufficient amounts of americium can be secured by separating the element from powder materials of uranium-plutonium mixed oxide, or MOX, fuel possessed by the JAEA.
The agency has already developed a technology to bake americium into pellets with additives and enclose it in metal pins so that it does not scatter even if there is an explosion when a probe is launched by a rocket.
The JAEA has also succeeded in an experiment to make light-emitting diode lights glow by generating electricity with the decay heat of americium using semiconductors.
