The End of Solar Power: Japan Builds a New Nuclear Battery Capable of Lasting More Than 100 Years
The Japan Atomic Energy Agency (JAEA) has embarked on an innovative project to develop a small nuclear battery that converts the decay heat of americium—a radioactive waste—into electricity.
This battery is specifically designed for use as a power source in space probes that operate in locations where solar power generation is not possible. These locations include asteroids, distant planets far from the Sun, and the dark side of the Moon.
A Collaboration with JAXA and AIST
According to Japan Times, the project is being led by JAEA in collaboration with the Japan Aerospace Exploration Agency (JAXA). The JAEA is aiming to complete a prototype of the new battery system by early 2029. This ambitious project is also supported by the government-affiliated National Institute of Advanced Industrial Science and Technology (AIST). The cooperation between these organizations is expected to drive the development of this specialized power source for space exploration.
The Role of Americium
Americium, a radioactive element, is produced when plutonium in spent nuclear fuel naturally decays. In contrast to plutonium, which has been used in the United States since the 1960s for powering space probes, americium produces less decay heat.
However, it has certain advantages, particularly when it comes to legal constraints in Japan. Plutonium is subject to strict legal restrictions on its handling and transportation, which is why JAEA has turned to americium instead.
While americium’s decay heat is lower, it is still sufficient for use in long-duration space missions. According to Masahide Takano, a senior researcher at the JAEA’s NXR Development Center, americium batteries, if they reach practical use, could provide almost permanent power for space probes.
This would enable the power of communication devices and sensors on space probes for much longer periods, a critical requirement for missions to distant celestial bodies.
Securing Americium for the Battery
The JAEA has already devised a method for securing sufficient amounts of americium by separating the element from uranium-plutonium mixed oxide (MOX) fuel, which the agency has in its possession. This fuel is used in nuclear research and is a vital resource for the americium extraction process.
In order to safely handle americium, the JAEA has developed a technique to bake it into pellets mixed with additives and enclose it within metal pins. This process ensures that the americium remains contained, even if there is an explosion during the launch of a space probe, providing a critical safety measure during rocket launches.
Demonstration of the Technology
The JAEA has already successfully demonstrated the potential of americium by using it to power light-emitting diode (LED) lights. The agency generated electricity using americium’s decay heat and a semiconductor-based technology. This experiment marks a significant step forward in proving that americium can indeed be used for reliable, long-lasting power generation.
Development Timeline and Future Prospects
The JAEA is working diligently toward completing the prototype battery system by 2029. The new battery will be compact and lightweight, making it suitable for use in space probes. The goal is for the battery to withstand the extreme conditions of space, including the vacuum of space and the intense temperatures that can vary greatly depending on the proximity to the Sun.
The collaboration between JAEA, JAXA, and AIST aims to ensure that this new power source will be both durable and efficient, paving the way for extended space exploration missions in regions where solar power is not a viable option.