Nuclear batteries, also known as radioisotope thermoelectric generators (RTGs) or atomic batteries, are compact energy sources that derive power from the decay of radioactive isotopes. Unlike nuclear reactors, which use chain reactions to produce energy, nuclear batteries rely on the steady emission of heat from radioactive decay to generate electricity, typically via thermoelectric or betavoltaic systems. These devices are particularly useful in environments where long-term, maintenance-free energy supply is crucial, such as in deep-space missions or remote terrestrial locations.
The core of a nuclear battery consists of a radioisotope—commonly plutonium-238, strontium-90, or promethium-147—which emits particles as it decays. In thermoelectric generators, this decay heats a thermocouple, which then converts the thermal energy into electricity using the Seebeck effect. Betavoltaic batteries, on the other hand, convert beta particles directly into electricity through semiconductor junctions, somewhat like a photovoltaic solar cell. While thermoelectric RTGs offer higher power outputs, betavoltaic cells can last for decades with extremely low degradation, making them ideal for implantable medical devices and sensor systems.
One of the primary advantages of nuclear batteries is their extraordinary longevity. Since radioactive isotopes decay at predictable rates, these batteries can provide a consistent power supply for years or even decades without refueling or recharging. For instance, NASA’s Voyager spacecraft, launched in the 1970s and still transmitting data today, are powered by RTGs. This makes nuclear batteries indispensable for space exploration, where solar energy becomes insufficient beyond Mars or in permanently shadowed regions of the Moon.
Safety and environmental concerns remain central to the discussion of nuclear battery deployment. The isotopes used are highly radioactive and must be securely contained to prevent contamination or exposure. In most modern RTG designs, isotopes are encased in robust ceramic and metal shells that can withstand extreme temperatures, impacts, and chemical corrosion. Regulatory bodies such as the U.S. Department of Energy and the International Atomic Energy Agency (IAEA) have strict guidelines for the handling, transport, and disposal of radioisotope materials to minimize risk.
Recent research aims to improve the efficiency and safety of nuclear batteries while reducing their size and cost. Advances in nanomaterials and thermoelectric compounds have shown promise in significantly enhancing energy conversion rates. Some companies and research institutions are also exploring the use of diamond-based betavoltaic cells, where carbon-14 harvested from nuclear waste is used to produce long-lasting microbatteries. These developments could revolutionize not only space technology but also wearable electronics, medical implants, and autonomous sensors.
Despite their niche application today, nuclear batteries exemplify a unique intersection of nuclear physics and electrical engineering. As technological needs evolve, especially in the face of climate change and the demand for energy autonomy, nuclear batteries may play a growing role in delivering clean, compact, and reliable power sources.
OJ Engineering Team
References:
NASA (2025) Radioisotope Power Systems., NASA Jet Propulsion Laboratory.
World Nuclear Association (2023). Radioisotope Thermoelectric Generators.
Lane, N. (2016). Power from decay: Betavoltaic nuclear batteries. Nature Nanotechnology, 11, 801–803.
INL (Idaho National Laboratory). (2021). Understanding RTGs.
Whetstone, Z. (2020). Diamond nuclear batteries could last thousands of years. IEEE Spectrum.
Image Reference:
Flaherty, N. (2024, January 14). Scalable nuclear battery uses diamond for 50 year life. eeNews Europe