plutonium-238

chemical isotope

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July 16, 2026

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Plutonium-238 is a radioactive isotope of plutonium, a chemical element with atomic number 94. It was first detected in 1941 by American chemists. Plutonium-238 is an alpha-emitting isotope that produces a negligible amount of gamma rays.1

Its primary application is in radioisotope thermoelectric generators (RTGs), which convert the heat from its radioactive decay into electrical power for spacecraft, such as the Curiosity rover. One gram of plutonium-238 generates approximately 0.5 watt of thermal power. This isotope has a half-life of 87.7 years. While plutonium-239 is used in nuclear reactors and weapons, plutonium-238's utility lies in its heat-generating properties for long-lasting power sources.123

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plutonium
…detected (1941) as the isotope plutonium-238 by American chemists Glenn T. Seaborg, Joseph W. Kennedy, and Arthur C. Wahl, who produced it by deuteron bombardment of uranium-238 in the 152-cm (60-inch) cyclotron at Berkeley, California. The element was named after the then planet Pluto. Traces of plutonium have subsequently been…
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…detected (1941) as the isotope plutonium-238 by American chemists Glenn T. Seaborg, Joseph W. Kennedy, and Arthur C. Wahl, who produced it by deuteron bombardment of uranium-238 in the 152-cm (60-inch) cyclotron at Berkeley, California. The element was named after the then planet Pluto. Traces of plutonium have subsequently been…
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transuranium element
Practical applications of transuranium isotopes
Three other transuranium isotopes—plutonium-238, americium-241, and californium-252—have demonstrated substantial practical applications. One gram of plutonium-238 produces approximately 0.57 watt of thermal power, primarily from alpha-particle decay, and this property has been used in space exploration to provide energy for small thermoelectric-power units.
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Three other transuranium isotopes—plutonium-238, americium-241, and californium-252—have demonstrated substantial practical applications. One gram of plutonium-238 produces approximately 0.57 watt of thermal power, primarily from alpha-particle decay, and this property has been used in space exploration to provide energy for small thermoelectric-power units.
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