Plutonium 238
Plutonium-238: An Overview
Plutonium-238 is a radioactive isotope of plutonium with significant applications in energy production and technology. Its discovery dates back to December 1940, when it was synthesized by Glenn Seaborg and his associates through a process involving the bombardment of uranium-238 with deuterons. This reaction produces neptunium-238, which undergoes beta decay to form plutonium-238.
Properties and Characteristics
Plutonium-238 is a potent alpha emitter, releasing alpha particles that are easily blocked, making it ideal for use in enclosed systems where shielding from radiation is paramount. The isotope possesses a half-life of 87.74 years and a density of approximately 19.8 g/cc at room temperature. It emits about 0.57 watts of thermal energy per gram, a critical trait for its applications in energy generation.
Applications in Technology
One of the primary uses of plutonium-238 is in radioisotope thermoelectric generators (RTGs). These devices convert the heat generated by radioactive decay into electricity, a function that has been invaluable in powering spacecraft and other remote systems. The United States first deployed an RTG using plutonium-238 in 1961 aboard the Navy Transit 4A spacecraft. The isotope's ability to provide consistent energy over long periods makes it ideal for missions where solar power is impractical.
Another significant application of plutonium-238 is in radioisotope heater units. These units provide necessary heat to spacecraft components, ensuring their proper functionality in the cold vacuum of space.
Production and Synthesis
The synthesis of plutonium-238 involves bombarding uranium-238 with deuterons to produce neptunium-238, which then decays into plutonium-238. This process underscores the interconnectedness of various elements in the actinide series, including americium-241 and plutonium-239, which also play roles in nuclear technology and energy production.
Plutonium-238 is produced at facilities like the Savannah River Site, which have been pivotal in supplying this isotope for various applications, including historical missions like Apollo and Voyager.
Safety and Handling
Despite its usefulness, handling plutonium-238 requires stringent safety measures due to its radioactivity. Its ability to emit alpha particles necessitates proper shielding to prevent contamination and exposure, underscoring the need for carefully controlled environments.