Technology
The Production of Plutonium 239 in Breeder Reactors
The Production of Plutonium 239 in Breeder Reactors
Introduction to Plutonium 239 and its Relatives
Plutonium 239 (Pu-239) plays a significant role in the field of nuclear energy and serves as a vital component in the nuclear fuel cycle. This article provides a comprehensive overview of the process by which Pu-239 is produced, primarily in breeder reactors. We will discuss the role of uranium-238 (U-238) and the subsequent steps involved in its conversion to plutonium.Obtaining Fertile U-238 Material
The first step in the production of plutonium-239 is the acquisition of a fertile material, specifically uranium-238 (U-238). This isotope is characterized by its ability to absorb neutrons, which sets the stage for the transmutation process.Conversion in the Heavy Water Reactor
U-238 is placed within a heavy water reactor, where it is bombarded with neutrons. The process involves the transmutation of U-238 to various isotopes, eventually leading to the formation of plutonium-239. As mentioned in the Wikipedia entry, a significant amount of Pu-239 is produced in this manner.Step-by-Step Process in a Breeder Reactor
A breeder reactor is designed to produce more fissile material (such as plutonium-239) than it consumes. This occurs through a series of nuclear reactions:
The process begins with the absorption of a neutron by a U-238 nucleus, initiating the formation of U-239. U-239 is a short-lived isotope that undergoes beta decay into neptunium-239 (Np-239). Beta decay involves the emission of an electron, altering the neutron-to-proton ratio in the nucleus. Np-239 then undergoes beta decay into plutonium-239 (Pu-239). This results in a change from 93 protons to 94 protons, transforming the element from neptunium to plutonium.These beta-decay processes occur with half-lives of approximately 23 minutes and 2 days, respectively. The end result is the production of plutonium-239, which is highly valuable for nuclear applications, including the production of nuclear fuel.
Breeder Reactors vs. Light Water Reactors
It's important to note that this process of plutonium production is not exclusive to breeder reactors. Traditional light water reactors, such as those in the US nuclear industry, also have a significant amount of U-238 in their fuel rods. While these reactors primarily use enriched uranium-235 (U-235) as their fuel, a considerable portion of the power generated during their operational cycles comes from the fission of plutonium-239 that is produced during normal operation.
Conclusion
In summary, the production of plutonium-239 in breeder reactors is a complex yet fascinating process involving the absorption of neutrons by uranium-238 and subsequent beta-decay events. This material plays a crucial role in the nuclear fuel cycle, contributing to both energy production and potential military applications.