Ydinaineksen

Ydinaineksen is a Finnish term that translates to "nuclear material" or "fissile material" in English. It refers to materials that can sustain a nuclear chain reaction. These materials are primarily isotopes of certain heavy elements, most notably uranium and plutonium.

The most common fissile isotope is Uranium-235 (U-235). Natural uranium consists of about 99.3% Uranium-238 (U-238) and only about 0.7% U-235. For most nuclear applications, such as in nuclear reactors or weapons, the concentration of U-235 needs to be increased through a process called enrichment. Plutonium-239 (Pu-239) is another significant fissile material, which is not found in nature but is produced in nuclear reactors from U-238.

The ability of ydinaineksen to undergo fission, releasing a significant amount of energy and neutrons, is the basis for nuclear power generation and nuclear weapons. Neutrons released during fission can strike other fissile nuclei, causing them to fission as well, thus creating a self-sustaining chain reaction. Controlling this chain reaction is crucial for safe and efficient operation of nuclear reactors. The handling and storage of ydinaineksen are subject to strict international regulations due to its potential for misuse and the inherent radiological hazards.