Explain the term "isotopic enrichment".

Isotopic enrichment refers to the process of increasing the concentration of a specific isotope within a sample. In nuclear applications, this is particularly relevant for isotopes used as fuel in reactors, such as uranium-235 in uranium. Natural uranium contains a small percentage of uranium-235, while most of it consists of uranium-238. Enriching the uranium increases the proportion of uranium-235, making it more suitable for use in nuclear reactors or for creating nuclear weapons. This enhancement in concentration enables better efficiency in fission reactions, leading to more energy production with less fuel.

The other answers do not accurately define isotopic enrichment. Decreasing the volume of nuclear material does not directly relate to the concentration of isotopes; rather, it refers to the physical amount of material present. Lowering radiation levels and cooling nuclear reactors involve safety and operational aspects of nuclear technology but do not pertain to the concentration of specific isotopes within a sample. Thus, the focus of isotopic enrichment is distinctly on adjusting the proportions of isotopes to optimize nuclear processes.