Tuumkütust

Tuumkütust refers to nuclear fuel, the material used in nuclear reactors to sustain a nuclear chain reaction. The most common type of tuumkütust is uranium, specifically the isotope uranium-235. Natural uranium contains a small percentage of uranium-235, and for most nuclear power reactors, this concentration is enriched to increase the proportion of fissionable uranium-235. Other materials, such as plutonium, can also be used as tuumkütust, often in mixed oxide (MOX) fuel.

The process begins with mining and milling uranium ore. The ore is then refined and processed into a form suitable for use in reactors, typically as ceramic pellets made of uranium dioxide. These pellets are then assembled into fuel rods, which are bundled together to form fuel assemblies. These assemblies are loaded into the core of a nuclear reactor.

When a neutron strikes a nucleus of uranium-235, it can cause the nucleus to split, or fission. This fission releases a significant amount of energy, in the form of heat, and also releases more neutrons. These neutrons can then go on to cause further fissions, creating a self-sustaining chain reaction. The heat generated by this reaction is used to produce steam, which drives turbines to generate electricity.

After a period of use, the tuumkütust becomes spent and is removed from the reactor. Spent tuumkütust is highly radioactive and requires careful handling and storage. It can be reprocessed to recover usable fissile material or stored in specialized facilities for long-term disposal. The management of spent tuumkütust is a significant aspect of the nuclear fuel cycle.