Nuclear Fuel Cycle
Nuclear Fuel Cycle is the name given to the set of industrial processes that turn uranium ore into fuel that generates energy in the nuclear reactors.
The following processes or steps making up the fuel cycle are:
- Mining and processing – after removal from the earth, the uranium-bearing rock is crushed ground; then, it is subjected to a chemical process to separate the uranium from other materials associated with it in nature. The result from this first stage of the fuel cycle is uranium concentrate, or yellowcake. This step is currently performed at the Uranium Concentrate Unit in Caetité / BA.
- Conversion – the uranium concentrate is dissolved and purified, and then converted to gas, uranium hexafluoride (UF6). Only in the gaseous form, uranium can be moved to the enrichment step, the next stage of the nuclear fuel cycle. The conversion step is not performed in Brazil.
- Enrichment – it is the increase in uranium concentration that makes it possible to use it as fuel. This concentration goes from 0.7%, as found in nature, up to 4% (enough for energy generation). Brazil uses the ultracentrifugation technology to enrich uranium at INB’s Nuclear Fuel Factory in Resende/RJ.
- UF6 to UO2 Conversion – the enriched gas is converted into uranium dioxide powder (UO2). This step is performed at INB’s Nuclear Fuel Factory in Resende/RJ.
- Pellet fabrication – with enriched uranium in the form of powder, pellets are fabricated with about one centimeter in diameter. This step is performed at INB’s Nuclear Fuel Factory in Resende/RJ.
- • Nuclear fuel manufacture – small enriched uranium pellets are placed inside rods of a special alloy steel - Zircaloy. Then the rods are arranged in bundles to form a firm structure of up to 5 meters - the nuclear fuel. This step is performed at INB’s Nuclear Fuel Factory in Resende/RJ.
- Power generation – it is the fission of uranium atoms contained in the nuclear fuel inside the reactor core that generates heat, heating up the water, and turning it into steam that makes turbines move, generating power. This stage of the nuclear fuel cycle is performed in nuclear power plants at Angra dos Reis / RJ.