PUREXprosessissa

PUREXprosessissa, or the Plutonium Uranium Redox Extraction process, is a widely used industrial-scale process for the reprocessing of spent nuclear fuel. Its primary purpose is to separate uranium and plutonium from fission products and other actinides present in the fuel. The process was developed in the United States in the 1940s and has since been adopted by many countries with civilian nuclear power programs.

The PUREX process utilizes a solvent extraction method, typically employing tributyl phosphate (TBP) dissolved in a hydrocarbon solvent, like odorless kerosene. The spent nuclear fuel, usually in the form of oxide pellets, is first dissolved in nitric acid. This acidic solution then undergoes a series of extraction and scrubbing steps. In the main extraction phase, uranium and plutonium are selectively transferred from the aqueous nitric acid phase into the organic TBP phase, while most of the highly radioactive fission products remain in the aqueous phase.

Subsequent steps involve the separation of uranium from plutonium. This is achieved by altering the oxidation states of the elements. Plutonium can be reduced to a more water-soluble oxidation state, allowing it to be transferred back into an aqueous phase, effectively separating it from the uranium which remains in the organic phase. The recovered uranium and plutonium can then be further purified and are often destined for reuse as fuel in nuclear reactors or for other nuclear applications. The highly radioactive waste streams generated by the PUREX process require careful management and long-term storage.