In the reprocessing of spent nuclear fuel, what is the initial step involved?

The initial step in the reprocessing of spent nuclear fuel involves shearing of fuel pins. This process is essential because it begins the separation of the various components within the spent nuclear fuel after it has been removed from the reactor.

When spent fuel is first discharged, it consists of a mix of fission products, actinides, and other materials that need to be separated for further processing. Shearing involves cutting the fuel assemblies into smaller pieces, which facilitates access to the fuel and allows subsequent chemical processes to effectively isolate valuable isotopes, such as uranium and plutonium, from waste products.

This step is crucial for the successful implementation of reprocessing and recycling of nuclear fuel, as it sets the foundation for later stages where the actual chemical extraction and separation take place. The other choices do not represent an initial reprocessing step, as neutralizing the waste stream, burning the spent fuel, and cooling the fuel rods are either part of subsequent waste treatment processes or safety measures not directly involved in the initial reprocessing phase.