Final answer:
Equipment decommissioning involves safely removing equipment from service and reducing radioactivity, as seen in the example of a nuclear reactor.
Step-by-step explanation:
The formal procedure for taking equipment out of service and ensuring it cannot be operated is known as equipment decommissioning. An example of this is when a nuclear reactor stops operating and needs to be safely removed from service. This involves removing the reactor and all equipment that has become radioactive, reducing radioactivity to a safe level, and cleaning up any radioactively contaminated systems and structures.