For safeguards purposes, a set of phases over the lifetime of a nuclear facility, starting with the decision to construct, or authorize the construction of, the facility and ending when the IAEA and the State agree that the facility is decommissioned. The following comprise the facility life cycle phases: pre-construction, construction, commissioning, operating, maintenance or modification, shut down, closed down and decommissioned. It is possible for parts of a facility to be in different life cycle phases.