Irradiated Fuel, Refueling

Irradiated Fuel: A fuel assembly which has been involved in the fission process and is no longer effectively producing energy, but is still radioactive. Also known as "spent fuel". Refueling: The reactor is shutdown with reactor coolant temperature below 210° F and the reactor coolant system is open (reactor vessel head removed) to allow for irradiated fuel to be removed and new fuel assemblies to be added.