Method of refueling a nuclear reactor

A method of refueling a nuclear reactor comprising a reactor vessel having an open upper end with a flange, the reactor vessel housing a core including a plurality of fuel assemblies and an upper internals structure supported above the core, and a head with a mating flange for sealing the open upper end of the reactor vessel;

• the method comprising the steps of:
• removing the reactor vessel head;
• placing the reactor vessel head in a first storage location outside of a path above the reactor vessel;
• lifting the upper internals structure out of the reactor vessel to a second storage location outside of the path above the reactor vessel;
• installing a cylindrical tank having an open lower end and an open upper end, on the reactor vessel flange;
• sealing the lower end of the cylindrical tank to the reactor vessel and a penetration on a side of the cylindrical tank to a refueling canal that is connected to a spent fuel pool;
• raising a level of reactor coolant within the reactor vessel to at least partially fill the cylindrical tank substantially to a level equal to a level of a coolant within the spent fuel pool;
• opening the refueling canal;
• and
• employing a refueling machine at least in part supported above the cylindrical tank, to transfer a number of the fuel assemblies within the core, through the penetration and the refueling canal to a storage location in the spent fuel pool.