In-containment spent fuel storage to limit spent fuel pool water makeup

A method of refueling a nuclear team supply system having a nuclear reactor primary coolant loop enclosed, within a hermetically sealed containment wherein the containment comprises a nuclear reactor vessel for supporting and housing a plurality of nuclear fuel assemblies within a core, the nuclear reactor vessel being supported within the containment as part of the nuclear reactor primary coolant loop;

• a refueling cavity extending above the nuclear reactor vessel within the containment;
• an in-containment refueling coolant storage tank supported within the containment outside the refueling cavity at an elevation above the core for, upon command, flooding at least a portion of the refueling cavity with a refueling coolant in furtherance of refueling the reactor vessel, the in-containment refueling coolant storage tank having a full level substantially at which a volume of the refueling coolant is maintained during normal reactor operation;
• and an irradiated nuclear fuel assembly storage tank supported within the containment below a portion of the refueling cavity, the irradiated nuclear fuel assembly storage tank is configured with fuel assembly storage racks for storing irradiated nuclear fuel within the containment outside the core when the reactor vessel is in operation and the refueling cavity is drained, and the irradiated nuclear fuel assembly storage tank is configured to selectively place a nuclear fuel assembly storage tank coolant conduit, connected to the irradiated nuclear fuel assembly storage tank, in fluid communication with the in-containment refueling coolant storage tank or the refueling cavity;
• the method comprising:
• flooding the refueling cavity with the coolant from the refueling coolant storage tank;
• removing a head from the reactor vessel;
• opening a lid on the irradiated nuclear fuel assembly storage tank;
• removing at least some of the fuel assemblies from the core into the irradiated nuclear fuel assembly storage tank;
• closing the lid on the irradiated fuel assembly storage tank;
• loading a number of new fuel assemblies into the core;
• closing the head on the reactor vessel;
• draining the refueling cavity into the in-containment refueling coolant storage tank;
• and
• starting up the reactor with the at least some of the fuel assemblies removed from the core stored in the irradiated nuclear fuel assembly storage tank.