METHOD FOR OPERATING NUCLEAR REACTOR AND NUCLEAR POWER GENERATION PLANT

PROBLEM TO BE SOLVED: To provide a method for operating a nuclear reactor and a nuclear power generation plant, which can improve fuel economy even when the thermal output of a nuclear power generation plant is increased and the operation cycle is lengthened. SOLUTION: The method for operating a nuclear reactor includes the step of, when the flow of a coolant to be supplied to the core of the nuclear reactor being operated with its reactor power at the preset level in a single operation cycle of a nuclear power generation plant is increased at a late stage of the operation cycle, lowering the temperature of water to be supplied to the reactor. Such an operation method can improve fuel economy even when the thermal output of a nuclear power generation plant is increased and the operation cycle is lengthened. In particular, the operation method can prevent a rise in temperature of the coolant at the inlet of the core even if the core flow increases at a late stage of the operation cycle and can make the reactivity gain when increasing in core flow at a late stage of the operation cycle greater than that which would be obtained simply by increasing the core flow. COPYRIGHT: (C)2011,JPO&INPIT