Patent ID: 7970094

Claim:
An operation method of a nuclear power plant comprising the steps of: augmenting a second reactor thermal power output in a second operation cycle of a reactor larger than a first reactor thermal power output in a first operation cycle before the second operation cycle; and making a temperature rise amount at a high pressure feedwater heater in said second operation cycle smaller than a temperature rise amount at said high pressure feedwater heater in said first operation cycle, and making an enthalpy difference of a coolant between an inlet and outlet of said reactor in said second operation cycle larger than an enthalpy difference of said first operation cycle, wherein said nuclear power plant comprises: the reactor; a steam loop comprising a high pressure turbine and low pressure turbine where steam generated by the reactor is supplied; a condenser for condensing steam discharged from a low pressure turbine; a low pressure feedwater heater placed at a more downstream side than the condenser and at a more upstream side than a main feedwater pump, and a high pressure feedwater heater placed at a more downstream side than said main feedwater pump and at a more upstream side than said reactor; and a feedwater loop for leading feedwater discharged from the high pressure feedwater heater to said reactor.