Patent ID: 8462909

Claim:
A method of measuring Doppler reactivity coefficient, comprising: measuring time-series data of neutron flux in which reactor power is increased by a prescribed amount by applying reactivity to a reactor core which is in sub-critical or achieves super critical, and obtaining time-series data of in-reactor average moderator temperature in which reactor power is increased by the prescribed amount by applying reactivity to the reactor core which is in sub-critical or achieves super critical, wherein in said measuring step, neutron flux during this period is measured as time-series data, and in said step of obtaining time-series data of in-reactor average moderator temperature, average moderator temperature in the reactor is obtained as time-series data; obtaining time-series data of reactivity in which the time-series data of reactivity is obtained from the measured time-series data of neutron flux, said time-series data of reactivity being calculated by applying an inverse kinetic method based on a one-point reactor kinetic equation; obtaining time-series data of reactor power by calculating the time-series data of reactor power based on said obtained time-series data of in-reactor average moderator temperature and the time-series data of neutron flux, such that the obtained time-series data of reactor power matches said two time-series data which are the time-series data of in-reactor average moderator temperature and the time-series data of neutron flux, obtaining time-series data of fuel temperature in which the time-series data of fuel temperature subjected to a prescribed averaging is obtained from the time-series data of reactor power obtained above and a reactor kinetic model; obtaining time-series data of reactivity feedback contribution component in which the time-series data of reactivity feedback contribution component is calculated from the time-series data of reactivity obtained above in said step of obtaining time-series data of reactivity, and the reactivity of constant reactor period; and obtaining Doppler reactivity coefficient, in which the Doppler reactivity coefficient is obtained from the obtained time-series data of in-reactor average moderator temperature, the obtained time-series data of fuel temperature subjected to said prescribed averaging, an isothermal temperature reactivity coefficient, and the obtained time-series data of reactivity feedback contribution component.