Reactor power distribution test method and system based on in-reactor self-powered detector

The invention discloses a reactor power distribution test method and a reactor power distribution test system based on an in-reactor self-powered detector, and relates to the field of nuclear reactor physical tests. Establishing a coupling coefficient of each segment in each fuel assembly by using a coupling coefficient method; acquiring fixed and discrete actually measured current data acquired by the in-reactor self-powered detector, and expanding by adopting a high-order fitting method to obtain continuous power distribution information; according to the coupling coefficient and the continuous power distribution information, on-line power distribution expansion software is adopted for expansion to obtain whole-pile actual measurement power distribution; and comparing the fine power distribution of the reactor core in the transient state with the actually measured power distribution of the whole reactor to obtain a power distribution deviation test result. According to the method, on the basis of transient