Abstract: This paper analyzes the feasibility of substituting the primary neutron source with the secondary neutron source (SNS) in pressurized water reactor under the background that the supply of the primary neutron source has risks. The neutron source intensity of SNS which experienced one fuel cycle irradiation in a working PWR was calculated. Based on the core parameters and loading sequence of the first cycle of a new CPR1000 reactor, the counting rates of neutron detectors inside and outside the reactor were calculated at various loading steps. The results show that the substitution of the primary neutron source with the irradiated SNS within 4 half-lives (about 240 d) in the CPR1000 reactor satisfies the requirements of neutron detector counting rates in related technical specifications, thus proving the feasibility of substituting the primary neutron source with SNS.