Abstract: This paper briefly introduces the replacement scheme of 16 flange bolts in No.1 sealed chamber of CPR1000 nuclear power plant reactor coolant pump（RCP）, which should be replaced by spare parts during the installation and operation of the construction for some reason. The innovation scheme of 4×4 replacement is used for the disassembly and inspection of 16 flange bolts, instead of the traditional whole replacement of 16 bolts. The innovation scheme reduces the work load in narrow space, optimizes the time schedule and avoids risks.