The utility model discloses a reaming device for nuclear power plant, including the base that is used for fixed thermocouple pipe carrier, the perpendicular connection reference column on the base, parallel the reference column setting is in reference column one side and extend to the brill sword of base and at least one are right bore the setting element that the sword advances line location, thesetting element is followed it fixes to the distribution to bore the arbor on the base, and the setting element is equipped with the confession bore the rotatable locating hole that passes of sword.The utility model discloses a reaming device for nuclear power plant for reaming and groove preparation work are carried out in thermocouple pipe position in thermocouple pipe cutting back, and the processed counter bore satisfies the designing requirement, and the quality is handled to the guarantee defect, and furthest realizes the mechanization and the automation of working process, and the reduction personnel pile the operating time in hole at the reactor, control staff's radiation dose, have ensured staff's safety.