Method for eliminating welding stress of sealed chamber in nuclear reactor

The invention discloses a method for eliminating the welding stress of a sealed chamber in a nuclear reactor. The sealed chamber comprises a non-magnetic conductive tube and a magnetic tube, wherein the magnetic tube is a circular ring-shaped welding part formed by alternately welding magnetic conductive rods and non-magnetic conductive rods which have the same shape; the cross sections of the magnetic conductive rods and the non-magnetic conductive rods are trapezoidal; the non-magnetic conductive rods in the non-magnetic conductive tube and the magnetic tube are made of 1Cr18Ni10Ti; the magnetic conductive rods in the magnetic tube are made of 0Cr13; and a sealed chamber workblank formed by welding is placed in a heat treatment furnace together with tool equipment located at the core ofthe sealed chamber workblank for heat treatment. The heat treatment process comprises the following steps of: firstly heating up to 300-500 DEG C, carrying out heat preservation for 0.5-1h, carrying out temperature equalizati