Preliminary investigation of the shutdown radioactivity for EAST based on gamma ray spectrometry

•The HPGe spectrometer system was placed inside the vacuum vessel to measure the characteristic γ-rays emission from radionuclides after EAST shutdown.•The identification and pathway analysis of radionuclides were discussed based on structural materials and radiation sources of EAST.•Activity of radionuclides and time evolution of dose rate, preliminary activation results, were discussed.