[en] The radionuclides containing in primary cooling system in the 3MW TRIGA Mark-II research reactor (pool type) have been measured using a high resolution HPGe detector in conjunction with a 4096 channel analyzer. A total of 10 radionuclides (such as Na-24, Mg-27, Ar-41, Cr-51, Mn-54, Mn-56, Cu-64, Co-60, Zn-65 and Ag-110m) have been found in gamma ray spectra of primary cooling water, ion exchange resins and filter cartridge as activation products. The radionuclides which were detected are either in the water as a result of corrosion of material in the pool or in water soluble compounds of elements from material in the pool. No fission product radionuclides could be detected in the primary cooling system during the course of this experiment. This study will be useful not only from the point of view of radioactive waste management and radiation protection but also for safe operation of the reactor. (author)