[en] The TRIGA Mark II reactor is the main research facility in the Reactor Physics and Operation Division and in the Nuclear Chemistry Division of the J. Stefan Institute. The Nuclear Chemistry Section uses the reactor mainly in activation analysis of trace elements; projects include standardization of reference materials, the distribution and fate of heavy metals in the environment, trace elements in human milk, and biochemical and biomedical studies of trace elements. Among many different research projects carried out in the Reactor Physics and Operation Division, the following ones will be described: neutron scattering investigation of phase transitions in molecular crystals and investigation of the dynamics, as well as the position, of water molecules in biological samples of LiDNA and NaDNA, reactor dosimetry studies, measurements of neutron capture gamma transitions, the application of neutron induced and spontaneous alpha radiography to the determination of boron microdistribution in metals, determination of uranium distribution in uranium ores, uranium ore exploration surveys, and the production of ¹⁸F for medical applications. (author)