[en] Nuclide composition rates in radioactive waste arising from research institutes (Institutes-Waste), that are basic factor to select the important nuclides from the viewpoint of safety assessment of disposal, were evaluated, taking account of various waste arising conditions. The research facilities in JAERI Tokai establishment were categorized into three types, namely, research and testing reactors, facilities for nuclear fuel materials tests (PIE facilities), and radioisotope application laboratories, and nuclides composition rates applicable to Institutes-Waste of each facility type were evaluated using investigation of waste generation record, activation analysis, and radioactivity measurement data. As results, the nuclide composition rates of waste from the research and testing reactors depended on the nuclides in the coolant of the reactor; waste contaminated by irradiated fuel materials generated from the PIE facilities had a little variation range in the nuclide composition rates in spite of wide irradiation conditions; the nuclide composition rates of waste contaminated by activated materials were wide range depending on the irradiation conditions and kinds of materials; and 82 kinds of radioisotopes were in use by RI applications laboratories which gave the nuclide composition rates. Based on these results, the representative composition rates of nuclides in waste from each type of facilities and Institutes-Waste were determined, respectively. (author)