The JRR-3 achieved the first criticality in 1962 as the first research reactor constructed with the homegrown technology and had been utilized by a lot of researchers from the drawn of nuclear research and industry. In 1990, the JRR-3 was modified for upgrade and resumed its operation as a high performance and multipurpose research reactor with thermal power of 20 MW. The JRR-3 has several utilization facilities for neutron beam experiments, irradiation tests for nuclear fuel and material, and production of RI and silicon semiconductor. Cold neutron (very low energy neutron) beams are available and utilized for clarification of life phenomena by analyzing structure of polymer molecules, for example.