Understanding chemistry of nuclear materials and radioactive elements is necessary for a wide range of nuclear technology. For example, during treatment, storage, and disposal of radioactive wastes, chemical properties of the waste form, potential chemical change of the waste, and the stability of the radioactive elements must be understood prior to actual operation. Event today, however, it is often difficult to evaluate the chemistry of radioactive elements and the reactions by the ionizing radiation with a reasonable certainty. In addition, there is continuous need for improving throughput of analysis method for radioactive elements. We are working on these subjects, aiming to develop core technologies for understanding chemical behavior of radioactive elements. Our research scope covers radiation chemistry, spectroscopy, and analytical chemistry in the field of nuclear engineering.