The risk of climate change has been increasing because of the increase of CO2 emission from fossil fuel burning. We are therefore required the utilization of safety-enhanced NPPs, which is also the strategy of energy security in Japan. However, the Japanese people have concern about the disposal of long-lived radioactive waste produced in this strategy. The prototype reactor Monju is now recognized as the international research center for reduction of long-live radioactive waste. This presentation based on the lessons learned from accidents and maintenance in prototype reactor Phenix in France shows the information useful for the risk communication on prototype reactor Monju.