Takubo is the organizer of the website “Nuclear Information” (http://kakujoho.net/). He has served as international director of Gensuikin, lecturer at Hosei University (peace studies), and consultant to the Science and Security Program at Princeton University before assuming his current position. He is a member of the International Panel on Fissile Materials (IPFM). He is the author of Plutonium: Nuclear Dream Fuel Becomes Nightmare (with Frank von Hippel and Jungmin Kang, Green Wind Publishing, 2021).