Sumiko is interested in exploring the history of nuclear weapons and nuclear power from radiation risk perspective: how radiation risk has been understood, framed and weighed against other risks; and how such risk perceptions, in turn, have influenced nuclear policies. Sumiko previously worked for Peace Boat, a Japan-based international NGO. With Peace Boat, she travelled to over 20 countries with the atomic-bomb survivors, testifying to the humanitarian consequences of nuclear weapons.