The Fukushima nuclear disaster is a special case: a major twin natural disaster(earthquake and tsunami) incited a large-scale technological disaster, which resulted in a serious nuclear accident. Because the various costs are so tremendous, this triple disaster has had a pervasive impact on all aspects of life in Japan. This article describes nuclear energy policy transformation in the aftermath of the Fukushim a disaster. The study draws on theoretical propositions of governance and disaster risk governance, and demonstrates that a vested interest perspective is important to understanding the results of Japan’s energy policy before Fukushima. Safety, democracy, and openness were the fundamental principles of Japan’s nuclear energy policy when the country decided to diversify its energy sources in the 1950 s. But these basic premises were undermined by the vested interests that controlled policy administration and implementation as the nuclear energy industry developed. Analysis of Japan’s recent nuclear energy policy transformation covers such dimensions as policy targets, policy issues such as safety, the fuel cycle, waste disposal, administrative structure, public awareness, and national and local policy considerations. The study identifies process deficiencies in Japan’s post-Fukushima nuclear energy policy transformation and evaluates possible ways to eliminate defects through administrative reorganization and independent safety oversight.