This paper analyzes the impacts of the March 11, 2011, earthquake and tsunami at the Fukushima nuclear power plant in Japan, which were amplified by a failure of coordination across the plant, corporate, industrial, and regulatory levels, resulting in a nuclear catastrophe comparable in cost to Chernobyl. It derives generic lessons for industrial structure and regulatory frame for the electric power industry by identifying the two shortcomings of a horizontal coordination mechanism: instability under large shocks and the lack of “defense in depth.” The suggested policy response is to harness the power of “open-interface-rule-based modularity” by creating an independent nuclear safety commission and an independent system operator owning the transmission grid module in Japan. We propose a transitory price mechanism that can restrain price volatility while providing investment incentives.