Toshiba's announcement that it will write down nearly ¥712.5 billion in losses involving its U.S. nuclear unit, Westinghouse, is seen as a major setback for the government's strategy of selling Japanese nuclear power technology abroad.

Over the past four years, Prime Minister Shinzo Abe, the Ministry of Economy, Trade, and Industry, and nuclear power players, such as Toshiba/Westinghouse, General Electric-Hitachi and Mitsubishi Heavy Industries, have promoted Japanese nuclear reactor technology worldwide.

Attempts to increase exports came even as concern within Japan grew over nuclear safety following a triple meltdown at the Fukushima No. 1 plant in the wake of the March 11, 2011 earthquake and tsunami. The efforts also came as questions were being raised about the total cost of nuclear power compared with other energy sources.