A top official at Japan's nuclear-safety regulatory agency sees no slowing in the country's campaign to expand atomic power, despite the battle to contain the world's worst nuclear crisis in 25 years, saying in an interview that the alternative is "blackouts."

"There aren't that many easy alternatives available for us," said Hidehiko Nishiyama, a former trade negotiator tapped to help deal with the Fukushima nuclear crisis, on Wednesday. "Japan couldn't go forward without nuclear power in order to meet its demand for energy today," he said. About 30% of Japan's electricity output comes from nuclear, and the government has set the goal of increasing that to 40% by 2020.