Calling it “a seminal event in the history of nuclear power,” the chairman of the U.S. Nuclear Regulatory Commission told the AAAS Forum on Science and Technology Policy that the tsunami-triggered accident at the Fukushima Daiichi facility in Japan is likely to provide nuclear safety lessons for regulators in this country as well as Japan.

A world without nuclear weapons, widely considered a desirable if challenging goal over the long term, could pose new uncertainties and risks, experts from the United States and Japan said during a day-long symposium at AAAS.

The legal framework does not yet exist that would allow the pursuit of a nuclear-free world, they said. Nor has there been enough clear-headed analysis of the potentially de-stabilizing impact of a world with zero nuclear weapons where terrorists or rogue states might not play by the rules.