No form of energy is risk-free and Japan has a security of supply problem that means it is also at risk from not restarting commercial reactors and using nuclear power, a webinar organised by the American Nuclear Society was told.

Asked if the Fukushima-Daiichi accident proved that nuclear energy is “too risky and cannot be controlled”, Dale Klein, who was chairman of the US Nuclear Regulatory Commission from 2006 to 2009, said Japan imports most of its energy and this puts it at risk.

“There is a risk of not having nuclear energy in Japan,” said Mr Klein, who also chaired an international group that monitored Tokyo Electric Power Company’s progress following the March 2011 Fukushima-Daiichi accident. “It is a risk for the government, for society and for the military.”