The chairman of the nuclear safety regulator on Wednesday dismissed calls for greater debate about the threat volcanoes pose to atomic power plants.
Some volcanologists have called for greater discussion of the risk of unforeseen eruptions before reactor restarts take place.
All of Japan's reactors remain offline. But the southwestern Sendai plant, which is located in a region with numerous active volcanoes, is tentatively cleared for restart after the Nuclear Regulation Authority said in September it had cleared new safety requirements.
NRA Chairman Shunichi Tanaka told a press conference that he disagrees with "arguments that we should stop all social activities because we never know when natural disasters may happen," saying there is a "gap" in perception between him and the volcanologists.
The nuclear safety regulator judged in September that the risk of a massive volcanic eruption near the two-reactor Sendai plant in Kagoshima Prefecture is negligible during the facility's life span.
Public debate about the safety of the Sendai plant has been further fueled by Saturday's eruption of Mount Ontake in central Japan which killed about 50 people.
The Sendai plant, on the island of Kyushu, is only 50 kilometers from Mount Sakurajima, an active volcano.