Utilities were unwilling to voluntarily improve safety at their nuclear plants before the Fukushima crisis erupted, but the chairman of the Japan Nuclear Safety Institute, an entity aimed at monitoring efforts by power firms to improve atomic safety, is determined to change that mindset.

"Overseas experts have pointed this out before, but nuclear power station operators and industry regulators in Japan thought they had ensured safety simply by following regulations," said Shojiro Matsuura, who headed the Cabinet Office's now-defunct Nuclear Safety Commission before taking the institute's reins.

Panels set up to investigate the causes of the Fukushima No. 1 plant meltdowns found that the existing regulations were deeply inadequate.