The International Atomic Energy Agency's recently released postmortem on the Fukushima nuclear accident of 2011 makes for grim reading and serves as a timely reminder of why the restart of the Sendai nuclear plant in Kyushu is a bad idea.

When an atomic energy advocacy organization delivers multiple harsh assessments of Japan's woeful nuclear safety culture and inadequate emergency countermeasures and disaster management protocols, it's time to wonder how much has really changed in the past five years — and whether restarting any of the nation's nuclear reactors is a good idea.

In 2012, the government established a new nuclear safety watchdog agency called the Nuclear Regulation Authority (NRA) and it now contends that Japan has the strictest nuclear safety regulations in the world. But is that true? And does it matter?