World's biggest nuke plant may shut under new guidelines: Japan report

TOKYO (AFP) - The largest nuclear power plant in the world may be forced to shut down under tightened rules proposed by Japan's new nuclear watchdog aimed at safeguarding against earthquakes, a report said on Friday.

Fukushima operator Tokyo Electric Power's vast Kashiwazaki-Kariwa plant in central Japan could be on the chopping block if the Nuclear Regulation Authority (NRA) expands the definition of an active fault.

The movement of a fault - a crack in the earth's crust - can generate massive earthquakes like the one that sparked a tsunami that slammed into the Fukushima Daiichi plant in March 2011, setting off the worst atomic crisis in a generation.

The watchdog is planning to define an active fault as one that moved any time within the past 400,000 years, rather than the current 120,000 to 130,000-year limit, an official told AFP, which could spell the end of the TEPCO plant.