Japan says building nuclear safety culture will take a long time

A radiation monitor indicates 131.00 microsieverts per hour near the No.4 and No.3 buildings at the tsunami-crippled Tokyo Electric Power Co. (TEPCO)'s Fukushima Daiichi nuclear power plant in Fukushima prefecture February 28, 2012. REUTERS/Kimimasa Mayama/Pool

TOKYO (Reuters) - Japan's nuclear regulator said on Thursday that elevating safety culture to international standards will "take a long time", days before new rules come into effect to avoid a repeat of the Fukushima nuclear disaster in March 2011.

An earthquake and tsunami killed nearly 20,000 people and triggered the world's worst nuclear crisis in 25 years when the Fukushima-Daiichi nuclear plant was destroyed, leaking radiation into the sea and air.