The Nuclear Regulation Authority on Wednesday revised its disaster mitigation guidelines compiled in light of the Fukushima crisis by adding criteria for evacuation and other protective actions against radiation exposure.

According to the revised guidelines, people living within a 5-km radius of a nuclear power plant will be given iodine tablets, which help prevent thyroid cancer, ahead of time so they can promptly take the pills in the event of a fallout crisis.

People living outside the 5-km zone, meanwhile, will be ordered to evacuate if a radiation dose of 500 microsieverts per hour is detected, a tougher criteria than the International Atomic Energy Agency's benchmark of 1,000 microsieverts.