The high radiation estimates in the No. 2 reactor of the stricken Fukushima No. 1 nuclear plant will probably force a rethink of the nationalized utility's robot-based strategy for locating its molten fuel.
According to an analysis of Thursday's abbreviated probe, the radiation in the primary containment vessel is about 650 sieverts per hour, more than the 530 sieverts estimated late last month, Tokyo Electric Power Company Holding Inc. said.
That level could kill a person quickly and indicates the fuel likely burned through the pressure vessel during the meltdown and is somewhere nearby.