Tokyo Electric Power Co. confirmed Tuesday that "something like steam" again issued from the building housing reactor 3, one of three units to suffer core meltdowns in March 2011, at its crippled Fukushima No. 1 nuclear plant.
Tepco said one of its monitoring cameras showed what appeared to be steam escaping from the building's fifth floor just above the reactor container at around 9:05 a.m. Tuesday.
The steam continued to be seen until 10:30 a.m., Tepco officials said.
On July 18, what appeared to be steam also was seen at the fifth-floor level of the reactor 3 building. But no steam was seen the following day.
As rain hit the power plant Monday night, rainwater may have evaporated after falling onto the lid of the reactor container, whose temperature is around 38 degrees.