Workers re-enter stricken reactor

Japan's nuclear safety agency says workers have entered the reactor building of Unit 1 at the damaged Fukushima Daiichi nuclear power plant for the first time since right after the March 11 earthquake.

The plant's operator Tokyo Electric Power said workers were installing six ventilation machines on Thursday in an attempt to absorb radiation from the air inside the building.

The work is expected to take about four or five days.

The utility must lower radiation levels inside the reactor before it can proceed with installing cooling systems, which were knocked out by the quake and tsunami that followed.

Workers have not gone inside the reactor building since it was damaged by a hydrogen explosion on March 12.