Members of an expert panel investigating the crisis at the Fukushima No. 1 power plant visited the site for the first time Friday, where they were shocked by the extent of the damage from the March 11 earthquake and tsunami, committee leader Yotaro Hatamura said.

Hatamura, a professor emeritus at the University of Tokyo, was one of four panel members to make the trip. They spent a couple of hours each at the Fukushima No. 1 and No. 2 power plants.

"The biggest impression was that something awful was happening there," Hatamura said at a news conference just before midnight Friday. "The Fukushima No. 2 plant managed to avoid a serious situation because it was able to maintain cooling functions, but the No. 1 plant, unfortunately, became a calamity."