Tokyo Electric Power Co. expects to begin freezing a soil barrier by the end of the year to stop a torrent of water entering the wrecked Fukushima nuclear facility, moving a step closer to fulfilling a promise the government made to the international community more than two years ago.

"In the last half-year we have made significant progress in water treatment," Akira Ono, chief of the Fukushima No. 1 plant, said Friday during a tour of the facility northeast of Tokyo.

The frozen wall, along with other measures, "should be able to resolve the contaminated water issues before the (2020) Olympic Games."