Tokyo Electric Power Co. is scheduled to complete a seaside wall at the Fukushima No. 1 nuclear power station at the end of the month.
Since January, slightly tainted water has overflowed from drainage systems at Fukushima No. 1 into the ocean nine times.
The company, which outlined the progress on the barrier last week during a tour of the facility, expects the completed wall to reduce the flow of contaminated water into the ocean.