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.
Following are questions about the current state of the plant:
What are the next milestones?
Along with the seaside wall, Tepco is reinforcing the drainage system that collects surface water from various parts of the facility with a new covered channel. Work on the new configuration, which began in May, is expected to be completed by March.
The company also expects to start freezing a soil barrier around the wrecked reactor buildings by the end of the year.
How long will decommissioning take?
Tepco expects it will take another 30 years to 40 years to decommission the Fukushima No. 1 facility.
What is the timeline for removing the spent fuel?
Tepco expects to begin removing spent fuel in the No. 3 reactor in 2017, two years later than it estimated in 2013. Fuel removal in reactors 1 and 2 is expected to begin in 2020.
Tepco is currently removing rubble from the three reactors that melted down. Once rubble is removed and the flow of water into the reactors is stabilized, workers will be able to enter the facility with a greater degree of safety, according to company spokesman Tatsuhiro Yamagishi.
Tepco removed the largest piece of debris from the spent fuel pool inside the No. 3 reactor in August, a milestone for the early stage of decommissioning. Almost all debris removal efforts at No. 3 are complete, according to Akira Ono, chief of the Fukushima No. 1 plant.
How much will the decommissioning cost?
The company estimates that water management and reactor stabilization will cost more than ¥1 trillion in the next 10 years. The company had spent roughly ¥430.6 billion on decommissioning the facility as of June 30, according to Yamagishi.
How many people are working at the site?
About 7,000 contract workers and Tepco employees are at the facility on any given weekday. About half the workers are from the Tohoku region.