A Tokyo Electric Power Co. staffer measures the radiation level as others work on the construction of an ice wall at the Fukushima Dai-ichi plant on July 9, 2014.
Kimmimasa Mayama/AFP/Getty Images
Members of a local government council check an outlet of a so-called groundwater bypass system as they inspect the crippled Fukushima Dai-ichi Nuclear Power Station earlier this week.
Tokyo Electric Power Co (TEPCO) workers work on waste water tanks at Japan's Fukushima Daiichi nuclear plant in the town of Okuma, Fukushima prefecture in Japan on June 12, 2013.
Noboru Hashimoto /AFP/Getty Images
As they inspected an underground storage pool near the crippled Fukushima Daiichi nuclear power plant earlier this month, Tokyo Electric Power Co. President Naomi Hirose (4th from left) and other officials wore protective suits and masks. Radioactive water stored in some of the pits has leaked.
Tokyo Electric Power Co./Reuters /Landov
Care managers tend elderly people in March 2012 in Minamisoma, Japan. The home's residents were evacuated eight days after the Fukushima Dai-ichi nuclear power station was crippled by the March 11, 2011 tsunami.
This photo, taken by a remote-controlled endoscope and released by Tokyo Electric Power Co., shows structures assumed to be small size piping or cable conduit inside the beaker-shaped containment vessel of No. 2 reactor at the damaged Fukushima Dai-ichi nuclear power plant.
Workers in protective suits and masks wait to enter the emergency operation center at the crippled Fukushima Dai-ichi nuclear power station on Nov. 12, 2011.
David Guttenfelder /AFP/Getty Images
This file handout picture shows workers spraying water to cool down the spent nuclear fuel in the fourth reactor building at TEPCO's Fukushima Daiichi nuclear power plant.
TEPCO/via AFP/Getty Images
This handout picture, taken by Tokyo Electric Power Co (TEPCO) shows radioactive water on the floor inside the building of a water treatment facility at TEPCO's Fukushima Daiichi nuclear plant.
Japan's Parliamentary Secretary for the Cabinet Office Yasuhiro Sonoda drinks a glass of decontaminated water taken from puddles inside the buildings housing reactors 5 and 6 at the Fukushima No. 1 plant.