TOKYO -- Nearly five years after a devastating earthquake and tsunami, the wreckage that litters the Fukushima Daiichi nuclear plant underscores the massive undertaking of decommissioning the reactors that is expected to take decades.
For this exclusive report, Nikkei was granted special access to the wrecked power station. The Nos. 1, 2 and 3 reactors are visible from a platform to the west. Debris covers the roof of the damaged building housing the No. 3 reactor. The state of the reactor is not fully known as radiation has prevented human access.
While radiation levels have dropped off significantly to between 200 and 300 microsieverts per hour, one cannot stay in the area too long. Removing some 1,500 spent fuel rods from nearby storage pools, starting as early as fiscal 2017, will be a principal task for the near term.
Radiation levels have dropped in many areas, and the roughly 7,000 workers at the plant no longer have to wear full face masks. Hot meals even began to be served last year, providing relief to the over-burdened workers.
Hitting a wall
Tokyo Electric Power Co. finished installing equipment to create a wall of frozen soil, considered key to preventing groundwater from flooding the reactor buildings. But this "ice wall" will require advance approval by the Nuclear Regulation Authority.
Coolant at a temperature of minus 30 C flows through ground pipes fashioned to freeze a 1,500-meter stretch of soil surrounding the Nos. 1-4 reactors. Preparatory work ended with the installation of measuring instruments and other tasks.
Tepco says the wall will cut the daily volume of groundwater flowing into the reactors from about 150 tons to roughly 50 tons.
But a completion date remains to be set. The NRA plans to thoroughly study the barrier's effects on groundwater levels and currents. If groundwater levels drop too steeply, contaminated water from the reactors could seep out.
The authority will hold a meeting next Monday to discuss measures, and Tepco's ability to provide an adequate explanation seen as crucial.
The plant houses about 1,000 tanks holding around 600,000 tons of treated water. Even after a decontamination process, the water still contains radioactive tritium. A way to dispose of the water has yet to be found.