The maze-like industrial landscape inside Fukushima Daiichi is complex and disorienting.
Among the scattered debris, buildings overgrown with weeds and abandoned equipment, our bus pulls up alongside an intricate network of small metal pipes and scaffolding that blends into the cluttered landscape.
This is the Ice Wall — the critical front-line defense against Fukushima Daiichi's radioactivity spreading around the world.
A hole dug on the outside of the Ice Wall perimeter shows the high groundwater table. A similar hole on the inside of the perimeter illustrates the lower water level and thus the effectiveness of the Ice Wall's intent.
Water leaking from the damaged reactors has to be stored on site at Fukushima Daiichi.
The fuel rods in the three damaged radioactive units need to be continuously cooled with fresh water, but Tepco must collect and store the leaking (and now contaminated) water.
In the eight years since the accident, that has meant Tepco has collected more than 1.1 million tons of leaking, contaminated water.
Where does it all go? There are currently 900 huge silos on site and counting. Tepco estimates it has enough space in the 37.7-million-square-foot facility to house an additional 270,000 tons of water, which means it will run out space to store any more water sometime in 2020.
The Ice Wall is part of the solution to this problem. Less ground water mixing with contaminated water means then less contaminated water to store in the finite amount of space available.
Tepco's on-site purification process at the Advanced Liquid Processing System is able to remove 62 radioactive elements from the contaminated water used in the cooling Fukushima Daiichi's reactors. Remaining in the water is tritium, a lesser radioactive element that is more complicated to remove from water in purification processes.