In the aftermath of the Fukushima nuclear disaster, the Japanese government established two specialist sub-committees made up of government officials and experts. "Instead of the existing ice wall, we proposed building a much larger and deeper underground impermeable wall. The ice wall is roughly 1.5 kilometers in circumference. Our proposal is to build a much larger impermeable wall, 3.7 kilometers long and 35 to 50 meters deep, that completely cuts off any water from deep underground," said Naoaki Shibasakim, a professor at Fukushima University.