To keep the melted fuel debris stable, TEPCO continuously injects cooling water into the damaged reactors. This process generates massive volumes of highly contaminated wastewater. TEPCO processes this water through the Advanced Liquid Processing System (ALPS) to remove most radionuclides, though remains.
A more obscure but scientifically compelling possibility involves ocean dispersion modeling. In 2012–2013, several papers modeled how the initial radioactive plume would dilute. One study from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) found that within 3–6 months, the concentration of cesium-137 at a distance of 30 km offshore was . An "UPD" from a monitoring buoy might have read: "Offshore reading now one quarter of peak. Continuing diffusion." In the hands of an alarmist, "one quarter Fukushima upd" could sound like a hidden threshold of safety—or danger. one quarter fukushima upd