More than two years into the triple-meltdown crisis at the Fukushima No. 1 power plant, workers continue to wage a desperate battle to keep the stricken reactors cool while trying to contain the 400 tons of radioactive water produced by the process each day.

Tokyo Electric Power Co. must decommission the three reactors, but the water is thwarting the effort. The decommissioning, if it ever starts, will take decades.

Here are some questions and answers on the encroaching problem and its implications for public health and the environment: